miR-33a inhibits cell growth in renal cancer by downregulation of MDM4 expression.

MicroRNA-33a (miR-33a) plays the role of the tumor suppressor gene by regulating the expression level of downstream genes. However, the effects of miR-33a in renal cell cancer (RCC) remain unknown. Our study was designed to investigate the expression level and potential function of miR-33a in RCC. RT-qPCR was applied to measure the levels of miR-33a in RCC tissues and cell lines. Western blotting and luciferase reporter assay were used to detect the relationship between miR-33a and Mouse double minute 4 (MDM4) in RCC cells. CCK-8 and flow cytometry were applied to detected cell viability and cell cycle. Animal models and TUNEL assay were applied to detect the effect of miR-33a on the growth of RCC and cell apoptosis. We found that the levels of miR-33a were significantly decreased in RCC tissues and cell lines. Moreover, the low expression of miR-33a in RCC patients indicated a shorter overall survival (OS). Notably, MDM4 as a direct target of miR-33a in RCC, the expression level of MDM4 was significantly increased in RCC cells group than the control group. Furthermore, miR-33a overexpression significantly inhibited RCC cells growth than the control group, while the inhibitory effects of miR-33a were reversed upon the overexpression of MDM4. Luciferase reporter assays showed that there was a direct interaction between miR-33a and 3' UTR of MDM4 mRNA. In vivo, tumor volumes and weight were significantly decreased in the transfected miR-33a mimics group than the control group. Taken together, our study indicates that miR-33a inhibits RCC cell growth by targeting MDM4.

Jiang K ，Sun F ，Zhu J ，Luo G ，Ban Y ，Zhang P ... -  《Molecular Genetics & Genomic Medicine》

MicroRNA-99a induces G1-phase cell cycle arrest and suppresses tumorigenicity in renal cell carcinoma.

Cui L ，Zhou H ，Zhao H ，Zhou Y ，Xu R ，Xu X ，Zheng L ，Xue Z ，Xia W ，Zhang B ，Ding T ，Cao Y ，Tian Z ，Shi Q ，He X ... -  《BMC CANCER》

miR-1293 Suppresses Tumor Malignancy by Targeting Hydrocyanic Oxidase 2: Therapeutic Potential of a miR-1293/Hydrocyanic Oxidase 2 Axis in Renal Cell Carcinoma.

Liu XL ，Pan WG ，Li KL ，Mao YJ ，Liu SD ，Zhang RM ... -  《-》

Effects of MDM4 Gene Regulation by miR-34a on LOVO Cell Proliferation.

This study aims to investigate the effects of regulation of murine double minute protein4 (MDM4) expression by microRNA (miR)-34a on the proliferation of colorectal cancer LOVO cells. Prediction results obtained using a gene microarray showed that MDM4 is a specific miR-34a target gene. The interaction between miR-34a and the 3'-untranslated region (UTR) of MDM4 was detected using a luciferase reporter system. The effect of miR-34a on MDM4 protein expression was detected by Western blotting, and the effect of miR-34a transfection on LOVO cell proliferation was detected using an MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay and flow cytometry. The luciferase activity in LOVO cells after addition of pmirGLO-UTR+miR-34a mimic was only 44% of that obtained with pmirGLO-UTR+miR-34a (p<0.01), and the luciferase activity in LOVO cells after addition of pmir-GLO-mutUTR+miR-34a was 94% of that observed after pmirGLO-UTR+miR-34a addition (p=0.57). These results indicated that miR-34a interacted with the 3'-UTR of MDM4. Results of Western blotting revealed that MDM4 protein expression level in LOVO cells after addition of miR-34a mimic was 29% that of non-treated LOVO cells (p<0.05), indicating that miR-34a negatively regulates MDM4 protein expression. The growth rate of LOVO cells with miR-34a overexpression was significantly reduced compared with that of non-treated LOVO cells (p<0.05), indicating that miR-34a overexpression inhibits LOVO cell proliferation. miR-34a negatively regulates MDM4 gene expression to inhibit LOVO cell proliferation.

Li S ，Pei Y ，Zhang W ，Sun L ，Jiang M ，Shang G ，Niu S ，Ma Z ... -  《-》

MicroRNA-200b is downregulated and suppresses metastasis by targeting LAMA4 in renal cell carcinoma.

Metastasis is the primary cause of tumor death in renal cell carcinoma (RCC). Improved diagnostic markers of metastasis are critically needed for RCC. MicoRNAs are demonstrated to be stable and significant biomarkers for several malignancies. In this study, we aimed to explore the metastasis related microRNAs and its mechanism in RCC. The relationship between microRNAs expression and prognosis and metastasis of RCC patients were explored by data mining through expression profiles from The Cancer Genome Atlas (TCGA). A total of 80 RCC tissues and adjacent normal kidney tissues were obtained from Department of Urology, Peking University First Hospital. Expression of microRNA-200b (miR-200b) in RCC tissues and cell lines were determined by bioinformatic data mining and quantitative real-time PCR (qRT-PCR). The effects of miR-200b on cell proliferation, migration and invasion were determined by cell counting kit-8 and colony formation assay, wound healing assay and Boyden chamber assay. Mouse cell-derived xenograft and patient-derived xenograft model were also performed to evaluate the effects of miR-200b on tumor growth and metastasis in vivo. The molecular mechanism of miR-200b function was investigated using bioinformatic target predication and high-throughput cDNA sequencing (RNA-seq) and validated by luciferase reporter assay, qRT-PCR, Western blot and immunostaining in vitro and in vivo. Our findings indicates that miR-200b is frequently downregulated and have potential utility as a biomarker of metastasis and prognosis in RCC. Interestingly, ectopic expression of miR-200b in the Caki-1 and OSRC-2 cell lines suppresses cell migration and invasion in vitro as well as tumor metastases in vivo. However, miR-200b has no effect on cell proliferation in vitro and tumor growth in vivo. In addition, bioinformatics target predication and RNA-seq results reveals that Laminin subunit alpha 4 (LAMA4) is one target of miR-200b and significantly inhibited by miR-200b in vitro and in vivo. These results demonstrate a previously undescribed role of miR-200b as a suppressor of tumor metastasis in RCC by directly destabilizing LAMA4 mRNA.

Li Y ，Guan B ，Liu J ，Zhang Z ，He S ，Zhan Y ，Su B ，Han H ，Zhang X ，Wang B ，Li X ，Zhou L ，Zhao W ... -  《EBioMedicine》