The Relationship Between The Level Of DHCR24 And The Clinicopathological Significance And Its Effects On Biological Behavior In Breast Cancer

Objective:Metabolic abnormalities can promote the occurrence and development of breast cancer,screening out potential biomarker or therapeutic target for breast cancer in abnormal cholesterol metabolism by comparing the sequencing results with the databases,and further exploring its influence on the biological behavior and possible mechanism of breast cancer and EMT.Methods:Database comparison and bioinformatics analysis was performed to screen out the potential biomarker or therapeutic target gene in breast cancer,and immunohistochemical staining was used to verify its expression in breast cancer tissues and adjacent cancer tissue sections;Quantitative PCR and Western Blot were used to select the interference model cells of target gene,the lentiviral transfection was used to knockdown or overexpress target gene,the transfection efficiencies were verified by quantitative PCR and Western Blot,then CCK8 assay was used to test the ability of cell proliferation、the Flow Cytometry was applied to detect the changes of apoptosis and cell cycle、the Transwell chamber experiment was used to analyze the abilities of migration and invasion;Finally,the expression level of EMT-related proteins including E-cadherin,β-catenin,p-β-catenin and Vimentin were detected by Western Blot.Results:DHCR24,a cholesterol metabolism-related factor,which was found highly expressed in non-triple negative breast cancer through the research group sequencing results and database comparison,and then found it potential research value through bioinformatic analysis and screening;The immunohistochemical results showed that the high expression of DHCR24 was mainly concentrated in PR and HER-2 positive breast cancer tissues,while it was low expressed in triple negative breast cancer(TNBC)tissues.Compared with normal breast epithelial cells MCF-10A,the results of quantitative PCR and Western Blot showed that the DHCR24 was highly expressed in non-triple-negative breast cancer cell lines SK-BR-3,T-47d and MCF-7,basic agreement with the expression of the TNBC cell line BT549,largely not expressed in another TNBC cell line MDA-MB-231,then MCF-7 and MDA-MB-231 cells were selected as the model cells according to the preliminary experiment based on the model construction.The results of quantitative PCR and Western Blot showed that the DHCR24 overexpression in MDA-MB-231 cells was unsuccessful,knock-down and restore in MCF-7 cells was successful.Then,we found that the ability of proliferation,migration and invasion were enhanced,the proportion of apoptotic cell was decreased,the proportion of S-phase cell was increased after DHCR24 knockdown,and all biological behavior changes in cells had different degrees restored after DHCR24 restore;The Western Blot results of EMT-related proteins showed that the expression of the epithelimal-like markers E-cadherin,β-catenin,and p-β-catenin decreased first(DHCR24 knockdown)and increased later(DHCR24 restore),while the expression of the interstitial-like marker vimentin increased first and then decreased.Conclusion:DHCR24,the enzyme of cholesterol metabolism,is generally highly expressed in non-triple-negative breast cancer tissues and cells but the opposite in triple-negative breast cancer;DHCR24 mainly plays a similar role as a tumor suppressor in MCF-7 cells;The similar tumor suppressor effect of DHCR24 in MCF-7 cells may be triggered by the regulation of EMT.