Expression and clinical relevance of MET and ALK in Ewing sarcomas

Abstract

Because novel therapeutic options are limited in Ewing sarcomas (ES), we investigated the expression, genetic aberrations and clinical relevance of MET and anaplastic lymphoma kinase (ALK) in ES and determined the relevance of targeting these receptors. MET and ALK protein expression was determined immunohistochemically in 31 (50 samples) and 36 (59 samples) ES patients, respectively. Samples included primary tumors, postchemotherapy resections, metastases and relapses. MET and ALK RTK domains were sequenced in respectively 33 and 32 tumors. Five ES cell lines were treated in vitro with the MET/ALKinhibitor crizotinib, the ALK-inhibitor NVP-TAE684 or the MET-inhibitor cabozantinib and analyzed by MTT assays. Modest to high MET and ALK expression was detected in the majority of ES (86 and 69%, respectively). ALK expression was significantly lower in postchemotherapy resections compared to paired untreated primary tumors (p 5 0.031, z 5 22.310, n 5 11). In primary tumors (n 5 20), membranous MET expression significantly correlated with a poor overall survival (OS) (60 vs. 197 months, p 5 0.014). There was a trend toward a poor event-free survival (67 vs. 111 months, p 5 0.078) and OS (88 vs. 128 months, p 5 0.074) in patients with highest ALK levels (n 5 29). ALK or MET RTK domain aberrations were demonstrated in 5/32 (16%) and 3/33 (9%) tumors, respectively. Crizotinib (IC 50 1.22-3.59 lmol/L), NVP-TAE684 (IC 50 0.15-0.79 lmol/L) and cabozantinib (IC 50 2.69-8.27 lmol/L) affected ES cell viability in vitro. Altogether, our data suggest that MET and ALK are potential novel therapeutic targets in ES and targeting these receptors may be of great interest to rationally design future studies in ES.Ewing sarcoma (ES) is the second most common primary malignant bone tumor occurring in children and adolescents. Although multimodal treatment has improved the prognosis of patients with localized ES during the last decades, the final outcome has not improved for patients with metastatic disease and side effects of treatment could be severe. 1,2 This urges the need for novel therapeutic strategies, including targeted therapies directed against molecules involved in the pathogenesis and progression of ES, 3 Although at present some receptor tyrosine kinases (RTKs) have been implicated in ES, predominantly the insulin-like growth factor-1 receptor (IGF-1R), and to a lesser extent also platelet-derived growth factor receptor (PDGFR) and c-KIT, the role of several other receptors remains to be investigated. 4 In this study, we addressed the role of MET and anaplastic lymphoma kinase (ALK) in ES.MET is a RTK known to be deregulated in many cancers. At present, the hepatocyte growth factor (HGF) is the only known ligand for MET. Upon receptor binding, MET undergoes rapid tyrosine phosphorylation and several intracellular signaling cascades are activated, including the phosphatidylinositol 3 (PI3)/Akt kinase and extracellular signal regulated kinase (Erk) pathways. Several studies have shown that HGF/ MET signaling is involved in c...

CRM1 Inhibition Promotes Cytotoxicity in Ewing Sarcoma Cells by Repressing EWS-FLI1–Dependent IGF-1 Signaling

“…Targeting c-MET is recognized as a promising opportunity for treatment of human cancers (38,39). Crizotinib is a c-MET/ALK inhibitor, which has previously been shown to have modest antineoplastic effect against EWS cells in vitro (40). In agreement with the prior study, we found crizotinib had a similar inhibitory effect on EWS cell lines, with an IC 50 about 2 mmol/L (Supplementary Fig.…”

Phosphoproteomic Profiling Reveals ALK and MET as Novel Actionable Targets across Synovial Sarcoma Subtypes

“…FISH was performed on 2-mm-thick formalin-fixed paraffin embedded (FFPE) tissue microarray (TMA) sections from the patient cohort described above, and an Aska-SS cytospin using an ALK (2p23) split-signal FISH DNA probe (Dako) as described previously (21).…”

“…RT-PCR and sequence analysis of the RTK domain of ALK and MET was performed on SS cell lines as described previously (21). SS cells were additionally screened with the Cancer Hotspot Panel with a focus on potential PDGFRa and EGFR mutations (23).…”

Targeting protein kinases to reverse multidrug resistance in sarcoma

“…Overexpression and aberrantly activated MET triggers cell growth, angiogenesis, invasion, and metastasis correlated with poor prognosis in various sarcomas 43, 44 . Targeting MET using the small molecule kinase inhibitor PHA-665752 and the neutralizing anti-HGF antibody sensitized osteosarcoma cells to cisplatin through suppression of the PI3K/AKT signaling 45 .…”