Methylation status of T-lymphoma invasion and metastasis 1 promoter and its overexpression in colorectal cancer.

T-lymphoma invasion and metastasis 1 has been implicated in tumor invasion and metastasis. However, the regulatory mechanisms underlying aberrant T-lymphoma invasion and metastasis 1 expression in human colorectal cancer have not been well defined. To investigate the relationship between methylation status and expression levels of T-lymphoma invasion and metastasis 1 gene, methylation-specific polymerase chain reaction, and immunohistochemistry staining were performed in 232 matched samples of human colorectal cancer tissue and normal colorectal mucosa. Results showed that T-lymphoma invasion and metastasis 1 protein was overexpressed in colorectal cancer, especially in metastatic cases (P < .001). The degree of T-lymphoma invasion and metastasis 1 promoter methylation was a little lower in cancer tissues than in matched normal mucosa (P < .05), and the expression level of T-lymphoma invasion and metastasis 1 was inversely related to the methylation status in cancer tissues (P < .001). Colon cancer cell lines HT29 and LS174T were treated with demethylating agent 5-aza-2'-deoxycytidine, resulting in promoter hypomethylation accompanied by reexpression of T-lymphoma invasion and metastasis 1 mRNA and protein. In contrast, colon cancer cell lines SW620 and LoVo were treated with hypermethylation agent S-adenosylmethionine, resulting in T-lymphoma invasion and metastasis 1 promoter hypermethylation, accompanied by suppression of T-lymphoma invasion and metastasis 1 expression and inhibition of cell growth, plate colony formation, and migration. The present study demonstrates that overexpression of T-lymphoma invasion and metastasis 1 is associated with hypomethylation status of T-lymphoma invasion and metastasis 1 promoter region in colorectal cancer tissues. It suggests that promotor hypomethylation of T-lymphoma invasion and metastasis 1 may play a role in the progression and metastasis of colorectal cancer. Pharmacologic reversal of T-lymphoma invasion and metastasis 1 promoter hypomethylation may inhibit cell proliferation and migration.