RESUMO
The Bruton tyrosine kinase (BTK) inhibitor ibrutinib induces responses in 70% of patients with relapsed and refractory mantle cell lymphoma (MCL). Intrinsic resistance can occur through activation of the nonclassical NF-κB pathway and acquired resistance may involve the BTK C481S mutation. Outcomes after ibrutinib failure are dismal, indicating an unmet medical need. We reasoned that newer heat shock protein 90 (HSP90) inhibitors could overcome ibrutinib resistance by targeting multiple oncogenic pathways in MCL. HSP90 inhibition induced the complete degradation of both BTK and IκB kinase α in MCL lines and CD40-dependent B cells, with downstream loss of MAPK and nonclassical NF-κB signaling. A proteome-wide analysis in MCL lines and an MCL patient-derived xenograft identified a restricted set of targets from HSP90 inhibition that were enriched for factors involved in B-cell receptor and JAK/STAT signaling, the nonclassical NF-κB pathway, cell-cycle regulation, and DNA repair. Finally, multiple HSP90 inhibitors potently killed MCL lines in vitro, and the clinical agent AUY922 was active in vivo against both patient-derived and cell-line xenografts. Together, these findings define the HSP90-dependent proteome in MCL. Considering the disappointing clinical activity of HSP90 inhibitors in other contexts, trials in patients with MCL will be essential for defining the efficacy of and mechanisms of resistance after ibrutinib failure.
Assuntos
Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Isoxazóis/farmacologia , Linfoma de Célula do Manto/tratamento farmacológico , Pirazóis/farmacologia , Pirimidinas/farmacologia , Resorcinóis/farmacologia , Adenina/análogos & derivados , Tirosina Quinase da Agamaglobulinemia , Substituição de Aminoácidos , Animais , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Linfoma de Célula do Manto/genética , Linfoma de Célula do Manto/metabolismo , Linfoma de Célula do Manto/patologia , Camundongos , Mutação de Sentido Incorreto , Piperidinas , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Approximately 10% of B-cell acute lymphoblastic leukemias (B-ALLs) overexpress the cytokine receptor subunit CRLF2, which may confer a poor prognosis. CRLF2 binds its ligand thymic stromal lymphopoietin (TSLP) as a heterodimer with IL7R. Subsets of CRLF2-overexpressing B-ALLs also have a gain-of-function CRLF2 F232C mutation or activating mutations in JAK2. Whether these mutant alleles confer differences in signaling has not been addressed. Through a domain mutation analysis, we demonstrate a distinct dependence on the CRLF2 intracellular tyrosine Y368 in signaling by CRLF2 F232C, but not signaling induced by TSLP or through CRLF2/mutant JAK2. In contrast, CRLF2 signaling in each context is strictly dependent on both the CRLF2 box1 domain and the intracellular tryptophan W286. Using a global quantitative analysis of tyrosine phosphorylation induced by TSLP, we previously identified TSLP-induced phosphorylation of multiple kinases implicated in B-cell receptor signaling, including Lyn, Btk, Hck, Syk, MAPK8, MAPK9, and MAPK10. We now demonstrate that cells dependent on CRLF2/mutant JAK2 have reduced phosphorylation at these targets, suggesting that the kinases promote TSLP-mediated proliferation but serve as negative regulators of CRLF2/mutant JAK2 signaling. Thus, targetable nodes downstream of CRLF2 differ based on the presence or absence of additional mutations in CRLF2 signaling components.
Assuntos
Citocinas/farmacologia , Janus Quinase 2/genética , Janus Quinase 2/metabolismo , Mutação/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Receptores de Citocinas/metabolismo , Animais , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Humanos , Janus Quinase 2/antagonistas & inibidores , Camundongos , Fosforilação , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patologia , Células Precursoras de Linfócitos B/citologia , Células Precursoras de Linfócitos B/metabolismo , RNA Interferente Pequeno/genética , Receptores de Citocinas/genética , Receptores de Interleucina-7/metabolismo , Linfopoietina do Estroma do TimoRESUMO
We investigated the therapeutic potential of JQ1, an inhibitor of the BET class of human bromodomain proteins, in B-cell acute lymphoblastic leukemia (B-ALL). We show that JQ1 potently reduces the viability of B-ALL cell lines with high-risk cytogenetics. Among the most sensitive were lines with rearrangements of CRLF2, which is overexpressed in ~ 10% of B-ALL. CRLF2 heterodimerizes with the IL7 receptor (IL7R) and signals through JAK2, JAK1, and STAT5 to drive proliferation and suppress apoptosis. As previously observed, JQ1 induced the down-regulation of MYC transcription, the loss of BRD4 at the MYC promoter, and the reduced expression of c-Myc target genes. Strikingly, JQ1 also down-regulated IL7R transcription, depleted BRD4 from the IL7R promoter, and reduced JAK2 and STAT5 phosphorylation. Genome-wide expression profiling demonstrated a restricted effect of JQ1 on transcription, with MYC and IL7R being among the most down-regulated genes. Indeed, IL7R was the only cytokine receptor in CRLF2-rearranged B-ALL cells significantly down-regulated by JQ1 treatment. In mice xenografted with primary human CRLF2-rearranged B-ALL, JQ1 suppressed c-Myc expression and STAT5 phosphorylation and significantly prolonged survival. Thus, bromodomain inhibition is a promising therapeutic strategy for B-ALL as well as other conditions dependent on IL7R signaling.
Assuntos
Azepinas/uso terapêutico , Proteínas Nucleares/antagonistas & inibidores , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Receptores de Citocinas/genética , Receptores de Interleucina-7/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Triazóis/uso terapêutico , Animais , Apoptose , Linfócitos B/patologia , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Western Blotting , Proteínas de Ciclo Celular , Linhagem Celular Tumoral , Proliferação de Células , Imunoprecipitação da Cromatina , Citometria de Fluxo , Perfilação da Expressão Gênica , Rearranjo Gênico , Humanos , Janus Quinase 2/genética , Janus Quinase 2/metabolismo , Camundongos , Camundongos Endogâmicos NOD , Análise de Sequência com Séries de Oligonucleotídeos , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas Proto-Oncogênicas c-myc/genética , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Interleucina-7/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Risco , Fator de Transcrição STAT5/genética , Fator de Transcrição STAT5/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: Mobile technology is a novel approach for delivering continuing medical education (CME), with numerous advantages including lower costs and the ability to reach larger numbers than traditional in-person CME workshops. METHODS: From May 2015 to May 2017, we conducted two randomized controlled trials in a phased approach to evaluate the effectiveness of a mobile CME (mCME) approach for two cadres of health professionals in Vietnam. The first randomized controlled trial (RCT) tested the use of an SMS-based educational intervention among Community-Based Physician's Assistants; while feasible and acceptable, this intervention failed to improve medical knowledge among participants. Given the failure of the first RCT, and drawing on qualitative work conducted with participants at the conclusion of the trial, various modifications were employed in the second RCT conducted among HIV specialist physicians in Vietnam. Version 2.0 of the mCME intervention did lead to significant improvement in medical knowledge among intervention participants. Here, we discuss in detail the development of an mCME platform and the experiential "lessons learned" during two phases of implementation. RESULTS: Numerous lessons were learned during implementation, including the importance of: (I) mixed methods approaches; (II) an underlying theoretical framework for behavior change projects; (III) expertise in software programming; (IV) aligning educational content to a well-defined participant population; and (V) engaging and motivating adult learners. We also discuss the critical importance of projects with local ownership and investment that are relevant to local problems. CONCLUSIONS: mHealth approaches for continued healthcare training and education is increasingly relevant in many low-resource settings, the lessons learned here will be valuable to other organizations looking to scale-up similar mHealth-type educational programmes.
RESUMO
BACKGROUND: Community health workers (CHWs) provide critical services to underserved populations in low and middle-income countries, but maintaining CHW's clinical knowledge through formal continuing medical education (CME) activities is challenging and rarely occurs. We tested whether a Short Message Service (SMS)-based mobile CME (mCME) intervention could improve medical knowledge among a cadre of Vietnamese CHWs (Community Based Physician's Assistants-CBPAs) who are the leading providers of primary medical care for rural underserved populations. METHODS: The mCME Project was a three arm randomized controlled trial. Group 1 served as controls while Groups 2 and 3 experienced two models of the mCME intervention. Group 2 (passive model) participants received a daily SMS bullet point, and were required to reply to the text to acknowledge receipt; Group 3 (interactive model) participants received an SMS in multiple choice question format addressing the same thematic area as Group 2, entering an answer (A, B, C or D) in their response. The server provided feedback immediately informing the participant whether the answer was correct. Effectiveness was based on standardized examination scores measured at baseline and endline (six months later). Secondary outcomes included job satisfaction and self-efficacy. RESULTS: 638 CBPAs were enrolled, randomized, and tested at baseline, with 592 returning at endline (93.7%). Baseline scores were similar across all three groups. Over the next six months, participation of Groups 2 and 3 remained high; they responded to >75% of messages. Group 3 participants answered 43% of the daily SMS questions correctly, but their performance did not improve over time. At endline, the CBPAs reported high satisfaction with the mCME intervention, and deemed the SMS messages highly relevant. However, endline exam scores did not increase over baseline, and did not differ between the three groups. Job satisfaction and self-efficacy scores also did not improve. Average times spent on self-study per week did not increase, and the kinds of knowledge resources used by the CBPAs did not differ between the three groups; textbooks, while widely available, were seldom used. CONCLUSIONS: The SMS-based mCME intervention, while feasible and acceptable, did not result in increased medical knowledge. We hypothesize that this was because the intervention failed to stimulate lateral learning. For an intervention of this kind to be effective, it will be essential to find more effective ways to couple SMS as a stimulus to promote increased self-study behaviors. TRIAL REGISTRATION: ClinicalTrials.gov NCT02381743.
Assuntos
Serviços de Saúde Comunitária , Agentes Comunitários de Saúde , Educação Médica Continuada , Assistentes Médicos , Adulto , Educação Médica Continuada/métodos , Avaliação Educacional , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Envio de Mensagens de Texto , Vietnã , Adulto JovemRESUMO
There is a pressing need for methods to define the functional relevance of genetic alterations identified by next-generation sequencing of cancer specimens. We developed new approaches to efficiently construct full-length cDNA libraries from small amounts of total RNA, screen for transforming and resistance phenotypes, and deconvolute by next-generation sequencing. Using this platform, we screened a panel of cDNA libraries from primary specimens and cell lines in cytokine-dependent murine Ba/F3 cells. We demonstrate that cDNA library-based screening can efficiently identify DNA and RNA alterations that confer either cytokine-independent proliferation or resistance to targeted inhibitors, including RNA alterations and intergenic fusions. Using barcoded next-generation sequencing, we simultaneously deconvoluted cytokine-independent clones recovered after transduction of 21 cDNA libraries. This approach identified multiple gain-of-function alleles, including KRAS G12D, NRAS Q61K and an activating splice variant of ERBB2. This approach has broad applicability for identifying transcripts that confer proliferation, resistance and other phenotypes in vitro and potentially in vivo.
Assuntos
Resistencia a Medicamentos Antineoplásicos/genética , Biblioteca Gênica , Testes Genéticos/métodos , Oncogenes , Animais , Linhagem Celular , Proliferação de Células , Cloridrato de Erlotinib , Genes erbB-2 , Predisposição Genética para Doença , Variação Genética , Camundongos , Fenótipo , Isoformas de Proteínas , Quinazolinas/farmacologiaRESUMO
BCL2 suppresses apoptosis by binding the BH3 domain of proapoptotic factors and thereby regulating outer mitochondrial membrane permeabilization. Many tumor types, including B-cell lymphomas and chronic lymphocytic leukemia, are dependent on BCL2 for survival but become resistant to apoptosis after treatment. Here, we identified a direct interaction between the antiapoptotic protein BCL2 and the enzyme PARP1, which suppresses PARP1 enzymatic activity and inhibits PARP1-dependent DNA repair in diffuse large B-cell lymphoma cells. The BH3 mimetic ABT-737 displaced PARP1 from BCL2 in a dose-dependent manner, reestablishing PARP1 activity and DNA repair and promoting nonapoptotic cell death. This form of cell death was unaffected by resistance to single-agent ABT-737 that results from upregulation of antiapoptotic BCL2 family members. On the basis of the ability of BCL2 to suppress PARP1 function, we hypothesized that ectopic BCL2 expression would kill PARP inhibitor-sensitive cells. Strikingly, BCL2 expression reduced the survival of PARP inhibitor-sensitive breast cancer and lung cancer cells by 90% to 100%, and these effects were reversed by ABT-737. Taken together, our findings show that a novel interaction between BCL2 and PARP1 blocks PARP1 enzymatic activity and suppresses PARP1-dependent repair. Targeted disruption of the BCL2-PARP1 interaction therefore may represent a potential therapeutic approach for BCL2-expressing tumors resistant to apoptosis.
Assuntos
Leucemia Linfocítica Crônica de Células B/patologia , Linfoma Difuso de Grandes Células B/patologia , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Animais , Compostos de Bifenilo/farmacologia , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Humanos , Leucemia Linfocítica Crônica de Células B/metabolismo , Linfoma Difuso de Grandes Células B/metabolismo , Metilnitronitrosoguanidina/farmacologia , Camundongos , Nitrofenóis/farmacologia , Piperazinas/farmacologia , Poli(ADP-Ribose) Polimerase-1 , Inibidores de Poli(ADP-Ribose) Polimerases , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Sulfonamidas/farmacologiaRESUMO
Enzymatic inhibitors of Janus kinase 2 (JAK2) are in clinical development for the treatment of myeloproliferative neoplasms (MPNs), B cell acute lymphoblastic leukemia (B-ALL) with rearrangements of the cytokine receptor subunit cytokine receptor-like factor 2 (CRLF2), and other tumors with constitutive JAK2 signaling. In this study, we identify G935R, Y931C, and E864K mutations within the JAK2 kinase domain that confer resistance across a panel of JAK inhibitors, whether present in cis with JAK2 V617F (observed in MPNs) or JAK2 R683G (observed in B-ALL). G935R, Y931C, and E864K do not reduce the sensitivity of JAK2-dependent cells to inhibitors of heat shock protein 90 (HSP90), which promote the degradation of both wild-type and mutant JAK2. HSP90 inhibitors were 100-1,000-fold more potent against CRLF2-rearranged B-ALL cells, which correlated with JAK2 degradation and more extensive blockade of JAK2/STAT5, MAP kinase, and AKT signaling. In addition, the HSP90 inhibitor AUY922 prolonged survival of mice xenografted with primary human CRLF2-rearranged B-ALL further than an enzymatic JAK2 inhibitor. Thus, HSP90 is a promising therapeutic target in JAK2-driven cancers, including those with genetic resistance to JAK enzymatic inhibitors.