The Effects Of Chemokine SDF-1 And Its Receptor CXCR4 On The Biological Behavior Of Ovarian Cancer Cells

ObjectiveOvarian cancer is malignant tumor which seriously imperil the health of women, the death rate of which hold primacy in gynecologic tumor. About 70 percent of patients have local or distant metastases before they seek medical attention. Advance of operation and chemotherapy in recent years can't improve the total survival rate of patients, so specialists in gynecologic oncology have to seek other methods for early diagnosis and therapy. Recent studies indicate that chemokines and their receptors are involved in the proliferation, differentiation, metastasis of tumor cells. Meanwhile, more and more specialists pay attention to the relationship between the chemokine SDF-1 and its receptor CXCR4. To study the effect of SDF-1/CXCR4 biological axis on the biological behavior of ovarian cancer cells, we detect the expression of CXCR4 in human ovarian cancer cell line SW626 and Anglne, investigate how SDF-1/CXCR4 biological axis work on the proliferation, apoptosis and metastasis of them, and try to find a new therapeutic strategy to cure ovarian cancer. Materials and Methods1. Cell linesHuman ovarian cancer cell line SW626 and Anglne were purchased from China Center for Type Culture Collection (CCTCC, Wuhan University).2. MaterialsDMEM and RPMI-1640 culture medium, RNA isolation TRIzol Reagent (Gibco, USA); New- born Calf Serum (Hyclone, USA); AMV reverse transcriptase, Taq polymerase (Takara, Japan); MTT (Thiazolyl Blue), DMSO (dimethylsulfoxide), PI (propidium iodide) (Sigma, USA); SDF-1α(PeproTech, USA); Anti-human CXCR4 Monoclonal Antibody (Ig2b44716clone, R&D systems, USA); Matrigel Basement Mem- brane Matrix (BD, USA); Transwell (24-well format, 8-μm pore) (Costar, USA).3. Methods①SW626 cells were cultured in DMEM medium containing 20% new-born Calf Serum, Anglne cells were cultured in RPMI-1640 medium containing 10% new-born Calf Serum. Cells were cultured in a humidified atmosphere with 5% CO2 at 37°C, and the medium was changed every 48 hours.②The expression of CXCR4 mRNA in SW626 and Anglne cells was detected by reverse transcriptase polymerase chain reaction (RT-PCR).③The proliferation effect of SW626 and Anglne cells treated with SDF-1αand anti- CXCR4 mAb was detected by MTT assay.④The effect on cell cycle and apoptosis of SW626 and Anglne cells treated with SDF-1αand anti- CXCR4 mAb was analyzed by Flow Cytometry.⑤Transwell was used to analyze the chemotaxis and invasion of ovarian cancer cells in presence of SDF-1α, and when CXCR4 neutral- lization was applied.4. Statistical AnalysisAll results were expressed as the mean±standard deviation (x±SD). Statistical analysis was performed using t test, and P<0.05 was considered statistically significant. Results1. CXCR4 mRNA is expressed in SW626 cells and it can't be detected in Anglne cells.2. Proliferation of SW626 cells didn't change significantly after 100ng/ml SDF-1αtreatment (Absorbance value, A=0.796), compared with those of control (A=0.774); 20μg/ml anti-CXCR4 mAb inhibited the proliferation of SW626 cells (A=0.520), significantly lower than those of control (P<0.05). There was no significant effect of SDF-1αand anti-CXCR4 mAb on Anglne cells (P> 0.05).3. 100 ng/ml SDF-1αdid not increase proliferation of SW626 cells and protect them from apoptosis (Proliferation Index, PI=(62.3±2.8)%; Apoptosis Index, AI=(14.5±0.9)%), compared with those of control (PI=(61.6±2.4)%; AI=(14.7±1.7)%); 20μg/ml anti-CXCR4 mAb inhi- bited the proliferation of SW626 cells (PI=(37.5±1.1)%), significantly lower than those of control (P<0.05). There was no significant effect of SDF-1αand anti-CXCR4 mAb on Anglne cells(P> 0.05).4. 100 ng/ml SDF-1αinduced chemotaxis and invasion of SW626 cells, the chemotactic index (CI) and invasion index (II) were 3.1±0.5 and 3.8±0.4, significantly higher than those of control (P<0.05); both chemotaxis and invasion could be blocked by anti-CXCR4 mAb, the inhibition rates (IR) were68.6±7.7%, and 73.1±3.3%, significantly higher than those of control (P<0.05). There was no significant effect of SDF-1 and anti-CXCR4 mAb on Anglne cells (P> 0.05).Conclutions1. CXCR4 mRNA is expressed in SW626 cells and it can't be detected in Anglne cells.2. Anti-CXCR4 mAb could inhibit the proliferation of CXCR4+ ovarian cancer cells.3. SDF-1 could induce chemotaxis and invasion of CXCR4+ ovarian cancer cells and anti-CXCR4 mAb could block the effect. 4. SDF-1 and CXCR4 may play an important role in the prolifer- ation and metastasis of ovarian cancer cells, and intervention with the interaction of SDF-1 and CXCR4 could be a meaningful therapeutic target and strategy.