RESUMO
Tumor evolution is driven by the progressive acquisition of genetic and epigenetic alterations that enable uncontrolled growth and expansion to neighboring and distal tissues. The study of phylogenetic relationships between cancer cells provides key insights into these processes. Here, we introduced an evolving lineage-tracing system with a single-cell RNA-seq readout into a mouse model of Kras;Trp53(KP)-driven lung adenocarcinoma and tracked tumor evolution from single-transformed cells to metastatic tumors at unprecedented resolution. We found that the loss of the initial, stable alveolar-type2-like state was accompanied by a transient increase in plasticity. This was followed by the adoption of distinct transcriptional programs that enable rapid expansion and, ultimately, clonal sweep of stable subclones capable of metastasizing. Finally, tumors develop through stereotypical evolutionary trajectories, and perturbing additional tumor suppressors accelerates progression by creating novel trajectories. Our study elucidates the hierarchical nature of tumor evolution and, more broadly, enables in-depth studies of tumor progression.
Assuntos
Neoplasias , Animais , Genes ras , Camundongos , Neoplasias/genética , Filogenia , Sequenciamento do ExomaRESUMO
Receptor tyrosine kinase (RTK)-mediated activation of downstream effector pathways such as the RAS GTPase/MAP kinase (MAPK) signaling cascade is thought to occur exclusively from lipid membrane compartments in mammalian cells. Here, we uncover a membraneless, protein granule-based subcellular structure that can organize RTK/RAS/MAPK signaling in cancer. Chimeric (fusion) oncoproteins involving certain RTKs including ALK and RET undergo de novo higher-order assembly into membraneless cytoplasmic protein granules that actively signal. These pathogenic biomolecular condensates locally concentrate the RAS activating complex GRB2/SOS1 and activate RAS in a lipid membrane-independent manner. RTK protein granule formation is critical for oncogenic RAS/MAPK signaling output in these cells. We identify a set of protein granule components and establish structural rules that define the formation of membraneless protein granules by RTK oncoproteins. Our findings reveal membraneless, higher-order cytoplasmic protein assembly as a distinct subcellular platform for organizing oncogenic RTK and RAS signaling.
Assuntos
Condensados Biomoleculares/metabolismo , Grânulos Citoplasmáticos/metabolismo , Neoplasias/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Proteínas ras/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Ativação Enzimática , Proteína Adaptadora GRB2/genética , Proteína Adaptadora GRB2/metabolismo , Células HEK293 , Humanos , Proteína SOS1/metabolismo , Transdução de SinaisRESUMO
Lung cancer, the leading cause of cancer mortality, exhibits heterogeneity that enables adaptability, limits therapeutic success, and remains incompletely understood. Single-cell RNA sequencing (scRNA-seq) of metastatic lung cancer was performed using 49 clinical biopsies obtained from 30 patients before and during targeted therapy. Over 20,000 cancer and tumor microenvironment (TME) single-cell profiles exposed a rich and dynamic tumor ecosystem. scRNA-seq of cancer cells illuminated targetable oncogenes beyond those detected clinically. Cancer cells surviving therapy as residual disease (RD) expressed an alveolar-regenerative cell signature suggesting a therapy-induced primitive cell-state transition, whereas those present at on-therapy progressive disease (PD) upregulated kynurenine, plasminogen, and gap-junction pathways. Active T-lymphocytes and decreased macrophages were present at RD and immunosuppressive cell states characterized PD. Biological features revealed by scRNA-seq were biomarkers of clinical outcomes in independent cohorts. This study highlights how therapy-induced adaptation of the multi-cellular ecosystem of metastatic cancer shapes clinical outcomes.
Assuntos
Neoplasias Pulmonares/genética , Biomarcadores Tumorais/genética , Linhagem Celular , Ecossistema , Humanos , Neoplasias Pulmonares/patologia , Macrófagos/patologia , Análise de Sequência de RNA/métodos , Análise de Célula Única/métodos , Linfócitos T/patologia , Microambiente Tumoral/genéticaRESUMO
Genetic alterations in signaling pathways that control cell-cycle progression, apoptosis, and cell growth are common hallmarks of cancer, but the extent, mechanisms, and co-occurrence of alterations in these pathways differ between individual tumors and tumor types. Using mutations, copy-number changes, mRNA expression, gene fusions and DNA methylation in 9,125 tumors profiled by The Cancer Genome Atlas (TCGA), we analyzed the mechanisms and patterns of somatic alterations in ten canonical pathways: cell cycle, Hippo, Myc, Notch, Nrf2, PI-3-Kinase/Akt, RTK-RAS, TGFß signaling, p53 and ß-catenin/Wnt. We charted the detailed landscape of pathway alterations in 33 cancer types, stratified into 64 subtypes, and identified patterns of co-occurrence and mutual exclusivity. Eighty-nine percent of tumors had at least one driver alteration in these pathways, and 57% percent of tumors had at least one alteration potentially targetable by currently available drugs. Thirty percent of tumors had multiple targetable alterations, indicating opportunities for combination therapy.
Assuntos
Bases de Dados Genéticas , Neoplasias/patologia , Transdução de Sinais/genética , Genes Neoplásicos , Humanos , Neoplasias/genética , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Proteínas Wnt/genética , Proteínas Wnt/metabolismoRESUMO
In this issue, Lv et al.1 explore EGFR-driven epitranscriptomic reprogramming in glioblastoma, revealing the pivotal role of the EGFR-ALKBH5-GCLM axis in ferroptosis protection. Their findings offer mechanistic insight and therapeutic strategies involving novel combination targets to enhance tumor responses.
Assuntos
Neoplasias Encefálicas , Receptores ErbB , Glioblastoma , Humanos , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Receptores ErbB/genética , Receptores ErbB/metabolismo , Glioblastoma/genética , Glioblastoma/metabolismoRESUMO
The Warburg effect, aerobic glycolysis, is a hallmark feature of cancer cells grown in culture. However, the relative roles of glycolysis and respiratory metabolism in supporting in vivo tumor growth and processes such as tumor dissemination and metastatic growth remain poorly understood, particularly on a systems level. Using a CRISPRi mini-library enriched for mitochondrial ribosomal protein and respiratory chain genes in multiple human lung cancer cell lines, we analyzed in vivo metabolic requirements in xenograft tumors grown in distinct anatomic contexts. While knockdown of mitochondrial ribosomal protein and respiratory chain genes (mito-respiratory genes) has little impact on growth in vitro, tumor cells depend heavily on these genes when grown in vivo as either flank or primary orthotopic lung tumor xenografts. In contrast, respiratory function is comparatively dispensable for metastatic tumor growth. RNA-Seq and metabolomics analysis of tumor cells expressing individual sgRNAs against mito-respiratory genes indicate overexpression of glycolytic genes and increased sensitivity of glycolytic inhibition compared to control when grown in vitro, but when grown in vivo as primary tumors these cells down-regulate glycolytic mechanisms. These studies demonstrate that discrete perturbations of mitochondrial respiratory chain function impact in vivo tumor growth in a context-specific manner with differential impacts on primary and metastatic tumors.
Assuntos
Glicólise , Neoplasias Pulmonares , Linhagem Celular Tumoral , Glicólise/genética , Humanos , Neoplasias Pulmonares/patologia , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Proteínas Ribossômicas/metabolismoRESUMO
BACKGROUND: Early recurrence is a major obstacle to prolonged postoperative survival in squamous cell lung carcinoma (SqCLC). The molecular mechanisms underlying early SqCLC recurrence remain unclear, and effective prognostic biomarkers for predicting early recurrence are needed. METHODS: We analyzed primary tumor samples of 20 SqCLC patients using quantitative proteomics to identify differentially-expressed proteins in patients who experienced early versus late disease recurrence. The expression and prognostic significance of DDX56 was evaluated using a SqCLC tumor tissue microarray and further verified using different online databases. We performed in vitro and in vivo experiments to obtain detailed molecular insight into the functional role of DDX56 in SqCLC. RESULTS: We found that DDX56 exhibited increased expression in tumors of patients who experienced early versus late disease recurrence. Increased DDX56 expression in SqCLC tumors was subsequently confirmed as an independent prognostic factor of poor recurrence-free survival in independent SqCLC cohorts. Functionally, DDX56 promotes SqCLC cell growth and migration in vitro, and xenograft tumor progression in vivo. Mechanistically, DDX56 post-transcriptionally promotes expression of multiple Wnt signaling pathway-related genes, including CTNNB1, WNT2B, and represses a subset of miRNAs, including miR-378a-3p, a known suppressor of Wnt signaling. Detailed analysis revealed that DDX56 facilitated degradation of primary miR-378a, leading to down-regulation of mature miR-378a-3p and thus derepression of the target gene WNT2B. CONCLUSION: We identified DDX56 as a novel independent prognostic biomarker that exerts its oncogenic effects through miRNA-mediated post-transcriptional regulation of Wnt signaling genes to promote early SqCLC recurrence. DDX56 may assist in identifying SqCLC patients at increased risk of early recurrence and who could benefit from Wnt signaling-targeted therapies.
Assuntos
Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , RNA Helicases DEAD-box/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , MicroRNAs/genética , Via de Sinalização Wnt , Animais , Biomarcadores Tumorais , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Imuno-Histoquímica , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Masculino , Camundongos , Modelos Biológicos , Prognóstico , Processamento Pós-Transcricional do RNARESUMO
Cancer cells thrive when challenged with proteotoxic stress by inducing components of the protein folding, proteasome, autophagy and unfolded protein response (UPR) pathways. Consequently, specific molecular chaperones have been validated as targets for anti-cancer therapies. For example, inhibition of Hsp70 family proteins (hereafter Hsp70) in rhabdomyosarcoma triggers UPR induction and apoptosis. To define how these cancer cells respond to compromised proteostasis, we compared rhabdomyosarcoma cells that were sensitive (RMS13) or resistant (RMS13-R) to the Hsp70 inhibitor MAL3-101. We discovered that endoplasmic reticulum-associated degradation (ERAD) and autophagy were activated in RMS13-R cells, suggesting that resistant cells overcome Hsp70 ablation by increasing misfolded protein degradation. Indeed, RMS13-R cells degraded ERAD substrates more rapidly than RMS cells and induced the autophagy pathway. Surprisingly, inhibition of the proteasome or ERAD had no effect on RMS13-R cell survival, but silencing of select autophagy components or treatment with autophagy inhibitors restored MAL3-101 sensitivity and led to apoptosis. These data indicate a route through which cancer cells overcome a chaperone-based therapy, define how cells can adapt to Hsp70 inhibition, and demonstrate the value of combined chaperone and autophagy-based therapies.This article has an associated First Person interview with the first author of the paper.
Assuntos
Proteínas de Choque Térmico HSP70/antagonistas & inibidores , Proteostase , Rabdomiossarcoma/fisiopatologia , Apoptose , Autofagia , Linhagem Celular Tumoral , Degradação Associada com o Retículo Endoplasmático , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Humanos , Complexo de Endopeptidases do Proteassoma/metabolismo , Rabdomiossarcoma/genética , Rabdomiossarcoma/metabolismo , Bibliotecas de Moléculas Pequenas/farmacologia , Resposta a Proteínas não DobradasRESUMO
PURPOSE OF REVIEW: Lung cancer remains the leading cause of cancer-related mortality worldwide. Genetic and molecular profiling of non-small cell lung cancer (NSCLC) has led to the discovery of actionable oncogenic driver alterations, which has revolutionized treatment for this disease. This review will move beyond traditional mutational drivers such as EGFR and ALK and will instead focus on emerging targets and the efficacy of new precision therapies. RECENT FINDINGS: Here, we discuss both established and emerging targeted therapy approaches, as well as ongoing challenges for the treatment of NSCLC patients harboring oncogenic alterations of the following types-gene fusions (ROS1, RET, NTRK), receptor tyrosine kinases (MET amplification and exon 14 mutations and EGFR/HER2 exon 20 insertion mutations), and MAPK signaling (SHP2 and altered BRAF and NF1). The treatment of lung cancer is increasingly biomarker-driven, as patients are selected for targeted agents based on the identification of genetic alterations amenable to inhibition. Our ability to further improve patient outcomes with this precision medicine approach will require continued efforts to identify, characterize, and target lesions driving lung cancer tumorigenesis and progression.
Assuntos
Antineoplásicos/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Terapia de Alvo Molecular , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Tirosina Quinases/antagonistas & inibidores , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Medicina de Precisão , PrognósticoRESUMO
Oncogenic activation of protein kinase BRAF drives tumor growth by promoting mitogen-activated protein kinase (MAPK) pathway signaling. Because oncogenic mutations in BRAF occur in â¼2-7% of lung adenocarcinoma (LA), BRAF-mutant LA is the most frequent cause of BRAF-mutant cancer mortality worldwide. Whereas most tumor types harbor predominantly the BRAFV600E-mutant allele, the spectrum of BRAF mutations in LA includes BRAFV600E (â¼60% of cases) and non-V600E mutant alleles (â¼40% of cases) such as BRAFG469A and BRAFG466V The presence of BRAFV600E in LA has prompted clinical trials testing selective BRAF inhibitors such as vemurafenib in BRAFV600E-mutant patients. Despite promising clinical efficacy, both innate and acquired resistance often result from reactivation of MAPK pathway signaling, thus limiting durable responses to the current BRAF inhibitors. Further, the optimal therapeutic strategy to block non-V600E BRAF-mutant LA remains unclear. Here, we report the efficacy of the Raf proto-oncogene serine/threonine protein kinase (RAF) inhibitor, PLX8394, that evades MAPK pathway reactivation in BRAF-mutant LA models. We show that PLX8394 treatment is effective in both BRAFV600E and certain non-V600 LA models, in vitro and in vivo. PLX8394 was effective against treatment-naive BRAF-mutant LAs and those with acquired vemurafenib resistance caused by an alternatively spliced, truncated BRAFV600E that promotes vemurafenib-insensitive MAPK pathway signaling. We further show that acquired PLX8394 resistance occurs via EGFR-mediated RAS-mTOR signaling and is prevented by upfront combination therapy with PLX8394 and either an EGFR or mTOR inhibitor. Our study provides a biological rationale and potential polytherapy strategy to aid the deployment of PLX8394 in lung cancer patients.
Assuntos
Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/enzimologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Mutação/genética , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Proteínas Proto-Oncogênicas B-raf/genética , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Feminino , Técnicas de Silenciamento de Genes , Compostos Heterocíclicos com 2 Anéis/efeitos adversos , Compostos Heterocíclicos com 2 Anéis/farmacocinética , Compostos Heterocíclicos com 2 Anéis/farmacologia , Compostos Heterocíclicos com 2 Anéis/uso terapêutico , Humanos , Neoplasias Pulmonares/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos SCID , Inibidores de Proteínas Quinases/farmacologia , Proto-Oncogene Mas , Sulfonamidas/efeitos adversos , Sulfonamidas/farmacocinética , Sulfonamidas/farmacologia , Sulfonamidas/uso terapêutico , Resultado do TratamentoRESUMO
Cytosolic and organelle-based heat-shock protein (HSP) chaperones ensure proper folding and function of nascent and injured polypeptides to support cell growth. Under conditions of cellular stress, including oncogenic transformation, proteostasis components maintain homeostasis and prevent apoptosis. Although this cancer-relevant function has provided a rationale for therapeutically targeting proteostasis regulators (e.g., HSP90), cancer-subtype dependencies upon particular proteostasis components are relatively undefined. Here, we show that human rhabdomyosarcoma (RMS) cells, but not several other cancer cell types, depend upon heat-shock protein 70 kDA (HSP70) for survival. HSP70-targeted therapy (but not chemotherapeutic agents) promoted apoptosis in RMS cells by triggering an unfolded protein response (UPR) that induced PRKR-like endoplasmic reticulum kinase (PERK)-eukaryotic translation initiation factor α (eIF2α)-CEBP homologous protein (CHOP) signaling and CHOP-mediated cell death. Intriguingly, inhibition of only cytosolic HSP70 induced the UPR, suggesting that the essential activity of HSP70 in RMS cells lies at the endoplasmic reticulum-cytosol interface. We also found that increased CHOP mRNA in clinical specimens was a biomarker for poor outcomes in chemotherapy-treated RMS patients. The data suggest that, like human epidermal growth factor receptor 2 (HER2) amplification in breast cancer, increased CHOP in RMS is a biomarker of decreased response to chemotherapy but enhanced response to targeted therapy. Our findings identify the cytosolic HSP70-UPR axis as an unexpected regulator of RMS pathogenesis, revealing HSP70-targeted therapy as a promising strategy to engage CHOP-mediated apoptosis and improve RMS treatment. Our study highlights the utility of dissecting cancer subtype-specific dependencies on proteostasis networks to uncover unanticipated cancer vulnerabilities.
Assuntos
Proteínas de Choque Térmico HSP70/fisiologia , Rabdomiossarcoma/etiologia , Apoptose , Linhagem Celular Tumoral , Sobrevivência Celular , Proteínas de Choque Térmico HSP70/antagonistas & inibidores , Humanos , Fator de Transcrição PAX3/fisiologia , Rabdomiossarcoma/tratamento farmacológico , Rabdomiossarcoma/patologia , Fator de Transcrição CHOP/fisiologia , Resposta a Proteínas não DobradasRESUMO
High sensitivity imaging tools could provide a more holistic view of target antigen expression to improve the identification of patients who might benefit from cancer immunotherapy. We developed for immunoPET a novel recombinant human IgG1 (termed C4) that potently binds an extracellular epitope on human and mouse PD-L1 and radiolabeled the antibody with zirconium-89. Small animal PET/CT studies showed that 89Zr-C4 detected antigen levels on a patient derived xenograft (PDX) established from a non-small-cell lung cancer (NSCLC) patient before an 8-month response to anti-PD-1 and anti-CTLA4 therapy. Importantly, the concentration of antigen is beneath the detection limit of previously developed anti-PD-L1 radiotracers, including radiolabeled atezolizumab. We also show that 89Zr-C4 can specifically detect antigen in human NSCLC and prostate cancer models endogenously expressing a broad range of PD-L1. 89Zr-C4 detects mouse PD-L1 expression changes in immunocompetent mice, suggesting that endogenous PD-1/2 will not confound human imaging. Lastly, we found that 89Zr-C4 could detect acute changes in tumor expression of PD-L1 due to standard of care chemotherapies. In summary, we present evidence that low levels of PD-L1 in clinically relevant cancer models can be imaged with immunoPET using a novel recombinant human antibody.
Assuntos
Antígeno B7-H1/análise , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Imunoconjugados/química , Imunoglobulina G/química , Neoplasias Pulmonares/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Radioisótopos/química , Zircônio/química , Animais , Linhagem Celular Tumoral , Células HEK293 , Humanos , Pulmão/diagnóstico por imagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Recombinantes/químicaRESUMO
A challenge in precision medicine requires identification of actionable driver mutations. Critical to such effort is the deployment of sensitive and well-validated assays for mutation detection. Although identification of such alterations within the tumor tissue remains the gold standard, many advanced non-small cell lung cancer cases have only limited tissue samples, derived from small biopsies or fine-needle aspirates, available for testing. More recently, noninvasive methods using either circulating tumor cells or tumor DNA (ctDNA) have become an alternative method for identifying molecular biomarkers and screening patients eligible for targeted therapies. In this article, we present a case of a 52-year-old never-smoking male who presented with widely metastatic atypical neuroendocrine tumor to the bones and the brain. Molecular genotyping using DNA harvested from a bone metastasis was unsuccessful due to limited material. Subsequent ctDNA analysis revealed an ALK translocation. The clinical significance of the mutation in this particular cancer type and therapeutic strategies are discussed. KEY POINTS: To our knowledge, this index case represents the first reported ALK translocation identified in an atypical carcinoid tumor.Liquid biopsy such as circulating tumor DNA is a feasible alternative platform for identifying sensitizing genomic alterations.Second-generation ALK inhibitors represent a new paradigm for treating ALK-positive patients with brain metastases.
Assuntos
Neoplasias Encefálicas/secundário , Neoplasias Encefálicas/terapia , Tumores Neuroendócrinos/patologia , Tumores Neuroendócrinos/terapia , Receptores Proteína Tirosina Quinases/genética , Translocação Genética , Quinase do Linfoma Anaplásico , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/genética , Humanos , Biópsia Líquida , Masculino , Pessoa de Meia-Idade , Terapia de Alvo Molecular/métodos , Tumores Neuroendócrinos/diagnóstico por imagem , Tumores Neuroendócrinos/genéticaRESUMO
Human lung adenocarcinomas with activating mutations in EGFR (epidermal growth factor receptor) often respond to treatment with EGFR tyrosine kinase inhibitors (TKIs), but the magnitude of tumour regression is variable and transient. This heterogeneity in treatment response could result from genetic modifiers that regulate the degree to which tumour cells are dependent on mutant EGFR. Through a pooled RNA interference screen, we show that knockdown of FAS and several components of the NF-κB pathway specifically enhanced cell death induced by the EGFR TKI erlotinib in EGFR-mutant lung cancer cells. Activation of NF-κB through overexpression of c-FLIP or IKK (also known as CFLAR and IKBKB, respectively), or silencing of IκB (also known as NFKBIA), rescued EGFR-mutant lung cancer cells from EGFR TKI treatment. Genetic or pharmacologic inhibition of NF-κB enhanced erlotinib-induced apoptosis in erlotinib-sensitive and erlotinib-resistant EGFR-mutant lung cancer models. Increased expression of the NF-κB inhibitor IκB predicted for improved response and survival in EGFR-mutant lung cancer patients treated with EGFR TKI. These data identify NF-κB as a potential companion drug target, together with EGFR, in EGFR-mutant lung cancers and provide insight into the mechanisms by which tumour cells escape from oncogene dependence.
Assuntos
Receptores ErbB/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Proteínas Mutantes/metabolismo , NF-kappa B/metabolismo , Transdução de Sinais , Receptor fas/metabolismo , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Regulação para Baixo , Resistencia a Medicamentos Antineoplásicos , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Cloridrato de Erlotinib , Genes erbB-1/genética , Humanos , Proteínas I-kappa B/metabolismo , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Modelos Biológicos , Proteínas Mutantes/antagonistas & inibidores , Proteínas Mutantes/genética , Mutação/genética , NF-kappa B/antagonistas & inibidores , Quinazolinas/farmacologia , Quinazolinas/uso terapêutico , Interferência de RNA , Transdução de Sinais/efeitos dos fármacos , Receptor fas/antagonistas & inibidoresRESUMO
Oncogenic mutations in the BRAF kinase occur in 6-8% of nonsmall cell lung cancers (NSCLCs), accounting for more than 90,000 deaths annually worldwide. The biological and clinical relevance of these BRAF mutations in NSCLC is incompletely understood. Here we demonstrate that human NSCLC cells with BRAF(V600E), but not other BRAF mutations, initially are sensitive to BRAF-inhibitor treatment. However, these BRAF(V600E) NSCLC cells rapidly acquire resistance to BRAF inhibition through at least one of two discrete molecular mechanisms: (i) loss of full-length BRAF(V600E) coupled with expression of an aberrant form of BRAF(V600E) that retains RAF pathway dependence or (ii) constitutive autocrine EGF receptor (EGFR) signaling driven by c-Jun-mediated EGFR ligand expression. BRAF(V600E) cells with EGFR-driven resistance are characterized by hyperphosphorylated protein kinase AKT, a biomarker we validated in BRAF inhibitor-resistant NSCLC clinical specimens. These data reveal the multifaceted molecular mechanisms by which NSCLCs establish and regulate BRAF oncogene dependence, provide insights into BRAF-EGFR signaling crosstalk, and uncover mechanism-based strategies to optimize clinical responses to BRAF oncogene inhibition.
Assuntos
Comunicação Autócrina/fisiologia , Carcinoma Pulmonar de Células não Pequenas/genética , Resistencia a Medicamentos Antineoplásicos/genética , Receptores ErbB/metabolismo , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Proteínas Proto-Oncogênicas B-raf/genética , Comunicação Autócrina/genética , Sequência de Bases , Humanos , Imuno-Histoquímica , Dados de Sequência Molecular , Mutação de Sentido Incorreto/genética , Proteína Oncogênica v-akt/metabolismo , Fosforilação , Análise de Sequência de RNARESUMO
Mutations leading to activation of proto-oncogenic protein kinases (PKs) are a type of drivers crucial for understanding tumorogenesis and as targets for antitumor drugs. However, bioinformatics tools so far developed to differentiate driver mutations, typically based on conservation considerations, systematically fail to recognize activating mutations in PKs. Here, we present the first comprehensive analysis of the 407 activating mutations described in the literature, which affect 41 PKs. Unexpectedly, we found that these mutations do not associate with conserved positions and do not directly affect ATP binding or catalytic residues. Instead, they cluster around three segments that have been demonstrated to act, in some PKs, as "molecular brakes" of the kinase activity. This finding led us to hypothesize that an auto inhibitory mechanism mediated by such "brakes" is present in all PKs and that the majority of activating mutations act by releasing it. Our results also demonstrate that activating mutations of PKs constitute a distinct group of drivers and that specific bioinformatics tools are needed to identify them in the numerous cancer sequencing projects currently underway. The clustering in three segments should represent the starting point of such tools, a hypothesis that we tested by identifying two somatic mutations in EPHA7 that might be functionally relevant.
Assuntos
Família Multigênica , Mutação de Sentido Incorreto , Proteínas Serina-Treonina Quinases/genética , Domínio Catalítico/genética , Análise por Conglomerados , Biologia Computacional , Humanos , Modelos Moleculares , Neoplasias/genética , Fosforilação , Conformação Proteica , Receptor EphA7/genética , Alinhamento de SequênciaRESUMO
Non-small-cell lung cancer is often diagnosed at the metastatic stage, with median survival of just 1 year. The identification of driver mutations in the epidermal growth factor receptor (EGFR) as the primary oncogenic event in a subset of lung adenocarcinomas led to a model of targeted treatment and genetic profiling of the disease. EGFR tyrosine kinase inhibitors confer remission in 60% of patients, but responses are short-lived. The pre-existing EGFR Thr790Met mutation could be a subclonal driver responsible for these transient responses. Overexpression of AXL and reduced MED12 function are hallmarks of resistance to tyrosine kinase inhibitors in EGFR-mutant non-small-cell lung cancer. Crosstalk between signalling pathways is another mechanism of resistance; therefore, identification of the molecular components involved could lead to the development of combination therapies cotargeting these molecules instead of EGFR tyrosine kinase inhibitor monotherapy. Additionally, novel biomarkers could be identified through deep sequencing analysis of serial rebiopsies before and during treatment.
Assuntos
Biomarcadores Tumorais/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Neoplasias Pulmonares/genética , Medicina de Precisão/métodos , Apoptose/genética , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/terapia , Genes Neoplásicos/genética , Marcadores Genéticos/genética , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/terapia , Mutação/genética , Transdução de Sinais/genéticaRESUMO
OBJECTIVE: Personalized chemotherapy based on predictive biomarkers can maximize efficacy. However, tumor tissue obtained at the time of initial diagnosis will not reflect genetic alterations observed at the time of disease progression. We have examined whether plasma mRNA levels can be a surrogate for tumor levels in predicting chemosensitivity. METHODS: In 150 gastric cancer patients, mRNA levels of BRCA1 and TS were assessed in plasma and paired tumor tissue. The Mann-Whitney U-test was used to compare mRNA expression levels between tumor samples exhibiting in vitro sensitivity or resistance to docetaxel and pemetrexed. All statistical tests were two-sided. RESULTS: There were significant correlations between plasma and tumor mRNA levels of BRCA1 (rho = 0.696, P < 0.001) and TS (rho = 0.620, P < 0.001). BRCA1 levels in plasma (docetaxel-sensitive: 1.25; docetaxel-resistant: 0.50, P < 0.001) and tumor (docetaxel-sensitive: 8.81; docetaxel-resistant: 4.88, P < 0.001) were positively associated with docetaxel sensitivity. TS levels in plasma (pemetrexed-sensitive: 0.90; pemetrexed-resistant: 1.82, P < 0.001) and tumor (pemetrexed-sensitive: 6.56; pemetrexed-resistant: 16.69, P < 0.001) were negatively associated with pemetrexed sensitivity. CONCLUSIONS: Plasma mRNA expression levels mirror those in the tumor and may have a promising role as potential predictive biomarkers for chemotherapy.
Assuntos
Antineoplásicos/uso terapêutico , Biomarcadores Tumorais/genética , Genes BRCA1 , RNA Mensageiro/sangue , Neoplasias Gástricas/tratamento farmacológico , Timidilato Sintase/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Neoplasias Gástricas/sangue , Neoplasias Gástricas/genéticaRESUMO
Activation of the PI3K and epidermal growth factor receptor (EGFR) pathway is able to drive oncogenesis in multiple human cancers, including head and neck squamous cell carcinoma. Targeted agents such as cetuximab and erlotinib are currently used in patients with head and neck squamous cell carcinoma, but, in this disease, the genomic alterations that cause pathway activation and determine response to pharmacologic inhibition remain ill-defined. Here, we present a detailed dissection of the EGFR/PI3K pathway, composed of sequencing of the core pathway components, and high-resolution genomic copy number assessment. Mutations were found in PIK3CA (6%), but no point mutations were observed in other pathway genes such as PTEN and EGFR. In contrast, we observed frequent copy number alterations of genes in the pathway, including PIK3CA, EGFR, protein tyrosine phosphatase receptor S (PTPRS), and RICTOR. In total, activating genetic pathway alterations were identified in 74% of head and neck tumors. Importantly, intragenic microdeletions of the EGFR phosphatase PTPRS were frequent (26%), identifying this gene as a target of 19p13 loss. PTPRS loss promoted EGFR/PI3K pathway activation, modulated resistance to EGFR inhibition, and strongly determined survival in lung cancer patients with activating EGFR mutations. These findings have important implications for our understanding of head and neck cancer tumorigenesis and for the use of targeted agents for this malignancy.
Assuntos
Carcinoma de Células Escamosas/enzimologia , Aberrações Cromossômicas , Cromossomos Humanos Par 19/genética , Receptores ErbB/metabolismo , Neoplasias de Cabeça e Pescoço/enzimologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Tirosina Fosfatases Classe 2 Semelhantes a Receptores/genética , Transdução de Sinais/genética , Western Blotting , Hibridização Genômica Comparativa , Biologia Computacional , Variações do Número de Cópias de DNA , Técnicas de Silenciamento de Genes , Humanos , Mutação/genética , Reação em Cadeia da Polimerase , Interferência de RNA , Análise de Sequência de DNARESUMO
SUMMARY: Beyond lipid membrane compartments, cells including cancer cells utilize various membraneless compartments, often termed biomolecular condensates, to regulate or organize key cellular processes underlying physiologic or pathologic phenotypes. In this commentary, the emergence of biomolecular condensation in cancer biology is highlighted, with a focus on key unanswered questions and with implications for improving the understanding of cancer pathogenesis and developing innovative cancer management strategies.