Sevelda Florian, Mayr Lisa, Kubista Bernd, Lötsch Daniela, van Schoonhoven Sushilla, Windhager Reinhard, Pirker Christine, Micksche Michael, Berger Walter
Department of Orthopaedics, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
Institute of Cancer Research and Comprehensive Cancer Center, Department of Medicine I, Medical University Vienna, Borschkegasse 8a, 1090, Vienna, Austria.
J Exp Clin Cancer Res. 2015 Nov 2;34:134. doi: 10.1186/s13046-015-0251-5.
Enhanced signalling via the epidermal growth factor receptor (EGFR) is a hallmark of multiple human carcinomas. However, in recent years data have accumulated that EGFR might also be hyperactivated in human sarcomas. Aim of this study was to investigate the influence of EGFR inhibition on cell viability and its interaction with chemotherapy response in osteosarcoma cell lines.
We have investigated a panel of human osteosarcoma cell lines regarding EGFR expression and downstream signalling. To test its potential applicability as therapeutic target, inhibition of EGFR by gefitinib was combined with osteosarcoma chemotherapeutics and cell viability, migration, and cell death assays were performed.
Osteosarcoma cells expressed distinctly differing levels of functional EGFR reaching in some cases high amounts. Functionality of EGFR in osteosarcoma cells was proven by EGF-mediated activation of both MAPK and PI3K/AKT pathway (determined by phosphorylation of ERK1/2, AKT, S6, and GSK3β). The EGFR-specific inhibitor gefitinib blocked EGF-mediated downstream signal activation. At standard in vitro culture conditions, clinically achievable gefitinib doses demonstrated only limited cytotoxic activity, however, significantly reduced long-term colony formation and cell migration. In contrast, under serum-starvation conditions active gefitinib doses were distinctly reduced while EGF promoted starvation survival. Importantly, gefitinib significantly supported the anti-osteosarcoma activities of doxorubicin and methotrexate regarding cell survival and migratory potential.
Our data suggest that EGFR is not a major driver for osteosarcoma cell growth but contributes to starvation- and chemotherapy-induced stress survival. Consequently, combination approaches including EGFR inhibitors should be evaluated for treatment of high-grade osteosarcoma patients.
通过表皮生长因子受体（EGFR）增强信号传导是多种人类癌症的一个标志。然而，近年来有数据表明，EGFR在人类肉瘤中也可能过度激活。本研究的目的是探讨EGFR抑制对骨肉瘤细胞系细胞活力的影响及其与化疗反应的相互作用。
我们研究了一组人类骨肉瘤细胞系的EGFR表达和下游信号传导。为了测试其作为治疗靶点的潜在适用性，将吉非替尼对EGFR的抑制作用与骨肉瘤化疗药物联合使用，并进行细胞活力、迁移和细胞死亡分析。
骨肉瘤细胞表达的功能性EGFR水平明显不同，在某些情况下含量很高。通过EGF介导的MAPK和PI3K/AKT途径的激活（通过ERK1/2、AKT、S6和GSK3β的磷酸化来确定），证明了EGFR在骨肉瘤细胞中的功能。EGFR特异性抑制剂吉非替尼阻断了EGF介导的下游信号激活。在标准体外培养条件下，临床可达到的吉非替尼剂量仅显示出有限的细胞毒性活性，然而，显著降低了长期集落形成和细胞迁移。相反，在血清饥饿条件下，活性吉非替尼剂量明显降低，而EGF促进饥饿存活。重要的是，吉非替尼在细胞存活和迁移潜力方面显著支持阿霉素和甲氨蝶呤的抗骨肉瘤活性。
我们的数据表明，EGFR不是骨肉瘤细胞生长的主要驱动因素，但有助于饥饿和化疗诱导的应激存活。因此，应评估包括EGFR抑制剂在内的联合治疗方法用于治疗高级别骨肉瘤患者。
