肝癌细胞辐射敏感性与G_2期染色体畸变的线性关系及其应用研究

The linear correlation between human hepatoma cellular radiosensitivity and G_2-chromosome aberration measured by the G_2-PCC assay

目的研究人肝癌细胞系HepG2细胞辐射敏感性与G2期染色体断裂畸变关系及临床应用的可行性。方法用Calyculin-A诱导的早熟染色体凝集技术测定细胞G2期染色体断裂畸变,用克隆形成实验测定细胞受照后的克隆形成率。结果γ射线照射24h后,G2期细胞内残存的等点染色单体断裂和染色单体型断裂与剂量之间存在良好的相关性;两类畸变与受照后的细胞存活分数均有一定的相关性,但等点染色单体断裂畸变的相关性(r为0·989)比染色单体型的(r为0·853)强。结论细胞照后24h,残存G2等点染色单体断裂畸变可以作为预测HepG2细胞内在辐射敏感性的指标,也可为临床诊断和治疗肝癌提供依据。

Objective To investigate the correlation between G2-chromsome aberrations induced by γ- rays and intrinsic radiosensitivity and to see whether the result can be used to predict the cellular radiosensitivity. Methods HepG2 cells were irradiated with a range of doses and assessed both for cell survival and for residual G2-chromsome aberrations at 24 h after irradiation. The cell survival fraction was described by colony assay; the residual G2-chromsome aberrations including iso-chromatid breaks and chromatid-type breaks were detected by Calyculin-A induced premature chromosome condensation technique at 24 h after irradiation. Results The cell survival fraction decreased with the dose in linearly quadratic manner; the residual G2 iso-chromatid breaks per cell and G2 chromatid-type breaks per cell after 24 h of post-irradiation linearly increased with the dose. There is an inverse relationship between intrinsic radiosensitivity and G2 iso-chromatid breaks per cell （ - 0.989） or G2 chromatid-type breaks per cell （ -0.853 ）. Conclusions The residual G2 iso-chromatid breaks after 24 h of post-irradiation can represent the cell intrinsic radiosensitivity.