Thioredoxin is downstream of Smad7 in a pathway that promotes growth and suppresses cisplatin-induced apoptosis in pancreatic cancer
Thioredoxin is downstream of Smad7 in a pathway that promotes growth and suppresses cisplatin-induced apoptosis in pancreatic cancer
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DOI：
10.1158/0008-5472.can-03-2999
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发表时间：
2004-05-15
期刊：
影响因子：
11.2
通讯作者：
Korc, M
中科院分区：
文献类型：
--
作者：
Arnold, NB;Ketterer, K;Korc, M
胰腺导管腺癌（PDAC）是一种侵袭性人类恶性肿瘤，其中Smad 7通常过表达。通过差异显示的分析鉴定了硫氧还蛋白-1（TRX）作为一种基因，其基础表达在经工程改造以过表达Smad 7的科洛-357胰腺癌细胞中增加。为了描述TRX过表达的生物学后果，我们评估了PDAC中的TRX mRNA水平，并研究了Smad 7过表达细胞中TRX水平增加的影响。通过北方印迹法，与正常胰腺相比，PDAC样品中TRX mRNA水平增加。此外，对激光捕获的胰腺癌细胞的分析显示Smad 7和TRX mRNA水平平行增加。逆转录病毒感染的反义TRX cDNA抑制TRX蛋白水平和钝化Smad 7过表达细胞在软琼脂中形成集落的能力增加。TRX抑制剂1-甲基-丙基-2-咪唑啉基二硫化物（1-Methyl-propyl-2-imidazolozyl disulfide，1-methyl-propyl-2-imidazolozyl disulfide，1-methyl-propyl-2-imidazolozyl disulfide）显著抑制假转染的科洛-357细胞的生长，并增强顺铂（cis-diaminedichloropatinum（II），CDDP）的生长抑制作用。CDDP还诱导细胞凋亡，如通过诱导DNA梯状化、PARP裂解和半胱天冬酶-3/9活性所证明的。这些促凋亡作用在Smad 7过表达细胞中大大减弱，这表现出TRX与凋亡诱导剂凋亡信号调节激酶-1的更长时间的关联，并增强了对CDDP的核因子κ B活化。这些研究结果表明，TRX是Smad 7的下游途径，赋予胰腺癌细胞的生长优势，并增加其对CDDP介导的细胞凋亡的抵抗力，这意味着Smad 7的新的调节功能。
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive human malignancy in which Smad7 is commonly overexpressed. Analysis by differential display identified thioredoxin-1 (TRX) as a gene whose basal expression is increased in COLO-357 pancreatic cancer cells engineered to overexpress Smad7. To delineate the biological consequences of TRX overexpression, we assessed TRX mRNA levels in PDAC and studied the effects of increased TRX levels in Smad7-overexpressing cells. By northern blotting, TRX mRNA levels were increased in PDAC samples by comparison with the normal pancreas. Moreover, analysis of laser-captured pancreatic cancer cells revealed parallel increases in Smad7 and TRX mRNA levels. Retroviral infection of an antisense TRX cDNA suppressed TRX protein levels and blunted the increased capacity of Smad7-overexpressing cells to form colonies in soft agar. 1-Methyl-propyl-2-imidazolozyl disulfide, a TRX inhibitor, markedly suppressed the growth of sham-transfected COLO-357 cells and enhanced the growth inhibitory actions of cis-diamminedichloroplatinum(II) (CDDP). CDDP also induced apoptosis, as evidenced by induction of DNA laddering, PARP cleavage, and caspase-3/9 activities. These pro-apoptotic actions were greatly attenuated in Smad7-overexpressing cells, which exhibited a more prolonged association of TRX with the apoptosis inducer apoptosis signal-regulating kinase-1, and enhanced nuclear factor kappaB activation in response to CDDP. These findings suggest that TRX is downstream of Smad7 in a pathway that confers a growth advantage to pancreatic cancer cells and that increases their resistance to CDDP-mediated apoptosis, implying novel regulatory functions for Smad7.