RESUMO
TP53-mutant blood cancers remain a clinical challenge. BH3-mimetic drugs inhibit BCL-2 pro-survival proteins, inducing cancer cell apoptosis. Despite acting downstream of p53, functional p53 is required for maximal cancer cell killing by BH3-mimetics through an unknown mechanism. Here, we report p53 is activated following BH3-mimetic induced mitochondrial outer membrane permeabilization, leading to BH3-only protein induction and thereby potentiating the pro-apoptotic signal. TP53-deficient lymphomas lack this feedforward loop, providing opportunities for survival and disease relapse after BH3-mimetic treatment. The therapeutic barrier imposed by defects in TP53 can be overcome by direct activation of the cGAS/STING pathway, which promotes apoptosis of blood cancer cells through p53-independent BH3-only protein upregulation. Combining clinically relevant STING agonists with BH3-mimetic drugs efficiently kills TRP53/TP53-mutant mouse B lymphoma, human NK/T lymphoma, and acute myeloid leukemia cells. This represents a promising therapy regime that can be fast-tracked to tackle TP53-mutant blood cancers in the clinic.
Assuntos
Apoptose , Proteínas de Membrana , Proteína Supressora de Tumor p53 , Proteína Supressora de Tumor p53/genética , Humanos , Animais , Camundongos , Proteínas de Membrana/genética , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Mutação , Neoplasias Hematológicas/tratamento farmacológico , Neoplasias Hematológicas/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Fragmentos de Peptídeos/farmacologia , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Transdução de Sinais/efeitos dos fármacos , Proteínas Proto-Oncogênicas/genéticaRESUMO
Mutations in the tumor suppressor TP53 cause cancer and impart poor chemotherapeutic responses, reportedly through loss-of-function, dominant-negative effects and gain-of-function (GOF) activities. The relative contributions of these attributes is unknown. We found that removal of 12 different TP53 mutants with reported GOFs by CRISPR/Cas9 did not impact proliferation and response to chemotherapeutics of 15 human cancer cell lines and colon cancer-derived organoids in culture. Moreover, removal of mutant TP53/TRP53 did not impair growth or metastasis of human cancers in immune-deficient mice or growth of murine cancers in immune-competent mice. DepMap mining revealed that removal of 158 different TP53 mutants had no impact on the growth of 391 human cancer cell lines. In contrast, CRISPR-mediated restoration of wild-type TP53 extinguished the growth of human cancer cells in vitro. These findings demonstrate that LOF but not GOF effects of mutant TP53/TRP53 are critical to sustain expansion of many tumor types. SIGNIFICANCE: This study provides evidence that removal of mutant TP53, thereby deleting its reported GOF activities, does not impact the survival, proliferation, metastasis, or chemotherapy responses of cancer cells. Thus, approaches that abrogate expression of mutant TP53 or target its reported GOF activities are unlikely to exert therapeutic impact in cancer. See related commentary by Lane, p. 211 . This article is featured in Selected Articles from This Issue, p. 201.
Assuntos
Neoplasias do Colo , Proteína Supressora de Tumor p53 , Humanos , Camundongos , Animais , Linhagem Celular Tumoral , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Mutação , Neoplasias do Colo/genética , Proliferação de CélulasRESUMO
Whole-genome screens using CRISPR technologies are powerful tools to identify novel tumour suppressors as well as factors that impact responses of malignant cells to anti-cancer agents. Applying this methodology to lymphoma cells, we conducted a genome-wide screen to identify novel inhibitors of tumour expansion that are induced by the tumour suppressor TRP53. We discovered that the absence of Arrestin domain containing 3 (ARRDC3) increases the survival and long-term competitiveness of MYC-driven lymphoma cells when treated with anti-cancer agents that activate TRP53. Deleting Arrdc3 in mice caused perinatal lethality due to various developmental abnormalities, including cardiac defects. Notably, the absence of ARRDC3 markedly accelerated MYC-driven lymphoma development. Thus, ARRDC3 is a new mediator of TRP53-mediated suppression of tumour expansion, and this discovery may open new avenues to harness this process for cancer therapy.
Assuntos
Linfoma , Neoplasias , Animais , Camundongos , Arrestinas/genética , Arrestinas/metabolismo , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Neoplasias/genéticaRESUMO
The BH3-mimetic drug Venetoclax, a specific inhibitor of anti-apoptotic BCL-2, has had clinical success for the treatment of chronic lymphocytic leukaemia and acute myeloid leukaemia. Attention has now shifted towards related pro-survival BCL-2 family members, hypothesising that new BH3-mimetic drugs targeting these proteins may emulate the success of Venetoclax. BH3-mimetics targeting pro-survival MCL-1 or BCL-XL have entered clinical trials, but managing on-target toxicities is challenging. While increasing evidence suggests BFL-1/A1 is a resistance factor for diverse chemotherapeutic agents and BH3-mimetic drugs in haematological malignancies, few studies have explored the role of BCL-W in the development, expansion, and therapeutic responses of cancer. Previously, we found that BCL-W was not required for the ongoing survival and growth of various established human Burkitt lymphoma and diffuse large B cell lymphoma cell lines. However, questions remained about whether BCL-W impacts lymphoma development. Here, we show that BCL-W appears dispensable for MYC-driven lymphomagenesis, and such tumours arising in the absence of BCL-W show no compensatory changes to BCL-2 family member expression, nor altered sensitivity to BH3-mimetic drugs. These results demonstrate that BCL-W does not play a major role in the development of MYC-driven lymphoma or the responses of these tumours to anti-cancer agents.
Assuntos
Antineoplásicos , Linfoma de Burkitt , Linfoma Difuso de Grandes Células B , Humanos , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose , Linfoma de Burkitt/tratamento farmacológico , Linfoma de Burkitt/genética , Linfoma de Burkitt/patologia , Linhagem Celular Tumoral , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismoRESUMO
Elevated Ras signalling is highly prevalent in human cancer; however, targeting Ras-driven cancers with Ras pathway inhibitors often leads to undesirable side effects and to drug resistance. Thus, identifying compounds that synergise with Ras pathway inhibitors would enable lower doses of the Ras pathway inhibitors to be used and also decrease the acquisition of drug resistance. Here, in a specialised chemical screen using a Drosophila model of Ras-driven cancer, we have identified compounds that reduce tumour size by synergising with sub-therapeutic doses of the Ras pathway inhibitor trametinib, which targets MEK, the mitogen-activated protein kinase kinase, in this pathway. Analysis of one of the hits, ritanserin, and related compounds revealed that diacyl glycerol kinase α (DGKα, Dgk in Drosophila) was the critical target required for synergism with trametinib. Human epithelial cells harbouring the H-RAS oncogene and knockdown of the cell polarity gene SCRIB were also sensitive to treatment with trametinib and DGKα inhibitors. Mechanistically, DGKα inhibition synergises with trametinib by increasing the P38 stress-response signalling pathway in H-RASG12V SCRIBRNAi cells, which could lead to cell quiescence. Our results reveal that targeting Ras-driven human cancers with Ras pathway and DGKα inhibitors should be an effective combination drug therapy.
Assuntos
Antineoplásicos , Neoplasias , Animais , Humanos , Quinases de Proteína Quinase Ativadas por Mitógeno , Drosophila , Linhagem Celular Tumoral , Transdução de Sinais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Neoplasias/tratamento farmacológicoRESUMO
BH3-mimetic drugs are an anti-cancer therapy that can induce apoptosis in malignant cells by directly binding and inhibiting pro-survival proteins of the BCL-2 family. The BH3-mimetic drug venetoclax, which targets BCL-2, has been approved for the treatment of chronic lymphocytic leukaemia and acute myeloid leukaemia by regulatory authorities worldwide. However, while most patients initially respond well, resistance and relapse while on this drug is an emerging and critical issue in the clinic. Though some studies have begun uncovering the factors involved in resistance to BCL-2-targeting BH3-mimetic drugs, little focus has been applied to pre-emptively tackle resistance for the next generation of BH3-mimetic drugs targeting MCL-1, which are now in clinical trials for diverse blood cancers. Therefore, using pre-clinical mouse and human models of aggressive lymphoma, we sought to predict factors likely to contribute to the development of resistance in patients receiving MCL-1-targeting BH3-mimetic drugs. First, we performed multiple whole genome CRISPR/Cas9 KO screens and identified that loss of the pro-apoptotic effector protein BAX, but not its close relative BAK, could confer resistance to MCL-1-targeting BH3-mimetic drugs in both short-term and long-term treatment regimens, even in lymphoma cells lacking the tumour suppressor TRP53. Furthermore, we found that mouse Eµ-Myc lymphoma cells selected for loss of BAX, as well as upregulation of the untargeted pro-survival BCL-2 family proteins BCL-XL and A1, when made naturally resistant to MCL-1 inhibitors by culturing them in increasing doses of drug over time, a situation mimicking the clinical application of these drugs. Finally, we identified therapeutic approaches which could overcome these two methods of resistance: the use of chemotherapeutic drugs or combined BH3-mimetic treatment, respectively. Collectively, these results uncover some key factors likely to cause resistance to MCL-1 inhibition in the clinic and suggest rational therapeutic strategies to overcome resistance that should be investigated further.
Assuntos
Antineoplásicos , Proteínas Proto-Oncogênicas c-bcl-2 , Humanos , Animais , Camundongos , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Apoptose , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proteína bcl-X/metabolismoRESUMO
Mutant TP53 proteins are thought to drive the development and sustained expansion of cancers at least in part through the loss of the wild-type (wt) TP53 tumour suppressive functions. Therefore, compounds that can restore wt TP53 functions in mutant TP53 proteins are expected to inhibit the expansion of tumours expressing mutant TP53. APR-246 has been reported to exert such effects in malignant cells and is currently undergoing clinical trials in several cancer types. However, there is evidence that APR-246 may also kill malignant cells that do not express mutant TP53. To support the clinical development of APR-246 it is important to understand its mechanism(s) of action. By establishing isogenic background tumour cell lines with different TP53/TRP53 states, we found that APR-246 can kill malignant cells irrespective of their TP53/TRP53 status. Accordingly, RNAseq analysis revealed that treatment with APR-246 induces expression of the same gene set in Eµ-Myc mouse lymphoma cells of all four possible TRP53 states, wt, wt alongside mutant, knockout and knockout alongside mutant. We found that depending on the type of cancer cell and the concentration of APR-246 used, this compound can kill malignant cells through induction of various programmed cell death pathways, including apoptosis, necroptosis and ferroptosis. The sensitivity of non-transformed cells to APR-246 also depended on the cell type. These findings reveal that the clinical testing of APR-246 should not be limited to cancers expressing mutant TP53 but expanded to cancers that express wt TP53 or are TP53-deficient.
Assuntos
Genes p53 , Proteína Supressora de Tumor p53 , Animais , Camundongos , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Apoptose , Linhagem Celular Tumoral , MutaçãoRESUMO
Acquired resistance to cell death is a hallmark of cancer. The BCL-2 protein family members play important roles in controlling apoptotic cell death. Abnormal over-expression of pro-survival BCL-2 family members or abnormal reduction of pro-apoptotic BCL-2 family proteins, both resulting in the inhibition of apoptosis, are frequently detected in diverse malignancies. The critical role of the pro-survival and pro-apoptotic BCL-2 family proteins in the regulation of apoptosis makes them attractive targets for the development of agents for the treatment of cancer. This review describes the roles of the various pro-survival and pro-apoptotic members of the BCL-2 protein family in normal development and organismal function and how defects in the control of apoptosis promote the development and therapy resistance of cancer. Finally, we discuss the development of inhibitors of pro-survival BCL-2 proteins, termed BH3-mimetic drugs, as novel agents for cancer therapy.
Assuntos
Apoptose , Neoplasias , Humanos , Apoptose/fisiologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/metabolismoRESUMO
CRISPR technologies have advanced cancer modelling in mice, but CRISPR activation (CRISPRa) methods have not been exploited in this context. We establish a CRISPRa mouse (dCas9a-SAMKI) for inducing gene expression in vivo and in vitro. Using dCas9a-SAMKI primary lymphocytes, we induce B cell restricted genes in T cells and vice versa, demonstrating the power of this system. There are limited models of aggressive double hit lymphoma. Therefore, we transactivate pro-survival BCL-2 in Eµ-MycT/+;dCas9a-SAMKI/+ haematopoietic stem and progenitor cells. Mice transplanted with these cells rapidly develop lymphomas expressing high BCL-2 and MYC. Unlike standard Eµ-Myc lymphomas, BCL-2 expressing lymphomas are highly sensitive to the BCL-2 inhibitor venetoclax. We perform genome-wide activation screens in these lymphoma cells and find a dominant role for the BCL-2 protein A1 in venetoclax resistance. Here we show the potential of our CRISPRa model for mimicking disease and providing insights into resistance mechanisms towards targeted therapies.
Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Linfoma , Animais , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Linfoma/tratamento farmacológico , Linfoma/genética , Linfoma/patologia , Camundongos , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , SulfonamidasRESUMO
BFL-1 is an understudied pro-survival BCL-2 protein. The expression of BFL-1 is reported in many cancers, but it is yet to be clarified whether high transcript expression also always correlates with a pro-survival function. However, recent applications of BH3-mimetics for the treatment of blood cancers identified BFL-1 as a potential resistance factor in this type of cancer. Hence, understanding the role of BFL-1 in human cancers and how its up-regulation leads to therapy resistance has become an area of great clinical relevance. In addition, deletion of the murine homologue of BFL-1, called A1, in mice showed only minimal impacts on the well-being of these animals, suggesting drugs targeting BFL-1 would exhibit limited on-target toxicities. BFL-1 therefore represents a good clinical cancer target. Currently, no effective BFL-1 inhibitors exist, which is likely due to the underappreciation of BFL-1 as a potential target in the clinic and lack of understanding of the BFL-1 protein. In this review, the roles of BFL-1 in the development of different types of cancers and drug resistant mechanisms are discussed and some recent advances in the generation of BFL-1 inhibitors highlighted.
Assuntos
Neoplasias , Proteínas Proto-Oncogênicas c-bcl-2 , Animais , Apoptose , Humanos , Metilcelulose , Camundongos , Antígenos de Histocompatibilidade Menor/metabolismo , Neoplasias/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/farmacologiaRESUMO
Apoptosis is a form of programmed cell death that is regulated by the balance between prosurvival and proapoptotic BCL-2 protein family members. Evasion of apoptosis is a hallmark of cancer that arises when this balance is tipped in favour of survival. One form of anticancer therapeutic, termed 'BH3-mimetic drugs', has been developed to directly activate the apoptosis machinery in malignant cells. These drugs bind to and inhibit specific prosurvival BCL-2 family proteins, thereby mimicking their interaction with the BH3 domains of proapoptotic BCL-2 family proteins. The BCL-2-specific inhibitor venetoclax is approved by the US Food and Drug Administration and many regulatory authorities worldwide for the treatment of chronic lymphocytic leukaemia and acute myeloid leukaemia. BH3-mimetic drugs targeting other BCL-2 prosurvival proteins have been tested in preclinical models of cancer, and drugs targeting MCL-1 or BCL-XL have advanced into phase I clinical trials for certain cancers. As with all therapeutics, efficacy and tolerability need to be carefully balanced to achieve a therapeutic window whereby there is significant anticancer activity with an acceptable safety profile. In this Review, we outline the current state of BH3-mimetic drugs targeting various prosurvival BCL-2 family proteins and discuss emerging data regarding primary and acquired resistance to these agents and approaches that may overcome this. We highlight issues that need to be addressed to further advance the clinical application of BH3-mimetic drugs, both alone and in combination with additional anticancer agents (for example, standard chemotherapeutic drugs or inhibitors of oncogenic kinases), for improved responses in patients with cancer.
Assuntos
Antineoplásicos , Leucemia Linfocítica Crônica de Células B , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose , Linhagem Celular Tumoral , Humanos , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Oncogenes , Preparações Farmacêuticas , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/farmacologiaRESUMO
Selective targeting of BCL-2 with the BH3-mimetic venetoclax has been a transformative treatment for patients with various leukemias. TP-53 controls apoptosis upstream of where BCL-2 and its prosurvival relatives, such as MCL-1, act. Therefore, targeting these prosurvival proteins could trigger apoptosis across diverse blood cancers, irrespective of TP53 mutation status. Indeed, targeting BCL-2 has produced clinically relevant responses in blood cancers with aberrant TP-53. However, in our study, TP53-mutated or -deficient myeloid and lymphoid leukemias outcompeted isogenic controls with intact TP-53, unless sufficient concentrations of BH3-mimetics targeting BCL-2 or MCL-1 were applied. Strikingly, tumor cells with TP-53 dysfunction escaped and thrived over time if inhibition of BCL-2 or MCL-1 was sublethal, in part because of an increased threshold for BAX/BAK activation in these cells. Our study revealed the key role of TP-53 in shaping long-term responses to BH3-mimetic drugs and reconciled the disparate pattern of initial clinical response to venetoclax, followed by subsequent treatment failure among patients with TP53-mutant chronic lymphocytic leukemia or acute myeloid leukemia. In contrast to BH3-mimetics targeting just BCL-2 or MCL-1 at doses that are individually sublethal, a combined BH3-mimetic approach targeting both prosurvival proteins enhanced lethality and durably suppressed the leukemia burden, regardless of TP53 mutation status. Our findings highlight the importance of using sufficiently lethal treatment strategies to maximize outcomes of patients with TP53-mutant disease. In addition, our findings caution against use of sublethal BH3-mimetic drug regimens that may enhance the risk of disease progression driven by emergent TP53-mutant clones.
Assuntos
Antineoplásicos/farmacologia , Proteínas Reguladoras de Apoptose/antagonistas & inibidores , Apoptose/efeitos dos fármacos , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Indolizinas/farmacologia , Isoquinolinas/farmacologia , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Mieloide Aguda/tratamento farmacológico , Morfolinas/farmacologia , Proteínas de Neoplasias/fisiologia , Fragmentos de Peptídeos/antagonistas & inibidores , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Sulfonamidas/farmacologia , Proteína Supressora de Tumor p53/fisiologia , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/uso terapêutico , Apoptose/fisiologia , Proteínas Reguladoras de Apoptose/fisiologia , Compostos Bicíclicos Heterocíclicos com Pontes/administração & dosagem , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Sistemas CRISPR-Cas , Linhagem Celular Tumoral , Dano ao DNA , Genes p53 , Humanos , Indolizinas/uso terapêutico , Subunidade alfa de Receptor de Interleucina-2/deficiência , Isoquinolinas/uso terapêutico , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/terapia , Camundongos , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Morfolinas/uso terapêutico , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Proteínas de Neoplasias/antagonistas & inibidores , Fosforilação Oxidativa/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Sulfonamidas/administração & dosagem , Sulfonamidas/uso terapêutico , Proteína Supressora de Tumor p53/deficiência , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
MYC-driven B-cell lymphomas are addicted to increased levels of ribosome biogenesis (RiBi), offering the potential for therapeutic intervention. However, it is unclear whether inhibition of RiBi suppresses lymphomagenesis by decreasing translational capacity and/or by p53 activation mediated by the impaired RiBi checkpoint (IRBC). Here we generated Eµ-Myc lymphoma cells expressing inducible short hairpin RNAs to either ribosomal protein L7a (RPL7a) or RPL11, the latter an essential component of the IRBC. The loss of either protein reduced RiBi, protein synthesis, and cell proliferation to similar extents. However, only RPL7a depletion induced p53-mediated apoptosis through the selective proteasomal degradation of antiapoptotic MCL-1, indicating the critical role of the IRBC in this mechanism. Strikingly, low concentrations of the US Food and Drug Administration-approved anticancer RNA polymerase I inhibitor Actinomycin D (ActD) dramatically prolonged the survival of mice harboring Trp53+/+;Eµ-Myc but not Trp53-/-;Eµ-Myc lymphomas, which provides a rationale for treating MYC-driven B-cell lymphomas with ActD. Importantly, the molecular effects of ActD on Eµ-Myc cells were recapitulated in human B-cell lymphoma cell lines, highlighting the potential for ActD as a therapeutic avenue for p53 wild-type lymphoma.
Assuntos
Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Dactinomicina/farmacologia , Linfoma de Células B , Proteína de Sequência 1 de Leucemia de Células Mieloides , Proteólise/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-myc , Ribossomos , Proteína Supressora de Tumor p53 , Animais , Pontos de Checagem do Ciclo Celular/genética , Linhagem Celular Tumoral , Linfoma de Células B/tratamento farmacológico , Linfoma de Células B/genética , Linfoma de Células B/metabolismo , Masculino , Camundongos , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Proteínas Ribossômicas/antagonistas & inibidores , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
FOXP3+ regulatory T (Treg) cells are essential for maintaining immunological tolerance. Given their importance in immune-related diseases, cancer and obesity, there is increasing interest in targeting the Treg cell compartment therapeutically. New pharmacological inhibitors that specifically target the prosurvival protein MCL-1 may provide this opportunity, as Treg cells are particularly reliant upon this protein. However, there are two distinct isoforms of MCL-1; one located at the outer mitochondrial membrane (OMM) that is required to antagonize apoptosis, and another at the inner mitochondrial membrane (IMM) that is reported to maintain IMM structure and metabolism via ATP production during oxidative phosphorylation. We set out to elucidate the relative importance of these distinct biological functions of MCL-1 in Treg cells to assess whether MCL-1 inhibition might impact upon the metabolism of cells able to resist apoptosis. Conditional deletion of Mcl1 in FOXP3+ Treg cells resulted in a lethal multiorgan autoimmunity due to the depletion of the Treg cell compartment. This striking phenotype was completely rescued by concomitant deletion of the apoptotic effector proteins BAK and BAX, indicating that apoptosis plays a pivotal role in the homeostasis of Treg cells. Notably, MCL-1-deficient Treg cells rescued from apoptosis displayed normal metabolic capacity. Moreover, pharmacological inhibition of MCL-1 in Treg cells resistant to apoptosis did not perturb their metabolic function. We conclude that Treg cells require MCL-1 only to antagonize apoptosis and not for metabolism. Therefore, MCL-1 inhibition could be used to manipulate Treg cell survival for clinical benefit without affecting the metabolic fitness of cells resisting apoptosis.
Assuntos
Apoptose/imunologia , Fatores de Transcrição Forkhead/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Animais , Apoptose/genética , Sobrevivência Celular/genética , Sobrevivência Celular/imunologia , Feminino , Fatores de Transcrição Forkhead/genética , Deleção de Genes , Homeostase/imunologia , Tolerância Imunológica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Transdução de SinaisRESUMO
Dysregulated expression of BCL-2 family proteins allows cancer cells to escape apoptosis. To counter this, BH3-mimetic drugs that target and inhibit select BCL-2 prosurvival proteins to induce apoptosis have been developed for cancer therapy. Venetoclax, which targets BCL-2, has been effective as therapy for patients with chronic lymphocytic leukemia, and MCL-1-targeting BH3-mimetic drugs have been extensively evaluated in preclinical studies for a range of blood cancers. Recently, BCL-W, a relatively understudied prosurvival member of the BCL-2 protein family, has been reported to be abnormally upregulated in Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL), and Hodgkin lymphoma patient samples. Therefore, to determine if BCL-W would be a promising therapeutic target for B-cell lymphomas, we have examined the role of BCL-W in the sustained growth of human BL- and DLBCL-derived cell lines. We found that CRISPR/CAS9-mediated loss or short hairpin RNA-mediated knockdown of BCL-W expression in selected BL and DLBCL cell lines did not lead to spontaneous apoptosis and had no effect on their sensitivity to a range of BH3-mimetic drugs targeting other BCL-2 prosurvival proteins. Our results suggest that BCL-W is not universally required for the sustained growth and survival of human BL and DLBCL cell lines. Thus, targeting BCL-W in this subset of B-cell lymphomas may not be of broad therapeutic benefit.
Assuntos
Proteínas Reguladoras de Apoptose/farmacologia , Linfoma de Burkitt/tratamento farmacológico , Proteínas Reguladoras de Apoptose/metabolismo , Linfoma de Burkitt/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/patologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/farmacologiaRESUMO
One fundamental property of a stem cell niche is the exchange of molecular signals between its component cells. Niche models, such as the Drosophila melanogaster testis, have been instrumental in identifying and studying the conserved genetic factors that contribute to niche molecular signalling. Here, we identify jam packed (jam), an allele of Striatin interacting protein (Strip), which is a core member of the highly conserved Striatin-interacting phosphatase and kinase (STRIPAK) complex. In the developing Drosophila testis, Strip cell-autonomously regulates the differentiation and morphology of the somatic lineage, and non-cell-autonomously regulates the proliferation and differentiation of the germline lineage. Mechanistically, Strip acts in the somatic lineage with its STRIPAK partner, Connector of kinase to AP-1 (Cka), where they negatively regulate the Jun N-terminal kinase (JNK) signalling pathway. Our study reveals a novel role for Strip/Cka in JNK pathway regulation during spermatogenesis within the developing Drosophila testis.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Proteínas de Drosophila/fisiologia , Drosophila melanogaster , Sistema de Sinalização das MAP Quinases/genética , Proteínas de Ligação a Fosfato/fisiologia , Espermatogênese/genética , Animais , Animais Geneticamente Modificados , Diferenciação Celular , Regulação para Baixo/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Masculino , Testículo/citologia , Testículo/crescimento & desenvolvimento , Testículo/metabolismoRESUMO
Genetic lesions of the ß-globin gene result in haemoglobinopathies such as ß-thalassemia and sickle cell disease. To discover and test new molecular medicines for ß-haemoglobinopathies, cell-based and animal models are now being widely utilised. However, multiple in vitro and in vivo models are required due to the complex structure and regulatory mechanisms of the human globin gene locus, subtle species-specific differences in blood cell development, and the influence of epigenetic factors. Advances in genome sequencing, gene editing, and precision medicine have enabled the first generation of molecular therapies aimed at reactivating, repairing, or replacing silenced or damaged globin genes. Here we compare and contrast current animal and cell-based models, highlighting their complementary strengths, reflecting on how they have informed the scope and direction of the field, and describing some of the novel molecular and precision medicines currently under development or in clinical trial.