biostudies-literatureUnknown15(1)Opperman RMNatural Sciences and Engineering Research Council of CanadaCanada Graduate Scholarships – Master’s programResearch Manitoba’s CFI Matching FundLotte and John Hecht Memorial FoundationBreast Cancer CanadaResearch Manitoba masters studentshipCanada Foundation for InnovationCanada Research ChairsDoxorubicin is an effective treatment for breast cancer, but drug resistance poses a significant challenge. Emerging regulators of drug resistance include microRNAs, small non-coding RNAs. Two miRNAs, miR-526b and miR-655, promote aggressive breast cancer phenotypes like cell proliferation, cancer stem cell upregulation, altered response to oxidative and metabolic stress and help tumor metastasis by activating COX-2/EP4/PI3K pathways. However, their impact on the effects of chemotherapeutic treatments remains unexplored. This study investigates the impact of overexpressing miR-526b and miR-655 on doxorubicin responses in breast cancer, focusing on pro-survival, apoptotic, and DNA-damage response pathways. We confirm the role of PI3K/Akt signalling in promoting cell survival and resistance Scientific reports33584https://www.ebi.ac.uk/biostudies/studies/S-EPMC12480915biostudies-literatureInvestigating the effects of miR-526b and miR-655 on doxorubicin sensitivity in breast cancer.PMC12480915Opperman RMMajumder MMaiti SfalseInvestigating the effects of miR-526b and miR-655 on doxorubicin sensitivity in breast cancer.Doxorubicin is an effective treatment for breast cancer, but drug resistance poses a significant challenge. Emerging regulators of drug resistance include microRNAs, small non-coding RNAs. Two miRNAs, miR-526b and miR-655, promote aggressive breast cancer phenotypes like cell proliferation, cancer stem cell upregulation, altered response to oxidative and metabolic stress and help tumor metastasis by activating COX-2/EP4/PI3K pathways. However, their impact on the effects of chemotherapeutic treatments remains unexplored. This study investigates the impact of overexpressing miR-526b and miR-655 on doxorubicin responses in breast cancer, focusing on pro-survival, apoptotic, and DNA-damage response pathways. We confirm the role of PI3K/Akt signalling in promoting cell survival and resistance 2025-01-01T00:00:00Z2025 Sep2026-07-15T09:49:49.782Z2026-07-02T03:12:12.786ZS-EPMC124809154102316710.1038/s41598-025-18719-y