Analysis of the characteristics of side population cells in the human ovarian cancer cell line OVCAR-3 / 中华妇产科杂志

ABSTRACT

ObjectiveTo identify the presence of side population (SP) cells in human ovarian cancer cell line OVCAR-3 and to investigate whether SP cells have the characteristics of cancer stem cells.MethodsSP and non-SP (NSP) cells from OVCAR-3 were isolated by fluorescence-activated cell sorting after being stained by DNA-binding dye Hoechst 33342.Limiting dilution transplantation assay,realtime PCR,and drug sensitivity assay were performed to compare the tumorigenic ability,differentiation ability in vivo,the mRNA expressiou of stemness marker (Oct-4,Klf4,and Nanog) and ATP-binding cassette (ABC) transporter (ABCG2,ABCB1,and ABCC2),and response to multiple drugs (cisplatin,paclitaxel,doxorubicin,and mitoxantrone )between SP and NSP cells.ResultsA few of SP cells [ ( 1.13 ±0.39) ％ ] which were sensitive to reserpine were identified in OVCAR-3 cells.The injection of as few as 102 SP cells initiated tumors in two of five mice.Tumor latency was 52 -61 days.However,the NSP cells did not generate any tumors in mice until 104 NSP cells were injected (two of five mice).Tumor latency was 64 - 98 days.Tumorigenicity of SP cells was enhanced by at least 100-fold than that of NSP cells.The SP cells regenerated both SP [ ( 2.09 ± 0.73 ) ％ ] and NSP populations in vivo with a fraction size that was comparable to the original population.The mRNA expression ofstemness genes Oct-4,Klf4 and ABC transporters ABCG2,ABCC2 genes were elevated in SP cells compared to NSP cells,the fold changes were 1.95±0.41 (P＜0.05),4.26 ±0.63 (P＜0.01),3.22±0.36 (P＜0.01),and 1.76±0.26 (P＜0.01 ),respectively.The relative activity of SP and NSP cells were 0.757 ± 0.105 versus 0.474 ± 0.035 (P＜0.01),0.521 ±0.092 versus 0.384 ±0.073 (P＜0.05),0.742 ±0.051 versus 0.526 ±0.088 (P ＜0.01 ),and 0.690 ± 0.096 versus 0.466 ± 0.112 ( P ＜ 0.01 ) when they exposed to 0.25 μg/ml cisplatin, 0.01μmol/Lpaclitaxel, 0.25μmol/Ldoxorubicin, and0.05μg/mlmitoxantrone,respectively.ConclusionsSP cells from OVCAR-3 have enhanced self-renewal,differentiation,and tumorinitiating capacity compared to NSP cells.The mRNA expression of stemness genes and ABC transporters are markedly elevated in SP cells,which showed resistance to multiple chemotherapeutic drugs and have characteristics of cancer stem-like cells.Therefore,SP phenotype could be used as a marker to isolate the cancer stem-like cells in ovarian cancer.