MiR-1260a Promotes Proliferation and Migration in Breast Cancer

Background: MicroRNAs (miRNAs) regulate cellular and pathological processes, including cancer. As previously described by our group, miR-1260a was upregulated in breast cancer tissue. The aim of this research was to characterize miR-1260a in the breast cancer model. Methods: MiR-1260a levels were studied by RNA array and qRT-PCR in breast cancer patients. The role and mechanisms underlying miR-1260a-mediated breast cancer cell growth, invasion and target proteins were studied using proliferation assays, colony formation assays, western blot, RT-qPCR and immunohistochemistry. Results: Here, we found that miR-1260a expression is higher in luminal B tumors, followed by triple-negative tumors, and luminal A tumors in a clinical database of 50 breast cancer patients. Moreover, miR-1260a expression correlates positively with cyclin D1 protein. On the other hand, miR-1260a overexpression promotes the proliferation of MCF7, MDA-MD-231, MDA-MB-468, and T47D cells. In addition, miR-1260a induces the invasion of MCF7 and MDA-MB-231 cells. Moreover, our results suggest that the oncogenic properties of miR-1260a are linked to GCDH and ERP29 inhibition, two tumor suppressor proteins downregulated in breast cancer. Conclusion: These findings indicate that miR-1260a promotes the oncogenic properties of cancer cells and may be useful as a new potential therapeutic target in hormone-dependent (luminal A and B) and triple-negative breast cancer. Citation Format: Marina Bataller, Andrea Feliciano, Yilin Sun, Daniela Gala, Marc Biasini, Almudena Sánchez-García, Cristina Mir, Josep Castellvi, Sergi Benavente, Yoelsis García-Mayea, Matilde Esther LLeonart Pajarín. miR-1260a promotes proliferation and migration in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2049.