Chitosan nanoparticles loaded with metformin and digoxin synergistically inhibit MCF-7 breast cancer cells through suppression of NOTCH-1 and HIF-1α gene expression.

This study investigated the potential anticancer efficacy of co-treating the MCF-7 breast cancer cell line with chitosan nanoparticles (Cs NPs) loaded with metformin (Met) and digoxin (Dig). The Cs NPs had a size range of 90.6-148.7 nm and a zeta potential of +11.7 to +11.9 mV, indicating a positive surface charge. Notably, the Cs NPs demonstrated high encapsulation efficiencies, with values of 90.97 ± 5.14 % for Met and 92.12 ± 3.81 % for Dig, indicating effective loading of both drugs. The results revealed that the co-delivery of Met and Dig via Cs NPs significantly enhanced the anticancer efficacy, outperforming the treatment with individual free drugs or their combination, thereby demonstrating the potential benefits of nanoparticle-mediated co-administration. The drugs-loaded Cs NPs induced a marked increase in apoptosis in MCF-7 cells, with a cell death rate of 67.56 %, and significantly reduced mammosphere size by 48.08 %, thereby demonstrating a superior therapeutic efficacy compared to treatment with individual free drugs or their combination. Notably, the drug-loaded Cs NPs exhibited potent anti-migratory and anti-angiogenic effects, significantly inhibiting cell migration and new blood vessel formation, which may contribute to overcoming the inherent resistance of tumors to conventional therapies. Mechanistically, the co-treatment with drugs-loaded Cs NPs was found to downregulate the expression of NOTCH-1 and HIF-1α, two key transcription factors involved in tumor cell survival and adaptation, suggesting that their inhibition is a crucial component of the therapeutic efficacy of this treatment strategy. Collectively, the findings of this study suggest that the co-delivery of Met and Dig via chitosan Cs NPs represents a promising therapeutic strategy for breast cancer, as it effectively targets key pathways involved in tumor growth and progression, and underscores the potential of Cs NPs as a versatile platform for cancer therapy.