Cucurbitacin-B instigates intrinsic apoptosis and modulates Notch signaling in androgen-dependent prostate cancer LNCaP cells

Front Pharmacol. 2023 Jun 28:14:1206981. doi: 10.3389/fphar.2023.1206981. eCollection 2023.

Abstract

Introduction: Among numerous triterpenoids of the Cucurbitaceae family, Cucurbitacin-B (Cur-B) is being explored for its pharmacological attributes. Reports from previous studies have explicitly shown that Cur-B possesses substantial anticancer effects. The present report focuses on exploring the anticancer attributes of Cur-B against androgen-dependent PCa LNCaP cells. Methods: LNCaP cells were exposed to commercially available purified Cur-B at varying concentrations that were selected as 5, 10, 15, 20, and 25 µM for some time of 24 h to perform various experimental studies. Results: Cytotoxicity evaluation revealed that Cur-B impeded the LNCaP cell's viability at 5 µM (p <0.05) which increased considerably at a concentration of 25 µM (p <0.001). Cur-B was also efficacious in inducing the changes within nu-clear morphology followed by a concomitant increase in the activities of key caspases including caspase-3, -8, and -9 intriguingly in a dose-dependent trend. Cur-B treatment not only resulted in the augmentation of intracellular ROS levels within LNCaP cells at 5 µM (p <0.05) but also in-creased significantly at 25 µM concentration (p <0.001). Elevation in the ROS levels was also found to be correlated with dissipated mitochondrial membrane potential (ΔΨm) which culminated in the onset of significant apoptosis at 25 µM concentration (p <0.001). Cur-B exposure also resulted in the downregulation of cyclin D1, cyclin-dependent kinase 4 (CDK4) followed by amplified levels of p21Cip1 mRNA. Importantly, exposure of Cur-B competently reduced the expression of the Notch signaling cascade which may be the plausible cause behind Cur-B-instigated apoptotic cell death and cell cycle arrest in LNCaP cells. Discussion: These observations thus, explicitly indicated that Cur-B could be plausibly further explored as potent therapeutics against androgen-dependent PCa.

Keywords: Notch signaling; anti-cancer; apoptosis; cell cycle; cucurbitacin-B.

Grants and funding

This research has been funded by Deputy for Research and Innovation, Ministry of Education through Initiative of Institutional Funding at University of Ha’il—Saudi Arabia through project number IFP-22 112.