MiR-133 inhibits cell proliferation, migration, and invasion in gastric cancer cells by targeting JAK2

AIM

To investigate the role of miR-133 in the proliferation, migration, and invasion of gastric cancer (GC) cells, and to explore the underlying mechanism.

METHODS

The expression of miR-133 and JAK2 mRNA in tissues and cells was detected by qRT-PCR. AGS and MGC-803 cells were transfected with miR-133 mimic (miR-133 group), miR-133 inhibitor (miR-133 inhibitor group), nonspecific inhibitor (inhibitor-NC group), psiCHECK2-JAK2-3 UTR WT vector and miR-133 mimic (JAK2 WT group), psiCHECK2-JAK2-3 UTR MUT vector and miR-133 mimic (JAK2 MUT group), miR-133 mimic and JAK2 (miR-133 + JAK2 group), or miR-133 mimic and pc-DNA 3.1 (miR-133 + vector group) using a liposome-mediated method. Untransfected cells (miR-NC group) were also included as a control. The protein expression of JAK2 was detected by Western blot. Cell proliferation was detected by MTT assay. Cell migration and invasion were detected by Transwell assay. The luciferase activity was detected by double luciferase reporter assay.

RESULTS

Compared with human paracancerous tissues or normal gastric mucosal cells (GES-1), miR-133 was down-regulated in GC tissues and GC cells (AGS and MGC-803), and JAK2 was highly expressed in GC tissues and AGS and MGC-803 cells (P < 0.05). Overexpression of miR-133 or silencing JAK2 could inhibit cell proliferation, migration, and invasion in GC cells. JAK2 is a target of miR-133, and JAK2 could rescue the inhibitory effect of miR-133 on cell proliferation, migration, and invasion in GC cells.

CONCLUSION

MiR-133 could inhibit the proliferation, migration, and invasion of GC cells via mechanisms possibly related to targeting of JAK2, which will provide a new target for the clinical diagnosis and treatment of GC.

Tanshinone IIA ameliorates apoptosis of myocardiocytes by up-regulation of miR-133 and suppression of Caspase-9

To explore the potential protective effect of Tanshinone ⅡA on myocardial cell apoptosis and elucidate the underlying molecular mechanisms. The rat heart cell H9c2 was treated by either H₂O₂ or doxorubicin (DOX) to mimic oxidative stress and DNA damage conditions in vivo. Cell growth was monitored by optical microscope observation or CCK-8 counting kit. The relative expression of miR-133 and U6 snoRNA was semi-quantitated by RT-PCR or real-time PCR. Cell apoptosis was analyzed by flow cytometry with Annexin V/PI double staining. The microRNA binding sites were predicted by online bioinformatics tools. The regulatory effect of miR-133 on caspase-9 was measured by luciferase reporter assay. Apoptosis pathway factors were analyzed by immunoblotting. Our data demonstrated that Tanshinone ⅡA significantly ameliorated myocardial apoptosis induced by either H₂O₂ or DOX. The protective effect was likely mediated by up-regulation of miR-133. We further identified Caspase-9 as the target of miR-133. Tanshinone ⅡA treatment significantly reversed down-regulation of miR-133 under harsh conditions and in turn suppressed evoking of Caspase-9 and related apoptotic effectors, which consequently contributed to the improvement of myocardial injury. In conclusion, Tanshinone ⅡA ameliorated myocardial apoptosis via restoration of miR-133 and suppression Caspase-9 signaling cascade, which underlies its well-proven clinical benefit and warrants larger scale clinical applications.

MicroRNA-133 mediates cardiac diseases: Mechanisms and clinical implications

MicroRNAs (miRNAs) belong to the family of small non-coding RNAs that mediate gene expression by post-transcriptional regulation. Increasing evidence have demonstrated that miR-133 is enriched in muscle tissues and myogenic cells, and its aberrant expression could induce the occurrence and development of cardiac disorders, such as cardiac hypertrophy, heart failure, etc. In this review, we summarized the regulatory roles of miR-133 in cardiac disorders and the underlying mechanisms, which suggest that miR-133 may be a potential diagnostic and therapeutic tool for cardiac disorders.

MicroRNAs modulating angiogenesis: miR-129-1 and miR-133 act as angio-miR in HUVECs

The sprouting of new blood vessels by angiogenesis is critical in vascular development and homeostasis. Aberrant angiogenesis leads to enormous pathological conditions such as ischemia and cancer. MicroRNAs (also known as miRNAs or miRs) play key roles in regulation of a range of cellular processes by posttranscriptional suppression of their target genes. Recently, new studies have indicated that miRNAs are involved in certain angiogenic settings and signaling pathways use these non-coding RNAs to promote or suppress angiogenic processes. Herein, VEGFR2 and FGFR1 were identified as miR-129-1 and miR-133 targets using bioinformatic algorithms, respectively. Afterwards, using luciferase reporter assay and gene expression analysis at both mRNA and protein levels, VEGFR2 and FGFR1 were validated as miR-129-1 and miR-133 targets. In addition, we showed that miR-129-1 and miR-133 suppress angiogenesis properties such as proliferation rate, cell viability, and migration activity of human umbilical vein endothelial cells (HUVEC) in vitro. We conclude that these miRNAs can suppress key factors of angiogenesis by directly targeting them. These results have important therapeutic implications for a variety of diseases involving deregulation of angiogenesis, including cancer.

Impairment of growth of gastric carcinoma by miR-133-mediated Her-2 inhibition

Gastric carcinoma (GC) is a leading cause of cancer-related death in China. Dysregulation of microRNAs (miRNAs) has been shown to contribute to the development of GC, whereas the role of miR-133 in GC is unknown. Here, we analyzed the levels of miR-133 in GC tissues by reverse and quantitative transcription polymerase chain reaction (RT-qPCR). We overexpressed or inhibited miR-133 in GC cells. Cell growth was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and cell apoptosis was evaluated by fluorescence-activated cell sorting (FACS) analysis. Targeted genes were predicted by a bioinformatics algorithm and confirmed by a dual-luciferase reporter assay. We detected lower miR-133 levels in GC tissues compared with normal gastric tissue. Moreover, the low miR-133 levels were correlated with low survival rate. Overexpression of miR-133 inhibited cell growth and promoted apoptosis, while depletion of miR-133 increased cell growth and suppressed apoptosis. Moreover, the 3'-untranslated region (3'UTR) of Her-2, the epidermal growth factor receptor (EGFR) that transduces cell growth signals, appeared to be targeted by miR-133. Together, these data suggest that reduced miR-133 levels in GC tissues promote GC growth, which possibly contributes to a low survival rate of GC patients. MiR-133 may target Her-2 to suppress GC cell growth.