Figure 3

DNA damage and cell cycle arrest in cells treated with MST-312. (A) The extent of DNA damage in cells treated with 1.0 μM MST-312 for 48 hours represented by tail moment. A significant increase in DNA damage was observed in all the cell types. (B) Extent of double strand breaks was measured using detection of γH2AX foci and Increase in formation of DSBs in all cell types was observed following 48 hours of 1.0 μM MST-312. (C) Telomere dysfunction induced foci (TIF) analysis following treatment with 1.0 μM MST-312 for 24 and 48 hours in MRC-5, ONS76 and KNS60 cells. Significant increase in the number of cells with TIFs (yellow foci) was observed following MST-312 treatment in ONS76 and KNS60 cells compared to that in MRC-5 cells. Images were captured using a Zeiss Axioplan Imaging fluorescent microscope with 63 × objective and are processed using Adobe Photoshop CS2 (Adobe Systems Incorporated, USA) for clarity and illustration. (D) Decrease in survival of cells was observed in all cells tested following MST-312 concentration as indicated for 48 hours. (E) Flow cytometry analysis of cell cycle profiles in MST-312-treated cells. MO59K and KNS60 cells showed significant increase in G2/M and apoptotic cell population. On the contrary, there was significant increase in G1 population in ONS76 cells following MST-312 treatment.