BackgroundHigh expression of the RNA-binding motif protein 3 (RBM3) has previously been described as a favorable clinicopathological factor in several cancers, including ovarian cancer, colorectal cancer, prostate cancer, and breast cancer. The aim of this study was to examine the prognostic implications of RBM3 expression in gastric cancer.Material/MethodsImmunohistochemical analysis of RBM3 expression from 123 patients showed that upregulated RBM3 was mainly found in intestinal-type (n=78, case=59) cancer compared to diffuse-type (n=15, case=8) and mixed-type (n=30, case=17). There were no significant differences in RBM3 expression in subgroups of clinicopathological parameters. RBM3 expression was strongly associated with p53 but not with Ki-67. Cox univariate analysis revealed that high RBM3 expression was closely associated with prolonged overall survival time (HR 0.504, 95% CI: 0.300–0.845, P=0.009). Multivariate analysis remained supporting these associations when adjusted for age, sex, tumor size, differentiation grade, TNM stage, lymphatic invasion, and Ki-67 and p53 expression (HR 0.541, 95% CI: 0.308–0.952, P=0.033), where Lauren grade was not included. Lauren grade was the only factor with independent prognostic significance in a model adjusted for all factors. These results were confirmed by Kaplan-Meier analysis.ResultsTherefore, together with the upregulated RBM3 expression observed in intestinal-type of Lauren grade, we suggest that upregulation of RBM3 is partially responsible for the favorable overall survival in cases with intestinal Lauren grade, which is demonstrated by the box diagram and Kaplan-Meier analysis. Our results showed that high RBM3 expression in gastric cancer is mainly found in intestinal-type of Lauren grade and is associated with longer overall survival time.ConclusionWe found that RBM3 is a potential biomarker of good prognosis and deserves further validation.

Purpose: Gastric cancer (GC) is one of the most frequent tumors with high mortality rate, worldwide. A proper understanding of the mechanism  underlying its progression is required for its diagnosis and development of novel treatment option. MicroRNAs are associated with the development and advancement of different types of cancer, including GC. The current research was aimed at investigating the molecular and biological function of miR-148a-3p in GC development.Methods: A human normal gastric epithelial cell line, GES-1 (control) as well as four GC cell lines (NUGC-4, SNU-520, STKM-2 and MKN-74) were employed for the study. MiR-148a-3p and ATP6AP2 expression levels in GC cell lines were examined by RT-qPCR technique. Transfection procedure was used to upregulate miR-148a-3p expression in the MKN-45 cell line. MTT assay was utilized to evaluate cell viability in GC cell lines. The molecular interaction between miR-148a-3p and ATP6AP2 was predicted using bioinformatics system and the prediction was then validated by luciferase reporter assay.Results: Expression levels of miR-148-3p was low, whilst that of ATP6AP2 was high in GC cell lines. MiR-148a-3p overexpression resulted in the reduction of cell viability in GC cell lines. More so, it was confirmed that miR-148-3p, as a post-transcriptional regulator inhibited ATP6AP2 expression by having a negative association with it in GC cells. More so, ATP6AP2 was found to be a direct target of miR-148a-3p.Conclusion: Our results revealed that miR-148a-3p plays a crucial function in GC development through targeting ATP6AP2. This finding could be explored in the discovery of new therapeutic approaches for GC treatment. Keywords: ATP6AP2, Cell viability, Gastric cancer, miR-148a-3p, Progression