Synergistic Induction of Apoptosis and Cell Cycle Arrest against Breast Cancer Cells by Combined Kaempferol and Paclitaxel

Abstract The study investigates the potential of combining Kaempferol (KAE) and Paclitaxel (PAC) to enhance anti-cancer effects and induce apoptosis in MDA-MB-468 triple-negative breast cancer cells and human normal foreskin fibroblast cells. For this porpose, the cells were treated with PAC, KAE, and their combination for 24, 48, and 72 hours. Cytotoxicity was assessed via MTT assay, and synergy was evaluated using Combination Index analysis. Apoptosis was quantified via Annexin V/PI staining and DAPI staining. Flow cytometry analyzed cell cycle arrest, while qPCR assessed apoptotic gene expression. The combination of KAE and PAC exhibited a synergistic anti-proliferative effect, significantly reducing MDA-MB-468 cell viability compared to monotherapies. Annexin V/PI staining revealed an increased apoptotic rate (73%) in co-treated cells, with enhanced chromatin condensation and nuclear fragmentation observed via DAPI staining. Flow cytometry indicated a marked increase in SubG1 phase cells, confirming apoptosis induction. Gene expression analysis demonstrated upregulation of pro-apoptotic BAD and downregulation of anti-apoptotic Bcl-2 and Mcl-1, highlighting the activation of apoptosis pathways. The combination of PAC and KAE enhances cytotoxicity, promotes apoptosis, and alters key apoptotic gene expressions in MDA-MB-468 cells while sparing normal fibroblast cells. These findings suggest a promising therapeutic strategy for triple-negative breast cancer.