Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 85
Filtrar
1.
Proc Natl Acad Sci U S A ; 121(29): e2401834121, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-38976739

RESUMO

Lung adenocarcinoma (LUAD) is the leading cause of cancer-related death worldwide, but the underlying molecular mechanisms remain largely unclear. The transcription factor (TF) specificity protein 1 (SP1) plays a crucial role in the development of various cancers, including LUAD. Recent studies have indicated that master TFs may form phase-separated macromolecular condensates to promote super-enhancer (SE) assembly and oncogene expression. In this study, we demonstrated that SP1 undergoes phase separation and that its zinc finger 3 in the DNA-binding domain is essential for this process. Through Cleavage Under Targets & Release Using Nuclease (CUT&RUN) using antibodies against SP1 and H3K27ac, we found a significant correlation between SP1 enrichment and SE elements, identified the regulator of the G protein signaling 20 (RGS20) gene as the most likely target regulated by SP1 through SE mechanisms, and verified this finding using different approaches. The oncogenic activity of SP1 relies on its phase separation ability and RGS20 gene activation, which can be abolished by glycogen synthase kinase J4 (GSK-J4), a demethylase inhibitor. Together, our findings provide evidence that SP1 regulates its target oncogene expression through phase separation and SE mechanisms, thereby promoting LUAD cell progression. This study also revealed an innovative target for LUAD therapies through intervening in SP1-mediated SE formation.


Assuntos
Adenocarcinoma de Pulmão , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares , Proteínas RGS , Fator de Transcrição Sp1 , Fator de Transcrição Sp1/metabolismo , Fator de Transcrição Sp1/genética , Humanos , Adenocarcinoma de Pulmão/metabolismo , Adenocarcinoma de Pulmão/patologia , Adenocarcinoma de Pulmão/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/genética , Proteínas RGS/metabolismo , Proteínas RGS/genética , Linhagem Celular Tumoral , Animais , Elementos Facilitadores Genéticos , Progressão da Doença , Camundongos , Separação de Fases
2.
Nucleic Acids Res ; 50(9): 4917-4937, 2022 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-35390165

RESUMO

As an oncogenic transcription factor, Yin Yang 1 (YY1) regulates enhancer and promoter connection. However, gaps still exist in understanding how YY1 coordinates coactivators and chromatin enhancer elements to assemble enhancers and super-enhancers. Here, we demonstrate that a histidine cluster in YY1's transactivation domain is essential for its formation of phase separation condensates, which can be extended to additional proteins. The histidine cluster is also required for YY1-promoted cell proliferation, migration, clonogenicity and tumor growth. YY1-rich nuclear puncta contain coactivators EP300, BRD4, MED1 and active RNA polymerase II, and colocalize with histone markers of gene activation, but not that of repression. Furthermore, YY1 binds to the consensus motifs in the FOXM1 promoter to activate its expression. Wild-type YY1, but not its phase separation defective mutant, connects multiple enhancer elements and the FOXM1 promoter to form an enhancer cluster. Consistently, fluorescent in situ hybridization (FISH) assays reveal the colocalization of YY1 puncta with both the FOXM1 gene locus and its nascent RNA transcript. Overall, this study demonstrates that YY1 activates target gene expression through forming liquid-liquid phase separation condensates to compartmentalize both coactivators and enhancer elements, and the histidine cluster of YY1 plays a determinant role in this regulatory mechanism.


Assuntos
Cromatina , Elementos Facilitadores Genéticos , Fator de Transcrição YY1 , Regulação da Expressão Gênica , Histidina/química , Hibridização in Situ Fluorescente , Proteínas Nucleares/metabolismo , Fator de Transcrição YY1/química , Fator de Transcrição YY1/metabolismo
3.
Int J Mol Sci ; 25(18)2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-39337671

RESUMO

Neurodegenerative diseases are the leading cause of human disability and immensely reduce patients' life span and quality. The diseases are characterized by the functional loss of neuronal cells and share several common pathogenic mechanisms involving the malfunction, structural distortion, or aggregation of multiple key regulatory proteins. Cellular phase separation is the formation of biomolecular condensates that regulate numerous biological processes, including neuronal development and synaptic signaling transduction. Aberrant phase separation may cause protein aggregation that is a general phenomenon in the neuronal cells of patients suffering neurodegenerative diseases. In this review, we summarize the pathological causes of common neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and Huntington's disease, among others. We discuss the regulation of key amyloidogenic proteins with an emphasis of their aberrant phase separation and aggregation. We also introduce the approaches as potential therapeutic strategies to ameliorate neurodegenerative diseases through intervening protein aggregation. Overall, this review consolidates the research findings of phase separation and aggregation caused by misfolded proteins in a context of neurodegenerative diseases.


Assuntos
Doenças Neurodegenerativas , Agregação Patológica de Proteínas , Humanos , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Agregação Patológica de Proteínas/metabolismo , Animais , Proteínas Amiloidogênicas/metabolismo , Proteínas Amiloidogênicas/química , Agregados Proteicos , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Separação de Fases
4.
Int J Mol Sci ; 25(3)2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38338812

RESUMO

Biosensors based on allosteric transcription factors have been widely used in synthetic biology. In this study, we utilized the Acinetobacter ADP1 transcription factor PobR to develop a biosensor activating the PpobA promoter when bound to its natural ligand, 4-hydroxybenzoic acid (4HB). To screen for PobR mutants responsive to 4-hydroxyphenylpyruvate(HPP), we developed a dual selection system in E. coli. The positive selection of this system was used to enrich PobR mutants that identified the required ligands. The following negative selection eliminated or weakened PobR mutants that still responded to 4HB. Directed evolution of the PobR library resulted in a variant where PobRW177R was 5.1 times more reactive to 4-hydroxyphenylpyruvate than PobRWT. Overall, we developed an efficient dual selection system for directed evolution of biosensors.


Assuntos
Técnicas Biossensoriais , Ácidos Fenilpirúvicos , Transativadores , Transativadores/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Fatores de Transcrição/metabolismo
5.
Int J Mol Sci ; 23(5)2022 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-35269825

RESUMO

Receptors are macromolecules that transmit information regulating cell proliferation, differentiation, migration and apoptosis, play key roles in oncogenic processes and correlate with the prognoses of cancer patients. Thus, targeting receptors to constrain cancer development and progression has gained widespread interest. Small molecule compounds of natural origin have been widely used as drugs or adjuvant chemotherapeutic agents in cancer therapies due to their activities of selectively killing cancer cells, alleviating drug resistance and mitigating side effects. Meanwhile, many natural compounds, including those targeting receptors, are still under laboratory investigation for their anti-cancer activities and mechanisms. In this review, we classify the receptors by their structures and functions, illustrate the natural compounds targeting these receptors and discuss the mechanisms of their anti-cancer activities. We aim to provide primary knowledge of mechanistic regulation and clinical applications of cancer therapies through targeting deregulated receptors.


Assuntos
Antineoplásicos , Neoplasias , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose , Humanos , Neoplasias/tratamento farmacológico , Oncogenes
6.
Int J Mol Sci ; 23(10)2022 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-35628304

RESUMO

In live cells, proteins and nucleic acids can associate together through multivalent interactions, and form relatively isolated phases that undertake designated biological functions and activities. In the past decade, liquid-liquid phase separation (LLPS) has gradually been recognized as a general mechanism for the intracellular organization of biomolecules. LLPS regulates the assembly and composition of dozens of membraneless organelles and condensates in cells. Due to the altered physiological conditions or genetic mutations, phase-separated condensates may undergo aberrant formation, maturation or gelation that contributes to the onset and progression of various diseases, including neurodegenerative disorders and cancers. In this review, we summarize the properties of different membraneless organelles and condensates, and discuss multiple phase separation-regulated biological processes. Based on the dysregulation and mutations of several key regulatory proteins and signaling pathways, we also exemplify how aberrantly regulated LLPS may contribute to human diseases.


Assuntos
Doenças Neurodegenerativas , Ácidos Nucleicos , Humanos , Proteínas/metabolismo
7.
World J Microbiol Biotechnol ; 38(6): 104, 2022 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-35501522

RESUMO

Hydroxy-mandelic acid (HMA) is widely applied in pharmaceuticals, food and cosmetics. In this study, we aimed to develop an allosteric transcription factors (aTFs) based biosensor for HMA. PobR, an aTF for HMA analog 4-hydroxybenzoic acid, was used to alter its selectivity and create novel aTFs responsive to HMA by directed evolution. We established a PobR mutant library with a capacity of 550,000 mutants using error-prone PCR and Megawhop PCR. Through our screening, two mutants were obtained with responsiveness to HMA. Analysis of each missense mutation indicating residues 122-126 were involved in its PobR ligand specificity. These results showed the effectiveness of directed evolution in switching the ligand specificity of a biosensor and improving HMA production.


Assuntos
Técnicas Biossensoriais , Fatores de Transcrição , Proteínas de Bactérias/genética , Técnicas Biossensoriais/métodos , Ligantes , Ácidos Mandélicos , Fatores de Transcrição/química , Fatores de Transcrição/genética
8.
Gene Ther ; 28(12): 697-717, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-32409746

RESUMO

The direct oncolytic effect of Newcastle disease virus (NDV) depends on the following two aspects: the susceptibility of cancer cells to virus infection and the ability of virus itself to lyse cancer cells. First, we investigate the susceptibility of cancer cells to NDV infection, HepG2, MDA-MB-231, and SH-SY5Y cells were susceptible, A549, MCF7, and LoVo cells were less susceptible. To investigate the molecular mechanism responsible for cancer cell susceptibility, transcriptome sequencing was carried out. We found that the levels of alpha-sialic acid acyltransferase were upregulated in MDA-MB-231 cells compared with MCF7 cells, and the interferon was downregulated. Second, to optimize the oncolytic capacity of the wild-type rClone30, a series of chimeric viruses rClone30-Anh(HN), rClone30-Anh(F), and rClone30-Anh(HN-F) were constructed by exchanging the HN gene, F gene or both of non-lytic rClone30 strain with lytic strain Anhinga. rClone30-Anh(F) and rClone30-Anh(HN-F) enhanced the oncolytic effect of the rClone30, and this enhancement is more obvious in the susceptible cells. The oncolytic mechanism of rClone30-Anh(F) was analyzed by transcriptome analyses, in comparison with rClone30, rClone30-Anh(F) upregulated the expression of ATG5, Beclin 1, and MAP1LC3B, thus activating autophagy and promoting the production of syncytia. In conclusion, our study provides a strategy to enhance the oncolytic effect of rClone30.


Assuntos
Neoplasias , Terapia Viral Oncolítica , Vírus Oncolíticos , Animais , Linhagem Celular Tumoral , Vírus da Doença de Newcastle/genética , Vírus Oncolíticos/genética , Replicação Viral
9.
Biochem Biophys Res Commun ; 561: 93-100, 2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-34020144

RESUMO

AKT1 plays a key role in cell growth and survival, and its activation in cancers is mediated by different mechanisms. In this study, we investigated the potential of G-quadruplex (G4) formation by multiple consecutive G-tracts in the AKT1 promoter and its 3'-UTR. In circular dichroism analyses, synthetic oligonucleotides based on these G-tract regions showed molar ellipticity peaks at specific wavelengths of G4 structures. We verified G4 forming potential of these oligonucleotides using dimethyl sulfate footprinting, gel-shift and immunostaining assays. In reporter assays, mutations of the G-tracts in either the promoter or the 3'-UTR of AKT1 reduced expression mediated by these G-rich regions, suggesting positive regulation of AKT1 gene expression by these G4 structures. Furthermore, SP1 bound to its consensus sites regardless of the presence of G4 motifs in the AKT1 promoter, and both the G4 motifs and SP1 binding sites were needed to reach the strongest promoter strength.


Assuntos
Quadruplex G , Neoplasias/genética , Neoplasias/patologia , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Regiões 3' não Traduzidas , Sítios de Ligação , Dicroísmo Circular/métodos , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias/metabolismo , Regiões Promotoras Genéticas
10.
RNA Biol ; 18(sup1): 318-336, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34291726

RESUMO

ABBREVIATIONS: ARF: alternative reading frame, that is, p14ARF, or CDKN2A (cyclin-dependent kinase inhibitor 2A); ß-gal: ß-galactosidase; CLIP-seq: crosslinking and immunoprecipitation-sequencing; DMTF1: the cyclin D binding myb-like transcription factor 1; ESS/ESE: exonic splicing silencer/enhancer; Ex: exon; FBS: fetal bovine serum; Gluc: Gaussia luciferase; hnRNPs: heterogeneous nuclear ribonucleoproteins; In: intron; ISS/ISE: intronic splicing silencer/enhancer; PBS: phosphate-buffered saline; PCR: polymerase chain reaction; PSI: percent-splice-in; qPCR: quantitative real-time PCR; RIP: RNA immunoprecipitation; RNAseq: RNA sequencing; RT: reverse transcription; SF1: splicing factor 1; SR: serine/arginine-rich proteins; SRSF5: serine and arginine-rich splicing factor 5; TCGA: the cancer genome atlas; UCSC: University of California, Santa Cruz. WT: Wild type.


Assuntos
Processamento Alternativo , Precursores de RNA/genética , Fatores de Processamento de RNA/metabolismo , Fatores de Processamento de Serina-Arginina/metabolismo , Fatores de Transcrição/genética , Sequência de Bases , Humanos , Precursores de RNA/metabolismo , Fatores de Processamento de RNA/genética , Homologia de Sequência , Fatores de Processamento de Serina-Arginina/genética , Fatores de Transcrição/metabolismo
11.
Exp Cell Res ; 394(2): 112158, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32610184

RESUMO

SNAIL1 is a key regulator of epithelial-mesenchymal transition (EMT) and its expression is associated with tumor progression and poor clinical prognosis of cancer patients. Compared to the studies of SNAIL1 stability and its transcriptional regulation, very limited knowledge is available regarding effective approaches to directly target SNAIL1. In this study, we revealed the potential regulation of SNAIL1 gene expression by G-quadruplex structures in its promoter. We first revealed that the negative strand of the SNAIL1 promoter contained a multi-G-tract region with high potential of forming G-quadruplex structures. In circular dichroism studies, the oligonucleotide based on this region showed characteristic molar ellipticity at specific wavelengths of G-quadruplex structures. We also utilized native polyacrylamide gel electrophoresis, gel-shift assays, immunofluorescent staining, dimethyl sulfate footprinting and chromatin immunoprecipitation studies to verify the G-quadruplex structures formed by the oligonucleotide. In reporter assays, disruption of G-quadruplex potential increased SNAIL1 promoter-mediated transcription, suggesting that G-quadruplexes played a negative role in SNAIL1 expression. In a DNA synthesis study, we detected G-quadruplex-mediated retardation in the SNAIL1 promoter replication. Consistently, we discovered that the G-quadruplex region of the SNAIL1 promoter is highly enriched for mutations, implicating the clinical relevance of G-quadruplexes to the altered SNAIL1 expression in cancer cells.


Assuntos
Replicação do DNA/genética , Quadruplex G , Regulação da Expressão Gênica , Regiões Promotoras Genéticas , Fatores de Transcrição da Família Snail/genética , Sequência de Bases , Dicroísmo Circular , DNA/biossíntese , Pegada de DNA , Genes Reporter , Genoma Humano , Humanos , Temperatura de Transição
12.
Int J Mol Sci ; 21(2)2020 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-31963946

RESUMO

Prostate cancer (PCa) is one of the most common cancers and the second leading cause of cancer-related death among men worldwide. Despite progresses in early diagnosis and therapeutic strategies, prognosis for patients with advanced PCa remains poor. Noteworthily, a unique feature of healthy prostate is its highest level of zinc content among all soft tissues in the human body, which dramatically decreases during prostate tumorigenesis. To date, several reviews have suggested antitumor activities of zinc and its potential as a therapeutic strategy of PCa. However, an overview about the role of zinc and its signaling in PCa is needed. Here, we review literature related to the content, biological function, compounds and clinical application of zinc in PCa. We first summarize zinc content in prostate tissue and sera of PCa patients with their clinical relevance. We then elaborate biological functions of zinc signaling in PCa on three main aspects, including cell proliferation, death and tumor metastasis. Finally, we discuss clinical applications of zinc-containing compounds and proteins involved in PCa signaling pathways. Based on currently available studies, we conclude that zinc plays a tumor suppressive role and can serve as a biomarker in PCa diagnosis and therapies.


Assuntos
Redes Reguladoras de Genes , Neoplasias da Próstata/metabolismo , Zinco/metabolismo , Proliferação de Células , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Metástase Neoplásica , Prognóstico , Transdução de Sinais , Zinco/sangue
14.
Exp Cell Res ; 369(1): 147-157, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29787736

RESUMO

Accumulating evidence suggests a key role of BAP1 in oncogenesis, but mechanisms regulating BAP1 gene expression remain unexplored. In this report, we revealed that the BAP1 promoter contains multiple G-tracts in its negative strand with high potential of forming G-quadruplex (G4) structures. In circular dichroism studies, synthesized oligonucleotides within these G-rich regions upstream the BAP1 transcription start site showed molar ellipticity at specific wavelengths characteristic of G4 structures. Analyses of these oligonucleotides by native polyacrylamide gel electrophoresis revealed formation of multiple types of G4 structures. In reporter assays, mutations or deletion of predicted G4 structures reduced BAP1 promoter activity. Additionally, DNA helicases CHD2 and CHD7 could reduce BAP1 promoter activity, likely through unwinding its G4 structures.


Assuntos
DNA Helicases/fisiologia , Proteínas de Ligação a DNA/fisiologia , Quadruplex G , Regiões Promotoras Genéticas , Proteínas Supressoras de Tumor/genética , Ubiquitina Tiolesterase/genética , Sequência de Bases , Dicroísmo Circular , DNA Helicases/metabolismo , Proteínas de Ligação a DNA/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Análise em Microsséries , Regiões Promotoras Genéticas/genética , Ligação Proteica , Deleção de Sequência , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/metabolismo , Ubiquitina Tiolesterase/química , Ubiquitina Tiolesterase/metabolismo
15.
Bioinformatics ; 33(20): 3286-3288, 2017 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-28633441

RESUMO

MOTIVATION: With the rapid development of Next-Generation Sequencing, a large amount of data is now available for bioinformatics research. Meanwhile, the presence of many pipeline frameworks makes it possible to analyse these data. However, these tools concentrate mainly on their syntax and design paradigms, and dispatch jobs based on users' experience about the resources needed by the execution of a certain step in a protocol. As a result, it is difficult for these tools to maximize the potential of computing resources, and avoid errors caused by overload, such as memory overflow. RESULTS: Here, we have developed BioQueue, a web-based framework that contains a checkpoint before each step to automatically estimate the system resources (CPU, memory and disk) needed by the step and then dispatch jobs accordingly. BioQueue possesses a shell command-like syntax instead of implementing a new script language, which means most biologists without computer programming background can access the efficient queue system with ease. AVAILABILITY AND IMPLEMENTATION: BioQueue is freely available at https://github.com/liyao001/BioQueue. The extensive documentation can be found at http://bioqueue.readthedocs.io. CONTACT: li_yao@outlook.com or gcsui@nefu.edu.cn. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Biologia Computacional/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Software , Documentação , Humanos , Análise de Sequência de RNA/métodos
16.
Mol Cell ; 39(2): 222-33, 2010 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-20670891

RESUMO

Dynamic histone H3K4 methylation is an important epigenetic component of transcriptional regulation. However, most of our current understanding of this histone mark is confined to the regulation of transcriptional initiation. We now show that human LSD2/KDM1b/AOF1, the human homolog of LSD1, is an H3K4me1/2 demethylase that specifically regulates histone H3K4 methylation within intragenic regions of its target genes. Genome-wide mapping reveals that LSD2 associates predominantly with the gene bodies of actively transcribed genes, but is markedly absent from promoters. Depletion of endogenous LSD2 results in an increase of H3K4me2 as well as a decrease of H3K9me2 at LSD2-binding sites and a consequent dysregulation of target gene transcription. Furthermore, characterization of the LSD2 complex reveals that LSD2 forms active complexes with euchromatic histone methyltransferases G9a and NSD3 as well as cellular factors involved in transcription elongation. These data provide a possible molecular mechanism linking LSD2 to transcriptional regulation after initiation.


Assuntos
Histona Desmetilases/metabolismo , Histonas/metabolismo , Processamento de Proteína Pós-Traducional/fisiologia , Transcrição Gênica/fisiologia , Sítios de Ligação , Células HeLa , Antígenos de Histocompatibilidade/genética , Antígenos de Histocompatibilidade/metabolismo , Histona Desmetilases/genética , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/genética , Humanos , Metilação , Complexos Multienzimáticos/genética , Complexos Multienzimáticos/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo
17.
Int J Mol Sci ; 19(5)2018 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-29757932

RESUMO

SOX7 is a transcription factor and acts as a tumor suppressor, but its target genes in cancers are poorly explored. We revealed SOX7-mediated gene expression profile in breast cancer cells using microarray chips and discovered multiple altered signaling pathways. When combinatorially analyzing the microarray data with a gene array dataset from 759 breast cancer patients, we identified four genes as potential targets of SOX7 and validated them by quantitative PCR and chromatin immunoprecipitation assays. Among these four genes, we determined that SOX7-activated SPRY1 and SLIT2, and SOX7-repressed TRIB3 and MTHFD2 could all differentially contribute to SOX7-mediated tumor suppression. Overall, we identified multiple cancer-related pathways mediated by SOX7 and for the first time revealed SOX7-regulated target genes in a cancer-relevant context.


Assuntos
Regulação Neoplásica da Expressão Gênica , Fatores de Transcrição SOXF/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Feminino , Expressão Gênica , Perfilação da Expressão Gênica , Genes Reporter , Humanos , Ligação Proteica , Reprodutibilidade dos Testes , Transcriptoma
18.
Int J Mol Sci ; 18(3)2017 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-28257090

RESUMO

Alternative pre-mRNA splicing is a crucial process that allows the generation of diversified RNA and protein products from a multi-exon gene. In tumor cells, this mechanism can facilitate cancer development and progression through both creating oncogenic isoforms and reducing the expression of normal or controllable protein species. We recently demonstrated that an alternative cyclin D-binding myb-like transcription factor 1 (DMTF1) pre-mRNA splicing isoform, DMTF1ß, is increasingly expressed in breast cancer and promotes mammary tumorigenesis in a transgenic mouse model. Aberrant pre-mRNA splicing is a typical event occurring for many cancer-related functional proteins. In this review, we introduce general aberrant pre-mRNA splicing in cancers and discuss its therapeutic application using our recent discovery of the oncogenic DMTF1 isoform as an example. We also summarize new insights in designing novel targeting strategies of cancer therapies based on the understanding of deregulated pre-mRNA splicing mechanisms.


Assuntos
Neoplasias da Mama/patologia , Neoplasias da Mama/terapia , Isoformas de Proteínas/genética , Fatores de Transcrição/genética , Processamento Alternativo/efeitos dos fármacos , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Neoplasias da Mama/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , Terapia de Alvo Molecular , Neoplasias/genética , Neoplasias/patologia , Neoplasias/terapia , Isoformas de Proteínas/efeitos dos fármacos
19.
J Pathol ; 236(1): 90-102, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25537728

RESUMO

Our recent work has indicated that the DMP1 locus on 7q21, encoding a haplo-insufficient tumour suppressor, is hemizygously deleted at a high frequency in breast cancer. The locus encodes DMP1α protein, an activator of the p53 pathway leading to cell cycle arrest and senescence, and two other functionally undefined isoforms, DMP1ß and DMP1γ. In this study, we show that the DMP1 locus is alternatively spliced in ∼30% of breast cancer cases with relatively decreased DMP1α and increased DMP1ß expression. RNA-seq analyses of a publicly available database showed significantly increased DMP1ß mRNA in 43-55% of human breast cancers, dependent on histological subtypes. Similarly, DMP1ß protein was found to be overexpressed in ∼60% of tumours relative to their surrounding normal tissue. Importantly, alteration of DMP1 splicing and DMP1ß overexpression were associated with poor clinical outcomes of the breast cancer patients, indicating that DMP1ß may have a biological function. Indeed, DMP1ß increased proliferation of non-tumourigenic mammary epithelial cells and knockdown of endogenous DMP1 inhibited breast cancer cell growth. To determine DMP1ß's role in vivo, we established MMTV-DMP1ß transgenic mouse lines. DMP1ß overexpression was sufficient to induce mammary gland hyperplasia and multifocal tumour lesions in mice at 7-18 months of age. The tumours formed were adenosquamous carcinomas with evidence of transdifferentiation and keratinized deposits. Overall, we identify alternative splicing as a mechanism utilized by cancer cells to modulate the DMP1 locus through diminishing DMP1α tumour suppressor expression, while simultaneously up-regulating the tumour-promoting DMP1ß isoform.


Assuntos
Neoplasias da Mama/metabolismo , Proliferação de Células/genética , Transformação Celular Neoplásica/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Fosfoproteínas/metabolismo , Fatores de Transcrição/metabolismo , Processamento Alternativo , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Progressão da Doença , Proteínas da Matriz Extracelular/genética , Feminino , Humanos , Glândulas Mamárias Humanas/patologia , Camundongos Transgênicos , Fosfoproteínas/genética , Fatores de Transcrição/genética
20.
Biochem Biophys Res Commun ; 445(1): 208-13, 2014 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-24508259

RESUMO

The mechanisms for regulation of the Inhibitor of Apoptosis (IAP) Survivin in cells undergoing stress associated with tumor development and the tumor microenvironment are not well understood. The stress response transcription factors HIF-1α and Yin Yang 1 (YY1) were hypothesized to contribute to the upregulation of Survivin in tumor cells. As expected, U2OS cells overexpressing HIF-1α showed a 2- to 3-fold transactivation when transfected. Surprisingly, when YY1 was overexpressed in this survivin promoter reporter system, luciferase expression was repressed 30- to 40-fold. YY1 involvement in survivin promoter repression was confirmed using siRNA directed against YY1. These studies showed that knockdown of YY1 releases the survivin promoter from the observed repression and leads to a 3- to 5-fold increase in promoter activity above basal levels. A U2OS cell line containing a stable YY1 Tet-off system was used to determine whether a temporal increase in YY1 expression affects Survivin protein levels. A low to moderate decrease in Survivin protein was observed 24h and 48h after Tet removal. Studies also confirmed that YY1 is capable of directly binding to the survivin promoter. Collectively, these findings identify novel basal transcriptional requirements of survivin gene expression which are likely to play important roles in the development of cancer and resistance to its treatment.


Assuntos
Regulação Neoplásica da Expressão Gênica , Proteínas Inibidoras de Apoptose/genética , Transcrição Gênica , Fator de Transcrição YY1/genética , Sequência de Bases , Sítios de Ligação/genética , Western Blotting , Linhagem Celular Tumoral , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Proteínas Inibidoras de Apoptose/metabolismo , Luciferases/genética , Luciferases/metabolismo , Dados de Sequência Molecular , Regiões Promotoras Genéticas/genética , Ligação Proteica , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Survivina , Fator de Transcrição YY1/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA