Modulated electro-hyperthermia enhances dendritic cell therapy through an abscopal effect in mice.

The aim of this study was to assess whether modulated electro-hyperthermia (mEHT) can induce an abscopal effect and thereby enhance the antitumor effects of immunotherapy. We used an intratumoral dendritic cell (DC) injection and mEHT to treat C3H/He mice inoculated with squamous cell carcinoma SCCVII cells in the left leg, and we assessed the whole body antitumor effects. Tumors were examined every two or three days in order to assess growth inhibition. The tumor-draining lymph nodes were removed to enable flow cytometric analysis of CD3+ and CD8+ cells, whereas immunohistochemistry was used to assess CD8, S100 and Foxp3 expression in the tumors. Additionally, GP96 expression in the tumors from the different treatment groups was measured. In the control group, the mean tumor volume was larger than that in other groups. These results indicated that the combination therapy of an intratumoral DC injection and mEHT evoked systemic antitumor activity. A larger number of CD3+ and CD8+ cells were detected by flow cytometric analysis in the DC plus mEHT treatment group. Tumor tissue immunostaining showed that CD8 and S100 were more strongly expressed in the DC plus mEHT treatment group, although Foxp3 expression was much higher in the control group. The GP96 gene expression level in the mEHT group was significantly different from the expression level in the control group. An abscopal effect may be induced by mEHT, and the effect of immunotherapy with DCs was strongly enhanced by the overexpression of GP96. GP96 is thought to be one of the molecules explaining the abscopal effect. Direct intratumoral administration of DCs and mEHT may be a feasible future treatment strategy.

A COX-2 inhibitor enhances the antitumor effects of chemotherapy and radiotherapy for esophageal squamous cell carcinoma.

Cyclooxygenase-2 (COX-2) is a key enzyme of prostaglandin (PG) synthesis that has been demonstrated to be overexpressed in several types of cancers. The function of COX-2 in tumor progression has been recently elucidated. In tumors in which COX-2 is overexpressed, the antitumor effects are suppressed. We examined the effects of celecoxib, a COX-2 inhibitor, in enhancing the antitumor effects of chemotherapy and radiotherapy for esophageal squamous cell carcinoma (ESCC) by reducing the COX-2 activity. We used the human esophageal squamous cell lines TE2 and T.Tn treated with celecoxib and 5-FU/radiation, after which cell viability assays were performed. Changes in the expressions of dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyl transferase (OPRT) mRNA and PGE2 were also measured. In addition, apoptotic changes, and the invasion and migration activity in both the celecoxib and 5-FU treated cells were evaluated. The experiments showed that T.Tn and TE2 proliferation was strongly inhibited by the combination of 5-FU/radiation and the COX-2 inhibitor. Inhibiting the COX-2 activity induced a reduction in PGE2 levels in TE2/T.Tn cells. Following treatment with the COX-2 inhibitor and 5-FU, the OPRT expression was upregulated and the DPD expression was downregulated in the resistant cells. In addition, the combination treatment with the COX-2 inhibitor and 5-FU markedly inhibited both the cell invasion and migration activity. Therefore, COX-2 inhibitors can be useful enhancers of antitumor drugs and radiotherapy for ESCC.

COX2 expression predicts resistance to chemoradiotherapy in esophageal squamous cell carcinoma.

PURPOSE: The overexpression of cyclooxygenase (COX)2 is correlated with carcinogenesis, tumor progression, and prognosis, and increased COX2 expression is correlated with radiation resistance. However, no correlation between the COX2 expression and resistance to chemoradiotherapy for esophageal squamous cell carcinoma has been characterized. The purpose of the present study was to evaluate whether COX2 expression is an indicator of resistance to chemoradiotherapy in esophageal squamous cell carcinoma and the feasibility of COX2 as a biomarker for CRT. METHODS: Fifty-eight patients who were diagnosed with esophageal squamous cell carcinoma from biopsy samples were enrolled in the present series. All patients underwent concurrent chemoradiotherapy in a neoadjuvant setting, followed by radical esophagectomy. COX2 expression was evaluated by immunohistochemical staining and statistically compared with the histopathologic findings in surgically resected specimens. RESULTS: The rate of responders was 87% for weak expression of COX2, 62% for moderate expression, and 30% for strong expression, and there was a close correlation between COX2 expression and the response rate (Kendall's τb = 0.396, P = 0.001). In the univariate analysis, negative or weak expression of COX2 was found to correlate significantly with CRT response (odds ratio, 6.296; 95% confidence interval (CI), 1.58-25.096; P = 0.010). In the multivariate analysis, weak expression of COX2 (30% or less) was found to be an independent prognostic factor (odds ratio, 6.534; 95% CI, 1.535-27.803; P = 0.011). CONCLUSIONS: The COX2 expression predicts resistance to chemoradiotherapy in esophageal squamous cell carcinoma, and it also is a feasible biomarker for evaluating the CRT response.

Correlation between gp96 expression and the surgical outcome in patients with esophageal squamous cell carcinoma.

BACKGROUND: Heat-shock protein gp96 plays an important role in antitumor immunoreactions. Gp96 has a close relationship with antitumor immunity. This study evaluated the correlation between gp96 expression and the prognosis in esophageal squamous cell carcinoma. METHODS: Seventy-eight patients with primarily resected esophageal squamous cell carcinoma were enrolled onto this study, and gp96 expression was evaluated by immunohistochemical staining. The association of clinicopathological factors and patients' survival was calculated by univariate (log rank test) and multivariate (Cox proportional hazard regression method) analyses. RESULTS: Fifty-seven (73%) of 78 cases were gp96 positive, and 21 were negative (27%). The survival of patients with gp96-negative disease was significantly shorter (5-year survival, 22.9 months) than with gp96-positive disease (45.8 months; P = 0.049), and the multivariate analysis showed that gp96 negativity is an independent risk factor for poor survival (hazard ratio, 2.577; P = 0.040). Gp96-negative cases had more metastatic lymph nodes than did negative cases, especially in T1 cases (4.8 in gp96-negative cases vs. 0.84 in gp96-positive cases; P = 0.064) CONCLUSIONS: The downregulation of gp96 expression is closely correlated with poor survival in esophageal squamous cell carcinoma.