Fig. 2.

Intermittent hypoxia modulates ABCB1, ABCC1 and ABCA1 expression by changing C/EBP-β levels. NCI-H2228 cells were cultured as indicated in Fig. 1a. a Immunoblot of HIF-1α in whole cell extracts. Actin is included as control of equal protein loading. The image is representative of 1 out of 3 experiments. b EPO1, VEGFA, GLUT1, ABCB1, ABCC1, ABCA1 mRNAs, measured by RT-PCR, in technical triplicates. Data are means±SD (n = 4 biological replicates). *p < 0.05,**p < 0.01,***p < 0.001: H, H/N, H/N/H versus N cells; °°°p < 0.001: H/N cells versus H cells. c. Venn diagram representing the transcription factors binding ABCB1, ABCC1 and ABCA1 promoters (TRANSFAC software). d The expression levels of 38 transcription factors commonly binding ABCB1, ABCC1, ABCA1 promoters was measured by RT-PCR array and is represented in a colorimetric scale (n = 3 biological replicates). The expression of each transcription factor in normoxic cells was considered 1; the relative expression in the other experimental conditions is indicated in the heatmap