AIM: To establish the methylation profile of the promoter CpG islands of 31 genes that might play etiological roles in colon carcinogenesis.METHODS: The methylation specific PCR in conjunction of sequendng verificatio...AIM: To establish the methylation profile of the promoter CpG islands of 31 genes that might play etiological roles in colon carcinogenesis.METHODS: The methylation specific PCR in conjunction of sequendng verification was used to establish the methylationprofile of the promoter CpG islands of 31 genes in colorectal cancer (n = 65), the neighboring non-cancerous tissues (n = 5), colorectal adenoma (n = 8), and normal mucosa (n = 1). Immunohistochemically, expression of 10 genes was assessed on the home-made tissue microarrays of tissues from 58 patients. The correlation of tumor specific changes with each of clinical-pathologic features was scrutinized with relevant statistic tools.RESULTS: In comparison with the normal mucosa of the non-cancer patients, the following 14 genes displayed no tumor associated changes: breast cancer 1, early onset (BRCA1), cadherin 1, type 1, E-cadherin (epithelial) (CDH1),death-associated protein kinase 1 (DAPK1), DNA (cytosine-5-)-methyltransferase 1 (DNMT1), melanoma antigen, family A, 1 (directs expression of antigen MZ2-E) (MAGEA1), tumor suppressor candidate 3 (N33), cyclin-dependent kinase inhibitor 1A (p21, Cipl) (p21^WAF1), cyclin-dependent kinase inhibitor 1B (p27, 10pl) (p27^WAF1), phosphatase and tensin hornolog (mutated in multiple advanced cancers 1) (PTEN), retinoic acid receptor, beta (RAR-, Ras association (RaIGDS/AF-6) domain family 1 C (RASSFIC), secreted frizzled-related protein 1 (SFRP1), tissue inhibitor of metalloproteinase 3 (Sorsby fundus dystrophy, pseudoinfiammatory) (TIMP3),and von HippeI-Lindau syndrome (VHL). The rest 17 targets exhibited to various extents the tumor associated changes.As changes in methylation of the following genes occurred marginally, their impact on the formation of colorectal cancer were trivial: adenomatous polyposis coli (APC) (8%, 5165),Ras association (RaIGDS/AF-6) domain family 1A (RASSFIA) (3%, 2/65) and cyclin-dependent kinase inhibitor 2A,alternated reading frame Co14~) (6%, 4/65). The following genes exhibited moderate changes in rnethylation: O-6rnethylguanine-DNA rnethyltransferase (MGMT) (20%, 13/65),rnutL hornolog 1, colon cancer, nonpolyposis type 2 (E. coli) (hMLH1) (18%, 12/65), cyclin-dependent kinase inhibitor 2A (melanoma, p16, inhibits CDK4) P16^NK4a) (10%, 10/65),rnethylated in tumor 1 (MINT1) (15%, 10/65), methylated in tumor 31 (MINT31) (11%, 7/65). The rest changed greatly in the rnethylation pattern in colorectal cancer (CRC): cyclin A1 (cyclin al) (100%, 65/65), caudal type homeobox transcriptdon factor 1 (CDX1) (100%, 65/65), RAR(85%, 55/65), myogenic factor 3 (MYOD1) (69%, 45/65),cyclin-dependent kinase inhibitor 2B (p15, inhibits CDK4)(p15^INK4b) (68%, 44/65), prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase) (COX2) (72%, 47/65), cadherin 13, H-cadherin (heart) (CDH13) (65%, 42/65), CAAX box 1 (OO~/) (58%, 38/65),tumor protein p73 (p73) (63%, 41/65) and Wilrns tumor 1 (WT/) (58%, 38/65). However, no significant correlation of changes in rnethylation with any given clinical-pathological features was detected. Furthermore, the frequent changes in rnethylation appeared to be an early phase event of colon carcinogenesis. The in situ expression of 10 genes was assessed by the irnrnunohistochernical approach at the protein level: CDH1, CDH13, COX2, cyclin A1, hMLH1,MGMT, p14^ARF, p73, RAR-, and TIMP3 genes in the context of the rnethylation status in colorectal cancer. No clear correlation between the hyperrnethylation of the promoter CpG islands and the negative expression of the genes was established.CONCLUSION: The methylation profile of 31 genes was established in patients with colon cancer and colorectal adenornas, which provides new insights into the DNA rnethylation mediated mechanisms underlying the carcinogenesis of colorectal cancer and may be of prognostic values for colorectal cancer.展开更多
基金Supported by the National High Technology Research and DevelopmentProgram of China (863 Program),No.2002AA2Z3352,the ScienceFoundation of Shanghai Municipal Government,No.02DJ14056,and the Special Fund set up by the State-Key Laboratory for Oncogenes
文摘AIM: To establish the methylation profile of the promoter CpG islands of 31 genes that might play etiological roles in colon carcinogenesis.METHODS: The methylation specific PCR in conjunction of sequendng verification was used to establish the methylationprofile of the promoter CpG islands of 31 genes in colorectal cancer (n = 65), the neighboring non-cancerous tissues (n = 5), colorectal adenoma (n = 8), and normal mucosa (n = 1). Immunohistochemically, expression of 10 genes was assessed on the home-made tissue microarrays of tissues from 58 patients. The correlation of tumor specific changes with each of clinical-pathologic features was scrutinized with relevant statistic tools.RESULTS: In comparison with the normal mucosa of the non-cancer patients, the following 14 genes displayed no tumor associated changes: breast cancer 1, early onset (BRCA1), cadherin 1, type 1, E-cadherin (epithelial) (CDH1),death-associated protein kinase 1 (DAPK1), DNA (cytosine-5-)-methyltransferase 1 (DNMT1), melanoma antigen, family A, 1 (directs expression of antigen MZ2-E) (MAGEA1), tumor suppressor candidate 3 (N33), cyclin-dependent kinase inhibitor 1A (p21, Cipl) (p21^WAF1), cyclin-dependent kinase inhibitor 1B (p27, 10pl) (p27^WAF1), phosphatase and tensin hornolog (mutated in multiple advanced cancers 1) (PTEN), retinoic acid receptor, beta (RAR-, Ras association (RaIGDS/AF-6) domain family 1 C (RASSFIC), secreted frizzled-related protein 1 (SFRP1), tissue inhibitor of metalloproteinase 3 (Sorsby fundus dystrophy, pseudoinfiammatory) (TIMP3),and von HippeI-Lindau syndrome (VHL). The rest 17 targets exhibited to various extents the tumor associated changes.As changes in methylation of the following genes occurred marginally, their impact on the formation of colorectal cancer were trivial: adenomatous polyposis coli (APC) (8%, 5165),Ras association (RaIGDS/AF-6) domain family 1A (RASSFIA) (3%, 2/65) and cyclin-dependent kinase inhibitor 2A,alternated reading frame Co14~) (6%, 4/65). The following genes exhibited moderate changes in rnethylation: O-6rnethylguanine-DNA rnethyltransferase (MGMT) (20%, 13/65),rnutL hornolog 1, colon cancer, nonpolyposis type 2 (E. coli) (hMLH1) (18%, 12/65), cyclin-dependent kinase inhibitor 2A (melanoma, p16, inhibits CDK4) P16^NK4a) (10%, 10/65),rnethylated in tumor 1 (MINT1) (15%, 10/65), methylated in tumor 31 (MINT31) (11%, 7/65). The rest changed greatly in the rnethylation pattern in colorectal cancer (CRC): cyclin A1 (cyclin al) (100%, 65/65), caudal type homeobox transcriptdon factor 1 (CDX1) (100%, 65/65), RAR(85%, 55/65), myogenic factor 3 (MYOD1) (69%, 45/65),cyclin-dependent kinase inhibitor 2B (p15, inhibits CDK4)(p15^INK4b) (68%, 44/65), prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase) (COX2) (72%, 47/65), cadherin 13, H-cadherin (heart) (CDH13) (65%, 42/65), CAAX box 1 (OO~/) (58%, 38/65),tumor protein p73 (p73) (63%, 41/65) and Wilrns tumor 1 (WT/) (58%, 38/65). However, no significant correlation of changes in rnethylation with any given clinical-pathological features was detected. Furthermore, the frequent changes in rnethylation appeared to be an early phase event of colon carcinogenesis. The in situ expression of 10 genes was assessed by the irnrnunohistochernical approach at the protein level: CDH1, CDH13, COX2, cyclin A1, hMLH1,MGMT, p14^ARF, p73, RAR-, and TIMP3 genes in the context of the rnethylation status in colorectal cancer. No clear correlation between the hyperrnethylation of the promoter CpG islands and the negative expression of the genes was established.CONCLUSION: The methylation profile of 31 genes was established in patients with colon cancer and colorectal adenornas, which provides new insights into the DNA rnethylation mediated mechanisms underlying the carcinogenesis of colorectal cancer and may be of prognostic values for colorectal cancer.
