Investigation of anti-cancer efficiency of DZNep and stauprimide combination in breast cancer

Abstract

Objective: Breast cancer represents a significant clinical challenge due to tumor heterogeneity and the presence of therapy-resistant cancer stem cells (CSCs). The combination of epigenetic modulators and differentiation-inducing agents has emerged as a promising therapeutic strategy. In this study, we aimed to evaluate the anticancer effects of combining the methyltransferase inhibitor 3-Deazaneplanocin A (DZNep) and the MYC transcription inhibitor Stauprimide on breast cancer cell lines and breast cancer stem cells (BCSCs). Methods: Cytotoxicity was determined by real-time cell analysis (RTCA) to calculate IC₅₀ values and evaluate the synergistic potential of the combination using isobologram analyses. Apoptosis induction and cell cycle distribution were assessed via flow cytometry using Annexin V-FITC/PI staining and DNA content analysis, respectively. Cell migration was evaluated using wound-healing assays. Additionally, quantitative RT-PCR was performed to analyze expression changes in key apoptosis – and cell cycle-related genes following treatment. Results: The combination of DZNep and Stauprimide (1:1 ratio) demonstrated significant synergistic cytotoxicity in MCF-7 (luminal A) and MDA-MB-231 (triple-negative) breast cancer cells, substantially reducing effective doses of both agents (combination index values of 0.671 and 0.134, respectively). Treatment markedly induced apoptosis, triggered cell cycle arrest predominantly at G2/M and G0/G1 phases, increased polyploidy, and significantly inhibited migration. Notably, the combination selectively induced apoptosis and modulated gene expression (e.g., TP53 and p27 upregulation) in BCSCs, while exhibiting minimal toxicity towards the normal mammary epithelial cell line, MCF-10A. The combination of DZNep and Stauprimide exerts potent anticancer effects by selectively inducing apoptosis, cell cycle arrest, and suppressing migration in breast cancer cells, including CSC populations. Conclusion: These findings suggest translational potential for preventing recurrence and metastasis, positioning this therapeutic strategy as a promising candidate for further validation in preclinical and clinical studies.