Supplementary information Supplementary Figures: Supplementary Fig.S1 TCRP1 is involved in DDP resistance in lung cancer cells. The mRNA expression levels of TCRP1 were detected by real-time RT-PCR in A549 and A549/DDP cells (A), A549/DDP cells transfected with siRNA of TCRP1 or control (B), and A549 cells transfected with pcDNA3.1-TCRP1 or control plasmid (C). p<0.05 (t test). Supplementary Fig.S2 The effect of siRNA knockdown was checked by using western blot. (A) The TCRP1 siRNA and control scrambled interfering RNA were transfected in A549/DDP cells for 48 h and the TCRP1 expression was detected using western blotting. (B) The Pol β expression was tested using western blotting after the treatment of Pol β siRNA or control siRNA in A549/DDP cells for 48 h. Supplementary Fig.S3 Quantitative data of γ-H2AX foci in Pol β-knockdown A549/DDP cells with DDP treatment. Pol β knockdown or control A549/DDP cells were cultured with 3 μg/ml of DDP for 24 h and γ-H2AX foci formation was examined by immunofluorescence staining. γ-H2AX foci from 600 single cells was quantified and categorized into the indicated groups. *P <0.05 (t test). Supplementary Tables: Supplementary table 1 siRNA sequences used in this study Name Sequences siTCRP1-1 5’-CCGAGAACCGAACUUACCA-3’ siTCRP1-2 5’-UCUGCGGCUUUCAGAUAUA-3’ siTCRP1-3 5’-GACCGAGAACCGAACUUAC-3’ siPol β-1 5’-GAUACGAGUUCAUCCAUCA-3’ siPol β-2 5’-GACUCGAGUUAGUGGCAUU-3’ siPol β-3 5’-GAACUCGCAAACUUUGAGA-3’