Synergistic Inhibition of Angiogenesis and Tumor Progression by CD73 Inhibitor and Menstrual Blood Stem Cell-Derived Exosomes via miR-422a Upregulation in HER2-Positive Breast Cancer

Objective: HER2-positive breast cancer (HER2+ BC) remains an aggressive subtype with limited treatment efficacy due to therapeutic resistance and systemic toxicities. CD73, an ectoenzyme producing extracellular adenosine, promotes tumor progression by enhancing angiogenesis, immune evasion, and metastasis. Exosomes derived from menstrual blood mesenchymal stem cells (Exo-Mens) exhibit anti-tumor and anti-angiogenic effects through bioactive cargo delivery. This study investigated the synergistic therapeutic potential of CD73 inhibition (using APCP) combined with Exo-Mens in HER2+ BC, with particular focus on their effects on angiogenesis-related pathways and on the regulation of miR-20a and miR-422a. Materials and Methods: values and synergy indices. Functional assays (colony formation, scratch migration assay), flow cytometry for apoptosis, and qRT-PCR analysis of pro-angiogenic (HIF-1α, KDR), pro-invasive (NF-κB, MMP9), and microRNAs (miR-20a, miR-422a) were performed. Results: = 61.84 µg/mL). Combination therapy demonstrated strong synergy (combination index < 1), significantly reducing colony formation (10.41% vs. 100% in controls), and cell migration (26.13% wound closure vs. 100% control). Both treatments downregulated angiogenesis factors (HIF-1α, KDR), while invasion markers (NF-κB, MMP9) showed treatment-specific responses. Notably, miR-422a was significantly upregulated across treatments, with the highest fold-change in the combination (3.05 ± 0.05), whereas miR-20a showed only modest changes. Combination therapy also enhanced apoptosis (viable cells reduced to 46.2% vs. 89.1% control). Conclusion: The combination of APCP and Exo-Mens demonstrated synergistic anti-tumor effects in HER2+ BC cells by targeting pathways related to angiogenesis, proliferation, and apoptosis. In this context, the upregulation of miR-422a suggests a potential tumor-suppressive role, warranting further investigation.