Yang Z, Faustino P J, Andrews P A, Monastra R, Rasmussen A A, Ellison C D, Cullen K J
Lombardi Cancer Center, Georgetown University, Washington, DC 20007, USA.
Cancer Chemother Pharmacol. 2000;46(4):255-62. doi: 10.1007/s002800000167.
To evaluate the correlation between cisplatin sensitivity, intracellular glutathione, and platinum/DNA adduct formation (measured by atomic absorption spectroscopy) in a series of seven head and neck cancer cell lines, and to evaluate the effect of biochemical modulation of glutathione on platinum/DNA adduct formation and repair.
Cisplatin/DNA adducts were measured by atomic absorption spectroscopy. Glutathione content was measured by enzymatic assay and was modulated with buthionine sulfoximine. Apoptosis was measured by double-labeled flow cytometry.
Intracellular glutathione concentration was strongly correlated with cisplatin resistance (P = 0.002, R2 = 0.7). There was also a statistically significant inverse correlation between cisplatin/DNA adduct formation and the IC50 for cisplatin in these cell lines. (P = 0.0004, R2 = 0.67). In addition, resistant cells were able to repair approximately 70% of cisplatin/DNA adducts at 24 h, while sensitive cells repaired less than 28% of adducts in the same period. However, despite the positive correlation between cellular glutathione and cisplatin resistance, there was no direct correlation between intracellular glutathione concentration and platinum/DNA adduct formation. Further, depletion of intracellular glutathione by buthionine sulfoximine did not dramatically alter formation of cisplatin/DNA adducts even though it resulted in marked increase in cisplatin cytotoxicity and was associated with increased apoptosis.
These results suggest that glutathione has multiple effects not directly related to formation of cisplatin/DNA adducts, but may also be an important determinant of the cell's ability to repair cisplatin-induced DNA damage and resist apoptosis.
评估一系列七种头颈癌细胞系中顺铂敏感性、细胞内谷胱甘肽与铂/DNA加合物形成（通过原子吸收光谱法测量）之间的相关性，并评估谷胱甘肽的生化调节对铂/DNA加合物形成和修复的影响。
通过原子吸收光谱法测量顺铂/DNA加合物。通过酶促测定法测量谷胱甘肽含量，并用丁硫氨酸亚砜胺进行调节。通过双标记流式细胞术测量细胞凋亡。
细胞内谷胱甘肽浓度与顺铂耐药性密切相关（P = 0.002，R2 = 0.7）。在这些细胞系中，顺铂/DNA加合物形成与顺铂的IC50之间也存在统计学上显著的负相关（P = 0.0004，R2 = 0.67）。此外，耐药细胞在24小时内能够修复约70%的顺铂/DNA加合物，而敏感细胞在同一时期修复的加合物不到28%。然而，尽管细胞内谷胱甘肽与顺铂耐药性呈正相关，但细胞内谷胱甘肽浓度与铂/DNA加合物形成之间没有直接相关性。此外，丁硫氨酸亚砜胺耗尽细胞内谷胱甘肽，即使它导致顺铂细胞毒性显著增加并与细胞凋亡增加相关，但并未显著改变顺铂/DNA加合物的形成。
这些结果表明，谷胱甘肽具有多种与顺铂/DNA加合物形成不直接相关的作用，但也可能是细胞修复顺铂诱导的DNA损伤和抵抗细胞凋亡能力的重要决定因素。
