Battelli M G, Bolognesi A, Olivieri F, Polito L, Stirpe F
Department of Experimental Pathology, University of Bologna, Italy.
J Drug Target. 1998;5(3):181-91. doi: 10.3109/10611869808995873.
The in vitro sensitivity of cells to a Ber-H2(anti-CD30)/saporin-S6 immunotoxin has been investigated. The CD30+ cell lines, K562, L428 and L540, were used to study cell binding, uptake and degradation of the immunotoxin. K562 cells were less sensitive than L428 and L540 cells to the immunotoxin by approximately one order of magnitude. The difference in cytotoxicity correlated with the intracellular accumulation and with the ratio of degraded over total internalized Ber-H2/saporin-S6, regardless of the immunotoxin binding to the cells. After 6 h incubation, the less sensitive K562 cells (i) accumulated only one third and one tenth of the immunotoxin accumulated by the more sensitive L428 and L540 cells, respectively, and (ii) degraded two thirds of the internalized protein versus one third degraded by either L428 or L540 cells. Ammonium chloride and chloroquine reduced the cytotoxicity of the immunotoxin towards K562 but not to L540 cells. This effect correlated with the increment of immunotoxin catabolism by K562 cells in the presence of chloroquine. In conclusion, uptake alone of an immunotoxin by target cells is not sufficient to assure its efficacy which might also depend on intracellular routing. Only a cytotoxicity test may be really predictive.
已经研究了细胞对Ber-H2（抗CD30）/皂草毒素-S6免疫毒素的体外敏感性。使用CD30 +细胞系K562、L428和L540来研究免疫毒素的细胞结合、摄取和降解。K562细胞对免疫毒素的敏感性比L428和L540细胞低约一个数量级。细胞毒性的差异与细胞内积累以及降解的与内化的总Ber-H2/皂草毒素-S6的比例相关，而与免疫毒素与细胞的结合无关。孵育6小时后，敏感性较低的K562细胞（i）分别仅积累了敏感性较高的L428和L540细胞积累的免疫毒素的三分之一和十分之一，并且（ii）降解了内化蛋白的三分之二，而L428或L540细胞降解了三分之一。氯化铵和氯喹降低了免疫毒素对K562细胞的细胞毒性，但对L540细胞没有影响。这种作用与氯喹存在下K562细胞免疫毒素分解代谢的增加相关。总之，靶细胞仅摄取免疫毒素不足以确保其疗效，疗效可能还取决于细胞内途径。只有细胞毒性试验可能具有真正的预测性。
