RESUMO
Lung cancer is the leading cause of cancer mortality worldwide. KRAS oncogenes are responsible for at least a quarter of lung adenocarcinomas, the main subtype of lung cancer. After four decades of intense research, selective inhibitors of KRAS oncoproteins are finally reaching the clinic. Yet, their effect on overall survival is limited due to the rapid appearance of drug resistance, a likely consequence of the high intratumoral heterogeneity characteristic of these tumors. In this study, we have attempted to identify those functional alterations that result from KRAS oncoprotein expression during the earliest stages of tumor development. Such functional changes are likely to be maintained during the entire process of tumor progression regardless of additional co-occurring mutations. Single-cell RNA sequencing analysis of murine alveolar type 2 cells expressing a resident Kras oncogene revealed impairment of the type I interferon pathway, a feature maintained throughout tumor progression. This alteration was also present in advanced murine and human tumors harboring additional mutations in the p53 or LKB1 tumor suppressors. Restoration of type I interferon (IFN) signaling by IFN-ß or constitutive active stimulator of interferon genes (STING) expression had a profound influence on the tumor microenvironment, switching them from immunologically "cold" to immunologically "hot" tumors. Therefore, enhancement of the type I IFN pathway predisposes KRAS mutant lung tumors to immunotherapy treatments, regardless of co-occurring mutations in p53 or LKB1.
Assuntos
Inibidores de Checkpoint Imunológico , Interferon Tipo I , Neoplasias Pulmonares , Mutação , Proteínas Proto-Oncogênicas p21(ras) , Transdução de Sinais , Animais , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Camundongos , Interferon Tipo I/metabolismo , Interferon Tipo I/genética , Humanos , Inibidores de Checkpoint Imunológico/uso terapêutico , Inibidores de Checkpoint Imunológico/farmacologia , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Quinases Proteína-Quinases Ativadas por AMP , Linhagem Celular Tumoral , Microambiente Tumoral/imunologia , Microambiente Tumoral/genética , Proteínas Quinases Ativadas por AMPRESUMO
Due to the limited effectiveness of current treatments, the survival rate of patients with metastatic castration-resistant prostate cancer (mCRPC) is significantly reduced. Consequently, it is imperative to identify novel therapeutic targets for managing these patients. Since the invasive ability of cells is crucial for establishing and maintaining metastasis, the aim of this study was to identify the essential regulators of invasive abilities of mCRPC cells by conducting two independent high-throughput CRISPR/Cas9 screenings. Furthermore, some of the top hits were validated using siRNA technology, with protein arginine methyltransferase 7 (PRMT7) emerging as the most promising candidate. We demonstrated that its inhibition or depletion via genetic or pharmacological approaches significantly reduces invasive, migratory and proliferative abilities of mCRPC cells in vitro. Moreover, we confirmed that PRMT7 ablation reduces cell dissemination in chicken chorioallantoic membrane and mouse xenograft assays. Molecularly, PRMT7 reprograms the expression of several adhesion molecules by methylating various transcription factors, such as FoxK1, resulting in the loss of adhesion from the primary tumor and increased motility of mCRPC cells. Furthermore, PRMT7 higher expression correlates with tumor aggressivity and poor overall survival in prostate cancer patients. Thus, this study demonstrates that PRMT7 is a potential therapeutic target and potential biomarker for mPCa.
Assuntos
Neoplasias de Próstata Resistentes à Castração , Proteína-Arginina N-Metiltransferases , Masculino , Animais , Camundongos , Humanos , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismo , Neoplasias de Próstata Resistentes à Castração/patologia , Sistemas CRISPR-Cas , Genes Essenciais , Detecção Precoce de CâncerRESUMO
CDK2 is a core cell-cycle kinase that phosphorylates many substrates to drive progression through the cell cycle. CDK2 is hyperactivated in multiple cancers and is therefore an attractive therapeutic target. Here, we use several CDK2 inhibitors in clinical development to interrogate CDK2 substrate phosphorylation, cell-cycle progression, and drug adaptation in preclinical models. Whereas CDK1 is known to compensate for loss of CDK2 in Cdk2-/- mice, this is not true of acute inhibition of CDK2. Upon CDK2 inhibition, cells exhibit a rapid loss of substrate phosphorylation that rebounds within several hours. CDK4/6 activity backstops inhibition of CDK2 and sustains the proliferative program by maintaining Rb1 hyperphosphorylation, active E2F transcription, and cyclin A2 expression, enabling re-activation of CDK2 in the presence of drug. Our results augment our understanding of CDK plasticity and indicate that co-inhibition of CDK2 and CDK4/6 may be required to suppress adaptation to CDK2 inhibitors currently under clinical assessment.
Assuntos
Proteínas de Ciclo Celular , Quinases Ciclina-Dependentes , Animais , Camundongos , Quinases Ciclina-Dependentes/metabolismo , Ciclo Celular/fisiologia , Quinase 2 Dependente de Ciclina/genética , Quinase 2 Dependente de Ciclina/metabolismo , Proteínas de Ciclo Celular/metabolismo , Fosforilação , Divisão CelularRESUMO
KRASG12C inhibitors have revolutionized the clinical management of patients with KRASG12C-mutant lung adenocarcinoma. However, patient exposure to these inhibitors leads to the rapid onset of resistance. In this study, we have used genetically engineered mice to compare the therapeutic efficacy and the emergence of tumor resistance between genetic ablation of mutant Kras expression and pharmacological inhibition of oncogenic KRAS activity. Whereas Kras ablation induces massive tumor regression and prevents the appearance of resistant cells in vivo, treatment of KrasG12C/Trp53-driven lung adenocarcinomas with sotorasib, a selective KRASG12C inhibitor, caused a limited antitumor response similar to that observed in the clinic, including the rapid onset of resistance. Unlike in human tumors, we did not observe mutations in components of the RAS-signaling pathways. Instead, sotorasib-resistant tumors displayed amplification of the mutant Kras allele and activation of xenobiotic metabolism pathways, suggesting that reduction of the on-target activity of KRASG12C inhibitors is the main mechanism responsible for the onset of resistance. In sum, our results suggest that resistance to KRAS inhibitors could be prevented by achieving a more robust inhibition of KRAS signaling mimicking the results obtained upon Kras ablation.
Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Animais , Camundongos , Adenocarcinoma de Pulmão/patologia , Neoplasias Pulmonares/patologia , Mutação , Oncogenes , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transdução de SinaisRESUMO
Mutant KRAS is a major driver of oncogenesis in a multitude of cancers but remains a challenging target for classical small molecule drugs, motivating the exploration of alternative approaches. Here, we show that aggregation-prone regions (APRs) in the primary sequence of the oncoprotein constitute intrinsic vulnerabilities that can be exploited to misfold KRAS into protein aggregates. Conveniently, this propensity that is present in wild-type KRAS is increased in the common oncogenic mutations at positions 12 and 13. We show that synthetic peptides (Pept-ins™) derived from two distinct KRAS APRs could induce the misfolding and subsequent loss of function of oncogenic KRAS, both of recombinantly produced protein in solution, during cell-free translation and in cancer cells. The Pept-ins exerted antiproliferative activity against a range of mutant KRAS cell lines and abrogated tumor growth in a syngeneic lung adenocarcinoma mouse model driven by mutant KRAS G12V. These findings provide proof-of-concept that the intrinsic misfolding propensity of the KRAS oncoprotein can be exploited to cause its functional inactivation.
Assuntos
Neoplasias Pulmonares , Proteínas Proto-Oncogênicas p21(ras) , Animais , Camundongos , Linhagem Celular Tumoral , Neoplasias Pulmonares/genética , Mutação , Proteínas Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Dobramento de ProteínaRESUMO
RAF kinases are RAS-activated enzymes that initiate signaling through the MAPK cascade to control cellular proliferation, differentiation, and survival. Here, we describe the structure of the full-length RAF1 protein in complex with HSP90 and CDC37 obtained by cryoelectron microscopy. The reconstruction reveals a RAF1 kinase with an unfolded N-lobe separated from its C-lobe. The hydrophobic core of the N-lobe is trapped in the HSP90 dimer, while CDC37 wraps around the chaperone and interacts with the N- and C-lobes of the kinase. The structure indicates how CDC37 can discriminate between the different members of the RAF family. Our structural analysis also reveals that the folded RAF1 assembles with 14-3-3 dimers, suggesting that after folding RAF1 follows a similar activation as B-RAF. Finally, disruption of the interaction between CDC37 and the DFG segment of RAF1 unveils potential vulnerabilities in attempting the pharmacological degradation of RAF1 for therapeutic purposes.
Assuntos
Proteínas de Ciclo Celular , Chaperoninas , Proteínas de Ciclo Celular/metabolismo , Chaperoninas/química , Microscopia Crioeletrônica , Proteínas de Choque Térmico HSP90/metabolismo , Chaperonas Moleculares/metabolismo , Ligação Proteica , Quinases raf/metabolismoRESUMO
The kinase suppressor of rat sarcoma (RAS) proteins (KSR1 and KSR2) have long been considered as scaffolding proteins required for optimal mitogen-activated protein kinase (MAPK) pathway signalling. However, recent evidence suggests that they play a more complex role within this pathway. Here, we demonstrate that ectopic expression of KSR1 or KSR2 is sufficient to activate the MAPK pathway and to induce cell proliferation in the absence of RAS proteins. In contrast, the ectopic expression of KSR proteins is not sufficient to induce cell proliferation in the absence of either rapidly accelerated fibrosarcoma (RAF) or MAPK-ERK kinase proteins, indicating that they act upstream of RAF. Indeed, KSR1 requires dimerization with at least one member of the RAF family to stimulate proliferation, an event that results in the translocation of the heterodimerized RAF protein to the cell membrane. Mutations in the conserved aspartic acid-phenylalanine-glycine motif of KSR1 that affect ATP binding impair the induction of cell proliferation. We also show that increased expression levels of KSR1 decrease the responsiveness to the KRASG12C inhibitor sotorasib in human cancer cell lines, thus suggesting that increased levels of expression of KSR may make tumour cells less dependent on KRAS oncogenic signalling.
Assuntos
Proteínas Quinases Ativadas por Mitógeno , Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas p21(ras) , Genes ras , Humanos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transdução de SinaisRESUMO
In mammals, the KRAS locus encodes two protein isoforms, KRAS4A and KRAS4B, which differ only in their C terminus via alternative splicing of distinct fourth exons. Previous studies have shown that whereas KRAS expression is essential for mouse development, the KRAS4A isoform is expendable. Here, we have generated a mouse strain that carries a terminator codon in exon 4B that leads to the expression of an unstable KRAS4B154 truncated polypeptide, hence resulting in a bona fide Kras4B-null allele. In contrast, this terminator codon leaves expression of the KRAS4A isoform unaffected. Mice selectively lacking KRAS4B expression developed to term but died perinatally because of hypertrabeculation of the ventricular wall, a defect reminiscent of that observed in embryos lacking the Kras locus. Mouse embryonic fibroblasts (MEFs) obtained from Kras4B-/- embryos proliferated less than did wild-type MEFs, because of limited expression of KRAS4A, a defect that can be compensated for by ectopic expression of this isoform. Introduction of the same terminator codon into a KrasFSFG12V allele allowed expression of an endogenous KRAS4AG12V oncogenic isoform in the absence of KRAS4B. Exposure of Kras+/FSF4AG12V4B- mice to Adeno-FLPo particles induced lung tumors with complete penetrance, albeit with increased latencies as compared with control Kras+/FSFG12V animals. Moreover, a significant percentage of these mice developed proximal metastasis, a feature seldom observed in mice expressing both mutant isoforms. These results illustrate that expression of the KRAS4AG12V mutant isoform is sufficient to induce lung tumors, thus suggesting that selective targeting of the KRAS4BG12V oncoprotein may not have significant therapeutic consequences.
Assuntos
Adenocarcinoma de Pulmão/secundário , Neoplasias Pulmonares/patologia , Proteínas Proto-Oncogênicas p21(ras)/fisiologia , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/metabolismo , Animais , Apoptose , Proliferação de Células , Feminino , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Isoformas de Proteínas , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
RAS gene mutations are the most frequent oncogenic event in lung cancer. They activate multiple RAS-centric signaling networks among them the MAPK, PI3K, and RB pathways. Within the MAPK pathway, ERK1/2 proteins exert a bottleneck function for transmitting mitogenic signals and activating cytoplasmic and nuclear targets. In view of disappointing antitumor activity and toxicity of continuously applied MEK inhibitors in patients with KRAS-mutant lung cancer, research has recently focused on ERK1/2 proteins as therapeutic targets and on ERK inhibitors for their ability to prevent bypass and feedback pathway activation. Here, we show that intermittent application of the novel and selective ATP-competitive ERK1/2 inhibitor LY3214996 exerts single-agent activity in patient-derived xenograft (PDX) models of RAS-mutant lung cancer. Combination treatments were well tolerated and resulted in synergistic (ERKi plus PI3K/mTORi LY3023414) and additive (ERKi plus CDK4/6i abemaciclib) tumor growth inhibition in PDX models. Future clinical trials are required to investigate if intermittent ERK inhibitor-based treatment schedules can overcome toxicities observed with continuous MEK inhibition and-equally important-to identify biomarkers for patient stratification.
Assuntos
Genes ras/efeitos dos fármacos , Neoplasias Pulmonares/tratamento farmacológico , Oncogenes/genética , Inibidores de Proteínas Quinases/uso terapêutico , Linhagem Celular Tumoral , Humanos , Neoplasias Pulmonares/patologia , Inibidores de Proteínas Quinases/farmacologiaAssuntos
Neoplasias Pulmonares/genética , Mutação/genética , Proteínas Proto-Oncogênicas c-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteína Supressora de Tumor p53/genética , Animais , Linhagem Celular Tumoral , Progressão da Doença , Humanos , Neoplasias Pulmonares/patologia , Fosforilação/genética , Proteínas Proto-Oncogênicas/genéticaRESUMO
KRAS mutant lung adenocarcinomas remain intractable for targeted therapies. Genetic interrogation of KRAS downstream effectors, including the MAPK pathway and the interphase CDKs, identified CDK4 and RAF1 as the only targets whose genetic inactivation induces therapeutic responses without causing unacceptable toxicities. Concomitant CDK4 inactivation and RAF1 ablation prevented tumor progression and induced complete regression in 25% of KRAS/p53-driven advanced lung tumors, yet a significant percentage of those tumors that underwent partial regression retained a population of CDK4/RAF1-resistant cells. Characterization of these cells revealed two independent resistance mechanisms implicating hypermethylation of several tumor suppressors and increased PI3K activity. Importantly, these CDK4/RAF1-resistant cells can be pharmacologically controlled. These studies open the door to new therapeutic strategies to treat KRAS mutant lung cancer, including resistant tumors.
Assuntos
Adenocarcinoma de Pulmão/genética , Quinase 4 Dependente de Ciclina/genética , Neoplasias Pulmonares/genética , Proteínas Proto-Oncogênicas c-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteína Supressora de Tumor p53/metabolismo , Adenocarcinoma de Pulmão/tratamento farmacológico , Adenocarcinoma de Pulmão/metabolismo , Adenocarcinoma de Pulmão/patologia , Animais , Antineoplásicos/administração & dosagem , Linhagem Celular Tumoral , Quinase 4 Dependente de Ciclina/metabolismo , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos , Inativação Gênica , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Endogâmicos C57BL , Mutação , Proteínas Proto-Oncogênicas c-raf/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Proteína Supressora de Tumor p53/genéticaRESUMO
Genetically-engineered mouse models (GEMMs) lacking diseased-associated gene(s) globally or in a tissue-specific manner represent an attractive tool with which to assess the efficacy and toxicity of targeted pharmacological inhibitors. Stat3 and Stat5a/b transcription factors have been implicated in several pathophysiological conditions, and pharmacological inhibition of both transcription factors has been proposed to treat certain diseases, such as malignancies. To model combined inhibition of Stat3 and Stat5a/b we have developed a GEMM harboring a flox Stat3-Stat5a/b allele (Stat5/3loxP/loxP mice) and generated mice lacking Stat3 and Stat5a/b in hepatocytes (Stat5/3Δhep/Δhep). Stat5/3Δhep/Δhep mice exhibited a marked reduction of STAT3, STAT5A and STAT5B proteins in the liver and developed steatosis, a phenotype that resembles mice lacking Stat5a/b in hepatocytes. In addition, embryonic deletion of Stat3 and Stat5a/b (Stat5/3Δ/Δ mice) resulted in lethality, similar to Stat3Δ/Δ mice. This data illustrates that Stat5/3loxP/loxP mice are functional and can be used as a valuable tool to model the combined inhibition of Stat3 and Stat5a/b in tumorigenesis and other diseases.
RESUMO
Five-year survival for pancreatic ductal adenocarcinoma (PDAC) patients remains below 7% due to the lack of effective treatments. Here, we report that combined ablation of EGFR and c-RAF expression results in complete regression of a significant percentage of PDAC tumors driven by Kras/Trp53 mutations in genetically engineered mice. Moreover, systemic elimination of these targets induces toxicities that are well tolerated. Response to this targeted therapy correlates with transcriptional profiles that resemble those observed in human PDACs. Finally, inhibition of EGFR and c-RAF expression effectively blocked tumor progression in nine independent patient-derived xenografts carrying KRAS and TP53 mutations. These results open the door to the development of targeted therapies for PDAC patients.
Assuntos
Carcinoma Ductal Pancreático/tratamento farmacológico , Receptores ErbB/metabolismo , Cloridrato de Erlotinib/farmacologia , Gefitinibe/farmacologia , Neoplasias Pancreáticas/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-raf/antagonistas & inibidores , Animais , Apoptose/efeitos dos fármacos , Carcinoma Ductal Pancreático/enzimologia , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação , Neoplasias Pancreáticas/enzimologia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Proteínas Proto-Oncogênicas c-raf/genética , Proteínas Proto-Oncogênicas c-raf/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transdução de Sinais , Carga Tumoral/efeitos dos fármacos , Proteína Supressora de Tumor p53/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
PURPOSE: Myocardial uptake can hamper visualization of lung tumors, atherosclerotic plaques, and inflammatory diseases in 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) studies because it leads to spillover in adjacent structures. Several preparatory pre-imaging protocols (including dietary restrictions and drugs) have been proposed to decrease physiological [18F]FDG uptake by the heart, although their effect on tumor glucose metabolism remains largely unknown. The objective of this study was to assess the effects of a ketogenic diet (as an alternative protocol to fasting) on tumor glucose metabolism assessed by [18F]FDG positron emission tomography (PET) in a mouse model of lung cancer. PROCEDURES: PET scans were performed 60 min after injection of 18.5 MBq of [18F]FDG. PET data were collected for 45 min, and an x-ray computed tomograph (CT) image was acquired after the PET scan. A PET/CT study was obtained for each mouse after fasting and after the ketogenic diet. Quantitative data were obtained from regions of interest in the left ventricular myocardium and lung tumor. RESULTS: Three days on a ketogenic diet decreased mean standard uptake value (SUVmean) in the myocardium (SUVmean 0.95 ± 0.36) more than one night of fasting (SUVmean 1.64 ± 0.93). Tumor uptake did not change under either dietary condition. CONCLUSIONS: These results show that 3 days on high-fat diets prior to [18F]FDG-PET imaging does not change tumor glucose metabolism compared with one night of fasting, although high-fat diets suppress myocardial [18F]FDG uptake better than fasting.
Assuntos
Dieta Cetogênica , Fluordesoxiglucose F18/química , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/dietoterapia , Tomografia por Emissão de Pósitrons , Animais , Glicemia/metabolismo , Modelos Animais de Doenças , Fluordesoxiglucose F18/administração & dosagem , Neoplasias Pulmonares/sangue , Neoplasias Pulmonares/patologia , Camundongos Endogâmicos C57BL , Tomografia Computadorizada por Raios XRESUMO
On the basis of clinical trials using first-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), it became a doctrine that V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (K-RAS) mutations drive resistance to EGFR inhibition in non-small cell lung cancer (NSCLC). Conversely, we provide evidence that EGFR signaling is engaged in K-RAS-driven lung tumorigenesis in humans and in mice. Specifically, genetic mouse models revealed that deletion of Egfr quenches mutant K-RAS activity and transiently reduces tumor growth. However, EGFR inhibition initiates a rapid resistance mechanism involving non-EGFR ERBB family members. This tumor escape mechanism clarifies the disappointing outcome of first-generation TKIs and suggests high therapeutic potential of pan-ERBB inhibitors. On the basis of various experimental models including genetically engineered mouse models, patient-derived and cell line-derived xenografts, and in vitro experiments, we demonstrate that the U.S. Food and Drug Administration-approved pan-ERBB inhibitor afatinib effectively impairs K-RAS-driven lung tumorigenesis. Our data support reconsidering the use of pan-ERBB inhibition in clinical trials to treat K-RAS-mutated NSCLC.
Assuntos
Afatinib/uso terapêutico , Carcinogênese/patologia , Neoplasias Pulmonares/tratamento farmacológico , Proteínas Proto-Oncogênicas p21(ras)/genética , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/patologia , Afatinib/farmacologia , Carcinogênese/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Receptores ErbB/metabolismo , Cloridrato de Erlotinib/farmacologia , Cloridrato de Erlotinib/uso terapêutico , Gefitinibe/farmacologia , Gefitinibe/uso terapêutico , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Mutação/genética , Transdução de Sinais/efeitos dos fármacosRESUMO
A quarter of all solid tumors harbor KRAS oncogenes. Yet, no selective drugs have been approved to treat these malignancies. Genetic interrogation of the MAPK pathway revealed that systemic ablation of MEK or ERK kinases in adult mice prevent tumor development but are unacceptably toxic. Here, we demonstrate that ablation of c-RAF expression in advanced tumors driven by KrasG12V/Trp53 mutations leads to significant tumor regression with no detectable appearance of resistance mechanisms. Tumor regression results from massive apoptosis. Importantly, systemic abrogation of c-RAF expression does not inhibit canonical MAPK signaling, hence, resulting in limited toxicities. These results are of significant relevance for the design of therapeutic strategies to treat K-RAS mutant cancers.
Assuntos
Adenocarcinoma de Pulmão/genética , Genes ras/genética , Mutação/genética , Proteínas Proto-Oncogênicas c-raf/metabolismo , Proteínas ras/genética , Animais , Linhagem Celular Tumoral , Camundongos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas B-raf/genéticaRESUMO
Pancreatic Ductal Adenocarcinoma (PDAC) is a highly lethal malignancy due to its propensity to invade and rapidly metastasize and remains very difficult to manage clinically. One major hindrance towards a better understanding of PDAC is the lack of molecular data sets and models representative of end stage disease. Moreover, it remains unclear how molecularly similar patient-derived xenograft (PDX) models are to the primary tumor from which they were derived. To identify potential molecular drivers in metastatic pancreatic cancer progression, we obtained matched primary tumor, metastases and normal (peripheral blood) samples under a rapid autopsy program and performed whole exome sequencing (WES) on tumor as well as normal samples. PDX models were also generated, sequenced and compared to tumors. Across the matched data sets generated for three patients, there were on average approximately 160 single-nucleotide mutations in each sample. The majority of mutations in each patient were shared among the primary and metastatic samples and, importantly, were largely retained in the xenograft models. Based on the mutation prevalence in the primary and metastatic sites, we proposed possible clonal evolution patterns marked by functional mutations affecting cancer genes such as KRAS, TP53 and SMAD4 that may play an important role in tumor initiation, progression and metastasis. These results add to our understanding of pancreatic tumor biology, and demonstrate that PDX models derived from advanced or end-stage likely closely approximate the genetics of the disease in the clinic and thus represent a biologically and clinically relevant pre-clinical platform that may enable the development of effective targeted therapies for PDAC.
Assuntos
Carcinoma Ductal Pancreático/patologia , Exoma , Neoplasias Pancreáticas/patologia , Mutação Puntual , Idoso , Autopsia , Carcinoma Ductal Pancreático/genética , Progressão da Doença , Feminino , Xenoenxertos , Humanos , Masculino , Neoplasias Pancreáticas/genéticaRESUMO
Myeloid cells lacking STAT3 promote antitumor responses of NK and T cells but it is unknown if this crosstalk affects development of autochthonous tumors. We deleted STAT3 in murine myeloid cells (STAT3Δm) and examined the effect on the development of autochthonous colorectal cancers (CRCs). Formation of Azoxymethane/Dextransulfate (AOM/DSS)-induced CRCs was strongly suppressed in STAT3Δm mice. Gene expression profiling showed strong activation of T cells in the stroma of STAT3Δm CRCs. Moreover, STAT3Δm host mice were better able to control the growth of transplanted MC38 colorectal tumor cells which are known to be killed in a T cell-dependent manner. These data suggest that myeloid cells lacking STAT3 control formation of CRCs mainly via cross activation of T cells. Interestingly, the few CRCs that formed in STAT3Δm mice displayed enhanced stromalization but appeared normal in size indicating that they have acquired ways to escape enhanced tumor surveillance. We found that CRCs in STAT3Δm mice consistently activate STAT3 signaling which is implicated in immune evasion and might be a target to prevent tumor relapse.
RESUMO
PURPOSE: nab-Paclitaxel plus gemcitabine was superior to gemcitabine alone for patients with metastatic pancreatic cancer (MPC) in the phase III MPACT trial. This study evaluated the association of secreted protein acidic and rich in cysteine (SPARC) levels with efficacy as an exploratory endpoint. EXPERIMENTAL DESIGN: Patients with previously untreated MPC (N = 861) received nab-paclitaxel plus gemcitabine or gemcitabine alone. Baseline SPARC level was measured in the tumor stroma and epithelia (archival biopsies) and plasma. Experiments were performed in pancreatic cancer mouse models in which SPARC was intact or deleted. RESULTS: SPARC was measured in the tumor stroma of 256 patients (30%), the tumor epithelia of 301 patients (35%), and plasma of 343 patients (40%). Stroma-evaluable samples were from metastases (71%), from the pancreas (11%), or of unidentifiable origin (insufficient tissue to determine; 17%). For all patients, stromal SPARC level [high (n = 71) vs. low (n = 185)] was not associated with overall survival (OS; HR, 1.019; P = 0.903); multivariate analysis confirmed this lack of association. There was no association between stromal SPARC level and OS in either treatment arm. Neither tumor epithelial SPARC nor plasma SPARC was associated with OS. Results from a SPARC knockout mouse model treated with nab-paclitaxel plus gemcitabine revealed no correlation between SPARC expression and tumor progression or treatment efficacy. CONCLUSIONS: SPARC levels were not associated with efficacy in patients with MPC. This exploratory analysis does not support making treatment decisions regarding nab-paclitaxel plus gemcitabine or gemcitabine alone in MPC based on SPARC expression.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Desoxicitidina/análogos & derivados , Expressão Gênica , Osteonectina/genética , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Albuminas/administração & dosagem , Animais , Biomarcadores , Desoxicitidina/administração & dosagem , Desoxicitidina/uso terapêutico , Modelos Animais de Doenças , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Masculino , Camundongos Knockout , Metástase Neoplásica , Osteonectina/sangue , Osteonectina/metabolismo , Paclitaxel/administração & dosagem , Neoplasias Pancreáticas/mortalidade , Neoplasias Pancreáticas/patologia , Células Estromais/metabolismo , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto , GencitabinaRESUMO
In a personalized treatment designed for a patient with pancreatic cancer resistant to other treatments, the success of Mitomycin C (MMC) has been highlighted. This was revealed in a murine xenograft tumor model encompassing pancreatic adenocarcinoma cells extracted from the patient. The patient was found to exhibit a biallelic inactivation of the PALB2 gene, involved in DNA repair in addition to another mutation in the TSC2 gene that induces susceptibility of the tumor to therapeutic targets of the PI3K-mTOR pathway. The aim of the study was to apply metabolomics to elucidate the modes of action of each therapy, suggesting why MMC was so successful in this patient and why it could be a more popular choice in future pancreatic cancer treatment. The effectiveness of MMC compared to rapamycin (RM), another relevant therapeutic agent has been evaluated through liquid- and gas-chromatography mass spectrometry-based metabolomic analyses of the xenograft tumors. The relative concentrations of many metabolites in the xenograft tumors were found to be increased by MMC relative to other treatments (RM and a combination of both), including a number that are involved in central carbon metabolism (CCM). Metabolic fingerprinting revealed statistically significantly altered pathways including, but not restricted to, the pentose phosphate pathway, glycolysis, TCA cycle, purine metabolism, fatty acid biosynthesis, in addition to many significant lipid and amino acid alterations. Given the genetic background of the patient, it was expected that the combined therapy would be most effective; however, the most effective was MMC alone. It is proposed that the effectiveness of MMC is owed to its direct effect on CCM, a vital region of tumor metabolism.