Antitumor Effects Of Sphingosine Kinase 1 Inhibitor Combined With Chemotherapeutic Drugs On Proliferation And Apoptosis Of Gastric Cancer Cells In Vitro

Objective: To investigate the effects of SPHK1 inhibitors DMS combined with chemotherapeutic drugs 5-FU,OXA,MMC on the proliferation and apoptosis of gastric cancer cells(SGC7901) in vitro, and to evaluate whether SPHK1 inhibitors can be used as synergetic agents in chemotherapy.Methods:The gastric cancer cell line SGC7901 cells were incubated in vitro with 5-FU,OXA,MMC and DMS (concentration gradient of 5-FU,OXA:0.5μg/ml,2.5μg/ml, 12.5μg/ml; concentration gradient of MMC:0.05μg/ml,0.25μg/ml,1.25μg/ml; DMS: 1.0μmol/l) in combination or respectively for 24h. The effects of the treatments on the growth and survival of SGC7901 were determined by MTT assay for 24h. Apoptosis was measured using flow cytometry and Expression of SPHK 1 mRNA was determined by RT-PCR. The data was analyzed by SPSS and SAS software.Results: 1.The inhibition rate of gastric cancer cells by treatment with DMS 1.0μmol/l for 24h was 10.23%±0.74%.The inhibition rates of gastric cancer cells by treatment with 5-FU for 24h at different concentrations (concentration gradient of 5-FU: 0.5μg/ml,2.5μg/ml,12.5μg/ml) were respectively 9.38%±0.79%,19.61%±0.90%,29.83%±0.54%;The inhibition rates with OXA(0.5μg/ml,2.5μg/ml,12.5μg/ml) were 9.95%±3.24%, 21.04%±2.19%,45.49%±3.60%;The inhibition rates with MMC(0.05μg/ml,0.25μg/l, 1.25μg/ml) were 15.35%±0.77%,24.72%±0.83%,30.68%±0.28%.when chemotherapeutic drugs(5-FU,OXA,MMC) were combined with DMS at different concentrations, the inhibition rates were 15.35%±0.86%,25.57%±0.27%,36.37%±0.54%;16.76%±0.41%, 27.28%±0.29%,52.56 %±0.36 % ;21.02%±0.28%,32.10%±0.27%,36.36%±0.28%,which showed a synergetic effect(P<0.05). 2.The apoptosis rates of SGC7901 cells were 7.56%±1.47%,9.08±2.04% when treated with DMS1.0μmol/l and 5-FU 0.5μg/ml respectively,more than 10.23%±0.74% in control group;and when 5-FU was combined with DMS, the apoptosis rate was 17.68±3.66%, more than each of the single drug group(P<0.05).3. RT-PCR revealed that 5-FU respectively or combined with DMS could decrease the expression of SPHK 1 mRNA markedly; but in single DMS group, DMS 1.0μmol/l did not inhibit the expression of SPHK 1 mRNA obviously.Conclusion: 1.DMS had an ability to suppress gastric cancer cells in vitro,and the synergetic effect became evident when it was combined with chemotherapeutic drugs. 2. DMS could induce the apoptosis of SGC7901 cells respectively or in combination with chemotherapeutic drug 5-FU.3.5-FU or combined with DMS could decrease the expression of SPHK 1 mRNA obviously.