Expression patterns of ARNT and COX-2 in surgical specimens of cervical
carcinoma. A, representative pictures of cervical cancer samples
at different ARNT/COX-2 grades. The triple-immunofluorescent stain technique
was used to identify ARNT (green), COX-2 (red), and nucleus
(blue) in cervical cancer tissues. Scale bar, 5 μm.
B, a linear correlation (R = 0.81) of ARNT and COX-2
expression in the same surgical specimen of cervical cancer tissues. The case
number is indicated in parentheses beside each point. C,
total RNA from tumor and normal tissue of different human cervical cancer
patients (#1 to #3) was extracted for reverse transcription
PCR with COX-2, ARNT, and glyceraldehyde-3-phosphate dehydrogenase
primers. D, schematic pathway of COX-2 promoter regulation
by EGF stimulation. Activation of EGFR signaling increases nuclear
accumulation of ARNT under normoxic conditions. ARNT then interacts with
transcriptional factor c-Jun and binds to the CRE site, which results in an
increase of COX-2 expression and tumorigenesis.