Mechanistic Research On The Roles Of Lipid Metabolism-Related Genes In Endometrial Cancer

Objectives: Endometrial carcinoma(EC)is one of the most common malignancies in the female reproductive system and ranks seventh in the common malignancy.Metabolic diseases such as obesity,hypertension,diabetes is recognized as the three risk factors for endometrial cancer,while more and more studies have shown that tumor cell metabolism is closely related to the development of endometrial carcinoma.As one of indispensable factors of tumor growth,lipid metabolism has also attracted more and more attention fromresearchers.This study aim to investigate the molecular mechanism of the development of endometrial carcinoma from the perspective of abnormal lipid metabolism and to explore whether inhibiting the pathway of tumor cell metabolism could be an important method for the treatment of endometrial carcinoma.Contents: To investigate the status of lipid metabolism-related genes in endometrial carcinoma;to study the molecular mechanisms of lipid metabolism-related genes that are abnormally expressed in the EC;to explore the effect of three major factors related to obesity(Leptin / Insulin / Estrogen)on lipid metabolism-related genes in endometrial carcinoma.Methods:(1)Using the gene expression profile of endometrial carcinoma tissue samples to analyze the abnormal expression of lipid metabolism related genes(190 genes in KEGG pathway);GO,Cytoscape,Mev and so on were used to analyze the data;(2)Immunohistochemical technique was used to detect and analyze the protein level in EC tissue microarray(TMA).(3)The expression of ATP citrate lyase(ACLY)was knock down by lentivirus transfection,and then the effect of ACLY expression on the growth of EC cells was detected by CCK-8(Cell Counting Kit-8)/ clone formation / apoptosis and subcutaneous tumorigenesis.(4)The effect of ACLY on histone acetylation was analyzed by histone extraction and histone acetylation detection.The effect of ACLY on the growth of EC cells by histone acetylation was detected by CCK-8 and apoptosis assay.The target genes controlled by ACLY through histone acetylation were analyzed by the whole gene expression profile,and then verified the target gene by q PCR.(5)The effects of various factors on the lipid metabolism related-genes in EC cells were analyzed by using obesity-related factors such as insulin,leptin and estrogen.The effect of Signal transducers and activators of transcription 3(STAT3)on the promoter of ACLY and 3?-Hydroxysteroid-?24 reductase(DHCR24)was studied by Ch IP and Luciferase reporter gene.(6)The EC cells with DHCR24 RNA interference were treated with medroxyprogesterone acetate to study the sensitivity of EC cells to MPA.Results:(1)Through the analysis the whole gene expression profiling of endometrial carcinoma,fatty acid metabolism,steroid metabolism and sphingomyelin metabolism pathway were found abnomal in EC,particularly lipid metabolism related genes such as ACLY,DHCR24,CHKA,ACACA,FADS2.(2)The expression of ACLY in endometrial carcinoma was significantly higher than that in normal group,and the high expression of ACLY was closely related to the clinicopathological parameters such as clinical stage,histological grade and vascular infiltration.After ACLY knocking down,the proliferation ability of EC cells were decreased,the ability of cloning was decreased and the apoptotic rate increased.The ability of subcutaneous tumor formation of EC cells were decreased after ACLY interference.(3)ACLY could promote the acetylation of histone in endometrial cancer,and ACLY can promote the proliferation of EC cells and inhibit cell apoptosis by enhancing the acetylation of histones.It was found that ACLY activated the transcription of downstream cancer-promoting target genes and inhibited apoptosis-related signaling pathways by increasing the level of histone acetylation.(4)Insulin,E2 and Leptin can stimulate the expression of ACLY by STAT3.STAT3 can directly bind to ACLY promoter region to promote the expression of ACLY.(5)The prognosis of patients with high expression of DHCR24 in endometrial carcinoma was worse and the expression of DHCR24 were negatively correlated with the expression of progesterone receptor.Insulin could upregulate the expression of DHCR24 by STAT3.STAT3 could directly binds to the promoter region of DHCR24 and then promote its transcription.High expression of DHCR24 could regulate the migration of EC cells and the response to progesterone therapy.Conclusions: Lipid metabolism pathway changes significantly in endometrial cancer,lipid metabolism-related gene ACLY can promote the downstream cancer target gene transcription and inhibit the apoptosis-related signaling pathway by increase the acetylation of histone,and then promote the proliferation of endometrial cancer cells and inhibit the cell apoptosis.Lipid Metabolism Related Gene DHCR24 could regulate the migration of endometrial cancer cells and the response to progesterone therapy.