Study On The Different Biological Characteristics Of CD133~+ Cells And CD133~- Cells In Renal Cell Carcinoma

Background CD133 was used as a marker to detect stem cells (progenitor cells)and cancer stem cells(tumor-initiating cells)in various tissues.The purpose of this study was to investigate the different biological characteristics of CD133⁺ cells and CD133^-cells in renal cell carcinoma with in vitro analyses.methods The CD133 surface expression of both 786-0 and OS-RC-2 cell lines was evaluated by flow cytometry.CD133⁺ cells were isolated by MACS(magnetic activated cell sorting)and examimed in vitro proliferation,growth characteristics and colony formation efficiency(CFE). Flow cytometry was used to evaluate the cell cycle distribution and long-term differentiation ability.The sensitivity to diamminedichloroplatinum(DDP)between CD133⁺ cells and CD133^-cells were contrasted by drug sensitivity testing in vitro(MTT assay).Result CD133 surface expression were found in 2 /2 RCC cell lines.It was shown that isolated CD133⁺ cells from 786-0 and OS-RC-2 cell lines are more proliferetive and have higher colony-forming and more long-term differentiation abilities than CD133^-cells in vitro.CD133⁺ cells from 786-0 and OS-RC-2 cell lines had relatively shorter colony doubling time than CD133^-cells[(19.46 h vs 22.03 h)and(18.80 h vs 22.26 h)] indicating that the growth of CD133⁺ cells was faster.There was significant difference in the mean CFE between CD133⁺ cells and CD133^-cells of 786-0 and OS-RC-2 cell lines[(38.47±4.27)%vs(21.38±3.58)%and (32.47±5.21)%vs(26.04±7.12)%,P＜0.01].There also was significant difference in the cell cycle distribution between CD133⁺ cells and CD133^-cells[(65.77±0.81)%vs(44.9±2.21)%and(61.58±1.32)%vs (42.93±3.11)%]in G₀/G₁ phase,(13.65±0.42)%vs(39.66±1.25) %and(12.17±0.22)%vs(37.80±0.32)in S phase,and(10.83±0. 35)%vs(12.24±0.31)%and(11.36±0.22)%vs(16.23±0.36)% in G₂/M phase,P＜0.01].Additionally,the difference of sensitivity to diamminedichloroplatinum(DDP)between CD133⁺ cells and CD133^-cells was not significant.Conclusion It was confirmed that CD133⁺ cells in RCC cell lines are useful markers for the detection of cancer stem cells(tumor-initiating cells).The subsequent further biological characterization of CD133⁺ cells in RCC cell lines shoul reveal whether they possess features of stem cells such as the capacity for increased tumorgenity.The biological characteristics of CD133⁺ cells in RCC cell lines will help elucidate more details of cancer stem cells in RCC.