Expression Of CD49 And CD73 In Renal Cell Carcinoma

Object:In recent years, research studies show that cancer stem cells may be a source of proliferation of malignant tumor and chemotherapy and radiation the main reason for tumor recurrence after treatment, therefore, the identification of cancer stem cells and biological characteristics are hot topics of current studies on malignant tumors. Clarification of surface molecular markers of the cancer stem cells may help targeted cancer treatment. Although cancer stem cells have been successfully isolated and identified from acute myeloid leukemia, multiple myeloma, breast cancer, pancreatic cancer, liver cancer, brain tumors, non-small cell lung cancer, melanoma, prostate cancer and bladder cancer and other types of tumor tissues, stem cells in renal cell carcinoma remain unrevealed yet. Our preliminary data show that there is Rhohigh subset in renal cell carcinoma, which possess cancer-stem characters. In this study, we focus on the initial identification of renal cell carcinoma surface markers.Method:Fresh tissues were taken from the collection of clinical patients with renal cell carcinoma and stained with rhodamine (Rh123) before submitted to flow cytometry assay. Two types of cells (Rhohigh and Rholow subsets) were sorted and their protein expression profiles were obtained with SILAC analysis in order to decide the candidates of the surface biomarkers of stem cells. By using antibodies labeled with a fluorescent agent, cells with specific markers were analyzed in detail.Results:Two distinct subpopulations (Rhohigh and Rholow) were observed in 24 clinic tissues with renal clear cell carcinoma stained by Rho 123 and the percentage of Rhohigh cells was 29.17±3.08%. A purity of 92.43% for Rholow cells and76.2% for Rhohigh cells were achieved by FACScan cell sorting. Basing on reference investigation and SILAC protein expression profiles, the biomarker candidates were picked. Expression of CD73, CD81, CD82, CD49c (integrin alpha 3), CD315 (CD9P-1, EWI-F, FPRP), CD249 (Gp160), CD26, and CD36L1,on the two subpopulations were further examined. Results show that there are significant differences of CD73 and CD49c between Rhohigh and Rholow cells. Relative enrichment of CD73 and CD49c cells by radiation and chemotherapy regeants. Theses results imply that CD73 and CD49c might be potential surface biomarkers of renal clear cell carcinoma stem cells, even though further confirmation has to be performed.