Epigenetic modulations are a hypothesized link between environmental factors and the development of psychiatric disorders. Research has suggested that patients with depression or bipolar disorder exhibit higher methylation levels in the glucocorticoid receptor gene NR3C1. We aimed to investigate whether NR3C1 methylation changes are similarly associated with externalizing disorders such as aggressive behavior and conduct disorder. NR3C1 exon 1F methylation was analyzed in young adults with a lifetime diagnosis of an externalizing disorder (N = 68) or a depressive disorder (N = 27) and healthy controls (N = 124) from the Mannheim Study of Children at Risk. The externalizing disorders group had significantly lower NR3C1 methylation levels than the lifetime depressive disorder group (p = 0.009) and healthy controls (p = 0.001) This report of lower methylation levels in NR3C1 in externalizing disorders may indicate a mechanism through which the differential development of externalizing disorders as opposed to depressive disorders might occur.
Epigenetic silencing of tumor suppressor genes is involved in early transforming events and has a high impact on colorectal carcinogenesis. Likewise, colon cancers that derive from chronically inflamed bowel diseases frequently exhibit epigenetic changes. But there is little data about epigenetic aberrations causing colorectal cancer in chronically inflamed tissue. The aim of the present study was to evaluate the aberrant gain of methylation in the gene promoters of VIM, TFPI2 and ITGA4 as putative early markers in the development from inflamed tissue via precancerous lesions toward colorectal cancer.
Initial screening of different cancer cell lines by using methylation-specific PCR revealed a putative colon cancer-specific methylation pattern. Additionally, a demethylation assay was performed to investigate the methylation-dependent gene silencing of ITGA4. The candidate markers were analyzed in colonic tissue specimens from patients with colorectal cancer (n = 15), adenomas (n = 76), serrated lesions (n = 13), chronic inflammation (n = 10) and normal mucosal samples (n = 9).
A high methylation frequency of VIM (55.6 %) was observed in normal colon tissue, whereas ITGA4 and TFPI2 were completely unmethylated in controls. A significant gain of methylation frequency with progression of disease as well as an age-dependent effect was detectable for TFPI2. ITGA4 methylation frequency was high in precancerous and cancerous tissues as well as in inflammatory bowel diseases (IBD).
The already established methylation marker VIM does not permit a specific and sensitive discrimination of healthy and neoplastic tissue. The methylation markers ITGA4 and TFPI2 seem to be suitable risk markers for inflammation-associated colon cancer.
