Patent Application
20160143969
The present invention relates to a modified coxsitckievirus applicable to treatment of cancer. The present invention is useful in the field of oncolytic virotherapy.
Oncolytic virotherapy (cancer virotherapy) is a therapy in which a virus is allowed to infect cancer cells, and proliferate in cancer tissues to destroy and kill the cancer tissues by utilizing oncolytic property of the virus. Clinical studies are being conducted by using adenovirus and herpes simplex virus, which are DNA viruses, against brain tumor or breast cancer, and results showing safety and efficacy thereof are being reported.
Coxsackievirus group B type 3 (CVB3) (Non-patent documents 1 to 3) has a single strand plus-strand RNA genome, and proliferates only in the cytoplasm, and thus it hardly possibly introduce mutation into a host cell genome. Therefore, it is thought that it can be comparatively safely used in oncolytic virotherapy. Moreover, CVB3 is a common virus, and even if it infects, infection is limited to in apparent infection in many eases. However, there are reports concerning relevance thereof with aseptic meningitis, viral myocarditis, and pancreatitis. Marked oncolytic property of CVB3 against human non-small cell lung cancer has also been reported (Non-patent document 4).
As one of viruses of which application to the oncolytic virotherapy is expected, coxsackievirus group A type 21 (CVA21) is known (Patent document 1), and it has been reported that the virus was proliferated in a tissue-specific manner by incorporating miRNA into the virus genome (Non-patent document 5).
According to the studies of the inventors of the present invention, when wild-type CVB3 (CVB-WT) was evaluated in vivo, elevations of AMY, CK, AST and ALT were observed in serological tests, and destruction of exocrine tissues in the pancreas, inflammatory infiltration in the myocardium, and inflammatory infiltration in the liver were observed in histological diagnoses. It is desirable that these unfavorable actions are reduced.
Therefore, the inventors of the present invention attempted to insert a target sequence of tissue-specific microRNA (miRNA) into the 3′ untranslated region (UTR) of the CVB3-WT genome, and expected that proliferation of the virus would be thereby suppressed in a tissue-specific manner, since, in a tissue containing miRNA, the RISC complex containing, miRNA bound to the inserted target sequence to inhibit translation of virus proteins. In this attempt, the inventors of the present invention paid attention to two of miRNAs, of which use for similar purposes had not been so far examined at all. One is miR-217 considered to be specifically expressed in the pancreas, and the other one is miR-1 considered to be specifically expressed in muscular tissues and normal cells.
Further, during the examination of such insertion of a target sequence of specific miRNA into the genome as mentioned above, it was revealed that replication of the virus was inhibited depending on the position in 3′ UTR at which the target sequence was inserted, and it is necessary to find an appropriate insertion position.
The inventors of the present invention also considered that a modified virus with further enhanced efficacy against tumors would be required for a case in which radical care of tumor could not be realized with CVB3-WT.
The present invention provides the followings.
According to the present invention, safety and antitumor effect of a pharmaceutical composition using an enterovirus can be further enhanced.
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When a numerical value range is represented as “X to Y” in the present invention, the range includes the values X and Y as the minimum and maximum values. The expression “A and/or B” used in the present invention means at least one of A and B.
One embodiment of the modified coxsackievirus provided by the present invention is a modified coxsackievirus containing a mutated genome consisting of the genome of coxsackievirus B3 wild-type (CVB3-WT) inserted with at least one polynucleotide comprising a target sequence of tissue-specific microRNA (miRNA). Proliferation of such a modified coxsackievirus may be suppressed in a tissue-specific manner.
The insertion position of the target sequence of the tissue-specific miRNA preferably a position in the 3′UTR region of the CVB3-WT genome. According to the studies of the inventors of the present invention, genetically modified CVB3 inserted with the target sequence between 7304 and 7305 bp showed proliferation in the HeLa cells, which are common CVB3-producing cells, but genetically modified CVB3 inserted with the sequence between 7344 and 7345 bp did not show proliferation in the same cells. The same phenomenon was also seen in the HeLa cells in which expression of miRNA was suppressed. Therefore, the insertion position is more preferably a position upstream from the position 7344 or downstream from the position 7345 in the CVB3-WT genome, more preferably a position between the positions 7304 and 7305.
The tissue-specific miRNA (and the tar et sequence thereof) to be used can be variously chosen, so long as the intended effect is provided, but it is preferably miRNA expressed in the pancreas and/or myocardium (and the target sequence thereof). Particularly preferred examples of the tissue-specific miRNA are miR-1 and/or miR-217 One kind of tissue-specific miRNA (and the target sequence thereof) may be used, and a plurality of kinds of them may be used in combination.
The number of the target sequence of the tissue-specific miRNA to be inserted can be variously chosen, so long the intended effect is provided, but it is preferably 2 or larger, for example, 2 to 6.
In a particularly preferred embodiment the inserted polynucleotide is the polynucleotide of the sequence of (a) or (b) mentioned below. Alternatively, it is a polynucleotide of the sequence of (a) or (b) that includes deletion, substitution or addition of one to several nucleotides, and can function in the same manner as that of the polynucleotide of the sequence of (a) or (b), that is, can suppress proliferation of a modified coxsackievirus constituted by inserting the polynucleotide into the 3′ UTR region of the CVB3-WT genome in a tissue-specific Manlier. Alternatively, it is a polynucleotide that consists of a sequence showing a sequence identity of at least 90%, preferably 95%, more preterably 98%, still more preferably 99%, to the nucleotide sequence of (a) or (b), and can function in the same manner as that of the polynucleotide of the sequence of (a) or (b), that is, can suppress proliferation of a modified coxsackievirus constituted by inserting the polynucleotide into the 3′ UTR region of the CVB3-WT genome in a tissue-specific manner.
Methods for obtaining a polynucleotide consisting of a certain nucleotide sequence, but including deletion, substitution or addition of one to several nucleotides, and methods for calculating sequence identity (calculation can be performed by using, for example, BLAST algorithm) are well known to those skilled in the art.
In another embodiment of the modified coxsackievirus provided by the present invention, a region encoding the granulocyte-macrophage colony-stimulating factor (GM-CSF) is inserted into the genome of CVB3-WT in an expressible form, in order to insert the region encoding GM-CSF in an expressible form, method for isolating mGM-CSF, insertion site of the gene, and modification of protease recognition sequence can be taken into consideration. Examples of the method for isolating mGM-CSF include use of 3C protease recognition sequence, use of 2A protease recognition sequence, use of IRES, and use of 2A peptide. Examples of the insertion site of the gene include a position immediately downstream from the translation initiation point ATG (upstream of VP4), a position upstream from the 2A gene, and 3′ UTR of the genome of CVB3-WT. Examples of the modification of the protease recognition sequence include modification thereof into a sequence derived from a virus other than CVB3.
According to one of the preferred embodiments, a polynucleotide including the region encoding GM-CSF, and the region encoding the 2A protease recognition sequence ligated downstream is functionally inserted at a position downstream from ATG of the translation initiation point and upstream from the VP4 region.
The structure of the genome of CVB3-WT is shown below.
According to one embodiment of the present invention, as for the recognition sequence of 2A protease (also referred to as “2Apro”), it is preferable to use a sequence modified into a sequence that can be recognized by the 2A protease of poliovirus, rather than to use one derived from CVB3.
In a particularly preferred embodiment, the polynucleotide to be inserted is a polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 4, or a polynucleotide that comprises the sequence of any one of SEQ ID NOS: 3 to 5, preferably the sequence of SEQ ID NO: 4, including deletion, substitution or addition of one to several nucleotides, and can function in the same manner as that of the sequence of SEQ ID NO: 4, that is, can express GM-CSF and exhibit cytopathogenic effect (CPE) when it is inserted into the CVB3-WT genome to constitute a modified coxsackievirus. Alternatively, it is a polynucleotide that consists of a sequence showing sequence identity of at least 90%, preferably 95%, more preferably 98%, further preferably 99%, to the nucleotide sequence of any one of SEQ ID NOS: 3 to 5, preferably the sequence of SEQ ID NO: 4, and can function in the same manner as that of the sequence of SEQ ID NO: 4, that is, can express GM-CSF, and exhibit cytopathogenic effect (CPE) when it is inserted into the CVB3-WT genome to constitute a modified coxsackievirus.
Modification for improving aggressiveness against cancer by insertion of such a polynucleotide encoding GM-CSF or the like may be performed independently, or may be performed in combination with insertion of the aforementioned miRNA target sequence. In a particularly preferred embodiment of the present invention, the miRNA target sequence and the polynucleotide encoding GM-CSF are inserted in combination, since high safety and high oncolytic property can be expected.
The modified virus of the present invention can be prepared by genetically manipulating CVB3-WT. CVB3-WT can be isolated from a sample or the like by a known virus isolation method. Examples of the virus isolation method include centrifugation, proliferation of the virus in cultured cells, and so forth. If a modified coxsackievirus is once prepared, the modified coxsackievirus can be proliferated by using various biological methods for production of virus.
CVB3 to be modified may be obtained by biological selection, which is performed by subculturing a naturally occurring virus many dines in a cell strain so that the virus acquires high infection ability for cancer cells. Examples of cell strain suitable for the biological selection include cancer cell strains that express CAR, DAF and so forth.
The modified coxsackievirus prepared according to the present invention can be evaluated for various aspects such as safety, efficacy, and titer by various in vitro or in vivo means well known to those skilled in the art. For example, aggressiveness against cancer cells (oncolytic property or toxicity) can be confirmed by examining survival of a cancer cell strain exposed to CVB3. Examples of the method for examining survival of a cell strain include, for example, a method of staining immobilized cells with a staining solution, and counting stained live cells, the crystal violet method, a method of quantifying an apoptosis-specific marker, and so forth. By quantifying cancer cells of a cell strain surviving after a predetermined time of incubation with CVB3 using any of the aforementioned methods, cancer cells killed by the cytotoxicity provided by the infection with CVB3 can be quantified as a result.
When the inventors of the present invention produced modified CVB3 (inserted with miRNA target sequence), and measured titer thereof by using the HeLa cells, and H1299 cells, which showed low expression of the miRNA used, the modified CVB3 produced in the H1299 cells showed a virus titer even 5 times higher than that of the modified CVB3 produced in the HeLa cells under the conditions described in the section of examples in this specification. Further, when virus titer of the modified CVB3 produced in the HeLa cells was measured in the H1299 cells and the HeLa cells, the virus titer observed in the H1299 cells was 10 times or more times higher than the virus titer observed in the HeLa cells. Therefore, according to one embodiment of the present invention, the H1299 cells are suitable for the production of the modified virus and virus titer measurement. According to the present invention, it is proposed, for the titer measurement or proliferation of the modified coxsackievirus, to use a cell not showing a large expression amount of corresponding tissue-specific miRNA (for example, H1299 cell).
One embodiment of the pharmaceutical composition provided by the present invention contains the aforementioned modified CVB3 as an active ingredient. Type of cancer as an object of the treatment with the pharmaceutical composition is not particularly limited, and it may be a solid cancer or humoral cancer. CVB3 shows cytotoxicity against cancer cell of solid cancer and humoral cancer. The cytotoxicity of CVB3 against cancer cells is based on lysis of cancer cells provided when the virus infects the cancer cells and replicates in the cytoplasm of the cancer cells, or apoptosis induced by activation of caspase in the cancer cells caused by infection of the virus. CVB3 can recognize CAR on the cell suffice, and infect the cell. The “treatment (to treat)” referred to in the present invention for a disease or condition include a prophylactic treatment and therapeutic treatment.
CVB3 has cytotoxicity against cancer cells of solid cancer and humoral cancer. Solid cancer cells for which especially potent cytotoxicity is induced are cells of a cancer selected from the group consisting of small cell lung cancer, non-small cell lung cancer, lung squamous cell cancer, malignant mesothelioma, colon cancer, colorectal cancer, esophageal cancer, hypopharyngeal cancer, human B lymphoma, breast cancer, and uterine cervix cancer. Therefore, the pharmaceutical composition of this embodiment is preferably applied to any one selected from the group consisting of small cell lung cancer, non-small cell lung cancer, lung squamous cell cancer, malignant mesothelioma, colon cancer, colorectal cancer, esophageal cancer, hypopharyngeal cancer, human B lymphoma, breast cancer, and uterine cervix cancer, as an object.
Lung cancer is a cancer of which number of affected individuals takes higher rank. The pharmaceutical composition of this embodiment would be able to contribute to the treatment of more lung cancer patients. Morbidities of colon cancer and colorectal cancer are increasing in Japan where the Western eating, habits were established, and mortalities are also increasing. The pharmaceutical composition of this embodiment increases the choices of therapeutic drug for colon cancer and colorectal cancer, and it is beneficial to the patients. The recurrence rate of esophageal cancer after surgical resection is as high as 30 to 50%, and the sensitivity thereof to the existing drugs is low. It is expected that the pharmaceutical composition of this embodiment improves the treatment results of esophageal cancer.
Further, the pharmaceutical composition of this embodiment shows potent cytotoxicity against cancer cells resistant to CDDP, gefitinib, or oxaliplatin. Therefore, a treatment effective to so-called intractable cancers that show resistance to these anticancer agents can be provided.
The pharmaceutical composition of this embodiment shows potent cytotoxicity also against cancer stem cells, when the composition contains CVB3. Cancer stem cells are considered to he one of the causes of relapse of cancer, and therefore the composition is useful for prevention of metastasis and relapse of cancer.
The pharmaceutical composition of this embodiment can be in various dosage forms, and can be administered via various administration routes. That is, the pharmaceutical composition of this embodiment can also be a topical preparation, or a preparation for systemic administration. For example, it can be administered as an injection or fusion drip by intratumorale administration, intravenous administration, intrathoracic administration, or intraperitoneal administration according to type of cancer. In particular, in the many cases of gastrointestinal cancers such as esophageal cancer and colon cancer, the pharmaceutical composition can be directly injected into a tumor tissue with visually observing the tumor tissue with an endoscope, or the like. In such a case, since the injection site can be confirmed with an endoscope, or the like, there is also provided an advantage that even if bleeding is observed, it is easily treated. Otherwise, it inn be administered by oral administration, or it may be intramuscularly or subcutaneously administered, or administered via rectum, vagina, nasal cavity, or the like.
The pharmaceutical composition of this embodiment may contain a carrier, diluent, auxiliary agent etc., in addition to the modified CVB3. As the carrier, for example, liposome, micelle, and so forth are preferred. The liposome contains a combination of a lipid and a steroid or steroid precursor that contributes to membrane stability Examples of the lipid include phosphatidyl compounds such as phosphatidylglycerol, phosphatidylcholine, phosphatidylserine, sphingolipids, phosphatidylethanolamine, cerebroside, and ganlioside. With CVB3 contained in liposome or micelle, immune response of a host can be reduced.
Examples of the diluent include, for example, desalted water, distilled water, physiological saline, and so forth. Examples of the auxiliary agent include vegetable oils, cellulose derivatives, polyethylene glycol, fatty acid esters, and so forth.
In the case of oral administration, the pharmaceutical composition may contain a sweetener, disintegrating agent, diluent, coating agent, preservative, and so forth.
The pharmaceutical composition of this embodiment is administered so that the amount of CVB3 is a sufficient for treatment of cancer. Dose is determined on the basis of weight, age, sex of patients, size of tumor tissue, and so forth. For example, when the pharmaceutical composition is used as a solution, it is sufficient that 1×102 to 1×1010 50% tissue culture infectious dose (TCID50) of CVB3, preferably 1×105 TCID50 or more of CVB3, is contained in 1 ml of the solution. The pharmaceutical composition may be administered, at a single time, or may be administered at a plurality of times. The pharmaceutical composition may be continuously administered as a sustained release preparation.
<Combinatory use with Other Preparation>
The pharmaceutical composition of this embodiment may be used together with an anticancer agent. When an anticancer agent of which action mechanism is different from that of the pharmaceutical composition is used in combination, improvement in the antitumor effect can be expected. Although the anticancer agent is not particularly limited, those used for a treatment of small cell lung cancer, non-small cell lung cancer, lung squamous cell cancer, malignant mesothelionia, colon cancer, colorectal cancer, esophageal cancer, hypopharyngeal cancer, human B lymphoma, uterine cervix cancer, pancreatic cancer, and so forth are desirable. Specific examples of the anticancer agents are CDDP (cisplatin), getitinib, oxaliplatin, and so forth.
The pharmaceutical composition of this embodiment of the invention may contain a polynucleotide derived from CVB3 (including modified CVB3, the same shall apply to the following descriptions) that can infect a cancer cell as an active ingredient. The polynucleotide derived from CVIIS may be virus RNA directly isolated from CVB3, synthetic RNA, or cDNA corresponding to a nucleotide sequence of isolated virus RNA. For isolating virus RNA, an arbitrary method can be used. Examples of the method of isolating virus RNA include, for example, a method based on use of phenol/chloroform extraction, and so forth. The polynucleotide may be a virus plasmid or expression vector containing a polynucleotide for producing the virus. Such an expression vector includes, for example, a plasmid that can express RNA encoding a virus protein required for producing the virus. The expression vector may contain a transcription control sequence functionally ligated with the inserted polys polynucleotide. The transcription control sequence referred to here is, for example, a promoter for starting transcription, an expression control element tom enabling binding of ribosome to the transcribed mRNA, or the like.
As the expression vector, for example, pSV2neo, pEF-PGk, pure, pTk2, non-replicable adenovirus shuttle vector, cytomegalovirus promoter, etc. can be used. cDNA encoding a virus protein required for producing virus can be prepared by reverse transcription of a virus RNA or a fragment thereof.
The pharmaceutical composition of this embodiment may contain, for example, a carrier such as liposome, in addition to the polynucleotide derived front CVB3 that can infect a cancer cell. The polynucleotide derived from CVB3 may contain, for example, the polynucleotide consisting of the sequence of SEQ ID NO: 1 or 2, and/or a polynucleotide consisting of any of the sequences of SEQ ID NOS: 3 to 5.
Hereafter, examples of the present invention will be explained. However, the scope of the present invention is not limited by these examples.
I. Improvement in Safety of CVB3 by Insertion of miRNA Target Sequence
The object of this research is reduction of the adverse reaction of oncolytic wild-type CVB3 (CVB-WT) observed in the pancreas and myocardium. CVB3-WT causes especially intense inflammation in the pancreas, and there are confirmed marked elevation of AMY in a serebiochemical test and destruction of exocrine glands in H&E stained tissue images. In order to overcome these problems, the inventors of the present invention inserted a target sequence of tissue-specific microRN A (miRNA) into the genuine 3′ untranslated region (UTR) of CVB3-WT with aiming at achieving the expected reduction of adverse reaction. Since the RISC complex having a tissue-specific miRNA binds to the inserted target sequence of miRNA to inhibit translation of virus protein etc., tissue-specific suppression of the proliferation is enabled.
The inventors of the present invention paid attention to two kinds of MiRNAs, i.e., one is miR-217 considered to be specifically expressed in the pancreas, and the other one is miR-1 considered to be specifically expressed in muscular tissue and normal cells, and combined them to prepare two kinds of miRNA target sequences consisting of four of continuously ligated miRNA target sequences (miR-1×2&miR-217×2, and miR-217×4). The two kinds of target sequences were each inserted into the CVB3 genome between 7304 and 7305 bp by using the overlap extension PCR method. The aforementioned target sequences were also inserted into the CVB3 genome between 7344 and 7345 bp by the overlap extension PCR method (
For both the genetically modified CVB3 (CVB3-miR-1&217T, and CVB3-miR-217T) in which the insertion was made between 7304 and 7305 bp, proliferation was observed in the HeLa cells, which are common CVB3-producing cells, and thus genetically modified CVB3 could be successfully produced. However, for both the genetically modified CVB3 in which the insertion was made between 7344 and 7345 bp, proliferation was not observed in the HeLa cells (
Russell et al., previously reported that when a miRNA target sequence was inserted into 3 UTR of CVA21, tissue-specific suppression of proliferation was induced. However, research of the inventors of the present invention is novel in that they paid attention to miRNAs different from those mentioned by Russell et al., and they used novel miRNAs for which insertion into viral genome has not been reported. In addition, Russell et al. did not refer to at which site of 3′ UTR the insertion should be made to obtain good result, and the finding that the insertion between 7304 and 7305 bp allows normal replication of CVB3 is also considered to be novel.
The term genetically modified CVB3-miRT henceforth refers to one in which the insertion was made between 7304 and 7305 bp. Further, CVB3-miR-1&217T refers to the modified CVB3 inserted with two each of miR-1 and miR-217T shown in
I-2. Difference in proliferation rate caused by difference of insertion sequence and expression amount of endogenous miRNA in Various Cells
When the genetically modified CVB3-miRT was produced by using the HeLa cells, retardation of proliferation was observed only for CVB3-miR-1&217T compared with the other two kinds (CVB3-WT, CVB3-miR-217T) (
Since it was expected from this result that miR-1 was expressed in a large amount in the HeLa cells, expression amounts of endogenous miRNA were quantified by the real-time PCR method in the HeLa cells, BEAS-2B cells, which are normal respiratory epithelium cells, cells of lung cancer cell strains as the objects of treatment (A549 cells, NCI-H1299 cells), AsPC-1 cells, which are cells of pancreatic cancer cell strain, and RD cells, which are malignant rhabdomyoma cells. As a result, it was revealed that the expression amount of miR-1 in the HeLa cells was 20 times or more higher than that observed in the BEAS-2B cells as normal cells, as expected, and the expression amount in the HeLa cells was the second highest following that observed in the RD cells of the malignant rhabdomyoma cell strain. In the cells of both the two kinds of lung cancer cell strains, which are the object of the treatment, expressions of miR-1 and miR-217 were hardly observed (
Since the above results suggested a possibility of miRNA-specific proliferation suppression of the genetically modified CVB3-miRT of the present invention, miR-1 and MiR-217 were introduced by transfection into the NCI-H1299 cells, in which expressions of miR-1 and miR-217 were hardly seen, and it was examined whether suppression of proliferation of CVB3-miRT would be seen. As a result, it was revealed that, in the H1299 cells introduced with miR-1, the oncolytic effect could not be seen for CVB3-miR-1&217T, even when CVB3-miR-1&217T was infected in a 100 times larger amount compared with CVB3-WT (
In order to determine cells appropriate for producing CVB3-miRT in consideration of the aforementioned results, virus production and measurement of the titer were performed by using the HeLa cells, and the H1299 cells, in which expression of miRNA was low. CVB3-miR-1&217T produced in the H1299 cells showed a virus titer even 5 times higher than that of the virus produced in the HeLa cells (
In vivo antitumor effect and toxicity of the genetically modified CVB3 were examined. A tumor (non-small cell lung cancer, NCI-H1299 cells) was inoculated into the right abdominal parts of nude mice on the day 0, and the CVB3 virus was intratumorally administered, from the day 2 every other day, 5 times in total (5×106 TCID50/time).
As a result, the tumor volume (mm3) was suppressed in the CNB3-WT-administered group and CVB3-miRT-administered group (destruction of exocrine glands in the pancreas, inflammatory infiltration in the myocardium, and inflammatory infiltration in the liver were observed in histological diagnoses in CAB3-WT administered group,
Further, when serum amylase (AMY), creatine kinase (CK), and aspartate aminotransferase (AST) were measured, slightly high values were observed in the CVB3-WT-administered group, but in the CVB3-miRT administered group, the values were comparable to those observed for the non-treated group (
This research was performed according to the following protocols.
The following components are mixed in the following order in a 0.2-ml PCR tube on ice.
The following program is executed with a thermal cycler (Bio-Rad).
Log10(TCID50)=L+d(S−0.5)+log10(l/v)
CVB3-WT (2.66×109 TCID50/ml, about 1.88 μl/mouse)
CVB3-miR-1&217T (3.55×108 TCID50/ml, about 14.1 μl/mouse)
CVB3-miR-217T (2.66×108 TCID50/ml, about 19 μl/mouse)
Alternatively, the following operations are performed instead of the operations of 8 and 9 mentioned above.
The inventors of the present invention attempted to prepare a genetically modified virus inserted with the granulocyte-macrophage colony-stimulating factor (GM-CSF) for the purpose of further increasing the tumor regression effect for cases where radical cure of tumor was not obtained with the wild-type CVB3 (CVB-WT).
The inventors of the present invention examined the conditions of the genetic modification with paying attention to the following three points. The first one is the isolation method of mGM-CSF (3CPpro, 2Apro, IRES, 2A peptide). The second one is the insertion site of the gene (directly downstream from the initiation point ATG, upstream from the 2A gene, or 3′ UTR of the genome of CVB3-WT). The third one is the difference in the protease recognition sequence (comparison with sequences derived from other viruses). A table summarizing the examination results is shown below.
[Use of 30pro and Insertion of mGM-CSF Immediately Downstream from ATG (1st Generation and 2nd Generation)]
First, by using 3Cpro, of which use for genetic modification of viruses of the genus Enterovirus had been reported, the insertion was performed immediately downstream from ATG. As a result, the cytopathogenic effect (CPE) was not observed for CVB3 inserted with the mGM-CSF gene. However, for the EGFP-inserted CVB3 (CVB3-EGFP) that was prepared as a control and could be confirmed, expression of EGFP was confirmed as previously reported, and. CPE could be observed (
[Use of 2APro and Insertion of mGM-CF Immediately Upstream from 2A Gene (5th Generation and 6th Generation)]
In consideration of the above results, it was examined which protein isolation method among 3Cpro, 2Apro, IRES, and 2A peptide could derive CPE and isolate mGM CSF. As a result, CVB3 inserted with mGM-CSF immediately upstream from the 2A gene by using 2Apro induced CPE, and expression of mGM-CSF was confirmed by ELISA. Furthermore, when 2Apro recognition sequence inserted simultaneously with mGM-CSF was examined, it was found that CPE was more strongly induced with the 2Apro recognition sequence derived from poliovirus compared with 2Apro recognition sequence derived from CVB3 (
[Use of 2A and Insertion of mGM-CSF Immediately Downstream from ATG (8th Generation)]
In consideration of the above results, attention was paid again to the position immediately downstream from ATG, which was the insertion position of CVB3-EGF P providing high virus titer usable for in vivo experiment. CVB3-mGM-CSF was prepared, in which the insertion was performed immediately downstream from ATG by using 2Apro. CVB3-mGM-CSF showing a high titer usable for the in viro experiment could be obtained. Sufficient virus titer could not be expected with use of poliovirus-derived sequence and 3Cpro as well as insertion of mGM-CSF immediately downstream from ATG (7th generation.
In vivo antitumor effect of genetically modified CVB3-GM-CSF (inserted sequence was the aforementioned 8th generation CVB3-GM-CSF4LTTY, the polynucleotide of SEQ ID NO: 4). Tumor (mouse lung cancer, TC-1 cells) was inoculated in the right abdominal parts of C57BL/6 mice on the day 0, and CVB3-WT or CVB3-GM-CSF was intratumorally administered every other day from the day 4 twice in total (5×106 TCID50/time). As a result, the genetically modified CVB3-GM-CSF exhibited oncolytic property higher than that of WT.
According to the present invention, mGM-CSF was inserted into the genome of Enterovirus virus for the first time, and mGM-CSF was expressed and isolated by methods completely different from those previously reported. The idea of expressing a foreign protein with maintaining the cytopathogenic effect of enterovirus is extremely heretical for enteroviruses of which pathogenicity have been studied, and it is considered that the originality and novelty of the present invention are extremely high.
II-2. Methods Summary p This research was done according to the following protocols.
VP1 product obtained after PCR gel extraction (three kinds of T, TG, and MTNT)
EGFP product obtained after PCR gel extraction
2A product obtained after PCR gel extraction (three kinds of 1 TG, and MTNT)
Since the following procedures are the same as the protocols for CVB3-miRT, they are omitted.
Since the following procedures are the same as the protocols for CVB3-miRT, they are omitted.
CVB3 inserted with the aforementioned 2 kinds each table) of sequences for restriction enzyme is produced, and the sequence of EGFP or mGM-CSF is inserted by using the inserted restriction enzyme sequence. The following is a protocol common to the two kinds. The same operations are performed according to the primer number.
Since the following procedures are the same as the protocols for CVB3-miRT, they are omitted.
[ELISA] (mGM-CSF, R&D)
CVB3-mGMCSF-infected NCI-H1299 cells
CVB3-WT (3.33×108 TCID50/ml, about 15 μl/mouse)
CVB3-mGM-CSF (1.12×108 TCID50/ml, about 45 μl/mouse)
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2014/060988 | 4/17/2014 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61812943 | Apr 2013 | US |
