Expression analysis of a subset of coregulators and three nuclear receptors in human colorectal carcinoma.

In human colorectal tissue samples, the gene expressions of 4 coactivators, p300, pCAF, TIF-2 and TRAP 220, and 7 corepressors, N-CoR, REA, MTA1, MTA1L1, HDAC1, HDAC2 and HDAC3, linked to estrogen receptors (ER), were revealed by traditional RT-PCR. Cofactors ERalpha, ERbeta and ERRalpha mRNA levels were then measured in 40 tumor tissue samples matched with respective normal mucosa by real-time PCR. The decline of mRNA levels of all coactivators and the increase of NCoR, HDAC1, HDAC2 and MTA1 were observed from normal to tumor tissue, whereas REA, HDAC3 and MTA1L1 expressions were similar in both tissue compartments. The gene expression of ERbeta correlated with those of p300, TIF-2 and REA in normal mucosa, and with that of REA in tumor tissue only. No association was found between ERalpha and coregulators and between each coregulator and different clinical parameters. Our findings suggest that the co-induction of ERbeta and some cofactors may play an important role during the development of human colorectal carcinoma.