Chemotherapeutic Vulnerability of Triple-negative Breast Cancer Cell-derived Tumors to Pretreatment with Vernonia amygdalina Aqueous Extracts

Background: Unresponsive to most clinical therapies, triple-negative breast cancer (TNBC) is the dominant biological cause of population-based racioethnic disparities in breast cancer mortality in the United States. We report the chemotherapeutic vulnerability of TNBC cells and stem cell-derived tumors to Vernonia amygdalina aqueous leaf extracts (VA extracts). VA extracts arrest cell proliferation and induce apoptosis in vitro and inhibit growth of implanted tumors and show chemo-preventive efficacy in vivo. Materials and Methods: HRAS cells and MDA-MB-468 cells were subcutaneously implanted into nude mice with or without pretreatment with VA extracts before chemotherapeutic treatment with VA extracts and/or paclitaxel to evaluate their ability to inhibit tumor growth. Results: The most significant reduction in tumor volume was observed in the MDA-MB-468 cell-induced tumors following VA extract pre-treatment compared to those from HRAS cell implantation. Conclusion: VA extracts induce apoptosis, exhibit additive effects, inhibit tumor growth and display chemo-preventive actions against TNBCs.