Kouichirou Tahara

A MAGE‐1‐encoded HLA‐A24‐binding synthetic peptide induces specific anti‐tumor cytotoxic T lymphocytes

Although several MAGE‐1 peptides have already been identified, the MAGE‐1‐encoded peptide presented by HLA‐A24, which is the most common allele in Japanese population and is also frequently present in Caucasians, might have a wide applicability for immunotherapy using these peptides. To identify this potential peptide, we examined the induction of specific cytotoxic T lymphocytes (CTL) from the peripheral‐blood mononuclear cells (PBMC) in HLA‐A24 healthy donors by in vitro stimulation with MAGE‐1‐encoded synthetic peptides with a binding affinity for HLA‐A24, by a simplified method. Of the 5 peptides tested, the highest HLA binder (NYKHCFPEI) was able to elicit CTL from unseparated PBMC by stimulation with freshly isolated, peptide‐pulsed PMBC as antigen‐presenting cells (APC) and by also using interleukin 7 and keyhole‐limpet hemocyanin for a primary culture. The induced CTL could thus lyse HLA‐A24 tumor cells expressing MAGE‐1, as well as the peptide‐pulsed target cells, in an HLA‐class‐I‐restricted manner. By using the MAGE‐1/HLA‐A24 peptide, NYKHCFPEI, we found it possible to immunize many more patients, especially Japanese patients, by means of such peptide‐based immunotherapeutic approaches to MAGE‐1‐positive malignant tumors. Int. J. Cancer 80:169–172, 1999.

Immunoactivative role of indoleamine 2,3-dioxygenase in human hepatocellular carcinoma.

Background:  Indoleamine 2,3‐dioxygenase (IDO) is a tryptophan catabolic enzyme. Recent studies have focused on the immunoregulatory role of IDO in mononuclear cells. The role of IDO in hepatocellular carcinoma (HCC) cell lines and HCC patients was examined.

Clinicopathologic significance of KIAA1199 overexpression in human gastric cancer.

BackgroundKIAA1199 is an inner-ear-specific gene which encodes KIAA1199 protein, the function of which is unknown. KIAA1199 might be a novel, positively regulated target of Wnt signaling. The aim of this study was to examine the expression of KIAA1199 in surgical specimens of gastric cancer to evaluate the clinical outcome.MethodsThe expression of KIAA1199 mRNA was studied by semiquantitative reverse-transcription polymerase chain reaction (RT-PCR), and the expression status was analyzed from the viewpoint of clinical and pathological factors. Univariate and multivariate analyses were performed. In addition, an immunohistochemical study was performed in the selected samples.ResultsA significantly higher expression of KIAA1199 messenger RNA (mRNA) was recognized in tumor tissue compared with that of paired normal tissues (P < 0.01). The cases were divided into high- (n = 39) and low-expression (n = 71) groups according to KIAA1199 expression status in the tumor. The overall 5-year survival rate was significantly better in the KIAA1199 low-expression group (61.2%) than in the high-expression group (29.6%) (P < 0.05). Clinicopathological factors such as well and moderately tumor differentiation, positive lymph node metastasis, positive distant metastases, and positive peritoneal dissemination were more frequently observed in the high-expression group than in the low-expression group (P = 0.02, 0.08, 0.01, and 0.03, respectively). KIAA1199 expression was an independent prognostic factor (P = 0.03).ConclusionsKIAA1199 was highly expressed in gastric cancer, and was associated with prognosis and lymph node metastasis in multivariate analyses. Taken together, KIAA1199 may be a novel gene that plays an important role in progression of gastric cancer.

Microwave coagulation therapy accelerates growth of cancer in rat liver

BACKGROUND/AIMS Although microwave coagulation therapy (MCT) has been performed for liver cancer, there has been no report examining the influence of this therapy on the growth of possible remnant cancer. METHODS A solid cube of AH-130 cells (ascites hepatoma cell line) was implanted into the left lateral lobe of the rat liver. Five days later, MCT was applied to the middle liver lobe of these rats. Tumor growth and cytokine levels in plasma and the liver were compared between rats that underwent MCT and rats that did not. RESULTS The mean tumor weight in the MCT group (222.6+/-51.5 mg, mean+/-SD) was significantly greater than that in the control group (126.7+/-19.7 mg, P<0.01) at postoperative day (POD) 5. Immunohistochemistry for anti-proliferating cell nuclear antigen showed the labeling index in the MCT group (90.4%) to be higher than that in the control group (76.7%, P<0.01). Liver basic fibroblast growth factor and transforming growth factor-beta 1 levels in the MCT group on POD 3 were significantly higher than levels in the control group. CONCLUSIONS The present study suggests the clinically important finding that MCT accelerates the growth of small residual tumors in the liver.

Clinical significance of low expression of Prostasin mRNA in human gastric cancer

Prostasin is considered to have suppressive activities against tumor progression. The aim of this study was to clarify its clinical significance in gastric cancer.

Antitumor and antivascular effects of AC-7700, a combretastatin A-4 derivative, against rat liver cancer

AbstractBackground. Unlike the many chemotherapeutic agents that do not effectively stop blood flow or induce necrosis in hepatocellular carcinoma, AC-7700 has been shown to inhibit tubulin polymerization and selectively stop tumor blood flow. The aim of this study was to elucidate the antivascular and antitumor effects of AC-7700 on rat hepatoma. Methods. AH-130 cells, a rat hepatoma cell line, were solidified and implanted into the liver of Donryu rats. Vascularity of the liver tumor was directly identified by in-vivo fluorescence microscopy from 0 to 60 min after the injection of 10 mg/kg AC-7700. To observe the antivascular effect of AC-7700, the vascular density of the tumor was measured and assessed as the ratio of preinjection to postinjection values. The antitumor effects were evaluated with histopathologic findings and analysis of animal survival. Results. In-vivo microscopic observation showed that tumor perfusion diminished within 30 min after AC-7700 administration. Vascular density in the AC-7700 group was significantly less than that in the control group at 60 min (AC-7700, 26.3 ± 16.4%; control, 88.5 ± 9.2%; P < 0.001). After AC-7700 injection, marked necrosis of tumor cells was observed histologically, and tumor area was decreased significantly (AC-7700, 11.5 ± 15.4 mm2; control, 43.5 ± 18.3 mm2; P < 0.05). The survival rate (50%) of the AC-7700 group animals was better than that of the control group (0%; P < 0.01). Conclusion. Markedly decreased tumor perfusion was induced by AC-7700 within 30 min, and this decrease may have contributed to the tumor necrosis and favorable outcome in the treatment group. AC-7700 appears to be a promising agent for the treatment of hepatocellular carcinoma.

Generation of specific antitumor reactivity by the stimulation of spleen cells from gastric cancer patients with MAGE-3 synthetic peptide.

Abstract The induction of cytotoxic T lymphocytes (CTL) from peripheral blood mononuclear cells (PBMC) using MAGE peptide has been investigated in order to use MAGE antigens immunotherapeutically. We therefore developed a simplified method for inducing peptide-specific CTL that kill tumor cells expressing MAGE from the PBMC of either healthy donors or even cancer patients. Since the spleen is a major lymphoid organ, we used a simple method to examine the capacity of spleen cells to generate MAGE-specific CTL by in vitro stimulation with MAGE peptide in gastric cancer patients. The CTL responses could thus be induced from unseparated spleen cells in HLA-A2 patients with gastric carcinoma expressing MAGE-3 by stimulating these cells with autologous spleen cells pulsed with HLA-A2-restricted MAGE-3 peptide as antigen-presenting cells and by using keyhole limpet hemocyanin and interleukin-7 for the primary culture. The induced CTL were thus able to lyse HLA-A2-positive carcinoma cells transfected with MAGE-3 and expressing MAGE-3, as well as the target cells pulsed with the peptide, in an HLA-class-I or -A2-restricted manner. Since MAGE-specific CTL could be induced from the spleen cells of gastric cancer patients, the spleen appears to play an important role in either clinical tumor vaccination or the treatment of cancer patients by adoptive immunotherapeutic approaches using the MAGE peptide.

Prognostic implication of p53 protein expression in relation to nuclear pleomorphism and the MIB-1 counts in breast cancer

BackgroundA close correlation of the p53 protein expression to nuclear pleomorphism and proliferative activity in breast cancer has been reported. The prognostic implications of p53 protein expression, however, in relation to nuclear pleomorphism and proliferative activity in breast cancer remain controversial.Patients and MethodsNuclear pleomorphism and immunohistochemical reactivity for p53 protein and MIB-1 were evaluated on formalin-fixed paraffin-stored sections from 250 patients with breast cancer for whom the median follow-up duration was 6.4 years.Resultsp53 protein expression was positive in 66 (26.4%) of 250 cases. Nuclear pleomorphism was grade I or II in 169 (67.6%) cases and grade I in 81 (32.4%) cases. The MIB-1 counts were more than 10% in 102 (40.8%) cases and less than 10% in 148 (59.2%) cases. There was a close correlation between p53 protein expression and nuclear pleomorphism (p < 0.0001) and between p53 protein expression and MIB-1 counts (p < 0.0001). Univariate analyses showed the 66 cases with positive p53 protein expression to have a significantly (p = 0.0284) worse disease free survival (DFS) than the 184 cases with negative p53 protein expression. A multivariate analysis, however, on the variables including all of p53 protein expression, nuclear pleomorphism and MIB-1 counts indicated the MIB-1 counts (p = 0.0041) as well as the lymph node status to be independently significant factors for DFS, while neither p53 protein expression nor nuclear pleomorphism were independently significant factors for DFS.ConclusionThe present study demonstrated that the p53 protein expression, nuclear pleomorphism and MIB-1 counts all demonstrated prognostic significance for breast cancer, while the most significant prognostic indicator among these three biological parameters was the MIB-1 counts.

Potent Stimuli Combined with Lipopolysaccaride and IFNγ May Improve Immunotherapy against HCC by Increasing the Maturation and Subsequent Immune Response of the Dendritic Cells

Dendritic cells (DCs)-based immunotherapy is a new strategy for cancer treatment and has been used in some clinical trials against cancer, including melanoma, and has shown promising results. However, the conventional protocol of DC immunotherapy may not be effective for hepatocellular carcinoma (HCC) because of impaired DC maturation in HCC patients. In order to induce sufficient maturation on HCC derived DCs, we tested various stimuli such as tumor necrosis factor (TNF) alpha, lipopolysaccharide (LPS), interferon (IFN)gamma and CD40-ligand. In stimulating with LPS + IFNgamma, DCs of HCC patients expressed significantly high levels of CD86 (p < 0.05) and produced high levels of IL-12 as compared to DCs stimulated with TNFalpha alone. Moreover, it showed better ability to stimulate allogeneic mixed lymphocyte reaction. It concluded that LPS and IFNgamma was the best combination of stimuli for induction of sufficient maturation on DCs derived from HCC.