Ishitoya Satoshi, Kurazono Hisao, Nishiyama Hiroyuki, Nakamura Eijiro, Kamoto Toshiyuki, Habuchi Tomonori, Terai Akito, Ogawa Osamu, Yamamoto Shingo
Department of Urology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
J Urol. 2004 Mar;171(3):1309-13. doi: 10.1097/01.ju.0000100110.11129.85.
Verotoxins (VTs) are subunit toxins produced by enteropathogenic Escherichia coli. The VT receptor glycolipid Gb3, which mediates the cytotoxicity of VTs, has been reported to be elevated on the surface of several tumor cell lines. In this study the effect of VT1 as an antineoplastic agent was assessed using various human urological cancer cell lines.
The expression of Gb3 on human cancer cell lines originating from renal cell carcinoma (ACHN, A-704, CAKI-1 and CAKI- 2), prostate cancer (LNCaP and PC3) and testicular tumor (2102Ep) were examined by FACScan (Becton Dickinson, Sunnyvale, California). These cell lines were cultured with various concentrations of VT1 and subjected to microculture tetrazolium dye assay for determination of cell viability. Furthermore, ACHN cells were inoculated into the backs of SCID mice and intratumor injection of VT1 was performed. Pathological samples were examined by hematoxylin and eosin staining as well as by TUNEL assay.
The growth of ACHN, CAKI-1, A-704, 2102Ep and LNCaP but not CAKI-2 and PC3 was significantly inhibited by co-incubation with VT1, as determined by microculture tetrazolium dye assays, consistent with FACScan results for Gb3 expression. When mice bearing ACHN tumors were injected with VT1, rapid reduction in the size of subcutaneous tumors was observed with complete regression within 5 to 7 days. Pathological examination by the TUNEL method indicated that the cytotoxicity of VT1 was mediated by apoptosis.
These results suggest that VTs could be candidates for antineoplastic agents against Gb3 expressing tumors for clinical use.
志贺毒素（VTs）是由肠道致病性大肠杆菌产生的亚单位毒素。据报道，介导VTs细胞毒性的VT受体糖脂Gb3在几种肿瘤细胞系表面的表达有所升高。在本研究中，使用多种人类泌尿系统癌细胞系评估了VT1作为抗肿瘤药物的作用。
通过流式细胞仪（Becton Dickinson，加利福尼亚州桑尼维尔）检测源自肾细胞癌（ACHN、A - 704、CAKI - 1和CAKI - 2）、前列腺癌（LNCaP和PC3）以及睾丸肿瘤（2102Ep）的人类癌细胞系上Gb3的表达。这些细胞系用不同浓度的VT1进行培养，并进行微量培养四氮唑染料法以测定细胞活力。此外，将ACHN细胞接种到SCID小鼠的背部，并进行瘤内注射VT1。通过苏木精和伊红染色以及TUNEL分析对病理样本进行检查。
微量培养四氮唑染料法测定结果表明，与VT1共同孵育后，ACHN、CAKI - 1、A - 704、2102Ep和LNCaP细胞的生长受到显著抑制，而CAKI - 2和PC3细胞未受抑制，这与Gb3表达的流式细胞仪检测结果一致。给携带ACHN肿瘤的小鼠注射VT1后，观察到皮下肿瘤大小迅速减小，在5至7天内完全消退。TUNEL法病理检查表明，VT1的细胞毒性是由凋亡介导的。
这些结果表明，VTs可能是临床上用于对抗表达Gb3的肿瘤的抗肿瘤药物候选物。
