Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139, Milan, Italy.
Department of Otolaryngology-Head and Neck Surgery, Department of Pharmacology, Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI, USA.
Br J Cancer. 2019 Mar;120(6):658-667. doi: 10.1038/s41416-019-0394-9. Epub 2019 Feb 15.
Epidermal growth factor receptor (EGFR) overexpression is associated with the development of head and neck cancer (HNC) and represents one of the main therapeutic targets for this disease. The use of EGFR inhibitors has limited efficacy due to their primary and acquired resistance, partially because of increased epithelial to mesenchymal transition (EMT). The HDAC inhibitor SAHA has been shown to revert EMT in different tumours, including HNC. In this study, we investigated the cooperative role of SAHA and the EGFR tyrosine kinase inhibitor gefitinib in both HPV-positive and HPV-negative HNC cell lines.
A panel of 12 HPV-positive and HPV-negative HNC cell lines were screened for cell viability upon treatment with SAHA, gefitinib and the combination of the two. Epithelial/mesenchymal marker expression, as well as activation of signalling pathway, were assessed upon SAHA treatment. ΔNp63α silencing with shRNA lentiviral particles was used to determine its role in cell proliferation, migration and TGFβ pathway activation.
We found that both SAHA and gefitinib have antitumour activity in both HPV-positive and HPV-negative HNC cell lines and that their combination has a synergistic effect in inhibiting cell growth. SAHA treatment reverts EMT and inhibits the expression of the transcription factor ΔNp63α. Suppression of ΔNp63α reduces EGFR protein levels and decreases cell proliferation and TGFβ-dependent migration in both HPV-positive and HPV-negative HNC cell lines.
Our results, by giving a clear molecular mechanism at the basis of the antitumour activity of SAHA in HNC cell lines, provide a rationale for the clinical evaluation of SAHA in combination with gefitinib in both HPV-positive and HPV-negative HNC patients. Further knowledge is key to devising additional lines of combinatorial treatment strategies for this disease.
表皮生长因子受体（EGFR）过表达与头颈部癌症（HNC）的发生有关，是该疾病的主要治疗靶点之一。由于原发性和获得性耐药，EGFR 抑制剂的使用效果有限，部分原因是上皮间质转化（EMT）增加。组蛋白去乙酰化酶抑制剂 SAHA 已被证明可逆转包括 HNC 在内的不同肿瘤中的 EMT。在这项研究中，我们研究了 SAHA 和 EGFR 酪氨酸激酶抑制剂吉非替尼在 HPV 阳性和 HPV 阴性 HNC 细胞系中的协同作用。
筛选了一组 12 种 HPV 阳性和 HPV 阴性 HNC 细胞系，以评估 SAHA、吉非替尼及其联合用药对细胞活力的影响。用 SAHA 处理后，评估上皮/间质标志物表达以及信号通路的激活情况。利用 shRNA 慢病毒颗粒沉默 ΔNp63α，以确定其在细胞增殖、迁移和 TGFβ 通路激活中的作用。
我们发现，SAHA 和吉非替尼对 HPV 阳性和 HPV 阴性 HNC 细胞系均具有抗肿瘤活性，两者联合使用具有协同抑制细胞生长的作用。SAHA 处理可逆转 EMT 并抑制转录因子 ΔNp63α 的表达。ΔNp63α 的抑制降低了 HPV 阳性和 HPV 阴性 HNC 细胞系中 EGFR 蛋白水平，并减少了细胞增殖和 TGFβ 依赖性迁移。
我们的研究结果通过阐明 SAHA 在 HNC 细胞系中抗肿瘤活性的分子机制，为在 HPV 阳性和 HPV 阴性 HNC 患者中评估 SAHA 联合吉非替尼的临床应用提供了依据。进一步的研究是制定针对该疾病的联合治疗策略的关键。
