Targeting miR-10b in Breast Cancer Bone Colonization Model Using Image-Guided Nucleic Acid-Based Therapeutics.

Background/Objectives: Breast cancer is the most frequently diagnosed cancer among women worldwide and a leading cause of cancer-related death. Despite the use of bisphosphonates, RANKL inhibitors, chemotherapy, and available endocrine therapies, the five-year survival rate for patients with bone metastases remains approximately 20-30%, underscoring the urgent need for novel, metastasis-specific therapeutic strategies. Recent studies demonstrated that miR-10b can serve as an attractive therapeutic target for the treatment of metastatic breast cancer, particularly in the context of bone metastasis. This study aimed to test antimir-10b therapeutics in a mouse model of breast cancer bone metastasis. Methods: We utilized a previously developed dextran-coated iron oxide nanoparticle-based platform for delivery of antisense anti-miR-10b oligonucleotides to bone metastases. The magnetic properties of the nanoparticles allowed for in vivo imaging of therapeutic delivery to metastatic tumors. Results: We showed the delivery of the therapeutics in the bone colonization model by in vivo imaging as well as significant survival benefits in injected animals. There was a significant inhibition of miR-10b following treatment that resulted in significant upregulation of the downstream target HOXD10 in vitro and a similar trend in vivo. Repeated dosing of the therapeutics was well tolerated, and no systemic toxicity was observed, supporting the safety profile of this approach. Conclusions: Collectively, these studies demonstrated that targeting miR-10b using an image-guided anti-miR-10b nanotherapeutic represents a promising and translatable strategy for targeting breast cancer bone metastases.