Troschel Fabian M, Böhly Nicolas, Borrmann Katrin, Braun Timo, Schwickert Alexander, Kiesel Ludwig, Eich Hans Theodor, Götte Martin, Greve Burkhard
1 Department of Radiation Therapy-Radiation Oncology, University Hospital Münster, Münster, Germany.
2 Department of Gynecology and Obstetrics, University Hospital Münster, Münster, Germany.
Tumour Biol. 2018 Aug;40(8):1010428318791887. doi: 10.1177/1010428318791887.
Effectively targeting cancer stem cells, a subpopulation of tumorigenic, aggressive, and radioresistant cells, holds therapeutic promise. However, the effects of the microRNA miR-142-3p, a small endogenous regulator of gene expression on breast cancer stem cells, have not been investigated. This study identifies the influence of miR-142-3p on mammary stemness properties and breast cancer radioresistance to establish its role in this setting. miR-142-3p precursor transfection was performed in MDA-MB-468, HCC1806, and MCF-7 cells, and stem cell markers CD44, CD133, ALDH1 activity and mammosphere formation were measured. β-catenin, the canonical wnt signaling effector protein, was quantified by Western blots and cell fluorescence assays both in miR-142-3p-overexpressing and anti-miR-142-3p-treated cells. Radiation response was investigated by colony formation assays. Levels of BRCA1, BRCA2, and Bod1 in miR-142-3p-overexpressing cells as well as expression of miR-142-3p, Bod1, KLF4, and Oct4 in sorted CD44/CD24 cells were determined by quantitative polymerase chain reaction. miR-142-3p overexpression resulted in a strong decline in breast cancer stem cell characteristics with a decrease in CD44, CD133, ALDH1, Bod1, BRCA2, and mammosphere formation as well as reduced survival after irradiation. miR-142-3p expression was strongly reduced in sorted CD44/CD24 stem cells, while Bod1, Oct4, and KLF4 were overexpressed. β-catenin levels strongly decreased after miR-142-3p overexpression, but not after anti-miR-142-3p treatment. We conclude that miR-142-3p downregulates cancer stem cell characteristics and radioresistance in breast cancer, mediated by a reduced role of β-catenin in miR-142-3p-overexpressing cells. miR-142-3p might therefore help to target cancer stem cells.
有效靶向癌症干细胞（一群具有致瘤性、侵袭性和放射抗性的细胞亚群）具有治疗前景。然而，微小RNA miR - 142 - 3p（一种基因表达的内源性小调节因子）对乳腺癌干细胞的影响尚未得到研究。本研究确定了miR - 142 - 3p对乳腺干性特性和乳腺癌放射抗性的影响，以确立其在这种情况下的作用。在MDA - MB - 468、HCC1806和MCF - 7细胞中进行miR - 142 - 3p前体转染，并检测干细胞标志物CD44、CD133、ALDH1活性和乳腺球形成。通过蛋白质免疫印迹法和细胞荧光测定法对miR - 142 - 3p过表达细胞和抗miR - 142 - 3p处理细胞中的经典Wnt信号效应蛋白β - 连环蛋白进行定量。通过集落形成试验研究辐射反应。通过定量聚合酶链反应测定miR - 142 - 3p过表达细胞中BRCA1、BRCA2和Bod1的水平以及分选的CD44/CD24细胞中miR - 142 - 3p、Bod1、KLF4和Oct4的表达。miR - 142 - 3p过表达导致乳腺癌干细胞特征显著下降，CD44、CD133、ALDH1、Bod1、BRCA2减少以及乳腺球形成减少，同时辐射后存活率降低。在分选的CD44/CD24干细胞中miR - 142 - 3p表达强烈降低，而Bod1、Oct4和KLF4过表达。miR - 142 - 3p过表达后β - 连环蛋白水平显著降低，但抗miR - 142 - 3p处理后未降低。我们得出结论，miR - 142 - 3p下调乳腺癌中的癌症干细胞特征和放射抗性，这是由β - 连环蛋白在miR - 142 - 3p过表达细胞中的作用降低介导的。因此，miR - 142 - 3p可能有助于靶向癌症干细胞。
