Froehlich2022 - Model of Adaptive Resistance in Melanoma
Ontology highlight
ABSTRACT: This model provides a thermodynamically consistent description of the action of MEK, RAF and panRAF inhibitors on EGFR and ERK signaling in BRAF mutant cancers.
Project description:The clinical efficacy of EGFR kinase inhibitors is limited by the development of drug resistance. The irreversible EGFR kinase inhibitor WZ4002 is effective against the most common mechanism of drug resistance mediated by the EGFR T790M mutation. Here we show that in multiple complementary models harboring EGFR T790M, resistance to WZ4002 develops through aberrant activation of ERK signaling caused by either an amplification of MAPK1 or by downregulation of negative regulators of ERK signaling. Inhibition of MEK or ERK restores sensitivity to WZ4002, and the combination of WZ4002 and a MEK inhibitor prevents the emergence of drug resistance. The WZ4002 resistant MAPK1 amplified cells also demonstrate an increase both in EGFR internalization and a decrease in sensitivity to cytotoxic chemotherapy compared to the parental counterparts. Our findings provide insights into mechanisms of drug resistance to EGFR kinase inhibitors and highlight rational combination therapies that should be evaluated in clinical trials. Our study identifies ERK signaling as a mediator of resistance to irreversible pyrimidine EGFR inhibitors in EGFR T790M-bearing cancers. We further provide a therapeutic strategy to both treat and prevent the emergence of this resistance mechanism. To generate drug-resistant NCI-H1975 cell lines, non-small cell lung cancer (NSCLC) cells were exposed to increasing concentrations of WZ4002 similar to previously described methods. Individual clones from WZ4002-resistant (WZR) cells were isolated and confirmed to be drug resistant. Clone #6, designated as WZR6, was used in this study. For expression analysis, samples were prepared in triplicate from parental NCI-H1975 and NCI-H1975 WZR6 cells.
Project description:The clinical efficacy of EGFR kinase inhibitors gefitinib and erlotinib is limited by the development of drug resistance. The most common mechanism of drug resistance is the secondary EGFR T790M mutation. Strategies to overcome EGFR T790M mediated drug resistance include the use of mutant selective EGFR inhibitors, including WZ4002, or by the use of high concentrations of irreversible quinazoline EGFR inhibitors such as PF299804. In the current study we develop drug resistant versions of the EGFR mutant PC9 cell line which reproducibly develops EGFR T790M as a mechanism of drug resistance to gefitinib. Neither PF299804 resistant (PFR) or WZ4002 resistant (WZR) clones of PC9 harbor EGFR T790M. Instead, they demonstrate activated IGF1R signaling as a result of loss of expression of IGFBP3 and the IGF1R inhibitor, BMS 536924, restores EGFR inhibitor sensitivity. Intriguingly, prolonged exposure to either PF299804 or WZ4002 results in the emergence of a more drug resistant subclone which contains ERK activation. A MEK inhibitor, CI-1040, partially restores sensitivity to EGFR/IGF1R inhibitor combination. Moreover, an IGF1R or MEK inhibitor used in combination with either PF299804 or WZ4002 completely prevents the emergence of drug resistant clones in this model system. Our studies suggest that more effective means of inhibiting EGFR T790M will prevent the emergence of this common drug resistance mechanism in EGFR mutant NSCLC. However, multiple drug resistance mechanisms can still emerge. Preventing the emergence of drug resistance, by targeting pathways activated in resistant cancers before they emerge, may be a more effective clinical strategy. Total of three samples with duplicate or triplicate each were analyzed.
Project description:The clinical efficacy of EGFR kinase inhibitors is limited by the development of drug resistance. The irreversible EGFR kinase inhibitor WZ4002 is effective against the most common mechanism of drug resistance mediated by the EGFR T790M mutation. Here we show that in multiple complementary models harboring EGFR T790M, resistance to WZ4002 develops through aberrant activation of ERK signaling caused by either an amplification of MAPK1 or by downregulation of negative regulators of ERK signaling. Inhibition of MEK or ERK restores sensitivity to WZ4002, and the combination of WZ4002 and a MEK inhibitor prevents the emergence of drug resistance. The WZ4002 resistant MAPK1 amplified cells also demonstrate an increase both in EGFR internalization and a decrease in sensitivity to cytotoxic chemotherapy compared to the parental counterparts. Our findings provide insights into mechanisms of drug resistance to EGFR kinase inhibitors and highlight rational combination therapies that should be evaluated in clinical trials. Our study identifies ERK signaling as a mediator of resistance to irreversible pyrimidine EGFR inhibitors in EGFR T790M-bearing cancers. We further provide a therapeutic strategy to both treat and prevent the emergence of this resistance mechanism.
Project description:The clinical efficacy of EGFR kinase inhibitors is limited by the development of drug resistance. The irreversible EGFR kinase inhibitor WZ4002 is effective against the most common mechanism of drug resistance mediated by the EGFR T790M mutation. Here we show that in multiple complementary models harboring EGFR T790M, resistance to WZ4002 develops through aberrant activation of ERK signaling caused by either an amplification of MAPK1 or by downregulation of negative regulators of ERK signaling. Inhibition of MEK or ERK restores sensitivity to WZ4002, and the combination of WZ4002 and a MEK inhibitor prevents the emergence of drug resistance. The WZ4002 resistant MAPK1 amplified cells also demonstrate an increase both in EGFR internalization and a decrease in sensitivity to cytotoxic chemotherapy compared to the parental counterparts. Our findings provide insights into mechanisms of drug resistance to EGFR kinase inhibitors and highlight rational combination therapies that should be evaluated in clinical trials. The EGFR mutant non-small cell lung cancer (NSCLC) cell line PC9 GR4 (delE746_A750/T790M) was exposed to increasing concentrations of WZ4002 similar to previously described methods. Individual clones from WZ4002-resistant (WZR) cells were isolated and confirmed to be drug resistant. Number of samples: 5. PC9GR4 as a control. 4 clones of WZ4002-resistant PC9GR4.
Project description:Pancreatic cancer is one of the most lethal cancers. Preclinical studies have shown adaptive resistance to Raf/MEK/ERK and PI3K/Akt pathway inhibition. We identify common protein expression alterations associated with adaptive resistance to MEK and PI3K kinase inhibition in KRas-mutant pancreatic cancer cells.
Project description:The clinical efficacy of EGFR kinase inhibitors gefitinib and erlotinib is limited by the development of drug resistance. The most common mechanism of drug resistance is the secondary EGFR T790M mutation. Strategies to overcome EGFR T790M mediated drug resistance include the use of mutant selective EGFR inhibitors, including WZ4002, or by the use of high concentrations of irreversible quinazoline EGFR inhibitors such as PF299804. In the current study we develop drug resistant versions of the EGFR mutant PC9 cell line which reproducibly develops EGFR T790M as a mechanism of drug resistance to gefitinib. Neither PF299804 resistant (PFR) or WZ4002 resistant (WZR) clones of PC9 harbor EGFR T790M. Instead, they demonstrate activated IGF1R signaling as a result of loss of expression of IGFBP3 and the IGF1R inhibitor, BMS 536924, restores EGFR inhibitor sensitivity. Intriguingly, prolonged exposure to either PF299804 or WZ4002 results in the emergence of a more drug resistant subclone which contains ERK activation. A MEK inhibitor, CI-1040, partially restores sensitivity to EGFR/IGF1R inhibitor combination. Moreover, an IGF1R or MEK inhibitor used in combination with either PF299804 or WZ4002 completely prevents the emergence of drug resistant clones in this model system. Our studies suggest that more effective means of inhibiting EGFR T790M will prevent the emergence of this common drug resistance mechanism in EGFR mutant NSCLC. However, multiple drug resistance mechanisms can still emerge. Preventing the emergence of drug resistance, by targeting pathways activated in resistant cancers before they emerge, may be a more effective clinical strategy.
Project description:The clinical efficacy of EGFR kinase inhibitors is limited by the development of drug resistance. The irreversible EGFR kinase inhibitor WZ4002 is effective against the most common mechanism of drug resistance mediated by the EGFR T790M mutation. Here we show that in multiple complementary models harboring EGFR T790M, resistance to WZ4002 develops through aberrant activation of ERK signaling caused by either an amplification of MAPK1 or by downregulation of negative regulators of ERK signaling. Inhibition of MEK or ERK restores sensitivity to WZ4002, and the combination of WZ4002 and a MEK inhibitor prevents the emergence of drug resistance. The WZ4002 resistant MAPK1 amplified cells also demonstrate an increase both in EGFR internalization and a decrease in sensitivity to cytotoxic chemotherapy compared to the parental counterparts. Our findings provide insights into mechanisms of drug resistance to EGFR kinase inhibitors and highlight rational combination therapies that should be evaluated in clinical trials.
Project description:This SuperSeries is composed of the following subset Series: GSE37698: Reactivation of ERK signaling causes resistance to EGFR kinase inhibitors (SNP array) GSE37699: Aberrant ERK signaling causes resistance to EGFR kinase inhibitors Refer to individual Series
Project description:NRAS activating mutations occur in 15-25% of melanoma patients. However, this subtype is more aggressive and refractory to current treatment modalities, including targeted MEK inhibitors, immunotherapies, and the recently emerging RAS inhibitors. Accordingly, identifying novel therapeutic targets and designing novel antimelanoma strategies is of utmost clinical relevance. Melanomas often harbor hyperactive nitric oxide synthases (NOS) which correlates strongly with poor prognosis. NOS is also known to be activated by ERK signaling. The nitric oxide so produced, induces nitrosylation, a post-translational modification, which dysregulates various kinases and phosphatases. We sensitized NRAS-mutant melanomas to targeted MEK inhibitors by inhibiting nitrosylation. This outcome revealed a strong correlation between global de-nitrosylation and downregulation of MEK-ERK cascade with a concomitant de-nitrosylation of NRAS and other small GTPases like Rho and Rac, dual specificity phosphatases, and ribosomal S6 kinase. In vivo, we observed extreme regression of NRAS-mutant melanoma tumors generated in an immunocompetent mouse model in response to a sequential nitrosylation inhibition and MEK inhibition. In addition to MEK-ERK downregulation, this strategy activated the CD8+ T cells in the tumor microenvironment. We conclude that while nitrosylation hyperactivates the RAS-RAF-MEK-ERK cascade, it also suppresses anti-melanoma immune response, bolstering progression and MEKi resistance. The underlying mechanism(s) will be crucial in identifying novel therapeutic vulnerabilities against aggressive, currently incurable NRAS-mutant melanomas with potential clinical application in other melanoma subtypes.
Project description:Small cell lung cancer (SCLC) transformation is an incompletely characterized mechanism of resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in EGFR mutant cancers, limiting development of optimal treatment approaches. Through single-cell RNA sequencing of malignant pleural effusions from patients who underwent SCLC transformation, we identified heterogeneity and diversity including distinct neuroendocrine (NE) and mesenchymal non-NE cancer cell subsets, which was maintained in patient-derived cell lines. We demonstrate that EZH2 regulates EGFR expression in NE cells where EGFR expression is silenced at baseline. Although neither epigenetic derepression nor exogenous overexpression of mutant EGFR sensitized the cells to EGFR inhibition, non-NE cells exhibited selective sensitivity to MEK inhibitors. Combined MEK inhibitor and chemotherapy effectively inhibited growth of both NE and non-NE cells in vitro and in vivo. Our findings demonstrate that EGFR mutant SCLC is composed of mixed cell states with distinct therapeutic vulnerabilities and offer a novel therapeutic strategy to target tumor heterogeneity in highly plastic and treatment-resistant malignancies such as SCLC transformed cancers.