RESUMO
BACKGROUND: Prostate cancer is the most common cancer in men in the developed world, with most deaths caused by advanced and metastatic disease which has no curative options. Here, we identified Mbtps2 alteration to be associated with metastatic disease in an unbiased in vivo screen and demonstrated its regulation of fatty acid and cholesterol metabolism. METHODS: The Sleeping Beauty transposon system was used to randomly alter gene expression in the PtenNull murine prostate. MBTPS2 was knocked down by siRNA in LNCaP, DU145 and PC3 cell lines, which were then phenotypically investigated. RNA-Seq was performed on LNCaP cells lacking MBTPS2, and pathways validated by qPCR. Cholesterol metabolism was investigated by Filipin III staining. RESULTS: Mbtps2 was identified in our transposon-mediated in vivo screen to be associated with metastatic prostate cancer. Silencing of MBTPS2 expression in LNCaP, DU145 and PC3 human prostate cancer cells reduced proliferation and colony forming growth in vitro. Knockdown of MBTPS2 expression in LNCaP cells impaired cholesterol synthesis and uptake along with reduced expression of key regulators of fatty acid synthesis, namely FASN and ACACA. CONCLUSION: MBTPS2 is implicated in progressive prostate cancer and may mechanistically involve its effects on fatty acid and cholesterol metabolism.
Assuntos
Lipogênese , Neoplasias da Próstata , Masculino , Humanos , Animais , Camundongos , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Linhagem Celular Tumoral , Neoplasias da Próstata/patologia , Colesterol , Ácidos Graxos , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Metaloendopeptidases/genética , Metaloendopeptidases/metabolismoRESUMO
Avoidance of apoptosis is critical for the development and sustained growth of tumours. The pro-survival protein myeloid cell leukemia 1 (MCL1) is overexpressed in many cancers, but the development of small molecules targeting this protein that are amenable for clinical testing has been challenging. Here we describe S63845, a small molecule that specifically binds with high affinity to the BH3-binding groove of MCL1. Our mechanistic studies demonstrate that S63845 potently kills MCL1-dependent cancer cells, including multiple myeloma, leukaemia and lymphoma cells, by activating the BAX/BAK-dependent mitochondrial apoptotic pathway. In vivo, S63845 shows potent anti-tumour activity with an acceptable safety margin as a single agent in several cancers. Moreover, MCL1 inhibition, either alone or in combination with other anti-cancer drugs, proved effective against several solid cancer-derived cell lines. These results point towards MCL1 as a target for the treatment of a wide range of tumours.
Assuntos
Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Modelos Biológicos , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Tiofenos/farmacologia , Tiofenos/uso terapêutico , Animais , Antineoplásicos/administração & dosagem , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Feminino , Humanos , Leucemia/tratamento farmacológico , Leucemia/metabolismo , Leucemia/patologia , Linfoma/tratamento farmacológico , Linfoma/metabolismo , Linfoma/patologia , Masculino , Camundongos , Modelos Moleculares , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Proteína de Sequência 1 de Leucemia de Células Mieloides/química , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Neoplasias/metabolismo , Pirimidinas/administração & dosagem , Tiofenos/administração & dosagem , Ensaios Antitumorais Modelo de Xenoenxerto , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismoRESUMO
Prostate cancer (CaP) is the most common adult male cancer in the developed world. The paucity of biomarkers to predict prostate tumor biology makes it important to identify key pathways that confer poor prognosis and guide potential targeted therapy. Using a murine forward mutagenesis screen in a Pten-null background, we identified peroxisome proliferator-activated receptor gamma (Pparg), encoding a ligand-activated transcription factor, as a promoter of metastatic CaP through activation of lipid signaling pathways, including up-regulation of lipid synthesis enzymes [fatty acid synthase (FASN), acetyl-CoA carboxylase (ACC), ATP citrate lyase (ACLY)]. Importantly, inhibition of PPARG suppressed tumor growth in vivo, with down-regulation of the lipid synthesis program. We show that elevated levels of PPARG strongly correlate with elevation of FASN in human CaP and that high levels of PPARG/FASN and PI3K/pAKT pathway activation confer a poor prognosis. These data suggest that CaP patients could be stratified in terms of PPARG/FASN and PTEN levels to identify patients with aggressive CaP who may respond favorably to PPARG/FASN inhibition.
Assuntos
Ácido Graxo Sintase Tipo I/metabolismo , PPAR gama/metabolismo , PTEN Fosfo-Hidrolase/metabolismo , Neoplasias da Próstata/metabolismo , Idoso , Idoso de 80 Anos ou mais , Animais , Linhagem Celular Tumoral , Humanos , Metabolismo dos Lipídeos , Masculino , Camundongos , Pessoa de Meia-Idade , PPAR gama/genética , PTEN Fosfo-Hidrolase/genética , Fosfatidilinositol 3-Quinases/metabolismo , Neoplasias da Próstata/patologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , TransposasesRESUMO
The X-linked disease Barth syndrome (BTHS) is caused by mutations in TAZ; TAZ is the main determinant of the final acyl chain composition of the mitochondrial-specific phospholipid, cardiolipin. To date, a detailed characterization of endogenous TAZ has only been performed in yeast. Further, why a given BTHS-associated missense mutation impairs TAZ function has only been determined in a yeast model of this human disease. Presently, the detailed characterization of yeast tafazzin harboring individual BTHS mutations at evolutionarily conserved residues has identified seven distinct loss-of-function mechanisms caused by patient-associated missense alleles. However, whether the biochemical consequences associated with individual mutations also occur in the context of human TAZ in a validated mammalian model has not been demonstrated. Here, utilizing newly established monoclonal antibodies capable of detecting endogenous TAZ, we demonstrate that mammalian TAZ, like its yeast counterpart, is localized to the mitochondrion where it adopts an extremely protease-resistant fold, associates non-integrally with intermembrane space-facing membranes and assembles in a range of complexes. Even though multiple isoforms are expressed at the mRNA level, only a single polypeptide that co-migrates with the human isoform lacking exon 5 is expressed in human skin fibroblasts, HEK293 cells, and murine heart and liver mitochondria. Finally, using a new genome-edited mammalian BTHS cell culture model, we demonstrate that the loss-of-function mechanisms for two BTHS alleles that represent two of the seven functional classes of BTHS mutation as originally defined in yeast, are the same when modeled in human TAZ.
Assuntos
Síndrome de Barth/genética , Fibroblastos/metabolismo , Mitocôndrias Cardíacas/metabolismo , Mitocôndrias Hepáticas/metabolismo , Mutação/genética , Pele/metabolismo , Fatores de Transcrição/metabolismo , Aciltransferases , Animais , Síndrome de Barth/metabolismo , Síndrome de Barth/patologia , Células Cultivadas , Fibroblastos/citologia , Células HEK293 , Humanos , Camundongos , Mitocôndrias Cardíacas/patologia , Mitocôndrias Hepáticas/patologia , Isoformas de Proteínas , Pele/citologia , Fatores de Transcrição/classificação , Fatores de Transcrição/genéticaRESUMO
The link between prostate cancer (PC) development and lipid metabolism is well established, with AR intimately involved in a number of lipogenic processes involving SREBP1, PPARG, FASN, ACC, ACLY and SCD1. Recently, there is growing evidence implicating the role of obesity and peri-prostatic adipose tissue (PPAT) in PC aggressiveness and related mortality, suggesting the importance of lipid pathways in both localised and disseminated disease. A number of promising agents are in development to target the lipogenic axis in PC, and the likelihood is that these agents will form part of combination drug strategies, with targeting of multiple metabolic pathways (e.g. FASN and CPT1), or in combination with AR pathway inhibitors (SCD1 and AR).
Assuntos
Metabolismo dos Lipídeos , Próstata/metabolismo , Neoplasias da Próstata/metabolismo , Animais , Descoberta de Drogas , Ácido Graxo Sintases/metabolismo , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , PPAR gama/metabolismo , Próstata/efeitos dos fármacos , Próstata/patologia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , Transdução de Sinais/efeitos dos fármacos , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismoRESUMO
Vaginal self collection (SC) is safe and effective for human papillomavirus (HPV) testing and can increase cervical cancer screening coverage for underserved women. To better understand the impact of SC methodology on HPV test outcomes, empirical testing was conducted using different swab collection workflows. Deposition of the collection swab into resuspension buffer resulted in a 2.4-cycle reduction in threshold detection of human beta-hemoglobin during PCR when compared to "swirl-and-toss". In addition, reducing the swab resuspension volume from 10 mL to 3 mL resulted in a 2.6-cycle reduction in threshold detection of human beta-globin. A systematic literature search (01/01/2020 to 08/02/2023) of Ovid Medline and Embase, followed by data extraction and analysis, was conducted to further assess the impact of resuspension volume on performance following SC. HPV test performance for SC, relative to clinician collection (CC), was calculated for detection of cervical pre-cancer. Data were stratified by the resuspension volume ratio of SC to CC being either ≥ 1.0 or < 1.0. SC with a volume ratio of ≥ 1.0 and < 1.0 had a relative ≥ CIN2 sensitivity of 92.0 % (95 % CI: 88.0, 96.0) and 97.0 % (95 % CI: 94.0, 100), respectively. Taken together, these results suggest that SC conditions can be modified to optimize sample recovery and performance, as part of cervical cancer screening.
RESUMO
ARF GTPases are central regulators of membrane trafficking that control local membrane identity and remodeling facilitating vesicle formation. Unraveling their function is complicated by the overlapping association of ARFs with guanine nucleotide exchange factors (GEFs), GTPase-activating proteins (GAPs), and numerous interactors. Through a functional genomic screen of three-dimensional (3D) prostate cancer cell behavior, we explore the contribution of ARF GTPases, GEFs, GAPs, and interactors to collective invasion. This revealed that ARF3 GTPase regulates the modality of invasion, acting as a switch between leader cell-led chains of invasion or collective sheet movement. Functionally, the ability of ARF3 to control invasion modality is dependent on association and subsequent control of turnover of N-cadherin. In vivo, ARF3 levels acted as a rheostat for metastasis from intraprostatic tumor transplants and ARF3/N-cadherin expression can be used to identify prostate cancer patients with metastatic, poor-outcome disease. Our analysis defines a unique function for the ARF3 GTPase in controlling how cells collectively organize during invasion and metastasis.
Assuntos
Fatores de Ribosilação do ADP , Proteínas Ativadoras de GTPase , Proteínas Monoméricas de Ligação ao GTP , Neoplasias da Próstata , Humanos , Masculino , Fatores de Ribosilação do ADP/genética , Caderinas/genética , Endocitose , Proteínas Ativadoras de GTPase/genética , Neoplasias da Próstata/genéticaRESUMO
The glycocalyx component and sialomucin podocalyxin (PODXL) is required for normal tissue development by promoting apical membranes to form between cells, triggering lumen formation. Elevated PODXL expression is also associated with metastasis and poor clinical outcome in multiple tumor types. How PODXL presents this duality in effect remains unknown. We identify an unexpected function of PODXL as a decoy receptor for galectin-3 (GAL3), whereby the PODXL-GAL3 interaction releases GAL3 repression of integrin-based invasion. Differential cortical targeting of PODXL, regulated by ubiquitination, is the molecular mechanism controlling alternate fates. Both PODXL high and low surface levels occur in parallel subpopulations within cancer cells. Orthotopic intraprostatic xenograft of PODXL-manipulated cells or those with different surface levels of PODXL define that this axis controls metastasis in vivo. Clinically, interplay between PODXL-GAL3 stratifies prostate cancer patients with poor outcome. Our studies define the molecular mechanisms and context in which PODXL promotes invasion and metastasis.
Assuntos
Glicocálix , Sialoglicoproteínas , Masculino , Humanos , Glicocálix/metabolismo , Sialoglicoproteínas/metabolismo , Xenoenxertos , Transplante HeterólogoRESUMO
BACKGROUND: Lipids are best known for their fundamental role in forming biological membranes and as intracellular signalling molecules. Interactions between proteins and lipids are central to nearly every cellular process yet these crucial relationships often go overlooked. Changes or switches in the lipid profile of a cell drastically affects cellular metabolism and signal transduction. In relationship to cancer, upregulation of lipid metabolism is often observed during the early stages of neoplasia and is a recognised hallmark of many types of cancer. METHODS: We performed a comprehensive review of the literature using PubMed regarding lipid metabolism in cancer and the importance of protein-lipid interactions in the function of mitochondria. RESULTS: An increase in the basal rate of de novo lipogenesis generates a substantial rise in the saturated fatty acid content of cellular membranes. The ensuing alteration in the acyl chain profile of phospholipids has severe consequences on the function of organelles and membrane-bound proteins, and result in a host of pathologies including the cardiac disorder Barth Syndrome. CONCLUSIONS: Although increased lipogenesis is specifically selected for during cellular transformation it remains unclear if it confers an advantage for survival or is a byproduct of more global changes in cellular metabolism. We discuss the current data regarding the potential of targeting the lipogenic switch as a cancer therapy. In addition, we describe the importance of mitochondrial phospholipid composition during a number mitochondria-driven events observed to have roles in cancer. We specifically highlight the function of cardiolipin in maintaining mitochondrial structure, regulating mitochondrial dynamics and bioenergetics as well as its contributions to mitophagy/autophagy and apoptosis.
Assuntos
Membrana Celular/metabolismo , Fenômenos Fisiológicos Celulares , Metabolismo dos Lipídeos/fisiologia , Fosfolipídeos/metabolismo , HumanosRESUMO
Peroxisome Proliferator-Activated Receptor Gamma (PPARG) is one of the three members of the PPAR family of transcription factors. Besides its roles in adipocyte differentiation and lipid metabolism, we recently demonstrated an association between PPARG and metastasis in prostate cancer. In this study a functional effect of PPARG on AKT serine/threonine kinase 3 (AKT3), which ultimately results in a more aggressive disease phenotype was identified. AKT3 has previously been shown to regulate PPARG co-activator 1 alpha (PGC1α) localisation and function through its action on chromosome maintenance region 1 (CRM1). AKT3 promotes PGC1α localisation to the nucleus through its inhibitory effects on CRM1, a known nuclear export protein. Collectively our results demonstrate how PPARG over-expression drives an increase in AKT3 levels, which in turn has the downstream effect of increasing PGC1α localisation within the nucleus, driving mitochondrial biogenesis. Furthermore, this increase in mitochondrial mass provides higher energetic output in the form of elevated ATP levels which may fuel the progression of the tumour cell through epithelial to mesenchymal transition (EMT) and ultimately metastasis.
Assuntos
PPAR gama/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Neoplasias da Próstata/genética , Proteínas Proto-Oncogênicas c-akt/genética , Animais , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Carioferinas/genética , Metabolismo dos Lipídeos/genética , Masculino , Camundongos , Mitocôndrias/genética , Biogênese de Organelas , Neoplasias da Próstata/patologia , Receptores Citoplasmáticos e Nucleares/genética , Proteína Exportina 1RESUMO
The signalling pathways underpinning cell growth and invasion use overlapping components, yet how mutually exclusive cellular responses occur is unclear. Here, we report development of 3-Dimensional culture analyses to separately quantify growth and invasion. We identify that alternate variants of IQSEC1, an ARF GTPase Exchange Factor, act as switches to promote invasion over growth by controlling phosphoinositide metabolism. All IQSEC1 variants activate ARF5- and ARF6-dependent PIP5-kinase to promote PI(3,4,5)P3-AKT signalling and growth. In contrast, select pro-invasive IQSEC1 variants promote PI(3,4,5)P3 production to form invasion-driving protrusions. Inhibition of IQSEC1 attenuates invasion in vitro and metastasis in vivo. Induction of pro-invasive IQSEC1 variants and elevated IQSEC1 expression occurs in a number of tumour types and is associated with higher-grade metastatic cancer, activation of PI(3,4,5)P3 signalling, and predicts long-term poor outcome across multiple cancers. IQSEC1-regulated phosphoinositide metabolism therefore is a switch to induce invasion over growth in response to the same external signal. Targeting IQSEC1 as the central regulator of this switch may represent a therapeutic vulnerability to stop metastasis.
Assuntos
Fatores de Troca do Nucleotídeo Guanina/metabolismo , Metástase Neoplásica , Fosfatidilinositóis/metabolismo , Transdução de Sinais , Fator 6 de Ribosilação do ADP , Fatores de Ribosilação do ADP/metabolismo , Animais , Carcinogênese/genética , Carcinogênese/metabolismo , Linhagem Celular Tumoral , Fatores de Troca do Nucleotídeo Guanina/genética , Xenoenxertos , Humanos , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Masculino , Camundongos , Camundongos Nus , Metástase Neoplásica/genética , Neoplasias/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismoRESUMO
Androgen deprivation therapy (ADT) is the standard of care for treatment of nonresectable prostate cancer. Despite high treatment efficiency, most patients ultimately develop lethal castration-resistant prostate cancer (CRPC). In this study, we performed a comparative proteomic analysis of three in vivo, androgen receptor (AR)-responsive orthograft models of matched hormone-naïve prostate cancer and CRPC. Differential proteomic analysis revealed that distinct molecular mechanisms, including amino acid (AA) and fatty acid metabolism, are involved in the response to ADT in the different models. Despite this heterogeneity, Schlafen family member 5 (SLFN5) was identified as an AR-regulated protein in CRPC. SLFN5 expression was high in CRPC tumors and correlated with poor patient outcome. In vivo, SLFN5 depletion strongly impaired tumor growth in castrated conditions. Mechanistically, SLFN5 interacted with ATF4 and regulated the expression of LAT1, an essential AA transporter. Consequently, SLFN5 depletion in CRPC cells decreased intracellular levels of essential AA and impaired mTORC1 signaling in a LAT1-dependent manner. These results confirm that these orthograft models recapitulate the high degree of heterogeneity observed in patients with CRPC and further highlight SLFN5 as a clinically relevant target for CRPC. SIGNIFICANCE: This study identifies SLFN5 as a novel regulator of the LAT1 amino acid transporter and an essential contributor to mTORC1 activity in castration-resistant prostate cancer.
Assuntos
Biomarcadores Tumorais/metabolismo , Proteínas de Ciclo Celular/metabolismo , Regulação Neoplásica da Expressão Gênica , Transportador 1 de Aminoácidos Neutros Grandes/metabolismo , Neoplasias de Próstata Resistentes à Castração/patologia , Serina-Treonina Quinases TOR/metabolismo , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Animais , Apoptose , Biomarcadores Tumorais/genética , Proteínas de Ciclo Celular/genética , Proliferação de Células , Humanos , Transportador 1 de Aminoácidos Neutros Grandes/genética , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Metaboloma , Camundongos , Camundongos Nus , Prognóstico , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/metabolismo , Proteoma , Taxa de Sobrevida , Serina-Treonina Quinases TOR/genética , Transcriptoma , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The characterization of prostate epithelial hierarchy and lineage heterogeneity is critical to understand its regenerative properties and malignancies. Here, we report that the transcription factor RUNX1 marks a specific subpopulation of proximal luminal cells (PLCs), enriched in the periurethral region of the developing and adult mouse prostate, and distinct from the previously identified NKX3.1+ luminal castration-resistant cells. Using scRNA-seq profiling and genetic lineage tracing, we show that RUNX1+ PLCs are unaffected by androgen deprivation, and do not contribute to the regeneration of the distal luminal compartments. Furthermore, we demonstrate that a transcriptionally similar RUNX1+ population emerges at the onset of embryonic prostate specification to populate the proximal region of the ducts. Collectively, our results reveal that RUNX1+ PLCs is an intrinsic castration-resistant and self-sustained lineage that emerges early during prostate development and provide new insights into the lineage relationships of the prostate epithelium.
The prostate is part of the reproductive organs in male mammals. Many of the cells lining the inside of the prostate known as 'luminal cells' need hormones to survive. Certain treatments for prostate cancer, including surgical and chemical castration, lead to fewer hormones reaching the prostate, which shrinks as luminal cells die. But some of these luminal cells are able to survive the damaging effects of castration, rebuilding the prostate upon treatment with hormones, which can lead to the cancer reappearing. It is unclear which type of luminal cells survive during periods without hormones and are responsible for regenerating the prostate. RUNX1 is a protein responsible for switching genes on and off, and is usually found in blood cells, which it helps to mature and perform their roles, but has also been detected in tissues that depend on hormones. Since the luminal cells of the prostate rely on hormones, could RUNX1 also be present in these cells? To answer this question, Mével et al. used mice to determine where and when RUNX1 is found in prostate cells. Mével et al. detected high levels of RUNX1 in a patch of luminal cells at the base of the prostate. Samples of these cells were taken for further testing from developing mouse embryos, healthy adult mice and mice in which the prostate was regenerating after surgical castration. Mével et al. found that these cells were a distinct subtype of luminal cells that were able to resist the effects of castration they survived without hormones. Though these cells were present during the early stages of prostate embryonic development and in healthy adult prostate tissue, they were not responsible for rebuilding the prostate after castration. Mével et al.'s results indicate that, in mice, RUNX1 may act as a marker for a subset of luminal cells that can survive after castration. Further probing the roles of these castration-resistant luminal cells in normal and cancerous prostate tissue may improve the outcome of patients with prostate cancer treated with hormone deprivation therapy.
Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/fisiologia , Próstata/crescimento & desenvolvimento , Animais , Linhagem da Célula , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Epitélio/metabolismo , Masculino , Camundongos , Orquiectomia , Próstata/citologia , Próstata/metabolismoRESUMO
Epstein-Barr virus (EBV), which is ubiquitous in the adult population, is causally associated with human malignancies. Like many infectious agents, EBV has evolved strategies to block host cell death, including through expression of viral homologues of cellular BCL-2 pro-survival proteins (vBCL-2s), such as BHRF1. Small molecule inhibitors of the cellular pro-survival BCL-2 family proteins, termed 'BH3-mimetics', have entered clinical trials for blood cancers with the BCL-2 inhibitor venetoclax already approved for treatment of therapy refractory chronic lymphocytic leukaemia and acute myeloid leukaemia in the elderly. The generation of BH3-mimetics that could specifically target vBCL-2 proteins may be an attractive therapeutic option for virus-associated cancers, since these drugs would be expected to only kill virally infected cells with only minimal side effects on normal healthy tissues. To achieve this, a better understanding of the contribution of vBCL-2 proteins to tumorigenesis and insights into their biochemical functions is needed. In the context of Burkitt lymphoma (BL), BHRF1 expression conferred strong resistance to diverse apoptotic stimuli. Furthermore, BHRF1 expression in mouse haematopoietic stem and progenitor cells accelerated MYC-induced lymphoma development in a model of BL. BHRF1 interacts with the cellular pro-apoptotic BCL-2 proteins, BIM, BID, PUMA and BAK, but its capability to inhibit apoptosis could not be mapped solely to one of these interactions, suggesting plasticity is a key feature of BHRF1. Site-directed mutagenesis revealed a site in BHRF1 that was critical for its interaction with PUMA and blocking DNA-damage-induced apoptosis, identifying a potentially therapeutically targetable vulnerability in BHRF1.
Assuntos
Apoptose , Linfoma de Burkitt/patologia , Carcinogênese/patologia , Resistencia a Medicamentos Antineoplásicos , Proteínas Proto-Oncogênicas c-bcl-2/química , Homologia de Sequência de Aminoácidos , Proteínas Virais/metabolismo , Animais , Apoptose/genética , Proteína 11 Semelhante a Bcl-2/metabolismo , Linfoma de Burkitt/virologia , Morte Celular , Linhagem Celular Tumoral , Citoproteção , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Mutação com Perda de Função , Camundongos , Camundongos Endogâmicos C57BL , Ligação Proteica , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Virais/química , Proteínas Virais/genética , Latência ViralRESUMO
The incorporation of transition metal catalysts to the bioorthogonal toolbox has opened the possibility of producing supra-stoichiometric amounts of xenobiotics in living systems in a non-enzymatic fashion. For medical use, such metals could be embedded in implantable devices (i.e. heterogeneous catalyst) to "synthesize" drugs in desired locations (e.g. in a tumour) with high specificity and for extended periods of time, overcoming the useful life limitations of current local therapy modalities directed to specific organ sites (e.g. brachytherapy, controlled release systems). To translate this approach into a bona fide therapeutic option, it is essential to develop clinically-accessible implantation procedures and to understand and validate the activation process in relevant preclinical models. Herein we report the development of a novel Pd-activatable precursor of the red-fluorescent drug doxorubicin and Pd devices of optimized size and activity. Screening in state-of-the-art cancer models provided fundamental insights into the insertion protocols, safety and stability of the devices and into the prodrug distribution profile before and after activation.
RESUMO
BRAF inhibitors can extend progression-free and overall survival in melanoma patients whose tumors harbor mutations in BRAF. However, the majority of patients eventually develop resistance to these drugs. Here we show that BRAF mutant melanoma cells that have developed acquired resistance to BRAF inhibitors display increased oxidative metabolism and increased dependency on mitochondria for survival. Intriguingly, the increased oxidative metabolism is associated with a switch from glucose to glutamine metabolism and an increased dependence on glutamine over glucose for proliferation. We show that the resistant cells are more sensitive to mitochondrial poisons and to inhibitors of glutaminolysis, suggesting that targeting specific metabolic pathways may offer exciting therapeutic opportunities to treat resistant tumors, or to delay emergence of resistance in the first-line setting.
Assuntos
Glutamina/metabolismo , Melanoma/metabolismo , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Animais , Linhagem Celular Tumoral , Xenoenxertos , Humanos , Camundongos , Proteínas Proto-Oncogênicas B-raf/genéticaRESUMO
A mutation in the Drosophila gene technical knockout (tko(25t)), encoding mitoribosomal protein S12, phenocopies human mitochondrial disease. We isolated three spontaneous X-dominant suppressors of tko(25t) (designated Weeble), exhibiting almost wild-type phenotype and containing overlapping segmental duplications including the mutant allele, plus a second mitoribosomal protein gene, mRpL14. Ectopic, expressed copies of tko(25t) and mRpL14 conferred no phenotypic suppression. When placed over a null allele of tko, Weeble retained the mutant phenotype, even in the presence of additional transgenic copies of tko(25t). Increased mutant gene dosage can thus compensate the mutant phenotype, but only when located in its normal chromosomal context.