MicroRNA-34a suppresses the invasion and migration of colorectal cancer cells by enhancing EGR1 and inhibiting vimentin.

MicroRNAs (miRNAs/miRs) are small non-coding RNAs that serve a post-transcriptional regulatory role in eukaryotes. Previous studies have demonstrated that the expression of miR-34a in colorectal cancer (CRC) tissues is decreased compared with that in normal colorectal tissues. However, the role of miR-34a in the invasion and metastasis of CRC remains unclear. In the present study, the levels of miR-34a expression were measured in various CRC cell lines. The cells were transfected with miR-34a mimics or inhibitors in order to assess the proliferation rate, and the colony forming, invasive and migratory abilities. Furthermore, the protein expression levels of vimentin and early growth response protein 1 (EGR1) were examined by western blot analysis. The results revealed that the expression of miR-34a was low in SW620, RKO, LoVo and Caco-2 cell lines and high in the SW480 and SW1116 cell lines. The migration, invasion and proliferation levels of SW480 cells were facilitated by decreasing the expression of miR-34a. Transient transfection with miR-34a mimics in SW620 cells caused a notable decrease in cell migration, invasion and proliferation levels compared with the control group, and a downregulation of vimentin and upregulation of EGR1 protein expression. The present study demonstrated that miR-34a was deregulated in a highly invasive CRC cell lines, and that it may attenuate the migratory, invasive and proliferative capabilities of CRC cells by enhancing the expression of EGR1 and inhibiting that of vimentin. The results of the present study represent important progress towards understanding the mechanisms of CRC recurrence and metastasis.

Schisandrin B protects PC12 cells against oxidative stress of neurodegenerative diseases.

Increasing evidence places Schisandrin B (Sch B) at an important position in nerve protection, indicating that Sch B might play a positive role in the therapy of neurodegenerative diseases. However, there is little information on it. Our studies showed that pretreatment with Sch B could reduce lactate dehydrogenase, malondialdehyde, and reactive oxygen species release and significantly increase the cell viability and the superoxide dismutase level. Sch B (10 µM) markedly inhibited cell apoptosis, whereas LY294002 (20 µM), a phosphatidylinositol-3 kinase inhibitor, blocked the antiapoptotic effect. More importantly, Sch B (10 µM) increased the phosphoprotein kinase B/protein kinase B (Akt) and B-cell lymphoma-2/Bcl-2 associated X protein ratios on preincubation with cells for 2 h, which was then inhibited by LY294002 (20 µM). Results indicate that Sch B can protect PC12 cells from apoptosis by activating the phosphatidylinositol-3 kinase/Akt signaling pathway and may emerge as a potential drug for neurodegenerative diseases.

[Effect of Schisandra chinensis lignans on neuronal apoptosis and p-AKT expression of rats in cerebral ischemia injury model].

OBJECTIVE: To observe the effect of Schisandra chinensis lignans (SCL) on neuronal apoptosis and PI3K/AKT signaling pathway of rats in the cerebral ischemia injury model, and study its possible mechanism. METHOD: Rats were orally administered SCL high, middle and low dose groups (100, 50, 25 mg x kg(-1)) for 14 days. The cerebral ischemia injury model was established by using the suture-occluded method to rate the neurological functions. The cerebral infarction area was observed by TTC staining. The pathological changes in brain tissues were determined by HE staining. Bcl-2 and Bax expressions were detected by immunohistochemical assay. The protein expressions of p-AKT and AKT were assayed by Western blotting. RESULT: Compared with the model group, SCL high, middle and low dose groups showed reduction in the cerebral infarction area to varying degrees, improve the pathological changes in brain tissues, promote the expression of apoptin Bcl-2 and p-AKT, and inhibit the expression of apoptin Bax. CONCLUSION: SCL shows a protective effect on rats with cerebral ischemia injury. Its mechanism may be related to the increase in p-AKT ability and antiischemic brain injury capacity and the inhibition of nerve cells.