Immunotherapeutic Approach to Breast Cancer: The Anti-Tumor Effect of Anti-IL-6 Monoclonal Antibodies in Malignant Mammary Tumor Implanted-Mice.

It has been established that suppression of apoptosis during carcinogenesis is the main cause of development and progression of breast cancer. Breast cancer patients have higher circulating levels of IL-6 protecting cancer cells from apoptosis and positively correlated with poor prognosis of the disease. The current work is carried out to fulfill one of our in vivo preclinical studies' for approaching a novel breast cancer immunotherapy through induction of tumor cell apoptosis. The study aims at investigating the potential of anti-IL-6 monoclonal antibodies (mAbs) to suppress IL-6 anti-apoptotic activities in tumor microenvironment of malignant mammary tumor implanted-mice. To achieve this goal, 4 groups of mice were used, group I: served as control, group II: mice implanted with Ehrlich ascites carcinoma cell lines (EAC), through intramuscular injection till tumor inoculation, group III: injected intratumorally with10 µl saline for 3 successive days, and group IV: mice were injected intratumorally one day after tumor inoculation with a dose of 1.5 mg / kg of recombinent anti-IL-6 monoclonal antibodies in10 µl saline for 3 successive days. Apoptosis was evaluated in tumor samples from anti-IL-6 treated tumor implanted mice and compared with controls. Levels of apoptosis in tumor tissue samples of tumor implanted mice treated with anti-IL-6 were significantly (P=0.009) higher than untreated ones. In conclusion, anti-IL-6 monoclonal antibodies have the potential to suppress the anti-apoptotic effect of interleukin-6 (IL-6) within the tumor microenvironment of tumor implanted in mice.