Abstract
Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype characterized by dysregulated PI3K/Akt signaling and hypoxia-induced angiogenesis, and it lacks estrogen, progesterone, and HER2 receptors. Plant-derived lupeol has been reported to modulate the PI3K/Akt and HIF-1α/VEGF pathways, although the influence of aquatic environmental conditions on their biological activity remains poorly understood. This study investigated how river water quality affects lupeol stability and its cytotoxic and signaling-modulating effects in TNBC cells. River samples representing pollution gradients were analyzed for electrical conductivity (145-820 µS/cm), total dissolved solids (95-540 mg/L), heavy metals (ΣCd, Pb, Hg, As: 0.02-0.38 mg/L), and polycyclic aromatic hydrocarbons (0.01-0.21 µg/L). Lupeol was conditioned in these waters before treatment of MDA-MB-231 and BT-549 cells. Lupeol incubated in relatively clean upstream water retained > 92% stability, reduced VEGF by 60-65%, inhibited Akt phosphorylation by approximately 58% (p < 0.001), decreased HIF-1α expression by 65-70%, increased apoptosis by 35-40%, and reduced cell viability by 50-60%. In contrast, conditioning in polluted downstream water reduced lupeol stability to approximately 70%, limited Akt inhibition to approximately 25%, decreased HIF-1α suppression to 30-40%, and reduced apoptosis to 15-20%. Pollution indicators correlated strongly with diminished pathway modulation (r = - 0.86 to - 0.88), while multivariate analysis explained 82% of the observed variation (R² = 0.82). These findings demonstrate that river water chemistry influences lupeol stability and its cytotoxic and pathway-modulating effects in TNBC cells under in vitro conditions. However, because the present study was limited to TNBC cell lines, the results do not establish cancer-selective activity or therapeutic efficacy. Future studies should incorporate appropriate normal or non-tumorigenic cell models to assess selectivity and in vivo models to evaluate pharmacological efficacy, systemic toxicity, and translational potential.