Selective Anticancer Effects of Portulaca grandiflora via Apoptosis and NF-κB Pathway Modulation in MDA-MB-231 Cells

Breast cancer remains the most prevalent malignancy worldwide, with triple-negative breast cancer (TNBC) being particularly aggressive and resistant to standard therapies. Plant-derived compounds have emerged as promising alternatives due to selective cytotoxicity and reduced adverse effects. Portulaca grandiflora (Portulacaceae), ornamental succulent rich in flavonoids, phenolics, carotenoids, and sterols-phytochemicals commonly associated with anticancer activity-was evaluated for its pro-apoptotic and anti-metastatic potential. Three crude extracts, methanolic (PGM), ethanolic (PGE), and n-hexane (PGH), were initially screened for cytotoxicity, after which the two most active extracts, PGM and PGH, were selected for detailed mechanistic analysis. MTT assay was used for antiproliferative screening against MDA-MB-231 TNBC cells and non-tumorigenic MCF-10 A breast epithelial cells. Apoptosis induction was assessed using sub-G1 cell cycle arrest, Annexin V/PI staining, DNA fragmentation, and caspase-3/7 activation assays. NF-κB signaling and associated survival proteins were evaluated through Western blot, luciferase reporter, and DNA-binding assays. Anti-migratory and anti-invasive effects were analyzed using wound healing and transwell invasion assays. PGM showed the lowest IC₅₀ (79.5 µg/mL at 72 h) with minimal toxicity to MCF-10 A cells. Both PGM and PGH triggered sub-G1 accumulation and dose-dependent apoptosis, with PGM eliciting stronger caspase-3/7 activation, DNA fragmentation, and PARP cleavage. Notably, PGM inhibited NF-κB DNA-binding activity by ~ 60% compared to ~ 40% with PGH, reduced IκBα, TAK1, and Akt phosphorylation, and prevented nuclear p65 translocation, accompanied by downregulation of Bcl-2, Bcl-xL, XIAP, survivin, and Cyclin D1. Migration and invasion were significantly suppressed (p < 0.01), confirming anti-metastatic efficacy. Collectively, these findings demonstrate that P. grandiflora extracts-especially PGM-selectively induce apoptosis and impede metastasis in TNBC cells through suppression of NF-κB signaling activity (association-based evidence), supporting its potential as a phytochemical source for targeted breast cancer therapy. Because pathway-causality was not tested using NF-κB rescue or pharmacological inhibition controls, the mechanistic conclusions are presented as supportive associations rather than definitive proof. Future studies should focus on bioassay-guided compound purification, synergistic combination assessment, and in vivo validation for translational advancement.