RESUMO
Nuclear factor κB (NF-κB) plays roles in various diseases. Many inflammatory signals, such as circulating lipopolysaccharides (LPSs), activate NF-κB via specific receptors. Using whole-genome CRISPR-Cas9 screens of LPS-treated cells that express an NF-κB-driven suicide gene, we discovered that the LPS receptor Toll-like receptor 4 (TLR4) is specifically dependent on the oligosaccharyltransferase complex OST-A for N-glycosylation and cell-surface localization. The tool compound NGI-1 inhibits OST complexes in vivo, but the underlying molecular mechanism remained unknown. We did a CRISPR base-editor screen for NGI-1-resistant variants of STT3A, the catalytic subunit of OST-A. These variants, in conjunction with cryoelectron microscopy studies, revealed that NGI-1 binds the catalytic site of STT3A, where it traps a molecule of the donor substrate dolichyl-PP-GlcNAc2-Man9-Glc3, suggesting an uncompetitive inhibition mechanism. Our results provide a rationale for and an initial step toward the development of STT3A-specific inhibitors and illustrate the power of contemporaneous base-editor and structural studies to define drug mechanism of action.
Assuntos
Sistemas CRISPR-Cas , Hexosiltransferases , Lipopolissacarídeos , Proteínas de Membrana , NF-kappa B , Transdução de Sinais , Receptor 4 Toll-Like , Hexosiltransferases/metabolismo , Hexosiltransferases/genética , NF-kappa B/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Humanos , Receptor 4 Toll-Like/metabolismo , Animais , Sistemas CRISPR-Cas/genética , Lipopolissacarídeos/metabolismo , Lipopolissacarídeos/farmacologia , Camundongos , Células HEK293 , Inflamação/metabolismo , Inflamação/genética , Glicosilação , Microscopia Crioeletrônica , Domínio Catalítico , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genéticaRESUMO
PURPOSE: Germline missense variants of unknown significance in cancer-related genes are increasingly being identified with the expanding use of next-generation sequencing. The ataxia telangiectasia-mutated (ATM) gene on chromosome 11 has more than 1,000 germline missense variants of unknown significance and is a tumor suppressor. We aimed to determine if rare germline ATM variants are more frequent in chronic lymphocytic leukemia (CLL) compared with other hematologic malignancies and if they influence the clinical characteristics of CLL. METHODS: We identified 3,128 patients (including 825 patients with CLL) in our hematologic malignancy clinic who had received clinical-grade sequencing of the entire coding region of ATM. We ascertained the comparative frequencies of germline ATM variants in categories of hematologic neoplasms, and, in patients with CLL, we determined whether these variants affected CLL-associated characteristics such as somatic 11q deletion. RESULTS: Rare germline ATM variants are present in 24% of patients with CLL, significantly greater than that in patients with other lymphoid malignancies (16% prevalence), myeloid disease (15%), or no hematologic neoplasm (14%). Patients with CLL with germline ATM variants are younger at diagnosis and twice as likely to have 11q deletion. The ATM variant p.L2307F is present in 3% of patients with CLL, is associated with a three-fold increase in rates of somatic 11q deletion, and is a hypomorph in cell-based assays. CONCLUSION: Germline ATM variants cluster within CLL and affect the phenotype of CLL that develops, implying that some of these variants (such as ATM p.L2307F) have functional significance and should not be ignored. Further studies are needed to determine whether these variants affect the response to therapy or account for some of the inherited risk of CLL.
Assuntos
Proteínas Mutadas de Ataxia Telangiectasia , Leucemia Linfocítica Crônica de Células B , Humanos , Ataxia Telangiectasia , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas de Ciclo Celular/genética , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Mutação , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/uso terapêutico , Proteínas Supressoras de Tumor/genéticaRESUMO
BACKGROUND: Both continuous therapy with acalabrutinib and fixed-duration therapy with venetoclax-obinutuzumab are effective for previously untreated chronic lymphocytic leukaemia. We hypothesised that frontline time-limited, minimal residual disease (MRD)-guided triplet therapy with acalabrutinib, venetoclax, and obinutuzumab would induce deep (ie, more patients with undetectable MRD) and durable remissions. METHODS: In this open-label, single-arm, investigator-sponsored, phase 2 study, patients with chronic lymphocytic leukaemia or small lymphocytic lymphoma were recruited from two academic hospitals in Boston, MA, USA. Eligible patients were aged 18 years or older, with an Eastern Cooperative Oncology Group performance status of 0-2, and were treatment naive. Patients were treated in 28 day cycles. Acalabrutinib monotherapy was given orally at 100 mg twice daily for cycle 1, then combined for six cycles with intravenous obinutuzumab (100 mg on cycle 2 day 1, 900 mg on day 2, 1000 mg on day 8, and 1000 mg on day 15 and on day 1 of cycles 3-7); and from the beginning of cycle 4, oral venetoclax was dosed daily using an accelerated ramp-up from 20 mg on day 1 to 400 mg by day 22 and continued at this dose thereafter. Patients continued on acalabrutinib 100 mg twice daily and venetoclax 400 mg once daily until day 1 of cycle 16 or day 1 of cycle 25. If the patient had undetectable MRD in the bone marrow they were given the option to discontinue therapy at the start of cycle 16 (if also in complete remission) or at the start of cycle 25 (if at least in partial remission). The primary endpoint was complete remission with undetectable MRD in the bone marrow (defined as <1 chronic lymphocytic leukaemia cell per 10 000 leucocytes as measured by four-colour flow cytometry), at cycle 16 day 1. Safety and activity endpoints were assessed in all patients who received at least one dose of any study drug. This study is registered with ClinicalTrials.gov, NCT03580928, and is ongoing. FINDINGS: Between Aug 2, 2018, and May 23, 2019, 37 patients with chronic lymphocytic leukaemia were enrolled and all received at least one dose of any study drug. The median age of patients was 63 years (IQR 57-70), and ten (27%) were female and 27 (73%) were male. Median follow-up was 27·6 months (IQR 25·1-28·2). At cycle 16 day 1, 14 (38% [95% CI 22-55]) of 37 participants had a complete remission with undetectable MRD in the bone marrow. The most common grade 3 or 4 haematological adverse event was neutropenia (16 [43%] of 37 patients). The most common grade 3-4 non-haematological adverse events were hyperglycaemia (three [8%]) and hypophosphataemia (three [8%]). Serious adverse events occurred in nine (24%) patients; the most common was neutropenia in three (8%) patients. There have been no deaths on study. INTERPRETATION: Acalabrutinib, venetoclax, and obinutuzumab is a highly active and well tolerated frontline therapy for chronic lymphocytic leukaemia. Although the primary endpoint of this study was not met, the high proportion of patients who had undetectable MRD in the bone marrow supports further investigation of this regimen, which is being tested against acalabrutinib-venetoclax and chemoimmunotherapy in an ongoing phase 3 study (NCT03836261). FUNDING: AstraZeneca and a Dana-Farber Cancer Institute Collaborative Award.
Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Benzamidas/administração & dosagem , Compostos Bicíclicos Heterocíclicos com Pontes/administração & dosagem , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Pirazinas/administração & dosagem , Sulfonamidas/administração & dosagem , Idoso , Anticorpos Monoclonais Humanizados/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Benzamidas/efeitos adversos , Boston , Compostos Bicíclicos Heterocíclicos com Pontes/efeitos adversos , Esquema de Medicação , Feminino , Humanos , Leucemia Linfocítica Crônica de Células B/diagnóstico , Leucemia Linfocítica Crônica de Células B/mortalidade , Masculino , Pessoa de Meia-Idade , Neoplasia Residual , Intervalo Livre de Progressão , Pirazinas/efeitos adversos , Indução de Remissão , Sulfonamidas/efeitos adversos , Fatores de TempoRESUMO
B cells express 4 phosphatidylinositol 3-kinase (PI3K) isoforms and have a dependence on p110δ for survival. The design of isoform-selective inhibitors is possible, and pharmacologic inhibition of p110δ is toxic to neoplastic chronic lymphocytic leukemia (CLL) cells for both cell-intrinsic and cell-extrinsic reasons. Idelalisib is a first-in-class p110δ inhibitor that exhibits efficacy for the treatment of relapsed CLL irrespective of adverse prognostic features. Duvelisib is a p110γ/δ inhibitor with a similar efficacy and safety profile to idelalisib. Recent data indicate that umbralisib, a p110δ/CK-1ε dual inhibitor, is safe and effective when administered to patients with CLL.
Assuntos
Antineoplásicos , Leucemia Linfocítica Crônica de Células B , Inibidores de Fosfoinositídeo-3 Quinase/uso terapêutico , Antineoplásicos/uso terapêutico , Humanos , Leucemia Linfocítica Crônica de Células B/tratamento farmacológicoRESUMO
Most intracellular proteins lack hydrophobic pockets suitable for altering their function with drug-like small molecules. Recent studies indicate that some undruggable proteins can be targeted by compounds that can degrade them. For example, thalidomide-like drugs (IMiDs) degrade the critical multiple myeloma transcription factors IKZF1 and IKZF3 by recruiting them to the cereblon E3 ubiquitin ligase. Current loss of signal ("down") assays for identifying degraders often exhibit poor signal-to-noise ratios, narrow dynamic ranges, and false positives from compounds that nonspecifically suppress transcription or translation. Here, we describe a gain of signal ("up") assay for degraders. In arrayed chemical screens, we identified novel IMiD-like IKZF1 degraders and Spautin-1, which, unlike the IMiDs, degrades IKZF1 in a cereblon-independent manner. In a pooled CRISPR-Cas9-based screen, we found that CDK2 regulates the abundance of the ASCL1 oncogenic transcription factor. This methodology should facilitate the identification of drugs that directly or indirectly degrade undruggable proteins.
Assuntos
Proteínas Oncogênicas , Proteólise , Proteínas Adaptadoras de Transdução de Sinal/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Benzilaminas , Sistemas CRISPR-Cas , Humanos , Fator de Transcrição Ikaros/metabolismo , Proteínas Oncogênicas/química , Proteínas Oncogênicas/metabolismo , Proteólise/efeitos dos fármacos , Quinazolinas , Talidomida/análise , Talidomida/farmacologia , Fatores de TranscriçãoRESUMO
Despite the propensity for gastric and esophageal adenocarcinomas to select for recurrent missense mutations in TP53, the precise functional consequence of these mutations remains unclear. Here we report that endogenous mRNA and protein levels of mutant p53 were elevated in cell lines and patients with gastric and esophageal cancer. Functional studies showed that mutant p53 was sufficient, but not necessary, for enhancing primary tumor growth in vivo. Unbiased genome-wide transcriptome analysis revealed that hypoxia signaling was induced by mutant p53 in 2 gastric cancer cell lines. Using real-time in vivo imaging, we confirmed that hypoxia reporter activity was elevated during the initiation of mutant p53 gastric cancer xenografts. Unlike HIF co-factor ARNT, HIF1α was required for primary tumor growth in mutant p53 gastric cancer. These findings elucidate the contribution of missense p53 mutations in gastroesophageal malignancy and indicate that hypoxia signaling rather than mutant p53 itself may serve as a therapeutic vulnerability in these deadly set of cancers.
Assuntos
Adenocarcinoma/genética , Neoplasias Esofágicas/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Gástricas/genética , Proteína Supressora de Tumor p53/genética , Adenocarcinoma/patologia , Animais , Translocador Nuclear Receptor Aril Hidrocarboneto/metabolismo , Carcinogênese/genética , Hipóxia Celular/genética , Linhagem Celular Tumoral , Análise Mutacional de DNA , Conjuntos de Dados como Assunto , Mucosa Esofágica/patologia , Neoplasias Esofágicas/patologia , Mucosa Gástrica/patologia , Perfilação da Expressão Gênica , Técnicas de Inativação de Genes , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Microscopia Intravital , Camundongos , Mutação de Sentido Incorreto , Transdução de Sinais/genética , Neoplasias Gástricas/patologia , Transcrição Gênica , Proteína Supressora de Tumor p53/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
PI3 kinase (PI3K) activity is critical for survival of neoplastic B cells in patients with chronic lymphocytic leukemia (CLL). Blockade of PI3K signaling with idelalisib is effective for the treatment of relapsed CLL in combination with the anti-CD20 antibody ofatumumab. In this single-arm, open-label, nonrandomized phase 2 study, we investigated the efficacy and safety of idelalisib with ofatumumab in 27 patients with treatment-naïve CLL in need of therapy. Patients were planned to receive idelalisib for 2 monthly cycles, then idelalisib and ofatumumab for 6 cycles, followed by idelalisib indefinitely. The study was closed early and all patients ceased therapy when an increased rate of death as a result of infection was observed on other first-line idelalisib trials. Median time on therapy was 8.1 months, and median duration of follow-up was 39.7 months. We previously reported high rates of hepatotoxicity in a smaller cohort of patients in this trial; toxicities necessitated therapy discontinuation in 15 patients after a median of 7.7 months. The most frequent grade ≥3 adverse events were transaminitis (52% of patients), neutropenia (33%), and colitis/diarrhea (15%). The best overall response rate (ORR) was 88.9%, including 1 complete response. Median progression-free survival (PFS) was 23 months (95% confidence interval [CI], 18-36 months); 11 patients have not yet required second-line therapy. Idelalisib and ofatumumab demonstrated an unacceptable safety profile in the first-line setting, which resulted in a short PFS despite a high ORR. Future development of PI3K inhibitors for use in treatment-naïve CLL will require novel approaches to mitigate toxicities. This trial was registered at www.clinicaltrials.gov as #NCT02135133.
Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Purinas/administração & dosagem , Quinazolinonas/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Feminino , Humanos , Leucemia Linfocítica Crônica de Células B/complicações , Leucemia Linfocítica Crônica de Células B/mortalidade , Masculino , Pessoa de Meia-Idade , Retirada de Medicamento Baseada em Segurança , Análise de Sobrevida , Resultado do TratamentoRESUMO
INTRODUCTION: Ibrutinib is the first BTK inhibitor to show efficacy in chronic lymphocytic leukemia (CLL) and is also the first BTK inhibitor to which patients have developed resistance. Mutations in BTK and PLCG2 are found in ≈80% of CLL patients with acquired resistance to ibrutinib, but it remains unclear if these mutations are merely associated with disease relapse or directly cause it. Areas covered: Unique properties of both CLL and ibrutinib that complicate attempts to definitively conclude whether BTK/PLCG2 mutations are passengers or drivers of ibrutinib-resistant disease are reviewed. Characteristics of mutations that drive drug resistance are summarized and whether BTK/PLCG2 mutations possess these is discussed. These characteristics include (1) identification in multiple patients with acquired resistance, (2) in vitro validation of drug-resistant properties, (3) mutual exclusivity with one another, (4) increasing frequency over time on drug, and (5) high frequency at the time and site of clinical relapse. Expert commentary: While BTK/PLCG2 mutations have characteristics suggesting that they can drive ibrutinib resistance, this conclusion remains formally unproven until specific inhibition of such mutations is shown to cause regression of ibrutinib-resistant CLL. Data suggest that alternative mechanisms of resistance do exist in some patients.
Assuntos
Tirosina Quinase da Agamaglobulinemia , Resistencia a Medicamentos Antineoplásicos/genética , Leucemia Linfocítica Crônica de Células B , Mutação , Proteínas de Neoplasias , Fosfolipase C gama , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Adenina/análogos & derivados , Tirosina Quinase da Agamaglobulinemia/genética , Tirosina Quinase da Agamaglobulinemia/metabolismo , Animais , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Humanos , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/enzimologia , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/patologia , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Fosfolipase C gama/genética , Fosfolipase C gama/metabolismo , PiperidinasRESUMO
INTRODUCTION: The efficacy of the prototypical phosphatidylinositol-3-kinase (PI3K) inhibitor idelalisib for the treatment of chronic lymphocytic leukemia (CLL) and indolent non-Hodgkin lymphoma (iNHL) has led to development of multiple compounds targeting this pathway. Areas Covered: We review the hypothesized therapeutic mechanisms of PI3K inhibitors, including abrogation of B cell receptor signaling, blockade of microenvironmental pro-survival signals, and enhancement of anti-tumor immunity. We examine toxicities of idelalisib, including bacterial infections (possibly secondary to drug-induced neutropenia), opportunistic infections (possibly attributable to on-target inhibition of T cell function), and organ toxicities such as transaminitis and enterocolitis (possibly autoimmune, secondary to on-target inhibition of p110δ in regulatory T cells). We evaluate PI3K inhibitors that have entered trials for the treatment of lymphoma, focusing on agents with selectivity for PI3Kα and PI3Kδ. Expert Opinion: PI3K inhibitors, particularly those that target p110δ, have robust efficacy in the treatment of CLL and iNHL. However, idelalisib has infectious and autoimmune toxicities that limit its use. Outside of trials, idelalisib should be restricted to CLL patients with progression on ibrutinib or iNHL patients with progression on two prior therapies. Whether newer PI3K inhibitors will demonstrate differentiated toxicity profiles in comparable patient populations while retaining efficacy remains to be seen.
Assuntos
Classe I de Fosfatidilinositol 3-Quinases/antagonistas & inibidores , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Linfoma não Hodgkin/tratamento farmacológico , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacologia , Desenho de Fármacos , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/efeitos adversos , Inibidores Enzimáticos/farmacologia , Humanos , Leucemia Linfocítica Crônica de Células B/patologia , Linfoma não Hodgkin/patologia , Terapia de Alvo Molecular , Purinas/administração & dosagem , Purinas/efeitos adversos , Purinas/farmacologia , Quinazolinonas/administração & dosagem , Quinazolinonas/efeitos adversos , Quinazolinonas/farmacologiaAssuntos
Arritmias Cardíacas/induzido quimicamente , Morte Súbita Cardíaca , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Pirazóis/efeitos adversos , Pirimidinas/efeitos adversos , Adenina/análogos & derivados , Humanos , Masculino , Pessoa de Meia-Idade , Piperidinas , Pirazóis/administração & dosagem , Pirimidinas/administração & dosagemRESUMO
The BCL-2 family of proteins integrates pro- and anti-apoptotic signals within the cell and is responsible for initiation of caspase-dependent apoptosis. Chronic lymphocytic leukemia (CLL) cells are particularly dependent on the anti-apoptotic protein BCL-2 for their survival, making this an attractive therapeutic target in CLL. Several early efforts to create inhibitors of the anti-apoptotic family members faced significant challenges, but eventually, the BCL-2 specific inhibitor venetoclax moved forward in CLL. Overall and complete response rates to venetoclax monotherapy in relapsed, refractory CLL are approximately 80 and 20%, respectively, even in patients with high-risk 17p deletion. Toxicities have been manageable and include neutropenia, diarrhea, and nausea. The risk of tumor lysis syndrome (TLS), seen in early experience with the drug, has been mitigated by the use of appropriate TLS risk assessment, prophylaxis, and management. Future studies of venetoclax will focus on combination approaches, predictive biomarker discovery, and mechanisms of resistance.
Assuntos
Antineoplásicos/uso terapêutico , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Compostos de Anilina/uso terapêutico , Antineoplásicos/efeitos adversos , Compostos Bicíclicos Heterocíclicos com Pontes/efeitos adversos , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Gossipol/química , Gossipol/uso terapêutico , Humanos , Indóis , Neutropenia/etiologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Pirróis/uso terapêutico , Sulfonamidas/efeitos adversos , Sulfonamidas/uso terapêutico , Tionucleotídeos/uso terapêuticoAssuntos
Adenocarcinoma/patologia , Infecções por HIV/complicações , Carcinomatose Meníngea/diagnóstico , Distúrbios da Fala/etiologia , Adenocarcinoma/complicações , Adenocarcinoma/secundário , Idoso , Líquido Cefalorraquidiano/citologia , Diagnóstico Diferencial , Evolução Fatal , Feminino , Humanos , Hiperlipidemias/etiologia , Hipertensão/complicações , Pulmão/diagnóstico por imagem , Pulmão/patologia , Carcinomatose Meníngea/complicações , Carcinomatose Meníngea/secundário , RadiografiaRESUMO
BACKGROUND: Erlotinib is a standard first-line therapy for patients who have metastatic nonsmall cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. The recommended dose of 150 mg daily is the maximum tolerated dose (MTD). Few clinical data are available regarding its efficacy at doses less than the MTD. METHODS: An institutional database was queried for patients with advanced NSCLC who were positive for EGFR L858R mutations or exon 19 deletions and had received treatment with erlotinib. The treatment course, including the erlotinib dose at initiation of treatment, at 4 months into therapy, and at disease progression, was retrospectively studied. Progression-free survival (PFS) was compared between patients who received the MTD (150 mg) and those who received reduced-dose erlotinib (≤100 mg). RESULTS: In total, 198 eligible patients were identified. Thirty-one patients (16%) were initiated on reduced-dose erlotinib; they were older (P = .001) and had lower performance status (P = .01) compared with those who were initiated on erlotinib at the MTD. The response rate to reduced-dose erlotinib was 77%. The median PFS of patients initiated on reduced-dose erlotinib was 9.6 months versus 11.4 months for those initiated at the MTD, a difference that was not statistically significant (hazard ratio, 0.81; 95% confidence interval, 0.54-1.21; P = .30). There was a nonsignificant trend toward higher rates of progression within the central nervous system with reduced-dose erlotinib. CONCLUSIONS: At doses below the MTD, erlotinib treatment results in a high response rate and a prolonged median PFS. Review of the literature indicates that 15 of 30 small-molecule inhibitors that are approved or in late-stage development for cancer therapy have recommended doses below the MTD. When the toxicities of MTD dosing are a concern, an investigation of small-molecule inhibitors at doses below the MTD is warranted. Cancer 2016;122:3456-63. © 2016 American Cancer Society.
RESUMO
Idelalisib is a small-molecule inhibitor of PI3Kδ with demonstrated efficacy for the treatment of relapsed/refractory chronic lymphocytic leukemia (CLL). To evaluate idelalisib as front-line therapy, we enrolled 24 subjects in a phase 2 study consisting of 2 months of idelalisib monotherapy followed by 6 months of combination therapy with idelalisib and the anti-CD20 antibody ofatumumab. After a median follow-up period of 14.7 months, hepatotoxicity was found to be a frequent and often severe adverse event. A total of 19 subjects (79%) experienced either grade ≥1 ALT or AST elevation during the study, and 13 subjects (54%) experienced grade ≥3 transaminitis. The median time to development of transaminitis was 28 days, occurring before ofatumumab introduction. Younger age and mutated immunoglobulin heavy chain status were significant risk factors for the development of hepatotoxicity. Multiple lines of evidence suggest that this hepatotoxicity was immune mediated. A lymphocytic infiltrate was seen on liver biopsy specimens taken from 2 subjects with transaminitis, and levels of the proinflammatory cytokines CCL-3 and CCL-4 were higher in subjects experiencing hepatotoxicity. All cases of transaminitis resolved either by holding the drug, initiating immunosuppressants, or both, and rates of recurrent toxicity were lower in patients taking steroids when idelalisib was reinitiated. A decrease in peripheral blood regulatory T cells was seen in patients experiencing toxicity on therapy, which is consistent with an immune-mediated mechanism. These results suggest that caution should be taken as drugs within this class are developed for CLL, particularly in younger patients who have not received prior disease-specific therapy. This study was registered at www.clinicaltrials.gov as #NCT02135133.
Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Leucemia Linfocítica Crônica de Células B , Purinas , Quinazolinonas , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais Humanizados , Doença Hepática Induzida por Substâncias e Drogas/sangue , Doença Hepática Induzida por Substâncias e Drogas/genética , Doença Hepática Induzida por Substâncias e Drogas/imunologia , Feminino , Hepatite Autoimune/sangue , Hepatite Autoimune/genética , Hepatite Autoimune/imunologia , Humanos , Cadeias Pesadas de Imunoglobulinas/sangue , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Pesadas de Imunoglobulinas/imunologia , Leucemia Linfocítica Crônica de Células B/sangue , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/imunologia , Fígado/imunologia , Fígado/metabolismo , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Mutação , Purinas/administração & dosagem , Purinas/efeitos adversos , Quinazolinonas/administração & dosagem , Quinazolinonas/efeitos adversosRESUMO
Oncogenic, activating mutations in KRAS initiate pancreatic cancer. There are, however, two other Ras family members, Nras and Hras, which can be activated in the presence of oncogenic Kras. The role of these wild-type Ras proteins in cancer remains unclear, as their disruption has been shown to enhance or inhibit tumorigenesis depending upon the context. As pancreatic cancer is critically dependent upon Ras signaling, we tested and now report that loss of Hras increases tumor load and reduces survival in an oncogenic Kras-driven pancreatic adenocarcinoma mouse model. These effects were traced to the earliest stages of pancreatic cancer, suggesting that wild-type Hras may suppress tumor initiation. In normal cells, activated Ras can suppress proliferation through p53-dependent mechanisms. We find that the tumor suppressive effects of Hras are nullified in a homozygous mutant p53 background. As such, loss of wild-type Hras fosters the earliest stages of pancreatic cancer in a p53-dependent manner.
Assuntos
Carcinogênese/genética , Neoplasias Pancreáticas/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteína Supressora de Tumor p53/genética , Animais , Proliferação de Células/genética , Humanos , Camundongos , Camundongos Transgênicos , Mutação , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/terapia , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transdução de Sinais/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
The KRAS gene is commonly mutated in human cancers, rendering the encoded small GTPase constitutively active and oncogenic. This gene has the unusual feature of being enriched for rare codons, which limit protein expression. Here, to determine the effect of the rare codon bias of the KRAS gene on de novo tumorigenesis, we introduced synonymous mutations that converted rare codons into common codons in exon 3 of the Kras gene in mice. Compared with control animals, mice with at least 1 copy of this Kras(ex3op) allele had fewer tumors following carcinogen exposure, and this allele was mutated less often, with weaker oncogenic mutations in these tumors. This reduction in tumorigenesis was attributable to higher expression of the Kras(ex3op) allele, which induced growth arrest when oncogenic and exhibited tumor-suppressive activity when not mutated. Together, our data indicate that the inherent rare codon bias of KRAS plays an integral role in tumorigenesis.
Assuntos
Adenoma/genética , Carcinogênese/genética , Neoplasias Pulmonares/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Adenoma/induzido quimicamente , Adenoma/patologia , Animais , Proliferação de Células , Células Cultivadas , Códon , Feminino , Humanos , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/patologia , Masculino , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Carga Tumoral , UretanaRESUMO
Oncogenic mutations in the small Ras GTPases KRas, HRas, and NRas render the proteins constitutively GTP bound and active, a state that promotes cancer. Ras proteins share ~85% amino acid identity, are activated by and signal through the same proteins, and can exhibit functional redundancy. Nevertheless, manipulating expression or activation of each isoform yields different cellular responses and tumorigenic phenotypes, even when different ras genes are expressed from the same locus. We now report a novel regulatory mechanism hardwired into the very sequence of RAS genes that underlies how such similar proteins impact tumorigenesis differently. Specifically, despite their high sequence similarity, KRAS is poorly translated compared to HRAS due to enrichment in genomically underrepresented or rare codons. Converting rare to common codons increases KRas expression and tumorigenicity to mirror that of HRas. Furthermore, in a genome-wide survey, similar gene pairs with opposing codon bias were identified that not only manifest dichotomous protein expression but also are enriched in key signaling protein classes and pathways. Thus, synonymous nucleotide differences affecting codon usage account for differences between HRas and KRas expression and function and may represent a broader regulation strategy in cell signaling.