[Show abstract][Hide abstract] ABSTRACT: Recent progress in fundamental understanding of tumor immunology has opened a new avenue of cancer vaccines. Currently, the development of new cancer vaccines is a global topic and has attracted attention as one of the most important issues in Japan. There is an urgent need for the development of guidance for cancer vaccine clinical studies in order to lead to drug development. Peptide vaccines characteristically have the effect of indirectly acting against cancer through the immune system – a mechanism of action that clearly differs from anticancer drugs that exert a direct effect. Thus, the clinical development of cancer peptide vaccines should be planned and implemented based on the mechanism of action, which differs significantly from conventional anticancer drug research. The Japanese Society for Biological Therapy has created and published Guidance for peptide vaccines for the treatment of cancer as part of its mission and responsibilities towards cancer peptide vaccine development, which is now pursued globally. We welcome comments from regulators and business people as well as researchers in this area.
Cancer Science 07/2014; 105(7). · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chemoradiation therapy (CRT) has been widely used for unresectable esophageal squamous cell carcinoma (ESCC) patients. However, many patients develop local recurrence after CRT. In this study, we hypothesized that the immunotherapy by peptide vaccine may be effective for the eradication of minimal residual cancer cells after CRT. This study was conducted as a phase I clinical trial of multiple-peptide vaccine therapy combined with CRT on patients with unresectable ESCC.Patients and methods: HLA-A*2402 positive 11 unresectable chemo-naive ESCC patients were treated by HLA-A*2402-restricted multi-peptide vaccine combined with CRT. The peptide vaccine included the 5 peptides as follows; TTK protein kinase (TTK), up-regulated lung cancer 10 (URLC10), insulin-like growth factor-II mRNA binding protein 3 (KOC1), vascular endothelial growth factor receptor 1 (VEGFR1) and 2 (VEGFR2). CRT consisted of radiotherapy (60 Gy) with concurrent cisplatin (40 mg/m2) and 5-fluorouracil (400 mg/m2). Peptide vaccines mixed with incomplete Freund's adjuvant were injected subcutaneously once a week on at least 8 occasions combined with CRT.
Vaccination with CRT therapy was well-tolerated, and no severe adverse effects were observed. In the case of grade 3 toxicities, leucopenia, neutropenia, anemia and thrombocutopenia occurred in 54.5%, 27.3%, 27.3% and 9.1% of patients, respectively. Grade 1 local skin reactions in the injection sites of vaccination were observed in 81.8% of patients. The expressions of HLA class I, URLC10, TTK, KOC1, VEGFR1 and VEGFR2 antigens were observed in the tumor tissues of all patients. All patients showed peptide-specific cytotoxic T lymphocytes responses in at least one of the 5 kinds of peptide antigens during the vaccination. Six cases of complete response (CR) and 5 cases of progressive disease (PD) were observed after the 8th vaccination. The 4 CR patients who continued the peptide vaccination experienced long consistent CR for 2.0, 2.9 4.5 and 4.6 years.
A combination therapy of multi-peptide vaccine with CRT can successfully be performed with satisfactory levels of safety, and application of this combination therapy may be an effective treatment for patients with unresectable ESCC.Trial registration: ClinicalTrial.gov, number NCT 00632333.
Journal of Translational Medicine 04/2014; 12(1):84. · 3.99 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Identification of peptides that activate both tumor-specific helper T (Th) cells and cytotoxic T lymphocytes (CTLs) are important for the induction of effective antitumor immune responses. We focused on a long peptide (LP) derived from lymphocyte antigen 6 complex locus K (LY6K) encompassing both candidate Th epitopes and a known CTL epitope. Using IFNγ ELISPOT assays as a marker of activated T cells, we studied the immunogenicity and cross-priming potential of LY6K-LP, assaying human immune cell responses in vitro and immunologic activities in HLA-A24 transgenic mice in vivo. We identified LY6K172-191-LP as an effective immunogen spanning naturally processed epitopes recognized by T helper type 1 (Th1) cells and CTLs. LY6K-specific CTLs were induced through cross-presentation of LY6K172-191-LP in vitro and in vivo. In addition, LY6K172-191-LP enhanced induction of LY6K-specific CTLs among the peripheral blood mononuclear cells (PBMCs) of head-and-neck malignant tumor (HNMT) patients. LY6K172-191-LP-specific Th1 immunologic response following 1 week in vitro stimulation of PBMCs with LY6K172-191-LP were detected in 16 of 21 HNMT patients (76%) vaccinated with CTL-epitope peptides and 1 of 11 HNMT patients (9%) prior to vaccination, but not in 9 healthy donors. Our results are the first to demonstrate the presence of LY6K-specific Th1 cell responses in HNMT patients and underscore the possible utility of LY6K172-191-LP for the induction and propagation of both LY6K-specific Th1 cells and CTLs.
[Show abstract][Hide abstract] ABSTRACT: We recently identified a novel cancer-testis antigen, cell division cycle associated 1 (CDCA1) using genome-wide cDNA microarray analysis, and CDCA1-derived cytotoxic T lymphocyte (CTL)-epitopes. In this study, we attempted to identify CDCA1-derived long peptides (LPs) that induce both CD4+ helper T (Th) cells and CTLs. We combined information from a recently developed computer algorithm predicting HLA class II-binding peptides with CDCA1-derived CTL-epitope sequences presented by HLA-A2 (A*02:01) or HLA-A24 (A*24:02) to select candidate CDCA1-LPs encompassing both Th cell epitopes and CTL-epitopes. We studied the immunogenicity of CDCA1-LPs and the cross-priming potential of LPs bearing CTL-epitopes in both human in vitro and HLA-class I transgenic mice in vivo. Then we analyzed the Th cell response to CDCA1 in head-and-neck cancer (HNC) patients before and after vaccination with a CDCA1-derived CTL-epitope peptide using IFN-γ enzyme-linked immunospot assays. We identified two CDCA1-LPs, CDCA1(39–64)-LP and CDCA1(55–78)-LP, which encompass naturally processed epitopes recognized by Th cells and CTLs. CDCA1-specific CTLs were induced through cross-presentation of CDCA1-LPs in vitro and in vivo. In addition, CDCA1-specific Th cells enhanced induction of CDCA1-specific CTLs. Furthermore, significant frequencies of CDCA1-specific Th cell responses were detected after short-term in vitro stimulation of peripheral blood mononuclear cells (PBMCs) with CDCA1-LPs in HNC patients (CDCA1(39–64)-LP, 74%; CDCA1(55–78)-LP, 68%), but not in healthy donors. These are the first results demonstrating the presence of CDCA1-specific Th cell responses in HNC patients and underline the possible utility of CDCA1-LPs for propagation of both CDCA1-specific Th cells and CTLs.
International Journal of Cancer 01/2014; 134(2):352-66. · 6.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We herein report the identification of an HLA-A2 supertype-restricted epitope peptide derived from hypoxia-inducible protein 2 (HIG2), which is known to be a diagnostic marker and a potential therapeutic target for renal cell carcinoma. Among several candidate peptides predicted by the HLA-binding prediction algorithm, HIG2-9-4 peptide (VLNLYLLGV) was able to effectively induce peptide-specific cytotoxic T lymphocytes (CTLs). The established HIG2-9-4 peptide-specific CTL clone produced interferon-γ (IFN-γ) in response to HIG2-9-4 peptide-pulsed HLA-A*02:01-positive cells, as well as to cells in which HLA-A*02:01 and HIG2 were exogenously introduced. Moreover, the HIG2-9-4 peptide-specific CTL clone exerted cytotoxic activity against HIG2-expressing HLA-A*02:01-positive renal cancer cells, thus suggesting that the HIG2-9-4 peptide is naturally presented on HLA-A*02:01 of HIG-2-expressing cancer cells and is recognized by CTLs. Furthermore, we found that the HIG2-9-4 peptide could also induce CTLs under HLA-A*02:06 restriction. Taken together, these findings indicate that the HIG2-9-4 peptide is a novel HLA-A2 supertype-restricted epitope peptide that could be useful for peptide-based immunotherapy against cancer cells with HIG2 expression.
PLoS ONE 01/2014; 9(1):e85267. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: PURPOSE: To identify long peptides (LPs) derived from a novel tumor-associated antigen (TAA), kinesin family member 20A (KIF20A), which induce tumor-specific T-helper type 1 (Th1) cells and CTLs. EXPERIMENTAL DESIGN: We combined information from a recently developed computer algorithm predicting HLA class II-binding peptides with KIF20A-derived CTL-epitope sequences presented by HLA-A2 (A*02:01) or HLA-A24 (A*24:02) to select candidate promiscuous Th1 cell epitopes containing CTL-epitopes. Peripheral blood mononuclear cells (PBMC) derived from healthy donors or patients with head-and-neck malignant tumor (HNMT) were used to study the immunogenicity of KIF20A-LPs, and the in vitro cross-priming potential of KIF20A-LPs bearing CTL-epitopes. We used HLA-A24 transgenic mice to address whether vaccination with KIF20A-LP induces efficient cross-priming of CTLs in vivo. The Th1 cell response to KIF20A-LPs in HNMT patients receiving immunotherapy with TAA-derived CTL-epitope peptides was analyzed using IFN-γ enzyme-linked immunospot assays. RESULTS: We identified promiscuous KIF20A-LPs bearing naturally processed epitopes recognized by CD4(+) T-cells and CTLs. KIF20A-specific CTLs were induced by vaccination with a KIF20A-LP in vivo. KIF20A expression was detected in 55% of HNMT by immunohistochemistry, and significant frequencies of KIF20A-specific Th1 cell responses were detected after short-term in vitro stimulation of PBMCs with KIF20A-LPs in 50% of HNMT patients, but not in healthy donors. Furthermore, these responses were associated with KIF20A expression in HNMT tissues. CONCLUSIONS: These are the first results demonstrating the presence of KIF20A-specific Th1 cell responses in HNMT patients and underline the possible utility of KIF20A-LPs for propagation of Th1 cells and CTLs.
Clinical Cancer Research 05/2013; · 8.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: OTS11101 is a novel peptide vaccine that acts as an angiogenesis inhibitor by inducing cytotoxic T lymphocyte (CTL) cells that specifically target vascular endothelial cells expressing vascular endothelial growth factor (VEGF) receptor 1. We conducted a phase I study to evaluate the safety, tolerability, maximum tolerated dose, and pharmacodynamic biomarker status of this vaccine. Nine patients with advanced solid tumors received 1.0 mg, 2.0 mg, or 3.0 mg of OTS11101 subcutaneously, once a week in a 28-day cycle. Three patients experienced grade 1 injection site reactions, which were the most frequent adverse events. Grade 2 proteinuria and hypertension each occurred in one patient. As other toxicities were generally mild, the maximum tolerated dose was not reached. Furthermore, we explored the induction of specific activated CTLs, and biomarkers related to angiogenesis. A pharmacodynamics study revealed that induction of specific CTLs was observed for a dose of 2.0 and 3.0 mg. The serum concentrations of soluble VEGF receptor 1 and 2 after vaccination increased significantly compared with baseline. A microarray was performed to give a comprehensive analysis of gene expression, suggesting that OTS11101 vaccination resulted in T cell activation in a clinical setting. In conclusion, OTS11101 was well tolerated in patients up to 3.0 mg once weekly and our biomarker analysis suggested that this anti-angiogenesis vaccine is biologically active.
[Show abstract][Hide abstract] ABSTRACT: Targeting of tumor angiogenesis with vaccines is a potentially valuable approach to cancer treatment. Elpamotide is an immunogenic peptide derived from vascular endothelial growth factor receptor 2, which is expressed at a high level in vascular endothelial cells. We have now carried out a phase I study to evaluate safety, the maximum tolerated dose, and potential pharmacodynamic biomarkers for this vaccine. Ten HLA-A*24:02-positive patients with advanced refractory solid tumors received elpamotide s.c. at dose levels of 0.5, 1.0, or 2.0 mg once a week on a 28-day cycle. Five patients experienced an injection site reaction of grade 1 and 2, which was the most frequent adverse event. In the 1.0 mg cohort, one patient experienced proteinuria of grade 1 and another patient developed both hypertension and proteinuria of grade 1. No adverse events of grade 3 or higher were observed, and the maximum tolerated dose was therefore not achieved. The serum concentration of soluble vascular endothelial growth factor receptor 2 decreased significantly after elpamotide vaccination. Microarray analysis of gene expression in PBMCs indicated that several pathways related to T cell function and angiogenesis were affected by elpamotide vaccination, supporting the notion that this peptide induces an immune response that targets angiogenesis in the clinical setting. In conclusion, elpamotide is well tolerated and our biomarker analysis indicates that this anti-angiogenic vaccine is biologically active. Clinical trial registration no. UMIN000008336.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the safety and efficacy of vaccination with human leukocyte antigen (HLA)-A24-restricted human vascular endothelial growth factor receptor 1 (VEGFR1)-1084 and VEGFR2-169 combined with chemotherapy in patients with advanced gastric cancer. HLA-A*2402-positive patients with advanced or recurrent adenocarcinoma of the stomach were vaccinated with VEGFR1-1084 and VEGFR2-169 combined with S-1 and cisplatin. The study included 22 patients (median age 60.5 years) who received at least one cycle of the combination therapy. No severe adverse effects caused by the vaccine therapy were observed except for an inflammatory reaction at the site of injection in 6 patients. Twelve patients (55%) showed partial response and 10 had stable disease after two cycles of the combination therapy. The disease control rate (partial response and stable disease) was 100% after two cycles. The median time to progression was 9.6 months and median overall survival was 14.2 months. VEGFR1-1084-specific cytotoxic T lymphocyte (CTL) response was induced in 18 (82%) of the 22 patients and VEGFR2-169-specific CTL response was induced in 18 (82%) of the 22 patients. Patients showing CTL response to VEGFR2-169 peptide had significantly better prognosis than those without, as demonstrated by the overall survival (OS) and time to progression (TTP) (OS, p=0.028, TTP, p=0.006). The combination therapy was well tolerated and highly effective in advanced or recurrent gastric cancer. Substantial specific CTL for both peptides was frequently induced even under chemotherapy. Thus, cancer vaccination combined with standard chemotherapy warrants further analysis as a promising strategy for the treatment of advanced cancer.
International Journal of Oncology 07/2012; · 2.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Since a phase I clinical trial using three HLA-A24-binding peptides from TTK protein kinase (TTK), lymphocyte antigen-6 complex locus K (LY6K), and insulin-like growth factor-II mRNA binding protein-3 (IMP3) had been shown to be promising for esophageal squamous cell carcinoma (ESCC), we further performed a multicenter, non-randomized phase II clinical trial.
Sixty ESCC patients were enrolled to evaluate OS, PFS, immunological response employing ELISPOT and pentamer assays. Each of the three peptides was administered with IFA weekly. All patients received the vaccination without knowing an HLA-A type, and the HLA types were key-opened at the analysis point. Hence, the endpoints were set to evaluate differences between HLA-A*2402-positive (24(+)) and -negative (24(-)) groups.
The OS in the 24 (+) group (n = 35) tended to be better than that in the 24(-) group (n = 25) (MST 4.6 vs. 2.6 month, respectively, p = 0.121), although the difference was not statistically significant. However, the PFS in the 24(+) group was significantly better than that in the 24(-) group (p = 0.032). In the 24(+) group, ELISPOT assay indicated that the LY6K-, TTK-, and IMP3-specific CTL responses were observed after the vaccination in 63%, 45%, and 60% of the 24(+) group, respectively. The patients having LY6K-, TTK-, and IMP3-specific CTL responses revealed the better OS than those not having CTL induction, respectively. The patients showing the CTL induction for multiple peptides have better clinical responses.
The immune response induced by the vaccination could make the prognosis better for advanced ESCC patients.
ClinicalTrials.gov, number NCT00995358.
Journal of Translational Medicine 07/2012; 10:141. · 3.99 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The field of cancer vaccine therapy is currently expected to become the fourth option in the treatment of cancer after surgery, chemotherapy and radiation therapy. We developed a novel cancer peptide vaccine therapy for bladder cancer through a genome-wide expression profile analysis.
Among a number of oncoproteins that are transactivated in cancer cells, we focused on M phase phosphoprotein 1 and DEP domain containing 1, both of which are cancer-testis antigens playing critical roles in the growth of bladder cancer cells, as candidate molecules for the development of drugs for bladder cancer. In an attempt to identify the peptide epitope from these oncoantigens, we conducted a clinical trial using these peptides for patients with advanced bladder cancer.
We identified HLA-A24-restricted peptide epitopes corresponding to parts of M phase phosphoprotein 1 and DEP domain containing 1 proteins, which could induce peptide-specific cytotoxic T lymphocytes. Using these peptides, we found that M phase phosphoprotein 1- and DEP domain containing 1-derived peptide vaccines could be well tolerated without any serious adverse events, and effectively induced peptide-specific cytotoxic T lymphocytes in vivo.
The novel approach adopted in the treatment with peptide vaccines is considered to be a promising therapy for bladder cancer.
Japanese Journal of Clinical Oncology 05/2012; 42(7):591-600. · 1.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cloning techniques to identify genes and peptides of tumor-associated antigens have created new possibilities for the immunotherapy of patients with advanced cancer. Here, we review recent clinical trials of specific cancer vaccines, mainly HLA-restricted peptides, and epitope-encoding vectors for advanced colorectal cancer (CRC). Many researchers initially focused on carcinoembryonic antigen (CEA) as an immunologic target antigen that is overexpressed on virtually all CRCs. A recombinant vaccine containing the CEA gene and dendritic cells (DCs) loaded with CEA peptide was administered to patients with CEA-elevated CRC. Although CEA-specific responses were detected, the clinical responses were limited. Recently, new types of clinical trials--namely, a personalized protocol to take into account the immunological diversity of cytotoxic T cell responses among patients and a novel cancer-testis antigen protocol that uses multiple peptides derived from genes identified by the cDNA array method--have been introduced. The personalized protocol seemed to be better than the classical (non-personalized) protocol in terms of clinical response and survival. Novel cancer-testis antigen protocols that use multiple CRC-derived peptides were recently conducted in patients with advanced CRC. The preliminary study yielded promising results regarding specific T cell responses to peptides and survival benefits. In this review, we summarize these results and discuss future perspectives.
Current pharmaceutical biotechnology 02/2012; 13(8):1439-45. · 3.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We examined the possible efficacy of the yttrium-90 ((90)Y)-labeled anti-CDH3/P-cadherin mouse monoclonal antibody (MAb-6) in radioimmunotherapy (RIT) for lung and colorectal cancers that express CDH3/P-cadherin.
MAb-6 was established using genetic immunization. The biodistribution of MAb-6 in nude mice with lung and colorectal cancers was examined by administering indium-111((111)In)-labeled MAb-6 to mice. The mice were prepared by inoculation of CDH3/P-cadherin-positive (EBC1, H1373, and SW948) and CDH3/P-cadherin-negative (A549 and RKO) tumor cells. Therapeutic effects and toxicity were investigated by administration of (90)Y-labeled MAb-6 ((90)Y-MAb-6) to EBC, H1373, and SW948-inoculated mice.
Our in vivo results confirmed the specific binding of MAb-6 to tumor cells after intravenous injections of (111)In-labeled MAb-6 to mice with tumors expressing CDH3/P-cadherin. A single intravenous injection of (90)Y-MAb-6 (100 μCi) significantly suppressed tumor growth in mice with tumors expressing CDH3/P-cadherin. Furthermore, two injections of (90)Y-MAb-6 led to complete tumor regression in H1373-inoculated mice without any detectable toxicity.
Our findings demonstrate that CDH3/P-cadherin-targeting RIT with (90)Y-MAb-6 is a promising strategy for the treatment for cancers expressing CDH3/P-cadherin.
Cancer Immunology and Immunotherapy 01/2012; 61(8):1211-20. · 3.64 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We here identified human leukocyte antigen-(HLA-)A(∗)2402-restricted epitope peptides from Cadherin 3, type 1, P-cadherin (CDH3) and kinesin family member 20A (KIF20A) that were found to be specifically expressed in cancer cells through genome-wide expression profile analysis. CDH3-10-807 peptide and KIF20A-10-66 peptide successfully induced specific CTL clones, and these selectively responded to COS7 cells expressing both HLA-A(∗)2402 and respective protein while did not respond to parental cells or COS7 cells expressing either HLA-A(∗)2402 or respective protein. Furthermore, CTL clones responded to cancer cells that endogenously express HLA-A(∗)2402 and respective protein, suggesting that CDH3-10-807 peptide and KIF20A-10-66 peptide are naturally presented on HLA-A(∗)2402 molecule of human cancer cells. Our results demonstrated that CDH3-10-807 peptide and KIF20A-10-66 peptide are novel HLA-A24-restricted tumor-associated antigens and would be applicable for CTL-inducing cancer therapies.
BioMed Research International 01/2012; 2012:848042. · 2.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The present study attempted to identify a useful tumor-associated antigen (TAA) for lung cancer immunotherapy and potential immunogenic peptides derived from the TAA. We focused on cell division cycle 45-like (CDC45L), which has a critical role in the initiation and elongation steps of DNA replication, as a novel candidate TAA for immunotherapy based on a genome-wide cDNA microarray analysis of lung cancer. The CDC45L was overexpressed in the majority of lung cancer tissues, but not in the adjacent non-cancerous tissues or in many normal adult tissues. We examined the in vitro and in vivo anti-tumor effects of cytotoxic T-lymphocytes (CTL) specific to CDC45L-derived peptides induced from HLA-A24 (A*24:02)-positive donors. We identified three CDC45L-derived peptides that could reproducibly induce CDC45L-specific and HLA-A24-restricted CTL from both healthy donors and lung cancer patients. The CTL could effectively lyse lung cancer cells that endogenously expressed both CDC45L and HLA-A24. In addition, we found that CDC45L (556) KFLDALISL(564) was eminent in that it induced not only HLA-A24 but also HLA-A2 (A*02:01)-restricted antigen specific CTL. Furthermore, the adoptive transfer of the CDC45L-specific CTL inhibited the growth of human cancer cells engrafted into immunocompromised mice. These results suggest that these three CDC45L-derived peptides are highly immunogenic epitopes and CDC45L is a novel TAA that might be a useful target for lung cancer immunotherapy.
Cancer Science 04/2011; 102(4):697-705. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Identification of tumour-associated antigens (TAAs) that induce cytotoxic T lymphocytes (CTLs) specific to cancer cells is critical for the development of anticancer immunotherapy. In this study, we aimed at identifying a novel TAA of pancreatic cancer for immunotherapy.
On the basis of the genome-wide cDNA microarray analysis, we focused on KIF20A (also known as RAB6KIFL/MKlp2) as a candidate TAA in pancreatic cancer cells. The HLA-A2 (A*02:01)-restricted CTL epitopes of KIF20A were identified using HLA-A2 transgenic mice (Tgm) and the peptides were examined to check whether they could generate human CTLs exhibiting cytotoxic responses against KIF20A(+), HLA-A2(+) tumour cells in vitro.
KIF20A was overexpressed in pancreatic cancer and in some other malignancies, but not in their non-cancerous counterparts and many normal adult tissues. We found that KIF20A-2 (p12-20, LLSDDDVVV), KIF20A-8 (p809-817, CIAEQYHTV), and KIF20A-28 (p284-293, AQPDTAPLPV) peptides could induce HLA-A2-restricted CTLs in HLA-A2 Tgm without causing autoimmunity. Peptide-reactive human CTLs were generated from peripheral blood mononuclear cells of HLA-A2(+) healthy donors by in vitro stimulation with the three peptides, and those CTLs successfully exhibited cytotoxic responses to cancer cells expressing both KIF20A and HLA-A2.
KIF20A is a novel promising candidate for anticancer immunotherapeutic target for pancreatic cancers.
British Journal of Cancer 01/2011; 104(2):300-7. · 5.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To establish efficient anticancer immunotherary, it is important to identify tumor-associated antigens (TAAs) directing the immune system to attack cancer. A genome-wide cDNA microarray analysis identified that secreted protein acidic and rich in cysteine (SPARC) gene is overexpressed in the gastric, pancreatic and colorectal cancer tissues but not in their noncancerous counterparts. This study attempted to identify HLA-A24 (A*2402)-restricted and SPARC-derived CTL epitopes. We previously identified H-2K(d)-restricted and SPARC-derived CTL epitope peptides in BALB/c mice, of which H-2K(d)-binding peptide motif is comparable with that of HLA-A24 binding peptides. By using these peptides, we tried to induce HLA-A24 (A*2402)-restricted and SPARC-reactive human CTLs and demonstrated an antitumor immune response. The SPARC-A24-1(143-151) (DYIGPCKYI) and SPARC-A24-4(225-234) (MYIFPVHWQF) peptides-reactive CTLs were successfully induced from peripheral blood mononuclear cells by in vitro stimulation with these two peptides in HLA-A24 (A*2402) positive healthy donors and cancer patients, and these CTLs exhibited cytotoxicity specific to cancer cells expressing both SPARC and HLA-A24 (A*2402). Furthermore, the adoptive transfer of the SPARC-specific CTLs could inhibit the tumor growth in nonobese diabetic/severe combined immunodeficient mice bearing human cancer cells expressing both HLA-A24 (A*2402) and SPARC. These findings suggest that SPARC is a potentially useful target candidate for cancer immunotherapy.
International Journal of Cancer 09/2010; 127(6):1393-403. · 6.20 Impact Factor