| Cholangiocarcinoma(CCA),which originates from bile duct epithelium cells,is a common malignant tumor of biliary tract with hidden onset,high malignant degree,late diagnosis and poor prognosis.The retinoic acid receptor y(RARy)of the nuclear receptor family is involved in the proliferation,migration and invasion,drug resistance and other malignant phenotypes of many malignant tumors by regulating multiple signal transduction pathways.However,the molecular mechanism of RARy regulating tumorigenesis and development is not clear,and the mechanism of its abnormal high expression has not been clarified.In this study,proteomics combined with bio informatics analysis was used to explore the molecular mechanism of RARy regulating the occurrence and development of CCA,and to study the regulation mechanism of its high expression from the point of view of tumor microenvironment.The purpose of this study is to provide scientific experimental basis for it's role as a therapeutic target for CCA.In this study,the systematic analysis of proteomics combined with bioinformatics analysis showed that the knockdown of RARy in CCA cells mediated the changes of many substance metabolism,especially the expression of enzymes related to glucose metabolism.Further studies showed that the knockdown of RARy significantly:inhibited glucose uptake,lactate secretion and intracellular ATP production in CCA cells.In addition,the detection of extracellular metabolic flow showed that knockdown of RARy could significantly reduce the extracellular acidification rate and increase the oxygen consumption rate,which further confirmed that knockdown of RARy could promote the transformation of aerobic glycolysis phenotype to aerobic oxidation of CCA cells.In order to further study the mechanism of RARy regulating glycometabolism reprogramming in CCA cells,we screened and identified AKR1C1,a member of the aldosterone reductase family 1,a target protein regulated by RARy selected from proteomic differential proteins.Inhibition of AKR1C1 activity could inhibit aerobic glycolysis and proliferation of CCA cells.Irmmunohistochemical examination showed that AKR1C1 was significantly overexpressed in CCA,and its high expression was closely related to the tumor size and poor differentiation of pathological grade of CCA,and positively correlated with the high expression of RARy.AKR1C1 can be used as a predictor of poor prognosis of CCA.Our previous studies have found that RARy could act asa an oncogene to regulate the occurrence and development of CCA,but the regulatory mechanism of abnormally high expression of RAR y in CCA is not clear.Our research investigated the effect of microenvironment of CCA cells on RARy expression from the perspectives of tumor inflammation,nutritional deficiencies and hypoxic microenvironment.The results showed that inflammatory factors,sugar-free culture and hypoxia microenvironment could induce the increase of RARy expression in CCA cells,and the abnormal activation the pathways which closely related to the three microenvironments like NF-?B,STAT3,AMPK and HIFla signaling pathways regulated the abnormal expression of RAR y in CCA cells.To sum up,RAR y is involved in the reprogramming of glucose metabolism in CCA cells by regulating the expression of a variety of glucose metabolic enzymes.RARy can regulate the aerobic glycolysis of CCA cells through the downstream target AKR1C1.AKR1C1 may be involved in the occurrence and development of CCA as an oncogene.The abnormal expression of RARy in CCA is closely related to three tumor microenvironments:inflammatory microenvironment,nutritional deficiency microenvironment and hypoxia microenvironment.This study preliminarily clarified the mechanism of RAR y regulating the reprogramming of glucose metabolism and its abnormal high expression in CCA,and provided a scientific experimental basis for RAR'y as a therapeutic target for CCA. |
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