Awasthi Y C, Singh S V, Ahmad H, Moller P C, Gupta V
Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston 77550.
Carcinogenesis. 1988 Jan;9(1):89-93. doi: 10.1093/carcin/9.1.89.
A glutathione S-transferase (GST) isoenzyme having common antigenicity to rat placental form (GST-P) and human placental form (GST-pi) has recently been suggested may be a marker of carcinogenesis. In the present study we have investigated the expression of this isoenzyme in three small cell lung cancer cell lines in order to determine whether or not this isoenzyme can be used as a general marker of carcinogenesis. GST activity towards 1-chloro-2,4-dinitrobenzene in two of the cell lines (NES and NOC-361) was moderately higher than that in normal human lung, but this activity was markedly suppressed in one of the cell lines (NCI-H69). Quantitation of the GST isoenzymes in the tumors grown in nude mice by injecting these cell lines also revealed a moderate increase of GST-pi-type isoenzyme in NES and NOC-361 and its suppression in NCI-H69. Immunocytochemical localization studies with these tumors using antibodies raised against GST-pi also indicated a drastic decrease of GST-pi-type isoenzyme in NCI-H69 and this finding was confirmed by Western blot studies. These results suggest that GST-pi, or the isoenzyme(s) having similar immunological nature to GST-pi, cannot be used as the general markers of neoplastic states.
最近有人提出，一种与大鼠胎盘型谷胱甘肽S-转移酶（GST）（GST-P）和人胎盘型谷胱甘肽S-转移酶（GST-π）具有共同抗原性的GST同工酶可能是致癌作用的标志物。在本研究中，我们研究了这种同工酶在三种小细胞肺癌细胞系中的表达情况，以确定该同工酶是否可作为致癌作用的通用标志物。两种细胞系（NES和NOC-361）中针对1-氯-2,4-二硝基苯的GST活性略高于正常人肺组织中的活性，但在其中一种细胞系（NCI-H69）中该活性明显受到抑制。通过注射这些细胞系来定量裸鼠体内生长的肿瘤中的GST同工酶，结果还显示NES和NOC-361中GST-π型同工酶适度增加，而在NCI-H69中受到抑制。使用针对GST-π产生的抗体对这些肿瘤进行免疫细胞化学定位研究也表明，NCI-H69中GST-π型同工酶急剧减少，这一发现通过蛋白质印迹研究得到了证实。这些结果表明，GST-π或与GST-π具有相似免疫性质的同工酶不能用作肿瘤状态的通用标志物。
