Head and Neck Cancer Research Team, Cancer Research Malaysia, No. 1, Jalan SS12/1A, 47500, Subang Jaya, Selangor, Malaysia.
Department of Oral and Maxillofacial Clinical Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia.
Target Oncol. 2019 Apr;14(2):223-235. doi: 10.1007/s11523-019-00626-8.
Given that aberrant activation of epidermal growth factor receptor family receptors (ErbB) is a common event in oral squamous cell carcinoma, and that high expression of these receptor proteins is often associated with poor prognosis, this rationalizes the approach of targeting ErbB signaling pathways to improve the survival of patients with oral squamous cell carcinoma. However, monotherapy with the ErbB blocker afatinib has shown limited survival benefits.
This study was performed to identify mechanisms of afatinib resistance and to explore potential afatinib-based combination treatments with other targeted inhibitors in oral squamous cell carcinoma.
We determined the anti-proliferative effects of afatinib on a panel of oral squamous cell carcinoma cell lines using a crystal violet-growth inhibition assay, click-iT 5-ethynyl-2'-deoxyuridine staining, and cell-cycle analysis. Biochemical assays were performed to study the underlying mechanism of drug treatment as a single agent or in combination with the MEK inhibitor trametinib. We further evaluated and compared the anti-tumor effects of single agent and combined treatment by using oral squamous cell carcinoma xenograft models.
In this study, we showed that afatinib inhibited oral squamous cell carcinoma cell proliferation via cell-cycle arrest at the G/G phase, and inhibited tumor growth in xenograft mouse models. Interestingly, we demonstrated reactivation of the mitogen-activated protein kinase (ERK1/2) pathway in vitro, which possibly reduced the effects of ErbB inhibition. Concomitant treatment of oral squamous cell carcinoma cells with afatinib and trametinib synergized the anti-tumor effects in oral squamous cell carcinoma-bearing mouse models.
Our findings provide insight into the molecular mechanism of resistance to afatinib and support further clinical evaluation into the combination of afatinib and MEK inhibition in the treatment of oral squamous cell carcinoma.
由于表皮生长因子受体家族受体（ErbB）的异常激活是口腔鳞状细胞癌的常见事件，并且这些受体蛋白的高表达通常与预后不良相关，因此，靶向 ErbB 信号通路以改善口腔鳞状细胞癌患者的生存率是合理的。然而，ErbB 阻滞剂阿法替尼的单一疗法显示出有限的生存获益。
本研究旨在确定阿法替尼耐药的机制，并探索在口腔鳞状细胞癌中使用其他靶向抑制剂与阿法替尼联合治疗的潜在方案。
我们使用结晶紫生长抑制测定法、click-iT 5-乙炔基-2'-脱氧尿苷染色和细胞周期分析来确定阿法替尼对一系列口腔鳞状细胞癌细胞系的抗增殖作用。进行生化测定以研究作为单一药物或与 MEK 抑制剂曲美替尼联合治疗的潜在机制。我们进一步通过口腔鳞状细胞癌异种移植模型评估和比较了单一药物和联合治疗的抗肿瘤效果。
在这项研究中，我们表明阿法替尼通过细胞周期阻滞在 G1/G0 期抑制口腔鳞状细胞癌细胞的增殖，并抑制异种移植小鼠模型中的肿瘤生长。有趣的是，我们在体外证明了丝裂原活化蛋白激酶（ERK1/2）途径的重新激活，这可能降低了 ErbB 抑制的效果。阿法替尼和曲美替尼联合治疗口腔鳞状细胞癌细胞协同增强了口腔鳞状细胞癌荷瘤小鼠模型中的抗肿瘤效果。
我们的研究结果提供了对阿法替尼耐药的分子机制的深入了解，并支持进一步评估阿法替尼与 MEK 抑制联合治疗口腔鳞状细胞癌的临床应用。
