DCK is frequently inactivated in acquired gemcitabine-resistant human cancer cells
DCK is frequently inactivated in acquired gemcitabine-resistant human cancer cells
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DOI：
10.1016/j.bbrc.2012.03.122
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发表时间：
2012-04-27
影响因子：
3.1
通讯作者：
Horii, Akira
中科院分区：
文献类型：
--
作者：
Saiki, Yuriko;Yoshino, Yuki;Horii, Akira
虽然吉西他滨是治疗胰腺癌最有效的化疗药物，但越来越多的患者会产生吉西他滨耐药性。为了阐明获得吉西他滨耐药的机制，我们从六种人类癌细胞系中开发了吉西他滨耐药细胞系;三种胰腺癌，一种胃癌，一种结肠癌和一种胆管癌。我们首先使用三个配对的亲本和吉西他滨耐药胰腺癌细胞系（PK-1和RPK-1、PK-9和RPK-9）分析吉西他滨摄取。PK-59和RPK-59），并发现吉西他滨的摄取迅速。然而，在抗性细胞中没有诱导DNA损伤。我们进一步检查了基于微阵列的细胞表达谱，以确定与吉西他滨耐药相关的基因，并发现脱氧胞苷激酶（DCK）的表达显着减少。DCK是通过磷酸化激活吉西他滨的关键酶。在这些配对的亲本和衍生的吉西他滨耐药细胞系中研究了DCK的遗传改变和表达，仅在吉西他滨耐药细胞系中发现了失活突变。此外，siRNA介导的DCK敲低在亲本细胞系中产生吉西他滨抗性，并且将DCK引入吉西他滨抗性细胞系总是恢复吉西他滨敏感性。将突变分析扩展到三种其他不同的配对细胞系，DLD-1和RDLD-1（结肠癌细胞系）、MKN-28和RMKN-28（胃癌细胞系）以及TFK-1和RTFK-1（胆管癌细胞系）。我们在RMKN-28中发现RDLD-1和RTFK-1的失活突变和DCK表达降低。这些结果表明，DCK的失活是吉西他滨耐药获得的关键机制之一。(C)2012 Elsevier Inc. All rights reserved.
Although gemcitabine is the most effective chemotherapeutic agent against pancreatic cancer, a growing concern is that a substantial number of patients acquire gemcitabine chemoresistance. To elucidate the mechanisms of acquisition of gemcitabine resistance, we developed gemcitabine-resistant cell lines from six human cancer cell lines; three pancreatic, one gastric, one colon, and one bile duct cancer. We first analyzed gemcitabine uptake using three paired parental and gemcitabine resistant pancreatic cancer cell lines (PK-1 and RPK-1, PK-9 and RPK-9. PK-59 and RPK-59) and found that uptake of gemcitabine was rapid. However, no DNA damage was induced in resistant cells. We further examined the microarray-based expression profiles of the cells to identify genes associated with gemcitabine resistance and found a remarkable reduction in the expression of deoxycytidine kinase (DCK). DCK is a key enzyme that activates gemcitabine by phosphorylation. Genetic alterations and expression of DCK were studied in these paired parental and derived gemcitabine-resistant cell lines, and inactivating mutations were found only in gemcitabine-resistant cell lines. Furthermore, siRNA-mediated knockdown of DCK in the parental cell lines yielded gemcitabine resistance, and introduction of DCK into gemcitabine-resistant cell lines invariably restored gemcitabine sensitivities. Mutation analyses were expanded to three other different paired cell lines, DLD-1 and RDLD-1 (colon cancer cell line), MKN-28 and RMKN-28 (gastric cancer cell line), and TFK-1 and RTFK -1 (cholangiocarcinoma cell line). We found inactivating mutations in RDLD-1 and RTFK-1 and decreased expression of DCK in RMKN-28. These results indicate that the inactivation of DCK is one of the crucial mechanisms in acquisition of gemcitabine resistance. (C) 2012 Elsevier Inc. All rights reserved.