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Purpose: MicroRNA-939 (miR-939) has crucial roles in several types of human cancer. However, the expression profile and precise functions of miR-939 in prostate cancer (PCa) are still unclear. This study aimed to determine miR-939 expression in PCa and explore its roles in PCa tumorigenesis. Methods: miR-939 expression was determined in PCa tissues and cell lines using reverse transcription–quantitative polymerase chain reaction. Cell Counting Kit-8, colony formation, and flow cytometric assays were used to determine the role of miR-939 in PCa cell proliferation and apoptosis in vitro, whereas a tumor xenograft model was generated to evaluate the effect of miR-939 on tumor growth in vivo. Transwell assays were performed to investigate whether miR-939 affects the migration and invasiveness of PCa cells. Results: miR-939 was found to be downregulated in PCa tissues and cell lines, and this downregulation was significantly correlated with tumor stage and lymphatic metastasis. Patients with PCa exhibiting low miR-939 expression had shorter overall survival than those exhibiting high miR-939 expression. Exogenous miR-939 expression suppressed PCa cell proliferation, colony formation, migration, and invasion in vitro; enhanced apoptosis in vitro; and decreased tumor growth in vivo. Investigation of the underlying molecular mechanisms revealed hepatoma-derived growth factor (HDGF) as a direct target gene of miR-939 in PCa. HDGF was found to be significantly upregulated in PCa tissues, and its expression was inversely correlated with miR-939 expression. HDGF silencing and miR-939 upregulation showed similar effects in PCa. Restored HDGF expression counteracted the tumor-suppressive activity of miR-939 overexpression in PCa cells. Furthermore, ectopic miR-939 expression inhibited the WNT/β-catenin pathway activation in PCa both in vitro and in vivo by downregulating HDGF. Conclusion: miR-939 functions as a tumor suppressor during PCa tumorigenesis by directly targeting HDGF and deactivating the WNT/β-catenin pathway, suggesting the miR-939/HDGF/WNT/β-catenin pathway as an effective target for PCa therapy. [ABSTRACT FROM AUTHOR]

Background: Liver cancer was the fourth leading cause of cancer-related death in 2015. Hepatocellular carcinoma (HCC) is the most common type of liver cancer. miR-1-3p plays important roles in cancer, including prostate, bladder, lung cancer, and colorectal carcinoma. The function of miR-1-3p in HCC remains poorly understood. Methods: qRT-PCR was performed to detect the miR-1-3p expression in HCC cell lines (HCCLM3, Hep3B, Bel-7404, SMMC-7721) and the normal human hepatic cell line (LO2). HCCLM3 and Bel-7404 cells were transfected with miR-1-3p mimic or scramble control followed by water-soluble tetrazolium salt (WST-1) assay. Western bolt analysis was performed to determine the protein levels. TargetScan7.1 (http://www.targetscan.org/vert%5f71/) was used to predict the potential targets of miR-1-3p. SRY (sex determining region Y)-box 9 (SOX9), which has been previously shown to play an important role in HCC, was found to be a target of miR-1-3p. Luciferase reporter assay was used to explore the targeting of miR-1-3p on SOX9. For in vivo tumorigenesis assay, HCCLM3 cells with stable overexpression of miR-1-3p or control plasmid were injected subcutaneously into the flank of the SCID mice and animals were monitored for tumor growth. Results: miR-1-3p was significantly downregulated in HCC cell lines (HCCLM3, Hep3B, Bel-7404, and SMMC-7721) compared to normal human hepatic cell line (LO2). Overexpression of miR-1-3p significantly inhibited the proliferation and induced apoptosis in HCCLM3 and Bel-7474 cells. SOX9 was a direct target of miR-1-3p in HCC cells. Inhibition of SOX9 significantly inhibited the proliferation of HCCLM3 and Bel-7474 cells. In vivo, overexpression of miR-1-3p decreased tumor volume in a xenograft model. Conclusion: These results highlight the role of miR-1-3p in HCC. Overexpression of miR-1-3P inhibited the proliferation of HCC at least partly due to the regulation of SOX9. miR-1-3p may be a promising therapeutic candidate for HCC. [ABSTRACT FROM AUTHOR]