Fig. 4

Loss of DNA-PKcs kinase activity promotes the expansion SSEA4⁺ progenitor cells and senescence-associated transcripts. Lung fibroblasts were cultured and treated with 500 nM of Nu7441 every 3 days for a total of 25 days. As a control, untreated fibroblasts were utilized. a-b Shown are representative images of untreated (a) or 25-day Nu7441 treated (b) lung fibroblasts. c After 25 days, lung fibroblasts were trypsinized and stained with anti-SSEA4 antibodies. Shown are representative dot plots depicting SSEA4⁺ cells within untreated (C, left) and 25-day Nu7441 treated (C, right) fibroblast cultures. d Shown is the mean percentage of SSEA4⁺ cells in untreated and 25-day Nu7441 treated fibroblast cultures. Data shown are mean ± s.e.m.; n = 4. *p ≤ 0.05 via Mann-Whitney two-tailed non-parametric test. e-g Twenty-five days after culture with or without Nu7441, RNA was extracted from lung fibroblasts and qPCR analysis was performed for myofibroblast (e), senescence and stress-associated (f) and inflammatory (g) transcripts. Depicted is the average fold change of expression of Nu7441 relative to vehicle treated lung fibroblasts. n = 4; *p ≤ 0.05 via Mann-Whitney two-tailed non-parametric test