Fig. 6

a direct correlation (linear regression) between drug synergism of trabectedin and olaparib in combination (1 - combination index) and PARP1 protein expression (western blot image quantitation) in 11 human tumor cell lines with different origin (Additional file 1: Table S2); Pearson score r and P value are indicated; b western blot analysis of PARP1 and actin (as housekeeping) protein expression in cells stably transduced with lentiviral vector carrying PARP1 specific shRNA for silencing or functional PARP1 gene for overexpression; c cell viability assay in PARP1 stably silenced (shPARP1) HS-C TC-106 and 402.91 cells and their parental wild type (wt) counterparts; d cell viability assay in LS-C (SJSA-1 and SW684) overexpressing PARP1 (overPARP1) and their parental wild type (wt), Y error bars indicate mean ± S.E.M; *** p < 0.001 between combination and both single agents and controls