Non-coding RNAs PROX1-AS1 and miR-647: Potential Interaction and Prognostic Value in Gastric Cancer.

[BACKGROUND] Gastric cancer (GC) remains one of the most common malignancies and the third cause of cancer-related deaths worldwide. Non-coding RNAs (ncRNAs), including microRNAs and long ncRNAs, can contribute to the pathogenesis and progression of GC and therefore could be its potent diagnostic and prognostic biomarkers. The aim of our work was to estimate the expression of PROX1- AS1 (Prospero Homeobox 1 Antisense RNA 1) and miR-647 (microRNA-647) in GC and investigate their potential interaction and clinical significance.

[METHODS] The study included tumor and adjacent non-tumor tissues from 110 GC patients and plasma samples from 65 GC patients; 38 sectional normal gastric tissue samples and 49 plasma samples of healthy donors were included as controls. Expression levels of both ncRNAs were quantified in all samples by using real-time polymerase chain reaction (RT-PCR) and their possible correlations with the clinical and pathological characteristics of patients were analyzed. A potential inverse correlation between PROХ1-AS1 and miR-647 expression was addressed by in vitro experiments in a panel of cancer cell lines.

[RESULTS] The expression of PROX1-AS1 and miR-647 was not significantly different in tissues of GC patients and sectional normal gastric tissue samples. However, they have demonstrated a negative correlation both in the tumor and the adjacent nontumor tissue of GC patients. PROX1-AS1 expression was significantly decreased in GC tissues, whereas the miR-647 expression was increased. The expression of the ncRNAs was associated with clinical and pathological characteristics of GC patients. The overexpression of miR-647 led to a significant decrease in PROX1-AS1 expression in five cancer cell lines, including the GC cell line SNU-1.

[CONCLUSION] We have demonstrated a negative correlation between PROX1-AS1 and miR-647 in both GC tissues and the cancer cell lines. In addition, expression of both ncRNAs was associated with the primary tumor size. Therefore, these ncRNAs might have potential prognostic value.