RESUMO
Macroautophagy/autophagy has been shown to exert a dual role in cancer i.e., promoting cell survival or cell death depending on the cellular context and the cancer stage. Therefore, development of potent autophagy modulators, with a clear mechanistic understanding of their target action, has paramount importance in both mechanistic and clinical studies. In the process of exploring the mechanism of action of a previously identified cytotoxic small molecule (SM15) designed to target microtubules and the interaction domain of microtubules and the kinetochore component NDC80/HEC1, we discovered that the molecule acts as a potent autophagy inhibitor. By using several biochemical and cell biology assays we demonstrated that SM15 blocks basal autophagic flux by inhibiting the fusion of correctly formed autophagosomes with lysosomes. SM15-induced autophagic flux blockage promoted apoptosis-mediated cell death associated with ROS production. Interestingly, autophagic flux blockage, apoptosis induction and ROS production were rescued by genetic or pharmacological inhibition of OGT (O-linked N-acetylglucosamine (GlcNAc) transferase) or by expressing an O-GlcNAcylation-defective mutant of the SNARE fusion complex component SNAP29, pointing to SNAP29 as the molecular target of SM15 in autophagy. Accordingly, SM15 was found to enhance SNAP29 O-GlcNAcylation and, thereby, inhibit the formation of the SNARE fusion complex. In conclusion, these findings identify a new pathway in autophagy connecting O-GlcNAcylated SNAP29 to autophagic flux blockage and autophagosome accumulation, that, in turn, drives ROS production and apoptotic cell death. Consequently, modulation of SNAP29 activity may represent a new opportunity for therapeutic intervention in cancer and other autophagy-associated diseases.
Assuntos
Autofagossomos , Autofagia , Autofagossomos/metabolismo , Autofagia/fisiologia , Macroautofagia , Espécies Reativas de Oxigênio/metabolismo , Lisossomos/metabolismo , Proteínas SNARE/metabolismo , ApoptoseRESUMO
BACKGROUND: Glioblastoma multiforme (GBM) is characterized by several genetic abnormalities, leading to cell cycle deregulation and abnormal mitosis caused by a defective checkpoint. We previously demonstrated that arecaidine propargyl ester (APE), an orthosteric agonist of M2 muscarinic acetylcholine receptors (mAChRs), arrests the cell cycle of glioblastoma (GB) cells, reducing their survival. The aim of this work was to better characterize the molecular mechanisms responsible for this cell cycle arrest. METHODS: The arrest of cell proliferation was evaluated by flow cytometry analysis. Using immunocytochemistry and time-lapse analysis, the percentage of abnormal mitosis and aberrant mitotic spindles were assessed in both cell lines. Western blot analysis was used to evaluate the modulation of Sirtuin2 and acetylated tubulin-factors involved in the control of cell cycle progression. RESULTS: APE treatment caused arrest in the M phase, as indicated by the increase in p-HH3 (ser10)-positive cells. By immunocytochemistry, we found a significant increase in abnormal mitoses and multipolar mitotic spindle formation after APE treatment. Time-lapse analysis confirmed that the APE-treated GB cells were unable to correctly complete the mitosis. The modulated expression of SIRT2 and acetylated tubulin in APE-treated cells provides new insights into the mechanisms of altered mitotic progression in both GB cell lines. CONCLUSIONS: Our data show that the M2 agonist increases aberrant mitosis in GB cell lines. These results strengthen the idea of considering M2 acetylcholine receptors a novel promising therapeutic target for the glioblastoma treatment.
Assuntos
Glioblastoma/metabolismo , Glioblastoma/patologia , Mitose , Receptor Muscarínico M2/metabolismo , Fuso Acromático/metabolismo , Acetilação/efeitos dos fármacos , Arecolina/análogos & derivados , Arecolina/farmacologia , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Humanos , Metáfase/efeitos dos fármacos , Sirtuína 2/metabolismo , Imagem com Lapso de Tempo , Tubulina (Proteína)/metabolismoRESUMO
Nervous system development involves proliferation and cell specification of progenitor cells into neurons and glial cells. Unveiling how this complex process is orchestrated under physiological conditions and deciphering the molecular and cellular changes leading to neurological diseases is mandatory. To date, great efforts have been aimed at identifying gene mutations associated with many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Mutations in the RNA/DNA binding protein Fused in Sarcoma/Translocated in Liposarcoma (FUS/TLS) have been associated with motor neuron degeneration in rodents and humans. Furthermore, increased levels of the wild-type protein can promote neuronal cell death. Despite the well-established causal link between FUS mutations and ALS, its role in neural cells remains elusive. In order to shed new light on FUS functions we studied its role in the control of neural stem progenitor cell (NSPC) properties. Here, we report that human wild-type Fused in Sarcoma (WT FUS), exogenously expressed in mouse embryonic spinal cord-derived NSPCs, was localized in the nucleus, caused cell cycle arrest in G1 phase by affecting cell cycle regulator expression, and strongly reduced neuronal differentiation. Furthermore, the expression of the human mutant form of FUS (P525L-FUS), associated with early-onset ALS, drives the cells preferentially towards a glial lineage, strongly reducing the number of developing neurons. These results provide insight into the involvement of FUS in NSPC proliferation and differentiation into neurons and glia.
Assuntos
Mutação , Células-Tronco Neurais/citologia , Neuroglia/citologia , Neurônios/patologia , Proteína FUS de Ligação a RNA/metabolismo , Medula Espinal/citologia , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Animais , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Células Cultivadas , Camundongos , Células-Tronco Neurais/metabolismo , Células-Tronco Neurais/patologia , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Neuroglia/metabolismo , Neuroglia/patologia , Neurônios/metabolismo , Proteína FUS de Ligação a RNA/genética , Medula Espinal/embriologia , Medula Espinal/metabolismo , Medula Espinal/patologiaRESUMO
Adipose-derived stem cells (ASCs) are an attractive source for regenerative medicine as they can be easily isolated, rapidly expandable in culture and show excellent in vitro differentiation potential. Acetylcholine (ACh), one of the main neurotransmitters in central and peripheral nervous systems, plays key roles in the control of several physiological processes also in non-neural tissues. As demonstrated in our previous studies, ACh can contribute to the rat ASCs physiology, negatively modulating ASCs proliferation and migration via M2 muscarinic receptor (mAChR) activation. In the present work we show that rat ASCs also express α7 nicotinic receptors (nAChRs). In particular, we have investigated the effects mediated by the selective activation of α7 nAChRs, which causes a reduction of ASC proliferation without affecting cell survival and morphology, and significantly promotes cell migration via upregulation of the CXCR4 expression. Interestingly, the activation of the α7 nAChR also upregulates the expression of M2 mAChR protein, indicating a cooperation between muscarinic and nicotinic receptors in the inhibition of ASC proliferation.
Assuntos
Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Células-Tronco Mesenquimais/metabolismo , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Tecido Adiposo/citologia , Animais , Bungarotoxinas/farmacologia , Fumaratos/farmacologia , Masculino , Ratos Sprague-Dawley , Compostos de Espiro/farmacologia , Receptor Nicotínico de Acetilcolina alfa7/agonistas , Receptor Nicotínico de Acetilcolina alfa7/antagonistas & inibidoresRESUMO
One of the major limits of chemotherapy is depending on the ability of the cancer cells to elude and adapt to different drugs. Recently, we demonstrated how the activation of the M2 muscarinic receptor could impair neuroblastoma cell proliferation. In the present paper, we investigate the possible effects mediated by the preferential M2 receptor agonist arecaidine propargyl ester (APE) on drug resistance in two neuroblastoma cell lines, SK-N-BE and SK-N-BE(2C), a sub-clone presenting drug resistance. In both cell lines, we compare the expression of the M2 receptor and the effects mediated by the M2 agonist APE on cell cycle, demonstrating a decreased percentage of cells in S phase and an accumulation of SK-N-BE cells in G1 phase, while the APE treatment of SK-N-BE(2C) cells induced a block in G2/M phase. The withdrawal of the M2 agonist from the medium shows that only the SK-N-BE(2C) cells are able to rescue cell proliferation. Further, we demonstrate that the co-treatment of low doses of APE with doxorubicin or cisplatin significantly counteracts cell proliferation when compared with the single treatment. Analysis of the expression of ATP-binding cassette (ABC) efflux pumps demonstrates the ability of the M2 agonist to downregulate their expression and that this negative modulation may be dependent on N-MYC decreased expression induced by the M2 agonist. Our data demonstrate that the combined effect of low doses of conventional drugs and the M2 agonist may represent a new promising therapeutic approach in neuroblastoma treatment, in light of its significant impact on drug resistance and the possible reduction in the side effects caused by high doses of chemotherapy drugs.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Arecolina/análogos & derivados , Neuroblastoma/tratamento farmacológico , Receptor Muscarínico M2/agonistas , Transportadores de Cassetes de Ligação de ATP/genética , Arecolina/administração & dosagem , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cisplatino/administração & dosagem , Doxorrubicina/administração & dosagem , Resistencia a Medicamentos Antineoplásicos , Expressão Gênica/efeitos dos fármacos , Humanos , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Receptor Muscarínico M2/genéticaRESUMO
Exposure of the developing or adult brain to ionizing radiation (IR) can cause cognitive impairment and/or brain cancer, by targeting neural stem/progenitor cells (NSPCs). IR effects on NSPCs include transient cell cycle arrest, permanent cell cycle exit/differentiation, or cell death, depending on the experimental conditions. In vivo studies suggest that brain age influences NSPC response to IR, but whether this is due to intrinsic NSPC changes or to niche environment modifications remains unclear. Here, we describe the dose-dependent, time-dependent effects of X-ray IR in NSPC cultures derived from the mouse foetal cerebral cortex. We show that, although cortical NSPCs are resistant to low/moderate IR doses, high level IR exposure causes cell death, accumulation of DNA double-strand breaks, activation of p53-related molecular pathways and cell cycle alterations. Irradiated NSPC cultures transiently upregulate differentiation markers, but recover control levels of proliferation, viability and gene expression in the second week post-irradiation. These results are consistent with previously described in vivo effects of IR in the developing mouse cortex, and distinct from those observed in adult NSPC niches or in vitro adult NSPC cultures, suggesting that intrinsic differences in NSPCs of different origins might determine, at least in part, their response to IR.
Assuntos
Córtex Cerebral/citologia , Células-Tronco Neurais/citologia , Células-Tronco Neurais/efeitos da radiação , Animais , Biomarcadores/metabolismo , Ciclo Celular/efeitos da radiação , Morte Celular/efeitos da radiação , Diferenciação Celular/efeitos da radiação , Proliferação de Células/efeitos da radiação , Sobrevivência Celular/efeitos da radiação , Células Cultivadas , Relação Dose-Resposta à Radiação , Histonas/metabolismo , Cinética , Camundongos , Modelos Biológicos , Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima/efeitos da radiação , Raios XRESUMO
Glioblastomas (GBM) are the most aggressive form of primary brain tumors in humans. A key feature of malignant gliomas is their cellular heterogeneity. In particular, the presence of an undifferentiated cell population of defined Glioblastoma Stem cells (GSCs) was reported. Increased expression of anti-apoptotic and chemo-resistance genes in GCSs subpopulation favors their high resistance to a broad spectrum of drugs. Our previous studies showed the ability of M2 muscarinic receptors to negatively modulate the cell growth in GBM cell lines and in the GSCs. The aim of this study was to better characterize the inhibitory effects of M2 receptors on cell proliferation and survival in GSCs and investigate the molecular mechanisms underlying the M2-mediated cell proliferation arrest and decreased survival. Moreover, we also evaluated the ability of M2 receptors to interfere with Notch1 and EGFR pathways, whose activation promotes GSCs proliferation. Our data demonstrate that M2 receptors activation impairs cell cycle progression and survival in the primary GSC lines analyzed (GB7 and GB8). Moreover, we also demonstrated the ability of M2 receptor to inhibit Notch1 and EGFR expression, highlighting a molecular interaction between M2 receptor and the Notch-1/EGFR pathways also in GSCs.
Assuntos
Ciclo Celular/fisiologia , Proliferação de Células/fisiologia , Glioblastoma/patologia , Receptor Muscarínico M2/metabolismo , Receptor Notch1/metabolismo , Transdução de Sinais , Neoplasias Encefálicas/genética , Divisão Celular/fisiologia , Linhagem Celular Tumoral , Receptores ErbB/metabolismo , Glioblastoma/genética , Glioblastoma/metabolismo , Humanos , Células-Tronco Neoplásicas/patologia , Receptor Muscarínico M2/genética , Transdução de Sinais/efeitos dos fármacosRESUMO
Glioblastoma multiforme (GBM) is the most malignant brain tumor. Hypoxic condition is a predominant feature of the GBM contributing to tumor growth and resistance to conventional therapies. Hence, the identification of drugs able to impair GBM malignancy and aggressiveness is considered of great clinical relevance. Previously, we demonstrated that the activation of M2 muscarinic receptors, through the agonist arecaidine propargyl ester (Ape), arrests cell proliferation in GBM cancer stem cells (GSCs). In the present work, we have characterized the response of GSCs to hypoxic condition showing an upregulation of hypoxia-inducible factors and factors involved in the regulation of GSCs survival and proliferation. Ape treatment in hypoxic conditions is however able to inhibit cell cycle progression, causing a significant increase of aberrant mitosis with consequent decreased cell survival. Additionally, qRT-PCR analysis suggest that Ape downregulates the expression of stemness markers and miR-210 levels, one of the main regulators of the responses to hypoxic condition in different tumor types. Our data demonstrate that Ape impairs the GSCs proliferation and survival also in hypoxic condition, negatively modulating the adaptive response of GSCs to hypoxia.
Assuntos
Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Células-Tronco Neoplásicas/metabolismo , Oxigênio/metabolismo , Receptor Muscarínico M2/metabolismo , Neoplasias Encefálicas/genética , Hipóxia Celular , Glioblastoma/genética , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Receptor Muscarínico M2/genética , Células Tumorais CultivadasRESUMO
BACKGROUND: Resveratrol and its natural stilbene-containing derivatives have been extensively investigated as potential chemotherapeutic agents. The synthetic manipulation of the stilbene scaffold has led to the generation of new analogues with improved anticancer activity and better bioavailability. In the present study we investigated the anticancer activity of a novel trimethoxystilbene derivative (3,4,4'-trimethoxylstilbene), where two methoxyl groups are adjacent on the benzene ring (ortho configuration), and compared its activity to 3,5,4'-trimethoxylstilbene, whose methoxyl groups are in meta configuration. RESULTS: We provide evidence that the presence of the two methoxyl groups in ortho configuration renders 3,4,4'-trimethoxystilbene more efficient than the meta isomer in inhibiting cell proliferation and producing apoptotic death in colorectal cancer cells. Confocal microscopy of α- and γ-tubulin staining shows that the novel compound strongly depolymerizes the mitotic spindle and produces fragmentation of the pericentrosomal material. Computer assisted docking studies indicate that both molecules potentially interact with γ-tubulin, and that 3,4,4'-trimethoxystilbene is likely to establish stronger interactions with the protein. CONCLUSIONS: These findings demonstrate the ortho configuration confers higher specificity for γ-tubulin with respect to α-tubulin on 3,4,4' trimethoxystilbene, allowing it to be defined as a new γ-tubulin inhibitor. A strong interaction with γ-tubulin might be a defining feature of molecules with high anticancer activity, as shown for the 3,4,4' isomer.
RESUMO
In previous studies, we found that the orthosteric muscarinic agonist arecaidine propargyl ester (APE) (100⯵M) induced a decreased cell proliferation and severe apoptosis in glioblastoma cancer stem cells (GSCs). In this report, we have investigated the effects mediated by hybrid (orthosteric/allosteric) muscarinic agonists P-6-Iper and N-8-Iper on GSCs survival. At variance with APE, the agonist N-8-Iper inhibited cell growth in a dose dependent manner and also impaired cell survival at low doses. The inhibitory effects of the N-8-Iper action appear to be mediated by M2 receptor activation, since they were strongly reduced by co-administration of the selective M2 receptor antagonist methoctramine as well as upon M2 receptor silencing. Moreover, analysis of the expression of phosphorylated histone H2AX (γ-H2AX) indicated that the treatment with N-8-Iper produced a decreased cell survival by induction of DNA damage. The ability of N-8-Iper to produce a cytotoxic effect and apoptosis at low doses indicates that this muscarinic agonist is a suitable probe in a putative therapeutic intervention on glioblastoma through M2 receptor activation.
Assuntos
Glioblastoma/patologia , Agonistas Muscarínicos/farmacologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Receptor Muscarínico M2/agonistas , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/fisiologia , Relação Dose-Resposta a Droga , Humanos , Receptor Muscarínico M2/metabolismoRESUMO
Mesenchymal stem cells (MSCs), also known as stromal mesenchymal stem cells, are multipotent cells, which can be found in many tissues and organs as bone marrow, adipose tissue and other tissues. In particular MSCs derived from Adipose tissue (ADSCs) are the most frequently used in regenerative medicine because they are easy to source, rapidly expandable in culture and excellent differentiation potential into adipocytes, chondrocytes, and other cell types. Acetylcholine (ACh), the most important neurotransmitter in Central nervous system (CNS) and peripheral nervous system (PNS), plays important roles also in non-neural tissue, but its functions in MSCs are still not investigated. Although MSCs express muscarinic receptor subtypes, their role is completely unknown. In the present work muscarinic cholinergic effects were characterized in rat ADSCs. Analysis by RT-PCR demonstrates that ADSCs express M1-M4 muscarinic receptor subtypes, whereas M2 is one of the most expressed subtype. For this reason, our attention was focused on M2 subtype. By using the selective M2 against Arecaidine Propargyl Ester (APE) we performed cell proliferation and migration assays demonstrating that APE causes cell growth and migration inhibition without affecting cell survival. Our results indicate that ACh via M2 receptors, may contribute to the maintaining of the ADSCs quiescent status. These data are the first evidence that ACh, via muscarinic receptors, might contribute to control ADSCs physiology.
Assuntos
Acetilcolina/metabolismo , Tecido Adiposo/citologia , Células-Tronco Mesenquimais/citologia , Receptor Muscarínico M2/genética , Acetilcolina/antagonistas & inibidores , Tecido Adiposo/metabolismo , Animais , Arecolina/análogos & derivados , Arecolina/farmacologia , Diferenciação Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Ratos , Receptor Muscarínico M1/genética , Receptor Muscarínico M2/agonistas , Ativação Transcricional/efeitos dos fármacosRESUMO
Natural compounds are extensively studied for their potential use in traditional and non-traditional medicine. Several natural and synthetic Resveratrol analogues have shown interesting biological activities in the field of cancer chemoprevention. In the present study, we have focused on the ability of Resveratrol and two methoxylated derivatives (Trimethoxystilbene and Pterostilbene) to inhibit human cancer cell growth particularly analyzing their ability to interfere with tubulin dynamics at mitosis. We show that Trimethoxystilbene, differently from Resveratrol and Pterostilbene, alters microtubule polymerization dynamics in HeLa cells specifically inducing multipolar spindles and mitotic arrest coupled to a reduction of cell growth and an increase in apoptotic death by mitotic catastrophe. This work demonstrates that the structural modification of Rsv causes substantial changes in the mechanism of action of the derivatives. The presence of three extra methyl groups renders Trimethoxy very efficient in impairing cell proliferation by inducing mitotic catastrophe in cancer cells. © 2016 Wiley Periodicals, Inc.
Assuntos
Mitose/efeitos dos fármacos , Neoplasias/genética , Estilbenos/farmacologia , Tubulina (Proteína)/metabolismo , Animais , Células CHO , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cricetulus , Células HeLa , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Resveratrol , Estilbenos/química , Tubulina (Proteína)/efeitos dos fármacosRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Xanthium strumarium L. is a member of the Asteraceae family popularly used with multiple therapeutic purposes. Whole extracts of this plant have shown anti-mitotic activity in vitro suggesting that some components could induce mitotic arrest in proliferating cells. AIM OF THE SUDY: Aim of the present work was to characterize the anti-mitotic properties of the X. strumarium whole extract and to isolate and purify active molecule(s). MATERIALS AND METHODS: The capacity of the whole extract to inhibit mitotic progression in mammalian cultured cells was investigated to identify its anti-mitotic activity. Isolation of active component(s) was performed using a bioassay-guided multistep separation procedure in which whole extract was submitted to a progressive process of fractionation and fractions were challenged for their anti-mitotic activity. RESULTS: Our results show for the first time that X. strumarium whole extract inhibits assembly of the mitotic spindle and spindle-pole separation, thereby heavily affecting mitosis, impairing the metaphase to anaphase transition and inducing apoptosis. The purification procedure led to a fraction with an anti-mitotic activity comparable to that of the whole extract. Chemical analysis of this fraction showed that its major component was xanthatin. CONCLUSIONS: The present work shows a new activity of X. strumarium extract, i.e. the alteration of the mitotic apparatus in cultured cells that may be responsible for the anti-proliferative activity of the extract. Anti-mitotic activity is shown to be mainly exerted by xanthatin.
Assuntos
Proliferação de Células/efeitos dos fármacos , Furanos/química , Furanos/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Fuso Acromático/efeitos dos fármacos , Xanthium/química , Animais , Apoptose/efeitos dos fármacos , Células CHO , Linhagem Celular , CricetulusRESUMO
Resveratrol (3,4',5-trihydroxystilbene; RSV) acts on cancer cells in several ways, inducing cell cycle delay and apoptotic death, and enhancing ionizing radiation (IR)-mediated responses. However, fewer studies have examined RSV effects on normal cells. We have treated human lymphocytes in vitro with RSV, either alone or combined with IR, to evaluate its potential use as a radioprotector. We measured the effects of RSV on induction of DNA damage, repair kinetics, and modulation of histone deacetylase activity.
Assuntos
Radiação Ionizante , Estilbenos/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/efeitos da radiação , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/efeitos da radiação , Citometria de Fluxo , Humanos , Linfócitos/efeitos dos fármacos , Linfócitos/efeitos da radiação , ResveratrolRESUMO
Various naturally occurring stilbene-like compounds that are related to resveratrol (RSV) possess some of the beneficial effects of the parent molecule and provide even further benefits. Therefore, a series of methoxylated analogues of RSV were prepared with the aim of increasing antitumour and proapoptotic activity. In a previous article, we studied two methoxy-derivatives, pterostilbene (PTERO) and trimethoxystilbene (TRIMETHOXY), in which the first was formed by the substitution of two hydroxyl groups with two methoxy groups (trans-3,5-dimethoxy-4'-hydroxystilbene) and the second was formed by the replacement of all three OH groups with methoxy groups (trans-3,5,4'-trimethoxystilbene). Both methoxy-derivatives showed stronger antioxidant activity when compared with RSV. In the present article, we focused on the analysis of the ability of RSV and its two methoxylated derivatives to protect proliferating non-tumoural cells from the damage induced by ionising radiation (IR). First we showed that the methoxy derivatives, contrary to their parental compound, are unable to affect topoisomerase enzyme and consequently are not clastogenic per se Second we showed that both PTERO and TRIMETHOXY more efficiently reduce the chromosome damage induced by IR. Furthermore, TRIMETHOXY, but not PTERO, causes a delay in cell proliferation, particularly in mitosis progression increasing the number of cells in metaphase at the expense of prophases and ana/telophases.
Assuntos
Dano ao DNA , Radiação Ionizante , Estilbenos/farmacologia , Animais , Células CHO , Proliferação de Células/efeitos dos fármacos , Cricetulus/genética , Cricetulus/fisiologia , DNA/efeitos da radiação , Mitose/efeitos dos fármacos , Resveratrol , Estilbenos/toxicidade , Inibidores da Topoisomerase/farmacologiaRESUMO
The p38/MAPK-activated kinase 2 (MK2) pathway is involved in a series of pathological conditions (inflammation diseases and metastasis) and in the resistance mechanism to antitumor agents. None of the p38 inhibitors entered advanced clinical trials because of their unwanted systemic side effects. For this reason, MK2 was identified as an alternative target to block the pathway but avoiding the side effects of p38 inhibition. However, ATP-competitive MK2 inhibitors suffered from low solubility, poor cell permeability, and scarce kinase selectivity. Fortunately, non-ATP-competitive inhibitors of MK2 have been already discovered that allowed circumventing the selectivity issue. These compounds showed the additional advantage to be effective at lower concentrations in comparison to the ATP-competitive inhibitors. Therefore, although the significant difficulties encountered during the development of these inhibitors, MK2 is still considered as an attractive target to treat inflammation and related diseases to prevent tumor metastasis and to increase tumor sensitivity to chemotherapeutics.
Assuntos
Ensaios Clínicos como Assunto , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas , Cristalização , Cristalografia por Raios X , Humanos , Inibidores de Proteínas Quinases/química , Relação Estrutura-AtividadeRESUMO
Glioblastomas are the most common brain tumors in humans. Previously, we demonstrated that the muscarinic receptor agonist, arecaidine propargyl ester, via M2 receptors, inhibits cell proliferation in a time and dose-dependent manner and induces a severe apoptosis in human U251 and U87 glioblastoma cell lines. In order to clarify the mechanisms causing apoptosis after arecaidine treatment, we analyzed the ability of arecaidine to induce oxidative stress. By dichloro-dihydro-fluorescein diacetate (DCFDA) staining, we demonstrated that arecaidine increased the intracellular ROS levels. ROS accumulation was completely counteracted by the ROS scavenger, N-acetyl-l-cysteine (NAC). Apoptotic cell death appeared directly correlated to ROS production since NAC was able to counteract this effect. Although there was an up-regulation of some detoxifying enzyme expression such as superoxide dismutase (MnSOD) and sirtuin-1 (SIRT1), the cytotoxic effect caused by arecaidine treatment caused DNA damage, as demonstrated by the increase of histone γ-H2AX positive cells, and chromosomal aberrations. These effects were mediated by M2 receptor activation; in fact after silencing of M2 receptors by siRNA, the increase of γ-H2AX positive cells was abolished. In conclusion, in addition to a cytostatic effect previously described, in the present study we have better characterized the mechanisms causing the cytotoxic effects and the apoptotic cell death in glioblastoma cells after M2 receptor activation. These data allow to consider this receptor a new interesting therapeutic tool for the glioblastoma treatment.
Assuntos
Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Glioblastoma/metabolismo , Agonistas Muscarínicos/farmacologia , Receptor Muscarínico M2/genética , Receptor Muscarínico M2/metabolismo , Acetilcisteína/farmacologia , Neoplasias Encefálicas/metabolismo , Linhagem Celular Tumoral , Humanos , Receptores Muscarínicos/genética , Receptores Muscarínicos/metabolismoRESUMO
In recent years, a great interest has emerged in resveratrol (RSV) activity in the prevention of various pathologies including cancer. We recently showed that RSV is able to interfere with topoisomerase II-α (TOPO2) activity in cancer cells, thus inducing a delay in S-phase progression with concomitant phosphorylation of the histone H2AX. TOPO2 is mainly active in proliferating cells and is involved in the resolution of supercoiled DNA and chromosome segregation during mitosis. Here, we studied the effects of RSV in CHO-K1 cells concerning to chromosome damage and segregation as a consequence of TOPO2 inhibition. We show an increase in micronuclei and in polyploid and endoreduplicated cells due to incorrect chromosome segregation. Furthermore, since incomplete segregation can also affect the normal distribution of mitotic figures, we checked mitosis progression showing an increase in metaphase in relation to ana-telophase after RSV treatment. On the whole, our data show that RSV affects chromosome stability and segregation in proliferating cells, probably interfering with TOPO2 activity.
Assuntos
Antígenos de Neoplasias/metabolismo , Antineoplásicos Fitogênicos/farmacologia , DNA Topoisomerases Tipo II/metabolismo , Proteínas de Ligação a DNA/metabolismo , Inibidores Enzimáticos/farmacologia , Estilbenos/farmacologia , Animais , Células CHO , Deleção Cromossômica , Segregação de Cromossomos/efeitos dos fármacos , Cricetinae , Dano ao DNA/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Humanos , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Mitose/efeitos dos fármacos , Poliploidia , ResveratrolRESUMO
SCOPE: Furan is a potent hepatotoxicant and liver carcinogen in rodents. However, short-term tests for genotoxicity of furan are inconclusive. The aim of this study was to assess the potential of furan to covalently bind to DNA, and to assess furan genotoxicity in rats in vivo. MATERIALS AND METHODS: Accelerator mass spectrometry was used to determine the (14) C-content in DNA following administration of [3,4-(14) C]-furan (0.1 and 2.0 mg/kg bw) to F344 rats. DNA damage, micronuclei, chromosomal aberrations, and sister chromatid exchanges were analyzed in F344 rats treated with furan for up to 28 days. CONCLUSION: The (14) C-content in liver DNA was significantly increased in a dose-dependent manner, with mean concentrations of 7.9 ± 3.5 amol (14) C/µg DNA and 153.3 ± 100.2 amol (14) C/µg DNA, corresponding to 16.5 ± 7.4 and 325.2 ± 212.7 adducts/10(9) nucleotides at 0.1 and 2.0 mg/kg bw, respectively. There was no evidence for genotoxicity of furan in peripheral blood and bone marrow cells. However, a dose-related increase in the incidence of chromosomal aberrations in rat splenocytes and some indication of DNA damage in liver were observed. Collectively, results from this study indicate that furan may operate-at least in part-by a genotoxic mode of action.
Assuntos
Carcinógenos/toxicidade , Aberrações Cromossômicas/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Proteínas de Ligação a DNA/efeitos dos fármacos , Furanos/toxicidade , Animais , Células da Medula Óssea/efeitos dos fármacos , Ensaio Cometa , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Testes para Micronúcleos , Neoplasias/induzido quimicamente , Ratos , Ratos Endogâmicos F344 , Troca de Cromátide Irmã/efeitos dos fármacosRESUMO
In this work we have examined the genotoxic potential of the bioinsecticide Azadirachtin A (AZA) and its influence on cell proliferation on human lymphocytes and Chinese Hamster ovary (CHO) cells. AZA genotoxicity was assessed by the analysis of chromosomal aberrations and sister chromatid exchanges (SCEs) in the absence and presence of rat liver S9 metabolism. Primary DNA damage was also investigated by means of the comet assay. The results obtained clearly indicate that AZA is not genotoxic in mammalian cells. On the other hand, AZA proved to interfere with cell cycle progression as shown by modulation of frequencies of first (M1) and second division (M2) metaphases detected by 5-Bromo-2'-deoxyuridine labeling. Accumulation of M1 metaphases were more pronounced in human lymphocytes. In the transformed CHO cell line, however, significant increases of multinucleated interphases and polyploid cells were observed at long treatment time. At higher dose-levels, the incidence of polyploidy was close to 100%. Identification of spindle structure and number of centrosomes by fluorescent immunostaining with α- and γ-tubulin antibodies revealed aberrant mitoses exhibiting multipolar spindles with several centrosomal signals. These findings suggest that AZA can act either through a stabilizing activity of microtubules or by inhibition of Aurora A, since both mechanisms are able to generate genetically unstable polyploid cells with multipolar spindles and multinucleated interphases.