1. HIF-1α is critically involved in hypoxia-induced CD137 upregulation.
HIF-1α is critically involved in hypoxia-induced CD137 upregulation. A, FACS time course analyses of surface CD137 expression on OT-1 and OT-2 T-cell cultures conducted under normoxia, hypoxia, or in the presence of 0.2 mmol/L DMOG. A bar graph representing CD137 mRNA expression referred to β-actin at 12 hours of culture in the presence or absence of DMOG is presented under each corresponding time course graph. B, transgenic mice carrying a Cre recombinase that translocates to the nucleus in the presence of tamoxifen (control) or carrying this transgene together with floxed/floxed Hif-1α alleles (Hif-1αfloxed/floxed) were treated with tamoxifen for 5 days and spleens were harvested 7 days later. Histograms represent CD137 immunostaining on CD3+CD4+ and CD3+CD8+ lymphocytes from 48-hour cultures from these splenocytes stimulated by plate-bound anti-CD3 mAbs and set up either under hypoxic (red line) or normoxic (blue line) conditions as indicated (left). The right bar graph represents the CD137 mRNA in parallel cultures analyzed at 12 hours. C, time course FACS analysis of surface CD137 expression on splenocytes derived from tamoxifen-treated control transgenic mice or mice induced to become HIF-1α–deficient as in (B). Cultures stimulated by plate-bound anti-CD3 mAbs were set up in the presence or absence of 0.2 mmol/L DMOG and were analyzed at the indicated time points. The mRNA levels at 12 hours are presented in the corresponding bar graphs. Results represent individual mice of 5 independent experiments rendering comparable results. Quantitative RT-PCR experiments show mean ± SD of triplicate samples.
Asís Palazón et al. Cancer Discovery 2012;2:
©2012 by American Association for Cancer Research