Combination of endostatin and vinorelbine enhances control of breast cancer cells while endostatin ameliorates the toxicity of vinorelbine in normal cells
Surgery, chemotherapy and radiotherapy, which are known as conventional cancer treatments, have been applied for more than 40 years. Because the target of chemotherapy is tumor cells, treatment agents are used at high doses during application and this creates toxic responses, causing side effects in normal cells. Furthermore, due to the high doses, cancer cells develop resistance to the agent and, as a result, success of the treatment gradually decreases. That is why chemotherapy is combined with various other cancer treatments to increase the therapeutic efficacy while reducing the side effects. In this study, the cytotoxic effect of endostatin, vinorelbine and their combination on breast cancer cell line MDAMB 231 was researched in vitro. In addition, the effects caused by the combination on TRAIL, TNF-α and caspase-2, 3, 6, 8 and -9 proteins, which undertake key roles in apoptosis were investigated. Cytotoxic effects of both agents and their combinations on normal epithelial cells (293 T) were also studied and compared. We found that endostatin is cytotoxic for cancer cells through caspase-8 and TNF-α activation, which affects the extrinsic pathway of apoptosis Combining endostatin as an anti-angiogenic agent with vinorelbine significantly suppressed the cytotoxicity that vinorelbine exerts on normal cells.