Mutations of DNA repair associated gene, APEX in human colorectal cancer.
- Author:
Sang Hwan OH
1
;
Hee Boong PARK
;
Yu Jin KIM
Author Information
1. AJOU UNIV, SCH MED, DEPT SURG, KYUNG KI DO, KYUNGKI DO 442749, SOUTH KOREA.
- Publication Type:Original Article
- Keywords:
mutations;
A P E X gene;
APE activity;
colorectal cancer
- MeSH:
Carcinogenesis;
Colorectal Neoplasms*;
Deoxyribonuclease I;
DNA Repair*;
DNA*;
Hominidae;
Humans*;
Incidence;
Introns;
Open Reading Frames;
Point Mutation
- From:Experimental & Molecular Medicine
1997;29(3):165-170
- CountryRepublic of Korea
- Language:English
-
Abstract:
Structural and functional changes in the major apurinic/apyrimidinic DNA endonuclease (APEX) gene in human colorectal cancers were investigated. DNAs were prepared from surgically removed 25 human colorectal tissues and direct sequencing of PCR-amplified APEX gene covering the entire protein coding region was performed. Point mutations in 3 and silent mutations in 3 out of 25 colorectal cancer patients were found. Base substitutions in intron II were also found in 2 patients. T<-> C or some A<-> G transitions were the most typical pattern of the mutations. AP DNA endonuclease (APE) activities in normal and tumor tissues were 65.7 EU/mg and 21.7 EU/mg, respectively. APEX protein was detected in both normal and tumor tissues and no remarkable difference in the amount of APEX protein between colorectal cancer tissues and their normal counterparts was observed. The incidence of APEX gene mutation in colorectal cancer was 12% which is relatively lower than that of other genes associated with colorectal tumor, but a significant reduction of APE enzyme activities in tumor tissues, especially in those with APEX mutations, was observed. These results indicate that the decreased APE enzyme activity might be closely related to the colorectal tumorigenesis, although no quantitative correlation between APE enzyme activity and APEX content exists.
