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Suppressor of cytokine signaling-2 gene disruption promotes Apc(Min/+) tumorigenesis and activator protein-1 activation
- Source :
- The American journal of pathology. 176(5)
- Publication Year :
- 2010
-
Abstract
- Epigenetic in vitro and in vivo studies suggest that suppressor of cytokine signaling-2 (SOCS2) may normally limit tumorigenesis in the intestine; however, this theory has not been directly tested. We hypothesized that SOCS2 deficiency promotes spontaneous intestinal tumorigenesis in Apc(Min/+) mice. Therefore, we quantified tumor number, size, and load in the small intestine and colon using SOCS2(+/+)/Apc(Min/+), SOCS2(+/-)/Apc(Min/+), and SOCS2(-/-)/Apc(Min/+) mice and assayed hematocrit as an indirect marker of disease severity. Biochemical and histological assays were used to assess mechanisms. Heterozygous and homozygous disruption of SOCS2 alleles promoted 166 and 441% increases in tumor load in the small intestine, respectively, accelerated development of colon tumors, and caused severe anemia. SOCS2 deletion promoted significant increases in intestinal insulin-like growth factor-I mRNA but did not affect plasma insulin-like growth factor-I. Western blots and immunohistochemical analysis demonstrated that tumor and nontumor intestinal tissue of SOCS2(-/-)/Apc(Min/+) mice had increased serine 727 phosphorylation of signal transducer and activator of transcription 3 compared with SOCS2(+/+)/Apc(Min/+) mice. Moreover, electromobility shift assays showed that SOCS2 deletion did not alter signal transducer and activator of transcription 3 DNA binding. However, tumors and small intestine from SOCS2(-/-)/Apc(Min/+) showed dramatic increases in activator protein-1 (AP-1) DNA binding, and SOCS2 overexpression in vitro reduced levels of AP-1. These studies indicate that SOCS2 deletion promotes the spontaneous development of intestinal tumors driven by mutations in the adenomatous polyposis coli/beta-catenin pathway and activates AP-1. Therefore, reduced expression or epigenetic silencing of SOCS2 may serve as a useful biomarker for colorectal cancer risk.
- Subjects :
- Male
Genes, APC
Adenomatous polyposis coli
medicine.medical_treatment
Mice, Transgenic
Suppressor of Cytokine Signaling Proteins
medicine.disease_cause
Pathology and Forensic Medicine
Epigenesis, Genetic
Mice
medicine
Biomarkers, Tumor
Gene silencing
Animals
Gene Silencing
SOCS2
Alleles
biology
Activator (genetics)
Homozygote
Molecular biology
Small intestine
Gene Expression Regulation, Neoplastic
Mice, Inbred C57BL
Transcription Factor AP-1
medicine.anatomical_structure
Cytokine
biology.protein
STAT protein
Cancer research
Carcinogenesis
Gene Deletion
Regular Articles
Subjects
Details
- ISSN :
- 15252191
- Volume :
- 176
- Issue :
- 5
- Database :
- OpenAIRE
- Journal :
- The American journal of pathology
- Accession number :
- edsair.doi.dedup.....b1950e18e0f30653d425f1d97591df61