Functional Analysis of Extracellular Vesicle-Associated miRNAs from Mammary Tumor, Adipose Tissue and Serum in Mice with Diet-Induced Obesity

<span data-contrast="none">Women with obesity are proven to be at a higher risk of triple negative breast cancer (TNBC) development. Understanding obesity's effect on the expression of TNBC-associated genes could allow for the development of clinical interventions against tumor progression and metastatic growth. </span><span data-contrast="auto">MicroRNAs (miRNAs) play a key role in the transcriptional regulation of gene expression. They can be transported out of cells via small, membrane-enclosed nanoparticles called extracellular vesicles (EVs). This research aims to evaluate the EV-derived miRNAs extracted from the mammary tumor, visceral adipose tissue (VAT), and serum of diet-induced obese (DIO) and control mice. </span><em>We hypothesize that differentially expressed miRNAs in EVs isolated from the tissues of mice with obesity will increase cancer cell viability and proliferation through upregulation of genes related to growth and differentiation.&nbsp;</em> <span data-contrast="auto">Female C57BL/6 mice were randomized to receive either a control or DIO diet. At the onset of obesity in the DIO group, mammary tumor growth was induced in both groups by orthotopically injecting metMWnt</span><span data-contrast="auto">lung</span><span data-contrast="auto"> cells (a murine model of metastatic TNBC).</span> <span data-contrast="auto">These EVs were purified and the miRNA content was analyzed by small RNA sequencing.</span> <span data-contrast="auto">Differential miRNA expression was analyzed using DESeq2, followed by in silico target gene identification via miRTargetLink 2.0, miRTarBase, and miRDB. Pathway analysis was conducted using DAVID. To validate functional relevance, </span><span data-contrast="auto">metMWnt</span><span data-contrast="auto">lung</span><span data-contrast="auto"> cells were reverse transfected with mimics and inhibitors of select miRNAs, followed by RNA isolation, qPCR, and MTT assays to assess gene expression and cell viability.</span> DAVID analysis revealed enrichment in carcinogenesis-related pathways<span data-contrast="none">. </span><span data-contrast="auto">In vitro assays confirmed that modulating miRNA expression affected cancer cell viability and associated target gene expression. These findings suggest that obesity-associated EV-derived miRNAs may contribute to TNBC progression and offer potential targets for therapeutic intervention.</span><span data-contrast="none">&nbsp;</span><span data-ccp-props="{&quot;134233117&quot;:false,&quot;134233118&quot;:false,&quot;201341983&quot;:0,&quot;335559738&quot;:240,&quot;335559739&quot;:240,&quot;335559740&quot;:279}">&nbsp;</span>