miR-335 directly, while miR-34a indirectly modulate survivin expression and regulate growth, apoptosis, and invasion of gastric cancer cells

Abstract

miR-335 and miR-34a are two microRNAs (miRNAs) usually downregulated in gastric cancer (GC). But, their exact regulative roles were not fully elucidated. In this study, we studied the association between miR-335 and/or miR-34a expression and overall survival of GC patients and explored the regulative role of miR-335 and -34a over survivin expression and GC cell growth and invasion. Fifty patients with GC were regularly followed up from 2011 to 2015. miRNA microarray was used to examine the expression trend of miRNAs in eight tumor tissue samples and adjacent normal tissue samples. The possible binding site between miR-335 and survivin messenger RNA (mRNA) was predicted using online database and verified using qRT-PCR, Western blot, and dual luciferase assay. The regulative role of miR-335 and miR-34a over GC cell growth, apoptosis, and invasion was studied using Cell Counting Kit-8 (CCK-8) assay, flow cytometry, and transwell assay, respectively. Among the GC patients, low miR-335 or miR-34a expression is associated with higher clinical stage and lymph node metastasis. Patients with low miR-335 or miR-34a had poor overall survival, while those with combined low miR-335 and miR-34a expression had even poorer overall survival. miR-335 can directly regulate survivin expression through binding to the 3'UTR, while miR-34a has indirect modulating effect. Both miR-335 and miR-34a could inhibit cell proliferation and invasion and enhance cell apoptosis. But, these effects are largely abrogated by overexpression of survivin without 3'UTR. Therefore, besides the targets identified in previous studies, miR-335 and miR-34a can also regulate GC cell growth, apoptosis, and invasion at least partly through survivin.

Dysregulation of miRNAs as a signature for diagnosis and prognosis of gastric cancer and their involvement in the mechanism underlying gastric carcinogenesis and progression

“…The low expression of tumor suppressors, miR‐1 and miR‐146a, was associated with vascular invasion, lymph node involvement, and distant metastasis, in addition to the poor prognosis of patients with GC. Downregulation of miR‐335 was determined to be appreciably associated with lymph node metastasis (LNM), invasion of lymphatic vessels, cell invasion, and metastasis via targeting of BCL‐w and SP1 . In addition, the tumor suppressors, miR‐125a and miR‐146a, are notably correlated with LNM, indicating that they should be prognostic elements of OS .…”

“…Downregulation of miR-335 was determined to be appreciably associated with lymph node metastasis (LNM), invasion of lymphatic vessels, cell invasion, and metastasis via targeting of BCL-w and SP1. 88,89 In addition, the tumor suppressors, miR-125a and miR-146a, are notably correlated with LNM, indicating that they should be prognostic elements of OS. 90,91 Furthermore, the relative level of miR-146a expression was an independent predictive factor for OS.…”

MicroRNA-335-5p and Gastrointestinal Tumors

“…However, gene-specific approaches suggest that miRNA-335-5p is downregulated in GC and clinically associated with advanced TNM stage and worse prognosis [5,33]. Functional studies have shown that exogenous expression of miRNA-335-5p deregulated many biological cell processes such as cell cycle, proliferation, apoptosis, migration, invasion, and metastasis [5,25,33,34] (Figure 2). Figure…”

“…Cellular processes by which miRNA-335-5p contributes to their regulation though of different target genes in gastric cancer cell lines. miRNA-335-5p inhibits tumorigenicity, cell cycle, proliferation, apoptosis, migration, invasion, and metastasis [5,25,33,34]. Abbreviations: CRKL, V-crk avian sarcoma virus CT10 oncogene homolog-like; CDH11, cadherin 11; PLAUR, plasminogen activator urokinase receptor; SP1, specificity protein 1; BCL-w, BCL2-like 2 (taken from Sandoval-Bórquez et al [5] with permission).…”

Relationship between ncRNAs and gastric cancer: meta-analysis

“…However, the pooled P values did not support these associations. The P values of the associations between the expression of mir-200c with lymph node metastasis and TNM stage (9, 10), mir-34a with lymph node metastasis (11,12), as well as mir-215 with tumor invasion depth (13,14) changed from less than 0.05 to more than 0.05 (Tab. 2).…”