Purpose: Triple-negative breast cancer (TNBC) is an aggressive, lethal, and heterogeneous subtype of breast cancers, tending to have lower 5-year survival rates than other BC subtypes in response to conventional chemotherapies. This study's aim was to identify advanced regimens to effectively control TNBC tumor development.
Methods: We investigated the combination of the DNA synthesis inhibitor gemcitabine, the DNA-damaging agent cisplatin, and the histone deacetylase inhibitor romidepsin to control a variety of breast cells in vitro. We studied the toxicity of drug doses and administration schedules to determine tolerable combination regimens in immune-deficient nude and -competent BALB/c mice. We then studied the efficacy of tolerable regimens in controlling TNBC cell-derived xenograft development in nude mice. By reducing clinically equivalent doses of each agent in combination, we formulated tolerable regimens in animals. We verified that the tolerable triple combination gemcitabine plus romidepsin + cisplatin regimen more efficacious than double combination regimens in controlling xenograft tumor development in nude mice.
Results: A triple combination of gemcitabine + romidepsin + cisplatin synergistically induced death of the TNBC M.D. Anderson-Metastatic Breast cancer (MDA-MB) 231 and MDA-MB468, as well as Michigan Cancer Foundation (MCF) 7, MCF10A, and MCF10A-Ras cells. Cell death induced by gemcitabine + romidepsin + cisplatin was in a reactive oxygen species-dependent manner.
Conclusion: Considering the high costs for developing a new anticancer agent, we used the FDA-approved drugs gemcitabine, romidepsin (is approved for T-cell lymphoma and is under clinical trial for TNBC), and cisplatin to economically formulate an efficacious and safe combination regimen. The highly efficacious gemcitabine plus romidepsin + cisplatin regimen should be poised for efficient translation into clinical trials, ultimately contributing to reduced mortality and improved quality of life for TNBC patients.
Keywords: Cisplatin; Combination regimens; Gemcitabine; Romidepsin; Triple-negative breast cancer.