MicroRNA-548a-5p promotes proliferation and inhibits apoptosis in hepatocellular carcinoma cells by targeting Tg737.

AIM: To investigate whether Tg737 is regulated by microRNA-548a-5p (miR-548a-5p), and correlates with hepatocellular carcinoma (HCC) cell proliferation and apoptosis. METHODS: Assays of loss of function of Tg737 were performed by the colony formation assay, CCK assay and cell cycle assay in HCC cell lines. The interaction between miR-548a-5p and its downstream target, Tg737, was evaluated by a dual-luciferase reporter assay and quantitative real-time polymerase chain reaction. Tg737 was then up-regulated in HCC cells to evaluate its effect on miR-548a-5p regulation. HepG2 cells stably overexpressing miR-548a-5p or miR-control were also subcutaneously inoculated into nude mice to evaluate the effect of miR-548a-5p up-regulation on in vivo tumor growth. As the final step, the effect of miR-548a-5p on the apoptosis induced by cisplatin was evaluated by flow cytometry. RESULTS: Down-regulation of Tg737, which is a target gene of miR-548a-5p, accelerated HCC cell proliferation, and miR-548a-5p promoted HCC cell proliferation in vitro and in vivo. Like the down-regulation of Tg737, overexpression of miR-548a-5p in HCC cell lines promoted cell proliferation, increased colony forming ability and hampered cell apoptosis. In addition, miR-548a-5p overexpression increased HCC cell growth in vivo. MiR-548a-5p down-regulated Tg737 expression through direct contact with its 3' untranslated region (UTR), and miR-548a-5p expression was negatively correlated with Tg737 levels in HCC specimens. Restoring Tg737 (without the 3'UTR) significantly hampered miR-548a-5p induced cell proliferation, and rescued the miR-548a-5p induced cell proliferation inhibition and apoptosis induced by cisplatin. CONCLUSION: MiR-548a-5p negatively regulates the tumor inhibitor gene Tg737 and promotes tumorigenesis in vitro and in vivo, indicating its potential as a novel therapeutic target for HCC.

FTY720 enhances osteogenic differentiation of bone marrow mesenchymal stem cells in ovariectomized rats.

Sphingosine-1-phosphate and its structural analog FTY720 (fingolimod) are important in the inhibition of osteoclast differentiation and bone resorption, however, it remains unknown whether they enhance osteogenic differentiation of the bone marrow mesenchymal stem cells (BM­MSCs). The present study investigated the effect of FTY720 on the osteogenic differentiation of BM­MSCs from the femurs of the ovariectomized (OVX) rats. Three different concentrations (1, 10 and 100 nM) of FTY720 were demonstrated to markedly upregulate mRNA expression levels of Runt­related transcription factor 2 (Runx2) and Sp7 transcription factor (Sp7) at 2 weeks, and alkaline phosphatase (ALP) at 3 weeks. The osteocalcin (OCN) expression was similar at weeks 2 and 3. The protein expression levels of Runx2, Sp7, OCN and ALP induced by three different concentrations of FTY720 were higher than those in the control groups at 3 weeks in the OVX and sham groups. The findings of the current study suggested a beneficial effect of FTY720 on bone formation in OVX rats, and provided a potential therapeutic method of FTY720 to prevent alveolar bone resorption in patients with post­menopausal osteoporosis.

Curcumin regulates hepatoma cell proliferation and apoptosis through the Notch signaling pathway.

Curcumin has become a compound of interest for its antioxidant and anti-neoplastic properties. This study sought to determine the effect of curcumin administration on cell proliferation and apoptosis in hepatoma cells. SMMC-7721 hepatoma cells were treated with 10, 30, or 90 µM curcumin solution, with DMEM alone (negative control), or with 20 mg/L fluorouracil (positive control). MTT colorimetry detected significant differences in the rates of cell proliferation inhibition following curcumin treatment, with increasing inhibition accompanying increasing doses of curcumin (P < 0.05), compared to the negative control. Similarly, flow cytometry revealed significant differences in the numbers of apoptotic cells following curcumin treatment: increasing doses of curcumin produced increases in the numbers of apoptotic cells (P < 0.05). To determine whether curcumin exerts these effects by altering the Notch signaling pathway, a phenomenon reported for other cancers, relative expression of Notch1 mRNA and protein were determined in curcumin-treated cells. Both mRNA and protein expression of Notch1 decreased with increasing curcumin dose (P < 0.05). Thus, curcumin appears to inhibit proliferation and induce apoptosis in hepatoma cells by altering the Notch signaling pathway.