Dataset Information

Inhibition of DHHC20-Mediated EGFR Palmitoylation Creates a Dependence on EGFR Signaling.

ABSTRACT: Inappropriate activation of the receptor tyrosine kinase EGFR contributes to a variety of human malignancies. Here we show a mechanism to induce vulnerability to an existing first line treatment for EGFR-driven cancers. We find that inhibiting the palmitoyltransferase DHHC20 creates a dependence on EGFR signaling for cancer cell survival. The loss of palmitoylation increases sustained EGFR signal activation and sensitizes cells to EGFR tyrosine kinase inhibition. Our work shows that the reversible modification of EGFR with palmitate "pins" the unstructured C-terminal tail to the plasma membrane, impeding EGFR activation. We identify by mass spectrometry palmitoylated cysteine residues within the C-terminal tail where mutation of the cysteine residues to alanine is sufficient to activate EGFR signaling promoting cell migration and transformation. Our results reveal that the targeting of a peripheral modulator of EGFR signaling, DHHC20, causes a loss of signal regulation and susceptibility to EGFR inhibitor-induced cell death.

SUBMITTER: Runkle KB

PROVIDER: S-EPMC4860254 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Inhibition of DHHC20-Mediated EGFR Palmitoylation Creates a Dependence on EGFR Signaling.

Runkle Kristin B KB Kharbanda Akriti A Stypulkowski Ewa E Cao Xing-Jun XJ Wang Wei W Garcia Benjamin A BA Witze Eric S ES

Molecular cell 20160501 3

Inappropriate activation of the receptor tyrosine kinase EGFR contributes to a variety of human malignancies. Here we show a mechanism to induce vulnerability to an existing first line treatment for EGFR-driven cancers. We find that inhibiting the palmitoyltransferase DHHC20 creates a dependence on EGFR signaling for cancer cell survival. The loss of palmitoylation increases sustained EGFR signal activation and sensitizes cells to EGFR tyrosine kinase inhibition. Our work shows that the reversib ...[more]

PMID: 27153536

Similar Datasets

Project description:Mucormycosis is a life-threatening, invasive fungal infection that is caused by various species belonging to the order Mucorales. Rhizopus species are the most common cause of the disease, responsible for approximately 70% of all cases of mucormycosis. During pulmonary mucormycosis, inhaled Rhizopus spores must adhere to and invade airway epithelial cells in order to establish infection. The molecular mechanisms that govern this interaction are poorly understood. We performed an unbiased survey of the host transcriptional response during early stages of Rhizopus arrhizus var. delemar (R. delemar) infection in a murine model of pulmonary mucormycosis using transcriptome sequencing (RNA-seq). Network analysis revealed activation of the host's epidermal growth factor receptor (EGFR) signaling. Consistent with the RNA-seq results, EGFR became phosphorylated upon in vitro infection of human alveolar epithelial cells with several members of the Mucorales, and this phosphorylated, activated form of EGFR colocalized with R. delemar spores. Inhibition of EGFR signaling with cetuximab or gefitinib, specific FDA-approved inhibitors of EGFR, significantly reduced the ability of R. delemar to invade and damage airway epithelial cells. Furthermore, gefitinib treatment significantly prolonged survival of mice with pulmonary mucormycosis, reduced tissue fungal burden, and attenuated the activation of EGFR in response to pulmonary mucormycosis. These results indicate EGFR represents a novel host target to block invasion of alveolar epithelial cells by R. delemar, and inhibition of EGFR signaling provides a novel approach for treating mucormycosis by repurposing an FDA-approved drug.IMPORTANCE Mucormycosis is an increasingly common, highly lethal fungal infection with very limited treatment options. Using a combination of in vivo animal models, transcriptomics, cell biology, and pharmacological approaches, we have demonstrated that Mucorales fungi activate EGFR signaling to induce fungal uptake into airway epithelial cells. Inhibition of EGFR signaling with existing FDA-approved drugs significantly increased survival following R. arrhizus var. delemar infection in mice. This study enhances our understanding of how Mucorales fungi invade host cells during the establishment of pulmonary mucormycosis and provides a proof-of-concept for the repurposing of FDA-approved drugs that target EGFR function.

Project description:Despite clinical approval of erlotinib, most advanced lung cancer patients are primary non-responders. Initial responders invariably develop secondary resistance, which can be accounted for by T790M-EGFR mutation in half of the relapses. We show that MET is highly expressed in lung cancer, often concomitantly with epidermal growth factor receptor (EGFR), including H1975 cell line. The erlotinib-resistant lung cancer cell line H1975, which expresses L858R/T790M-EGFR in-cis, was used to test for the effect of MET inhibition using the small molecule inhibitor SU11274. H1975 cells express wild-type MET, without genomic amplification (CNV = 1.1). At 2 microM, SU 11274 had significant in vitro pro-apoptotic effect in H1975 cells, 3.9-fold (P = 0.0015) higher than erlotinib, but had no effect on the MET and EGFR-negative H520 cells. In vivo, SU11274 also induced significant tumour cytoreduction in H1975 murine xenografts in our bioluminescence molecular imaging assay. Using small-animal microPET/MRI, SU11274 treatment was found to induce an early tumour metabolic response in H1975 tumour xenografts. MET and EGFR pathways were found to exhibit collaborative signalling with receptor cross-activation, which had different patterns between wild type (A549) and L858R/T790M-EGFR (H1975). SU11274 plus erlotinib/CL-387,785 potentiated MET inhibition of downstream cell proliferative survival signalling. Knockdown studies in H1975 cells using siRNA against MET alone, EGFR alone, or both, confirmed the enhanced downstream inhibition with dual MET-EGFR signal path inhibition. Finally, in our time-lapse video-microscopy and in vivo multimodal molecular imaging studies, dual SU11274-erlotinib concurrent treatment effectively inhibited H1975 cells with enhanced abrogation of cytoskeletal functions and complete regression of the xenograft growth. Together, our results suggest that MET-based targeted inhibition using small-molecule MET inhibitor can be a potential treatment strategy for T790M-EGFR-mediated erlotinib-resistant non-small-cell lung cancer. Furthermore, optimised inhibition may be further achieved with MET inhibition in combination with erlotinib or an irreversible EGFR-TKI.

Dataset Information

Inhibition of DHHC20-Mediated EGFR Palmitoylation Creates a Dependence on EGFR Signaling.

Publications

Inhibition of DHHC20-Mediated EGFR Palmitoylation Creates a Dependence on EGFR Signaling.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets