Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P,R, China.
Cancer Cell Int. 2013 Oct 10;13(1):95. doi: 10.1186/1475-2867-13-95.
MicroRNAs are a class of endogenous single strand non-coding RNAs that are involved in many important physiological and pathological processes. The purpose of this study was to examine the expression levels of miR-497 in human breast cancer and its function in MDA-MB-231 breast cancer cells.
Quantitative polymerase chain reaction was used to measure the expression levels of miR-497 in 40 breast cancer specimens and adjacent normal breast tissues. MTT assays, colony formation assays, wound healing assays, transwell assays and cell cycle assays were used to explore the potential function of miR-497 in MDA-MB-231 breast cancer cells. Dual-luciferase reporter assays were performed to analyze the regulation of putative target of miR-497, and western blot assays were used to validate the dual-luciferase results.
The expression of miR-497 in breast cancer specimens was lower than adjacent normal tissues (P < 0.05). Overexpression of miR-497 inhibited cellular growth, suppressed cellular migration and invasion, and caused a G1 arrest. Dual-luciferase reporter assays showed that miR-497 binds the 3'-untranslated region (3'-UTR) of cyclin E1, suggesting that cyclin E1 is a direct target of miR-497. Western blot assays confirmed that overexpression of miR-497 reduced cyclin E1 protein levels.
MiR-497 may act as a tumor suppressor gene in breast cancer. Inhibited cellular growth, suppressed cellular migration and invasion, and G1 cell cycle arrest were observed upon overexpression of miR-497 in cells, possibly by targeting cyclin E1. These results indicate miR-497 could be considered a therapeutic target for the development of treatment for breast cancer.
microRNAs 是一类内源性单链非编码 RNA，参与许多重要的生理和病理过程。本研究旨在检测 miR-497 在人乳腺癌中的表达水平及其在 MDA-MB-231 乳腺癌细胞中的功能。
采用实时定量聚合酶链反应检测 40 例乳腺癌标本及其相邻正常乳腺组织中 miR-497 的表达水平。MTT 试验、集落形成试验、划痕愈合试验、Transwell 试验和细胞周期试验用于探讨 miR-497 对 MDA-MB-231 乳腺癌细胞潜在功能的影响。双荧光素酶报告基因实验分析 miR-497 的潜在靶基因，Western blot 实验验证双荧光素酶实验结果。
乳腺癌标本中 miR-497 的表达低于相邻正常组织（P<0.05）。miR-497 过表达抑制细胞生长，抑制细胞迁移和侵袭，并导致 G1 期阻滞。双荧光素酶报告基因实验显示，miR-497 结合 cyclin E1 的 3'-非翻译区（3'-UTR），提示 cyclin E1 是 miR-497 的直接靶基因。Western blot 实验证实 miR-497 过表达降低 cyclin E1 蛋白水平。
miR-497 可能在乳腺癌中作为一种肿瘤抑制基因发挥作用。在细胞中过表达 miR-497 可观察到细胞生长受到抑制、迁移和侵袭受到抑制以及 G1 期细胞周期阻滞，可能通过靶向 cyclin E1 发挥作用。这些结果表明，miR-497 可作为治疗乳腺癌的治疗靶点。
