Cai JM, Zheng XL, Luo C, Gao JG, Cheng TM. Characteristics of DNA repair induced by DNA polymerase β in hepatoma cells after γ-ray irradiation.
World J Gastroenterol 1997;
3:75-7. [PMID:
27041944 PMCID:
PMC4801929 DOI:
10.3748/wjg.v3.i2.75]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/1996] [Revised: 01/31/1997] [Accepted: 03/01/1997] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effects of DNA repair induced by DNA polymerase β in hepatoma cells after γ-ray irradiation.
METHODS: Cell nuclei were prepared from mouse model (SMMC LTNM), in which human hepatoma cells are transplanted on nude mice. The nuclei were then irradiated with 60Co-γ rays at different dose levels or dose rates. A selective inhibitor test was then used to detect the effects of the radiation on DNA repair using N-ethylmaleimide (NEM) and ddTTP as selective inhibitors to DNA polymerases γ and β respectively.
RESULTS: 3H-TTP incorporation into irradiated nuclei or calf thymus DNA was significantly higher than that the rate at which it is incorporated into non-irradiated nuclei when either DNA polymerase β or γ was inhibited. When both NEM and ddTTP are present, the 3H-TTP incorporation in irradiated DNA was not significantly different from the non-irradiated nuclei. Furthermore, 3H-TTP incorporation into DNA of SMMC-LTNM hepatoma nuclei was higher than that of normal hepatocyte nuclei (P < 0.01). This suggests that DNA repair induced by DNA polymerase β was more active in hepatoma cell nuclei than in normal hepatocyte nuclei.
CONCLUSION: DNA polymerase β may be more responsive to DNA damage in some tumor cells than that in normal cells, which may facilitate the cells to repair DNA damages from radiation more efficiently.
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