Kitazaki Takeshi, Soda Hiroshi, Doi Seiji, Nakano Hirohumi, Nakamura Yoichi, Kohno Shigeru
Second Department of Internal Medicine, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan.
Lung Cancer. 2005 Oct;50(1):19-24. doi: 10.1016/j.lungcan.2005.05.005.
Gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is an active agent in non-small cell lung cancer, and rapidly relieves bronchorrhea in patients with bronchioloalveolar carcinoma before the improvement of radiological findings. In addition, epidermal growth factor regulates mucin secretion in normal airway goblet cells. The present study was designed to clarify whether gefitinib modifies mucin production in lung cancer cell lines apart from its anti-proliferative effects, using A549 adenocarcinoma and NCI-H292 mucoepidermoid carcinoma cells expressing EGFR and MUC5AC mRNA. Mucin synthesis was measured by RT-PCR and ELISA, and MAPK and Akt, the downstream targets of EGFR, were examined by Western blotting assay. The clinically-achievable concentration of 1muM gefitinib inhibited the growth of both cells by only 10%, but gefitinib suppressed MUC5AC mRNA levels subsequent to a decrease in intracellular and secreted MUC5AC protein. Gefitinib also inhibited the phosphorylation of MAPK and Akt, and the selective inhibitors PD98059 and LY294002 also suppressed MUC5AC protein synthesis. These findings suggest that gefitinib may inhibits MUC5AC synthesis, at least in part, through MAPK and Akt signaling pathways. Thus, gefitinib inhibits mucin production, which is encouraging for trials involving its use against bronchorrhea in patients with lung cancer.
吉非替尼是一种表皮生长因子受体（EGFR）酪氨酸激酶抑制剂，是治疗非小细胞肺癌的一种活性药物，可在影像学表现改善之前迅速缓解细支气管肺泡癌患者的支气管溢液。此外，表皮生长因子可调节正常气道杯状细胞中的黏蛋白分泌。本研究旨在使用表达EGFR和MUC5AC mRNA的A549腺癌和NCI-H292黏液表皮样癌细胞，阐明吉非替尼除了其抗增殖作用外，是否还能改变肺癌细胞系中的黏蛋白产生。通过逆转录聚合酶链反应（RT-PCR）和酶联免疫吸附测定（ELISA）测量黏蛋白合成，并通过蛋白质免疫印迹法检测EGFR的下游靶点丝裂原活化蛋白激酶（MAPK）和蛋白激酶B（Akt）。临床可达到的1μM吉非替尼浓度仅使两种细胞的生长抑制了10%，但吉非替尼在细胞内和分泌的MUC5AC蛋白减少后，抑制了MUC5AC mRNA水平。吉非替尼还抑制了MAPK和Akt的磷酸化，选择性抑制剂PD98059和LY294002也抑制了MUC5AC蛋白的合成。这些发现表明，吉非替尼可能至少部分通过MAPK和Akt信号通路抑制MUC5AC的合成。因此，吉非替尼抑制黏蛋白产生，这对于涉及将其用于治疗肺癌患者支气管溢液的试验来说是令人鼓舞的。
