Effect of hypoxia and/or paclitaxel or epirubicin on the c-jun mRNA expression level and AP-1 DNA binding activity. MDA-MB-231 cells were incubated under normoxic (N) or hypoxic (H) conditions with or without paclitaxel (tax, 50 μM) or epirubicin (epi, 10 μM) for 16 hours. (A) After incubation, total RNA has been extracted and retro-transcribed in cDNA. A real time PCR has been performed with specific primers for c-jun and for RPL13A, a house-keeping gene. Results are expressed in induction level by comparison with the reference condition, normoxia. (B) After the incubation, nuclear extracts were performed and hybridized in the ELISA well containing specific DNA probes (TransAM assay). Detection was performed using an anti-c-jun antibody. Results are expressed in absorbance, as mean ± 1 SD (n = 3). N.S. = non significantly different from control, *** = significantly different from control (p < 0.001); # = significant difference between N tax and H tax (p < 0.01), ### = significant difference between N tax and H tax (p < 0.001).