Published in:
01-06-2004 | Original Contribution
Effects of Estrogen on Messenger Ribonucleic Acid Expression Patterns of Extracellular Matrix Proteases in the Primate Colon
Authors:
Steven Mills, M.D., Kelly A. Young, Ph.D., Mark H. Whiteford, M.D., F.A.C.R.S.
Published in:
Diseases of the Colon & Rectum
|
Issue 6/2004
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PURPOSE:
Recent studies suggest that hormone replacement therapy in postmenopausal women can decrease colon cancer risk. To better understand the molecular effects of estrogen on the colon, we examined the effects of estrogen replacement on gene expression of proteases associated with extracellular matrix degradation in rhesus monkey colon tissue.
METHODS:
Rhesus monkeys were oophorectomized and one-half were implanted with estradiol capsules. After five months, colon tissue was harvested, and messenger ribonucleic acid was extracted and converted to cDNA. The cDNA was hybridized with a DNA array spotted with cDNA corresponding to genes involved in extracellular matrix remodeling. Selected genes exhibiting significant differential expression were validated using reverse transcriptase-polymerase chain reaction and real-time polymerase chain reaction analysis.
RESULTS:
Of 96 genes assessed, nearly 18 percent showed a twofold or greater change in expression; however, signals from approximately 65 percent of genes assayed were below detection levels. A distinct pattern of decreased gene expression was observed in colon tissue of animals with estrogen implants compared with females without estrogen replacement. Reverse transcriptase-polymerase chain reaction confirmed decreased expression in estrogen-replaced vs. hormone-deprived tissues of proteases cathepsin-D and caspase-8. Real-time polymerase chain reaction data confirmed the suppression of proteases A disintegrin and mettaloproteinase with thrombospondin motifs, type 1 and matrix metalloproteinase-2 with estrogen replacement in colon tissue.
CONCLUSIONS:
This is the first investigation of the specific effects of estrogen in normal primate colon. Estrogen replacement suppressed expression of several proteases linked to tumor growth and metastasis. This study provides the groundwork for targeted future studies to further characterize the role of estrogen in colon tissue.