Trifluorothymidine Resistance Is Associated with Decreased Thymidine Kinase and Equilibrative Nucleoside Transporter Expression or Increased Secretory Phospholipase A2
Trifluorothymidine Resistance Is Associated with Decreased Thymidine Kinase and Equilibrative Nucleoside Transporter Expression or Increased Secretory Phospholipase A2
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DOI：
10.1158/1535-7163.mct-09-0932
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发表时间：
2010-04-01
影响因子：
5.7
通讯作者：
Peters, Godefridus J.
中科院分区：
文献类型：
--
作者：
Temmink, Olaf H.;Bijnsdorp, Irene V.;Peters, Godefridus J.
三氟胸苷（TFT）是新型口服制剂TAS-102的一部分，目前正在II期研究中进行评价。耐药性是癌症治疗的一个重要限制。本研究的目的是使用两种不同的方案诱导H630结肠癌细胞对TFT的耐药性，并分析耐药机制。将电池连续或间歇地暴露于TFT，分别产生H630-cTFT和H630- 4 TFT。分析细胞的交叉耐药性、细胞周期、蛋白质表达以及胸苷磷酸化酶（TP）、胸苷激酶（TK）、胸苷酸合成酶（TS）、平衡核苷转运蛋白（hENT）的活性、基因表达（微阵列）和基因组改变。两种细胞系均对2 '-脱氧-5-氟尿苷具有交叉抗性（>170倍）。暴露于IC 75-TFT增加了H630细胞的S/G（2）-M期，而在耐药变体中未观察到变化。两种主要的靶酶TS和TP在两种TFT抗性变体中保持不变。在H630- 4 TFT细胞中，TK蛋白表达和活性降低，导致TFT活性降低，这很可能是TFT耐药的机制。在H630-cTFT细胞中，hENT mRNA表达降低2- 3倍，导致TFT核苷酸蓄积降低5- 10倍。令人惊讶的是，微阵列-mRNA分析显示分泌型磷脂酶-A2（sPLA 2; 47倍）的强烈增加，这也通过逆转录-PCR（RT-PCR; 211倍）发现。sPLA 2抑制部分逆转了TFT电阻。H630-cTFT有许多染色体畸变，但sPLA 2在TFT抗性中的确切作用仍不清楚。总之，对TFT的抗性诱导可导致不同的抗性机制，包括TK蛋白表达和酶活性降低、hENT表达降低以及（磷酸）脂质代谢。Mol Cancer Ther; 9（4）; 1047-57. (C)2010年AACR。
Trifluorothymidine (TFT) is part of the novel oral formulation TAS-102, which is currently evaluated in phase II studies. Drug resistance is an important limitation of cancer therapy. The aim of the present study was to induce resistance to TFT in H630 colon cancer cells using two different schedules and to analyze the resistance mechanism. Cells were exposed either continuously or intermittently to TFT, resulting in H630-cTFT and H630-4TFT, respectively. Cells were analyzed for cross-resistance, cell cycle, protein expression, and activity of thymidine phosphorylase (TP), thymidine kinase (TK), thymidylate synthase (TS), equilibrative nucleoside transporter (hENT), gene expression (microarray), and genomic alterations. Both cell lines were cross-resistant to 2'-deoxy-5-fluorouridine (>170-fold). Exposure to IC75-TFT increased the S/G(2)-M phase of H630 cells, whereas in the resistant variants, no change was observed. The two main target enzymes TS and TP remained unchanged in both TFT-resistant variants. In H630-4TFT cells, TK protein expression and activity were decreased, resulting in less activated TFT and was most likely the mechanism of TFT resistance. In H630-cTFT cells, hENT mRNA expression was decreased 2-to 3-fold, resulting in a 5-to 10-fold decreased TFT-nucleotide accumulation. Surprisingly, microarray-mRNA analysis revealed a strong increase of secretory phospholipase-A2 (sPLA2; 47-fold), which was also found by reverse transcription-PCR (RT-PCR; 211-fold). sPLA2 inhibition reversed TFT resistance partially. H630-cTFT had many chromosomal aberrations, but the exact role of sPLA2 in TFT resistance remains unclear. Altogether, resistance induction to TFT can lead to different mechanisms of resistance, including decreased TK protein expression and enzyme activity, decreased hENT expression, as well as (phospho) lipid metabolism. Mol Cancer Ther; 9(4); 1047-57. (C) 2010 AACR.