MicroRNA-503 acts as a tumor suppressor in osteosarcoma by targeting L1CAM

miR-503 suppresses tumor cell proliferation and metastasis by directly targeting RNF31 in prostate cancer

Microarray data analyses were performed to search for metastasis-associated oncogenes in prostate cancer (PCa). RNF31 mRNA expressions in tumor tissues and benign prostate tissues were evaluated. The RNF31 protein expression levels were also analyzed by western blot and immunohistochemistry. Luciferase reporter assays were used to identify miRNAs that can regulate RNF31. The effect of RNF31 on PCa progression was studied in vitro and in vivo. We found that RNF31 was significantly increased in PCa and its expression level was highly correlated with seminal vesicle invasion, clinical stage, prostate specific antigen (PSA) level, Gleason score, and BCR. Silence of RNF31 suppressed PCa cell proliferation and metastasis in vitro and in vivo. miR-503 can directly regulate RNF31. Enforced expression of miR-503 inhibited the expression of RNF31 significantly and the restoration of RNF31 expression reversed the inhibitory effects of miR-503 on PCa cell proliferation and metastasis. These findings collectively indicated an oncogene role of RNF31 in PCa progression which can be regulated by miR-503, suggesting that RNF31 could serve as a potential prognostic biomarker and therapeutic target for PCa.

miR-503 suppresses metastasis of hepatocellular carcinoma cell by targeting PRMT1

Accumulating evidence indicates that microRNAs function as oncogenes or tumor suppressor genes in human cancer. MiR-503 is deregulated in various human cancers and has been associated with hepatocellular carcinoma (HCC) progression. However, the underlying mechanisms of miR-503 involvement in the development and progression of HCC remains poorly understood. In the present study, we report that miR-503 suppresses cell metastasis in HCC through targeting the protein arginine methyl transferase 1 (PRMT1) mRNA. Notably, we identified that miR-503 was able to target 3'-untranslated region (3'-UTR) of PRMT1 mRNA by luciferase reporter gene assays. Then, we revealed that miR-503 was able to reduce the expression of PRMT1 at the levels of mRNA and protein using RT-PCR and Western blotting analysis. The expression levels of miR-503 were negatively related to those of PRMT1 mRNA in clinical HCC tissues. In terms of function, transwell and wound healing assays demonstrated that the miR-503 remarkably inhibited invasion and migration of HCC cells, which was reversed by overexpressed PRMT1. Furthermore, exogenous expression of miR-503 dramatically suppressed epithelial-mesenchymal transition (EMT) via PRMT1 in HCC cells. In conclusion, we denomstrated PRMT1 as a novel target gene of miR-503 and miR-503-mediated PRMT1 could also emerge as a potential important biomarker for HCC.

MiR-503 inhibited cell proliferation of human breast cancer cells by suppressing CCND1 expression

Breast cancer is one of the most common malignancies and a major cause of cancer-related mortality all over the world. A growing body of reports revealed that microRNAs play essential roles in the progression of cancers. Aberrant expression of miR-503 has been reported in several kinds of cancer. The aim of the current study was to elucidate the role of miR-503 in the pathogenesis of breast cancer. In the present study, our results suggested that miR-503 expression was markedly downregulated in breast cancer tissues and cells. Overexpression of miR-503 in breast cancer cell lines reduced cell proliferation through inducing G0/G1 cell cycle arrest by targeting CCND1. Together, our findings provide new knowledge regarding the role of miR-503 in the progression of breast cancer and indicate the role of miR-503 as a tumor suppressor microRNA (miRNA) in breast cancer.

Up-Regulation of MiR-300 Promotes Proliferation and Invasion of Osteosarcoma by Targeting BRD7

Increasing reports suggest that deregulated microRNAs (miRNAs) might provide novel therapeutic targets for cancers. However, the expression and function of miR-300 in osteosarcoma is still unknown. In our study, we found that the expression of miR-300 was up-regulated in osteosarcoma tissues and cells compared with paired adjacent non-tumor bone tissues and osteoblastic cells using RT-qPCR. The enforced expression of miR-300 could promote cell proliferation, invasion and epithelial-mesenchymal transition (EMT). Moreover, we identified that bromodomain-containing protein 7 (BRD7), a new tumor suppressor gene, was a direct target of miR-300. Ectopic expression of BRD7 could significantly inhibit miR-300-promoted proliferation, invasion and EMT. Therefore, our results identify an important role for miR-300 in osteosarcoma through regulating BRD7 expression.

P53 suppresses cell proliferation, metastasis, and angiogenesis of osteosarcoma through inhibition of the PI3K/AKT/mTOR pathway

OBJECTIVE

To investigate the role of P53 in the pathogenesis of osteosarcoma and the possible mechanism involved in it.

METHODS

The anti-proliferative effect of P53 was assessed using the cell counting Kit-8 assay. The migration and invasion potential were analyzed using wound-healing and transwell assays, respectively. The Matrigel capillary tube formation assay was performed to mimic in-vivo angiogenesis. Immunoblotting and immunofluorescence were used to observe protein levels and distribution of actin fibers. Finally, S2448p-mammalian target of rapamycin (mTOR) expression was detected on osteosarcoma tissues using immunohistochemistry.

RESULTS

Firstly, P53 potently inhibited cell proliferation in osteosarcoma cell line (MG63) and in human normal osteoblasts (hFOB1.19) in vitro at the IC50 ranged from 50 to 500 nmol/l. Then, an inhibitory effect of P53 on metastasis was observed in osteosarcoma cell line MG63, along with the cytoskeletal rearrangements and suppression of the phosphorylation of PI3K downstream factors including AKT and mTOR.

CONCLUSION

These results show that P53 suppresses cell proliferation and angiogenesis of osteosarcoma through inhibition of the PI3K/AKT/mTOR pathway, which might be an effective novel therapeutic candidate against osteosarcoma in the future.

Review of microRNA in osteosarcoma and chondrosarcoma

MicroRNAs (miRNAs) are small noncoding RNAs, which play a complex role in posttranscriptional gene expression and can theoretically be used as a diagnostic or prognostic tool, or therapeutic target for neoplasia. Despite advances in the diagnosis and treatment of skeletal sarcomas, including osteosarcoma and chondrosarcoma, much remains unknown regarding their underpinning molecular mechanisms. Given the recent increasing knowledge base of miRNA roles in neoplasia, both as oncogenes and tumor suppressor genes, this review will focus on the available literature regarding the expression profiles and potential roles of miRNA in skeletal sarcomas. Although this is an emerging field, miRNA profiling may be of use in clarifying competing diagnoses of skeletal sarcomas and possibly indicate patient risk of resistance to traditional chemotherapeutic agents. While detecting and targeting miRNAs is currently limited to experimental investigations, miRNA may be utilized for future clinical management of skeletal sarcomas.