The Mechanism Of LncRNA NEAT1 In Regulation Of Proliferation And EMT Upon Mechanical Stimuli In Liver Cancer

Extracellular matrix(ECM)-derived mechanical stimuli regulate many cellular processes and phenotypes through mechanotransduction signaling pathways.Substrate stiffness changes cell phenotypes and promotes angiogenesis,epithelial to mesenchymal transition(EMT),and metastasis in tumors.Enhanced liver tissue matrix stiffness plays a crucial role in the tumorigenesis and malignant development of liver cancer and is associated with unfavorable survival outcomes.However,how liver cancer cells sense changes in ECM stiffness and the underlying molecular mechanisms are largely unknown.How ECM stiffness impacts liver cancer cellular processes and malignant development needs further study.Thus,we aim to explore the effect of different mechanical cues on the expression of NEAT1 and the malignant development of cancer in the liver microenvironment.In this study,we demonstrate the conclusions:(1)To simulate the change of ECM stiffness,we fabricated a model of 3D topological micropillars.The hepatoblastoma-derived hepatocellular carcinoma HepG2 cells were seeded on 3D topological microcolumns.We found that higher substrate stiffness dramatically enhanced malignant cell phenotypes and promoted G1/S transition in HepG2 cells.Besides,we also found that higher matrix stiffness contributed to enhancing lncRNA NEAT1 expression,indicating that lncRNA NEAT1 was a matrix stiffness-responsive lncRNA.(2)Higher matrix stiffness inhibited the expression of E-Cadherin and upregulated the expressions of N-Cadherin,VIM,ZEB1,Snail1,and SLUG.Our further research has revealed that higher matrix stiffness inhibited the phosphorylation level of β-catenin and increased the nuclear translocation of β-catenin,which helped to activate the Wnt/β-catenin pathway and promote the downstream of the Wnt/β-catenin pathway.(3)Silencing of lncRNA NEAT1 promoted the expression of p-β-catenin and inhibited the activation of Wnt/β-catenin pathway.Blocking the expression of lncRNA NEAT1 upregulated the expression of E-cadherin and inhibited the expression of the transcription factor ZEB1,thereby inhibiting the EMT process of liver cancer.Therefore,these results indicate that matrix stiffness can regulate the expressions of metastasisrelated factors RUNX2 and CD44,angiogenesis-related factors HIF-1α and VEGFA,and proliferation-related molecules c-myc and cyclin D1,thereby promoting the malignant development and EMT process of HepG2 cells.(4)The RNA binding protein YB-1 was found to be interacted with lncRNA NEAT1.Silencing YB-1 affected the downstream expressions of AKT,ERK and E-cadherin.Further studies have indicated that the expression of YB-1 impacted the function of lncRNA NEAT1.(5)Animal experiments illustrated the effect of lncRNA NEAT1 on tumor growth.Silencing lncRNA NEAT1 weakened the growth of the tumor and diminished the weight and volume of the tumor.Inhibition of lncRNA NEAT1 reduced the activation of β-catenin pathway.Therefore,our findings provide evidence that ECM-derived mechanical signals regulate cell proliferation and drive EMT through a NEAT1/Wnt/β-catenin mechanotransduction pathway in the tumor microenvironment of liver cancer.This research possesses an important significance for the clinical treatment of liver cancer and provides certain theoretical support and feasible plans,indicating that lncRNA NEAT1 can be served as a potential therapeutic target.