RESUMEN
In acute promyelocytic leukemia (APL), the promyelocytic leukemia-retinoic acid receptor alpha (PML/RARα) fusion protein destroys PML nuclear bodies (NBs), leading to the formation of microspeckles. However, our understanding, largely learned from morphological observations, lacks insight into the mechanisms behind PML/RARα-mediated microspeckle formation and its role in APL leukemogenesis. This study presents evidence uncovering liquid-liquid phase separation (LLPS) as a key mechanism in the formation of PML/RARα-mediated microspeckles. This process is facilitated by the intrinsically disordered region containing a large portion of PML and a smaller segment of RARα. We demonstrate the coassembly of bromodomain-containing protein 4 (BRD4) within PML/RARα-mediated condensates, differing from wild-type PML-formed NBs. In the absence of PML/RARα, PML NBs and BRD4 puncta exist as two independent phases, but the presence of PML/RARα disrupts PML NBs and redistributes PML and BRD4 into a distinct phase, forming PML/RARα-assembled microspeckles. Genome-wide profiling reveals a PML/RARα-induced BRD4 redistribution across the genome, with preferential binding to super-enhancers and broad-promoters (SEBPs). Mechanistically, BRD4 is recruited by PML/RARα into nuclear condensates, facilitating BRD4 chromatin binding to exert transcriptional activation essential for APL survival. Perturbing LLPS through chemical inhibition (1, 6-hexanediol) significantly reduces chromatin co-occupancy of PML/RARα and BRD4, attenuating their target gene activation. Finally, a series of experimental validations in primary APL patient samples confirm that PML/RARα forms microspeckles through condensates, recruits BRD4 to coassemble condensates, and co-occupies SEBP regions. Our findings elucidate the biophysical, pathological, and transcriptional dynamics of PML/RARα-assembled microspeckles, underscoring the importance of BRD4 in mediating transcriptional activation that enables PML/RARα to initiate APL.
Asunto(s)
Proteínas de Ciclo Celular , Leucemia Promielocítica Aguda , Proteínas de Fusión Oncogénica , Factores de Transcripción , Humanos , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/patología , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Fusión Oncogénica/metabolismo , Proteínas de Fusión Oncogénica/genética , Línea Celular Tumoral , Regulación Leucémica de la Expresión Génica , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Proteína de la Leucemia Promielocítica/metabolismo , Proteína de la Leucemia Promielocítica/genética , Separación de Fases , Proteínas que Contienen BromodominioRESUMEN
The alternative lengthening of telomeres (ALT) pathway maintains telomere length in a significant fraction of cancers that are associated with poor clinical outcomes. A better understanding of ALT mechanisms is therefore necessary for developing new treatment strategies for ALT cancers. SUMO modification of telomere proteins contributes to the formation of ALT telomere-associated PML bodies (APBs), in which telomeres are clustered and DNA repair proteins are enriched to promote homology-directed telomere DNA synthesis in ALT. However, it is still unknown whether-and if so, how-SUMO supports ALT beyond APB formation. Here, we show that SUMO condensates that contain DNA repair proteins enable telomere maintenance in the absence of APBs. In PML knockout ALT cell lines that lack APBs, we found that SUMOylation is required for manifesting ALT features independent of PML and APBs. Chemically induced telomere targeting of SUMO produces condensate formation and ALT features in PML-null cells. This effect requires both SUMOylation and interactions between SUMO and SUMO interaction motifs (SIMs). Mechanistically, SUMO-induced effects are associated with the accumulation of DNA repair proteins, including Rad52, Rad51AP1, RPA, and BLM, at telomeres. Furthermore, Rad52 can undergo phase separation, enrich SUMO at telomeres, and promote telomere DNA synthesis in collaboration with the BLM helicase in a SUMO-dependent manner. Collectively, our findings suggest that SUMO condensate formation promotes collaboration among DNA repair factors to support ALT telomere maintenance without PML. Given the promising effects of SUMOylation inhibitors in cancer treatment, our findings suggest their potential use in perturbing telomere maintenance in ALT cancer cells.
Asunto(s)
Reparación del ADN , Proteína de la Leucemia Promielocítica , Sumoilación , Homeostasis del Telómero , Telómero , Humanos , Proteína de la Leucemia Promielocítica/metabolismo , Proteína de la Leucemia Promielocítica/genética , Telómero/metabolismo , Línea Celular Tumoral , Proteína SUMO-1/metabolismo , Proteína SUMO-1/genética , Proteína Recombinante y Reparadora de ADN Rad52/metabolismo , Proteína Recombinante y Reparadora de ADN Rad52/genética , Línea Celular , Proteínas Modificadoras Pequeñas Relacionadas con Ubiquitina/metabolismo , Proteínas Modificadoras Pequeñas Relacionadas con Ubiquitina/genéticaRESUMEN
Promyelocytic leukemia protein (PML), a tumor suppressor protein, plays a key role in cell cycle regulation, apoptosis, senescence and cellular metabolism. Here, we report that PML promotes apoptosis and ferroptosis. Our data showed that PML over-expression inhibited cell proliferation and migration. PML over-expression increased apoptotic cells, nuclear condensation and the loss of mitochondrial membrane potential, accompanied by regulation of Bcl-2 family proteins and reactive oxygen species (ROS) level, suggesting that PML enhanced apoptosis. Meanwhile, PML over-expression not only increased lipid ROS accumulation and Malondialdehyde (MDA) content but also downregulated solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) expression, indicating that PML enhanced ferroptosis. Additionally, knockdown of p53 attenuated the effect of PML on SLC7A11 and GPX4, and inhibited the increase of lipid ROS and ROS by PML over-expression. Moreover, translocation of PML from nucleus to cytoplasm not only promoted apoptosis and ferroptosis, but also inhibited cell proliferation. Taken together, PML promotes apoptosis and ferroptosis, in which the mediation of p53 and the nuclear export of PML play important roles.
Asunto(s)
Transporte Activo de Núcleo Celular , Sistema de Transporte de Aminoácidos y+ , Apoptosis , Proliferación Celular , Ferroptosis , Fosfolípido Hidroperóxido Glutatión Peroxidasa , Proteína de la Leucemia Promielocítica , Proteína p53 Supresora de Tumor , Humanos , Sistema de Transporte de Aminoácidos y+/metabolismo , Sistema de Transporte de Aminoácidos y+/genética , Línea Celular Tumoral , Movimiento Celular , Núcleo Celular/metabolismo , Potencial de la Membrana Mitocondrial , Fosfolípido Hidroperóxido Glutatión Peroxidasa/metabolismo , Proteína de la Leucemia Promielocítica/metabolismo , Proteína de la Leucemia Promielocítica/genética , Especies Reactivas de Oxígeno/metabolismo , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Clear-cell renal cell carcinoma (ccRCC), the major subtype of RCC, is frequently diagnosed at late/metastatic stage with 13% 5-year disease-free survival. Functional inactivation of the wild-type p53 protein is implicated in ccRCC therapy resistance, but the detailed mechanisms of p53 malfunction are still poorly characterized. Thus, a better understanding of the mechanisms of disease progression and therapy resistance is required. Here, we report a novel ccRCC dependence on the promyelocytic leukemia (PML) protein. We show that PML is overexpressed in ccRCC and that PML depletion inhibits cell proliferation and relieves pathologic features of anaplastic disease in vivo. Mechanistically, PML loss unleashed p53-dependent cellular senescence thus depicting a novel regulatory axis to limit p53 activity and senescence in ccRCC. Treatment with the FDA-approved PML inhibitor arsenic trioxide induced PML degradation and p53 accumulation and inhibited ccRCC expansion in vitro and in vivo. Therefore, by defining non-oncogene addiction to the PML gene, our work uncovers a novel ccRCC vulnerability and lays the foundation for repurposing an available pharmacological intervention to restore p53 function and chemosensitivity.
Asunto(s)
Carcinoma de Células Renales , Senescencia Celular , Neoplasias Renales , Proteína de la Leucemia Promielocítica , Proteína p53 Supresora de Tumor , Proteína de la Leucemia Promielocítica/metabolismo , Proteína de la Leucemia Promielocítica/genética , Carcinoma de Células Renales/metabolismo , Carcinoma de Células Renales/patología , Carcinoma de Células Renales/genética , Carcinoma de Células Renales/tratamiento farmacológico , Humanos , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/genética , Senescencia Celular/efectos de los fármacos , Animales , Neoplasias Renales/metabolismo , Neoplasias Renales/patología , Neoplasias Renales/genética , Neoplasias Renales/tratamiento farmacológico , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Trióxido de Arsénico/farmacología , RatonesRESUMEN
Orphan nuclear receptors (NRs), such as COUP-TF1, COUP-TF2, EAR2, TR2 and TR4, are implicated in telomerase-negative cancers that maintain their telomeres through the alternative lengthening of telomeres (ALT) mechanism. However, how telomere association of orphan NRs is involved in ALT activation remains unclear. Here, we demonstrate that telomeric tethering of orphan NRs in human fibroblasts initiates formation of ALT-associated PML bodies (APBs) and features of ALT activity, including ALT telomere DNA synthesis, telomere sister chromatid exchange, and telomeric C-circle generation, suggesting de novo ALT induction. Overexpression of orphan NRs exacerbates ALT phenotypes in ALT cells, while their depletion limits ALT. Orphan NRs initiate ALT via the zinc finger protein 827, suggesting the involvement of chromatin structure alterations for ALT activation. Furthermore, we found that orphan NRs and deficiency of the ALT suppressor ATRX-DAXX complex operate in concert to promote ALT activation. Moreover, PML depletion by gene knockout or arsenic trioxide treatment inhibited ALT induction in fibroblasts and ALT cancer cells, suggesting that APB formation underlies the orphan NR-induced ALT activation. Importantly, arsenic trioxide administration abolished APB formation and features of ALT activity in ALT cancer cell line-derived mouse xenografts, suggesting its potential for further therapeutic development to treat ALT cancers.
Asunto(s)
Fibroblastos , Proteína de la Leucemia Promielocítica , Homeostasis del Telómero , Humanos , Animales , Proteína de la Leucemia Promielocítica/metabolismo , Proteína de la Leucemia Promielocítica/genética , Ratones , Fibroblastos/metabolismo , Telómero/metabolismo , Telómero/genética , Proteína Nuclear Ligada al Cromosoma X/genética , Proteína Nuclear Ligada al Cromosoma X/metabolismo , Proteínas Co-Represoras/genética , Proteínas Co-Represoras/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Intercambio de Cromátides Hermanas , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Línea Celular Tumoral , Trióxido de Arsénico/farmacología , Chaperonas MolecularesRESUMEN
Golgin tethers are known to mediate vesicular transport in the secretory pathway, whereas it is relatively unknown whether they may mediate cellular stress response within the cell. Here, we describe a cellular stress response during heat shock stress via SUMOylation of a Golgin tether, Golgin45. We found that Golgin45 is a SUMOylated Golgin via SUMO1 under steady state condition. Upon heat shock stress, the Golgin enters the nucleus by interacting with Importin-ß2 and gets further modified by SUMO3. Importantly, SUMOylated Golgin45 appears to interact with PML and SUMO-deficient Golgin45 mutant functions as a dominant negative for PML-NB formation during heat shock stress, suppressing transcription of lipid metabolism genes. These results indicate that Golgin45 may play a role in heat stress response by transcriptional regulation of lipid metabolism genes in SUMOylation-dependent fashion.
Asunto(s)
Respuesta al Choque Térmico , Metabolismo de los Lípidos , Sumoilación , Ubiquitinas , Humanos , Metabolismo de los Lípidos/genética , Respuesta al Choque Térmico/genética , Regulación de la Expresión Génica , Proteína de la Leucemia Promielocítica/metabolismo , Proteína de la Leucemia Promielocítica/genética , Células HeLa , Proteína SUMO-1/metabolismo , Proteína SUMO-1/genética , Proteínas Modificadoras Pequeñas Relacionadas con Ubiquitina/metabolismo , Proteínas Modificadoras Pequeñas Relacionadas con Ubiquitina/genética , Células HEK293 , Transcripción Genética , beta Carioferinas/metabolismo , beta Carioferinas/genéticaRESUMEN
In the seemingly well-researched field of vascular research, there are still many underestimated factors and molecular mechanisms. In recent years, SUMOylation has become increasingly important. SUMOylation is a post-translational modification in which small ubiquitin-related modifiers (SUMO) are covalently attached to target proteins. Sites where these SUMO modification processes take place in the cell nucleus are PML nuclear bodies (PML-NBs) - multiprotein complexes with their essential main component and organizer, the PML protein. PML and SUMO, either alone or as partners, influence a variety of cellular processes, including regulation of transcription, senescence, DNA damage response and defence against microorganisms, and are involved in innate immunity and inflammatory responses. They also play an important role in maintaining homeostasis in the vascular system and in pathological processes leading to the development and progression of cardiovascular diseases. This review summarizes information about the function of SUMO(ylation) and PML(-NBs) in the human vasculature from angiogenesis to disease and highlights their clinical potential as drug targets.
Asunto(s)
Proteínas Nucleares , Proteína de la Leucemia Promielocítica , Sumoilación , Factores de Transcripción , Humanos , Proteína de la Leucemia Promielocítica/metabolismo , Proteínas Nucleares/metabolismo , Factores de Transcripción/metabolismo , Animales , Proteínas Supresoras de Tumor/metabolismo , Proteínas Modificadoras Pequeñas Relacionadas con Ubiquitina/metabolismo , Enfermedades Cardiovasculares/metabolismo , Enfermedades Cardiovasculares/patologíaRESUMEN
The underlying mechanism(s) by which the PML::RARA fusion protein initiates acute promyelocytic leukemia is not yet clear. We defined the genomic binding sites of PML::RARA in primary mouse and human hematopoietic progenitor cells with V5-tagged PML::RARA, using anti-V5-PML::RARA chromatin immunoprecipitation sequencing and CUT&RUN approaches. Most genomic PML::RARA binding sites were found in regions that were already chromatin-accessible (defined by ATAC-seq) in unmanipulated, wild-type promyelocytes, suggesting that these regions are "open" prior to PML::RARA expression. We found that GATA binding motifs, and the direct binding of the chromatin "pioneering factor" GATA2, were significantly enriched near PML::RARA binding sites. Proximity labeling studies revealed that PML::RARA interacts with ~250 proteins in primary mouse hematopoietic cells; GATA2 and 33 others require PML::RARA binding to DNA for the interaction to occur, suggesting that binding to their cognate DNA target motifs may stabilize their interactions. In the absence of PML::RARA, Gata2 overexpression induces many of the same epigenetic and transcriptional changes as PML::RARA. These findings suggested that PML::RARA may indirectly initiate its transcriptional program by activating Gata2 expression: Indeed, we demonstrated that inactivation of Gata2 prior to PML::RARA expression prevented its ability to induce self-renewal. These data suggested that GATA2 binding creates accessible chromatin regions enriched for both GATA and Retinoic Acid Receptor Element motifs, where GATA2 and PML::RARA can potentially bind and interact with each other. In turn, PML::RARA binding to DNA promotes a feed-forward transcriptional program by positively regulating Gata2 expression. Gata2 may therefore be required for PML::RARA to establish its transcriptional program.
Asunto(s)
Factor de Transcripción GATA2 , Células Madre Hematopoyéticas , Proteínas de Fusión Oncogénica , Animales , Humanos , Ratones , Sitios de Unión , Autorrenovación de las Células , Cromatina/metabolismo , ADN/metabolismo , Factor de Transcripción GATA2/metabolismo , Factor de Transcripción GATA2/genética , Células Madre Hematopoyéticas/metabolismo , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/patología , Proteínas de Fusión Oncogénica/metabolismo , Proteínas de Fusión Oncogénica/genética , Proteína de la Leucemia Promielocítica/metabolismo , Proteína de la Leucemia Promielocítica/genética , Unión Proteica , Receptor alfa de Ácido Retinoico/metabolismo , Receptor alfa de Ácido Retinoico/genéticaRESUMEN
The alternative splicing of PML precursor mRNA gives rise to various PML isoforms, yet their expression profile in breast cancer cells remains uncharted. We discovered that PML1 is the most abundant isoform in all breast cancer subtypes, and its expression is associated with unfavorable prognosis in estrogen receptor-positive (ER+) breast cancers. PML depletion reduces cell proliferation, invasion, and stemness, while heterologous PML1 expression augments these processes and fuels tumor growth and resistance to fulvestrant, an FDA-approved drug for ER+ breast cancer, in a mouse model. Moreover, PML1, rather than the well-known tumor suppressor isoform PML4, rescues the proliferation of PML knockdown cells. ChIP-seq analysis reveals significant overlap between PML-, ER-, and Myc-bound promoters, suggesting their coordinated regulation of target gene expression, including genes involved in breast cancer stem cells (BCSCs), such as JAG1, KLF4, YAP1, SNAI1, and MYC. Loss of PML reduces BCSC-related gene expression, and exogenous PML1 expression elevates their expression. Consistently, PML1 restores the association of PML with these promoters in PML-depleted cells. We identified a novel association between PML1 and WDR5, a key component of H3K4 methyltransferase (HMTs) complexes that catalyze H3K4me1 and H3K4me3. ChIP-seq analyses showed that the loss of PML1 reduces H3K4me3 in numerous loci, including BCSC-associated gene promoters. Additionally, PML1, not PML4, re-establishes the H3K4me3 mark on these promoters in PML-depleted cells. Significantly, PML1 is essential for recruiting WDR5, MLL1, and MLL2 to these gene promoters. Inactivating WDR5 by knockdown or inhibitors phenocopies the effects of PML1 loss, reducing BCSC-related gene expression and tumorsphere formation and enhancing fulvestrant's anticancer activity. Our findings challenge the conventional understanding of PML as a tumor suppressor, redefine its role as a promoter of tumor growth in breast cancer, and offer new insights into the unique roles of PML isoforms in breast cancer.
Asunto(s)
Neoplasias de la Mama , Histonas , Factor 4 Similar a Kruppel , Células Madre Neoplásicas , Proteína de la Leucemia Promielocítica , Receptores de Estrógenos , Humanos , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Neoplasias de la Mama/genética , Femenino , Proteína de la Leucemia Promielocítica/metabolismo , Proteína de la Leucemia Promielocítica/genética , Animales , Receptores de Estrógenos/metabolismo , Receptores de Estrógenos/genética , Ratones , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Histonas/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Regulación Neoplásica de la Expresión GénicaRESUMEN
Promyelocytic leukemia (PML) nuclear bodies, membrane-less organelles in the nucleus, play a crucial role in cellular homeostasis. These dynamic structures result from the assembly of scaffolding PML proteins and various partners. Recent crystal structure analyses revealed essential self-interacting domains, while liquid-liquid phase separation contributes to their formation. PML bodies orchestrate post-translational modifications, particularly stress-induced SUMOylation, impacting target protein functions. Serving as hubs in multiple signaling pathways, they influence cellular processes like senescence. Dysregulation of PML expression contributes to diseases, including cancer, highlighting their significance. Therapeutically, PML bodies are promising targets, exemplified by successful acute promyelocytic leukemia treatment with arsenic trioxide and retinoic acid restoring PML bodies. Understanding their functions illuminates both normal and pathological cellular physiology, guiding potential therapies. This review explores recent advancements in PML body biogenesis, biochemical activity, and their evolving biological roles.
Asunto(s)
Leucemia Promielocítica Aguda , Cuerpos Nucleares de la Leucemia Promielocítica , Humanos , Proteínas Nucleares/metabolismo , Proteína de la Leucemia Promielocítica/genética , Proteína de la Leucemia Promielocítica/metabolismo , Factores de Transcripción/química , Factores de Transcripción/metabolismo , Leucemia Promielocítica Aguda/tratamiento farmacológico , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patologíaRESUMEN
Albeit N1-Methyladenosine (m1A) RNA modification represents an important regulator of RNA metabolism, the role of m1A modification in carcinogenesis remains enigmatic. Herein, we found that histone lactylation enhances ALKBH3 expression and simultaneously attenuates the formation of tumor-suppressive promyelocytic leukemia protein (PML) condensates by removing the m1A methylation of SP100A, promoting the malignant transformation of cancers. First, ALKBH3 is specifically upregulated in high-risk ocular melanoma due to excessive histone lactylation levels, referring to m1A hypomethylation status. Moreover, the multiomics analysis subsequently identified that SP100A, a core component for PML bodies, serves as a downstream candidate target for ALKBH3. Therapeutically, the silencing of ALKBH3 exhibits efficient therapeutic efficacy in melanoma both in vitro and in vivo, which could be reversed by the depletion of SP100A. Mechanistically, we found that YTHDF1 is responsible for recognition of the m1A methylated SP100A transcript, which increases its RNA stability and translational efficacy. Conclusively, we initially demonstrated that m1A modification is necessary for tumor suppressor gene expression, expanding the current understandings of dynamic m1A function during tumor progression. In addition, our results indicate that lactylation-driven ALKBH3 is essential for the formation of PML nuclear condensates, which bridges our knowledge of m1A modification, metabolic reprogramming, and phase-separation events.
Asunto(s)
Dioxigenasa Dependiente de Alfa-Cetoglutarato, Homólogo 3 de AlkB , Antígenos Nucleares , Autoantígenos , Neoplasias del Ojo , Histonas , Melanoma , Humanos , Dioxigenasa Dependiente de Alfa-Cetoglutarato, Homólogo 3 de AlkB/metabolismo , Desmetilación , Metilación de ADN , Histonas/genética , Histonas/metabolismo , Proteína de la Leucemia Promielocítica/genética , Proteína de la Leucemia Promielocítica/metabolismo , ARN/metabolismo , Factores de Transcripción/metabolismo , Antígenos Nucleares/metabolismo , Autoantígenos/metabolismo , Neoplasias del Ojo/metabolismoRESUMEN
Nuclear bodies (NBs) are dynamic structures present in eukaryotic cell nuclei. They are not bounded by membranes and are often considered biomolecular condensates, defined structurally and functionally by the localisation of core components. Nuclear architecture can be reorganised during normal cellular processes such as the cell cycle as well as in response to cellular stress. Many plant and animal viruses target their proteins to NBs, in some cases triggering their structural disruption and redistribution. Although not all such interactions have been well characterised, subversion of NBs and their functions may form a key part of the life cycle of eukaryotic viruses that require the nucleus for their replication. This review will focus on Cajal bodies (CBs) and the viruses that target them. Since CBs are dynamic structures, other NBs (principally nucleoli and promyelocytic leukaemia, PML and bodies), whose components interact with CBs, will also be considered. As well as providing important insights into key virus-host cell interactions, studies on Cajal and associated NBs may identify novel cellular targets for development of antiviral compounds.
Asunto(s)
Virosis , Virus , Animales , Proteínas Nucleares/metabolismo , Cuerpos Enrollados/metabolismo , Núcleo Celular , Virus/metabolismo , Virosis/metabolismo , Proteína de la Leucemia Promielocítica/metabolismoRESUMEN
The formation and function of membrane-less organelles (MLOs) is one of the main driving forces in the molecular life of the cell. These processes are based on the separation of biopolymers into phases regulated by multiple specific and nonspecific inter- and intramolecular interactions. Among the realm of MLOs, a special place is taken by the promyelocytic leukemia nuclear bodies (PML-NBs or PML bodies), which are the intranuclear compartments involved in the regulation of cellular metabolism, transcription, the maintenance of genome stability, responses to viral infection, apoptosis, and tumor suppression. According to the accepted models, specific interactions, such as SUMO/SIM, the formation of disulfide bonds, etc., play a decisive role in the biogenesis of PML bodies. In this work, a number of bioinformatics approaches were used to study proteins found in the proteome of PML bodies for their tendency for spontaneous liquid-liquid phase separation (LLPS), which is usually caused by weak nonspecific interactions. A total of 205 proteins found in PML bodies have been identified. It has been suggested that UBC9, P53, HIPK2, and SUMO1 can be considered as the scaffold proteins of PML bodies. It was shown that more than half of the proteins in the analyzed proteome are capable of spontaneous LLPS, with 85% of the analyzed proteins being intrinsically disordered proteins (IDPs) and the remaining 15% being proteins with intrinsically disordered protein regions (IDPRs). About 44% of all proteins analyzed in this study contain SUMO binding sites and can potentially be SUMOylated. These data suggest that weak nonspecific interactions play a significantly larger role in the formation and biogenesis of PML bodies than previously expected.
Asunto(s)
Cuerpos Nucleares de la Leucemia Promielocítica , Proteoma , Proteína de la Leucemia Promielocítica/genética , Proteína de la Leucemia Promielocítica/química , Proteína de la Leucemia Promielocítica/metabolismo , Proteoma/metabolismo , Prevalencia , Separación de Fases , SumoilaciónRESUMEN
Abstract The promyelocytic leukemia (PML) gene encoded PML protein as a tumor suppressor protein, plays important roles in the occurrence and development of various cancers including acute promyelocytic leukemia. Recent studies have indicated that there are a variety of post-translational modifications of the PML protein, such as SUMOylation, ubiquitination, phosphorylation, and acetylation in cells. These modifications of the PML protein can directly affect the formation of PML nuclear bodies (PML-NBs), repair DNA damage, and modulate cell apoptosis. Furthermore, the abnormal modifications of PML not only result in the occurrence of hematopoietic tumors, but also are closely related to the drug-resistance of cancer. Therefore, investigating the post-translational modifications of PML is significant to uncover the mechanism of formation and functions of PML-NBs, thus contributing to the prevention and treatment of related hematopoietic tumors. In this review, the characteristics of the post-translational modifications of PML protein and the relationship between these modifications and functions of PML-NBs are summarized so as to provide the potential targets for the treatment of related cancers.
Asunto(s)
Humanos , Cuerpos de Inclusión Intranucleares , Leucemia Promielocítica Aguda , Proteínas Nucleares , Proteína de la Leucemia Promielocítica , Procesamiento Proteico-PostraduccionalRESUMEN
Bromodomain-containing 4 (BRD4) has been considered as an important requirement for disease maintenance and an attractive therapeutic target for cancer therapy. This protein can be targeted by JQ1, a selective small-molecule inhibitor. However, few studies have investigated whether BRD4 influenced acute promyelocytic leukemia (APL), and whether BRD4 had interaction with promyelocytic leukemia-retinoic acid receptor α (PML/RARα) fusion protein to some extent. Results from cell viability assay, cell cycle analysis, and Annexin-V/PI analysis indicated that JQ1 inhibited the growth of NB4 cells, an APL-derived cell line, and induced NB4 cell cycle arrest at G1 and apoptosis. Then, we used co-immunoprecipitation (co-IP) assay and immunoblot to demonstrate the endogenous interaction of BRD4 and PML/RARα in NB4 cells. Moreover, downregulation of PML/RARα at the mRNA and protein levels was observed upon JQ1 treatment. Furthermore, results from the RT-qPCR, ChIP-qPCR, and re-ChIP-qPCR assays showed that BRD4 and PML/RARα co-existed on the same regulatory regions of their target genes. Hence, we showed a new discovery of the interaction of BRD4 and PML/RARα, as well as the decline of PML/RARα expression, under JQ1 treatment.
Asunto(s)
Humanos , Apoptosis , Azepinas , Farmacología , Diferenciación Celular , Regulación hacia Abajo , Regulación Neoplásica de la Expresión Génica , Leucemia Promielocítica Aguda , Quimioterapia , Genética , Proteínas Nucleares , Genética , Proteína de la Leucemia Promielocítica , Genética , ARN Mensajero , Genética , Receptor alfa de Ácido Retinoico , Genética , Factores de Transcripción , Genética , Triazoles , Farmacología , Células Tumorales CultivadasRESUMEN
Promyelocytic leukemia (PML) protein, a tumor suppressor, plays an important role in patients with acute promyelocytic leukemia (APL) receiving arsenic trioxide (AsO) therapy. APL is a M3 subtype of acute myeloid leukemia (AML), which is characterized by expression of PML-RARα (P/R) fusion protein, leading to the oncogenesis. AsO is currently used as the first-line drug for patients with APL, and the mechanism may be:AsO directly binds to PML part of P/R protein and induces multimerization of related proteins, which further recruits different functional proteins to reform PML nuclear bodies (PML-NBs), and finally it degraded by SUMOylation and ubiquitination proteasomal pathway. Gene mutations may lead to relapse and drug resistance after AsO treatment. In this review, we discuss the structure and function of PML proteins; the pathogenesis of APL induced by P/R fusion protein; the involvement of PML protein in treatment of APL patient with AsO; and explain how PML protein mutations could cause resistance to AsO therapy.
Asunto(s)
Humanos , Antineoplásicos , Usos Terapéuticos , Trióxido de Arsénico , Usos Terapéuticos , Resistencia a Antineoplásicos , Genética , Leucemia Promielocítica Aguda , Quimioterapia , Mutación , Proteínas de Fusión Oncogénica , Metabolismo , Proteína de la Leucemia Promielocítica , Química , Genética , MetabolismoRESUMEN
<p><b>OBJECTIVE</b>To investigate the effects of single heat stress treatment on spermatogenic cells in mice.</p><p><b>METHODS</b>We randomly divided 36 C57 male mice into a control and a heat stress treatment group and submerged the lower part of the torso in water at 25 °C and 43 °C, respectively, both for 15 minutes. At 1, 7, and 14 days after treatment, we obtained the testicular organ indexes, observed the changes in testicular morphology by HE staining, and determined the location and expression levels of the promyelocytic leukemia zinc finger (PLZF) and synaptonemal comlex protein-3 (SCP-3) in the testis tissue by immunohistochemistry and Western blot.</p><p><b>RESULTS</b>The testicular organ index was significantly lower in the heat stress treatment than in the control group (P < 0.05). Compared with the controls, the heat shock-treated mice showed loosely arranged spermatogenic cells scattered in the seminiferous tubules at 1 day after heat stress treatment, atrophied, loosely arranged and obviously reduced number of spermatogenic cells at 7 days, and relatively closely arranged seminiferous tubules and increased number and layers of spermatogenic cells at 14 days. The number of SCP-3 labelled spermatocytes obviously decreased in the heat stress-treated animals at 1 and 7 days and began to increase at 14 days. The PLZF protein expression was significantly reduced in the heat stress treatment group at 1 day as compared with that in the control (0.19 ± 0.12 vs 0.64 ± 0.03, P < 0.01), but elevated to 0.77 ± 0.02 at 7 and 14 days, even remarkably higher than in the control animals (P < 0.01).</p><p><b>CONCLUSION</b>Heat stress treatment can induce short-term dyszoospermia in mice, which can be recovered with the prolonged time after treatment.</p>
Asunto(s)
Animales , Masculino , Ratones , Western Blotting , Calor , Inmunohistoquímica , Proteínas Nucleares , Metabolismo , Proteína de la Leucemia Promielocítica , Túbulos Seminíferos , Biología Celular , Espermatocitos , Biología Celular , Patología , Testículo , Metabolismo , Factores de Transcripción , Metabolismo , Proteínas Supresoras de Tumor , MetabolismoRESUMEN
The promyelocytic leukemia (PML) was originally identified and named as acute promyelocytic leukaemia (APL) . The PML, encoded by PML gene, locates in the nuclear body (NB) and shuttles in the cell nucleus-cytoplasm, so that PML completes many regulation functions. There are many research on the function of nuclear PML, but in recent years the foreign data indicate that cytoplasmic PML gene plays an important role in hematologic malignancies and solid tumors. In this article, the biological functions of PML gene in cytoplasm are reviewed.
Asunto(s)
Humanos , Citoplasma , Genética , Leucemia Promielocítica Aguda , Genética , Proteínas Nucleares , Genética , Proteína de la Leucemia Promielocítica , Factores de Transcripción , Genética , Proteínas Supresoras de Tumor , GenéticaRESUMEN
<p><b>OBJECTIVE</b>To investigate the expression of promyelocytic leukaemia (PML) protein of PML protein in Bowen's disease (BD), skin squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) and explore the role of PML in the pathogenesis of these diseases.</p><p><b>METHODS</b>PML protein in normal skin tissues and lesions of Bowen's disease, SCC and BCC were detected with immunohistochemistry.</p><p><b>RESULTS</b>Normal skin tissues did not express PML protein. In BCC, PML showed rather low expressions in the skin lesions (8.69% in cell nuclei and 4.35% in cytoplasm). The lesions in BD and SCC (grade I and II) showed obvious overexpression of PML protein in the cell nuclei and cytoplasm, and its expression in the cell nuclei of these lesions was significantly higher than that in grade III-IV SCC.</p><p><b>CONCLUSION</b>PML protein may play an important role in the early stage of SCC, and its overexpression may contribute to the carcinogenesis and metastasis of SCC.</p>
Asunto(s)
Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Bowen , Metabolismo , Patología , Carcinoma Basocelular , Metabolismo , Patología , Carcinoma de Células Escamosas , Metabolismo , Patología , Proteínas Nucleares , Metabolismo , Proteína de la Leucemia Promielocítica , Neoplasias Cutáneas , Metabolismo , Patología , Factores de Transcripción , Metabolismo , Proteínas Supresoras de Tumor , MetabolismoRESUMEN
<p><b>OBJECTIVE</b>To investigate the effects of topical treatment with adenovirus-mediated promyelocytic leukemia gene (PML) gene in a psoriasis-like mouse model.</p><p><b>METHODS</b>The effect of adenovirus-mediated PML gene on the granular layer of mouse tail scale epidermis and epithelial mitosis were observed on longitudinal histological sections prepared from the tail skin and vaginal epithelium of the mice.</p><p><b>RESULTS</b>Adenovirus-mediated PML gene significantly inhibited mitosis of mouse vaginal epithelial cells and promoted the formation of granular layer in mouse tail scale epidermis.</p><p><b>CONCLUSION</b>The therapeutic effect of PML gene in the psoriasis-like mouse model may be associated with increased granular cells and suppressed epidemic cell proliferation.</p>