Long Non-coding RNA MEG3 Inhibit Colon Cancer Cells Proliferation And Migration Through Target To MiR-144

Objective:1.This study was aimed to investigate the expression level of MEG3 in colon cancer and to explore its clinical significance in colon cancer patients;2.This study aimed to indicated the interaction between MEG3 and miR-144 and revealed the function and mechanism of its downstream pathways in the process of colon cancer;we aimed to provide a new target marker for the diagnosis and treatment of colon cancer.Methods:1.Colorectal cancer tissues and adjacent normal tissues were collected from 80 colon cancer patients.2.The expression level of MEG3 and miR-144 was detected by real-time fluorescent quantitative PCR(RT-PCR)in different colon cancer cell lines(HT29,SW0480,SW620 and RKO cell lines)and expression level of MEG3 was detected by RT-PCR in cancer tissues and adjacent normal tissues.Then SPSS22.0 software was used to analysis clinical data.3.MEG3-siRNA and miR-144-inhibitor virus vectors were constructed by lentivirus technology.The above vectors were transfected into colon cancer cell line SW620 by lip2000 to obtain MEG3 and mi R-144 stable low expression colon cancer cell lines.4.Double luciferase reporter gene was used to analysis the interaction between MEG3 and miR-144.5.MTT proliferation assay and Transwell invasion assay were used to detect the changes of proliferation and invasion ability of colon cells after the expression of MEG3 was inhibited,and the inhibitory effect of colon cancer cell proliferation and invasion was recovered after the inhibition of mi R-144 expression.6.Western blotting was used to detect the expression of PTEN / AKT signaling pathway protein after inhibition of MEG3.Results:1.Compared with other colon cancer cell lines,the expression of MEG3 [(0.52±0.08),t = 9.968,P <0.001] was the lowest and the expression level of miR-144 was the highest in SW620 cells [(1.25±0.11),t = 9.648,P <0.05].The expression of MEG3 related to the pathological stage of colon cancer and the lymphnode metastasis.The higher the staging,the lower the expression of MEG3 in colon cancer.2.Double luciferase assay confirmed that MEG3 can specifically targeted to the 3’UTR of miR-144 and regulated the expression and activity of miR-144.3.Inhibition of MEG3 expression can promote cancer cell proliferation [(3.52±0.59),t = 3.289,P <0.05] and invasion [(321.52±23.24),t = 15.900,P <0.001].While after the inhibition of miR-144 expression level,the proliferation(3.63±0.48,t = 4.303,P = <0.05)] and invasion ability [(89.52±8.19)t = 15.327,P <0.001] of colon cancer cell were recovered.4.After the expression of MEG3 was inhibited,western blotting showed that the protein expression level of PTEN [(1.19 ± 0.15)%,t = 10.954,P <0.001] and AKT [(1.29 ± 0.18)%,t = 8.881,P < 0.001] were significantly increased.Conclusion:1.MEG3 was abnormally low expression in colon cancer patients,and it was related to the development and clinical stage of colon cancer.With the occurrence and development of colon cancer,the expression level of MEG3 was correspondingly decreased,which indicated that MEG3 may act as a tumor suppressor gene in colon cancer.2.MEG3 can activate the PTEN / AKT signaling pathway by regulating the expression of miR-144,thereby affecting the proliferation and invasion ability of colon cancer cells,which will provide a new target marker for the diagnosis and treatment of colon cancer.