Molecular mechanisms of miR‐1236 in the assessment of tumor lymphangiogenesis in human ovarian cancer patients

Abstract

Background Tumor lymphangiogenesis is a critical component in the progression of cancers and specific microRNAs have been reported to be implicated in this process. Recent studies revealed the involvement of miR‐1236 in lymphangiogenic signaling by targeting vascular endothelial growth factor receptor 3 (VEGFR3). However, the prognostic importance of miR‐1236 and its clinical relevance for lymphangiogenesis in ovarian cancer (OC) remains unclear. Methods The study included 52 ovarian tumors and 28 normal ovarian tissues. Quantitative real‐time PCR was utilized to analyze the VEGFR3, VEGF‐C, LYVE‐1 and PROX1 mRNA expression as well as miR‐1236. VEGFR3 protein expression was measured by immunohistochemistry staining. Immunohistochemistry for the podoplanin marker (D2‐40) was performed to measure lymphatic vessel density (LVD). In addition, diagnostic evaluation based on the receiver‐operating characteristic (ROC) curve was performed. The influence of miR‐1236 on overall survival was evaluated by Kaplan–Meier method. Results Here, we show that miR‐1236 expression was significantly decreased in ovarian tumors compared with control tissues (p < 0.001) and correlated with advanced clinical stage, lymph node metastasis, distant metastasis and patient survival (All P < 0.05). Moreover, in ovarian tumors, LVD as well as the gene expression of VEGFR3, VEGF‐C and LYVE‐1, but not PROX1, were found to be remarkably higher compared with control tissues. We also detected a more robust positive staining for VEGFR3 in OC tissues than in control tissues. Furthermore, our results demonstrated an inverse association of miR‐1236 expression with LVD, VEGFR3, LYVE‐1 and PROX1 expression in OC tissues. The ROC curve analysis indicated that miR‐1236 expression has the potential to be used as a diagnostic and prognostic biomarker in OC. Survival analysis further verified a lowered overall survival rate in patients with low miR‐1236 expression than in those with high expression. Conclusions Our results provide evidence for the translational involvement of miR‐1236 in the lymphangiogenesis of OC by regulating lymphangiogenesis‐related factors and support the clinical importance of miR‐1236 as a new diagnostic and prognostic biomarker for OC.