RESUMO
Aerobic glycolysis or the Warburg effect (WE) is characterized by increased glucose uptake and incomplete oxidation to lactate. Although the WE is ubiquitous, its biological role remains controversial, and whether glucose metabolism is functionally different during fully oxidative glycolysis or during the WE is unknown. To investigate this question, here we evolved resistance to koningic acid (KA), a natural product that specifically inhibits glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a rate-controlling glycolytic enzyme, during the WE. We found that KA-resistant cells lose the WE but continue to conduct glycolysis and surprisingly remain dependent on glucose as a carbon source and also on central carbon metabolism. Consequently, this altered state of glycolysis led to differential metabolic activity and requirements, including emergent activities in and dependences on fatty acid metabolism. These findings reveal that aerobic glycolysis is a process functionally distinct from conventional glucose metabolism and leads to distinct metabolic requirements and biological functions.
Assuntos
Gliceraldeído-3-Fosfato Desidrogenase (Fosforiladora)/metabolismo , Glicólise , Oxigênio/metabolismo , Inibidores Enzimáticos/farmacologia , Ácidos Graxos/metabolismo , Glucose/metabolismo , Gliceraldeído-3-Fosfato Desidrogenase (Fosforiladora)/antagonistas & inibidores , Gliceraldeído-3-Fosfato Desidrogenase (Fosforiladora)/genética , Humanos , Células MCF-7 , Sesquiterpenos/farmacologiaRESUMO
The inhibitory epidermal growth factor receptor (EGFR) antibody, cetuximab, is an approved therapy for head and neck squamous cell carcinoma (HNSCC). Despite tumor response observed in some HNSCC patients, cetuximab alone or combined with radio- or chemotherapy fails to yield long-term control or cures. We hypothesize that a flexible receptor tyrosine kinase coactivation signaling network supports HNSCC survival in the setting of EGFR blockade, and that drugs disrupting this network will provide superior tumor control when combined with EGFR inhibitors. In this work, we submitted EGFR-dependent HNSCC cell lines to RNA interference-based functional genomics screens to identify, in an unbiased fashion, essential protein kinases for growth and survival as well as synthetic lethal targets for combined inhibition with EGFR antagonists. Mechanistic target of rapamycin kinase (MTOR) and erythroblastosis oncogene B (ERBB)3 were identified as high-ranking essential kinase hits in the HNSCC cell lines. MTOR dependency was confirmed by distinct short hairpin RNAs (shRNAs) and high sensitivity of the cell lines to AZD8055, whereas ERBB3 dependency was validated by shRNA-mediated silencing. Furthermore, a synthetic lethal kinome shRNA screen with a pan-ERBB inhibitor, AZD8931, identified multiple components of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase pathway, consistent with ERK reactivation and/or incomplete ERK pathway inhibition in response to EGFR inhibitor monotherapy. As validation, distinct mitogen-activated protein kinase kinase (MEK) inhibitors yielded synergistic growth inhibition when combined with the EGFR inhibitors, gefitinib and AZD8931. The findings identify ERBB3 and MTOR as important pharmacological vulnerabilities in HNSCC and support combining MEK and EGFR inhibitors to enhance clinical efficacy in HNSCC. SIGNIFICANCE STATEMENT: Many cancers are driven by nonmutated receptor tyrosine kinase coactivation networks that defy full inhibition with single targeted drugs. This study identifies erythroblastosis oncogene B (ERBB)3 as an essential protein kinase in epidermal growth factor receptor-dependent head and neck squamous cell cancer (HNSCC) cell lines and a synthetic lethal interaction with the extracellular signal-regulated kinase mitogen-activated protein kinase pathway that provides a rationale for combining pan-ERBB and mitogen-activated protein kinase inhibitors as a therapeutic approach in subsets of HNSCC.
Assuntos
Proteínas Quinases/metabolismo , Interferência de RNA/fisiologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Animais , Linhagem Celular Tumoral , Receptores ErbB/genética , Receptores ErbB/metabolismo , Células HEK293 , Humanos , Camundongos , Proteínas Quinases/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço/genéticaRESUMO
MOTIVATION: Non-small-cell lung cancer (NSCLC) is the leading cause of cancer death in the United States. Targeted tyrosine kinase inhibitors (TKIs) directed against the epidermal growth factor receptor (EGFR) have been widely and successfully used in treating NSCLC patients with activating EGFR mutations. Unfortunately, the duration of response is short-lived, and all patients eventually relapse by acquiring resistance mechanisms. RESULT: We performed an integrative systems biology approach to determine essential kinases that drive EGFR-TKI resistance in cancer cell lines. We used a series of bioinformatics methods to analyze and integrate the functional genetics screen and RNA-seq data to identify a set of kinases that are critical in survival and proliferation in these TKI-resistant lines. By connecting the essential kinases to compounds using a novel kinase connectivity map (K-Map), we identified and validated bosutinib as an effective compound that could inhibit proliferation and induce apoptosis in TKI-resistant lines. A rational combination of bosutinib and gefitinib showed additive and synergistic effects in cancer cell lines resistant to EGFR TKI alone. CONCLUSIONS: We have demonstrated a bioinformatics-driven discovery roadmap for drug repurposing and development in overcoming resistance in EGFR-mutant NSCLC, which could be generalized to other cancer types in the era of personalized medicine. AVAILABILITY AND IMPLEMENTATION: K-Map can be accessible at: http://tanlab.ucdenver.edu/kMap. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Carcinoma Pulmonar de Células não Pequenas/genética , Receptores ErbB/genética , Neoplasias Pulmonares/genética , Inibidores de Proteínas Quinases/farmacologia , Compostos de Anilina/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Linhagem Celular Tumoral , Biologia Computacional , Resistencia a Medicamentos Antineoplásicos/genética , Gefitinibe , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Mutação , Nitrilas/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Quinases/genética , Quinazolinas/farmacologia , Quinolinas/farmacologia , Análise de Sequência de RNARESUMO
Cancers with acquired resistance to targeted therapy can become simultaneously dependent on the presence of the targeted therapy drug for survival, suggesting that intermittent therapy may slow resistance. However, relatively little is known about which tumours are likely to become dependent and how to schedule intermittent therapy optimally. Here we characterized drug dependence across a panel of over 75 MAPK-inhibitor-resistant BRAFV600E mutant melanoma models at the population and single-clone levels. Melanocytic differentiated models exhibited a much greater tendency to give rise to drug-dependent progeny than their dedifferentiated counterparts. Mechanistically, acquired loss of microphthalmia-associated transcription factor in differentiated melanoma models drives ERK-JunB-p21 signalling to enforce drug dependence. We identified the optimal scheduling of 'drug holidays' using simple mathematical models that we validated across short and long timescales. Without detailed knowledge of tumour characteristics, we found that a simple adaptive therapy protocol can produce near-optimal outcomes using only measurements of total population size. Finally, a spatial agent-based model showed that optimal schedules derived from exponentially growing cells in culture remain nearly optimal in the context of tumour cell turnover and limited environmental carrying capacity. These findings may guide the implementation of improved evolution-inspired treatment strategies for drug-dependent cancers.
Assuntos
Melanoma , Transtornos Relacionados ao Uso de Substâncias , Humanos , Melanoma/tratamento farmacológico , Melanoma/patologia , Resistencia a Medicamentos Antineoplásicos , Inibidores de Proteínas Quinases/farmacologia , Linhagem Celular Tumoral , Transtornos Relacionados ao Uso de Substâncias/tratamento farmacológicoRESUMO
Hypermobile Ehlers-Danlos syndrome (hEDS) is a common heritable connective tissue disorder that lacks a known genetic etiology. To identify genetic contributions to hEDS, whole exome sequencing was performed on families and a cohort of sporadic hEDS patients. A missense variant in Kallikrein-15 (KLK15 p. Gly226Asp), segregated with disease in two families and genetic burden analyses of 197 sporadic hEDS patients revealed enrichment of variants within the Kallikrein gene family. To validate pathogenicity, the variant identified in familial studies was used to generate knock-in mice. Consistent with our clinical cohort, Klk15 G224D/+ mice displayed structural and functional connective tissue defects within multiple organ systems. These findings support Kallikrein gene variants in the pathogenesis of hEDS and represent an important step towards earlier diagnosis and better clinical outcomes.
RESUMO
Our laboratory has previously shown that some gefitinib-insensitive head and neck squamous cell carcinoma (HNSCC) cell lines exhibit dominant autocrine fibroblast growth factor receptor (FGFR) signaling. Herein, we deployed a whole-genome loss-of-function screen to identify genes whose knockdown potentiated the inhibitory effect of the FGFR inhibitor, AZ8010, in HNSCC cell lines. Three HNSCC cell lines expressing a genome-wide small hairpin RNA (shRNA) library were treated with AZ8010 and the abundance of shRNA sequences was assessed by deep sequencing. Under-represented shRNAs in treated cells are expected to target genes important for survival with AZ8010 treatment. Synthetic lethal hits were validated with specific inhibitors and independent shRNAs. We found that multiple alternate receptors provided protection from FGFR inhibition, including receptor tyrosine kinases (RTKs), v-erb-b2 erythroblastic leukemia viral oncogene homolog 2 (ERBB2), and hepatocyte growth factor receptor (MET). We showed that specific knockdown of either ERBB2 or MET in combination with FGFR inhibition led to increased inhibition of growth relative to FGFR tyrosine kinase inhibitor (TKI) treatment alone. These results were confirmed using specific small molecule inhibitors of either ERBB family members or MET. Moreover, the triple combination of FGFR, MET, and ERBB family inhibitors showed the largest inhibition of growth and induction of apoptosis compared with the double combinations. These results reveal a role for alternate RTKs in maintaining progrowth and survival signaling in HNSCC cells in the setting of FGFR inhibition. Thus, improved therapies for HNSCC patients could involve rationally designed combinations of TKIs targeting FGFR, ERBB family members, and MET.
Assuntos
Receptores ErbB/fisiologia , Neoplasias de Cabeça e Pescoço/patologia , Proteínas Oncogênicas v-erbB/fisiologia , Proteínas Proto-Oncogênicas c-met/fisiologia , Receptor ErbB-2/fisiologia , Receptores de Fatores de Crescimento de Fibroblastos/fisiologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Receptores ErbB/antagonistas & inibidores , Redes Reguladoras de Genes/efeitos dos fármacos , Redes Reguladoras de Genes/fisiologia , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/metabolismo , Humanos , Proteínas Oncogênicas v-erbB/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Quinazolinas/farmacologia , Quinazolinas/uso terapêutico , Receptores Proteína Tirosina Quinases/fisiologia , Receptor ErbB-2/antagonistas & inibidores , Receptores de Fatores de Crescimento de Fibroblastos/antagonistas & inibidoresRESUMO
Targeted therapies have revolutionized cancer chemotherapy. Unfortunately, most patients develop multifocal resistance to these drugs within a matter of months. Here, we used a high-throughput phenotypic small molecule screen to identify MCB-613 as a compound that selectively targets EGFR-mutant, EGFR inhibitor-resistant non-small cell lung cancer (NSCLC) cells harboring diverse resistance mechanisms. Subsequent proteomic and functional genomic screens involving MCB-613 identified its target in this context to be KEAP1, revealing that this gene is selectively essential in the setting of EGFR inhibitor resistance. In-depth molecular characterization demonstrated that (1) MCB-613 binds KEAP1 covalently; (2) a single molecule of MCB-613 is capable of bridging two KEAP1 monomers together; and, (3) this modification interferes with the degradation of canonical KEAP1 substrates such as NRF2. Surprisingly, NRF2 knockout sensitizes cells to MCB-613, suggesting that the drug functions through modulation of an alternative KEAP1 substrate. Together, these findings advance MCB-613 as a new tool for exploiting the selective essentiality of KEAP1 in drug-resistant, EGFR-mutant NSCLC cells.
RESUMO
Local adaptation directs populations towards environment-specific fitness maxima through acquisition of positively selected traits. However, rapid environmental changes can identify hidden fitness trade-offs that turn adaptation into maladaptation, resulting in evolutionary traps. Cancer, a disease that is prone to drug resistance, is in principle susceptible to such traps. We therefore performed pooled CRISPR-Cas9 knockout screens in acute myeloid leukemia (AML) cells treated with various chemotherapies to map the drug-dependent genetic basis of fitness trade-offs, a concept known as antagonistic pleiotropy (AP). We identified a PRC2-NSD2/3-mediated MYC regulatory axis as a drug-induced AP pathway whose ability to confer resistance to bromodomain inhibition and sensitivity to BCL-2 inhibition templates an evolutionary trap. Across diverse AML cell-line and patient-derived xenograft models, we find that acquisition of resistance to bromodomain inhibition through this pathway exposes coincident hypersensitivity to BCL-2 inhibition. Thus, drug-induced AP can be leveraged to design evolutionary traps that selectively target drug resistance in cancer.
Assuntos
Resistencia a Medicamentos Antineoplásicos/genética , Pleiotropia Genética/genética , Neoplasias/genética , Adaptação Fisiológica/genética , Animais , Evolução Biológica , Sistemas CRISPR-Cas/genética , Linhagem Celular , Linhagem Celular Tumoral , Meio Ambiente , Aptidão Genética/genética , Células HEK293 , Células HL-60 , Humanos , Camundongos , Proteínas Nucleares/genética , Fenótipo , Locos de Características Quantitativas/genética , Fatores de Transcrição/genéticaRESUMO
The goal of this study was to determine if the high [K(+)] in tears, 20-25 mM, serves to protect corneal epithelial cells from going into apoptosis after exposure to ambient UV-B radiation. Human corneal-limbal epithelial (HCLE) cells in culture were exposed to UV-B at doses of 50-200 mJ/cm(2) followed by measurement of K(+) channel activation and activity of apoptotic pathways. Patch-clamp recording showed activation of K(+) channels after UV-B exposure at 80 mJ/cm(2) or 150 mJ/cm(2) and a decrease in UV-induced K(+) efflux with increasing [K(+)](o). The UV-activated current was partially blocked by the specific K(+) channel blocker, BDS-1. DNA fragmentation, as measured by the TUNEL assay, was induced after exposure to UV-B at 100-200 mJ/cm(2). DNA fragmentation was significantly decreased when cells were incubated in 25, 50 or 100mM K(o)(+) after exposure to UV-B. The effector caspase, caspase-3, was activated by exposure to UV-B at 50-200 mJ/cm(2), but there was a significant decrease in activation when the cells were incubated in 25, 50 or 100mM K(o)(+) following exposure to UV-B. A decrease in mitochondrial potential, a possible activator of caspase-3, occurred after exposure to UV-B at 100-200 mJ/cm(2). This decrease in mitochondrial potential was prevented by 100mM K(o)(+); however, 25 or 50mM K(o)(+) provided minimal protection. Caspase-9, which is in the pathway from mitochondrial potential change to caspase-3 activation, showed little activation by UV-B radiation. Caspase-8, an initiator caspase that activates caspase-3, was activated by exposure to UV-B at 50-200 mJ/cm(2), and this UV-activation was significantly reduced by 25-100mM K(o)(+). The data show that the physiologically relevant [K(+)](o) of 25 mM can inhibit UV-B induced activation of apoptotic pathways. This suggests that the relatively high [K(+)] in tears reduces loss of K(+) from corneal epithelial cells in response to UV exposure, thereby contributing to the protection of the ocular surface from ambient UV radiation.
Assuntos
Apoptose/efeitos da radiação , Epitélio Corneano/efeitos da radiação , Canais de Potássio/fisiologia , Raios Ultravioleta , Apoptose/fisiologia , Caspases/metabolismo , Linhagem Celular Transformada , Células Cultivadas , Fragmentação do DNA , Relação Dose-Resposta à Radiação , Ativação Enzimática/efeitos dos fármacos , Epitélio Corneano/citologia , Epitélio Corneano/metabolismo , Humanos , Marcação In Situ das Extremidades Cortadas , Potencial da Membrana Mitocondrial/fisiologia , Potencial da Membrana Mitocondrial/efeitos da radiação , Técnicas de Patch-Clamp , Canais de Potássio/efeitos da radiação , Transdução de Sinais/efeitos da radiaçãoRESUMO
A subset of lung cancers is dependent on the anaplastic lymphoma kinase (ALK) oncogene for survival, a mechanism that is exploited by the use of the ALK inhibitor crizotinib. Despite exceptional initial tumor responses to ALK inhibition by crizotinib, durable clinical response is limited and the emergence of drug resistance occurs. Furthermore, intrinsic resistance is frequently observed, where patients fail to respond initially to ALK-inhibitor therapy. These events demonstrate the underlying complexity of a molecularly-defined oncogene-driven cancer and highlights the need to identify compensating survival pathways. Using a loss-of-function whole genome short-hairpin (shRNA) screen, we identified MYCBP as a determinant of response to crizotinib, implicating the MYC signaling axis in resistance to crizotinib-treated ALK+ NSCLC. Further analysis reveals that ALK regulates transcriptional expression of MYC and activates c-MYC transactivation of c-MYC target genes. Inhibition of MYC by RNAi or small molecules sensitizes ALK+ cells to crizotinib. Taken together, our findings demonstrate a dual oncogene mechanism, where ALK positively regulates the MYC signaling axis, providing an additional oncogene target whose inhibition may prevent or overcome resistance.
RESUMO
The clinical success of tyrosine kinase inhibitors specific for BCR-ABL-, EGFR-, ALK-, and ROS1-driven cancers continues to spur the quest to match specific oncogene-defined tumor types with an appropriate molecularly targeted therapy. Unfortunately, responses to these agents are not durable with intrinsic or acquired resistance limiting benefit. Additionally, efforts to identify the appropriate targets of new drugs have focused on nonfunctional assays such as large-scale sequencing for somatic mutations or analysis of gene copy number. Acknowledging both the problem of resistance and the shortcomings of the current methods for detecting appropriate drug targets, much interest has been focused on RNAi-based screens. These screens utilize a library of shRNAs targeting the whole genome or a subset of genes and provide a high-throughput and unbiased means to functionally assess genes impacting various aspects of tumor biology, especially proliferation and survival. The function of genes can be measured in the context of a specific drug treatment, termed a synthetic lethal screen, or genes may be assessed for their individual dependency, termed an essential gene screen. Here, we describe a method for performing both of these types of screens using a kinome-targeted shRNA library in human cancer cell lines.
Assuntos
Antineoplásicos/farmacologia , Resistência a Medicamentos/efeitos dos fármacos , Resistência a Medicamentos/genética , Genômica/métodos , Inibidores de Proteínas Quinases/farmacologia , Linhagem Celular , Biblioteca Gênica , Genes Essenciais , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , RNA Interferente Pequeno/genética , Análise de Sequência de DNA , Mutações Sintéticas LetaisRESUMO
Diverse pathways drive resistance to BRAF/MEK inhibitors in BRAF-mutant melanoma, suggesting that durable control of resistance will be a challenge. By combining statistical modeling of genomic data from matched pre-treatment and post-relapse patient tumors with functional interrogation of >20 in vitro and in vivo resistance models, we discovered that major pathways of resistance converge to activate the transcription factor, c-MYC (MYC). MYC expression and pathway gene signatures were suppressed following drug treatment, and then rebounded during progression. Critically, MYC activation was necessary and sufficient for resistance, and suppression of MYC activity using genetic approaches or BET bromodomain inhibition was sufficient to resensitize cells and delay BRAFi resistance. Finally, MYC-driven, BRAFi-resistant cells are hypersensitive to the inhibition of MYC synthetic lethal partners, including SRC family and c-KIT tyrosine kinases, as well as glucose, glutamine, and serine metabolic pathways. These insights enable the design of combination therapies that select against resistance evolution.
Assuntos
Melanoma/tratamento farmacológico , Proteínas Proto-Oncogênicas c-myc/metabolismo , Antineoplásicos Hormonais/uso terapêutico , Benzimidazóis/farmacologia , Linhagem Celular Tumoral , Estradiol/análogos & derivados , Estradiol/uso terapêutico , Evolução Molecular , Feminino , Fulvestranto , Humanos , Imidazóis/farmacologia , Imidazóis/uso terapêutico , Indóis/farmacologia , Masculino , Oximas/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Proteínas Proto-Oncogênicas B-raf/metabolismo , Piridonas/uso terapêutico , Pirimidinonas/uso terapêutico , Quinolinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Sulfonamidas/farmacologiaRESUMO
Functional genomics approaches such as gain- and loss-of-function screening can efficiently reveal genes that control cancer cell growth, survival, signal transduction, and drug resistance, but distilling the results of large-scale screens into actionable therapeutic strategies is challenging given our incomplete understanding of the functions of many genes. Research over several decades, including the results of large-scale cancer sequencing projects, has made it clear that many oncogenic properties are controlled by a common set of core oncogenic signaling pathways. By directly screening this core set of pathways, rather than much larger numbers of individual genes, it may be possible to more directly and efficiently connect functional genomic screening results with therapeutic targets. Here, we describe the recent development of methods to directly screen oncogenic pathways in high-throughput. We summarize the results of studies that have used pathway-centric screening to map the pathways of resistance to targeted therapies in diverse cancer types, then conclude by expanding on potential future applications of this approach.
RESUMO
The FGFR1 is a therapeutic target under investigation in multiple solid tumors and clinical trials of selective tyrosine kinase inhibitors (TKI) are underway. Treatment with a single TKI represents a logical step toward personalized cancer therapy, but intrinsic and acquired resistance mechanisms limit their long-term benefit. In this study, we deployed RNAi-based functional genomic screens to identify protein kinases controlling the intrinsic sensitivity of FGFR1-dependent lung cancer and head and neck squamous cell cancer (HNSCC) cells to ponatinib, a multikinase FGFR-active inhibitor. We identified and validated a synthetic lethal interaction between MTOR and ponatinib in non-small cell lung carcinoma cells. In addition, treatment with MTOR-targeting shRNAs and pharmacologic inhibitors revealed that MTOR is an essential protein kinase in other FGFR1-expressing cancer cells. The combination of FGFR inhibitors and MTOR or AKT inhibitors resulted in synergistic growth suppression in vitro. Notably, tumor xenografts generated from FGFR1-dependent lung cancer cells exhibited only modest sensitivity to monotherapy with the FGFR-specific TKI, AZD4547, but when combined with the MTOR inhibitor, AZD2014, significantly attenuated tumor growth and prolonged survival. Our findings support the existence of a signaling network wherein FGFR1-driven ERK and activated MTOR/AKT represent distinct arms required to induce full transformation. Furthermore, they suggest that clinical efficacy of treatments for FGFR1-driven lung cancers and HNSCC may be achieved by combining MTOR inhibitors and FGFR-specific TKIs.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Interferência de RNA , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Animais , Antineoplásicos/farmacologia , Benzamidas/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos , Sinergismo Farmacológico , Biblioteca Gênica , Genes Essenciais , Genômica/métodos , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Morfolinas/farmacologia , Piperazinas/farmacologia , Ligação Proteica , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Pirazóis/farmacologia , Pirimidinas , RNA Interferente Pequeno/genética , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genética , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/genética , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The epidermal growth factor receptor (EGFR) is overexpressed in approximately 90% of head and neck squamous cell carcinomas (HNSCC), and molecularly targeted therapy against the EGFR with the monoclonal antibody cetuximab modestly increases overall survival in head and neck cancer patients. We hypothesize that co-signaling through additional pathways limits the efficacy of cetuximab and EGFR-specific tyrosine kinase inhibitors (TKIs) in the clinical treatment of HNSCC. Analysis of gene expression changes in HNSCC cell lines treated 4 days with TKIs targeting EGFR and/or fibroblast growth factor receptors (FGFRs) identified transforming growth factor beta 2 (TGF-ß2) induction in the three cell lines tested. Measurement of TGF-ß2 mRNA validated this observation and extended it to additional cell lines. Moreover, TGF-ß2 mRNA was increased in primary patient HNSCC xenografts treated for 4 weeks with cetuximab, demonstrating in vivo relevance of these findings. Functional genomics analyses with shRNA libraries identified TGF-ß2 and TGF-ß receptors (TGFßRs) as synthetic lethal genes in the context of TKI treatment. Further, direct RNAi-mediated silencing of TGF-ß2 inhibited cell growth, both alone and in combination with TKIs. Also, a pharmacological TGFßRI inhibitor similarly inhibited basal growth and enhanced TKI efficacy. In summary, the studies support a TGF-ß2-TGFßR pathway as a TKI-inducible growth pathway in HNSCC that limits efficacy of EGFR-specific inhibitors.
Assuntos
Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Cetuximab/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Fator de Crescimento Transformador beta2/metabolismo , Linhagem Celular Tumoral , Humanos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/antagonistas & inibidores , Receptores de Fatores de Crescimento Transformadores beta/genética , Transdução de Sinais/efeitos dos fármacos , Fator de Crescimento Transformador beta2/genéticaRESUMO
Cancer cells can activate diverse signaling pathways to evade the cytotoxic action of drugs. We created and screened a library of barcoded pathway-activating mutant complementary DNAs to identify those that enhanced the survival of cancer cells in the presence of 13 clinically relevant, targeted therapies. We found that activation of the RAS-MAPK (mitogen-activated protein kinase), Notch1, PI3K (phosphoinositide 3-kinase)-mTOR (mechanistic target of rapamycin), and ER (estrogen receptor) signaling pathways often conferred resistance to this selection of drugs. Activation of the Notch1 pathway promoted acquired resistance to tamoxifen (an ER-targeted therapy) in serially passaged breast cancer xenografts in mice, and treating mice with a γ-secretase inhibitor to inhibit Notch signaling restored tamoxifen sensitivity. Markers of Notch1 activity in tumor tissue correlated with resistance to tamoxifen in breast cancer patients. Similarly, activation of Notch1 signaling promoted acquired resistance to MAPK inhibitors in BRAF(V600E) melanoma cells in culture, and the abundance of Notch1 pathway markers was increased in tumors from a subset of melanoma patients. Thus, Notch1 signaling may be a therapeutic target in some drug-resistant breast cancers and melanomas. Additionally, multiple resistance pathways were activated in melanoma cell lines with intrinsic resistance to MAPK inhibitors, and simultaneous inhibition of these pathways synergistically induced drug sensitivity. These data illustrate the potential for systematic identification of the signaling pathways controlling drug resistance that could inform clinical strategies and drug development for multiple types of cancer. This approach may also be used to advance clinical options in other disease contexts.
Assuntos
Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos , Sistema de Sinalização das MAP Quinases , Melanoma , Proteínas de Neoplasias , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/genética , Melanoma/tratamento farmacológico , Melanoma/genética , Melanoma/metabolismo , Melanoma/patologia , Camundongos , Camundongos Nus , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismoRESUMO
PURPOSE: We previously reported that a fibroblast growth factor (FGF) receptor (FGFR) signaling pathway drives growth of lung cancer cell lines of squamous and large cell histologies. Herein, we explored FGFR dependency in cell lines derived from the tobacco-related malignancy, head and neck squamous cell carcinoma (HNSCC). EXPERIMENTAL DESIGN: FGF and FGFR mRNA and protein expression was assessed in nine HNSCC cell lines. Dependence on secreted FGF2 for cell growth was tested with FP-1039, an FGFR1-Fc fusion protein. FGFR and epidermal growth factor receptor (EGFR) dependence was defined by sensitivity to multiple inhibitors selective for FGFRs or EGFR. RESULTS: FGF2 was expressed in eight of the nine HNSCC cell lines examined. Also, FGFR2 and FGFR3 were frequently expressed, whereas only two lines expressed FGFR1. FP-1039 inhibited growth of HNSCC cell lines expressing FGF2, identifying FGF2 as an autocrine growth factor. FGFR inhibitors selectively reduced in vitro growth and extracellular signal-regulated kinase signaling in three HNSCC cell lines, whereas three distinct lines exhibited responsiveness to both EGFR and FGFR inhibitors. Combinations of these drugs yielded additive growth inhibition. Finally, three cell lines were highly sensitive to EGFR tyrosine kinase inhibitors (TKI) with no contribution from FGFR pathways. CONCLUSIONS: FGFR signaling was dominant or codominant with EGFR in six HNSCC lines, whereas three lines exhibited little or no role for FGFRs and were highly EGFR dependent. Thus, the HNSCC cell lines can be divided into subsets defined by sensitivity to EGFR and FGFR-specific TKIs. FGFR inhibitors may represent novel therapeutics to deploy alone or in combination with EGFR inhibitors in HNSCC.