This application contains a Sequence Listing which has been submitted electronically and is hereby incorporated by reference in its entirety. The Sequence Listing was created on Apr. 28, 2023, is named “23-0678-WO-US SequenceListing ST25.txt” and is 347,784 bytes in size.
The present invention relates to a composition for cancer cell targeting comprising a monomeric streptavidin-expressing strain and a biotinylated compound.
Cancer is currently one of the diseases that cause the most deaths worldwide, and the incidence of cancer is continuously increasing due to an increase in average life expectancy and a decrease in the age of cancer onset. According to the 2013 statistical data provided by the Korean National Cancer Center, the total number of Korean cancer patients enrolled in the Cancer Registry Statistics Department in 2010 is 202,053 and the number of cancer patients has continued to increase.
Therefore, with respect to cancer, omnidirectional research on cancer treatment from cell-level basic research has been conducted worldwide, but the mechanism of cancer development still remains unclear, and it is difficult to prevent cancer recurrence and cure cancer. Thus, demand for anticancer drugs is explosively increasing, and enormous research funds are being invested in research institutes and companies. However, not only high cancer diagnosis and chemotherapy costs that are direct medical costs, but also indirect costs due to contraction of social and economic activities after cancer onset, rehabilitation, and patient care are additionally required, which cause a great economic burden for the families of cancer patients and all members of society. Thus, the introduction of low-cost new technology for cancer treatment is required.
Meanwhile, streptavidin and avidin proteins are proteins having a high binding affinity for biotin, and if their specific interaction with biotin is used, they may be applied to various biological applications, such as the use of anticancer drugs or immune cells that specifically target tumors expressing biotin.
However, the tetrameric form of these proteins may lead to unwanted cross-linking of the biotin conjugates, and thus it is required to develop monomeric streptavidin whose biotin binding activity is maintained. In recent years, monomeric avidin-like proteins have been developed and reported, such as monomeric rhizavidin developed by introducing a mutation into rhizavidin, which is an avidin-like protein, or monomeric proteins developed by fusing streptavidin and rhizavidin sequences. However, in order to use these monomeric avidin-like proteins in biological applications, it is necessary to obtain high-purity proteins with guaranteed solubility through purification processes. In addition, the avidin-like proteins have a problem in that they are rapidly degraded in serum when injected in vivo, which limits their use in clinical research.
In addition, the above-described methods cannot evaluate the biodistribution of microorganisms in real time. Thus, if it is possible to track the biodistribution of commensal microorganisms or pathogenic microorganisms in real time in a non-invasive way, the tracking results may be applied to various biological applications, such as production of beneficial microorganisms and development of treatment methods for pathogenic microorganisms.
Throughout the specification, a number of publications and patent documents are referred to and cited. The disclosure of the cited publications and patent documents is incorporated herein by reference in its entirety to more clearly describe the state of the related art and the present disclosure.
An object of the present invention is to provide a composition for cancer diagnosis and fluorescence imaging, the composition comprising: monomeric streptavidin (mSA)-expressing host cells; and optionally a biotinylated compound.
Another object of the present invention is to provide a method of providing information for determining the biodistribution of cells, the method comprising a step of identifying monomeric streptavidin-expressing host cells in a subject of interest, to which the host cells have been administered, by an imaging means.
Still another object of the present invention is to provide a pharmaceutical composition for preventing or treating cancer, the pharmaceutical composition comprising: a monomeric streptavidin (mSA)-expressing strain; and optionally a biotinylated compound.
However, objects to be achieved by the present invention are not limited to the above-mentioned objects, and other problems not mentioned herein will be clearly understood by those skilled in the art from the following description.
Hereinafter, various embodiments described herein will be described with reference to figures. In the following description, numerous specific details are set forth, such as specific configurations, compositions, and processes, etc., in order to provide a thorough understanding of the present invention. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In other instances, known processes and preparation techniques have not been described in particular detail in order to not unnecessarily obscure the present invention. Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, configuration, composition, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrase “in one embodiment” or “an embodiment” in various places throughout this specification are not necessarily referring to the same embodiment of the present invention. Additionally, the particular features, configurations, compositions, or characteristics may be combined in any suitable manner in one or more embodiments. Unless otherwise stated in the specification, all the scientific and technical terms used in the specification have the same meanings as commonly understood by those skilled in the technical field to which the present invention pertains.
According to one embodiment of the present invention, there is provided a composition for in vivo cell tracking and cancer diagnosis, the composition comprising host cells transformed by introduction of a gene encoding monomeric streptavidin (mSA) thereinto.
According to another embodiment of the present invention, there is provided a method of providing information for cancer diagnosis, the method comprising a step of administering an effective amount of the composition for cancer diagnosis to a subject of interest.
In the present invention, the “streptavidin” is a protein having a high binding affinity for biotin and has been applied to various biological applications due to its specific interaction with biotin. The amino acid sequence of the streptavidin protein may be represented by SEQ ID NO: 1, and the gene encoding the streptavidin may be represented by SEQ ID NO: 2, without being limited thereto.
In the present invention, the “monomeric streptavidin (mSA)” is a streptavidin that exists as a monomer so that the streptavidin may form a tetramer and cause unwanted cross-linking of biotin conjugate.
In the present invention, a gene encoding maltose-binding protein (MBP) may further be introduced into the host cell. The “maltose-binding protein (MBP)” is a part of the maltose/maltodextrin system of Escherichia coli, which is an about 42.5 kDa protein responsible for the uptake and efficient catabolism of maltodextrin. The maltose-binding protein (MBP) may be represented by the amino acid sequence of SEQ ID NO: 3, and the gene encoding the maltose binding protein may be represented by SEQ ID NO: 4, without being limited thereto.
In the present invention, a regulatory gene that regulates the expression of the gene encoding the monomeric streptavidin may be further introduced into the host cell. The term “regulation” or “regulation of expression” may mean that transcription and translation of a specific gene are activated or inhibited.
In the present invention, the regulatory gene may refer to a nucleic acid fragment which structurally comprises a binding site for DNA-dependent RNA polymerase, transcription initiation sites and binding sites for transcription factors, repressor and activator protein binding sites, and any other sequences of nucleotides known to those skilled in the art to act directly or indirectly to regulate the amount of transcription, without being limited thereto.
In the present invention, the regulatory gene may be operably linked 5′ upstream of the initiation codon of the gene encoding the monomeric streptavidin.
In the present invention, the regulatory gene may be at least one selected from the group consisting of a ribosome binding site (RBS), a 5′-untranslated region (5′-UTR), a transcription factor binding site, and an inducible promoter, without being limited thereto.
In the present invention, the “ribosome-binding site (RBS)” is responsible for the recruitment of ribosomes upstream of the initiation codon of the gene to proceed with translation. The prokaryotic ribosome binding site contains a Shine-Dalgarno (SD) sequence having a 5′-AGGAGG-3′ sequence. The 3′ end of 16S rRNA complementarily binds to the Shine-Dalgarno sequence to initiate translation, and the complementary sequence CCUCCU is called the anti-Shine-Dalgarno (ASD) sequence.
In the present invention, the “5′-untranslated region (5′-UTR)” refers to untranslated regions flanking both sides of the 5′ coding region which is translated into amino acids of mRNA. It is considered a junk in the evolutionary process, but is known to play a major role in regulating gene expression.
In the present invention, the transcription factor binding site is a DNA region that serves to turn on or off a specific gene nearby. The transcription factor binding site may be at least one selected from the group consisting of a promoter, an enhancer, and a silencer of the gene encoding the regulatory protein, without being limited thereto.
In the present invention, the “inducible promoter” is a promoter that activates transcription so that a gene linked downstream may be specifically expressed only under specific chemical or physical conditions. For example, the inducible promoter may be the promoter of the LacZ gene, which is expressed in the presence of galactose such as isopropyl-beta-D-1-thiogalactopyranoside (IPTG), the promoter of the arabinose operon araBAD which is expressed only in the presence of L-arabinose, or the promoter of tet whose expression is regulated by tetracycline. Preferably, the inducible promoter may be the promoter of araBAD.
In the present invention, the regulatory gene preferably causes the monomeric streptavidin to be expressed in the periplasm of the host cell when the recombinant vector is transformed into the host cell, because the utilization of the expressed monomeric streptavidin is higher than when the monomeric streptavidin remains inside the host cell or is released without remaining in the periplasm.
In the present invention, the regulatory gene may be one represented by any one of SEQ ID NOs: 26 to 92.
In the present invention, the regulatory gene may have a total Gibbs free energy change (ΔGtotal) of 0 or less. The “total Gibbs free energy change (ΔGtotal)” refers to the difference in Gibbs free energy between before and after an mRNA transcript of the regulatory gene binds to the 30S ribosomal subunit complex during the translation of the monomeric streptavidin. When the total Gibbs free energy change amount (ΔGtotal) is 0 or less, the transcription and translation ability of the gene encoding the monomeric streptavidin may increase. The total Gibbs free energy change (ΔGtotal) may be calculated using Equations 1 and 2 below.
ΔGtotal(ΔGfinal)−(ΔGinitial) [Equation 1]
(ΔGfinal)−(ΔGinitial)=[(ΔGmRNA-rRNA)+(ΔGspacing)+(ΔGstacking)+(ΔGstandby)+(ΔGstart)]−(ΔGmRNA) [Equation 2]
In Equation 1 and Equation 2 above, “ΔGfinal” is the Gibbs free energy change after the 30S ribosomal subunit complex binds to an mRNA transcript of the regulatory gene, and “ΔGinitial” is the Gibbs free energy change before the 30S ribosomal subunit complex binds to the mRNA transcript of the regulatory gene. In addition, in Equation 2 above, “ΔGmRNA-rRNA” is the Gibbs free energy change when a reaction that forms a complex of the mRNA of the regulatory gene and the 30S ribosomal subunit occurs, “ΔGspacing” is a Gibbs free energy penalty that occurs when the spacing between the sequence forming the 30S ribosomal subunit complex and the initiation codon in the mRNA transcript of the regulatory gene is not optimized, “ΔGstacking” is the Gibbs free energy change of nucleotides stacked in the region of the spacing, “ΔGstandby” is the Gibbs free energy penalty when a binding reaction between the standby site of the mRNA transcript of the regulatory gene and a ribosome occurs, “ΔGstart” is the Gibbs free energy change when a reaction that forms an mRNA-tRNA complex occurs, and “ΔGmRNA” is the Gibbs free energy change when the mRNA transcript of the regulatory gene forms a folded complex structure.
In the present invention, each Gibbs free energy change (ΔG) may be calculated by software such as NUPACK, ViennaRNA, or UNAfold, which performs calculations in consideration of variables such as interaction of gene strands in a diluted solution, concentration, complexity of base pairing, and knot structure, without being limited thereto.
In the present invention, the regulatory gene may have a translation initiation rate (TIR) controlled within a specific range so as to maximize the production of the monomeric streptavidin.
In the present invention, the “translation initiation rate (TIR)” may be calculated using Equation 3 below, and is an important factor for gene expression because the translation step in synthetic biology is a step that limits the rate of total protein production.
TIR=exp[k{(ΔGtotal)−(ΔG1total)}] [Equation 3]
In Equation 3 above,
TIR is in units of AU;
k is the Boltzmann constant and may be 0.4 to 0.6 mol/kcal;
ΔGtotal is as defined in Equation 1 above; and
ΔG1total corresponds to the Gibbs free energy change in the vector of the present invention, which does not contain the regulatory gene, and preferably, may correspond to free energy change in the vector which does not contain the regulatory gene and in which the remaining sequences are the same, without being limited thereto. Thus, when the regulatory gene is not contained, the translation initiation rate corresponds to 1 AU.
In the present invention, the regulatory gene is preferably regulated so that the translation initiation rate is 50 to 45,000 AU, preferably 900 to 45,000 AU, because the transformed strain is capable of producing the monomeric streptavidin with high efficiency.
In the present invention, the sequence length of the regulatory gene may be 15 to 39 bp, preferably 26 to 31 bp, without being limited thereto.
In the present invention, the regulatory gene may comprise the gene sequence “AGG” represented by SEQ ID NO: 5, the regulatory gene may comprise the gene sequence “TAGG” represented by SEQ ID NO: 6, and the regulatory gene may comprise the gene sequence “ATAGG” represented by SEQ ID NO: 7, without being limited thereto.
In the present invention, the spacing between the 3′ end of the gene sequence represented by any one of SEQ ID NOs: 5 to 7 in the regulatory gene and the initiation codon may be 6 to 13 bp, preferably 6 to 10 bp. When the spacing is 6 to 13 bp, the Gibbs free energy penalty (ΔGspacing) for the unoptimized spacing between the sequence forming the rRNA complex and the initiation codon in the mRNA transcript may be minimized, resulting in an increase in the expression level of the monomeric streptavidin.
In a preferred example of the present invention, the regulatory gene may have a total Gibbs free energy change (ΔGtotal) of 0 or less as calculated by Equation 1 above, a translation initiation rate (TIR) of 900 to 9,000 AU, and a sequence length of 26 to 31 bp, and may comprise a gene sequence represented by any one of SEQ ID NOs: 5 to 7, and the spacing between the 3′ end of the gene represented by any one of SEQ ID NOs: 5 to 7 and the initiation codon of the gene encoding the monomeric streptavidin may be 6 to 10 bp.
In another preferred example of the present invention, the regulatory gene may be represented by SEQ ID NO: 32 or 36.
In the present invention, transformation may be performed with a vector. The “vector” or gene construct is a means for transferring and expressing a foreign gene in a cell, and the vector of the present invention may be a non-viral vector such as a plasmid, a cosmid, an artificial chromosome or a liposome, or a viral vector such as retrovirus, adenovirus, adenovirus-associated virus (AAV), or phage.
In the present invention, the “plasmid” is an episomal DNA molecule that is separated from chromosomes, has its own origin of replication and is capable of independently proliferating. The plasmid may be recombined with restriction enzymes, and then transferred to a host cell and functions as a vector.
In the present invention, the “cosmid” is a plasmid with cos sites, which are the cohesive end of pi phage, and is mainly used to create a gene library due to the large size of a gene that may be inserted therein.
In the present invention, the “artificial chromosome” is a chromosome whose structure has been artificially changed for use as a vector, and examples thereof include bacterial artificial chromosomes, yeast artificial chromosomes, human artificial chromosomes, and the like.
In the present invention, the “liposome” is a vesicular structure made of one or more artificial lipid bilayers, has a shape similar to that of a cell membrane, and is a drug delivery system that delivers not only a nucleic acid but also a peptide, an antibody, an aptamer or the like due to its ability to incorporate various substances. The efficacy of the liposome depends on the target delivery and penetration capabilities according to the properties of membranes and components.
In the present invention, the “retrovirus” is a virus having a single-stranded positive-sense RNA as a genome, which replicates through a DNA intermediate by reverse transcription.
The retroviral vector is widely used in gene therapy because the viral vector is stably maintained even after cell division after insertion into the chromosome of the host cell.
In the present invention, the “lentivirus” is a type of retrovirus, and is a host-endogenous retrovirus (ERV). The virion particles are slightly polymorphic, 80 to 100 nm in diameter, and spherical in shape, the nucleocapsid (core) is isometric, and the nucleotides are concentric rod-shaped or cone-shaped.
In the present invention, the “adenovirus” is a virus having about 36-kb DNA, has more than 50 genes, and thus a vector may be produced by substituting several genes of the virus with genes to be expressed.
In the present invention, the “adenovirus-associated virus (AAV)” is a satellite virus that has a very small DNA genome and requires adenovirus. When the AAV is used as a vector, it is inserted into a specific region of the human chromosome, causing latent infection.
In the present invention, the recombinant vector may be a constitutive expression vector or an inducible expression vector, and may be derived from, for example, at least one plasmid selected from among pKD13, pCP20, pMA1, pUC19, pJL, pBAD, pET, pGEX, pMAL, pALTER, pCal, pcDNA, pDUAL, pTrc, pQE, pTet, pProEX HT, pPROLar.A, pPROTet.E, pRSET, pSE280, pSE380, pSE420, pThioHis, pTriEx, pTrxFus, Split GFP Fold ‘n’ Glow, pACYCDuet-1, pCDF-1b, pCDFDuet-1, pCOLADuet-1, pLysS, pRSF-1b, pRSFDuet-1, pT7-FLAG, T7Select, pCMV, pBluescript, pBac, pAc, pFastBacHT, pFastBac, pAO815, pPIC, pESC, pCas9, pwtCas9-bacteria, pgRNA-bacteria, and pGRG plasmids, without being limited thereto.
In one example of the present invention, the pKD13 may be about 3.4 kbp in size, and may contain beta-lactamase, Tn5 neomycin phosphotransferase, lambda terminator, and R6K gamma replication origin genes.
In one example of the present invention, the pCP20 plasmid may be about 9.4 kbp in size, and may contain EcoRI, cat, Pstl, HindIII, Ci857, flp, bamHi, beta-lactamase, mobA, mob2, and repA101ts gene regions.
In one example of the present invention, the pMA1 plasmid may be derived from Microcystis aeruginosa f. aeruginosa Kutzing, may be about 2.3 kbp in size, and may contain a HincII gene region.
In one example of the present invention, the pJL plasmid may have an empty backbone and be based on an RNA virus.
In one example of the present invention, the pBAD, pCMV and pCMV plasmids may be expressed in mammalian host cells, contain a CMV and a promoter, and have ampicillin resistance.
In one example of the present invention, the pET, pBluescript, pCal and pcDNA plasmids may be expressed in bacterial host cells, contain a T7 or Lac promoter, and have ampicillin resistance.
In one example of the present invention, the pMAL and pGEX plasmids may be expressed in bacterial host cells, contain a Tac promoter, and have ampicillin resistance.
In one example of the present invention, the pALTER plasmid may be expressed in bacterial host cells, contain a T7 promoter, and have tetracycline resistance.
In one example of the present invention, the pDUAL plasmid may be expressed in bacterial host cells, contain a T7 or Lac promoter, and have kanamycin resistance.
In one example of the present invention, the pTrc plasmid may be expressed in bacterial host cells, contain a trc promoter, and have ampicillin resistance.
In one example of the present invention, the pUC19 plasmid is a vector that is expressed in bacterial host cells, comprises about 2.6-kbp circular double-stranded DNA, and has an MCS region opposite to that of pUC18. The pU19 vector is most widely used for transformation, and host cells into which foreign DNA has been introduced by the pU19 may be distinguished because the color of colonies in a growth medium is different from that of a control group.
In one example of the present invention, the pQE plasmid may contain a T5-lac promoter and have ampicillin resistance.
In one example of the present invention, the pTet plasmid contains a CMV promoter under the control of a regulatory sequence from the tet operon, and thus when cells are co-transfected with the pTet plasmid and the transactivator pTet-tTAk, they may express a protein only in the absence of doxycycline.
In one example of the present invention, the pCas9, pwtCas9-bacteria and pgRNA-bacteria plasmids may be used to express the Cas9 nuclease gRNA using CRISPR technology.
In the present invention, the method of transforming the host cells may be performed according to a conventional introduction method known in the art, and is not particularly limited to any specific method, but examples thereof include a bacterial transformation method, a CaCl2) precipitation method, a Hanahan method with improved efficiency using dimethyl sulfoxide (DMSO) as a reducing agent in the CaCl2) method, an electroporation method, a calcium phosphate precipitation method, a protoplast fusion method, an agitation method using silicon carbide fibers, an agrobacterium-mediated transformation method, a transformation method using PEG, a dextran sulfate-mediated transformation method, a lipofectamine-mediated transformation method, and a desiccation/inhibition-mediated transformation method.
In the present invention, when the host cells are administered to a subject having cancer, the monomeric streptavidin may be effectively expressed only in cancer tissue. Thus, when the host cells of the present invention are administered to a subject having cancer, the viability thereof is preferably lower in normal tissue than in cancer tissue, because there is no infection in the normal tissue and the monomeric streptavidin may be expressed only in the cancer tissue. Here, the normal tissue may be a tissue of an organ selected from the group consisting of lung, liver, and spleen, without being limited thereto.
In the present invention, when the host cells are administered in vivo, the biodistribution of the host cells may be effectively determined.
In the present invention, the host cells may be of any one or more types selected from the group consisting of bacteria, yeast, fungal cells, plant cells, insect cells, and animal cells.
In the present invention, the bacteria may be any one or more selected from among Lactococcus, Leuconostoc, Pediococcus, Enterococcus, Streptococcus, Veilonella, Escherichia, Eubacterium, Pseudomonas, Salmonella, Shigella, Helicobacter, Campylobacter, Yersinia, Listeria, Streptomyces, Peptococcus, Peptostreptococcus, Proteus, Ruminococcus, Enterobacter, Citrobacter, Serratia, Haemophilus, Staphylococcus, Mycobacterium, Clostridium, Bacillus, Micrococcus, Vibrio, Bacteroides, Melissococcus, Kocuria, Aerococcus, Oenococcus, Lactobacillus, Sporolactobacilus, Akkermansia, Bifidobacterium, Butyricicoccus, Butyricimonas, Butyrivibrio, Pseudobutyrivibrio, Weissella, Fusobacterium, Carnobacterium, Propionibacterium, Megasphaera, Alistipes, Allobaculum, Barnesiella, Blautia, Dorea, Hespellia, Holdemania, Lawsonia, Oscillibacter, Parabacteroides, Phascolarctobacterium, Prevotella, Sedimentibacter, Exiguobacterium, Acinetobacter, Capnocytophaga, Neisseria, Sphingomonas, Aggregatibacter, Leptotrichia, Granulicatella, Chryseobacterium, Porphyromonas, Brachybacterium, Enhydrobacter, Paracoccus, Corynebacterium, Rothia, Actinomyces, Dialister, Faecalibacterium, Halomonas, Sutterella, Veillonella, Rhodococcus, Atopobium, Chromohalobacter, Cupriavidus, Methanobrevibacter, Odoribacter, Pyramidobacter, Bilophila, Desulfovibrio, Acidaminococcus, Achromobacter, Agrobacterium, Roseateles, Coprococcus, Turicibacter, Roseburia, Lachnospira, Oscillospira, SMB53, Catenibacterium, Paraprevotella, Adlercreutzia, Slackia, and Thermoanaerobacterium, without being limited thereto.
In the present invention, the yeast may be any one or more selected from among Saccharomyces, Debaromyces, Candida, Kluyveromyces, Pichia, Torulaspora, and Phaffia, without being limited thereto.
In the present invention, the fungus may be any one or more selected from among Aspergillus, Rhizopus, Mucor, Penicillium, and Basidiomycota, without being limited thereto.
In the present invention, the insect cells may be of any one or more types selected from Drosophila and Spodoptera Sf9 cells, without being limited thereto.
In the present invention, the animal cells may be of any one or more types selected from among Chinese hamster ovary (CHO) cells, SP2/0 (mouse myeloma) cells, human lymphoblastoid cells, COS cells, mouse myeloma (NSO) cells, 293T cells, bow melanoma cells, HT-1080 cells, baby hamster kidney (BHK) cells, human embryonic kidney (HEK) cells, and PERC.6 cells (human retinal cells), without being limited thereto.
In the present invention, the host cells may be bacterial cells, preferably an anaerobic strain. When the host cells described above are injected into the human body for the purpose of cancer diagnosis, prevention, and treatment, they may target the inside of cancer tissue, which is an environment that is deficient in oxygen due to incomplete blood vessel formation. Thus, when a recombinant vector capable of simultaneously expressing a reporter protein capable of imaging in real time and an anticancer protein in a balanced manner is introduced into this strain, it makes it possible to diagnose, prevent and treat cancer very effectively.
In one example of the present invention, the bacteria may be at least one selected from the group consisting of Salmonella sp. strains, Clostridium sp. strains, Bifidobacterium sp. strains, and E. coli sp. strains, and more preferably, may be at least one selected from the group consisting of Salmonella typhimurium, Salmonella choleraesuis, and Salmonella enteritidis, and even more preferably, may be Salmonella typhimurium, without being limited thereto.
In the present invention, the “Salmonella typhimurium” is a Salmonella sp. bacterium that causes typhoid fever. The Salmonella typhimurium is a rod-shaped bacillus that has a flagellum and is Gram-negative. The Salmonella typhimurium is weak to heat and dies within minutes at 60° C. Also, the Salmonella typhimurium may cause salmonellosis, a kind of food poisoning, through primary contamination from livestock, wild animals, carriers, milk, eggs or the like and also by salads which are susceptible to secondary infection from contaminated meat, etc.
In the present invention, the “Salmonella choleraesuis” is a well-known Salmonella sp. bacterium that causes hog cholera and infects both humans and animals. The Salmonella choleraesuis is a major Salmonella sp. bacterium that causes acute sepsis. This bacterium is a Gram-negative facultative anaerobic bacillus that has peritrichous flagella and is motile. This bacterium is distinguished from Escherichia coli in that it is not able to decompose lactose, does not form indole, and does not produce hydrogen sulfide. This bacterium optimally grows at a temperature of 35 to 37° C., is capable of proliferating at a temperature of 10 to 43° C., and is killed by heating at 60° C. for 20 minutes. This bacterium optimally grows at a pH of 7.2 to 7.4 and is 0.5 to 0.8×3 to 4 μm in size.
In the present invention, the “Salmonella enteritidis” is a Salmonella sp. bacterium that causes bacterial infection-type food poisoning, and is also called Bacillus enteritidis. The Salmonella enteritidis is a representative bacterium of the genus Salmonella, which may infect all animals and has a very high host adaptability. This bacterium is a Gram-negative, facultative anaerobic bacillus that has peritrichous flagella and is motile. This bacterium is distinguished from Escherichia coli in that it is not able to decompose lactose, does not form indole, and does not produce hydrogen sulfide. This bacterium optimally grows at a temperature of 35 to 37° C., is capable of proliferating at a temperature of 10 to 43° C., and is killed by heating at 60° C. for minutes. It optimally grows at a pH of 7.2 to 7.4 and is 0.5 to 0.8×3 to 4 μm in size.
In the present invention, the “Salmonella infantis” is a strain that causes infection by eggs or poultry meat, and the Salmonella paratyphi and the Salmonella typhi are strains that cause typhoid fever.
In the present invention, the bacteria may be attenuated so that it may exhibit reduced virulence and other side effects when administered to a subject.
In one example of the present invention, the bacteria may express a modified form of a gene encoding at least one selected from the group consisting of aroA, aroC, aroD, aroE, Rpur, htrA, ompR, ompF, ompC, galE, cya, crp, cyp, phoP, phoQ, rfaY, dksA, hupA, sipC, clpB, clpP, clpX, pab, nadA, pncB, pmi, rpsL, hemA, rfc, poxA, galU, cdt, pur, ssa, guaA, guaB, fliD, flgK, flgL, relA, spoA, and spoT.
In another example of the present invention, the bacteria may be attenuated due to lack of guanosine polyphosphate synthesis ability. The guanosine polyphosphate may be guanosine-5-diphosphate-3-diphosphate (ppGpp), and the host cells may lack the ability to synthesize guanosine-5-diphosphate-3-diphosphate (ppGpp), due to modification of a gene encoding either relA that hydrolyzes guanosine-5-diphosphate-3-diphosphate (ppGpp) or spot that synthesizes guanosine-5-diphosphate-3-diphosphate (ppGpp), without being limited thereto.
In the present invention, the method of modifying the gene in the bacteria may be performed by a method of deleting or disrupting various genes known in the art. For example, the method of deleting and disrupting genes may be performed by a method such as homologous recombination, chemical mutagenesis, irradiation mutagenesis, or transposon mutagenesis, without being limited thereto.
The composition of the present invention may further comprise a biotinylated compound. In this case, the monomeric streptavidin that is expressed in the host cells is a biotin-binding protein and may comprise a binding site capable of interacting with biotin.
In the present invention, the biotinylated compound may be obtained by modifying a compound containing at least one amine group, which reacts with biotin, preferably D-biotin, to possess biotin groups using a common biotinylation reagent such as the N-hydroxysuccinimidyl ester of D-biotin (NHS-biotin).
In the present invention, the biotinylated compound may pre-target the monomeric streptavidin expressed in the host cells, and thus when the host cells or the monomeric streptavidin expressed from the host cells and the biotinylated compound are administered in vivo, a compound-biotin-streptavidin complex may be formed with high efficiency in the place where the host cells are located in the living body.
In the present invention, the biotinylated compound may be a biotinylated contrast agent. Here, the contrast agent may be at least one selected from the group consisting of radionuclides, fluorescent labels, enzyme labels, chemiluminescent markers, gold agents, and magnetic agents, but may also be any contrast agent that generates or amplifies one or more signals selected from among alpha rays, gamma rays, positrons, X-rays, ultraviolet rays, visible rays, infrared rays, ultrasonic waves, and magnetic resonance, without being limited thereto.
In the present invention, the radioactive isotope or radionuclide may be any one or more selected from the group consisting of C-11, F-18, Cu-64, N-13, Ga-68, Sc-44, Zr-89, Y-Tc-99m, In-111, I-123, I-124, I-125, I-131, Lu-177, without being limited thereto.
In the present invention, a means for detecting the radioactive isotope or radionuclide may be positron emission tomography (PET) or single photon emission computed tomography (SPECT), without being limited thereto.
The positron emission tomography (PET) is a method in which, when a drug (radioactive drug) conjugated with a radioactive isotope that emits positrons is injected into the body, the emitted positrons in the body combine with adjacent electrons and generate two photons while annihilating, and an image is obtained by detecting the two photons. The single photon emission computed tomography (SPECT) is a method in which a drug conjugated with a radioisotope that emits single photons (gamma rays) is injected into the body, and an image is obtained by detecting the emitted gamma rays in the body.
The positron emission tomography (PET) is a method in which a drug conjugated with a radioactive isotope that emits positrons is injected into the body, and an image is obtained in real time by measuring the positrons emitted in the body, and the brain single photon emission computed tomography (SPECT) is a test that shows the state of cerebral blood flow after injecting an isotope into a blood vessel of a patient.
In the present invention, the fluorescent label may be any one or more selected from the group consisting of piperazines, xanthenes, including but not limited to fluorescein, rhodamine, rhodol, rosamine, and derivatives thereof, coumarins, acridines, furans, indoles, quinolines, cyanines, benzofurans, quinazolinones, benzazoles, boron-dipyrromethenes, and derivatives thereof, without being limited thereto.
In the present invention, the enzyme label may be any one or more selected from the group consisting of horseradish peroxidase (HRP), luciferase, and alkaline phosphatase, without being limited thereto.
In the present invention, the term “in vivo” refers to the inside of the living body of a subject which may be infected or injected with the host cells, and the term “subject” may include both mammals and non-mammals. Here, examples of the mammals include, but are not limited to, humans, non-human primates such as chimpanzees, other ape or monkey species; farm animals such as cattle, horses, sheep, goats, and pigs; domestic animals such as rabbits, dogs, and cats; laboratory animals including rodents, such as rats, mice or guinea pig. In addition, in the present invention, examples of the non-mammals include, but are not limited to, birds or fish.
In the present invention, the cancer may be at least one selected from the group consisting of melanoma, fallopian tube cancer, brain cancer, small intestine cancer, esophageal cancer, lymph gland cancer, gallbladder cancer, blood cancer, thyroid cancer, endocrine cancer, oral cancer, liver cancer, biliary tract cancer, colorectal cancer, rectal cancer, cervical cancer, ovarian cancer, kidney cancer, gastric cancer, duodenum cancer, prostate cancer, breast cancer, brain tumor, lung cancer, undifferentiated thyroid cancer, uterine cancer, colon cancer, bladder cancer, ureter cancer, pancreatic cancer, bone/soft tissue sarcoma, skin cancer, non-Hodgkin's lymphoma, Hodgkin's lymphoma, multiple myeloma, leukemia, myelodysplastic syndrome, acute lymphoblastic leukemia, acute myelogenous leukemia, chronic lymphocytic leukemia, chronic myelogenous leukemia, and solitary myeloma, and preferably, may be at least one selected from the group consisting of melanoma, fallopian tube cancer, brain cancer, small intestine cancer, esophageal cancer, lymph gland cancer, gallbladder cancer, thyroid cancer, endocrine cancer, oral cancer, liver cancer, biliary tract cancer, colorectal cancer, rectal cancer, cervical cancer, ovarian cancer, kidney cancer, gastric cancer, duodenal cancer, prostate cancer, breast cancer, brain tumor, lung cancer, undifferentiated thyroid cancer, uterine cancer, colon cancer, bladder cancer, ureter cancer, pancreatic cancer, bone/soft tissue sarcoma, skin cancer, and myeloma, without being limited thereto.
As used herein, the term “diagnosis” includes determination of a subject's susceptibility to a specific disease or disorder, determination as to whether a subject is presently affected by a specific disease or disorder, determination of prognosis of a subject affected by a specific disease or disorder (for example, identification of pre-metastatic or metastatic cancerous states, determination of stages of cancer, or determination of responsiveness of cancer to therapy), or therametrics (for example, monitoring a subject's condition to provide information as to the efficacy of therapy). For the purpose of the present invention, the term “diagnosis” means determining whether or not the cancer has occurred or the size of cancer tissue.
As used herein, the term “subject” refers to a subject in need of diagnosis, prevention or treatment of cancer, and may include both mammals and non-mammals. Here, examples of the mammals include, but are not limited to, humans, non-human primates such as chimpanzees, other ape or monkey species; farm animals such as cattle, horses, sheep, goats, and pigs; domestic animals such as rabbits, dogs, and cats; laboratory animals including rodents, such as rats, mice or guinea pig. In addition, in the present invention, examples of the non-mammals include, but are not limited to, birds or fish.
As used herein, the term “administration” refers to a process of introducing the active ingredient of the present invention into a subject by any suitable method. The formulation of the composition that is administered as described above is not particularly limited, and the composition may be administered as solid form preparations, liquid form preparations, or aerosol preparations for inhalation, and may also be administered as solid form preparations which are intended to be converted, shortly before use, to liquid form preparations for either oral or parenteral administration. For example, the composition may be formulated and administered in oral dosage forms such as powders, granules, capsules, tablets or aqueous suspensions, external preparations, suppositories, and sterile injection solutions, without being limited thereto.
In addition, in the present invention, pharmaceutically acceptable carriers may be additionally administered together with the host cells or compound of the present invention during the above-described administration. As the pharmaceutically acceptable carriers, a binder, a lubricant, a disintegrant, an excipient, a solubilizer, a dispersant, a stabilizer, a suspending agent, a colorant, a flavoring agent, and the like may be used for oral administration; a buffer, a preserving agent, a pain-relieving agent, a solubilizer, an isotonic agent, a stabilizer, and the like may be used for injection; and a base, an excipient, a lubricant, a preserving agent, and the like may be used for topical administration. The composition of the present invention may be prepared in various dosage forms by being mixed with the pharmaceutically acceptable carriers as described above. For example, for oral administration, the composition may be formulated in the form of tablets, troches, capsules, elixirs, suspensions, syrups, wafers, or the like. For injection, the composition may be formulated in the form of unit dosage ampoules or in multiple-dosage forms. In addition, the composition may be formulated into solutions, suspensions, tablets, capsules, sustained-release preparations, or the like.
Meanwhile, examples of carriers, excipients and diluents suitable for formulation include lactose, dextrose, sucrose, sorbitol, mannitol, xylitol, erythritol, maltitol, starch, gum acacia, alginate, gelatin, calcium phosphate, calcium silicate, cellulose, methyl cellulose, microcrystalline cellulose, polyvinylpyrrolidone, water, methylhydroxy benzoate, propylhydroxy benzoate, talc, magnesium stearate, and mineral oil. In addition, the composition of the present disclosure may further contain a filler, an anticoagulant, a lubricant, a wetting agent, a fragrance, an emulsifier, a preservative, or the like.
The routes of administration of the composition according to the present invention include, but are not limited to, oral, intravenous, intramuscular, intra-arterial, intramedullary, intradural, intracardiac, transdermal, subcutaneous, intraperitoneal, intranasal, gastrointestinal, topical, sublingual and intrarectal routes. Oral or parenteral administration is preferred.
In the present invention, “parenteral” includes subcutaneous, transdermal, intravenous, intramuscular, intra-articular, intra-synovial, intrasternal, intradural, intra-lesional and intra-cranial injection or infusion techniques. The composition of the present invention may also be formulated as suppositories for intrarectal administration.
As used herein, the term “effective amount” refers to a sufficient amount of an agent to provide a desired biological result. That result may be real-time determination of the biodistribution of host cells or induction of any other desired alteration. For example, an “effective amount” for tracking host cells is the amount of a compound disclosed herein required to generate a significant amount of signal for tracking host cells in vivo. An appropriate “effective” amount in any individual case may be determined by one skilled in the art using routine experimentation. In the case of the present invention, the active substance is a composition for tracking cells in vivo. Accordingly, the expression “effective amount” generally refers to an amount of the active substance that has a prophylactic or therapeutic effect. In the case of the present invention, the active substance is an agent for prevention, amelioration or treatment of cancer.
In the present invention, the effective amount of the host cells or the compound may vary depending on various factors, including the type of host cell used, the activity of the specific compound used, the subject' age, body weight, general health, sex and diet, the time of administration, the route of administration, excretion rate, and the drug content, but may be appropriately selected by those skilled in the art and may be 0.0001 to 100 mg/kg/day or 0.001 to 100 mg/kg/day. The composition may be administered once or several times a day. The above dose is not intended to limit the scope of the present invention in any way. The host cells or compound according to the present invention may be formulated into pills, sugar-coated tablets, capsules, liquids, gels, syrups, slurries, or suspensions.
According to another embodiment of the present invention, there is provided a method of providing information for determining cell biodistribution or diagnosing cancer, the method comprising a step of identifying monomeric streptavidin-expressing host cells in a subject of interest, to which the host cells have been administered, by an imaging means.
In the present invention, a biotinylated compound may also be administered to the subject of interest. The biotinylated compound has an effect of enabling determination of the biodistribution of monomeric streptavidin-expressing host cells by binding to the host cells.
As used herein, the term “subject of interest” refers to a subject who has cancer or has a high likelihood of developing cancer, and may include both humans and non-human animals. Here, examples of the non-human animals include, but are not limited to, non-human primates such as chimpanzees, other ape or monkey species; farm animals such as cattle, horses, sheep, goats, and pigs; domestic animals such as rabbits, dogs, and cats; laboratory animals including rodents, such as rats, mice or guinea pig; birds; or fish.
In the present invention, a biotinylated compound may also be administered to the subject of interest. In the present invention, the biotinylated compound has an effect of enabling determination of the size and location of cancer by binding to the monomeric streptavidin-expressing host cells present in cancer cells.
In the present invention, the imaging means may use one or more signals selected from among alpha rays, gamma rays, positrons, X-rays, ultraviolet rays, visible rays, infrared rays, ultrasonic waves, and magnetic resonance. However, the signals may include, without limitation, any signal that is non-invasive or has low invasiveness to the subject of interest and is generated or amplified by the biotinylated compound.
In the present invention, the presence, range, or size of the signal generated or amplified by the biotinylated compound may be measured by the imaging means in the step of identifying monomeric streptavidin-expressing host cells.
In the present invention, arabinose may also be administered to the subject of interest. The arabinose has an effect of enabling the host cells to continuously express the monomeric streptavidin, thereby determining the biodistribution of the host cells.
In the present invention, the step of identifying monomeric streptavidin-expressing host cells may be performed once or multiple times. In the present invention, the identifying step may be performed multiple times based on a specific time point, or may be performed multiple times over a predetermined period of time, thereby determining the biodistribution of the host cells over time and diagnosing the onset of cancer as well as predicting the prognosis of the cancer patient.
When a signal generated by the biotinylated compound is detected in the identifying step of the present invention, it may be predicted that cancer has developed or is highly likely to develop.
In addition, the prognosis of cancer may also be predicted by detecting a signal generated by the biotinylated compound in the identifying step of the present invention.
In the method of providing information according to the present invention, details regarding the host cell, the subject and the biotinylated compound overlap with those described above, and thus detailed description thereof will be omitted below to avoid excessive complexity of the specification.
According to another embodiment of the present invention, there is provided a pharmaceutical composition for preventing or treating cancer, the pharmaceutical composition comprising host cells transformed by introduction of a gene encoding monomeric streptavidin (mSA) thereinto.
According to still another embodiment of the present invention, there is provided a method for preventing or treating cancer, the method comprising a step of administering to a subject of interest an effective amount of the pharmaceutical composition comprising host cells according to the present invention.
In the present invention, a gene encoding maltose-binding protein (MBP) may further be introduced into the host cells.
In the present invention, a regulatory gene that regulates the expression of the gene encoding the monomeric streptavidin may further be introduced into the host cells.
In the present invention, the composition may further comprise a biotinylated compound.
In the present invention, the biotinylated compound may be a biotinylated cancer therapeutic agent. Here, the cancer therapeutic agent may be an anticancer agent which may be any one or more selected from the group consisting of antimetabolites, alkylating agents, topoisomerase antagonists, microtubule antagonists, anticancer antibiotics, plant-derived alkaloids, antibody anticancer agents, molecularly targeted anticancer agents, immune anticancer agents, gene expression inhibitors, ROS-induced prodrugs, aptamers, and radiotherapeutic agents.
In the present invention, the anticancer agent may be any one or more selected from the group consisting of taxol, nitrogen mustard, imatinib, oxaliplatin, rituximab, erlotinib, trastuzumab, gefitinib, bortezomib, sunitinib, carboplatin, sorafenib, bevacizumab, cisplatin, cetuximab, viscumalbum, asparaginase, tretinoin, hydroxycarbamide, dasatinib, estramustine, gemtuzumab ozogamicin, ibritumomabtucetan, heptaplatin, methylaminolevulinic acid, amsacrine, alemtuzumab, procarbazine, alprostadil, holmium nitrate chitosan, gemcitabine, doxifluridine, pemetrexed, tegafur, capecitabine, gimeracil, oteracil, azacytidine, methotrexate, uracil, cytarabine, fluorouracil, fludarabine, enocitabine, decitabine, mercaptopurine, thioguanine, cladribine, carmophor, raltitrexed, docetaxel, paclitaxel, SBT-1214, squamocin, bullatacin, irinotecan, belotecan, topotecan, vinorelbine, etoposide, vincristine, vinblastine, teniposide, doxorubicin, idarubicin, epirubicin, mitoxantrone, mitomycin, bleomycin, daunorubicin, dactinomycin, pirarubicin, aclarubicin, peplomycin, temozolomide, busulfan, ifosfamide, cyclophosphamide, melpharan, altretmin, dacarbazine, thiotepa, nimustine, chlorambucil, mitolactol, lomustine, carmustine, imatinib, gefitinib, ertotinib, tristuzumab, rociletinib, necitumumab, everolimus, ramucirumab, dacomitinib, foretinib, pembrolizumab, ipilimumab, nivolumab, dabrafenib, veliparib, ceritinib, carmustine, cyclophosphamide, ifosfamide, ixabepilone, melphalan, mercaptopurine, mitoxantrone, TS1, lazertinib, bupaline, triapine, and Holliday junction (HJ) inhibitor peptide 2, and preferably, may be any one or more selected from the group consisting of fluorouracil, doxorubicin, gemcitabine, lazertinib, paclitaxel, SBT-1214, squamocin, bullatacin, bupaline, triapine, and Holliday junction (HJ) inhibitor peptide 2, without being limited thereto.
In the present invention, the gene expression inhibitor may be a transcriptional repressor or a protein activity antagonist. The transcriptional repressor may be a substance that inhibits the initiation of transcription or induces the degradation of transcripts.
In the present invention, the transcriptional repressor may be an antisense oligonucleotide, small interference RNA (siRNA), small or short hairpin RNA (shRNA), microRNA (miRNA), or a combination thereof, without being limited thereto.
In the present invention, the antisense oligonucleotide refers to DNA, RNA or a derivative thereof, which comprises a nucleic acid sequence complementary to a specific mRNA sequence and may act to inhibit translation of mRNA into protein by binding to a complementary sequence in mRNA.
In the present invention, the small interference RNA is a nucleic acid that inhibits the expression of a target gene by mediating RNA interference or gene silencing. The small interference RNA refers to RNA that makes a tight hairpin turn and may be used to silence gene expression through RNA interference.
In the present invention, the microRNA is a single-stranded RNA molecule consisting of 21 to 25 nucleotides and may control gene expression in eukaryotes by binding to the 3′-untranslated region (UTR) of mRNA.
In the present invention, the protein activity antagonist is a substance that reduces the activity of a protein, and the activity antagonist may be a natural extract, a chemical substance, or a combination thereof.
In the present invention, the Holliday junction (HJ) inhibitor peptide 2 may be represented by the amino acid sequence of SEQ ID NO: 38, without being limited thereto.
In the present invention, the immune anticancer agent may be an anti-PD-1/PD-L1 immune anticancer agent, and the anti-PD-1/PD-L1 immune anticancer agent may be nivolumab or pembrolizumab, but may include, without limitation, any immune anticancer agent that is related to PD-1 or PD-L1 related to programmed cell death.
In the present invention, the aptamer is a single-stranded oligonucleotide having binding affinity for a predetermined target molecule, and is capable of inhibiting the activity of the target molecule by binding to the target molecule. The aptamer may have various three-dimensional structures depending on the nucleotide sequence thereof, and may have high affinity for a specific substance, like an antigen-antibody reaction. The aptamer may be RNA, DNA, modified nucleic acid, or a mixture thereof, and may be linear or circular in shape.
In the present invention, the radiotherapeutic agent may emit alpha rays or positrons, and may be, for example, any one or more selected from the group consisting of Cu-67, Y-90, 1-131, Lu-177, At-211, Ra-223, and AC-225, without being limited thereto.
As used herein, the term “prevention” refers to, without limitation, any action that blocks, suppresses or delays symptoms caused by the cancer by using the composition of the present invention.
As used herein, the term “treatment” refers to, without limitation, any action that ameliorates or beneficially changes symptoms caused by the cancer by using the composition of the present invention.
In the pharmaceutical composition of the present invention, contents regarding the maltose binding protein, the regulatory gene, the total Gibbs free energy change (ΔGtotal), the translation initiation rate, the host cells, transformation, the cancer, the subject, and administration overlap with those described above, and thus detailed description thereof will be omitted in order to avoid excessive complexity of the specification.
According to the present invention, when monomeric streptavidin-expressing host cells are administered to a subject, the monomeric streptavidin expressed from the host cells may maintain its functionality in vivo. Accordingly, the presence and distribution of the host cells in vivo may be confirmed by administering a biotinylated imaging agent. In addition, when a biotinylated drug for diagnosis, prevention or treatment of cancer is administered together with the host cells targeting cancer, there is an advantage in that the biotinylated drug may bind to the monomeric streptavidin and selectively act only on cancer tissue, thereby making it possible to accurately diagnose the onset of cancer or perform cancer-targeting prevention or treatment.
Hereinafter, the present invention will be described in more detail with reference to examples. These examples are only for explaining the present invention in more detail, and it will be apparent to those skilled in the art that the scope of the present invention according to the subject matter of the present invention is not limited by these examples.
[1-1] Construction of mSA Gene-Inserted Plasmids
In order to construct a plasmid for mSA expression in a recombinant strain, the monomeric streptavidin (mSA) gene represented by SEQ ID NO: 2 was synthesized (Macrogen, Korea), amplified, digested with restriction enzymes EcoRI and SalI, and purified to obtain a gene amplification product which was then cloned into a pBAD24 plasmid digested with the same restriction enzymes, thus constructing a pBAD-mSA (B-mSA) plasmid.
Additionally, in order to increase the expression of the mSA gene, BBa_B0032, BBa_B0030, and BBa_B0034, which are the ribosome binding sites (RBSs) shown in Table 1 below, were each inserted downstream of the promoter, thereby constructing pBAD_RBS 0.3-mSA (B_R0.3-mSA), pBAD_RBS 0.6-mSA (B_R0.6-mSA), and pBAD_RBS 1.0-mSA (B_R1.0-mSA) plasmids.
In addition, in order to increase the expression and solubility of the gene, the mSA gene was amplified using the pBAD-mSA plasmid as a template, and then digested with restriction enzymes EcoRI and HindIII and purified to obtain a gene amplification product which was then cloned into each of pMA1_p2x and pMA1_c2x plasmids digested with the same restriction enzymes, thereby constructing pMA1_p2x-mSA (M_p-mSA) and pMA1_c2x-mSA (M_c-mSA) plasmids.
[1-2] Construction of MBP-mSA-Expressing Plasmids
Next, for use in animal experiments, the maltose binding protein (MBP)-encoding gene represented by SEQ ID NO: 4, the mSA gene represented by SEQ ID NO: 2, and the BBa_B0034 sequence were each cloned into a pBAD24 plasmid, thereby constructing pBAD_p2x-mSA (B_p-mSA), pBAD_c2x-mSA (B c-mSA), pBAD_RBS1-p2x-mSA (B_R1.0-p-mSA), and pBAD_RBS1-c2x-mSA (B_R1.0-c-mSA) plasmids.
In addition, the mSA gene was amplified using the pBAD-mSA plasmid as a template, and then digested with restriction enzymes EcoRI and HindIII, and purified to obtain a gene amplification product which was then cloned into each of pMA1_p2x and pMA1_c2x plasmids digested with the same restriction enzymes, thereby constructing pMA1_p2x-mSA (M_p-mSA) and pMA1_c2x-mSA (M_c-mSA) plasmids.
[1-3] Construction of RBS-Substituted Plasmids
In order to increase the expression level and functionality of mSA, gene constructs in which the existing RBS was substituted with a new regulatory gene were additionally constructed (Table 1 below). First, a sequence library was prepared by analyzing the RBS sequence of the plasmid. Next, the translation initiation rate (TIR) of the B_p-mSA plasmid was analyzed using the RBS calculator (Penn State University) program, and then a regulatory gene library having a translation initiation rate value ranging from 3.97 to 42,889 as calculated by the RBS library calculator was constructed. The regulatory gene constructed according to the library was cloned to substitute for the RBS sequence of the B_p-mSA plasmid, and then the resulting colonies were selected, thereby constructing the final plasmids pBAD R01-p2x-mSA (B_R01-p-mSA), pBAD R02-p2x-mSA (B_R02-p-mSA), pBAD R1-p2x-mSA (B_R1-p-mSA), pBAD R11-p2x-mSA (B_R11-p-mSA), pBAD R12-p2x-mSA (B_R12-p-mSA), pBAD R13-p2x-mSA (B_R13-p-mSA), pBAD R2-p2x-mSA (B_R2-p-mSA), and pBAD R21-p2x-mSA (B_R21-p-mSA) (see Table 1 below).
The name, abbreviation, backbone plasmid and entire sequence of each gene construct obtained in Examples 1-1 to 1-3 are shown in Table 1 below.
[1-4] Calculation of Total Gibbs Free Energy Changes of Regulatory Gene Transcripts
For the sequence from the promoter to the initiation codon of the ribosome binding site (RBS) constructed in Example 1-3, in order to confirm the mSA expression ability of the gene construct depending on the total Gibbs free energy change (ΔGtotal), the total Gibbs free energy change (ΔGtotal) was calculated by calculating the following parameters, and the results are shown in Table 2 below: ΔGmRNA-rRNA which is the Gibbs free energy change when a reaction that forms a complex of the mRNA of the regulatory gene and the 30S ribosomal subunit occurs; ΔGspacing which is a Gibbs free energy penalty that occurs when the spacing between the sequence forming the 30S ribosomal subunit complex and the initiation codon in the mRNA transcript of the regulatory gene is not optimized; ΔGstacking which is the Gibbs free energy change of nucleotides stacked in the region of the spacing; ΔGstandby which is the Gibbs free energy penalty when a binding reaction between the standby site of the mRNA transcript of the regulatory gene and a ribosome occurs; ΔGstart which is the Gibbs free energy change when a reaction that forms an mRNA-tRNA complex occurs; and ΔGmRNA which is the Gibbs free energy change when the mRNA transcript of the regulatory gene forms a folded complex structure. Here, the total Gibbs free energy change (ΔGtotal) was calculated using Equations 1 and 2 below.
ΔGtotal(ΔGfinal)−(ΔGinitial) [Equation 1]
(ΔGfinal)−(ΔGinitial)=[(ΔGmRNA-rRNA)+(ΔGspacing)+(ΔGstacking)+(ΔGstandby)+(ΔGstart)]−(ΔGmRNA) [Equation 2]
[1-5] Calculation of Translational Initiation Rates of Regulatory Genes
In order to confirm the mSA expression ability of the plasmid depending on the translation initiation rate (TIR) of the regulatory gene, the translation initiation rate of each regulatory gene sequence constructed as described above was calculated, and the results are shown in Table 3.
As shown in Table 3, it was confirmed that, among the regulatory genes of the constructed plasmids, the regulatory genes of SEQ ID NOs: 29 to 37 and 65 to 92 had translation initiation rates in the range of 50 to 45,000 AU, and thereamong, the regulatory genes of SEQ ID NOs: 32 and 36 had translation initiation rates in the range of 900 to 9,000 AU.
[1-6] Sequence Analysis of Regulatory Genes
In order to examine the mSA expression ability of the plasmid depending on whether not the regulatory gene sequence comprises the AGG, TAGG or ATAGG sequence and on the spacing between the 3′ end of the AGG sequence and the initiation codon, the regulatory gene sequence of each plasmid and the spacing (unit: bp) between the 3′ end of the AGG sequence and the initiation codon were analyzed, and the results are shown in Table 4 below.
As shown in Table 4, it was confirmed that, among the regulatory genes of the constructed plasmids, the regulatory genes of SEQ ID NOs: 26, 27, 28, 29, 31, 32, 36, 37, 66, 67, 68, 74, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91 and 92 contained the AGG sequence, and in particular, the spacing between the 3′ end of the AGG sequence in the regulatory genes of SEQ ID NOs: 32 and 36 and the initiation codon was 6 to 13 bp. In addition, it was confirmed that, among the regulatory genes of the constructed plasmids, the regulatory genes of SEQ ID NOs: 32, 36, 67, 77, 78, 79, 83, 85, 87, 88, 89, 90, 91 and 92 contained the TAGG or ATAGG sequence.
After each of the plasmids constructed in Example 1 was transformed into a bacterial strain, each of the transformed strains was cultured overnight using an LB solid medium containing ampicillin. Then, the resulting colonies were diluted at a ratio of 1:100 using an LB liquid medium containing antibiotics, and when the OD600 value reached 0.5 to 0.7 during additional culture, arabinose was added to the culture at a final concentration of 0.1%, followed by culturing in a shaking incubator under conditions of 200 rpm and 37° C.
In order to analyze the expression level of the plasmid into which the mSA gene was inserted alone, recombinant E. coli colonies containing each of the plasmids B-mSA, B_R0.3-mSA, B_R0.6-mSA and B_R1.0-mSA constructed in Example 1 were transformed and cultured as described in Example 2. Next, the cultured recombinant E. coli was added to SDS-PAGE sample buffer based on OD4, boiled at 95° C. for 10 minutes, and then loaded on SDS-PAGE to determine the expression level of the protein, and the results are shown in
As shown in
[2-1] SDS-Page
The present inventors examined the mSA expression level of a strain transformed with an MBP-mSA plasmid in which the MBP gene was fused with mSA in order to increase the expression and solubility of mSA. Specifically, M_p-mSA and M_c-mSA plasmids obtained by fusion with the MBP gene were constructed as described in Example 1, and transformation and culture were performed as described in Example 2. When the OD600 value reached 0.5 to 0.7 during culture, isopropyl beta-D-1-thiogalactopyranoside (IPTG) was added to the culture at a final concentration of 0.1 mM, followed by culturing in a shaking incubator under conditions of 200 rpm and 37° C. The cultured recombinant E. coli was added to SDS-PAGE sample buffer based on OD4, boiled at 95° C. for 10 minutes, and then loaded on SDS-PAGE to confirm the expression level of the protein, and the results are shown in
As a result, as shown in
[2-2] Western Blot Analysis
Western blot analysis was performed to analyze the mSA expression level and biotin binding activity of the recombinant strain transformed with the MBP-mSA plasmid. Specifically, the culture of the strain of Example 2 was diluted with PBS to 4×10′ CFU/ml, and the pellet was collected by centrifugation at 13,000 rpm for 5 minutes. The pellet fraction was washed with PBS and mixed with SDS sample buffer containing 0.2% beta-mercaptoethanol (catalog number: EBA-1052, ELPIS BIOTECH) to obtain a strain lysate. Then, the strain lysate was electrophoresed on 12% SDS-PAGE gel, and the protein was transferred from the gel to a nitrocellulose membrane, followed by blocking with 5% skim milk at room temperature. Then, the expression level of mSA was confirmed using his tag antibody, and the biotin-binding activity of mSA was confirmed using biotinylated peroxidase. The results are shown in
As shown in
In addition, it could be confirmed that, although the expression level of the protein expressed from the M_c-mSA plasmid was higher than that from M_p-mSA, the biotin binding activity of MBP-fused mSA with the secretion sequence was higher.
[2-3] Biotin Uptake Assay
In order to analyze the biotin binding activity of the recombinant strain transformed with the MBP-mSA plasmid, biotin uptake assay was performed, and the results are shown in
As a result, as shown in
[2-4] Confocal Microscopic Observation
In order to actually image the binding of the biotinylated fluorescent dye to the recombinant strain, the recombinant strains cultured as described in Example 2 were fixed to slides and observed with a confocal microscope, and the results are shown in
As shown in the biotin uptake assay results in
[3-1] SDS-Page
SDS-PAGE was performed to examine the mSA expression and activity of the recombinant strain transformed with the RBS-added plasmid. Specifically, SDS-PAGE was performed on recombinant strains transformed with each of Bp-mSA and B c-mSA plasmids obtained by cloning the MBP-mSA gene into the pBAD plasmid, and B_R1.0-p-mSA and B_R1.0-c-mSA plasmids obtained by adding the BBa_B0034 sequence to improve the expression of the plasmids, and the results are shown in
As shown in
[3-2] Western Blot Analysis
Western blot analysis was performed to examine the mSA expression and activity of the recombinant strain transformed with the RBS-added plasmid. Western blot analysis was performed on B_p-mSA and B c-mSA plasmids obtained by cloning the MBP-mSA gene into the pBAD plasmid, and B_R1.0-p-mSA and B_R1.0-c-mSA plasmids obtained by adding the BBa_B0034 sequence to improve the expression of the plasmids, in the same manner as in Experimental Example 2-2, and the results are shown in
As shown in
[4-1] Western Blot Analysis (1)
The present inventors analyzed the RBS sequence of the B_p-mSA plasmid to induce increased functional expression of the gene in the recombinant strain, and constructed B_R01-p-mSA, B_R02-p-mSA, B_R1-p-mSA, B_R11-p-mSA, B_R12-p-mSA, B_R13-p-mSA B_R2-p-mSA and B_R21-p-mSA plasmids as described in Example 1. A strain was transformed with each of the constructed plasmids and cultured. In order to examine the protein expression level of each of the recombinant strains, Western blot analysis was performed in the same manner as in Experimental Example 2-2, and the results are shown in
As shown in
[4-2] Western Blot Analysis (2)
Additional experiments were performed on the two selected strains transformed with each of the B_R1-p-mSA and B_R2-p-mSA plasmids having high mSA expression levels, and the results are shown in
As shown in
In addition, it was shown that the secretion level versus expression level of the protein was lower in the recombinant strains containing each of the B_R1-p-mSA and B_R2-p-mSA plasmids than in the recombinant strain containing the Mp-mSA plasmid, indicating that mSA expressed from each of the B_R1-p-mSA and B_R2-p-mSA plasmids remained in the periplasm of the strain. The biotin binding activity was higher in the order of the recombinant strains containing the BAD-mSA, B_R1-p-mSA, Mp-mSA and B_R2-p-mSA plasmids, respectively, and the secreted protein binding activity was higher in the order of the recombinant strains containing the Mp-mSA, BAD-mSA, B_R1-p-mSA, B_R2-p-mSA plasmids, respectively.
[4-3] Biotin Uptake Assay
In addition, in order to analyze the biotin binding activity of the recombinant strain with improved expression, biotin uptake assay was performed in the same manner as in Experimental Example 2, and the results are shown in
As shown in
[4-4] Confocal Microscopic Observation
In order to actually image the binding of the biotinylated fluorescent dye to the recombinant strain, the cultured strains were fixed to slides and observed with a confocal microscope, and the results are shown in
As shown in
[5-1] Biotin Uptake Assay
In order to confirm whether the mSA gene expressed in the constructed recombinant strain of the present invention is specific to biotin, as described in Experimental Example 1, each of the pBAD, B-mSA, Bp-mSA, B_R1-p-mSA and B_R2-p-mSA plasmids was transformed into each of E. coli and Salmonella strains which were then cultured. Next, biotin uptake assay was performed in the same manner as in Experimental Example 2, and the results are shown in
As shown in
[5-2] Tracking of Strain in Muscle Tissue (1)
In order to confirm the strain tracking effect in muscle tissue according to the present invention, an in vivo imaging system (IVIS) imaging was performed. Specifically, 1×109 CFUs of the recombinant strain transformed with B_R2-p-mSA was injected intramuscularly (IM) into the right thigh of each mouse (BALB/C). Then, arabinose was injected to express mSA in the recombinant strain, and arabinose was not injected into the control group. Subsequently, biotin-dye was injected into each of the experimental group and the control group, the signal was examined, and the results are shown in
As shown in
[5-3] Tracking of Strain in Muscle Tissue (2)
In order to confirm whether the recombinant strain of the present invention is actually distributed in muscle tissue, the present inventors harvested the right thigh tissue, into which the strain was injected in Experimental Example 5-2, and counted the CFUs of the strain. Specifically, the present inventors harvested the right thigh tissue from each of the mouse (Induction) showing the signal of the recombinant strain, caused by biotin staining, and the control mouse (Non-induction), which were used in Experimental Example 5-2, and counted the CFUs of the strain remaining therein. The results are shown in
As shown in
[5-4] Tracking of Strain Administered Intraperitoneally (1)
In order to confirm the strain tracking effect according to the present invention, in vivo imaging system (IVIS) imaging was performed on the strain injected intraperitoneally. Specifically, 5×109 CFU of the recombinant strain transformed with B_R2-p-mSA were injected intraperitoneally (IP) into each mouse (BALB/C). Then, arabinose was injected to express mSA in the recombinant strain, and arabinose was not injected into the control group. Subsequently, biotin-dye was injected into each of the experimental group and the control group, the signal was examined, and the results are shown in
As shown in
[5-5] Tracking of Strain Administered Intraperitoneally (2)
In order to confirm whether the recombinant strain of the present invention is actually distributed in the abdominal cavity and intestinal tract, the CFUs of the strain in the bowel harvested in Experimental Example 5-4 above were counted. Specifically, the present inventors harvested the bowel from each of the mouse (Induction) showing the signal of the recombinant strain, caused by biotin stain, and the control mouse (Non-induction), which were used in Experimental Example [5-4], and counted the CFUs of the strain remaining therein. The results are shown in
As shown in
[5-6] Tracking of Strain Administered Intravenously (1)
In order to confirm the strain tracking effect according to the present invention, in vivo imaging system (IVIS) imaging was performed on the strain injected intravenously. Specifically, 1×109 CFU of the recombinant strain transformed with B_R2-p-mSA were injected intravenously (IV) into each mouse (BALB/C). Then, arabinose was injected to express mSA in the recombinant strain, and arabinose was not injected into the control group. Subsequently, biotin-dye was injected into each of the experimental group and the control group, the signal was examined, and the results are shown in
As shown in
[5-7] Tracking of Strain Administered Intravenously (2)
In order to confirm whether the recombinant strain of the present invention is actually distributed in organs, the present inventors counted the CFUs of the strain in the liver harvested in Experimental Example 5-6. Specifically, the present inventors harvested the liver and spleen from each of the mouse (Induction) showing the signal of the recombinant strain, caused by biotin stain, and the control mouse (Non-induction), which were used in Experimental Example 5-6, and counted the CFUs of the strain remaining therein. The results are shown in
As shown in
[5-8] Tracking of Strain Administered Orally (1)
In order to confirm the strain tracking effect according to the present invention, in vivo imaging system (IVIS) imaging was performed on the strain administered orally. Specifically, 1×109 CFU of the recombinant strain transformed with B_R2-p-mSA were orally administered to each mouse (BALB/C). Then, arabinose was injected to express mSA in the recombinant strain, and arabinose was not injected into the control group. Subsequently, biotin-dye was injected into each of the experimental group and the control group, the signal was examined, and the results are shown in
As shown in
[5-9] Tracking of Strain Administered Orally (2)
In order to confirm whether the recombinant strain of the present invention is actually distributed in the intestinal tract, the present inventors counted the CFUs of the strain in the bowel harvested in Experimental Example 5-8 above. Specifically, the present inventors harvested the bowel from each of the mouse (Induction) showing the signal of the recombinant strain, caused by biotin stain, and the control mouse (Non-induction), which were used in Experimental Example 5-8, and counted the CFUs of the strain remaining therein. The results are shown in
As shown in
Specifically, through the above experiments, it was confirmed that, when the recombinant vector or construct according to the present invention, especially the regulatory gene according to the present invention, is included, the monomeric streptavidin (mSA) expressed has excellent stability and can strongly bind to external biotin, and this is effective even in vivo, and treatment with the biotinylated fluorescent dye may be performed multiple times or at adjusted time intervals.
[5-10] Tumor Imaging Assay (1)
In order to confirm the biotin binding activity of the recombinant strain of the present invention, in vivo imaging system (IVIS) imaging was performed. Specifically, first, the CT26 cell line was subcutaneously injected into the flanks of Balb/c mice to construct tumor animal models. Each recombinant strain was injected into the tumor animal model, and as a control, only dye was injected into the tumor animal model. The recombinant strains were those transformed with B-mSA, 13p-mSA, B_R2-p-mSA (non-induction) and B_R2-p-mSA, respectively. After 3 days, biotinylated fluorescent dye was injected into each mouse. The results of IVIS imaging performed 6 hours after biotinylated fluorescent dye injection are shown in
As shown in
[5-11] Tumor Imaging Assay (2)
In addition, in order to confirm the biotin binding activity of the recombinant strain of the present invention, cancer tissue was harvested from the tumor animal model and imaged with an in vivo imaging system (IVIS). Specifically, 24 hours after the biotinylated fluorescent dye was injected into the tumor animal model, the tumor was harvested from each group and imaged with an IVIS to detect the signal of the biotinylated fluorescent dye, and the results are shown in
As shown in
[5-12] Tumor Imaging Assay (3)
In order to confirm the multiple-biotin-binding activity of the recombinant strain of the present invention, in vivo imaging system (IVIS) imaging was performed. Specifically, first, the CT26 cell line was subcutaneously injected into the flanks of Balb/c mice to construct tumor animal models. The recombinant strain was injected into the tumor animal models. Three days after injecting the recombinant strain into the tumor animal models, the biotinylated fluorescent dye was injected (first injection). Two days later, the biotinylated fluorescent dye was injected into the same tumor animal models (second injection). IVIS imaging was performed before, 6 hours after, and 9 hours after the first injection of the fluorescent dye, and then IVIS imaging was performed before, 6 hours after, and 9 hours after the second injection of the fluorescent dye, and the results are shown in
As shown in
Specifically, through the above experiments, it was confirmed that, when the recombinant vector or construct according to the present invention, especially the regulatory gene according to the present invention, is included, the monomeric streptavidin (mSA) expressed has excellent stability and can strongly bind to external biotin, and this is effective even in vivo, and treatment with the biotinylated fluorescent dye may be performed multiple times or at adjusted time intervals.
Although the present invention has been described in detail with reference to the specific features, it will be apparent to those skilled in the art that this description is only description of a preferred embodiment thereof, and does not limit the scope of the present invention. Thus, the substantial scope of the present invention will be defined by the appended claims and equivalents thereto.
Number | Date | Country | Kind |
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10-2020-0143546 | Oct 2020 | KR | national |
10-2021-0006608 | Jan 2021 | KR | national |
This application is a U.S. National Stage entry of International Patent Application no. PCT/KR2021/015411, filed Oct. 29, 2021, which claims the benefit of priority of Korean Patent Application no. 10-2021-0006608, filed Jan. 18, 2021, and Korean Patent Application no. 10-2020-143546, filed Oct. 30, 2020.
Filing Document | Filing Date | Country | Kind |
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PCT/KR2021/015411 | 10/29/2021 | WO |