Expression Of Long Non-coding RNA MALAT1 In Hepatocellular Carcinoma Tissue And Its Actions On Proliferation And Invasion/ Metastasis Of Hepatocellular Carcinoma Cells

Objective:China is the country with the highest incidence of liver cancer in the world,and the disease mortality rate ranks third among cancers^[1].Surgery is still the main treatment for long-term survival of patients at this stage,but postoperative recurrence and metastasis is high.In addition,about 80%of patients have been in advanced stage or have distant metastasis at the time of initial diagnosis and lost their chance of surgery^[2-3].Therefore,to explore the mechanism of liver cancer metastasis,to find effective interventions has become the key to improve the status of liver cancer treatment.Long non-coding RNA?LncRNA?is a non-coding RNA of>200 nucleotides in length that regulates transcriptional,post-transcriptional,and post-translational levels of gene expression in a variety of physiology,epigenetic regulation,genomic imprinting and X chromosome inactivation,etc.)and pathology?including cancer,neurodegenerative diseases,immune dysfunction,cardiovascular and metabolic diseases,etc.?play an important role^[4].Metastasis-associated lung adenocarcinoma transcript 1?MALAT1?belongs to the lncRNA family and was first discovered in non-small cell lung cancer research^[5].There is increasing evidence that MALAT1 plays an important regulatory role in a variety of tumors.There is evidence that MALAT1 is highly expressed in a variety of tumors and is expected to be a diagnostic indicator for tumors^[6-7].Then,the expression of MALTA1 in liver cancer and its role in liver cancer are worthy of further study.This study was to detect the expression of MALAT1 in hepatocellular carcinoma by qRT-PCR,and analyze its relationship with various parameters of clinical data.At the same time,the role of MALAT1 in hepatocarcinoma cells was explored by CCK-8proliferation kit,Transwell assay and Western blot.Methods:In the experiment,85 cases of hepatocarcinoma and its matched paracancerous tissues were selected first.We used qRT-PCR to detect the expression of MALAT1 in 85cases of hepatocarcinoma and its paracancerous tissues.The relationship between the expression of MALAT1 and the clinicopathological factors of liver cancer patients was statistically analyzed.The liver SMMC-7721 cells were selected.We transfected SMMC-7721 cells with overexpressing MALAT1 and interfering MALAT1 plasmids,overexpressing and knocking out the gene MALAT1,and then detecting the proliferation of hepatocarcinoma cells by CCK-8 assay and Transwell experiment.The ability of hepatoma cells to proliferate,invade and metastasize was examined.Western blot was used to explore the effect of MALAT1 on the expression of EMT related marked protein E-cadherin and Vimentin?Results:The expression of MALAT1 in 85 cases of hepatocarcinoma and its adjacent paracancerous tissues was detected by qRT-PCR.The results showed that the expression of MALAT1 in hepatocarcinoma tissues was significantly higher than that in adjacent normal tissues?P<0.01?.Further statistics of MALAT1 in liver cancer tissues The relationship between the expression level and the clinicopathological parameters of liver cancer patients showed that the expression level of MALAT1 in liver cancer tissues was significantly correlated with tumor size,liver cancer differentiation,TNM stage and lymph node metastasis?P<0.05?.The expression level of MALAT1 in liver cancer tissues was not related to the clinical data of patients with liver cancer and the gender of patients?all P>0.05?.The overexpression of MALAT1 plasmid transfected liver cancer SMMC-7721 cells overexpressed MALAT1,and the proliferation,invasion and metastasis ability were significantly enhanced;the EMT related marked protein E-cadherin expression level was inhibited and Vimentin expression level was enhanced.While the transfection interference MALAT1 plasmid knocked down MAALT1significantly decreased proliferation,invasion and metastasis ability;the EMT related marked protein E-cadherin expression level was enhanced and Vimentin expression level was inhibited.?P<0.05?.Conclusion:The expression of MALAT1 was up-regulated in HCC tissues,and the expression of MALAT1 in HCC tissues was significantly correlated with tumor size,differentiation of HCC,TNM stage,and lymph node metastasis.MALAT1 can promote the proliferation,invasion,metastasis and EMT of hepatocellular carcinoma cells,which may be closely related to the occurrence and development of liver cancer,and provide potential targets for the clinical treatment of liver cancer.