Figure 1.

Selection of HRT98G cells by repeated episodes of hypoxia. (A) Cell death assay using the trypan blue exclusion method was performed after the indicated cycles of repeated exposure to hypoxia and normoxia. (B) Immunoblot analysis for PARP and cleaved caspase-3 after the indicated cycles. P, parent cells (C) Sensitivity of HRT98G cells to different types of cytotoxic stimuli. T98G and HRT98G cells were exposed to 20 ng TNF-α for 4 h, 100 μM H₂O₂ for 24 h, 100 mJ/cm² UV for 24 h, and 20 μM etoposide for 12 h. Cell death was determined by the trypan blue exclusion method.