Shigeru Yutani

Expression of the tumor-rejection antigen SART1 in brain tumors.

We have reported a tumor‐rejection antigen, SART1259, possessing tumor epitopes capable of inducing cytotoxic T lymphocytes (CTLs) in epithelial‐cancer patients. This study investigated the expression of SART1259 antigen in brain tumors, to explore for a potential molecule for use in specific immunotherapy of patients with brain tumors. The SART1259 antigen was detected in the cytosol fraction of 13 of 18 (72%) glioma cell lines and in 12 of 34 (35%) brain‐tumor tissues, with a higher rate of expression among malignant gliomas (5/10, 50%) and schwannomas (3/4). HLA‐A24‐restricted and SART1‐specific CTLs recognized the HLA‐A24+ and SART1259+ glioma cells, and the levels of recognition correlated both with HLA‐A24‐antigen expression level and with the concentration of the SART1 peptide antigen. Therefore, the SART1259 antigen could be a target molecule for specific immunotherapy of patients with brain tumors expressing HLA‐class‐I antigens. Int. J. Cancer 83:760–764, 1999.

A decrease in AFP level related to administration of interferon in patients with chronic hepatitis C and a high level of AFP

It is known that there is a very high incidence of hepatocellular carcinoma (HCC) among patients with type C chronic hepatitis and cirrhosis, and α -fetoprotein (AFP) has been widely used as a diagnostic marker for HCC. However, there are some patients showing continuous high AFP values but no evidence of HCC, and some studies have defined such patients as a high-risk group for HCC. In vitro study has shown that interferon (IFN) inhibits cell proliferation and enhances apoptosis as well as specific cytotoxic T lymphocytes against HCC, resulting in direct anticancer actions. In this study, we investigated the effect of IFN on AFP changes in chronic hepatitis C patients. Of 40 patients with chronic hepatitis C in whom diagnostic imaging confirmed the absence of HCC, 24 patients showed high pretreatment AFP values (high AFP group: AFP level > 10 ng/dl; mean ± SD, 46.3 ± 41.5 ng/dl) and 16 showed low pretreatment AFP values (low AFP group: pretreatment AFP level ≤ 10 ng/dl; mean ± SD, 5.3 ± 2.2 ng/dl). Pretreatment clinical parameters were statistically evaluated in relation to the AFP value. In the high AFP group, the platelet count, albumin level, and prothrombin (%) were significantly lower (P = 0.047, P = 0.0002, and P = 0.044, respectively), suggesting that AFP value increases with advancing liver disease. Subsequently 27 patients were administered IFN (IFN group), and the remaining 13 patients were administered Stronger Neo-minophagen C (SNMC), a glycyrrhizin preparation (SNMC group), as a control group receiving liver-protective therapy. Alanine aminotransferase was reduced in both the IFN and the SNMC group (mean, 132.56 to 60.07 mg/ml [P < 0001] and 147.85 to 56.23 mg/ml [P = 0.0240], respectively). AFP was significantly reduced in the IFN group (mean, 30.03 to 12.65 ng/ml; P = 0.0034), but there was no significant change in AFP in the SNMC group (mean, 29.70 to 39.17 ng/ml). AFP is useful for diagnosing HCC; however, some patients show a persistently high AFP level in the absence of HCC, and these patients have been described as a high-risk group for HCC. In this study, we found that IFN therapy but not SNMC universally reduced the AFP baseline. Since AFP is a significant predictor for HCC, therapeutic strategies for hepatitis C, e.g., long-term low-dose IFN treatment, may reduce hepatocarcinogenesis.

Assessment of immunological biomarkers in patients with advanced cancer treated by personalized peptide vaccination

To investigate immunological biomarkers to predict overall survival of advanced cancer patients under treatment with personalized peptide vaccination, correlations between overall survival and biomarkers, including cytotoxic T lymphocyte (CTL) and immunoglobulin G (IgG) responses to the vaccinated peptides, were investigated in 500 advanced cancer patients who received personalized peptide vaccination from October 2000 to October 2008. The best clinical response was assessed for in 436 patients, 43 patients (10%) had partial response, 144 patients (33%) had stable disease and 249 patients (57%) had progressive, with a median overall survival of 9.9 months. Both lymphocyte counts prior to the vaccination (P = 0.0095) and increased IgG response (P = 0.0116) to the vaccinated peptides, along with performance status (P < 0.0001), well correlated with overall survival. To confirm the superiority of IgG response to CTL response, the samples from advanced castration-resistant prostate cancer patients who survived more than 900 days (n=20) and those who died within 300 days (n=23) were analyzed further. As a result, both the numbers of peptides, to which increased IgG responses were observed, and the fold increases in IgG levels were significantly higher in long-term survivors (P = 0.000282 and P = 0.00045). In contrast, CTL responses were not statistically different between the two groups. Both lymphocyte numbers and IgG response were thus suggested to be biomarkers of cancer vaccine for advanced cancer patients.

Phase I clinical study of a peptide vaccination for hepatitis C virus‐infected patients with different human leukocyte antigen‐class I‐A alleles

Hepatitis C virus (HCV) infection has a high risk of liver cirrhosis and hepatocellular carcinoma at later stages. We recently identified a peptide derived from the HCV core protein capable of inducing both cellular and humoral responses to nearly all HCV‐positive patients in Japan with different human leukocyte antigen (HLA)‐class I‐A alleles. To assess the safety and immune responses to this novel peptide, we conducted a phase I dose‐escalation study of the vaccination for 26 HCV‐positive patients who were either non‐responders to the interferon‐based therapy (n = 23) or refused it (n = 3). The regimen was well tolerated, with no severe vaccine‐related toxicity. Twenty‐five and 22 patients completed the first and second cycle vaccination (6 and 12 vaccine injections), respectively. After a series of six vaccine injections, peptide‐specific CTL activity was augmented in peripheral blood mononuclear cells from 15 of 25 patient samples, with an expected optimal dose of 1 mg peptide. After 12 vaccine injections, peptide‐specific IgG production was augmented in plasma from the majority of patients (15 of 22 patients) tested, but not in a dose‐dependent fashion. There were two HCV RNA responders with >1 log declines. Among patients whose pre‐vaccination levels of alanine aminotransferase and alpha feto‐protein exceeded the normal ranges, a <30% decrease was found in 7 of 24 and three of six patients, respectively. Because of its tolerability and higher rate of immune boosting, this protocol is recommended for a phase II study to investigate its clinical efficacy. (Cancer Sci 2009; 100: 1935–1942)

Phase II Study of Personalized Peptide Vaccination for Previously Treated Advanced Colorectal Cancer

Kibe and colleagues report the safety and benefit in a phase II study of 60 pretreated, advanced colorectal cancer (CRC) patients of personalized vaccines comprising HLA-matched peptides selected from preexisting host immunity, providing a new approach of personalized immunotherapy for refractory CRC. The prognosis of advanced colorectal cancer (aCRC) remains poor, and development of new therapeutic approaches, including immunotherapy, is needed urgently. Herein we report on our phase II study of personalized peptide vaccination (PPV) in 60 previously treated patients with aCRC, who had failed at least one regimen of standard chemotherapy and/or targeted therapy. For PPV, a maximum of four HLA-matched peptides were individually selected from a pool of 31 different peptide candidates based on preexisting host immunity, and administered subcutaneously without severe adverse events. Boosting of IgG and cytotoxic T lymphocyte (CTL) responses specific to the administered peptides was observed in 49% and 63%, respectively, of the patients, who completed the first cycles of six vaccinations. Median overall survival (OS) time was 498 days, with 1- and 2-year survival rates of 53% and 22%, respectively. Multivariate Cox regression analysis of prevaccination factors showed that plasma IL6, IP-10, and BAFF levels were significantly prognostic for OS [hazard ratio (HR), 1.508, P = 0.043; HR, 1.579, P = 0.024; HR, 0.509, P = 0.002, respectively]. In addition, increased peptide-specific CTL responses after vaccination were significantly predictive of favorable OS (HR, 0.231; P = 0.021), suggesting a causal relationship between biologic and clinical efficacy of PPV. On the basis of the safety profile and potential clinical efficacy, we believe that clinical trials of PPV would be warranted for previously treated patients with aCRC. Cancer Immunol Res; 2(12); 1154–62. ©2014 AACR.

A phase II study of a personalized peptide vaccination for chemotherapy-resistant advanced pancreatic cancer patients

Pancreatic cancer is one of the most aggressive cancers with a median survival time (MST) of <6 months in chemotherapy-resistant patients. Therefore, the development of novel treatment modalities is needed. In the present study, a phase II study of personalized peptide vaccination (PPV) was conducted, in which vaccine antigens were selected and administered based on the pre-existing IgG responses to 31 different pooled peptides, for 41 chemotherapy-resistant advanced pancreatic cancer patients. No vaccine-related severe adverse events were observed. IgG responses specific to at least one of the vaccine peptides were augmented in 14 of 36 patients (39%) and in 18 of 19 patients (95%) tested after the 5th and 11th vaccination, respectively. MST from the first vaccination was 7.9 months with a 1-year survival rate of 26.8%. Higher serum amyloid A (SAA) and C-reactive protein (CRP) levels in pre-vaccination plasma were unfavorable factors for overall survival (OS). Due to the safety profile and the potential clinical efficacy, the conduction of additional clinical trials of PPV for chemotherapy-resistant advanced pancreatic cancer patients is warranted.

Expression of the SART3 tumor rejection antigen in renal cell carcinoma

PURPOSE We recently reported that SART3 tumor rejection antigen is recognized by HLA class I restricted cytotoxic T lymphocytes from patients with esophageal cancer. We now investigate the expression of SART3 antigen in renal cell carcinoma to identify an appropriate molecule that may be used in specific immunotherapy of renal cell carcinoma. MATERIALS AND METHODS Renal cell carcinoma and nontumorous kidney tissues were obtained at surgery. A section of each sample was minced with scissors and stored at -80C until use. SART3 antigen expression was examined in uncultured renal cell carcinoma and nontumorous kidney tissues. We also evaluated the ability of derived peptides to include cytotoxic T lymphocytes in peripheral blood mononuclear cells from patients with renal cell carcinoma. RESULTS The SART3 antigen was detected in all renal cell carcinoma cell lines, primary cultures of renal cell carcinoma and nontumorous kidney tissues, and in the cytosol of 57% and 15% of renal cell carcinoma and nontumorous kidney tissues, respectively. HLA-A2402 restricted and tumor specific cytotoxic T lymphocytes (KE4) used in cloning of the SART3 gene were significantly cytotoxic to cells from renal cell carcinoma cell lines and primary cultures of renal cell carcinoma tissue but they did not lyse normal cells, including those from primary cultures of nontumorous kidney tissue. The SART3 peptides derived from positions 109-118 and 315-323 induced HLA-A24 restricted cytotoxic T lymphocytes to renal cell carcinoma cells from peripheral blood mononuclear cells of patients with renal cell carcinoma. CONCLUSIONS The SART3 antigen and derived peptides may be applied to the specific immunotherapy of HLA-A24+ renal cell carcinoma.

Antibody Reactive to a Hepatitis C Virus (HCV)‐Derived Peptide Capable of Inducing HLA‐A2 Restricted Cytotoxic T Lymphocytes Is Detectable in a Majority of HCV‐Infected Individuals without HLA‐A2 Restriction

Hepatitis C virus (HCV) is a single‐strand RNA virus. Approximately 170 million people around the world are persistently infected and are at risk of liver cirrhosis or cancer. There is an urgent need to develop both therapeutic and diagnostic modalities of HCV. One approach to achieve these goals would be to determine highly immunodominant HCV peptides which are recognized by both cellular and humoral immunities. This study reports one such peptide, HCV‐core protein at positions 35–44, having HLA‐A2 binding motifs. IgG specific to this CTL‐epitope peptide is consistently detectable in a majority of the patients with HCV infection regardless of the different HLA types, different disease conditions, and different HCV‐genotypes tested. The sequence LPRR at positions 37–40 is considered to be the fine epitope recognized by the IgG. These results may provide new insights for the development of both therapeutic and diagnostic modalities of HCV at lower costs.

Radiofrequency ablation combined with transarterial chemoembolization for intermediate hepatocellular carcinoma

Radiofrequency ablation therapy (RFA) combined with transarterial chemoembolization (TACE) (combination therapy) is effective for early‐stage hepatocellular carcinoma (HCC). The aim of this study was to compare the long‐term effects of combination therapy with supportive care alone for intermediate HCC.

Humoral immune responses to CTL epitope peptides from tumor-associated antigens are widely detectable in humans: A new biomarker for overall survival of patients with malignant diseases

Both cellular and humoral immune responses are crucial to induce potent anti-tumor immunity, but most of currently conducted peptide-based cancer vaccines paid attention to cellular responses alone, and none of them are yet approved as a therapeutic modality against cancer patients. We investigated humoral immune responses to CTL epitope peptides derived from tumor-associated antigens in healthy donors and patients with various diseases to facilitate better understanding of their distribution patterns and potential roles. Bead-based multiplex assay, ELISA, and Western blotting were used to measure immunoglobulins reactive to each of 31 different CTL epitope peptides. Importantly, the sums of anti-peptide IgG levels specific to 31 CTL epitope peptides were well correlated with better overall survival (OS) in patients with malignant diseases. Our results suggested that humoral immune responses to CTL epitope peptides were widely detectable in humans. Measurement of immunoglobulins specific to CTL epitope peptides may provide a new biomarker for OS of patients with malignant diseases, although it still remains to be determined whether the correlations between humoral immune responses to epitope peptides and OS are observed only for the CTL epitopes used, or also for other panels of peptides. Quantity of circulating IgG reactive to these peptides was also discussed.