EGFR inhibitors identified as a potential treatment for chordoma in a focused compound screen

Abstract

Chordoma is a rare malignant bone tumour with a poor prognosis and limited therapeutic options. We undertook a focused compound screen (FCS) against 1097 compounds on three well‐characterized chordoma cell lines; 154 compounds were selected from the single concentration screen (1 µm), based on their growth‐inhibitory effect. Their half‐maximal effective concentration (EC50) values were determined in chordoma cells and normal fibroblasts. Twenty‐seven of these compounds displayed chordoma selective cell kill and 21/27 (78%) were found to be EGFR/ERBB family inhibitors. EGFR inhibitors in clinical development were then studied on an extended cell line panel of seven chordoma cell lines, four of which were sensitive to EGFR inhibition. Sapitinib (AstraZeneca) emerged as the lead compound, followed by gefitinib (AstraZeneca) and erlotinib (Roche/Genentech). The compounds were shown to induce apoptosis in the sensitive cell lines and suppressed phospho‐EGFR and its downstream pathways in a dose‐dependent manner. Analysis of substituent patterns suggested that EGFR‐inhibitors with small aniline substituents in the 4‐position of the quinazoline ring were more effective than inhibitors with large substituents in that position. Sapitinib showed significantly reduced tumour growth in two xenograft mouse models (U‐CH1 xenograft and a patient‐derived xenograft, SF8894). One of the resistant cell lines (U‐CH2) was shown to express high levels of phospho‐MET, a known bypass signalling pathway to EGFR. Neither amplifications (EGFR, ERBB2, MET) nor mutations in EGFR, ERBB2, ERBB4, PIK3CA, BRAF, NRAS, KRAS, PTEN, MET or other cancer gene hotspots were detected in the cell lines. Our findings are consistent with the reported (p‐)EGFR expression in the majority of clinical samples, and provide evidence for exploring the efficacy of EGFR inhibitors in the treatment of patients with chordoma and studying possible resistance mechanisms to these compounds in vitro and in vivo. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

ErbB1 and ErbB4 generate opposing signals regulating mesenchymal cell proliferation during valvulogenesis

“…This inhibitor specifically inhibits ErbB1 activity among ErbB RTKs (Scheipl et al, 2016). ZD1839 upregulated WT cell proliferation, as observed previously (Iwamoto et al, 2010).…”

Y‐box binding protein‐1 promotes tumorigenesis and progression via the epidermal growth factor receptor/AKT pathway in spinal chordoma

“…Abnormal activation of the EGFR‐mediated pathway is reported to promote tumor invasion ability and development of chordoma. Previous studies indicated that EGFR inhibitor markedly diminished EGFR phosphorylation in a dose‐dependent manner and suppressed proliferation of the chordoma in vitro and vivo . EGFR was transcriptionally induced by YBX1 in breast cancer and glioma .…”

“…Unfortunately, more than 40% of patients present with local recurrence, and metastases occur in 40%‐60% of patients during follow‐up. There is currently no standard medical therapy for chordoma . Although various biomarkers in chordoma have been identified in recent years, the underlying molecular mechanisms regulating tumorgenesis and progression of chordoma are not fully understood.…”

“…In addition, YBX1 regulates tumor cell proliferation, apoptosis, invasion, migration and chemoresistance through the related pathways . Multiple key molecules that interact with YBX1 have been shown to be overexpressed in chordoma and contribute to chordoma development, such as hypoxia inducible factor 1 alpha subunit (HIF‐1α), a mechanistic target of rapamycin kinase (mTOR) and RB transcriptional corepressor 1 (RB) …”

An update of molecular pathology of bone tumors. Lessons learned from investigating samples by next generation sequencing

“…Clinically actionable PI3K signaling mutations including PIK3CA , PIK3R1 , and PTEN have been identified in 16% of cases, although clinical trials are required to determine the clinical value of such targeted therapies. Although EGFR mutations have not been identified in chordomas, the phosphorylated protein is expressed in the majority of cases, and therapeutic compounds have been found to induce chordoma cell death in vitro . This research has resulted in the opening of a recent phase II clinical trial using Afatinib, a third generation EGFR inhibitor.…”