The Effect Of Diclofenac On The Sensitivity To Chemotherapy Drug In Platinum-resistant Ovarian Cancer Cell Line COC1/DDP

Background and ObjectiveThe mortality rate of ovarian caner plays the first place in female genitalmalignant tumor, the incidence is gradually increasing. With the development ofmedical level, surgical skills and chemotherapy of ovarian cancer have improved, butmany patients experience failure of treatment and an early relapse because of drugresistance, especially the platinum-resistant, which has serious impacts on theprognosis of ovarian cancer patients. Currently, the mechanism of drug resistancehave no consensus, Vijay Alla et al propose that E2F1-p73/DNp73-miR-205axis canbe considered as a key mechanism for chemoresistance. Epidemiological studies havesuggested that the regular use of non-steroidal anti-inflammatory drugs (NSAIDs)was associated with a reduced risk of various cancers, including colorectal, breast,lung and ovarian cancers. Studies have shown that in vitro, diclofenac andindomethacin reduced tumor volume in a xenograft model of ovarian cancer andE2F1was downregulated at the mRNA and protein level upon treatment withdiclofenac and indomethacin, furthermore, indomethacin might fight the resistance ofoxaliplatin, and might play a role to reverse platinum-resistant in lung cancer.E2F1is a unique member of the E2F family, its basic function is to participate incell cycle from G1to S phase regulation, and to regulate apoptosis pathway through p53-dependent and p53-independent pathways. Simultaneously, it also participates ina variety of physiological and pathological processes, and has close relationship to thetumor. The role of E2F1in the process of tumor formation, depends on the balance ofthese two effects, and is related with the test conditions and organ specificity. Studiesdiscover that the expression of E2F1is higher in ovarian cancer tissue, and it willreduce when affected by non-steroidal anti-inflammatory drugs. More studies shouldbe made on the way how E2F1gets expressed in platinum-resistant ovarian cancercells as well as how it changes when affected by non-steroidal anti-inflammatorydrugs.This study adopted MTT to detect the growth inhibition of COC1/DDP, FlowCytometry to detect the apoptosis rate of COC1/DDP and Immunocytochemistry todetect the expression of E2F1in parental cell COC1and COC1/DDP cell line. Theaims are to explore the effect of the growth inhibition and the sensitivity to cisplatinof low concentrations of diclofenac and diclofenac in combination with cisplatin inovarian cancer platinum-resistant cell line COC1/DDP, and to explore the changes ofthe expression of E2F1after affected by diclofenac, and provide a reference inlooking for an effective target for platinum-resistant targeted therapy.Materials and MethodsThe cell inhibition rates and50%inhibition concentration (IC50) were measuredby MTT after affected by cisplatin and by cisplatin in combination with diclofenac.Cell apoptosis were detected by flow cytometry after affected by diclofenac, bycisplatin and by cisplatin in combination with diclofenac. The expression of E2F1protein was analyzed using Immunocytochemistry in parental cell COC1andCOC1/DDP cell line, and the expression in COC1/DDP cell line after affected bydifferent concentrations of diclofenac for48hours and by diclofenac in50mol/L for72hours.Statistical analysis: All dates were analysised by SPSS17.0statistical software.Inspection level a=0.05.Results1. The inhibition rates of COC1/DDP cell after affected by diclofenac alone for48hours, there is statistically significant difference. And then pairwise comparison, there is no significant difference of these drug concentrations among10mol/L,30mol/L and50mol/L(P>0.05). There is statistically significant difference betweenthese drug concentrations of70mol/L and90mol/L and the above three groups(P<0.05).2. The IC50for COC1/DDP cell of cisplatin is8.39g/ml after affected bycisplatin alone for48hours, and the IC50for COC1/DDP cell of cisplatin is4.35g/ml after affected by cisplatin in combination with diclofenac for48hours, thedifference of two inhibition rates is statistically significant (P<0.05).3. The apoptosis rate for COC1/DDP cell is (2.850.37%) after affected bydiclofenac (50mol/L) alone for48hours, and the apoptosis rate for COC1/DDP cellis (12.740.45)%after affected by cisplatin (4g/ml) alone for48hours, and theapoptosis rate for COC1/DDP cell is (23.780.49)%after affected by cisplatin incombination with diclofenac for48hours, the difference of inhibition rates isstatistically significant (P<0.05).4. The expression of E2F1in ovarian cancer COC1cell is less than inCOC1/DDP cell, the difference is statistically significant (P<0.05).5. The expression of E2F1in COC1/DDP cell declines after affected by differentconcentrations of diclofenac for48hours, and the higher the concentration is, the lessthe expression of E2F1will be, the difference is statistically significant (P<0.05). Andfind that the range of reduction is the largest when the concentration of diclofenac is50mol/L.6. The expression of E2F1in COC1/DDP cell after affected by diclofenac in50mol/L for72hours is less than for48hours, the difference is statisticallysignificant (P<0.05).Conclusions1. There is no significant cytotoxicity for platinum-resistant ovarian cancer cellline COC1/DDP after affected by low concentrations of diclofenac.2. Diclofenac can increase the sensitivity of cisplatin in platinum-resistantovarian cancer cell line COC1/DDP, and increase the apoptosis rate. 3. The expression of E2F1in COC1/DDP cell is higher than that in ovariancancer COC1cell, the higher expression of E2F1may be closely associated withplatinum-resistance.4. The expression of E2F1in platinum-resistant ovarian cancer cell lineCOC1/DDP cell after affected by diclofenac is in time-dependent and concentration-dependent manner, diclofenac can increase the sensitivity of cisplatin in COC1/DDPthat may result from the decreased expression of E2F1.