MicroRNA-4463 facilitates the development of colon cancer by suppression of the expression of PPP1R12B

PURPOSE

In the present work, we investigated the expression pattern of miR-4463 in the non-metastasis and metastasis colorectal cancer (CRC) patients and its regulation axis.

METHODS

RT-qPCR assay was performed to assess miR-4463 expression in the serum and tissues of patients with non-metastasis and metastasis, and in the CRC cell lines. MTT assay, colony formation assay, transwell assay, and flow cytometry assay were used to examine the role of miR-4463 in CRC cell viability, proliferation, and migration. Bioinformatic analysis was used to identify the potential target gene of miR-4463, and the targeting relationship between miR-4463 and PPP1R12B was verified in vitro using dual luciferase assay. Western blotting assay was used to determine the protein level of the target gene PPP1R12B in CRC cells under the transfections of miR-4463 mimic, inhibitor and vectors overexpressing PPP1R12B.

RESULTS

miR-4463 was markedly increased in the non-metastasis CRC tissues, and increased even higher in the metastasis CRC tissues, while miR-4463 expression had no significant difference in serum from non-metastasis and metastasis CRC samples. Besides, miR-4463 was upregulated in CRC cell lines. Functionally, miR-4463 promoted CRC cell proliferation, migration, and inhibiting cell apoptosis. Further analysis revealed that the miR-4463/PPP1R12B axis was responsible for the role of this miRNA.

CONCLUSION

We reported the roles of miR-4463 in CRC proliferation and migration, supporting that miR-4463 could be a potential predictive diagnostic marker for colon cancer.

Suppression of miR-4463 promotes phenotypic switching in VSMCs treated with Ox-LDL

Vascular smooth muscle cell (VSMC) phenotypic switching is a hallmark of vascular remodeling that contributes to atherosclerotic diseases. MicroRNA 4463 (miR-4463) has been implicated in the development of arteriosclerosis obliterans, whereas the underlying mechanisms in VSMCs have not been fully addressed. In this study, we assessed whether miR-4463 is involved in the phenotypic switching process in VSMCs. Oxidized low-density lipoprotein (Ox-LDL, 50 mg/L) was used to simulate the oxidative stress condition, and miR-4463 expression in VSMCs was detected by a quantitative polymerase chain reaction. To determine the effect of Ox-LDL-mediated regulation of miR-4463 on the phenotypic switching of VSMCs, cell counting kit-8, cell migration assays, and cytoskeleton test were performed. After using specific antagonists of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), the relationship between miR-4463 and its downstream signaling proteins was explored. Ox-LDL induced oxidative stress to promote VSMC transformation from contraction to secretion, which clearly decreased the level of miR-4463. Then, downregulated miR-4463 enhanced the migration and phenotypic transformation of VSMCs and activated the phosphorylation of JNK and ERK; these effects were increased after Ox-LDL induction. As expected, inhibiting the two signaling proteins blocked the effect of the miR-4463 inhibitor combined with Ox-LDL. In addition, inhibition of miR-4463 led to the upregulation of basic fibroblast growth factor (bFGF) expression. The results of this study demonstrate that miR-4463 is a novel regulator of VSMC function in hypoxic conditions and modulates VSMC phenotypic switching via the JNK and ERK signaling pathways; bFGF may be the target gene of miR-4463.

Downregulation of MicroRNA-4463 Attenuates High-Glucose- and Hypoxia-Induced Endothelial Cell Injury by Targeting PNUTS

BACKGROUND/AIMS

Vascular complications are the main reasons for disability and mortality associated with type 2 diabetes mellitus (T2DM) and numerous microRNAs (miRNAs) are involved in this process. Our previous study demonstrated that miR-4463 was increased in the plasma of T2DM patients combined with arteriosclerosis of low extremity artery (ASO). However, the role of miR-4463 remains unclear.

METHODS

miR-4463 expression in the vascular tissues of patients with ASO and T2DM and in human umbilical vein endothelial cells (HUVECs) was detected by qPCR. Cell survival and apoptosis was analyzed via Cell Counting Kit-8 and flow cytometry assays, respectively. Protein expression was determined by Western blot and protein subcellular localization was detected with immunofluorescence. A dual-luciferase assay was used to elucidate the target gene of miR-4463.

RESULTS

miR-4463 was elevated in the vascular tissues of patients with T2DM and ASO. In HUVECs, both 25 mmol/L glucose (high glucose, HG) and hypoxia induced miR-4463 expression. Downregulation of miR-4463 promoted HUVEC survival and reduced cell apoptosis under HG and/or hypoxic conditions by facilitating the expression of protein phosphatase-1 nuclear targeting subunit (PNUTS), X-linked inhibitor of apoptosis protein (XIAP), p-AKT, p-Bad, increased the Bcl-2/Bax ratio, as well as downregulated cleaved caspase 3 expression. Mechanistically, we identified PNUTS as a direct target gene of miR-4463. Both the inhibition of AKT phosphorylation and silencing of PNUTS diminished the effect of miR-4463 on HUVEC apoptosis. Moreover, downregulation of miR-4463 enhanced PNUTS to enable PTEN nuclear localization, which resulted in AKT phosphorylation.

CONCLUSION

Our results suggest that downregulation of miR-4463 attenuates cell apoptosis by directly enhancing PNUTS expression to promote PTEN nuclear localization, subsequently activating AKT signaling pathway in HUVECs under HG and/ or hypoxic conditions.

MiR-4463 inhibits the migration of human aortic smooth muscle cells by AMOT

Aberrant vascular smooth muscle cell (VSMC) migration has been implicated in a variety of vascular disorders, while the signal pathways governing this process remain unclear. Here, we investigated whether miRNAs, which are strong post-transcriptional regulators of gene expression, could alter VSMC migration. We detected the expression of miR-4463 in the plasma of patients with atherosclerosis and in human aortic smooth muscle cells under hypoxia–ischemia condition, and investigated the migration effect and its downstream pathways. The results have shown that whether in clinical AS patients or hypoxic cells, the expression of miR-4463 was lower than that of normal group, then the number of migrating cells in the miR-4463 mimic intervention group was significantly decreased compared with the normal group and miR-4463 inhibitor instead. Furthermore, the expression of angiomotin (AMOT) in gastrocnemius muscle and femoral artery of patients was significantly higher than that of the control group. The protein level of AMOT in miR-4463 mimic intervention group was significantly decreased, and its level was reversed by inhibiting miR-4463. In summary, these results indicate that miR-4463 is a novel modulator of VSMC migration by targetting AMOT expression. Regulating miR-4463 or its specific downstream target genes in VSMCs may represent an attractive approach for the treatment of vascular diseases.

The potential value of microRNA-4463 in the prognosis evaluation in hepatocellular carcinoma

The purpose of this study is to measure the expression of microRNA-4463 and microRNA-6087 between normal persons and patients with hepatocellular carcinoma (HCC), and to clarify the meaning of them in the prognosis evaluation in HCC. Forty-five samples from healthy people and patients, who had been diagnosed with hepatocellular carcinoma before any treatment, were collected to study respectively. Real-time PCR was used to detect the expression of miRNA-4463 and miRNA-6087 in the serum of control group and hepatocellular carcinoma patients. The expression of miR-4463 in the serum of HCC patients was significantly higher than that in control group (P < 0.05), and the expression level was independent of gender, tumor size, cell types, stages, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL) and HBsAg status (P > 0.05). But there was a significant difference of different level of AFP in HCC (P < 0.05), and the difference between the group of AFP lower than 400 ug/l and the control group is statistically significant (P < 0.05). Besides, the survival time had showed a significant difference at the high and low expression levels (P < 0.05). But the expression level of miRNA-6087 was no difference in HCC and control group. The disorder of miRNA-4463 occurred in HCC, even the AFP level doesn't rises. What's more, patients who get the high level of miRNA-4463 seem to have a shorter survival time. And it contributes great to the prognostic evaluation. This is the first study to illustrate the potential significance of miRNA-4463 in the prognosis in HCC.