Urade M, Sugi M, Matsuya T
First Department of Oral and Maxillofacial Surgery, Osaka University Faculty of Dentistry.
Jpn J Cancer Res. 1988 Apr;79(4):491-500. doi: 10.1111/j.1349-7006.1988.tb01618.x.
Bleomycin (BLM)-resistant HeLa cells (HeLa-BLMr), which have been subcultured for more than 150 passages during over 2 years in the presence of 1 micrograms/ml of BLM and stably possess a 20-fold-increased BLM-resistance in vitro, were further characterized. The nude mouse tumors produced by HeLa-BLMr were significantly less sensitive (P less than 0.005-0.01) to BLM administration than those produced by HeLa cells, and the cells primarily cultured from nude mouse tumors of HeLa-BLMr and transplanted serially 5 times in the absence of BLM also exhibited a similar degree of BLM resistance to that of HeLa-BLMr cultured in BLM-containing medium. The BLM-resistance mechanism of HeLa-BLMr was partially analyzed. The cells showed about 40% decreased accumulation and 2-3 times reduced retention of [3H]peplomycin, a novel BLM analog, as compared to HeLa cells, but the BLM-hydrolase activity was at almost the same level as that of HeLa cells when determined by HPLC. Furthermore, alkaline sucrose gradient analysis of cellular DNA after BLM treatment revealed that the damaged DNA was more efficiently repaired in HeLa-BLMr than in HeLa cells. These results suggest that decreased drug accumulation and retention, and elevated DNA repair activity are the main mechanism of BLM resistance in HeLa-BLMr.
博来霉素（BLM）耐药的HeLa细胞（HeLa - BLMr）在含有1微克/毫升BLM的条件下传代培养超过2年，传代次数超过150次，并且在体外稳定具有20倍增强的BLM耐药性，对其进行了进一步特性分析。HeLa - BLMr产生的裸鼠肿瘤对BLM给药的敏感性明显低于HeLa细胞产生的裸鼠肿瘤（P小于0.005 - 0.01），并且从HeLa - BLMr的裸鼠肿瘤中初代培养并在无BLM条件下连续传代5次的细胞，对BLM的耐药程度也与在含BLM培养基中培养的HeLa - BLMr相似。对HeLa - BLMr的BLM耐药机制进行了部分分析。与HeLa细胞相比，这些细胞对新型BLM类似物[3H]培普利霉素的摄取减少约40%，滞留减少2 - 3倍，但通过高效液相色谱法测定时，BLM水解酶活性与HeLa细胞几乎处于同一水平。此外，BLM处理后细胞DNA的碱性蔗糖梯度分析表明，HeLa - BLMr中受损DNA的修复效率高于HeLa细胞。这些结果表明，药物摄取和滞留减少以及DNA修复活性升高是HeLa - BLMr中BLM耐药的主要机制。
