Serine Protease Inhibitor Kazal Type 1 Promotes Proliferation of Pancreatic Cancer Cells through the Epidermal Growth Factor Receptor
Serine Protease Inhibitor Kazal Type 1 Promotes Proliferation of Pancreatic Cancer Cells through the Epidermal Growth Factor Receptor
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DOI：
10.1158/1541-7786.mcr-08-0567
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发表时间：
2009-09-01
影响因子：
5.2
通讯作者：
Yamamura, Ken-ichi
中科院分区：
文献类型：
--
作者：
Ozaki, Nobuyuki;Ohmuraya, Masaki;Yamamura, Ken-ichi
丝氨酸蛋白酶抑制因子1(SPINK1)不仅在正常胰腺腺泡细胞中表达，而且在多种胰腺导管肿瘤中也有表达。SPINK1和表皮生长因子(EGF)在结构上有相似性。因此，我们假设SPINK1与EGF受体(EGFR)结合，激活其下游信号转导。我们首次发现SPINK1可诱导NIH3T3细胞和胰腺癌细胞系的增殖。我们在免疫沉淀实验中证明了SPINK1与EGFR共沉淀，并用石英晶体微天平(QCM)技术证明了SPINK1与EGFR的结合亲和力约为EGF的一半。正如预期的那样，EGFR及其下游分子、信号转导和转录激活因子3、v-Akt小鼠胸腺瘤病毒癌基因同源物和细胞外信号调节激酶1/2被SPINK1和EGF磷酸化。为了确定哪条途径对细胞生长最重要，我们进一步分析了抑制剂的作用。EGF或SPINK1对细胞生长的刺激作用可被EGFR和丝裂原活化蛋白激酶/细胞外信号调节激酶抑制剂完全抑制，但不能被Janus激活的激酶和磷脂酰肌醇3-激酶抑制剂所抑制。为了进一步分析SPINK1在胰腺癌发生发展中的临床意义，我们检测了SPINK1和EGFR在胰腺管状腺癌和胰腺上皮内肿瘤中的表达。SPNK1和EGFR不仅在早期癌Panin-1A中表达，而且在晚期癌中也有表达。综上所述，这些结果表明，SPINK1通过EGFR/丝裂原激活的蛋白激酶级联反应刺激胰腺癌细胞的增殖。(摩尔癌症研究2009；7(9)：1572-81)
Serine protease inhibitor, Kazal type 1 (SPINK1) is expressed not only in normal human pancreatic acinar cells but also in a variety of pancreatic ductal neoplasms. There are structural similarities between SPINK1 and epidermal growth factor (EGF). Hence, we hypothesized that SPINK1 binds to EGF receptor (EGFR) to activate its downstream signaling. We first showed that SPINK1 induced proliferation of NIH 3T3 cells and pancreatic cancer cell lines. We showed that SPINK1 coprecipitated with EGFR in an immunoprecipitation experiment and that the binding affinity of SPINK1 to EGFR was about half of that of EGF using quartz-crystal microbalance (QCM) technique. As expected, EGFR and its downstream molecules, signal transducer and activator of transcription 3, v-Akt murine thymoma viral oncogene homologue, and extracellular signal-regulated kinase 1/2, were phosphorylated by SPINK1 as well as EGF. To determine which pathway is the most important for cell growth, we further analyzed the effect of inhibitors. Growth stimulation by EGF or SPINK1 was completely inhibited by EGFR and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase inhibitor but not by Janus-activated kinase and phosphoinositide 3-kinase inhibitors. To further analyze the clinical importance of SPINK1 in the development of pancreatic cancer, we examined the expression of SPINK1 and EGFR in pancreatic tubular adenocarcinomas and pancreatic intraepithelial neoplasm. Both SPNK1 and EGFR were coexpressed not only in the early stage of cancer, PanIN-1A, but also in advanced stages. Taken together, these results suggest that SPINK1 stimulates the proliferation of pancreatic cancer cells through the EGFR/mitogen-activated protein kinase cascade. (Mol Cancer Res 2009;7(9):1572-81)