Smac mimetics as novel promising modulators of apoptosis in the treatment of breast cancer.

Breast cancer is the most prevalent cancer in women. Despite improvements in treatment, the rate of breast cancer-related deaths is still high, and this issue needs further, accurate investigations. Although several treatment options are available, none of them are efficient for complete remission, particularly in advanced stages of the disease. It is known that cancerous cells have dysregulated apoptosis-related pathways, by which they can remain alive for a long time, expand freely, and escape from apoptosis-inducing drugs or antitumor immune responses. Therefore, modulation of apoptosis resistance in cancer cells may be an efficient strategy to overcome current problems faced in the development of immunotherapeutic approaches for the treatment of breast cancer. The inhibitors of apoptosis protein (IAPs) are important targets for cancer therapy because it has been shown that these molecules are overexpressed and highly active in various cancer cells and suppress apoptosis process in malignant cells by blockage of caspase proteins. There is evidence of Smac mimetics efficacy as a single agent; however, recent studies have indicated the efficacy of current anticancer immunotherapeutic approaches when combined with Smac mimetics, which are potent inhibitors of IAPs and synthesized mimicking Smac/Diablo molecules. In this review, we are going to discuss the efficacy of treatment of breast cancer by Smac mimetics alone or in combination with other therapeutics.