Dendritic cell-mediated cross-presentation of antigens derived from colon carcinoma cells exposed to a highly cytotoxic multidrug regimen with gemcitabine, oxaliplatin, 5-fluorouracil, and leucovorin, elicits a powerful human antigen-specific CTL response with antitumor activity in vitro

Chemotherapy enhances CD8(+) T cell-mediated antitumor immunity induced by vaccination with vaccinia virus

The use of immunotherapy or chemotherapy alone is generally ineffective against well-established tumors. To overcome this intrinsic resistance against therapy for tumors, we have attempted to combine immunotherapy with chemotherapy. In this study, we tried to induce a rapid antitumor effect via chemoimmunotherapy using a vaccinia viral vaccine as an immunotherapeutic agent with anticancer agents including epigallocatechin-3-gallate (EGCG) and conventional anticancer drugs. Although a combination of vaccinia-mediated vaccination and chemotherapy led to a strong inhibition of tumor growth, monotherapy alone failed to completely cure tumors. In contrast, intravenous injection of cisplatin (CDDP) or cyclophosphamide (CTX) after vaccinia virus vaccination led to complete regression of the established tumors. Interestingly, anticancer drugs appear to augment the antitumor effect of the vaccinia virus-mediated immunotherapy. This effect is mainly associated with the enhanced tumor-specific CD8(+) T cell immune response induced by vaccinia virus, which was demonstrated by antibody depletion. However, anticancer drugs alone failed to induce a significant enhancement of the tumor-specific CD8(+) T cell immune response. Taken together, these results suggest that combining vaccinia virus-based immunotherapy with anticancer drugs is particularly effective against established tumors by increasing the tumor antigen-specific CD8(+) T cell immune response, which is primed by vaccinia virus-mediated vaccination.

Epigallocatechin-3-gallate enhances CD8+ T cell-mediated antitumor immunity induced by DNA vaccination

Immunotherapy and chemotherapy are generally effective against small tumors in animal models of cancer. However, these treatment regimens are generally ineffective against large, bulky tumors. We have found that a multimodality treatment regimen using DNA vaccination in combination with chemotherapeutic agent epigallocatechin-3-gallate (EGCG), a compound found in green tea, is effective in inhibiting large tumor growth. EGCG was found to induce tumor cellular apoptosis in a dose-dependent manner. The combination of EGCG and DNA vaccination led to an enhanced tumor-specific T-cell immune response and enhanced antitumor effects, resulting in a higher cure rate than either immunotherapy or EGCG alone. In addition, combined DNA vaccination and oral EGCG treatment provided long-term antitumor protection in cured mice. Cured animals rejected a challenge of E7-expressing tumors, such as TC-1 and B16E7, but not a challenge of B16 7 weeks after the combined treatment, showing antigen-specific immune responses. These results suggest that multimodality treatment strategies, such as combining immunotherapy with a tumor-killing cancer drug, may be a more effective anticancer strategy than single-modality treatments.

Chemo-immunotherapy of metastatic colorectal carcinoma with gemcitabine plus FOLFOX 4 followed by subcutaneous granulocyte macrophage colony-stimulating factor and interleukin-2 induces strong immunologic and antitumor activity in metastatic colon cancer patients

PURPOSE

Tumor cell killing by anticancer drugs may be supported by their immuno- and pharmacologic effects. Chemotherapy is in fact able to (A) upregulate tumor-associated antigen expression, including carcinoembryonic antigen (CEA) or other target molecules such as thymidylate synthase (TS); and (B) downregulate tumor cell resistance to the death signals induced by tumor antigen-specific cytotoxic T lymphocytes. This provides the rationale for combining chemo- and immunotherapy.

MATERIALS AND METHODS

We describe the results of a translational phase II trial designed to evaluate the toxicity, antitumor activity and immunologic effects of gemcitabine + FOLFOX-4 (oxaliplatin, fluorouracil, and folinic acid) polychemotherapy followed by the subcutaneous administration of granulocyte macrophage colony-stimulating factor and low-dose interleukin-2 in colorectal carcinoma patients. The study involved 29 patients (16 males and 13 females with a mean age of 69 years), 21 of whom had received a previous line of treatment, and 19 had liver involvement.

RESULTS

The treatment was well tolerated and induced very high objective response (68.9%) and disease control rates (96.5%), with an average time to progression of 12.5 months. An immunologic study of peripheral blood mononuclear cells (PBMCs) taken from 20 patients showed an enhanced proliferative response to colon carcinoma antigen and a significant reduction in suppressive regulatory T lymphocytes (CD4+CD25T-reg+). A cytofluorimetric study of the PBMCs of five HLA-A(*)02.01+ patients who achieved an objective response showed an increased frequency of cytolytic T lymphocyte precursors specific for known CEA- and TS-derived epitopes.

CONCLUSION

The results show that our regimen has strong immunologic and antitumor activity in colorectal cancer patients and deserves to be investigated in phase III trials.