Aging is one of the inherent risk factors for breast cancer. Although the influence of age-related cellular alterations on breast cancer development has been extensively explored, little is known about the alterations in the aging breast tissue microenvironment, specifically the extracellular matrix (ECM). Here, for the first time in literature, we have identified tissue resident matrix bound vesicles (MBVs) within the healthy mouse breast ECM, investigated and compared their characteristics in young and aged healthy breast tissues, and studied the effects of these MBVs on normal (KTB21) and cancerous (MDA-MB-231) human mammary epithelial cells with respect to the tissue age that they are extracted from. Using vesicle labeling technology, we were able to visualize cellular uptake of the MBVs directly from the native decellularized tissue sections, showing that these MBVs have regulatory roles in the tissue microenvironment. We mimicked the ECM by embedding the MBVs in collagen gels, and showed that MBVs could be taken up by the cells. The miRNA and cytokine profiling showed that MBVs shifted towards a more tumorigenic and invasive phenotype with age, as evidenced by the more pronounced presence of cancer-associated cytokines, and higher expression levels of oncomiRs miR-10b, miR-30e, and miR-210 in MBVs isolated from aged mice. When treated with MBVs or these upregulated factors, KTB21 and MDA-MB-231 cells showed significantly higher motility and invasion compared to untreated controls. Treatment of cells with a cocktail of miRNAs (miR-10b, miR-30e, and miR-210) or with the agonist of adiponectin (AdipoRon), which both were enriched in the aged MBVs, recapitulated the effect of aged MBVs on cells. This study shows for the first time that the MBVs have a regulatory role in the tissue microenvironment and that the MBV contents change towards cancer-promoting upon aging. Studying the effects of MBVs and their cargos on cellular behavior could lead to a better understanding of the critical roles of MBVs played in breast cancer progression and metastasis.

中文翻译：

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老化乳腺基质结合囊泡促进乳腺癌侵袭

衰老是乳腺癌的固有危险因素之一。尽管与年龄相关的细胞变化对乳腺癌发展的影响已被广泛探索，但人们对衰老乳腺组织微环境，特别是细胞外基质（ECM）的变化知之甚少。在这里，我们首次在文献中鉴定了健康小鼠乳腺 ECM 内的组织驻留基质结合囊泡 (MBV)，研究并比较了它们在年轻和老年健康乳腺组织中的特征，并研究了这些 MBV 对正常乳腺的影响。 KTB21）和癌性（MDA-MB-231）人乳腺上皮细胞相对于它们提取的组织年龄。使用囊泡标记技术，我们能够直接从天然脱细胞组织切片中观察细胞对 MBV 的摄取，表明这些 MBV 在组织微环境中具有调节作用。我们通过将 MBV 嵌入胶原凝胶中来模拟 ECM，并表明 MBV 可以被细胞吸收。miRNA 和细胞因子分析显示，随着年龄的增长，MBV 转向更具致瘤性和侵袭性的表型，癌症相关细胞因子的存在更加明显，以及 oncomiRs miR-10b、miR-30e 和 miR-210 的表达水平更高就证明了这一点。在从老年小鼠中分离出的 MBV 中。当用 MBV 或这些上调因子处理时，与未处理的对照相比，KTB21 和 MDA-MB-231 细胞表现出显着更高的运动性和侵袭性。用 miRNA 混合物（miR-10b、miR-30e 和 miR-210）或脂联素激动剂 (AdipoRon) 处理细胞（两者均富含老化 MBV），重现了老化 MBV 对细胞的影响。这项研究首次表明，MBV 在组织微环境中具有调节作用，并且随着年龄的增长，MBV 含量会向促癌方向变化。研究 MBV 及其货物对细胞行为的影响可以更好地了解 MBV 在乳腺癌进展和转移中发挥的关键作用。