Haplotype insufficiency for suppressor of cytokine signaling-2 enhances intestinal growth and promotes polyp formation in growth hormone-transgenic mice

Michaylira, CZ; Ramocki, NM; Simmons, JG; Tanner, CK; McNaughton, KK; Woosley, JT; Greenhalgh, CJ; Lund, PK

Author(s): Michaylira, CZ; Ramocki, NM; Simmons, JG; Tanner, CK; McNaughton, KK; Woosley, JT; Greenhalgh, CJ; Lund, PK;
Details: Publication Year 2006-04,Volume 147,Issue #4,Page 1632-1641
Journal Title: ENDOCRINOLOGY
Publication Type: Journal Article
Abstract: GH may improve intestinal growth or function in patients with short bowel syndrome. Excessive trophic effects of GH or IGF-I may contribute to neoplastic growth or increased colorectal cancer risk in acromegaly. Identification of mechanisms that limit the tumorigenic potential of GH and IGF- I is desirable. Suppressor of cytokine signaling-2 (SOCS2) limits GH action on body and organ growth, but its role in GH action on intestine is unknown. We tested the hypothesis that SOCS2 limits GH-induced intestinal growth or neoplasia in vivo. GH transgenic (GH-TG) mice were crossed with SOCS2 null mice to generate wild-type (WT) or transgenic (TG) mice with zero (HO-WT; HO-TG), one (HT-WT; HT-TG), or two (WT-WT; WT-TG) functional SOCS2 genes. No HO-TG mice were derived from crossbreeding. WT-WT, HT-WT, WT-TG, and HT-TG were compared. Body weight, small intestine and colon growth, and levels of jejunal IGF-I and sucrase-isomaltase mRNAs were assessed. Colon was analyzed for abnormal lesions. HT-WTdid not differ from WT-WT. Compared with WT-TG, HT-TG had significantly increased body weight, small intestine growth, and local IGF-I expression and decreased sucrase-isomaltase expression. HT-TG colon spontaneously developed multiple hyperplastic and lymphoid polyps. GH-induced activation of STAT5 DNA binding activity was enhanced in intestine of SOCS2 null mice compared with WT control. Haplotype insufficiency for SOCS2 promotes trophic actions ofGHin small intestine and promotes preneoplastic growth in colon during excess GH. Small variations in SOCS2 expression levels may significantly influence the outcome of therapeutic GH or acromegaly in intestine.
Publisher: ENDOCRINE SOC
Keywords: SHORT-BOWEL SYNDROME; FACTOR-I; INSULIN; CANCER; SOCS; RAT; GH; DIFFERENTIATION; NUTRITION; CHILDREN
Publisher's Version: https://doi.org/10.1210/en.2005-1241
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2006-04-01 12:00:00