Chiorean Mihnea V, Guicciardi Maria Eugenia, Yoon Jung-Hwan, Bronk Steven F, Kaufmanns Scott H, Gores Gregory J
Division of Gastroenterology and Hepatology, and Division of Oncology Research, Mayo Clinic College of Medicine, Rochester, MN, USA.
Liver Int. 2004 Dec;24(6):687-95. doi: 10.1111/j.1478-3231.2004.0984.x.
Cholangiocarcinoma is a highly malignant, usually fatal cancer with limited therapeutic options. Receptor tyrosine kinases contribute to the development and progression of this cancer. The relatively selective tyrosine kinase inhibitor imatinib mesylate (STI-571 or Gleevec(R)) has recently been licensed. However, the ability of this drug to inhibit signal transduction and induce apoptosis in human cholangiocarcinoma cells is incompletely studied. Thus, our goal was to examine the ability of STI-571 to induce apoptosis in KMCH-1 cells, a human cholangiocarcinoma cell line.
Apoptosis was assessed morphologically and also biochemically by measuring caspase activity and the mitochondrial membrane potential. STI-571 induced apoptosis and inhibited growth of KMCH-1 cells in a time- and concentration-dependent manner. The induction of apoptosis was accompanied by mitochondrial depolarization followed by a 4.5-fold increase in caspase activation and was abrogated by the pancaspase inhibitor z-VAD(OMe)-fmk. Interestingly, cholangiocarcinoma cells do not express detectable PDGFR, c-Abl or c-Kit, which are protein kinases known to be directly inhibited by STI-571. However, a significant decrease in epidermal growth factor receptor (EGFR) and focal adhesion kinase (FAK) phosphorylation was observed following treatment with STI-571. This decrease in EGFR and FAK phosphorylation was associated with a reduction in Akt activity resulting in loss of Mcl-1, a potent anti-apoptotic Bcl-2 family protein.
These results indicate that STI-571 induces caspase-dependent apoptosis in a human cholangiocarcinoma cell line and suggest that STI-571 might warrant further investigation as a possible agent for treatment of human cholangiocarcinoma.
胆管癌是一种高度恶性、通常致命的癌症，治疗选择有限。受体酪氨酸激酶在这种癌症的发生和发展中起作用。相对选择性的酪氨酸激酶抑制剂甲磺酸伊马替尼（STI-571或格列卫®）最近已获许可。然而，该药物抑制人胆管癌细胞信号转导和诱导凋亡的能力尚未得到充分研究。因此，我们的目标是研究STI-571诱导人胆管癌细胞系KMCH-1细胞凋亡的能力。
通过形态学评估凋亡，并通过测量半胱天冬酶活性和线粒体膜电位进行生化评估。STI-571以时间和浓度依赖性方式诱导KMCH-1细胞凋亡并抑制其生长。凋亡的诱导伴随着线粒体去极化，随后半胱天冬酶激活增加4.5倍，并被泛半胱天冬酶抑制剂z-VAD(OMe)-fmk消除。有趣的是，胆管癌细胞不表达可检测到的血小板衍生生长因子受体（PDGFR）、c-Abl或c-Kit，这些是已知可被STI-571直接抑制的蛋白激酶。然而，用STI-571处理后，观察到表皮生长因子受体（EGFR）和粘着斑激酶（FAK）磷酸化显著降低。EGFR和FAK磷酸化的这种降低与Akt活性降低相关，导致强效抗凋亡Bcl-2家族蛋白Mcl-1丢失。
这些结果表明，STI-571在人胆管癌细胞系中诱导半胱天冬酶依赖性凋亡，并表明STI-571作为治疗人胆管癌的可能药物可能值得进一步研究。
