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1.
Nat Commun ; 11(1): 5007, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-33024116

RESUMO

p50, the mature product of NFKB1, is constitutively produced from its precursor, p105. Here, we identify BARD1 as a p50-interacting factor. p50 directly associates with the BARD1 BRCT domains via a C-terminal phospho-serine motif. This interaction is induced by ATR and results in mono-ubiquitination of p50 by the BARD1/BRCA1 complex. During the cell cycle, p50 is mono-ubiquitinated in S phase and loss of this post-translational modification increases S phase progression and chromosomal breakage. Genome-wide studies reveal a substantial decrease in p50 chromatin enrichment in S phase and Cycln E is identified as a factor regulated by p50 during the G1 to S transition. Functionally, interaction with BARD1 promotes p50 protein stability and consistent with this, in human cancer specimens, low nuclear BARD1 protein strongly correlates with low nuclear p50. These data indicate that p50 mono-ubiquitination by BARD1/BRCA1 during the cell cycle regulates S phase progression to maintain genome integrity.


Assuntos
Neoplasias da Mama/metabolismo , Ciclo Celular/fisiologia , Instabilidade Genômica , Subunidade p50 de NF-kappa B/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Sítios de Ligação , Neoplasias da Mama/mortalidade , Linhagem Celular Tumoral , Feminino , Fibroblastos , Humanos , Lisina/metabolismo , Camundongos , Subunidade p50 de NF-kappa B/genética , Neuroblastoma/metabolismo , Domínios Proteicos , Processamento de Proteína Pós-Traducional , Serina/metabolismo , Proteínas Supressoras de Tumor/genética , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
2.
PLoS Biol ; 18(9): e3000852, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32931487

RESUMO

Olfaction in most animals is mediated by neurons bearing cilia that are accessible to the environment. Olfactory sensory neurons (OSNs) in chordates usually have multiple cilia, each with a centriole at its base. OSNs differentiate from stem cells in the olfactory epithelium, and how the epithelium generates cells with many centrioles is not yet understood. We show that centrioles are amplified via centriole rosette formation in both embryonic development and turnover of the olfactory epithelium in adult mice, and rosette-bearing cells often have free centrioles in addition. Cells with amplified centrioles can go on to divide, with centrioles clustered at each pole. Additionally, we found that centrioles are amplified in immediate neuronal precursors (INPs) concomitant with elevation of mRNA for polo-like kinase 4 (Plk4) and SCL/Tal1-interrupting locus gene (Stil), key regulators of centriole duplication. These results support a model in which centriole amplification occurs during a transient state characterized by elevated Plk4 and Stil in early INP cells. These cells then go on to divide at least once to become OSNs, demonstrating that cell division with amplified centrioles, known to be tolerated in disease states, can occur as part of a normal developmental program.


Assuntos
Divisão Celular/fisiologia , Centríolos/fisiologia , Células-Tronco Neurais/citologia , Células-Tronco Neurais/fisiologia , Neurônios Receptores Olfatórios/fisiologia , Envelhecimento/fisiologia , Animais , Ciclo Celular/fisiologia , Células Cultivadas , Embrião de Mamíferos , Desenvolvimento Embrionário/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Córtex Olfatório/citologia , Córtex Olfatório/embriologia , Mucosa Olfatória/citologia , Mucosa Olfatória/embriologia , Mucosa Olfatória/ultraestrutura , Neurônios Receptores Olfatórios/citologia , Neurônios Receptores Olfatórios/ultraestrutura
3.
Int J Nanomedicine ; 15: 6201-6209, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32884270

RESUMO

Background: Unique properties of graphene and its derivatives make them attractive in the field of nanomedicine. However, the mass application of graphene might lead to side effects, which has not been properly addressed in previous studies, especially with regard to its effect on the cell cycle. Methods: The effect of two concentrations (100 and 200 µg/mL) of nano- and microsized graphene oxide (nGO and mGO) on apoptosis, cell cycle, and ROS generation was studied. The effect of both sizes on viability and genotoxicity of the embryonic fibroblast cell cycle was evaluated. MTT and flow cytometry were applied to evaluate the effects of graphene oxide (GO) nanosheets on viability of cells. Apoptosis and cell cycle were analyzed by flow cytometry. Results: The results of this study showed that GO disturbed the cell cycle and nGO impaired cell viability by inducing cell apoptosis. Interestingly, both nGO and mGO blocked the cell cycle in the S phase, which is a critical phase of the cell cycle. Upregulation of TP53-gene transcripts was also detected in both nGO- and mGO-treated cells compared to the control, especially at 200 µg/mL. DNA content of the treated cells increased; however, because of DNA degradation, its quality was decreased. Conclusion: In conclusion, graphene oxide at both nano- and micro-scale damages cell physiology and increases cell population in the S phase of the cell cycle.


Assuntos
Ciclo Celular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Grafite/farmacologia , Nanoestruturas/toxicidade , Animais , Apoptose/efeitos dos fármacos , Ciclo Celular/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Embrião de Mamíferos/citologia , Fibroblastos/citologia , Regulação da Expressão Gênica/efeitos dos fármacos , Grafite/toxicidade , Camundongos , Testes de Mutagenicidade , Espécies Reativas de Oxigênio/metabolismo , Proteína Supressora de Tumor p53/genética
4.
Nat Commun ; 11(1): 4075, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32796847

RESUMO

Hematopoietic ageing involves declining erythropoiesis and lymphopoiesis, leading to frequent anaemia and decreased adaptive immunity. How intrinsic changes to the hematopoietic stem cells (HSCs), an altered microenvironment and systemic factors contribute to this process is not fully understood. Here we use bone marrow stromal cells as sensors of age-associated changes to the bone marrow microenvironment, and observe up-regulation of IL-6 and TGFß signalling-induced gene expression in aged bone marrow stroma. Inhibition of TGFß signalling leads to reversal of age-associated HSC platelet lineage bias, increased generation of lymphoid progenitors and rebalanced HSC lineage output in transplantation assays. In contrast, decreased erythropoiesis is not an intrinsic property of aged HSCs, but associated with decreased levels and functionality of erythroid progenitor populations, defects ameliorated by TGFß-receptor and IL-6 inhibition, respectively. These results show that both HSC-intrinsic and -extrinsic mechanisms are involved in age-associated hematopoietic decline, and identify therapeutic targets that promote their reversal.


Assuntos
Envelhecimento/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Interleucina-6/metabolismo , Células-Tronco Mesenquimais/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Envelhecimento/genética , Animais , Medula Óssea , Ciclo Celular/fisiologia , Células Cultivadas , Modelos Animais de Doenças , Células Precursoras Eritroides , Eritropoese/genética , Eritropoese/fisiologia , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Hematopoese , Interleucina-6/genética , Linfopoese/genética , Linfopoese/fisiologia , Proteínas de Membrana , Camundongos , Camundongos Endogâmicos C57BL , Células Mieloides , Transdução de Sinais , Nicho de Células-Tronco , Fator de Crescimento Transformador beta1/genética
5.
Life Sci ; 259: 118239, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32784058

RESUMO

AIMS: MicroRNAs (miRs) are key modulators of cellular processes such as proliferation, apoptosis, as well as anti-cancer immune responses. Here, we evaluated the role of miR-424-5p in breast cancer (BC) and investigated its effects on T cell-related immune response. MAIN METHODS: BC tissues and cell lines were prepared and the expression of miR-424-5p and PD-L1, as well as the underlying molecular pathways, were assessed via qRT-PCR and western blotting. The MTT assay and flow cytometry were used to assess the effect of miR-424-5p on proliferation, apoptosis, autophagy, and cell cycle progression. The co-culture of T cells with MDA-MB-231 was performed for evaluating the role of miR-424-5p in rescuing T cell exhaustion. KEY FINDINGS: The results indicated the down-regulation of miR-424-5p and up-regulation of PD-L1 expression in BC tissue specimens. MiR-424-5p transfection into PD-L1 overexpressing MDA-MB-231 cells decreased the expression of PD-L1. Also, miR-424-5p could reduce MDA-MB-231 cell viability through modulating apoptosis and autophagy pathways. Furthermore, miR-424-5p transfection leads to decreased colony formation and increased cell number at the G2/M phase. Western blot analysis illustrated that miR-424-5p could exert its anti-proliferative effect via modulating PTEN/PI3K/AKT/mTOR pathway. Moreover, it was demonstrated that suppression of PD-L1 by miR-424-5p could participate in regulating the expression of effector cytokines in T cells. SIGNIFICANCE: MiR-424-5p could be considered as a potential tumor-suppressor miR in regulating BC cellular growth, apoptosis, and T cell-related immune response through targeting PD-L1, and its downstream mediators. Therefore, we recognized miR-424-5p as a promising candidate for miR restoration therapy in BC patients.


Assuntos
Antígeno B7-H1/metabolismo , Neoplasias da Mama/metabolismo , MicroRNAs/metabolismo , PTEN Fosfo-Hidrolase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Adulto , Idoso , Apoptose/fisiologia , Autofagia/fisiologia , Antígeno B7-H1/genética , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Ciclo Celular/fisiologia , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Feminino , Genes Supressores de Tumor , Humanos , MicroRNAs/genética , Pessoa de Meia-Idade , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais
6.
Nat Cell Biol ; 22(9): 1076-1090, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32807902

RESUMO

Autophagy is a catabolic process whereby cytoplasmic components are degraded within lysosomes, allowing cells to maintain energy homeostasis during nutrient depletion. Several studies reported that the CDK inhibitor p27Kip1 promotes starvation-induced autophagy by an unknown mechanism. Here we find that p27 controls autophagy via an mTORC1-dependent mechanism in amino acid-deprived cells. During prolonged starvation, a fraction of p27 is recruited to lysosomes, where it interacts with LAMTOR1, a component of the Ragulator complex required for mTORC1 activation. Binding of p27 to LAMTOR1 prevents Ragulator assembly and mTORC1 activation, promoting autophagy. Conversely, p27-/- cells exhibit elevated mTORC1 signalling as well as impaired lysosomal activity and autophagy. This is associated with cytoplasmic sequestration of TFEB, preventing induction of the lysosomal genes required for lysosome function. LAMTOR1 silencing or mTOR inhibition restores autophagy and induces apoptosis in p27-/- cells. Together, these results reveal a direct coordinated regulation between the cell cycle and cell growth machineries.


Assuntos
Aminoácidos/metabolismo , Autofagia/fisiologia , Ciclo Celular/fisiologia , Proliferação de Células/fisiologia , Lisossomos/metabolismo , Antígeno Nuclear de Célula em Proliferação/metabolismo , Transdução de Sinais/fisiologia , Serina-Treonina Quinases TOR/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Células HEK293 , Células HeLa , Humanos , Inanição/metabolismo
7.
Oncol Rep ; 44(4): 1727-1735, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32700752

RESUMO

Hepatocellular carcinoma (HCC) is a common hypervascular tumor disease. Endothelial cells, as a crucial component of the tumor microenvironment, have been reported to participate in angiogenesis and influence the development of tumors, including HCC. Recent studies have demonstrated that circulating RNAs (circRNAs) participate in the functional regulation of endothelial cells. However, the expression and function of circRNAs in endothelial cells under the HCC microenvironment is still unclear. In the present study, we analyzed the expression profiles and investigated the role of circRNAs in human umbilical vein endothelial cells (HUVECs) co­cultured with human primary hepatoma cells. Based on an RNA­sequencing assay, we screened 19 significantly downregulated circRNAs in HUVECs under an HCC microenvironment. Subsequently, we validated the expression of the candidate circRNAs using RT­qPCR, and selected two of the most downregulated circRNAs among them, circ_4911 and circ_4302. Next, through circRNA overexpression experiments, we demonstrated that overexpression of circ_4911 and circ_4302 both inhibited the proliferation and migration of HUVECs, and arrested cells at the GO/G1 stage, while promoting adhesion. Overall, in the present study, we identified the roles of circ_4911 and circ_4302 in regulating functions of HUVECs under an HCC microenvironment.


Assuntos
Carcinoma Hepatocelular/genética , Ácidos Nucleicos Livres/genética , Endotélio Vascular/patologia , Neoplasias Hepáticas/genética , Carcinoma Hepatocelular/sangue , Carcinoma Hepatocelular/irrigação sanguínea , Carcinoma Hepatocelular/patologia , Ciclo Celular/fisiologia , Proliferação de Células/fisiologia , Ácidos Nucleicos Livres/sangue , Técnicas de Cocultura , Endotélio Vascular/metabolismo , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Células Endoteliais da Veia Umbilical Humana , Humanos , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas/irrigação sanguínea , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Análise de Sequência de RNA , Células Tumorais Cultivadas , Microambiente Tumoral
8.
Nat Commun ; 11(1): 3521, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32665556

RESUMO

Microtubules (MTs) mediate mitosis, directional signaling, and are therapeutic targets in cancer. Yet in vivo analysis of cancer cell MT behavior within the tumor microenvironment remains challenging. Here we developed an imaging pipeline using plus-end tip tracking and intravital microscopy to quantify MT dynamics in live xenograft tumor models. Among analyzed features, cancer cells in vivo displayed higher coherent orientation of MT dynamics along their cell major axes compared with 2D in vitro cultures, and distinct from 3D collagen gel cultures. This in vivo MT phenotype was reproduced in vitro when cells were co-cultured with IL4-polarized MΦ. MΦ depletion, MT disruption, targeted kinase inhibition, and altered MΦ polarization via IL10R blockade all reduced MT coherence and/or tumor cell elongation. We show that MT coherence is a defining feature for in vivo tumor cell dynamics and migration, modulated by local signaling from pro-tumor macrophages.


Assuntos
Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Animais , Ciclo Celular/genética , Ciclo Celular/fisiologia , Movimento Celular/genética , Movimento Celular/fisiologia , Feminino , Humanos , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos , Proteínas Associadas aos Microtúbulos/genética , Mitose/genética , Mitose/fisiologia , Análise de Componente Principal , Células RAW 264.7
9.
Proc Natl Acad Sci U S A ; 117(29): 17177-17186, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32631996

RESUMO

Hepatocyte nuclear factor 4α (HNF4α) is a master regulator of liver function and a tumor suppressor in hepatocellular carcinoma (HCC). In this study, we explore the reciprocal negative regulation of HNF4α and cyclin D1, a key cell cycle protein in the liver. Transcriptomic analysis of cultured hepatocyte and HCC cells found that cyclin D1 knockdown induced the expression of a large network of HNF4α-regulated genes. Chromatin immunoprecipitation-sequencing (ChIP-seq) demonstrated that cyclin D1 inhibits the binding of HNF4α to thousands of targets in the liver, thereby diminishing the expression of associated genes that regulate diverse metabolic activities. Conversely, acute HNF4α deletion in the liver induces cyclin D1 and hepatocyte cell cycle progression; concurrent cyclin D1 ablation blocked this proliferation, suggesting that HNF4α maintains proliferative quiescence in the liver, at least, in part, via repression of cyclin D1. Acute cyclin D1 deletion in the regenerating liver markedly inhibited hepatocyte proliferation after partial hepatectomy, confirming its pivotal role in cell cycle progression in this in vivo model, and enhanced the expression of HNF4α target proteins. Hepatocyte cyclin D1 gene ablation caused markedly increased postprandial liver glycogen levels (in a HNF4α-dependent fashion), indicating that the cyclin D1-HNF4α axis regulates glucose metabolism in response to feeding. In AML12 hepatocytes, cyclin D1 depletion led to increased glucose uptake, which was negated if HNF4α was depleted simultaneously, and markedly elevated glycogen synthesis. To summarize, mutual repression by cyclin D1 and HNF4α coordinately controls the cell cycle machinery and metabolism in the liver.


Assuntos
Ciclo Celular/fisiologia , Ciclina D1/genética , Ciclina D1/metabolismo , Fator 4 Nuclear de Hepatócito/genética , Fator 4 Nuclear de Hepatócito/metabolismo , Fígado/metabolismo , Animais , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Modelos Animais de Doenças , Feminino , Técnicas de Silenciamento de Genes , Hepatócitos/metabolismo , Hepatócitos/patologia , Regeneração Hepática/genética , Regeneração Hepática/fisiologia , Masculino , Camundongos Endogâmicos BALB C , Camundongos Knockout
10.
J Vis Exp ; (161)2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32716390

RESUMO

The limited reserve of mature, fertilizable oocytes represents a major barrier for the success of assisted reproduction in mammals. Considering that during the reproductive life span only about 1% of the oocytes in an ovary mature and ovulate, several techniques have been developed to increase the exploitation of the ovarian reserve to the growing population of non-ovulatory follicles. Such technologies have allowed interventions of fertility preservation, selection programs in livestock, and conservation of endangered species. However, the vast potential of the ovarian reserve is still largely unexploited. In cows, for instance, some attempts have been made to support in vitro culture of oocytes at specific developmental stages, but efficient and reliable protocols have not yet been developed. Here we describe a culture system that reproduce the physiological conditions of the corresponding follicular stage, defined to develop in vitro growing oocytes collected from bovine early antral follicles to the fully-grown stage, corresponding to the medium antral follicle in vivo. A combination of hormones and a phosphodiesterase 3 inhibitor was used to prevent untimely meiotic resumption and to guide oocyte's differentiation.


Assuntos
Técnicas de Cultura de Células/métodos , Oócitos/fisiologia , Reserva Ovariana/fisiologia , Reprodução/fisiologia , Animais , Bovinos , Ciclo Celular/fisiologia , Diferenciação Celular/fisiologia , Feminino , Oogênese/fisiologia , Folículo Ovariano/fisiologia , Ovário/citologia , Ovário/fisiologia
11.
Medicine (Baltimore) ; 99(24): e20253, 2020 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-32541451

RESUMO

This study is to explore the molecular mechanism of benign bile duct hypertrophic scar formation.Differential proteins between the normal fibroblast (NFB) and scar fibroblast (SCFB) were screened by protein chip assay, and analyzed by pathway-enrichment analysis and function-enrichment analysis. The differential proteins were further tested by ELISA. SiRNA-Act B was transfected to SCFB to down-regulate the expression of Act B. NFB was incubated with rh-Act B. The cell apoptosis and cell cycle were determined by flow cytometry. The expression of Act B, Smad2/3, transforming growth factor-ß1 (TGF-ß1), endothelin-1 (ET-1), thrombospondin-1 (Tsp-1), and Oncostatin M (OSM) were detected by Western blot.A total of 37 differential proteins were identified in SCFBs by microarray (P < .05), including 27 up-regulated proteins and 10 down-regulated proteins (P < .05). Their function were associated with Activin signaling, synthesis and degradation of extracellular matrix, formation and activation of cytokine, inflammatory reaction, immunoreaction, tissue damage reaction, cell cycle, migration, apoptosis, and secretion, etc. ELISA results showed that the expression of Act B, TGF-ß1, ET-1 were higher in SCFBs, while the expression of Tsp-1 and OSM were lower in SCFBs (P < .05). After interfered by siRNA-Act B, the expression of Act B mRNA decreased (P < .05). The percentage of early apoptosis increased (P < .05). The expression of Act B, Smad2/3, TGF-ß1 were decreased and Tsp-1, OSM were increased (P < .05). After treatment with rh-Act B, the percentage of G0/G1 phase of NFBs was decreased and that of S phase was increased without significance (P > .05). The expression of Act B, Smad2/3, TGF-ß1 were increased (P < .05) and Tsp-1, OSM were decreased (P < .01).There are differentially expressed proteins between SCFBs and NFBs. Activin B signal plays an important role in the process of NFB transforming to SCFB, and TGF-ß1, Smad2/3, Tsp-1, and OSM are important participants.


Assuntos
Ativinas/metabolismo , Ductos Biliares/patologia , Fibroblastos/metabolismo , Fibroblastos/patologia , Transdução de Sinais/fisiologia , Adulto , Apoptose/fisiologia , Ciclo Celular/fisiologia , Cicatriz Hipertrófica , Endotelina-1/metabolismo , Matriz Extracelular/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oncostatina M/metabolismo , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Proteína Smad2/metabolismo , Trombospondina 1/metabolismo , Fator de Crescimento Transformador beta1/metabolismo
12.
Mol Cell ; 78(6): 1178-1191.e6, 2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32485148

RESUMO

The RAS-ERK/MAPK (RAS-extracellular signal-regulated kinase/mitogen-activated protein kinase) pathway integrates growth-promoting signals to stimulate cell growth and proliferation, at least in part, through alterations in metabolic gene expression. However, examples of direct and rapid regulation of the metabolic pathways by the RAS-ERK pathway remain elusive. We find that physiological and oncogenic ERK signaling activation leads to acute metabolic flux stimulation through the de novo purine synthesis pathway, thereby increasing building block availability for RNA and DNA synthesis, which is required for cell growth and proliferation. We demonstrate that ERK2, but not ERK1, phosphorylates the purine synthesis enzyme PFAS (phosphoribosylformylglycinamidine synthase) at T619 in cells to stimulate de novo purine synthesis. The expression of nonphosphorylatable PFAS (T619A) decreases purine synthesis, RAS-dependent cancer cell-colony formation, and tumor growth. Thus, ERK2-mediated PFAS phosphorylation facilitates the increase in nucleic acid synthesis required for anabolic cell growth and proliferation.


Assuntos
Carbono-Nitrogênio Ligases com Glutamina como Doadora de N-Amida/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Purinas/biossíntese , Células A549 , Animais , Carbono-Nitrogênio Ligases com Glutamina como Doadora de N-Amida/genética , Ciclo Celular/fisiologia , Linhagem Celular Tumoral , Proliferação de Células/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Células HeLa , Humanos , Sistema de Sinalização das MAP Quinases/fisiologia , Fosforilação , Purinas/metabolismo , Transdução de Sinais/fisiologia , Proteínas ras/metabolismo
13.
Anticancer Res ; 40(6): 3247-3254, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32487619

RESUMO

BACKGROUND/AIM: 5-Fluorouracil (5-FU) is an anticancer drug commonly used to treat gastric cancer; however, continuous 5-FU chemotherapy causes drug resistance. MATERIALS AND METHODS: We established five sublines of 5-FU-resistant AGS gastric cancer cells to investigate changes that may have occurred in the development of 5-FU resistance. Drug resistance to other chemotherapeutic reagents, proliferation, cell-cycle changes, and wound healing ability were assessed for each subline. RESULTS: Retarded cell growth, G0/G1 phase arrest, up-regulation of p57, and down-regulation of cyclin D1 were commonly observed in all five sublines. Resistance to paclitaxel and cisplatin was also observed in most of the sublines. CONCLUSION: Our data support the notion that G0/G1 arrest due to changes in p57 and cyclin D1 expression may confer drug resistance, while EMT seems non-essential to 5-FU resistance in AGS gastric carcinoma cells.


Assuntos
Fluoruracila/farmacologia , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/patologia , Antimetabólitos Antineoplásicos/farmacologia , Ciclo Celular/fisiologia , Resistencia a Medicamentos Antineoplásicos , Humanos
14.
Proc Natl Acad Sci U S A ; 117(26): 15221-15229, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32546524

RESUMO

The balance between proliferation and differentiation of stem cells and progenitors determines the size of an adult brain region. While the molecular mechanisms regulating proliferation and differentiation of cortical progenitors have been intensively studied, an analysis of the kinetics of progenitor choice between self-renewal and differentiation in vivo is, due to the technical difficulties, still unknown. Here we established a descriptive mathematical model to estimate the probability of self-renewal or differentiation of cortical progenitor behaviors in vivo, a variable we have termed the expansion coefficient. We have applied the model, one which depends only on experimentally measured parameters, to the developing mouse cortex where the expansive neuroepithelial cells and neurogenic radial glial progenitors are coexisting. Surprisingly, we found that the expansion coefficients of both neuroepithelium cells and radial glial progenitors follow the same developmental trajectory during cortical development, suggesting a common rule governing self-renewal/differentiation behaviors in mouse cortical progenitor differentiation.


Assuntos
Diferenciação Celular/fisiologia , Córtex Cerebral/citologia , Modelos Biológicos , Células-Tronco Neurais/fisiologia , Animais , Ciclo Celular/fisiologia , Feminino , Camundongos , Camundongos Endogâmicos ICR
15.
Nat Commun ; 11(1): 2919, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32522980

RESUMO

Replication and transcription of genomic DNA requires partial disassembly of nucleosomes to allow progression of polymerases. This presents both an opportunity to remodel the underlying chromatin and a danger of losing epigenetic information. Centromeric transcription is required for stable incorporation of the centromere-specific histone dCENP-A in M/G1 phase, which depends on the eviction of previously deposited H3/H3.3-placeholder nucleosomes. Here we demonstrate that the histone chaperone and transcription elongation factor Spt6 spatially and temporarily coincides with centromeric transcription and prevents the loss of old CENP-A nucleosomes in both Drosophila and human cells. Spt6 binds directly to dCENP-A and dCENP-A mutants carrying phosphomimetic residues alleviate this association. Retention of phosphomimetic dCENP-A mutants is reduced relative to wildtype, while non-phosphorylatable dCENP-A retention is increased and accumulates at the centromere. We conclude that Spt6 acts as a conserved CENP-A maintenance factor that ensures long-term stability of epigenetic centromere identity during transcription-mediated chromatin remodeling.


Assuntos
Proteína Centromérica A/metabolismo , Proteínas de Drosophila/metabolismo , Fatores de Alongamento de Peptídeos/metabolismo , Fatores de Transcrição/metabolismo , Animais , Western Blotting , Ciclo Celular/genética , Ciclo Celular/fisiologia , Linhagem Celular , Proteína Centromérica A/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Drosophila , Proteínas de Drosophila/genética , Citometria de Fluxo , Imunofluorescência , Células HeLa , Humanos , Imunoprecipitação , Mitose/genética , Mitose/fisiologia , Fatores de Alongamento de Peptídeos/genética , Fatores de Transcrição/genética
16.
Cell Mol Life Sci ; 77(22): 4553-4571, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32476056

RESUMO

A persistent dogma in neuroscience supported the idea that terminally differentiated neurons permanently withdraw from the cell cycle. However, since the late 1990s, several studies have shown that cell cycle proteins are expressed in post-mitotic neurons under physiological conditions, indicating that the cell cycle machinery is not restricted to proliferating cells. Moreover, many studies have highlighted a clear link between cell cycle-related proteins and neurological disorders, particularly relating to apoptosis-induced neuronal death. Indeed, cell cycle-related proteins can be upregulated or overactivated in post-mitotic neurons in case of acute or degenerative central nervous system disease. Given the considerable lack of effective treatments for age-related neurological disorders, new therapeutic approaches targeting the cell cycle machinery might thus be considered. This review aims at summarizing current knowledge about the role of the cell cycle machinery in post-mitotic neurons in healthy and pathological conditions.


Assuntos
Ciclo Celular/fisiologia , Mitose/fisiologia , Neurônios/fisiologia , Animais , Apoptose/fisiologia , Proteínas de Ciclo Celular/metabolismo , Humanos , Doenças do Sistema Nervoso/metabolismo , Doenças do Sistema Nervoso/fisiopatologia , Neurônios/metabolismo
17.
Nat Rev Cancer ; 20(7): 398-411, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32488200

RESUMO

The success of targeted therapies and immunotherapies has created optimism that cancers may be curable. However, not all patients respond, drug resistance is common and many patients relapse owing to dormant cancer cells. These rare and elusive cells can disseminate early and hide in specialized niches in distant organs before being reactivated to cause disease relapse after successful treatment of the primary tumour. Despite their importance, we are yet to leverage knowledge generated from experimental models and translate the potential of targeting dormant cancer cells to prevent disease relapse in the clinic. This is due, at least in part, to the lack of adherence to consensus definitions by researchers, limited models that faithfully recapitulate this stage of metastatic spread and an absence of interdisciplinary approaches. However, the application of new high-resolution, single-cell technologies is starting to revolutionize the field and transcend classical reductionist models of studying individual cell types or genes in isolation to provide a global view of the complex underlying cellular ecosystem and transcriptional landscape that controls dormancy. In this Perspective, we synthesize some of these recent advances to describe the hallmarks of cancer cell dormancy and how the dormant cancer cell life cycle offers opportunities to target not only the cancer but also its environment to achieve a durable cure for seemingly incurable cancers.


Assuntos
Ciclo Celular/fisiologia , Transformação Celular Neoplásica/metabolismo , Metástase Neoplásica/fisiopatologia , Microambiente Tumoral/fisiologia , Comunicação Celular/efeitos dos fármacos , Comunicação Celular/fisiologia , Ciclo Celular/efeitos dos fármacos , Transformação Celular Neoplásica/efeitos dos fármacos , Microambiente Celular/efeitos dos fármacos , Microambiente Celular/fisiologia , Resistencia a Medicamentos Antineoplásicos/fisiologia , Humanos , Terapia de Alvo Molecular/métodos , Metástase Neoplásica/terapia , Neoplasias/tratamento farmacológico , Neoplasias/fisiopatologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/fisiologia , Microambiente Tumoral/efeitos dos fármacos
18.
Arch Biochem Biophys ; 688: 108406, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32417187

RESUMO

Increasing evidence indicates that aberrantly expressed microRNAs play a role in tumorigenesis and progression of gastric cancer. Recently, a novel cancer-related microRNA, miR-621, was found to be involved in cancer pathogenesis. However, the precise molecular mechanisms underlying the oncogenic activity of miR-621 remain unclear and require further investigation. In the current study, we demonstrate that miR-621 expression is downregulated in gastric cancer tissues and cell lines, and its reduction is associated with malignant clinical features including tumor size, lymph node metastasis, tumor-node-metastasis stage and poor prognosis. Functional studies involving gain- and loss-of-function experiments revealed that miR-621 represses cell viability, colony formation, cell cycle progression and proliferation in vitro, and miR-621 overexpression inhibited tumor growth in a gastric cancer xenograft model. SYF2 was identified as a direct target gene of miR-621 in gastric cancer. MiR-621 directly interacts with the SYF2 3'-UTR and post-transcriptionally repressed SYF2 expression in gastric cancer cells. SYF2 was significantly overexpressed in gastric cancer tissues and negatively correlated with miR-621 expression. Moreover, inhibition of SYF2 expression reversed the effects of miR-621 loss in gastric cancer cells. SYF2 overexpression was similar to that induced by miR-621 loss in gastric cancer. Taken together, these studies suggest that miR-621 may be a viable therapeutic target in gastric cancer.


Assuntos
Proliferação de Células/fisiologia , MicroRNAs/metabolismo , Proteínas de Ligação a RNA/metabolismo , Neoplasias Gástricas/fisiopatologia , Animais , Ciclo Celular/fisiologia , Linhagem Celular Tumoral , Ciclina D1/metabolismo , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , Masculino , Camundongos Endogâmicos BALB C , Prognóstico , Neoplasias Gástricas/diagnóstico , Regulação para Cima
19.
Artigo em Inglês | MEDLINE | ID: mdl-32412792

RESUMO

Relative resistance to apoptosis and the ability to proliferate and produce a collagen-rich scar determine the critical role of cardiac fibroblasts in wound healing and tissue remodeling following myocardial injury. Identification of cardiac fibroblast-specific factors and mechanisms underlying these aspects of cardiac fibroblast function is therefore of considerable scientific and clinical interest. In the present study, gene knockdown and overexpression approaches and promoter binding assays showed that discoidin domain receptor 2 (DDR2), a mesenchymal cell-specific collagen receptor tyrosine kinase localized predominantly in fibroblasts in the heart, acts via ERK1/2 MAPK-activated serum response factor (SRF) transcription factor to enhance the expression of antiapoptotic cIAP2 in cardiac fibroblasts, conferring resistance against oxidative injury. Furthermore, DDR2 was found to act via ERK1/2 MAPK-activated SRF to transcriptionally upregulate Skp2 that in turn facilitated post-translational degradation of p27, the cyclin-dependent kinase inhibitor that causes cell cycle arrest, to promote G1-S transition, as evidenced by Rb phosphorylation, increased proliferating cell nuclear antigen (PCNA) levels, and flow cytometry. DDR2-dependent ERK1/2 MAPK activation also suppressed forkhead box O 3a (FoxO3a)-mediated transcriptional induction of p27. Inhibition of the binding of collagen type I to DDR2 using WRG-28 indicated the obligate role of collagen type I in the activation of DDR2 and its regulatory role in cell survival and cell cycle protein expression. Notably, DDR2 levels positively correlated with SRF, cIAP2, and PCNA levels in cardiac fibroblasts from spontaneously hypertensive rats. To conclude, DDR2-mediated ERK1/2 MAPK activation facilitates coordinated regulation of cell survival and cell cycle progression in cardiac fibroblasts via SRF.NEW & NOTEWORTHY Relative resistance to apoptosis and the ability to proliferate and produce a collagen-rich scar enable cardiac fibroblasts to play a central role in myocardial response to injury. This study reports novel findings that mitogen-stimulated cardiac fibroblasts exploit a common regulatory mechanism involving collagen receptor (DDR2)-dependent activation of ERK1/2 MAPK and serum response factor to achieve coordinated regulation of apoptosis resistance and cell cycle progression, which could facilitate their survival and function in the injured myocardium.


Assuntos
Ciclo Celular/fisiologia , Sobrevivência Celular/fisiologia , Receptor com Domínio Discoidina 2/metabolismo , Fibroblastos/metabolismo , Miocárdio/metabolismo , Fatores de Transcrição/metabolismo , Animais , Apoptose/fisiologia , Proliferação de Células/fisiologia , Regulação da Expressão Gênica , Masculino , Ratos , Ratos Endogâmicos SHR , Ratos Sprague-Dawley
20.
Invest Ophthalmol Vis Sci ; 61(5): 31, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32428232

RESUMO

Purpose: More recently, literature has emerged providing findings about the novelty of microRNAs (miR)-targeted therapeutics in the treatment of retinoblastoma (RB). The prime objective of this study was to identify the potential role of miR-378a-3p and its regulation in RB cells via forkhead box G1 (FOXG1). Methods: The expression of miR-378a-3p and FOXG1 in the clinical RB tissues was determined using RNA quantitation and Western blot assays. The interaction between miR-378a-3p and FOXG1 was identified using dual luciferase reporter gene assay. The potential effects of miR-378a-3p on the RB cell biological processes were evaluated by conducting gain- and loss-of-function studies of miR-378a-3p and FOXG1, followed by cell viability, cell cycle progression, and apoptosis measurements. Furthermore, experiments were performed in nude mice to assess its effects on tumor formation. Results: miR-378a-3p was poorly expressed, whereas FOXG1 was highly expressed in RB tissues and cells. miR-378a-3p bound to the FOXG1 3' untranslated region and negatively modulated its expression. The overexpression of miR-378a-3p was found to decrease RB cell viability and to promote cell apoptosis in vitro, whereas overexpressed FOXG1 reversed the regulatory effects of miR-378a-3p on RB cellular behaviors. In nude mice, the restoration of miR-378a-3p by miR-378a-3p agomir was shown to play a role in the reduction of tumor volume and size relative to nude mice injected with negative control-agomir. Conclusions: Our findings identified that increased miR-378a-3p exerted an inhibitory effect on RB cell proliferation by targeting FOXG1, suggesting the role of miR-378a-3p as a novel therapeutic target for RB.


Assuntos
Apoptose , Fatores de Transcrição Forkhead/genética , Regulação Neoplásica da Expressão Gênica/fisiologia , MicroRNAs/fisiologia , Proteínas do Tecido Nervoso/genética , Neoplasias da Retina/patologia , Retinoblastoma/patologia , Animais , Western Blotting , Ciclo Celular/fisiologia , Proliferação de Células/fisiologia , Sobrevivência Celular/fisiologia , Pré-Escolar , Feminino , Citometria de Fluxo , Fatores de Transcrição Forkhead/metabolismo , Perfilação da Expressão Gênica , Humanos , Marcação In Situ das Extremidades Cortadas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteínas do Tecido Nervoso/metabolismo , Plasmídeos/genética , Reação em Cadeia da Polimerase em Tempo Real , Neoplasias da Retina/metabolismo , Retinoblastoma/metabolismo , Organismos Livres de Patógenos Específicos , Transfecção , Transplante Heterólogo , Células Tumorais Cultivadas
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