Studies on genetic and microbiologicail quality of human tumor xenografts lines as a tool for animal experiments

背景：人肿瘤异种移植(HTXs)是动物实验的有用工具，特别是在抗肿瘤新药的评价中。我们一直在建立HTX，并开发了用于新药评估的肿瘤化疗敏感性面板。目的：在质量控制方面(小鼠类型肿瘤的通道问题和/或肿瘤系之间的人为交叉污染)，我们研究了遗传图谱，以及长期传代对肿瘤生长和化疗敏感性等特性的影响，并讨论了HTX的低温保存储备和定期替换的使用，以保持实验结果的重复性。方法：用同工酶标记和DNA指纹图谱分别鉴定肿瘤的种类和个性。用不同代次的HTX在裸鼠体内测定生长曲线和对抗癌药物的敏感性。结果：在我们保留的肿瘤中，发现5例人类肿瘤从其同工酶标记改变为鼠源性，并被排除在外。我们通过DNA指纹图谱鉴定了我们用于化疗敏感板的肿瘤的个性，并且它们的性质是稳定的，可以在裸鼠体内长期传代。然而，随着传代时间的延长，细胞的生长速度和对药物的敏感性发生了改变，尽管DNA指纹分析没有显示出任何明显的传代变化。结论：同工酶标记和DNA指纹图谱等遗传图谱技术有助于鉴别实验性HTX的个体特征，当肿瘤用于要求实验结果连续重复性的实验时，即使没有人工污染的迹象，也应定期更新。

Background : Human tumor xenografts (HTXs) are a useful tool for animal experiments especially for evaluation of new antitumor drugs. We have been establishing HTXs, and have developed tumor chemosensitivity panels for new drug evaluation using them.Purpose : With regard to quality control (problems in chanes into mouse type tumors and/or artificial cross-contamination among tumor lines), we studied genetic profiling, and effects of long-term passaging on tumor properties such as growth and chemosensitivities, and we discuss the use of cryopreservation stock of HTXs and periodic replacement in order to maintain reproducibility of the experimental results. Methods : We examined isozyme markers and DNA fingerprinting to identify species and individuality of the tumors, respectively. Growth curves and sensitivities to antitumor drugs were examined using HTXs with different passaging in nude mice. Results : Among the tumors we maintained, five human tumors were found to have changed to mouse origin from their isozyme markers and were excluded. We identified the individuality of tumors which we used for the chemosensitivity panels by DNA fingerprinting, and their properties were stable for long-term passaging in nude mice. However, growth speed and chemosensitivities to drugs were altered with long-term passaging, although DNA fingerprint analysis did not show any obvious changes with passaging. Conclusions : Genetic profiling, such as isozyme markers and DNA fingerprinting, is useful for identify individuality of experimental HTXs, and tumors should be renewed periodically even when there are no signs of artificial contamination when they are used in experiments which require continuous reproducibility of experimental results.