Patent Application
20220401385
The present invention relates to a combination therapy using a PD-1 signaling inhibitor.
The results of recent clinical trials have revealed that the anti-PD-1 antibody therapy is more effective than conventional standard therapies in various cancers (Non-Patent Documents Nos. 1-3). The response rate of PD-1 antibody therapy in terminal lung cancer patients was 20-30%, showing a dramatic improvement compared to conventional anti-cancer drug therapies. However, about one half of the patients were non-responsive. Little is known about why those patients are non-responsive to the PD-1 antibody therapy.
Non-Patent Document No. 1: Bramer J, Reckamp K, et al: Nivolumab versus Docetaxel in Advanced Nonsquamous Non-Small-Cell Lung Cancer. N Engl J Med, 373:1627-1639, 2015
Non-Patent Document No. 2: Hamanishi J, Mandai M, Ikeda T, et al: Safety and Antitumor Activity of Anti-PD-1 Antibody, Nivolumab, in Patients with Platinum-Resistant Ovarian Cancer. J Clin Oncol, 33:4015-4022, 2015
Non-Patent Document No. 3: Motzer R J, Escudier B, McDermott D F, et al: Nivolumab versus Everolimus in Advanced Renal-Cell Carcinoma. N Engl J Med, 373:1803-1813, 2015
It is an object of the present invention to provide a novel therapeutic strategy for anti-PD-1 antibody therapy.
Unlike the conventional anti-cancer drugs which have a direct killing effect on cancer cells, anti-PD-1 antibody therapy inhibits cancer proliferation by activating antitumor immunity. It is expected that antitumor effect can be improved by a combined use of anti-PD-1 antibody and reagents which support antitumor immunity. Such a combination therapy may be applicable to non-responsive patients.
The present inventors have found that antitumor effect is synergistically improved when PD-1 signaling inhibiting antibodies are used in combination with spermidine (a kind of polyamine). Spermidine alone exhibited no antitumor effect in living bodies. Further, spermidine increased the function of oxidative phosphorylation in T cells. From these results, it is considered that substances typified by spermidine which increase the function of oxidative phosphorylation in T cells support antitumor immunity and synergistically inhibit cancer proliferation when used in combination with PD-1 signaling inhibiting antibody.
A summary of the present invention is as described below.
Antitumor effect is synergistically improved if substances that increase the function of oxidative phosphorylation in T cells are used in combination with PD-1 signaling inhibitors.
The present specification encompasses the contents disclosed in the specification and/or drawings of Japanese Patent Application No. 2019-205550 based on which the present application claims priority.
Hereinbelow, the present invention will be described more specifically.
The present invention provides a pharmaceutical composition which increases the function of oxidative phosphorylation in T cells.
T cells are lymphocytes that originate from hematopoietic stem cells born in the bone marrow and which differentiated in the thymus gland, where they mature to express self-tolerant T cell receptor (TCR). T cells mainly exist in the lymphoid tissue and blood and express CD45, CD3, TCR, etc. on their surfaces. Upon recognition of non-self antigen-derived peptide presenting cells (e.g., bacterium-infected cells or cancer cells), T cells are capable of being activated and killing such cells. For T cell activation and division, energy is necessary and produced via the extramitochondrial glycolytic pathway or intramitochondrial oxidative phosphorylation.
The pharmaceutical composition of the present invention may suitably be such that it increases the function of oxidative phosphorylation in (i) naïve T cells expressing CCR7, CD45RA and CD62L but not expressing CD45RO and CD44 or (ii) activated T cells not expressing CCR7, CD45RA and CD62L but expressing CD45RO and CD44, with both (i) and (ii) existing in the peripheral blood, lymph nodes or tumor tissues.
T cells may be isolated as described below. Briefly, lymphocytes are mixed with CD8-recognizing antibody bound to magnetic beads, and subsequently, CD8+ T cells alone are isolated with a magnet. Alternatively, CD8+ T cells are gated and isolated by a flow cytometer from lymphocytes stained with anti-CD8 antibody.
The function of oxidative phosphorylation in T cells may be measured as described below. Briefly, the oxygen consumption rate (OCR) of T cells is measured with an extracellular flux analyzer (Seahorse). Baseline OCR and the OCR for the case where carbonyl cyanide-4 (trifluoromethoxy) phenylhydrazone (FCCP), or a reagent that is activated to the maximum extent upon addition of a mitochondrial function terminating agent (oligomycin, Antimycine A/Rotenone: A/R), is added are compared and calculated (Divakaruni A S, Paradyse A, Ferrick D A, Murphy A N, Jastroch M. 2014. Analysis and Interpretation of Microplate-Based Oxygen Consumption and pH data. In Methods in Enzymology, Volume 547, Chapter 16, 309-354).
If, in the above-described measurement method, baseline OCR is increased, spare respiratory capacity (SRC) is increased, or mitochondrial ATP production rate (mitoATP) is increased, it may well be concluded that the function of oxidative phosphorylation in T cells has increased.
According to the illustration diagram given below, SRC and mitoATP can be calculated by the following formulas.
SRC (pmo; 02/min)=OCRmaximal−OCRbasal
mitoATP (pmol ATP/min)=(OCRbasal−OCRoligo)×5.5
If used for therapy in combination with a PD-1 signaling inhibitor (e.g., PD-1 inhibitory antibody), the pharmaceutical composition of the present invention is capable of enhancing the effect of the PD-1 signaling inhibitor (e.g., anti-tumor effect, anti-infective effect).
Further, by using it in combination with a PD-1 signaling inhibitor (e.g., PD-1 inhibitory antibody), the pharmaceutical composition of the present invention is capable of producing at least one of the following effects:
It is considered that by using the pharmaceutical composition of the present invention in combination with a PD-1 signaling inhibitor, exhausted T cells are decreased and hypermetabolism of T cells is triggered to thereby increase the function of T cells.
By combination therapy using the pharmaceutical composition of the present invention and a PD-1 signaling inhibitor, expression levels of mitochondria-related proteins in CD8+ T cells in draining lymph nodes may be increased or decreased, compared to therapy using the PD-1 signaling inhibitor alone.
The pharmaceutical composition of the present invention may suitably comprise a substance that increases the function of oxidative phosphorylation in T cells as an active ingredient. As a substance that increases the function of oxidative phosphorylation in T cells, a polyamine may be given. Polyamines are straight-chain aliphatic hydrocarbons with two or more amino groups and are ubiquitous in living bodies. Polyamines are present mainly in a cell-bound form. In the blood, they are found in high concentrations in erythrocytes and leukocytes. The mode of action of polyamine is diverse. Polyamines have anti-oxidative effect and anti-inflammatory effect, and it is said that polyamines are associated with long survival or anti-aging. Specific examples of polyamine include, but are not limited to, spermine, spermidine and putrescine. A combination of these polyamines may also be used. As polyamine, spermine, spermidine and putrescine are preferable; spermine and spermidine are more preferable; and spermidine is still more preferable. A polyamine may be in the form of a salt with acid such as hydrochloric acid, methanesulfonic acid, fumaric acid or phosphoric acid. Further, polyamine or a salt thereof may form a hydrate with water, or a solvate with an organic solvent such as methanol or ethanol. Such a salt, hydrate or solvate may be one that is acceptable as a pharmaceutical drug.
Moreover, the present invention provides a pharmaceutical composition which has an effect of increasing the function of oxidative phosphorylation in T cells and is administered before, after or simultaneously with the administration of a PD-1 signaling inhibitor. The pharmaceutical composition of the present invention may comprise a substance that increases the function of oxidative phosphorylation in T cells as an active ingredient. As a substance that increases the function of oxidative phosphorylation in T cells, a polyamine may be given. As regards polyamine, reference should be made to the foregoing description.
As used herein, the term “PD-1 signaling” refers to the signal transduction mechanism which PD-1 bears. As one aspect of this mechanism, PD-1 inhibits T cell activation in collaboration with its ligands PD-L1 and PD-L2. PD-1 (Programmed cell death-1) is a membrane protein expressed in activated T cells and B cells. Its ligands PD-L1 and PD-L2 are expressed in various cells such as antigen-presenting cells (monocytes, dendritic cells, etc.) and cancer cells. PD-1, PD-L1 and PD-L2 work as inhibitory factors which inhibit T cell activation. Certain types of cancer cells and virus-infected cells escape from host immune surveillance by expressing the ligands of PD-1 to thereby inhibit T cell activation.
As PD-1 signaling inhibitors, substances which specifically bind to PD-1, PD-L1 or PD-L2 may be given. Such substances include, but are not limited to, proteins, polypeptides, oligopeptides, nucleic acids (including natural-type and artificial nucleic acids), low molecular weight organic compounds, inorganic compounds, cell extracts, and extracts from animals, plants, soils or the like. These substances may be either natural or synthetic products. Preferable PD-1 signaling inhibitors are antibodies. More preferably, antibodies such as anti-PD-1 antibody, anti-PD-L1 antibody and anti-PD-L2 antibody may be given. Any type of antibody may be used as long as it is capable of inhibiting PD-1 signaling. The antibody may be any of polyclonal antibody, monoclonal antibody, chimeric antibody, single chain antibody, humanized antibody or human-type antibody. Methods for preparing such antibodies are known. The antibody may be derived from any organisms such as human, mouse, rat, rabbit, goat or guinea pig. As used herein, the term “antibody” is a concept encompassing antibodies of smaller molecular sizes such as Fab, F(ab)′2, ScFv, Diabody, VH, VL, Sc(Fv)2, Bispecific sc(Fv)2, Minibody, scFv-Fc monomer or scFv-Fc dimer.
When the pharmaceutical composition of the present invention is administered before, after or simultaneously with the administration of a PD-1 signaling inhibitor, it may be used as an anti-cancer agent, an anti-infective agent or a combination thereof.
When a combination of the pharmaceutical composition of the present invention and a PD-1 signaling inhibitor is administered as an anticancer agent, target cancers or tumors includes, but are not limited to, leukemia, lymphoma (e.g., Hodgkin's disease, non-Hodgkin's lymphoma), multiple myeloma, brain tumors, breast cancer, endometrial cancer, cervical cancer, ovarian cancer, esophageal cancer, stomach cancer, appendix cancer, colon cancer, liver cancer, gallbladder cancer, bile duct cancer, pancreatic cancer, adrenal cancer, gastrointestinal stromal tumor, mesothelioma, head and neck cancer (such as laryngeal cancer), oral cancer (such as floor of mouth cancer), gingival cancer, tongue cancer, buccal mucosa cancer, salivary gland cancer, nasal sinus cancer (e.g., maxillary sinus cancer, frontal sinus cancer, ethmoid sinus cancer, sphenoid sinus cancer), thyroid cancer, renal cancer, lung cancer, osteosarcoma, prostate cancer, testicular tumor (testicular cancer), renal cell carcinoma, bladder cancer, rhabdomyosarcoma, skin cancer (e.g., basal cell cancer, squamous cell carcinoma, malignant melanoma, actinic keratosis, Bowen's disease, Paget's disease) and anal cancer.
When a combination of the pharmaceutical composition of the present invention and a PD-1 signaling inhibitor is administered as an anti-infective agent, target infections include, but are not limited to, bacterial infections [various infections caused by Streptococcus (e.g., group A β hemolytic Streptococcus, Pneumococcus), Staphylococcus aureus (e.g., MSSA, MRSA), Staphylococcus epidermidis, Enterococcus, Listeria, Neisseria meningitis aureus, Neisseria gonorrhoeae, pathogenic Escherichia coli (e.g., 0157:H7), Klebsiella (Klebsiella pneumoniae), Proteus, Bordetella pertussis, Pseudomonas aeruginosa, Serratia, Citrobacter, Acinetobacter, Enterobacter, mycoplasma, Clostridium or the like; tuberculosis, cholera, plague, diphtheria, dysentery, scarlet fever, anthrax, syphilis, tetanus, leprosy, Legionella pneumonia (legionellosis), leptospirosis, Lyme disease, tularemia, Q fever, and the like], rickettsial infections (e.g., epidemic typhus, scrub typhus, Japanese spotted fever), chlamydial infections (e.g., trachoma, genital chlamydial infection, psittacosis), fungal infections (e.g., aspergillosis, candidiasis, cryptococcosis, trichophytosis, histoplasmosis, Pneumocystis pneumonia), parasitic protozoan infections (e.g., amoebic dysentery, malaria, toxoplasmosis, leishmaniasis, cryptosporidiosis), parasitic helminthic infections (e.g., echinococcosis, schistosomiasis japonica, filariasis, ascariasis, diphyllobothriasis latum), and viral infections [e.g., influenza, viral hepatitis, viral meningitis, acquired immune deficiency syndrome (AIDS), adult T-cell leukemia, Ebola hemorrhagic fever, yellow fever, cold syndrome, rabies, cytomegalovirus infection, severe acute respiratory syndrome (SARS), progressive multifocal leukoencephalopathy, chickenpox, herpes zoster, hand-foot-and-mouth disease, dengue, erythema infectiosum, infectious mononucleosis, smallpox, rubella, acute anterior poliomyelitis (polio), measles, pharyngoconjunctival fever (pool fever), Marburg hemorrhagic fever, hantavirus renal hemorrhagic fever, Lassa fever, mumps, West Nile fever, herpangina and chikungunya fever].
When the pharmaceutical composition of the present invention is administered before, after or simultaneously with the administration of a PD-1 signaling inhibitor, it may be used in combination with the PD-1 signaling inhibitor or may be formulated with the PD-1 signaling inhibitor as a single dosage.
When a PD-1 signaling inhibitor and the pharmaceutical composition of the present invention are used in combination, the PD-1 signaling inhibitor and the pharmaceutical composition may be administered separately.
When a PD-1 signaling inhibitor and the pharmaceutical composition of the present invention are formulated as a single dosage, a combination drug containing the PD-1 signaling inhibitor and the pharmaceutical composition of the present invention may be prepared.
The pharmaceutical composition of the present invention is administered to human or animal subjects systemically or locally by an oral or parenteral route.
PD-1 signaling inhibitors (e.g., anti-PD-1 antibody, anti-PD-L1 antibody or anti-PD-L2 antibody) may be dissolved in buffers such as PBS, physiological saline or sterile water, optionally filter—or otherwise sterilized before being administered to human or animal subjects by injection or infusion. To the solution of PD-1 signaling inhibitors, additives such as coloring agents, emulsifiers, suspending agents, surfactants, solubilizers, stabilizers, preservatives, antioxidants, buffers, isotonizing agents and the like may be added. As routes of administration, intravenous, intramuscular, intraperitoneal, subcutaneous or intradermal administration and the like may be selected.
The content of the PD-1 signaling inhibitor (e.g., anti-PD-1 antibody, anti-PD-L1 antibody or anti-PD-L2 antibody) in a preparation varies with the type of the preparation and is usually 1-100% by weight, preferably 50-100% by weight. Such a preparation may be formulated into a unit dosage form.
The dose and the number of times and frequency of administration of PD-1 signaling inhibitor (e.g., anti-PD-1 antibody, anti-PD-L1 antibody or anti-PD-L2 antibody) may vary with the symptoms, age and body weight of the human or animal subject, the method of administration, dosage form and so on. For example, in terms of the amount of the active ingredient, 0.1-100 mg/kg body weight, preferably 1-10 mg/kg body weight, may usually be administered per adult at least once at a frequency that enables confirmation of the desired effect.
The active ingredient of the pharmaceutical composition of the present invention may be contained in a preparation comprising a PD-1 signaling inhibitor. Alternatively, the active ingredient either alone or in admixture with an excipient or carrier may be formulated into tablets, capsules, powders, granules, liquids, syrups, aerosols, suppositories, injections or the like. The excipient or carrier may be of any type that is routinely used in the art and pharmaceutically acceptable, with their type and composition being appropriately changed. As a liquid carrier, for example, water, plant oil or the like may be used. As a solid carrier, saccharides such as lactose, sucrose or glucose, starches such as potato starch or corn starch, cellulose derivatives such as microcrystalline cellulose, and the like may be used. Lubricants such as magnesium stearate, binders such as gelatin or hydroxypropyl cellulose, and disintegrants such as carboxymethyl cellulose, and the like may be added. What is more, antioxidants, coloring agents, flavoring agents, preservatives, and the like may also be added.
The pharmaceutical composition of the present invention may be administered via various routes such as oral, transnasal, rectal, transdermal, subcutaneous, intravenous or intramuscular route.
The content of the active ingredient of the pharmaceutical composition of the present invention varies with the type of the preparation and is usually 1-100% by weight, preferably 50-100% by weight. In the case of a liquid, for example, the content of the pharmaceutical composition of the present invention in the preparation is preferably 1-100% by weight. In the case of a capsule, tablet, granule or powder, the content of the pharmaceutical composition of the present invention in the preparation is usually 10-100% by weight, preferably 50-100% by weight, with the balance being the carrier. The preparation may be formulated into a unit dosage form.
The dose and the number of times and frequency of administration of the pharmaceutical composition of the present invention may vary with the symptoms, age and body weight of the human or animal subject, the method of administration, dosage form and so on. For example, in terms of the amount of the active ingredient, approximately 0.001-1000 mg/kg body weight may usually be administered per adult at least once at a frequency that enables confirmation of the desired effect.
The ratio (in mass) of PD-1 signaling inhibitor (e.g., anti-PD-1 antibody, anti-PD-L1 antibody or anti-PD-L2 antibody) to the active ingredient of the pharmaceutical composition of the present invention is suitably y from 1:2 to 1:0.1, preferably from 1:0.1 to 1:0.001.
The present invention also provides a method of treating cancer, infection or a combination thereof, comprising administering to a human or animal subject a pharmaceutically effective amount of a pharmaceutical composition that increases the function of oxidative phosphorylation in T cells before, after or simultaneously with the administration of a PD-1 signaling inhibitor. Further, the present invention provides use of a pharmaceutical composition that increases the function of oxidative phosphorylation in T cells for treating cancer, infection or a combination thereof, wherein the pharmaceutical composition that increases the function of oxidative phosphorylation in T cells is administered before, after or simultaneously with the administration of a PD-1 signaling inhibitor. Still further, the present invention provides use of a pharmaceutical composition that increases the function of oxidative phosphorylation in T cells in a method for treating cancer, infection or a combination thereof, wherein the pharmaceutical composition that increases the function of oxidative phosphorylation in T cells is administered before, after or simultaneously with the administration of a PD-1 signaling inhibitor.
Screening for drugs that enhance PD-1 signaling inhibitory activity has become possible by using an effect of increasing the function of oxidative phosphorylation in T cells as an indicator based on the findings obtained by the present invention. Therefore, the present invention also provides a method of screening for drugs that enhance PD-1 signaling inhibitory activity using an effect of increasing the function of oxidative phosphorylation in T cells as an indicator. As regards T cells, the effect of increasing the function of oxidative phosphorylation in T cells and the method of measuring the effect, reference should be made to the foregoing description.
Hereinbelow, the present invention will be described in more detail with reference to the following Example.
All mice were maintained under specific pathogen-free (SPF) conditions at the Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University and used under appropriate protocols. C57BL/6 female mice (5 to 6 wk old) were obtained from Charles River Laboratories Japan (Yokohama). Murine colon adenocarcinoma MC38 cells were kindly provided by Dr. Jim Allison (Memorial Sloan-Kettering Cancer Center, New York, N.Y.). This cell line was cultured in DMEM (Invitrogen) containing 10% heat inactivated FBS and 1% antifungal antibiotic (Invitrogen). Absence of infection with mycobacteria was already confirmed. Spermidine (Nakarai) was dissolved in purified water from a fresh, unused vial at each time of use in the series of experiments. The dissolved reagent was diluted with PBS and inoculated into mice (200 μl/mouse).
MC38 cells (5×105) were intradermally injected on the right flank. Ten days after inoculation, PD-L1 antibody (1-111A; prepared by and stored at the Department of Immunology and Genomic Medicine, Graduate School of Medicine, Kyoto University) (Immunology Letters 84 (2002) 57-62) (2 mg/kg), PD-L1 antibody+SPD (2 mg/kg) or SPD alone was administered to mice. Subsequently, PD-L1 antibody was administered 4 times at a regular interval of 5 days, and SPD was administered 8 times at a regular interval of 3 days. Tumors were measured on every alternate day, and tumor volumes were calculated using the formula for typical ellipsoid, π×(length×breadth×height/6).
IFN-γ levels in culture supernatant were measured quantitatively with mouse IFN-γ kit (BioLegend) following the instructions on the kit.
For analyzing draining lymph nodes, cells from axillary, brachial, and inguinal lymph nodes on the right side of tumor-inoculated mice were harvested and mixed. Averaged cell numbers per one lymph node were used as absolute cell numbers. For tumor analysis, tumor tissues were minced into 2- to 3-mm pieces with scissors and digested with collagenase type IV (Thermo Fisher Scientific) using a gentle MACS Dissociator (Miltenyi Biotec). The numbers of tumor cells per mg were used as absolute numbers.
The following antibodies recognizing the indicated antigens were used: CD44 (1M7), CD45.2 (104), CD45.1 (A20), CD8 (53-6.7), CD62L (MEL-14) and Sca-1 (D7) from BioLegend. All flow cytometry experiments were performed on FACS Canto II (BD Biosciences) and analyzed using FlowJo software (FLOWJO, LLC). Apoptosis assay was performed with PI (Sigma) and Annexin (BioLegend) following the instructions on the kits.
Oxygen consumption rates were measured using an XF96 Extracellular Flux Analyzer (Seahorse Bioscience). CD8+ T cells (4×105) per well were seeded in a determined XF96 plate. The four chemical modulators of mitochondrial oxidative phosphorylation, which came with an XF Cell Mito Stress Test Kit (Seahorse Bioscience), were added to the module sequentially. In brief, basal OCR measurement was performed after sequential addition of oligomycin, FCCP, and rotenone/antimycin A. SRC and ATP production rates were calculated by the following formulas:
SRC (pmo; 02/min)=OCRmaximal−OCRbasal
mitoATP (pmol ATP/min)=(OCRbasal−OCRoligo)×5.5.
CD8+ T cells were isolated using mouse CD8 Microbeads (Miltenyi Biotec or Mojo). After washing with PBS twice, 2×106 cells were solubilized in a lysis buffer containing 30 mM Tris-HCl (pH. 7.4), 150 mM NaCl, 10% glycerol, 0.1% SDS, 1% Triton-X-100, 0.05% Na-Doc, 5 mM EDTA (pH. 8.0), protease inhibitor mixture (Roche Molecular Biochemicals) and phosphatase inhibitors (Nacalai Tesque). After measurement of protein concentrations by DC protein assay (Bio-Rad), 4 μg of proteins was mounted on 4 to 20% gradient Mini-PROTEAN TGX Gels (Bio-Rad) and electroblotted onto nitrocellulose membranes, which were then incubated in a blocking buffer of TBS containing 1% BSA. Primary antibody incubations were carried out overnight at 4° C. in blocking buffer. After washing, secondary antibody incubations were carried out at room temperature for 40 min in blocking buffer. Blots were developed with enhanced chemiluminescence (Amersham Pharmacia). Primary antibodies recognizing the following proteins were used: Phospho-mTOR (P-mTOR) (Cat #5536), Phospho-AMPKa (P-AMPK) (#2535), 4E-BP1 (#9644), Phospho-Acetyl-CoA Carboxylase (P-ACC) (#3661) and Phospho-PKCa (#9375). All the primary antibodies were obtained from Cell Signaling Technology.
Quantitative determination of spermidine in medium and cells was performed by liquid chromatograph-tandem mass spectrometry (LC-MS/MS). Spermidine's standard stock solution was diluted with fresh medium, and working solutions of 0.02, 0.05, 0.1, 0.2, and 0.5 μM were prepared. Then, calibration curves were prepared by the external standard method. Spermidine was extracted from medium by liquid-liquid extraction using water-methanol-chloroform, and extracted from cells by ultrasonication in 80% methanol for 30 minutes. The amount of spermidine in cells was determined by calculating the amount contained in 106 cells from the concentration in extract solution.
CD8+ T cells (2×105) were stimulated with 0.2 μM spermidine for 1 hour. Then, cells were harvested, embedded in Ipgell (GenoStaff) and fixed with 4% paraformaldehyde and 2% glutaraldehyde. Images were taken with a transmission electron microscope (TEM). Mitochondrial size was determined with ImageJ software. As regards mitochondrial number, average numbers in single cell were determined with Prism software. Blind testing was used for observation and analysis of mitochondria.
T cells were prepared by two methods. For in vivo analysis, 13 days after tumor inoculation and 3 days after the start of therapy, draining lymph nodes from 5 mice were pooled, followed by isolation of CD8+ T cells. From the isolated CD8+ T cells, three samples each consisting of 1×106 cells were prepared and used for analysis. For in vitro experiments, 2×105 CD8+ T cells stimulated with 0.2 μM spermidine for 1 hour were used. For mass spectrometry analysis, a Tandem Mass Tag (TMT) system or a Data Independent Acquisition (DIA) system was used. In the analysis of in vivo CD8+ T cells (
Statistical analysis was performed using Prism 6. One-way ANOVA analysis (one-way analysis of variance) followed by multiple comparison test was used to analyze three or more variables. For comparison of two groups, Student t test was used. All statistical analyses were two-sided assuming parametric data. P value of <0.05 was considered significant. The variations of data were evaluated as the means±SEM. Five or more samples are believed to be appropriate for the sample size estimate in the current study. Samples and animals were randomly chosen from the pool and treated. No blind testing was used for the treatment of samples and animals.
The present inventors have found that spermidine (SPD) is found in high concentrations in CD3-stimulated T cells or culture thereof. Spermine (SPM), another polyamine, was not detected at high levels in CD3-stimulated cells (
The effect of SPD for enhancing the antitumor immunity of PD-1 inhibition was also confirmed in BALB/c mouse (with different genetic background) or different cancer species (
Since enhancement of metabolism occurs due to SPD, CD8+ T cells in draining lymph nodes were isolated during the combined therapy, and quantitative analysis of mitochondria-related protein abundance (proteomics analysis) was performed. The results revealed that levels of 184 proteins out of 203 mitochondria-related proteins changed significantly in combined therapy, compared to PD-1 inhibition alone therapy. Out of the 184 proteins whose level changed, 172 proteins showed increase in expression (
In order to investigate the T cell activation mechanism of SPD, mitochondrial activity in CD8+ T cells in vitro was examined. CD8+ T cells can be divided by CD44 expression into naïve CD8+ T cells (CD44 low) and effector/memory CD8+ T cells (CD44 high). Because of the difference in reactivity to antigen stimulation, these populations were examined separately. The mitochondrial oxygen consumption (OCR) in CD44 low CD8+ T cells was increased by SPD at any time point of 30 minutes, 1 hour, 2 hours and 72 hours after stimulation (
In order to investigate these differences in reactivity to SPD between CD44 low CD8+ T cells and CD44 high CD8+ T cells, mitochondrial morphology was observed under electron microscope before and after SPD stimulation. As a result, in CD44 low CD8+ T cells, SPD stimulation caused no change in mitochondrial size but produced denser structures of cristae (
It is known from mouse model experiments that the effect of PD-1 inhibitory antibody therapy decreases in aged mice due to their decreased immunity. In order to examine whether combined use of SPD can restore the cancer immunity decreased by aging, 56-week old mice (Charles River Laboratories Japan (Yokohama)) were subjected to the combination therapy. The details are the same methods as described in paragraph [0044]. As a result, PD-1 inhibitory antibody alone did not show a tumor shrinking effect, whereas the combination therapy exhibited an enhanced tumor shrinking effect (
SMP, though slightly less effective than SPD, also induced to some extent an enhancement of the antitumor effect of PD-1 inhibitory antibody (
All publications, patents and patent applications cited herein are incorporated herein by reference in their entirety.
The pharmaceutical composition of the present invention is applicable as an anticancer agent, a therapeutic for infections or a combination thereof if it is combined with a PD-1 signaling inhibitor.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-205550 | Nov 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/041190 | 11/4/2020 | WO |
