Bruzzese Francesca, Di Gennaro Elena, Avallone Antonio, Pepe Stefano, Arra Claudio, Caraglia Michele, Tagliaferri Pierosandro, Budillon Alfredo
Experimental Pharmacology Unit, Department of Experimental Oncology, National Cancer Institute G. Pascale, via M. Semmola, 80131 Naples, Italy.
Clin Cancer Res. 2006 Jan 15;12(2):617-25. doi: 10.1158/1078-0432.CCR-05-1671.
Epidermal growth factor receptor (EGFR) overexpression has been implicated in the development of head and neck squamous cell carcinomas (HNSCC) and represents a potential therapeutic target for this disease. We have reported previously that growth inhibitory concentrations of IFN-alpha enhance the expression and activity of EGFR and that this effect could represent an escape mechanism to the growth inhibition and apoptotic cell death induced by IFN-alpha. In this study, we investigate whether the combination of IFN-alpha and gefitinib (Iressa, AstraZeneca Pharmaceuticals, Macclesfield, United Kingdom), a selective EGFR tyrosine kinase inhibitor, might have a cooperative antitumor effect on HNSCC-derived cell lines.
The interaction of IFN-alpha and gefitinib was evaluated in vitro on HNSCC-derived cell lines by median drug effect analysis calculating a combination index with CalcuSyn software and in vivo by using HNSCC xenografts in nude mice. The mechanism of gefitinib and IFN-alpha interactions was also studied by analysis of cell cycle kinetics, apoptosis assays, and Western blotting of EGFR signal transduction components.
Simultaneous exposure to gefitinib and IFN-alpha produced synergistic antiproliferative and proapoptotic effects compared with single drug treatment. Furthermore, daily treatment of gefitinib (50 mg/kg p.o.) in combination with an IFN-alpha regimen (50,000 units s.c. three times weekly) induced tumor growth delay and increased survival rate on established HNSCC xenografts in nude mice. Moreover, the concomitant treatment with gefitinib suppressed the stimulation of extracellular signal-regulated kinase phosphorylation/activity induced by IFN-alpha both in vitro and in vivo.
The observed cooperative antitumor effects could be, at least in part, explained by the inhibition exerted by gefitinib of an IFN-alpha-induced EGF-dependent survival pathway, which involves extracellular signal-regulated kinase activation. These results provide a rationale for the clinical evaluation of gefitinib in combination with IFN-alpha in HNSCC.
表皮生长因子受体（EGFR）的过表达与头颈部鳞状细胞癌（HNSCC）的发生发展有关，是该疾病潜在的治疗靶点。我们之前报道过，干扰素α（IFN-α）的生长抑制浓度会增强EGFR的表达和活性，这种效应可能是IFN-α诱导生长抑制和凋亡性细胞死亡的逃逸机制。在本研究中，我们探究IFN-α与吉非替尼（易瑞沙，阿斯利康制药公司，英国麦克尔斯菲尔德）（一种选择性EGFR酪氨酸激酶抑制剂）联合使用是否对HNSCC来源的细胞系具有协同抗肿瘤作用。
通过使用CalcuSyn软件计算联合指数，在体外对HNSCC来源的细胞系进行中位药物效应分析，评估IFN-α与吉非替尼的相互作用，并在体内使用裸鼠中的HNSCC异种移植瘤进行评估。还通过分析细胞周期动力学、凋亡检测以及EGFR信号转导成分的蛋白质印迹法研究了吉非替尼与IFN-α相互作用的机制。
与单药治疗相比，同时暴露于吉非替尼和IFN-α产生了协同的抗增殖和促凋亡作用。此外，每日给予吉非替尼（口服50 mg/kg）联合IFN-α方案（皮下注射50,000单位，每周三次）可诱导裸鼠中已建立的HNSCC异种移植瘤的肿瘤生长延迟并提高存活率。此外，吉非替尼的联合治疗在体外和体内均抑制了IFN-α诱导的细胞外信号调节激酶磷酸化/活性的刺激。
观察到的协同抗肿瘤作用至少部分可以通过吉非替尼对IFN-α诱导的表皮生长因子（EGF）依赖性存活途径的抑制来解释，该途径涉及细胞外信号调节激酶的激活。这些结果为在HNSCC中对吉非替尼与IFN-α联合使用进行临床评估提供了理论依据。
