Xu B H, Gupta V, Singh S V
Cancer Research Laboratory, Mercy Hospital, Pittsburgh, Pennsylvania 15219.
Arch Biochem Biophys. 1994 Jan;308(1):164-70. doi: 10.1006/abbi.1994.1023.
In this study, we have examined the relationship between sensitivity to mitomycin C (MMC) and glutathione (GSH) and glutathione transferase (GST) levels using a panel of three unrelated human bladder cancer cell lines. J82, HT-1197, and SCaBER. Cell lines HT-1197 and SCaBER were about 2- and 4.5-fold more resistant to MMC as compared to J82. Although the GSH level did not differ significantly in these cell lines, GST activity in HT-1197 and SCaBER cells were higher by about 2.3- and 6.0-fold, respectively, as compared to J82. Similar to GST activity, GST pi content was highest in the most insensitive cell line and lowest in J82 cells. The cytotoxicity of MMC was increased significantly in these cells by a 1-h pretreatment with a nontoxic concentration of ethacrynic acid (EA), an inhibitor of GST activity. EA pretreatment resulted in a marked GSH depletion as well as GST activity inhibition in both of these cells. Although pretreatment of J82 and SCaBER cells with a nontoxic concentration of D,L-buthionine-S,R-sulfoximine (BSO) caused similar GSH depletion, the cytotoxicity of MMC was enhanced only in SCaBER cells. The differential effect of BSO on MMC cytotoxicity in these cell lines appeared to be due to the differences in the extent of GSH regeneration after removal of BSO. While a marked GSH regeneration occurred in J82 cells within 1 h after BSO removal, such an effect was not observed in SCaBER cells. Combined treatment of these cells with BSO and EA produced a greater potentiation of MMC cytotoxicity in both the cell lines when compared to BSO or EA treatment alone. We conclude that GSH/GST levels may affect the sensitivity of human bladder cancer cells to MMC.
在本研究中，我们使用三种不相关的人膀胱癌细胞系J82、HT - 1197和SCaBER，研究了对丝裂霉素C（MMC）的敏感性与谷胱甘肽（GSH）及谷胱甘肽转移酶（GST）水平之间的关系。与J82相比，HT - 1197和SCaBER细胞系对MMC的耐药性分别约高2倍和4.5倍。尽管这些细胞系中的GSH水平没有显著差异，但与J82相比，HT - 1197和SCaBER细胞中的GST活性分别高约2.3倍和6.0倍。与GST活性相似，GST π含量在最不敏感的细胞系中最高，在J82细胞中最低。用无毒浓度的依他尼酸（EA，一种GST活性抑制剂）预处理1小时后，这些细胞中MMC的细胞毒性显著增加。EA预处理导致这两种细胞中GSH明显耗竭以及GST活性受到抑制。尽管用无毒浓度的D，L - 丁硫氨酸 - S，R - 亚砜胺（BSO）预处理J82和SCaBER细胞会导致类似的GSH耗竭，但MMC的细胞毒性仅在SCaBER细胞中增强。BSO对这些细胞系中MMC细胞毒性的不同影响似乎是由于去除BSO后GSH再生程度的差异。在去除BSO后1小时内，J82细胞中发生了明显的GSH再生，而在SCaBER细胞中未观察到这种效应。与单独使用BSO或EA处理相比，将这些细胞与BSO和EA联合处理在两种细胞系中产生了更大的MMC细胞毒性增强作用。我们得出结论，GSH/GST水平可能会影响人膀胱癌细胞对MMC的敏感性。
