LncRNA TUG1 Regulates Liver Cancer Growth And Tumor Immunity

Research background and purpose:As a star molecule in tumor regulation-related research,LncRNA TUG1 can regulate gene expression through various methods such as epigenetics and transcription,and then perform a variety of pathological and physiological functions.CD47 is a transmembrane protein that can be expressed on the surface of a variety of cancer cells as a signaling molecule to prevent phagocytosis by macrophages and mediate tumor immune escape.Mi R-340 is a non-coding RNA with regulatory functions that has evolved conservatively in various organisms,miR-340 can interact with various biomolecules and affect tumor progression.In this paper,by studying the expression of LncRNA TUG1,miR-340and CD47 in hepatocellular carcinoma and their influence on the development of hepatocellular carcinoma,the mechanism of LncRNA TUG1’s antitumor immune regulation in hepatocellular carcinoma is explored.Research method:Star Base and Linked Omics databases were used to analyze the expression of LncRNA TUG1 and the relationship between LncRNA TUG1 and CD47 in liver cancer.In vitro experiments,recombinantly constructed si-TUG1lentivirus stably transformed cells in mouse liver cancer cells,and co-cultured the above cells with vitro induced macrophages;Si-TUG1 mimic transiently transfected,and the effects of TUG1 on tumor-related functions were studied by CCK-8,scratch and apoptosis.In vitro mechanism study,explore the intermediate molecules that interact with LncRNA TUG1 and CD47 through the interaction relationship between sequences,and verify through luciferase experiment,q PCR and western blot experiment;Constructing overexpression miR-340 stable cells to detect its effect on vitro phagocytosis and tumor cell function.In vivo studies,hepatocarcinoma cells(si-TUG1,overexpression miR-340)were injected subcutaneously into C57BL/6mice,recorded tumor growth curves;Flow cytometric studied relevant immune cells in the spleens and tumor cells with si-TUG1 and overexpression miR-340.Taking tumor tissues for immunohistochemical staining to analyze the relationship of TUG1,miR-340 and CD47.Research result:Through bioinformatics analysis,we found that the expression of LncRNA TUG1 and CD47 in liver cancer were increased,the expression of LncRNA TUG1 and CD47 in liver cancer were positively correlated,and miR-340 played an important role between the two,reducing TUG1 in liver cancer,the level of miR-340increased and CD47 surface of tumor cells decreased.When reduced TUG1,the phagocytosis of tumor cells by vitro macrophages was increased,the growth and migration of tumor cells slowed down,and the proportion of cell apoptosis increased.In addition,When miR-340 overexpressed in Hepa1-6 cells,the expression of CD47on the cell surface decreased,the proportion of phagocytosis increased.Through vivo studies,we found that the growth of tumor cells was significantly inhibited,and the ratio of CD4~+T cells and CD8~+T cells in mouse spleen and tumors increased,the proportion of M1 macrophage polarization increased significantly in si-TUG1 and miR-340 overexpressed,and the results of intratumoral immunohistochemical analysis showed that the expression of CD47 on the tumor surface decreased significantly in si-TUG1 and miR-340 overexpressed.Research conclusion:LncRNA TUG1 in liver cancer cells can further increase the expression of CD47 on the cell surface by down-regulating miR-340,thereby regulating the growth of liver cancer cells and their immune microenvironment.It was found that when the level of LncRNA TUG1 decreased,the expression of miR-340 would increase,the expression of CD47 on the cell surface would be inhibited,the polarization of M1 type macrophages would be promoted to clear tumor cells.At the same time,LncRNA TUG1 interacts with miR-340 to activate CD4~+T cells and CD8~+T cells to promote anti-tumor immunity.Therefore,changes in the expression of TUG1 may be an important indicator of the prognosis of liver cancer,and itself may be an important molecule that regulates the growth of liver cancer and its immune microenvironment.Interfering with the expression of LncRNA TUG1 may become a new strategy for clinical immunotherapy of liver cancer.