MicroRNA-148a Suppresses Tumor Cell Invasion and Metastasis by Downregulating ROCK1 in Gastric Cancer

Abstract

Purpose: MicroRNAs (miRNA) have been documented playing a critical role in cancer development and progression. In this study, we investigate the role of miR-148a in gastric cancer metastasis.Experimental Design: We examined miR-148a levels in 90 gastric cancer samples by qRT-PCR and analyzed the clinicopathologic significance of miR-148a expression. The gastric cancer cells stably expressing miRNA-148a were analyzed for migration and invasion assays in vitro and metastasis assays in vivo; the target genes of miR-148a were further explored.Results: We found that miR-148a expression was suppressed by more than 4-fold in gastric cancer compared with their corresponding nontumorous tissues, and the downregulated miR-148a was significantly associated with tumor-node-metastasis (TNM) stage and lymph node-metastasis. Functional assays showed that overexpression of miR-148a suppressed gastric cancer cell migration and invasion in vitro and lung metastasis formation in vivo. In addition, overexpression of miR-148a in GC cells could reduce the mRNA and protein levels of ROCK1, whereas miR-148a silencing significantly increased ROCK1 expression. Luciferase assays confirmed that miR-148a could directly bind to the 2 sites of 3 0 untranslated region of ROCK1. Moreover, in gastric cancer tissues, we observed an inverse correlation between miR-148a and ROCK1 expression. Knockdown of ROCK1 significantly inhibited gastric cancer cell migration and invasion resembling that of miR-148a overexpression. We further found that ROCK1 was involved in miR-148a-induced suppression of gastric cancer cell migration and invasion. Conclusions: miR-148a functions as a tumor metastasis suppressor in gastric cancer, and downregulation of miR-148a contributes to gastric cancer lymph node-metastasis and progression. miR-148a may have a therapeutic potential to suppress gastric cancer metastasis. Clin Cancer Res; 17(24); 7574-83. Ó2011 AACR.

ROCK2/rasHa co-operation induces malignant conversion via p53 loss, elevated NF-κB and tenascin C-associated rigidity, but p21 inhibits ROCK2/NF-κB-mediated progression

“…These papilloma data thus link NF-κβ with increased DNA mutations/chromosomal instability 25,39 following p53 loss and associated p21 inhibition 47 [below]; and indirectly link ROCK2-mediated NF-κβ to stromal remodelling 25 thus accounting for effects previously observed on expression of ECM molecules such as tenascin C. 48,49 One consequence of p53 loss leading to an altered matrix may involve downregulated microRNAs, 34 such as miR-200 which regulates cell-cell adhesion molecules 35 and effected ROCK signalling in gastric cancer. 36 Of note, p53-mediated miR-200 expression depended upon AKT levels, 37 consistent with p53 loss driving malignant conversion in trigenic HK1.ras/fos/Pten flx carcinogenesis. 20 Early NF-κβ expression coupled to p53 down regulation in K14.ROCK er /HK1.ras 1205 papillomas 25,26 would account for increased proliferation, possibly via the NF-κβ responsive element regulating cyclin D 43 and, in sync with ROCK2/ras signalling, 12 add to the increasing pool of cycling cells susceptible to DNA damage/chromosomal re-arrangements.…”

“…loss and the lack of DNA repair would give rise to additional mutations in highly proliferative cells giving a susceptibility to malignant conversion. 32,33 Indeed, as outlined below, these K14.ROCK er /HK1.ras 1205 data suggest a mechanism involving p53 loss which links ROCK2-associated NF-κβ deregulation to the matrix remodelling that drives progression [34][35][36][37] when coupled to GSK3β/β-catenin/WNT signalling effects. 5 20,23,41 All wdSCCs exhibited persistent basal-layer p21 expression, which exactly paralleled K14.ROCK er /pMypt1 expression suggesting that increased p21 is a common response to ras/ROCK er /ROCK2 activities.…”

Characterization of exosomal RNAs derived from human gastric cancer cells by deep sequencing

“…36 Generally, miR-148a functions as a tumor suppressor in cancer cells. [33][34][35][36] However, in most studies, miR-148a was detected in specimens of tissues or cell lines. There is limited research involving exosomes containing miR-148a.…”

miRNA-145 Targets v-ets Erythroblastosis Virus E26 Oncogene Homolog 1 to Suppress the Invasion, Metastasis, and Angiogenesis of Gastric Cancer Cells

“…For in vivo experimental metastasis assay, 0.4 Â 10 6 cancer cells (per mouse, n ¼ 6 for each group) were transplanted into peripheral circulation of 5-week-old male nude mice through the lateral tail vein (24). After 8 weeks, mice were dissected to determine the number of metastatic colonies within the lungs (24).…”

“…After 8 weeks, mice were dissected to determine the number of metastatic colonies within the lungs (24).…”