Figure 3. CAXII and Pgp expression levels are affected by HIF-1α in chemoresistant cells.

(A) The CAXII mRNA level in HT29 and HT29/dx cells was detected by qRT-PCR. Data are presented as means ± SD (n = 4). Versus HT29: *p < 0.001. (B) EMSA detection of HIF-1α bound to its DNA consensus sequence was performed on nuclear extracts of normoxic HT29 and HT29/dx cells. Hypoxic HT29 cells (grown at 2% O₂ for 24 h) were used as positive control of HIF-1α activation (+). One lane was loaded with distilled water in place of cell extracts and was used as negative control (−). As control of specificity, the nuclear extracts of hypoxic HT29 cells were incubated with an anti-HIF-1α antibody (Ab HIF-1α). The band corresponding to the HIF-1α-DNA complex is indicated by the arrow. The figure is representative of three experiments with similar results. (C–E) mRNA was extracted from wild-type HT29 cells and HT29/dx cells (CTRL), HT29/dx cells treated with a non targeting scrambled siRNA (scr) or with a HIF-1α-targeting specific siRNA pool (siHIF) for 24 h. The expression of HIF-1α (panel C), CAXII (panel D) and Pgp (panel E) was detected by qRT-PCR. Data are presented as means ± SD (n = 4). Versus CTRL HT29: *p < 0.001; versus CTRL HT29/dx: ° p < 0.001.