Figure 3

Radiation induced mitochondrial biogenesis augments metabolic viability: (A) Cell cycle histogram showing phase distribution (G1, S and G2/M) of cells at 24 and 48 hrs post irradiation in HeLa and MDA-MB-231 cells. (B) Mitochondrial genome encoded Leu tRNA gene was analyzed by semi quantitative PCR and normalized with nuclear pol gamma gene copy number. The mtDNA copy number is also presented as comparative fold change at respective time points (bar diagram). (C) Protein expression analysis of mitochondrial biogenesis and mitochondrial complex-II subunit SDH-A presented in HeLa and MDA-MB-231 cells. The values between the blots represent the fold increase at 8 and 24 hrs. post irradiation quantified by densitometry and normalized with respective β-Actin. The DNA (B) and protein blot (C) images were cropped from full-length blots (Supplementary Figs 2 and 3). (D) Analysis of effect of chloramphenicol (40 μM; 30 mins prior to IR; continuous exposure) on mitochondrial content by MitoTracker Green FM at indicated time points using flow cytometer and graphs presented as fold change of mean fluorescence intensity (MFI) with respective control. Effect of Chloramphenicol on radiation induced growth inhibition was analyzed (at 5 Gy) by MTT assay (E) and cell number (F) in HeLa and MDA-MB-231 cells. Growth inhibition quantified and mentioned at 48 hours. Data are expressed as mean ± SD from triplicates. *p < 0.05 vs. unirradiated control.