(a–b) THS exposure (1:80) increases cell proliferation assessed by MTT assay in H460 cells (a) and H510 cells (b). Significance was obtained using t-test at each timepoint in comparison to control treated cells (* P-value<0.05; ** P-value<0.01). (c–d) THS exposure (1:80) increases clonogenic potential of H460 cells (c) and H510 cells (d). Representative cell culture plates of control and THS treated cells are shown on the left. Quantitation of the total number and relative size of individual colonies is shown on the right. Significance was obtained using Chi-square test in comparison to control treated cells (* P-value<0.05; ** P-value<0.01; NS: not significant)