Phosphoproteomic analysis reveals Smarcb1 dependent EGFR signaling in Malignant Rhabdoid tumor cells

Abstract

BackgroundThe SWI/SNF ATP dependent chromatin remodeling complex is a multi-subunit complex, conserved in eukaryotic evolution that facilitates nucleosomal re-positioning relative to the DNA sequence. In recent years the SWI/SNF complex has emerged to play a role in cancer development as various sub-units of the complex are found to be mutated in a variety of tumors. One core-subunit of the complex, which has been well established as a tumor suppressor gene is SMARCB1 (SNF5/INI1/BAF47). Mutation and inactivation of SMARCB1 have been identified as the underlying mechanism leading to Malignant Rhabdoid Tumors (MRT) and Atypical Teratoid/Rhabdoid Tumors (AT/RT), two highly aggressive forms of pediatric neoplasms.MethodsWe present a phosphoproteomic study of Smarcb1 dependent changes in signaling networks. The SILAC (Stable Isotopic Labeling of Amino Acids in Cell Culture) protocol was used to quantify in an unbiased manner any changes in the phosphoproteomic profile of Smarcb1 deficient murine rhabdoid tumor cell lines following Smarcb1 stable re-expression and under different serum conditions.ResultsThis study illustrates broad changes in the regulation of multiple biological networks including cell cycle progression, chromatin remodeling, cytoskeletal regulation and focal adhesion. Specifically, we identify Smarcb1 dependent changes in phosphorylation and expression of the EGF receptor, demonstrate downstream signaling and show that inhibition of EGFR signaling specifically hinders the proliferation of Smarcb1 deficient cells.ConclusionsThese results support recent findings regarding the effectivity of EGFR inhibitors in hindering the proliferation of human MRT cells and demonstrate that activation of EGFR signaling in Rhabdoid tumors is SMARCB1 dependent.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-015-0439-5) contains supplementary material, which is available to authorized users.

Targeting SWI/SNF mutant cancers with tyrosine kinase inhibitor therapy

“…Similarly, Kuwahara et al found that RT cell lines displayed high levels of EGFR expression and inhibiting EGFR phosphorylation with the EGFR TKI gefitinib was capable of reducing cell growth both in vitro and in vivo [7]. These findings are consistent with a recent phosphoproteomic analysis of Smarcb1-deficient RT murine cells derived from a genetically engineered mouse model which showed that Smarcb1 loss led to the upregulation of EGFR phosphorylation and activation of the AKT pro-survival pathway [6]. Interestingly, in this study, lapatinib suppressed EGFR phosphorylation while gefitinib had the opposite effect of elevating receptor activation, although the mechanistic basis of this counterintuitive finding was not pursued.…”

“…Loss of SMARCB1 is a driver in a number of cancer types, including rhabdoid tumors (RTs), epithelioid sarcomas, renal medullary carcinoma, epithelioid malignant peripheral nerve sheath tumors, meningiomas and extraskeletal myxoid chondrosarcomas [5]. Tyrosine kinase dependencies associated with SMARCB1 deficiency have been most well studied in RTs and include oncogene addiction to the epidermal growth factor receptor (EGFR) and Human EGFR 2 (HER2) [6][7][8]. Screening three RT cell lines across a panel of 129 small molecular inhibitors, Singh et al showed that targeting EGFR-HER2 signaling using the EGFR-HER2 TKI lapatinib was effective in blocking tumor cell migration and inducing apoptosis in vitro [8].…”

Dual Targeting of PDGFRα and FGFR1 Displays Synergistic Efficacy in Malignant Rhabdoid Tumors

“…Wöhrle et al. (2013) showed that FGFR1 is upregulated when SMARCB1 is deleted in MRT cells, while Darr et al. (2015) recently demonstrated that EGFR expression is regulated by SMARCB1.…”

Sex difference in EGFR pathways in mouse kidney-potential impact on the immune system

“…As to Egfr , a considerable number of publications have indicated the consistency between the RNA expression level and protein level [49–51]. However, a relatively large number of genes including its ligands are in the pathways in regulation of Egfr .…”