To test this hypothesis, we performed isobologram analyses around the ovarian cancer cell line 2008, that is deficient within the FA pathway on account of of the FANCF promoter, and on its isogenic, complemented FA pathway proficient coun terpart 2008 FANCF cell line. 1st, single agent survival curves were generated, as well as the dose producing a 50% reduction of cell survival was determined. As previously reported, 2008 cells were substantially additional sensitive to cisplatin than 2008 FANCF cells. 2008 and 2008 FANCF cells had been equally sensitive to all FA pathway inhibitors, except for puromycin and geldanamycin. Higher tolerance of 2008 FANCF cells to puromycin was likely due to the use of puromycin selec tion to generate the complemented cell line, and hence, puromycin was omitted from additional evaluation.
The purpose for the differential sensitivity of 2008 and 2008 FANCF cells toward geldanamycin remains unknown. Subsequent, isobolograms in the LD50 level pi3k beta inhibitor were generated following the method previously described. Survival assays were performed applying the combination of 10 cisplatin concentrations with six concentrations of every FA pathway inhibitor. LD50 LD500 unit values of each FA pathway inhibitor were plotted against corresponding LD50 LD500 unit values of cisplatin. The distribution of points along the line connecting values of 1 corresponds to an additive effect from the two drugs while scattering below or above represents synergism and antagonism, respectively. Furthermore, combination index values were calculated as outlined by Chou and Tallays strategy, CI 0. 90 indicates synergism.
Analyses performed at 50% killing revealed that 11 FA pathway inhibitors exhibited synergism with cisplatin in 2008 and or 2008 FANCF cells. Bortezomib, 17 AAG, CA 074 Me, and compounds 7012246 and 5373662 synergized with cisplatin in FA pathway proficient 2008 FANCF cells, but not in their isogenic FA pathway deficient AGI-5198 ic50 counterpart 2008, consistent with their FA pathway inhibition activity. Geldanamycin, 3 CHK1 inhibitors and chloroquine synergized with cisplatin in each 2008 and 2008 FANCF cells. Geldanamycin, UCN 01 and SB218078 exhibited a significantly stronger synergism in 2008 FANCF cells than in 2008 cells, once again consis tent with their FA pathway inhibition activity. Finally, lactacystin weakly synergized with cisplatin in 2008 cells only. The other compounds had either additive or antagonistic impact with cisplatin.
Analyses performed at 70% killing showed that bortezomib, cells.ALLN, and compounds synergized with cisplatin in 2008 FANCF only. Taken collectively, about half in the FA pathway inhibitors sensitized ovarian cancer cells to cisplatin and 12 of 25 at 70% killing. Most of them exhibit a significantly stronger synergism with cisplatin in FA pathway proficient 2008 FANCF cells than in 2008 cells for 8 of 11 drugs at 50% killing, for 9 of 12 drugs at 70% killing indicating that their effects are, a minimum of partially, mediated via inhibition with the FA pathway.