Differential Gene Expression on Human LNCaP Cells Following Treatment with DHEA versus DHT

ABSTRACT The effects of DHEA were compared with those of DHT using gene expression array profiles in human LNCaP prostate cancer cells. LNCaP cells were exposed to DHEA (300 nM), DHT (300 nM), or vehicle for 48 hrs, and mRNA was isolated. mRNA expression was measured using Affymetrix HU-95 gene chips in 3 experiments performed on different dates. Gene expression values for the two treatment groups and control were sorted in ascending order on the p-values corresponding to a variance stabilized Hotelling test, which measured the extent of differential RNA expression between control and either hormone treatment. The top four genes with significant differential expression were S100 calcium binding protein, neurotensin, 24-dehydrocholesterol reductase, and anterior-gradient 2 homologue. Corresponding per comparison p-values were less than 3 x 10 -5. Nested tests of differential expression between DHEA and DHT treatment revealed significant differences (p < 0.01) for two of the four genes: the S100 calcium binding protein and neurotensin. The microarray findings were confirmed by quantitative RT-PCR. The top 83 genes found to exhibit differential expression were used in a pathway analysis. In general, DHT decreased expression of more genes involved in intercellular communication, signal transduction, nucleic acid binding and transport, and in structural components, such as myosin and golgin, than did DHEA. These data reveal consistent, measurable differences in gene expression patterns following treatment of LNCaP prostate cancer cells with DHEA versus DHT. The mechanisms underlying these observations, and the possible pathophysiological significance of these differences, remain to be determined. Keywords: differential gene expression between DHT and DHEA Three separate experiments were performed and labeled: 111502, 011403, and 022803. Three groups were run per experiment: Control, DHT or DHEA. Cells were exposed for 48 hr to 300 nM of DHT or DHEA. One Affymetrix HG_U95Av2 microarray chip per group was analyzed. The data was normalized by the "dchip" process.