The Effect Of P₅ With Cisplatin To Enhancing Drug Sensitivity And Reversing Drug-resistance Of Ovarian Carcinoma Cells In Vitro

Objective: Chemical therapy is the necessary way to treat ovary carcinoma, and the first choice of chemical drugs for treating ovary carcinoma is cisplatin(DDP). But nowadays, high rate of recurrence and resistance to DDP, even to multiple chemotherapy drugs, induce a poor prognosis of ovary carcinoma cases. P₅ is a kind of apoptosis inducing nucleosides (AINs) and has apoptosis inducing effect on many kinds of tumor cells, but doesn't have toxicity in normal cell. These studies is to observe whether Ps could enhance DDP's chemical sensitivity on ovary carcinoma cell line COC1 which is sensitive to DDP, and whether it could reverse the drug-resistance on ovary carcinoma cell line COC1/DDP which is resistant to DDP in some how, and if these effects have any relations with it's dosages, and to give the experimental basis for reversing the DDP-resistance on ovarian carcinoma, and to give a new strategy to improving the ovarian carcinoma sufferers' prognosis. P₅ and DDP were used only as comparison in vitro.Method:Part 1: By Taifan blue dye, MTT, Hoechst staining and flow cytometer, observe P₅'s inhibitory effects and chemical sensitivity-enhancing effects on ovary carcinoma cell line COC1 which is sensitive to DDP;Part 2: By Taifan blue dye, MTT, Hoechst staining and flow cytometer, observe P₅'s DDP-resistance reversing effects on ovary carcinoma cell line COC1/DDP which is resistant to DDP.Results:Part 11. DDP' s IC₅₀ is 2.5μg/ml on COC1, P₅ has not the inhibitory effect;2. Small dosage of P₅ (25μg/ml) and large dosage of P₅ (200μg/ml) descend the IC₅₀ of DDP from 2.51μg/ml to 1.57μ/ml～1.51μg/ml on COC1;3. By Hoechst staining, small dosage of P₅ (25μg/ml) and large dosage of P₅ (200μg/ml) act with DDP, the cell apoptosis ascend clearly on COC1;4. ByFCM, small dosage of P₅ act with DDP, small dosage of P₅ act with DDP ascended the apoptosis rate and the proportion of S, G₂/M stages, descended the proportion of G₁ stage on COC1 compared with used single P₅ or DDP; large dosage of P₅ act with DDP make plenty of the COC1 cells dead and broken up.Part 21. DDP' s IC₅₀ is 4.96μg/ml on COC1/DDP, P₅ has not the inhibitory effect;2. Small dosage of P₅ (25μg/ml) and large dosage of P₅ (200μg/ml) descend the IC₅₀ of DDP from 4.96μg/ml to 2.54μg/ml～2.37μg/ml on COC1/DDP, that close the sensitivity cell line COC1' IC₅₀;3. By Hoechst staining, small dosage of P₅ (25μg/ml) and large dosage of P₅ (200μg/ml) act with DDP, the cell apoptosis rate ascend clearly on COC1/DDP;4. ByFCM, the cells apoptosis rate of COC1/DDPis 0.06%, the G₁ stage proportion is 37.97%, the S stage proportion is 53.75%, the G₂/M stage proportion is 8.28%. Small dosage of P₅ has no clear effect to accelerate the apoptosis on COC1/DDP compared with control, but could descend the proportion of S stage, ascend the proportions of G₁ and G₂/M stages. Single DDP also has no effect to accelerate apoptosis rate on COC1/DDP compared with control, but ascend the cell's proportion of S stage and descend the proportion of G₁, G₂/M stages. Act small dosage of P5 (25μg/ml) with DDP (5μg/ml) on COC1/DDP cells, the apoptosis rate accelerated, the proportion of G₁ stage ascended, the proportion of S and G₂/M stages descended. Act large dosage of P₅ (200μg/ml) with DDP (5μg/ml), COC1/DDP has notable apoptosis rate, the G₁ stage proportion is descended and S, G₂/M stages proportion is ascended.Conclusion:Part 11. Single P₅ has no inhibitory effect to COC1;2. Small dosage of P₅ (25μg/ml) and large dosage of P₅ (200μg/ml) both could enhance the chemical sensitivity of DDP on COC1, and large dosage of P₅ has the better effect;3. The mechanism of P₅ enhancing DDP' chemical sensitivity may be correlated with the P₅'s effects of changing cell's cycle and increasing of DDP's apoptosis-inducing rate.Part 21. Single P₅ has no effect on COC1/DDP cells;2. Small dosage P₅(25μg/ml)and large dosage of P₅(200μg/ml) both could reverse the DDP resistance on COC1/DDP, and large dosage of P₅ has the better effect;3. The mechanism of P₅ reversing DDP' resistance may be correlated with the P₅'s effects of changing cell's cycle and increasing of DDP's apoptosis-inducing rate.