BCL-2 Inhibitor Venetoclax Induces Autophagy-Associated Cell Death, Cell Cycle Arrest, and Apoptosis in Human Breast Cancer Cells

Ali Alhoshani; Fahad O Alatawi; Fawaz E Al-Anazi; Ibraheem M Attafi; Asad Zeidan; Abdelali Agouni; Heba M El Gamal; Licia S Shamoon; Sarah Khalaf; Hesham M Korashy

doi:10.2147/OTT.S281519

BCL-2 Inhibitor Venetoclax Induces Autophagy-Associated Cell Death, Cell Cycle Arrest, and Apoptosis in Human Breast Cancer Cells

Onco Targets Ther. 2020 Dec 31:13:13357-13370. doi: 10.2147/OTT.S281519. eCollection 2020.

Authors

Affiliations

¹ Department of Pharmacology & Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.
² Poison Control & Medical Forensic Chemistry Center, Jazan Health Affairs, Jazan, Saudi Arabia.
³ Department of Biomedical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar.
⁴ Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha, Qatar.

Abstract

Introduction: Venetoclax (VCX) is a selective BCL-2 inhibitor approved for the treatment of leukemia and lymphoma. However, the mechanisms of anti-cancer effect of VCX either as a monotherapy or in combination with other chemotherapeutic agents against breast cancer need investigation.

Methods: Breast cancer cell lines with different molecular subtypes (MDA-MB-231, MCF-7, and SKBR-3) were treated with different concentrations of VCX for indicated time points. The expression of cell proliferative, apoptotic, and autophagy genes was determined by qRT-PCR and Western blot analyses. In addition, the percentage of MDA-MB-231 cells underwent apoptosis, expressed higher oxidative stress levels, and the changes in the cell cycle phases were determined by flow cytometry.

Results: Treatment of human breast cancer cells with increasing concentrations of VCX caused a significant decrease in cells growth and proliferation. This effect was associated with a significant increase in the percentage of apoptotic MDA-MB-231 cells and in the expression of the apoptotic genes, caspase 3, caspase 7, and BAX, with inhibition of anti-apoptotic gene, BCL-2 levels. Induction of apoptosis by VCX treatment induced cell cycle arrest at G0/G1 phase with inhibition of cell proliferator genes, cyclin D1 and E2F1. Furthermore, VCX treatment increased the formation of reactive oxygen species and the expression level of autophagy markers, Beclin 1 and LC3-II. Importantly, these cellular changes by VCX increased the chemo-sensitivity of MDA-MB-231 cells to doxorubicin.

Discussion: The present study explores the molecular mechanisms of VCX-mediated inhibitory effects on the growth and proliferation of TNBC MDA-MB-231 cells through the induction of apoptosis, cell cycle arrest, and autophagy. The study also explores the role of BCL-2 as a novel targeted therapy for breast cancer.

Keywords: BCL-2; MDA-MB-231 cells; apoptosis; autophagy; breast cancer; cell cycle; venetoclax.

Grants and funding

The authors are very grateful to the Office of Research Support at Qatar University (grants # IRCC-2019-006, QUCG-CPH-20/21-1, QUST-2-CPH-2020-3) and the Qatar Foundation – Qatar National Research Fund (grant # UREP24-163-3-049) for funding this study. Open access funding was provided by the Qatar National Library.