DNA damage and repair gene N-methylpurine DNA glycosylase expression in human osteosarcoma
- VernacularTitle:DNA损伤修复基因MPG在人体骨肉瘤的表达及其治疗意义
- Author:
Dong WANG
- Publication Type:Journal Article
- Keywords:
bone tumor;
N-methylpurine DNA glycosylase;
chemosensitivity
- From:Journal of Third Military Medical University
2003;0(17):-
- CountryChina
- Language:Chinese
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Abstract:
Objective To determine N-methylpurine DNA glycosylase (MPG) expression in human osteosarcoma and analyze its association with clinicopathology and prognosis, to construct adenoviral vector of MPG and study its ability to sensitize human osteosarcoma cell HOS to DNA damage agents. Methods The MPG expression was determined by immunohistochemical staining in 60 specimens and 3 cell lines (HOS, SAOS-2, U2OS) of human osteosarcoma. High expression group and low expression group were divided according to their staining intensity, and their association with clinicopathological data and prognosis was analyzed statistically with SAS software. The adenoviral infection and MPG expression, as well as enzyme activity were determined by flow cytometry, Western blotting, and HEX labeled oligonucleotide-based assay respectively. The cell survival/proliferation was measured using MTS, SRB, and thymidine incorporation assay. Apoptotic cells were assayed by flow cytometry after treated with phycoerythin (PE)-conjugated Annexin V and 7-amino-actinomycin (7-AAD). Results The high expression of MPG was found in 40 cases (67%), while low expression in three cell lines of osteosarcoma. MPG expression was significantly associated with WHO histological classification and prognosis by single factor regression analysis. The recombinant adenovirus of 10 MOI was found to infect more than 90% of HOS cells within 24 h by EGFP fluorescence, in which the MPG overexpression and MPG enzyme activity were also detected. The HOS cells with MPG overexpression were more sensitive to the DNA damage agents including MMS, MNNG, and TMZ, and the IC_(50) of three DNA damage agents decreased by 6.0, 4.5, and 2.5 fold respectively. Conclusion Transient MPG overexpression is a potential therapeutic approach for increasing HOS cellular sensitivity to DNA damage agent in chemotherapy.
