Hormone replacement therapy may protect against colon cancer.

2004 AUG 5 - (NewsRx.com & NewsRx.net) -- Hormone replacement therapy may protect against colon cancer.

"Epidemiological studies show a strong link between post-menopausal hormone replacement therapy and decreased incidence of colorectal cancer. The colon cancer cell line, COLO 205, develops sensitivity to 17beta-estradiol (E[subscript]2) in apoptosis assays with increasing passage number (>40), and we hypothesized that genes selectively regulated in multiply passaged cells were likely to be important in E[subscript]2-related apoptosis. Gene array analysis was used to compare the patterns of genes up- or down-regulated in E[subscript]2-sensitive and -insensitive cells," scientists writing in the Journal of Endocrinology report.

"For some genes, changes in mRNA expression were confirmed by protein expression analyses. Changes found in response to E[subscript]2 in multiply passaged cells, but not minimally passaged cells, included induction of growth arrest and DNA damage-inducible protein 153 (GADD153), and repression of Kirsten-Ras 2B (K-Ras-2B), metastasis inhibition factor NM23 and vascular endothelial growth factor," wrote Y. Qiu and colleagues, University of Birmingham, School of Medicine.

"A second group of genes was regulated with E[subscript]2 exposure in both cell types, and is unlikely to be critically involved in E[subscript]2-associated apoptosis. These included up-regulation of butyrate response factor 1 (BRF1) and down-regulation of c-jun and the breast cancer associated ring domain gene known as ...