3-Acetyl-11-keto-β-boswellic acid (AKBA) induced antiproliferative effect by suppressing Notch signaling pathway and synergistic interaction with cisplatin against prostate cancer cells

Studies on the assessment of anticancer efficacy of plant-derived phytochemicals by targeting signaling pathways have drawn a lot of attention recently for human health. Multiple investigations have proposed an involvement of Notch pathway in the processes of cancer angiogenesis and metastasis, and drug resistance. Moreover, overexpression of Notch signaling is associated with increased prostate cancer (PrCa) cell growth and development. A number of chemotherapeutic agents are reported to become resistant over a period of time and have severe side effects. To increase efficacy and lessen drug-induced toxicity, a variety of bioactive compounds have been utilized alone or as adjuncts to traditional chemotherapy. Therefore, in the present study, the potential of AKBA in inhibiting the proliferation of PrCa cells by modulating Notch signaling components and its efficacy in combination with cisplatin was investigated. The results exhibited a substantial reduction in cell survival (IC50 = 25.28 µM at 24 h and 16.50 µM at 48 h) and cellular alterations in AKBA-treated PrCa cells. Additionally, AKBA caused nuclear condensation, increased reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, and caspase activation, ultimately leading to apoptosis in PrCa cells. Moreover, AKBA-elicited apoptosis was evidenced by an augmentation in the Bax to Bcl2 ratio. AKBA was also found to induce G0/G1 arrest which was substantiated by reduced cyclin D1 and CDK4 expression levels concomitantly with increased expression of p21 and p27 genes. Intriguingly, AKBA demonstrated significant downregulation of Notch signaling mediators. Furthermore, the isobolograms of the combination treatment indicated that AKBA has the potential to synergistically enhance the cytotoxic efficacy of cisplatin in DU145 cells, as evidenced by CI