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. 2017 Sep 1;12(9):e0184135. doi: 10.1371/journal.pone.0184135

Fig 2. Low-dose pemetrexed plus cisplatin synergistically work to inhibit survival and induce apoptosis in human choroidal melanoma cells.

Fig 2

(A) OCM1 and (B) M619 cells were seeded in 96-well plates and treated with increasing doses of pemetrexed combined with various doses of cisplatin respectively for 24 hours. The IC50 values for the individual components and the drug combination were calculated using GraphPad Prism 5.0 software. The IC50 values for pemetrexed and cisplatin were 21.04μM and 37.87μM respectively while the values were 4.847μM, 2.95μM and 1.77μM for various concentrations of drug combination respectively in OCM1 cells. Meanwhile, the IC50 values for pemetrexed and cisplatin were 46.38μM and 56.62μM respectively and the values were 2.911μM, 1.512μM and 0.8627μM for various concentrations of drug combination respectively in M619 cells. (C, D) The synergistic effect of pemetrexed and cisplatin was analyzed using isobolograms. X-axes represented for cisplatin concentration while y-axes represented for pemetrexed concentration. An isobole was constructed by joining the points that represented the IC50 values of pemetrexed and cisplatin, and the dots underlying the isobole represented the IC50 values of the combination treatment. (E, F, G) OCM1 and M619 cells were treated with various concentrations of the chemotherapeutic drugs for 24 hours and then harvested for western blotting and apoptosis analysis. CF: cleaved form. CFs: plural of cleaved form. All data are presented as the mean ± S.D.