Expression Of ACE2,PRR And AT2R In Renal Carcinoma Stem Cells

ObjectivesThe objective of this study was to investigate the expression of renin-angiotensin system(RAS)components on tumor stem cells(CSCs)in renal clear cell carcinoma(RCCC).It provides a theoretical basis for RAS inhibitors to treat RCCC and improve the overall survival of patients.MethodsRCCC tissue samples with both paraffin and fresh frozen specimens were selected from the pathology bank.The RAS components of the samples: Renin(Renin),Renin proto-receptor(PRR),angiotensin converting enzyme(ACE),angiotensin converting enzyme 2(ACE2)and angiotensin II receptor 2(AT2R)were immunohistochemically stained.OCT4 or KLF4 were used as CSCs markers and RAS components respectively for immunofluorescence co-staining or immunohistochemical double staining.Westernblot and reverse transcription quantitative polymerase chain reaction(RT-q PCR)were used to quantitatively study the protein and gene expression of these RAS components in RCCC tissue samples.In addition,the expression of angiotensin II receptor 1(AT1R)was analyzed by RT-q PCR.ResultsImmunohistochemical staining showed that the expression rates of renin,PRR and ACE2 in all RCCC samples were 88.57%,94.29% and 94.28%,respectively.All RCCC samples expressed AT2 R.However,ACE is only expressed in endothelial cells of blood vessels in normal tissues.Dual immunohistochemical staining showed that ACE2 and KLF4 were co-expressed on CSCs,but renin was not found on CSCs.Immunofluorescence double-label staining showed that PRR and AT2 R were localized on OCT4-positive CSCs, respectively.The results of Western Blotting showed that PRR,ACE,ACE2 and AT2 R proteins were expressed in RCCC tissue samples.All samples expressed PRR protein.The expression rates of ACE,ACE2 and AT2 R were 91.42%,88.57% and 85.71% respectively.The expression of renin was also not observed.RT-q PCR was used to detect the expression levels of PRR,ACE,ACE2 and AT1 R.It was found that all RAS components including AT1 R were transcribed in all RCCC tissue samples,and renin expression was detected in 85.71% of the samples.However,AT2 R was not expressed.ConclusionsThis study confirmed the expression of PRR,ACE2 and AT2 R on CSCs in RCCC.The regulation of RAS components by targeting CSCs may be a new therapeutic approach for RCCC aggressive cancers.