Piper nigrum L. Extract Modulates Cell Cycle and Promotes Apoptosis-Like Cell Death in BT-474 Breast Cancer Cells...

Cancer therapy remains challenging because of recurrence, drug resistance, and severe side effects, driving the search for novel complementary strategies. In this study, we explore, for the first time, the potential of Piper nigrum L. (P. nigrum L. black pepper), a widely used spice known for its bioactive properties, in treating BT-474 luminal B and MCF-7 luminal A breast cancer cells.

BT-474 cells were treated with P. nigrum L. ethanolic extract (PNEE). Cytotoxicity, cell morphology, gene and protein expression, cell death and cell cycle progression were evaluated using the MTT, microscopy, Reverse Transcriptase Quantitative Polymerase Chain Reaction (RT-qPCR), Enzyme-Linked Immunosorbent Assay (ELISA), and flow cytometry, respectively. MCF-7 cells were included as a comparative breast cancer model, whereas 3T3-L1 cells were used as a non-cancerous model.

Our findings demonstrate PNEE's multimodal activity in BT-474 cells, decreasing cell viability with an IC₅₀ of 58 ppm, and significantly suppressed colony formation. PNEE induced S-phase cell cycle arrest, and modulated several cancer-associated markers, including EGFR, PI3K/AKT pathway components, cyclin A, MMP-9, HIF-1α, and BCL2. Furthermore, PNEE elicited a regulated cell death phenotype with apoptotic features, distinct Annexin V/PI profiles in BT-474 luminal B and MCF-7 luminal A breast cancer cells. In addition, PNEE showed lower cytotoxicity toward non-cancerous 3T3-L1 cells under experimental condition tested.

PNEE exerts multiple anticancer effects in BT-474 luminal B breast cancer cells and induces a regulated cell death phenotype that does not fully conform to a canonical caspase-dependent apoptotic pattern. Distinct cell death responses observed between BT-474 and MCF-7 cells further suggest that breast cancer subtype-specific factors may influence the cellular response to PNEE. These findings support further investigation of PNEE, including mechanistic studies and evaluation of efficacy and safety in appropriate in vivo models.