MiR-149 Regulates Proliferation And Apoptosis Of Gastric Cancer Cell

Gastric cancer is a common malignant disease in the world and is aslo the second major cause of cancer death in the worldwide.Although the diagnostic procedures and treatment strategies for gastric cancer have improved,patients with gastric cancer still have the risk of metastasis,recurrence,and poor prognosis.Therefore,it is particularly important to study the molecular mechanism of gastric cancer.MiRNAs are highly conserved,non-coding RNA molecules of about 20 nucleotides in length.And miRNAs can degrade the target gene mRNA and inhibit translation by specifically binding the 3'-UTR of the target gene mRNA.MiR-149,as an oncogene or tumor suppressor gene,plays an important role in the development of various tumors,but the mechanism of miR-149 in gastric cancer remains unclear.This research mainly focused on the mechanism of miR-149 in gastric cancer cell and miR-149 regulates proliferation and apoptosis of gastric cancer cell.After overexpression of miR-149 in gastric cancer cell line SGC7901,mRNA was extracted from cells,reverse transcription,and detection of downstream gene expression of the Akt signaling pathway by Real-time PCR.We found that miR-149 can effectively inhibit the expression of PHLPP2,Bim,Foxo1,Bid,p21 and other genes,and has a significant effect on some genes of the Bcl-2 family.We found that 50 nM miR-149 can promote the proliferation of gastric cancer cells through MTT assay and cell proliferation experiments,and the effects of different concentrations of miR-149 on the cells are different.Through the cell scratch test and cell migration experiments,we found that the effect of miR-149 on cell migration was changed from promotion to inhibition with increasing transfection concentration.Therefore,we speculated that the specific concentration of 50 nM miR-149 in gastric cancer cell line SGC7901,as a tumor promoting factor,will affect the development and progression of gastric cancer.As a tumor suppressor gene,PHLPP2 participates in the development of tumor,and PHLPP2 negatively regulates Akt signaling pathway by dephosphorylation of Ser 473 sites of Akt.PHLPP2 plays a important role in the proliferation,apoptosis and migration and invasion of the tumor cells.In this study,the target relationship between miR-149 and PHLPP2 has been first demonstrated by dual luciferase reporter assay.Overexpression of miR-149 in gastric cancer cells and total protein extracted from cells were performed in Western-Blot test.The experimental results proved that miRNA-149 can promote the activation of Akt phosphorylation.Furthermore,after inhibiting Akt phosphorylation with LY294002(PI3K/Akt inhibitor),transfection of miR-149,which also had the similar effect of promoting the activation of Akt phosphorylation,compare with NC group.To sum up,our research shows that:miR-149 can inhibit PHLPP2 promote Akt signaling pathway to regulate gastric cancer cell proliferation and apoptosis balance in gastric cancer.In the future,miR-149 may become a new target for gastric cancer prevention.These findings have enriched the molecular mechanism of the occurrence and development of gastric cancer and expanded the targeted treatment of gastric cancer.