Department of Oncology, Lund University, Lund, Sweden.
Anticancer Drugs. 2010 Jun;21(5):523-31. doi: 10.1097/CAD.0b013e328337b867.
Preclinical studies have indicated that there is only partial cross-resistance between cisplatin and oxaliplatin. The molecular background for this is incompletely known. To investigate the differences in resistance, we rendered a colon cancer cell line (S1) resistant against cisplatin and oxaliplatin and characterized the subclones with regard to cross-resistance, platinum uptake, and gene expression profiles. Four oxaliplatin and four cisplatin-resistant cell lines were produced from S1 by step-wise increasing the concentrations of the drugs in the growth medium. Cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and platinum accumulation in cell lysates and DNA preparations by inductively coupled plasma mass spectroscopy. Gene expression was investigated by cDNA microarrays. The protein expression of the ATP-binding cassette B1 (ABCB1) was measured by immunohistochemistry. The cisplatin-resistant cell lines were 1.5-6.2-fold resistant against cisplatin and the oxaliplatin-resistant sublines 2.6-17-fold resistant against oxaliplatin. There was a limited degree of cross-resistance. Oxaliplatin resistance could be explained to a larger degree by reduced drug accumulation whereas mechanisms for increased tolerance against platinum incorporation in DNA seemed to be of higher importance for resistance against cisplatin. A greater number of ABC transporters were upregulated in the oxaliplatin-resistant cell lines compared with those selected for cisplatin resistance. ABCB1 was highly overexpressed in the three most oxaliplatin-resistant sublines, but significantly underexpressed in the two most cisplatin-resistant cell lines. This was also confirmed by immunohistochemistry. However, functional tests did not show any increase in ABCB1 transport activity in the oxaliplatin-resistant sub-lines compared with S1.
临床前研究表明，顺铂和奥沙利铂之间只有部分交叉耐药性。其分子基础尚不完全清楚。为了研究耐药性的差异，我们使结肠癌细胞系（S1）对顺铂和奥沙利铂产生耐药性，并对亚克隆进行了交叉耐药性、铂摄取和基因表达谱的特征分析。通过逐步增加生长培养基中药物的浓度，从 S1 中产生了 4 株奥沙利铂耐药细胞系和 4 株顺铂耐药细胞系。通过 3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四唑溴盐（MTT）测定法和电感耦合等离子体质谱法测定细胞裂解物和 DNA 制剂中的铂积累来确定细胞毒性。通过 cDNA 微阵列研究基因表达。通过免疫组织化学法测量 ATP 结合盒 B1（ABCB1）的蛋白表达。顺铂耐药细胞系对顺铂的耐药性为 1.5-6.2 倍，奥沙利铂耐药亚系对奥沙利铂的耐药性为 2.6-17 倍。交叉耐药性程度有限。奥沙利铂耐药性在更大程度上可以通过减少药物积累来解释，而对于增加耐受铂在 DNA 中结合的机制对于抵抗顺铂似乎更为重要。与选择顺铂耐药的细胞系相比，奥沙利铂耐药细胞系中上调的 ABC 转运蛋白数量更多。ABCB1 在三个最耐奥沙利铂的亚系中高度过表达，但在两个最耐顺铂的细胞系中表达显著下调。免疫组织化学也证实了这一点。然而，功能测试并未显示奥沙利铂耐药亚系与 S1 相比，ABCB1 转运活性增加。
