miR-4286 functions in osteogenesis and angiogenesis via targeting histone deacetylase 3 and alleviates alcohol-induced bone loss in mice

Objectives

Alcohol consumption is one of the leading factors contributing to premature osteopenia. MicroRNA (miRNA) coordinates a cascade of anabolic and catabolic processes in bone homeostasis and dynamic vascularization. The aim was to investigate the protective role of miR‐4286 in alcohol‐induced bone loss and its mechanism.

Materials and Methods

The effect of miR‐4286 and alcohol on bone mesenchymal stem cells (BMSCs) and human umbilical vein endothelial cells (HUVECs) was explored via multiple in vitro assays, including cell proliferation, QPCR, Western blot, osteogenesis, angiogenesis etc miR‐4286 directly regulated HDAC3 was investigated by luciferase reporter assay, and the function of HDAC3 was also explored in vitro. Moreover, alcohol‐induced bone loss in mice was established to reveal the preventive effect of miR‐4286 by radiographical and histopathological assays.

Results

In vitro, ethanol dramatically inhibited the proliferation and osteogenesis of BMSCs, and substantially impaired the proliferation and vasculogenesis of HUVECs. However, a forced overexpression of miR‐4286 within BMSCs and HUVECs could largely abolish inhibitory effects by alcohol. Furthermore, alcohol‐induced inhibition on osteogenic and vasculogenic functions was mediated by histone deacetylase 3 (HDAC3), and dual‐luciferase reporter assay showed that HDAC3 was the direct binding target of miR‐4286. In vivo, micro‐CT scanning and histology assessment revealed that miR‐4286 could prevent alcohol‐induced bone loss.

Conclusions

We firstly demonstrated that miR‐4286 might function via intimate osteogenesis‐angiogenesis pathway to alleviate alcohol‐induced osteopenia via targeting HDAC3.

miR-4286 is Involved in Connections Between IGF-1 and TGF-β Signaling for the Mesenchymal Transition and Invasion by Glioblastomas

The insulin-like growth factor (IGF)-1 and transforming growth factor (TGF)-β signal pathways are both recognized as important in regulating cancer prognosis, such as the epithelial-to-mesenchymal transition (EMT) and cell invasion. However, cross-talk between these two signal pathways in glioblastoma multiforme (GBM) is still unclear. In the present study, by analyzing data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GSE) 4412, GBM patients with higher IGF-1 levels exhibited poorer survival. Genes positively correlated with IGF-1 were enriched in EMT and TGF-β signal pathways. IGF-1 treatment enhanced mesenchymal marker expressions and GBM cell invasion. A significant positive correlation was observed for IGF-1 with TGF-β1 (TGFB1) or TGF-β receptor 2 (TGFBR2), both of which participate in TGF-β signaling and are risk genes in the GBM process. IGF-1 stimulation promoted both TGFB1 and TGFBR2 expressions. LY2157299, a TGF-β signaling inhibitor, attenuated IGF-1-enhanced GBM cell invasion and mesenchymal transition. By analyzing IGF-1-regulated microRNA (miR) profiles, miR-4286 was found to be significantly downregulated in IGF-1-treated cells and could be targeted to both TGFB1 and TGFBR2. Overexpression of miR-4286 significantly attenuated expressions of the IGF-1-mediated mesenchymal markers, TGFB1 and TGFBR2. Using kinase inhibitors, only U0126 treatment showed an inhibitory effect on IGF-1-reduced miR-4286 and IGF-1-induced TGFB1/TGFBR2 expressions, suggesting that MEK/ERK signaling is involved in the IGF-1/miR-4286/TGF-β signaling axis. Finally, our results suggested that miR-4286 might act as a tumor suppressive microRNA in inhibiting IGF-1-enhanced GBM cell invasion. In conclusion, IGF-1 is connected to TGF-β signaling in regulating the mesenchymal transition and cell invasion of GBM through inhibition of miR-4286. Our findings provide new directions and mechanisms for exploring GBM progression.

MicroRNA-4286 promotes cell proliferation, migration, and invasion via PTEN regulation of the PI3K/Akt pathway in non-small cell lung cancer

It is well-known that phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a tumor suppressor which negatively regulates PI3K/AKT signaling and is activated widely in non-small cell lung cancers (NSCLC). However, genetic alterations in PTEN genes are rare, suggesting an undefined mechanism(s) for their suppression. Notably, growing evidence indicates that PTEN can be regulated by microRNAs involved in cancer progression. In this study, we discover that the miR-4286 is overexpressed in NSCLC and negatively regulates the expression of PTEN. Furthermore, we found that miR-4286 reduces PTEN expression by directly binding to PTEN 3'-untranslated region (UTR), thereby inhibiting NSCLC cell proliferation and mobility. Moreover, mechanistic investigations revealed that miR-4286 overexpression was a result of PTEN-mediated activation of the PI3K/AKT pathway. Taken together, our findings elucidate that miR-4286 promotes the tumorigenesis of NSCLC by interacting with PTEN. This miR-4286-mediated upregulation of PTEN might lead to new therapeutic strategies for NSCLC.