RESUMEN
In this issue of Molecular Cell, Shui et al.1 use a systems biology approach to unravel a paradoxical role of microRNA in oncogenic KrasG12D regulation of gene and protein expression.
Asunto(s)
MicroARNs , MicroARNs/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Genes ras , MutaciónRESUMEN
Broad-spectrum RAS inhibition has the potential to benefit roughly a quarter of human patients with cancer whose tumours are driven by RAS mutations1,2. RMC-7977 is a highly selective inhibitor of the active GTP-bound forms of KRAS, HRAS and NRAS, with affinity for both mutant and wild-type variants3. More than 90% of cases of human pancreatic ductal adenocarcinoma (PDAC) are driven by activating mutations in KRAS4. Here we assessed the therapeutic potential of RMC-7977 in a comprehensive range of PDAC models. We observed broad and pronounced anti-tumour activity across models following direct RAS inhibition at exposures that were well-tolerated in vivo. Pharmacological analyses revealed divergent responses to RMC-7977 in tumour versus normal tissues. Treated tumours exhibited waves of apoptosis along with sustained proliferative arrest, whereas normal tissues underwent only transient decreases in proliferation, with no evidence of apoptosis. In the autochthonous KPC mouse model, RMC-7977 treatment resulted in a profound extension of survival followed by on-treatment relapse. Analysis of relapsed tumours identified Myc copy number gain as a prevalent candidate resistance mechanism, which could be overcome by combinatorial TEAD inhibition in vitro. Together, these data establish a strong preclinical rationale for the use of broad-spectrum RAS-GTP inhibition in the setting of PDAC and identify a promising candidate combination therapeutic regimen to overcome monotherapy resistance.
Asunto(s)
Antineoplásicos , Carcinoma Ductal Pancreático , Guanosina Trifosfato , Neoplasias Pancreáticas , Proteínas Proto-Oncogénicas p21(ras) , Animales , Femenino , Humanos , Ratones , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Carcinoma Ductal Pancreático/tratamiento farmacológico , Carcinoma Ductal Pancreático/patología , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Variaciones en el Número de Copia de ADN , Resistencia a Antineoplásicos/efectos de los fármacos , Genes myc , Guanosina Trifosfato/metabolismo , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Recurrencia Local de Neoplasia/tratamiento farmacológico , Recurrencia Local de Neoplasia/genética , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/patología , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/antagonistas & inhibidores , Resultado del Tratamiento , Ensayos Antitumor por Modelo de Xenoinjerto , MutaciónRESUMEN
The mitochondrial enzyme glutaminase (GLS) is frequently up-regulated during tumorigenesis and is being evaluated as a target for cancer therapy. GLS catalyzes the hydrolysis of glutamine to glutamate, which then supplies diverse metabolic pathways with carbon and/or nitrogen. Here, we report that SIRT5, a mitochondrial NAD+-dependent lysine deacylase, plays a key role in stabilizing GLS. In transformed cells, SIRT5 regulates glutamine metabolism by desuccinylating GLS and thereby protecting it from ubiquitin-mediated degradation. Moreover, we show that SIRT5 is up-regulated during cellular transformation and supports proliferation and tumorigenesis. Elevated SIRT5 expression in human breast tumors correlates with poor patient prognosis. These findings reveal a mechanism for increasing GLS expression in cancer cells and establish a role for SIRT5 in metabolic reprogramming and mammary tumorigenesis.
RESUMEN
The glutaminase C (GAC) isoform of mitochondrial glutaminase is overexpressed in many cancer cells and therefore represents a potential therapeutic target. Understanding the regulation of GAC activity has been guided by the development of spectroscopic approaches that measure glutaminase activity in real time. Previously, we engineered a GAC protein (GAC(F327W)) in which a tryptophan residue is substituted for phenylalanine in an activation loop to explore the role of this loop in enzyme activity. We showed that the fluorescence emission of Trp-327 is enhanced in response to activator binding, but quenched by inhibitors of the BPTES class that bind to the GAC tetramer and contact the activation loop, thereby constraining it in an inactive conformation. In the present work, we took advantage of a tryptophan substitution at position 471, proximal to the GAC catalytic site, to examine the conformational coupling between the activation loop and the substrate-binding cleft, separated by â¼16 Å. Comparison of glutamine binding in the presence or absence of the BPTES analog CB-839 revealed a reciprocal relationship between the constraints imposed on the activation loop position and the affinity of GAC for substrate. Binding of the inhibitor weakened the affinity of GAC for glutamine, whereas activating anions such as Pi increased this affinity. These results indicate that the conformations of the activation loop and the substrate-binding cleft in GAC are allosterically coupled and that this coupling determines substrate affinity and enzymatic activity and explains the activities of CB-839, which is currently in clinical trials.
Asunto(s)
Bencenoacetamidas/farmacología , Glutaminasa/química , Glutamina/metabolismo , Mitocondrias/enzimología , Tiadiazoles/farmacología , Regulación Alostérica/genética , Sitio Alostérico/genética , Sustitución de Aminoácidos/genética , Animales , Ingeniería Biomédica , Dominio Catalítico/genética , Glutaminasa/metabolismo , Cinética , Ratones , Mitocondrias/química , Modelos Moleculares , Mutación , Isoformas de Proteínas , Estructura Terciaria de Proteína/genética , Proteínas Recombinantes , Sulfuros/farmacologíaRESUMEN
The first step in glutamine catabolism is catalysis by the mitochondrial enzyme glutaminase, with a specific isoform, glutaminase C (GAC), being highly expressed in cancer cells. GAC activation requires the formation of homotetramers, promoted by anionic allosteric activators such as inorganic phosphate. This leads to the proper orientation of a flexible loop proximal to the dimer-dimer interface that is essential for catalysis (i.e. the "activation loop"). A major class of allosteric inhibitors of GAC, with the prototype being bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl)ethyl sulfide (BPTES) and the related molecule CB-839, binds to the activation loop and induces the formation of an inactive tetramer (two inhibitors bound per active tetramer). Here we describe a direct readout for monitoring the dynamics of the activation loop of GAC in response to these allosteric inhibitors, as well as allosteric activators, through the substitution of phenylalanine at position 327 with tryptophan (F327W). The tryptophan fluorescence of the GAC(F327W) mutant undergoes a marked quenching upon the binding of BPTES or CB-839, yielding titration profiles that make it possible to measure the binding affinities of these inhibitors for the enzyme. Allosteric activators like phosphate induce the opposite effect (i.e. fluorescence enhancement). These results describe direct readouts for the binding of the BPTES class of allosteric inhibitors as well as for inorganic phosphate and related activators of GAC, which should facilitate screening for additional modulators of this important metabolic enzyme.
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Bencenoacetamidas/química , Activadores de Enzimas/química , Inhibidores Enzimáticos/química , Glutaminasa/antagonistas & inhibidores , Glutaminasa/química , Proteínas Mitocondriales/agonistas , Proteínas Mitocondriales/antagonistas & inhibidores , Proteínas Mitocondriales/química , Sulfuros/química , Tiadiazoles/química , Regulación Alostérica , Sustitución de Aminoácidos , Animales , Glutaminasa/genética , Ratones , Proteínas Mitocondriales/genética , Mutación Missense , Estructura Secundaria de Proteína , Espectrometría de FluorescenciaRESUMEN
The mitochondrial enzyme glutaminase C (GAC) catalyzes the hydrolysis of glutamine to glutamate plus ammonia, a key step in the metabolism of glutamine by cancer cells. Recently, we discovered a class of allosteric inhibitors of GAC that inhibit cancer cell growth without affecting their normal cellular counterparts, with the lead compound being the bromo-benzophenanthridinone 968. Here, we take advantage of mouse embryonic fibroblasts transformed by oncogenic Dbl, which hyperactivates Rho GTPases, together with (13)C-labeled glutamine and stable-isotope tracing methods, to establish that 968 selectively blocks the enhancement in glutaminolysis necessary for satisfying the glutamine addiction of cancer cells. We then determine how 968 inhibits the catalytic activity of GAC. First, we developed a FRET assay to examine the effects of 968 on the ability of GAC to undergo the dimer-to-tetramer transition necessary for enzyme activation. We next demonstrate how the fluorescence of a reporter group attached to GAC provides a direct read-out of the binding of 968 and related compounds to the enzyme. By combining these fluorescence assays with newly developed GAC mutants trapped in either the monomeric or dimeric state, we show that 968 has the highest affinity for monomeric GAC and that the dose-dependent binding of 968 to GAC monomers directly matches its dose-dependent inhibition of enzyme activity and cellular transformation. Together, these findings highlight the requirement of tetramer formation as the mechanism of GAC activation and shed new light on how a distinct class of allosteric GAC inhibitors impacts the metabolic program of transformed cells.
Asunto(s)
Glutamina/metabolismo , Regulación Alostérica , Sustitución de Aminoácidos , Animales , Benzofenantridinas/farmacología , Transformación Celular Neoplásica/metabolismo , Inhibidores Enzimáticos/farmacología , Transferencia Resonante de Energía de Fluorescencia , Ratones , Modelos Moleculares , Mutagénesis Sitio-Dirigida , Estructura Cuaternaria de Proteína/efectos de los fármacos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Transaminasas/antagonistas & inhibidores , Transaminasas/química , Transaminasas/genéticaRESUMEN
Glutamine-derived carbon becomes available for anabolic biosynthesis in cancer cells via the hydrolysis of glutamine to glutamate, as catalyzed by GAC, a splice variant of kidney-type glutaminase (GLS). Thus, there is significant interest in understanding the regulation of GAC activity, with the suggestion being that higher order oligomerization is required for its activation. We used x-ray crystallography, together with site-directed mutagenesis, to determine the minimal enzymatic unit capable of robust catalytic activity. Mutagenesis of the helical interface between the two pairs of dimers comprising a GAC tetramer yielded a non-active, GAC dimer whose x-ray structure displays a stationary loop ("activation loop") essential for coupling the binding of allosteric activators like inorganic phosphate to catalytic activity. Further mutagenesis that removed constraints on the activation loop yielded a constitutively active dimer, providing clues regarding how the activation loop communicates with the active site, as well as with a peptide segment that serves as a "lid" to close off the active site following substrate binding. Our studies show that the formation of large GAC oligomers is not a pre-requisite for full enzymatic activity. They also offer a mechanism by which the binding of activators like inorganic phosphate enables the activation loop to communicate with the active site to ensure maximal rates of catalysis, and promotes the opening of the lid to achieve optimal product release. Moreover, these findings provide new insights into how other regulatory events might induce GAC activation within cancer cells.
Asunto(s)
Glutaminasa/metabolismo , Glutamina/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/enzimología , Multimerización de Proteína , Animales , Línea Celular Tumoral , Activación Enzimática , Glutaminasa/química , Glutaminasa/genética , Glutamina/química , Glutamina/genética , Humanos , Ratones , Células 3T3 NIH , Proteínas de Neoplasias/química , Proteínas de Neoplasias/genética , Neoplasias/genética , Neoplasias/patología , Estructura Secundaria de ProteínaRESUMEN
To delineate the mechanisms by which the ERK1 and ERK2 mitogen-activated protein kinases support mutant KRAS-driven cancer growth, we determined the ERK-dependent phosphoproteome in KRAS-mutant pancreatic cancer. We determined that ERK1 and ERK2 share near-identical signaling and transforming outputs and that the KRAS-regulated phosphoproteome is driven nearly completely by ERK. We identified 4666 ERK-dependent phosphosites on 2123 proteins, of which 79 and 66%, respectively, were not previously associated with ERK, substantially expanding the depth and breadth of ERK-dependent phosphorylation events and revealing a considerably more complex function for ERK in cancer. We established that ERK controls a highly dynamic and complex phosphoproteome that converges on cyclin-dependent kinase regulation and RAS homolog guanosine triphosphatase function (RHO GTPase). Our findings establish the most comprehensive molecular portrait and mechanisms by which ERK drives KRAS-dependent pancreatic cancer growth.
Asunto(s)
Proteína Quinasa 1 Activada por Mitógenos , Proteína Quinasa 3 Activada por Mitógenos , Neoplasias Pancreáticas , Fosfoproteínas , Proteoma , Proteínas Proto-Oncogénicas p21(ras) , Animales , Humanos , Ratones , Línea Celular Tumoral , Quinasas Ciclina-Dependientes/metabolismo , Quinasas Ciclina-Dependientes/genética , Sistema de Señalización de MAP Quinasas , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Mutación , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Fosfoproteínas/metabolismo , Fosfoproteínas/genética , Fosforilación , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Células HEK293RESUMEN
How the KRAS oncogene drives cancer growth remains poorly understood. Therefore, we established a systemwide portrait of KRAS- and extracellular signal-regulated kinase (ERK)-dependent gene transcription in KRAS-mutant cancer to delineate the molecular mechanisms of growth and of inhibitor resistance. Unexpectedly, our KRAS-dependent gene signature diverges substantially from the frequently cited Hallmark KRAS signaling gene signature, is driven predominantly through the ERK mitogen-activated protein kinase (MAPK) cascade, and accurately reflects KRAS- and ERK-regulated gene transcription in KRAS-mutant cancer patients. Integration with our ERK-regulated phospho- and total proteome highlights ERK deregulation of the anaphase promoting complex/cyclosome (APC/C) and other components of the cell cycle machinery as key processes that drive pancreatic ductal adenocarcinoma (PDAC) growth. Our findings elucidate mechanistically the critical role of ERK in driving KRAS-mutant tumor growth and in resistance to KRAS-ERK MAPK targeted therapies.
Asunto(s)
Carcinoma Ductal Pancreático , Quinasas MAP Reguladas por Señal Extracelular , Regulación Neoplásica de la Expresión Génica , Sistema de Señalización de MAP Quinasas , Mutación , Neoplasias Pancreáticas , Proteínas Proto-Oncogénicas p21(ras) , Transcriptoma , Animales , Humanos , Ratones , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patología , Carcinoma Ductal Pancreático/metabolismo , Línea Celular Tumoral , Resistencia a Antineoplásicos/genética , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Células HEK293RESUMEN
We and others have recently shown that proteins involved in the DNA damage response (DDR) are critical for KRAS-mutant pancreatic ductal adenocarcinoma (PDAC) cell growth in vitro. However, the CRISPR-Cas9 library that enabled us to identify these key proteins had limited representation of DDR-related genes. To further investigate the DDR in this context, we performed a comprehensive, DDR-focused CRISPR-Cas9 loss-of-function screen. This screen identified valosin-containing protein (VCP) as an essential gene in KRAS-mutant PDAC cell lines. We observed that genetic and pharmacologic inhibition of VCP limited cell growth and induced apoptotic death. Addressing the basis for VCP-dependent growth, we first evaluated the contribution of VCP to the DDR and found that loss of VCP resulted in accumulation of DNA double-strand breaks. We next addressed its role in proteostasis and found that loss of VCP caused accumulation of polyubiquitinated proteins. We also found that loss of VCP increased autophagy. Therefore, we reasoned that inhibiting both VCP and autophagy could be an effective combination. Accordingly, we found that VCP inhibition synergized with the autophagy inhibitor chloroquine. We conclude that concurrent targeting of autophagy can enhance the efficacy of VCP inhibitors in KRAS-mutant PDAC.
RESUMEN
Primary/intrinsic and treatment-induced acquired resistance limit the initial response rate to and long-term efficacy of direct inhibitors of the KRASG12C mutant in cancer. To identify potential mechanisms of resistance, we applied a CRISPR/Cas9 loss-of-function screen and observed loss of multiple components of the Hippo tumor suppressor pathway, which acts to suppress YAP1/TAZ-regulated gene transcription. YAP1/TAZ activation impaired the antiproliferative and proapoptotic effects of KRASG12C inhibitor (G12Ci) treatment in KRASG12C-mutant cancer cell lines. Conversely, genetic suppression of YAP1/WWTR1 (TAZ) enhanced G12Ci sensitivity. YAP1/TAZ activity overcame KRAS dependency through two distinct TEAD transcription factor-dependent mechanisms, which phenocopy KRAS effector signaling. First, TEAD stimulated ERK-independent transcription of genes normally regulated by ERK (BIRC5, CDC20, ECT2, FOSL1, and MYC) to promote progression through the cell cycle. Second, TEAD caused activation of PI3K-AKT-mTOR signaling to overcome apoptosis. G12Ci treatment-induced acquired resistance was also caused by YAP1/TAZ-TEAD activation. Accordingly, concurrent treatment with pharmacologic inhibitors of TEAD synergistically enhanced KRASG12C inhibitor antitumor activity in vitro and prolonged tumor suppression in vivo. In summary, these observations reveal YAP1/TAZ-TEAD signaling as a crucial driver of primary and acquired resistance to KRAS inhibition and support the use of TEAD inhibitors to enhance the antitumor efficacy of KRAS-targeted therapies. SIGNIFICANCE: YAP1/TAZ-TEAD activation compensates for loss of KRAS effector signaling, establishing a mechanistic basis for concurrent inhibition of TEAD to enhance the efficacy of KRASG12C-selective inhibitor treatment of KRASG12C-mutant cancers. See related commentary by Johnson and Haigis, p. 4005.
Asunto(s)
Resistencia a Antineoplásicos , Neoplasias , Factores de Transcripción de Dominio TEA , Humanos , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Transactivadores/metabolismo , Proteínas Señalizadoras YAP , Factores de Transcripción de Dominio TEA/antagonistas & inhibidoresRESUMEN
Mutational loss of CDKN2A (encoding p16INK4A) tumor-suppressor function is a key genetic step that complements activation of KRAS in promoting the development and malignant growth of pancreatic ductal adenocarcinoma (PDAC). However, pharmacologic restoration of p16INK4A function with inhibitors of CDK4 and CDK6 (CDK4/6) has shown limited clinical efficacy in PDAC. Here, we found that concurrent treatment with both a CDK4/6 inhibitor (CDK4/6i) and an ERK-MAPK inhibitor (ERKi) synergistically suppresses the growth of PDAC cell lines and organoids by cooperatively blocking CDK4/6i-induced compensatory upregulation of ERK, PI3K, antiapoptotic signaling, and MYC expression. On the basis of these findings, a Phase I clinical trial was initiated to evaluate the ERKi ulixertinib in combination with the CDK4/6i palbociclib in patients with advanced PDAC (NCT03454035). As inhibition of other proteins might also counter CDK4/6i-mediated signaling changes to increase cellular CDK4/6i sensitivity, a CRISPR-Cas9 loss-of-function screen was conducted that revealed a spectrum of functionally diverse genes whose loss enhanced CDK4/6i growth inhibitory activity. These genes were enriched around diverse signaling nodes, including cell-cycle regulatory proteins centered on CDK2 activation, PI3K-AKT-mTOR signaling, SRC family kinases, HDAC proteins, autophagy-activating pathways, chromosome regulation and maintenance, and DNA damage and repair pathways. Novel therapeutic combinations were validated using siRNA and small-molecule inhibitor-based approaches. In addition, genes whose loss imparts a survival advantage were identified (e.g., RB1, PTEN, FBXW7), suggesting possible resistance mechanisms to CDK4/6 inhibition. In summary, this study has identified novel combinations with CDK4/6i that may have clinical benefit to patients with PDAC. SIGNIFICANCE: CRISPR-Cas9 screening and protein activity mapping reveal combinations that increase potency of CDK4/6 inhibitors and overcome drug-induced compensations in pancreatic cancer.
Asunto(s)
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Carcinoma Ductal Pancreático/tratamiento farmacológico , Carcinoma Ductal Pancreático/genética , Línea Celular Tumoral , Quinasa 4 Dependiente de la Ciclina , Quinasa 6 Dependiente de la Ciclina , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Neoplasias PancreáticasRESUMEN
Macroautophagy/autophagy is upregulated in pancreatic ductal adenocarcinoma (PDAC) and PDAC growth is reliant on autophagy. However, autophagy inhibitors as monotherapy have shown limited clinical efficacy. To identify targets that sensitize PDAC cells to autophagy inhibition, we performed a CRISPR-Cas9 genetic loss-of-function screen in cells treated with the lysosomal inhibitor chloroquine (CQ) and identified IGF1R as a sensitizer. IGF1R inhibition increases autophagic flux and sensitivity to CQ-mediated growth suppression both in vitro and in vivo. Importantly, sensitization is further enhanced with the concurrent inhibition of MAPK1/ERK2 (mitogen-activated protein kinase 1)-MAPK3/ERK1. IGF1R and MAPK/ERK inhibition converge on suppression of glycolysis. In summary, IGF1R and MAPK/ERK signaling promotes resistance to CQ/HCQ in PDAC, and their dual inhibition increases sensitivity to autophagy inhibitors.
Asunto(s)
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Autofagia , Carcinoma Ductal Pancreático/tratamiento farmacológico , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Línea Celular Tumoral , Cloroquina/farmacología , Cloroquina/uso terapéutico , Humanos , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Receptor IGF Tipo 1/uso terapéutico , Neoplasias PancreáticasRESUMEN
The aggressive nature of pancreatic ductal adenocarcinoma (PDAC) mandates the development of improved therapies. As KRAS mutations are found in 95% of PDAC and are critical for tumor maintenance, one promising strategy involves exploiting KRAS-dependent metabolic perturbations. The macrometabolic process of autophagy is upregulated in KRAS-mutant PDAC, and PDAC growth is reliant on autophagy. However, inhibition of autophagy as monotherapy using the lysosomal inhibitor hydroxychloroquine (HCQ) has shown limited clinical efficacy. To identify strategies that can improve PDAC sensitivity to HCQ, we applied a CRISPR-Cas9 loss-of-function screen and found that a top sensitizer was the receptor tyrosine kinase (RTK) insulin-like growth factor 1 receptor (IGF1R). Additionally, reverse phase protein array pathway activation mapping profiled the signaling pathways altered by chloroquine (CQ) treatment. Activating phosphorylation of RTKs, including IGF1R, was a common compensatory increase in response to CQ. Inhibition of IGF1R increased autophagic flux and sensitivity to CQ-mediated growth suppression both in vitro and in vivo. Cotargeting both IGF1R and pathways that antagonize autophagy, such as ERK-MAPK axis, was strongly synergistic. IGF1R and ERK inhibition converged on suppression of glycolysis, leading to enhanced dependence on autophagy. Accordingly, concurrent inhibition of IGF1R, ERK, and autophagy induced cytotoxicity in PDAC cell lines and decreased viability in human PDAC organoids. In conclusion, targeting IGF1R together with ERK enhances the effectiveness of autophagy inhibitors in PDAC. SIGNIFICANCE: Compensatory upregulation of IGF1R and ERK-MAPK signaling limits the efficacy of autophagy inhibitors chloroquine and hydroxychloroquine, and their concurrent inhibition synergistically increases autophagy dependence and chloroquine sensitivity in pancreatic ductal adenocarcinoma.
Asunto(s)
Autofagia/fisiología , Carcinoma Ductal Pancreático/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Sistema de Señalización de MAP Quinasas/fisiología , Neoplasias Pancreáticas/metabolismo , Receptor IGF Tipo 1/metabolismo , Animales , Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Carcinoma Ductal Pancreático/tratamiento farmacológico , Carcinoma Ductal Pancreático/patología , Línea Celular Tumoral , Sinergismo Farmacológico , Inhibidores Enzimáticos/farmacología , Quinasas MAP Reguladas por Señal Extracelular/antagonistas & inhibidores , Glucólisis/efectos de los fármacos , Células HEK293 , Humanos , Hidroxicloroquina/farmacología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Masculino , Ratones Endogámicos C57BL , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/patología , Fosforilación/efectos de los fármacos , Pirazoles/farmacología , Receptor IGF Tipo 1/antagonistas & inhibidores , Triazinas/farmacología , Ensayos Antitumor por Modelo de Xenoinjerto/métodosRESUMEN
We apply genetic screens to delineate modulators of KRAS mutant pancreatic ductal adenocarcinoma (PDAC) sensitivity to ERK inhibitor treatment, and we identify components of the ATR-CHK1 DNA damage repair (DDR) pathway. Pharmacologic inhibition of CHK1 alone causes apoptotic growth suppression of both PDAC cell lines and organoids, which correlates with loss of MYC expression. CHK1 inhibition also activates ERK and AMPK and increases autophagy, providing a mechanistic basis for increased efficacy of concurrent CHK1 and ERK inhibition and/or autophagy inhibition with chloroquine. To assess how CHK1 inhibition-induced ERK activation promotes PDAC survival, we perform a CRISPR-Cas9 loss-of-function screen targeting direct/indirect ERK substrates and identify RIF1. A key component of non-homologous end joining repair, RIF1 suppression sensitizes PDAC cells to CHK1 inhibition-mediated apoptotic growth suppression. Furthermore, ERK inhibition alone decreases RIF1 expression and phenocopies RIF1 depletion. We conclude that concurrent DDR suppression enhances the efficacy of ERK and/or autophagy inhibitors in KRAS mutant PDAC.
Asunto(s)
Carcinoma Ductal Pancreático/tratamiento farmacológico , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/antagonistas & inhibidores , Daño del ADN , Mutación , Neoplasias Pancreáticas/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas p21(ras)/genética , Animales , Apoptosis , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patología , Proliferación Celular , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/genética , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/metabolismo , Humanos , Ratones , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patología , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
To identify therapeutic targets for KRAS mutant pancreatic cancer, we conduct a druggable genome small interfering RNA (siRNA) screen and determine that suppression of BCAR1 sensitizes pancreatic cancer cells to ERK inhibition. Integrative analysis of genome-scale CRISPR-Cas9 screens also identify BCAR1 as a top synthetic lethal interactor with mutant KRAS. BCAR1 encodes the SRC substrate p130Cas. We determine that SRC-inhibitor-mediated suppression of p130Cas phosphorylation impairs MYC transcription through a DOCK1-RAC1-ß-catenin-dependent mechanism. Additionally, genetic suppression of TUBB3, encoding the ßIII-tubulin subunit of microtubules, or pharmacological inhibition of microtubule function decreases levels of MYC protein in a calpain-dependent manner and potently sensitizes pancreatic cancer cells to ERK inhibition. Accordingly, the combination of a dual SRC/tubulin inhibitor with an ERK inhibitor cooperates to reduce MYC protein and synergistically suppress the growth of KRAS mutant pancreatic cancer. Thus, we demonstrate that mechanistically diverse combinations with ERK inhibition suppress MYC to impair pancreatic cancer proliferation.
Asunto(s)
Proteína Sustrato Asociada a CrK/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/antagonistas & inhibidores , Microtúbulos/metabolismo , Neoplasias Pancreáticas/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-myc/metabolismo , Acetamidas/farmacología , Apoptosis/efectos de los fármacos , Apoptosis/genética , Calpaína/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Proliferación Celular/genética , Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/genética , Sinergismo Farmacológico , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Semivida , Humanos , Microtúbulos/efectos de los fármacos , Morfolinas/farmacología , Mutación/genética , Organoides/efectos de los fármacos , Organoides/metabolismo , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Proteínas Proto-Oncogénicas p21(ras)/genética , Piridinas/farmacología , Transcripción Genética/efectos de los fármacos , Tubulina (Proteína)/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto , Familia-src Quinasas/antagonistas & inhibidores , Familia-src Quinasas/metabolismoRESUMEN
Oncogenic RAS proteins, which are mutated in approximately 24% of all human cancers, have earned a well-deserved reputation as being "undruggable." However, several studies have challenged that reputation. With the first small molecules that directly target one oncogenic RAS mutant (G12C) undergoing clinical evaluation, there have been substantial advances in finding anti-RAS therapeutic strategies. Furthermore, new insights have come from the growing appreciation that neither all RAS proteins (HRAS, NRAS, and KRAS4A/KRAS4B) nor all oncogenic RAS mutations (such as at residues Gly12, Gly13, and Gln61) have the same impact on RAS signaling and function. The role of the nonmutated, wild-type RAS proteins in the context of mutant RAS is increasingly considered to be targetable, with reports of strategies that directly disrupt either the RAS interaction with activating guanine nucleotide exchange factors (GEFs) or receptor tyrosine kinase-mediated and GEF-dependent RAS activation (such as by targeting the scaffolding phosphatase SHP2). Last, the development of agents that target downstream effectors of RAS signaling has advanced substantially. In this review, we highlight some important trends in the targeting of RAS proteins in cancer.
Asunto(s)
Mutación , Proteínas de Neoplasias/metabolismo , Neoplasias/enzimología , Neoplasias/terapia , Transducción de Señal , Proteínas ras/metabolismo , Animales , Humanos , Proteínas de Neoplasias/genética , Neoplasias/genética , Proteínas ras/genéticaRESUMEN
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMEN
Pancreatic ductal adenocarcinoma (PDAC) is characterized by KRAS- and autophagy-dependent tumorigenic growth, but the role of KRAS in supporting autophagy has not been established. We show that, to our surprise, suppression of KRAS increased autophagic flux, as did pharmacological inhibition of its effector ERK MAPK. Furthermore, we demonstrate that either KRAS suppression or ERK inhibition decreased both glycolytic and mitochondrial functions. We speculated that ERK inhibition might thus enhance PDAC dependence on autophagy, in part by impairing other KRAS- or ERK-driven metabolic processes. Accordingly, we found that the autophagy inhibitor chloroquine and genetic or pharmacologic inhibition of specific autophagy regulators synergistically enhanced the ability of ERK inhibitors to mediate antitumor activity in KRAS-driven PDAC. We conclude that combinations of pharmacologic inhibitors that concurrently block both ERK MAPK and autophagic processes that are upregulated in response to ERK inhibition may be effective treatments for PDAC.