Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy.
Am J Pathol. 2013 Jun;182(6):2058-70. doi: 10.1016/j.ajpath.2013.02.046. Epub 2013 Apr 23.
In an attempt to reveal deregulated miRNAs associated with the progression of carcinomas developed in BALB-neuT transgenic mice, we found increased expression of miR-135b during malignancy. Relevantly, we observed that miR-135b is up-regulated in basal or normal-like human breast cancers, and it correlates with patient survival and early metastatization. Therefore, we investigated its biological functions by modulating its expression (up- or down-regulation) in mammary tumor cells. Although no effect was observed on proliferation in cell culture and in orthotopically injected mice, miR-135b was able to control cancer cell stemness in a mammosphere assay, anchorage-independent growth in vitro, and lung cancer cell dissemination in mice after tail vein injections. Focusing on the miR-135b molecular mechanism, we observed that miR-135b controls malignancy via its direct targets, midline 1 (MID1) and mitochondrial carrier homolog 2 (MTCH2), as proved by biochemical and functional rescuing/phenocopying experiments. Consistently, an anti-correlation between miR-135b and MID1 or MTCH2 was found in human primary tumor samples. In conclusion, our research led us to the identification of miR-135b and its targets, MID1 and MTCH2, as relevant coordinators of mammary gland tumor progression.
为了揭示与 BALB-neuT 转基因小鼠中发生的癌进展相关的失调 miRNA，我们发现 miR-135b 在恶性肿瘤中表达增加。相关地，我们观察到 miR-135b 在基底或正常样人乳腺癌中上调，并且与患者生存和早期转移相关。因此，我们通过在乳腺肿瘤细胞中调节其表达（上调或下调）来研究其生物学功能。尽管在细胞培养和原位注射的小鼠中观察到对增殖没有影响，但 miR-135b 能够在乳腺球体测定、体外无锚定生长以及尾静脉注射后小鼠肺癌细胞扩散中控制癌症干细胞特性。关注 miR-135b 的分子机制，我们观察到 miR-135b 通过其直接靶标中线 1（MID1）和线粒体载体同源物 2（MTCH2）来控制恶性肿瘤，这通过生化和功能挽救/表型复制实验得到证实。一致地，在人原发性肿瘤样本中发现了 miR-135b 与其靶标 MID1 或 MTCH2 之间的负相关关系。总之，我们的研究导致鉴定出 miR-135b 及其靶标 MID1 和 MTCH2 作为乳腺肿瘤进展的相关协调因子。
