RESUMO
PURPOSE: Information on the general health of transgender and gender diverse (TGD) individuals continues to be lacking. To bridge this gap, the National Institute of Health in Italy together with the National Office against Racial Discriminations, clinical centres, and TGD organizations carried out a cross-sectional study to define the sociodemographic profile, health-related behaviours, and experiences of healthcare access in Italian TGD adult population. METHODS: A national survey was conducted by Computer-Assisted Web Interviewing (CAWI) technique. Collected data were compared within the TGD subgroups and between TGD people and the Italian general population (IGP). RESULTS: TGD respondents were 959: 65% assigned female at birth (AFAB) and 35% assigned male at birth (AMAB). 91.8% and 8.2% were binary and non-binary TGD respondents, respectively. More than 20% of the TGD population reported to be unemployed with the highest rate detectable in AMAB and non-binary people. Cigarette smoking and binge drinking were higher in the TGD population compared with IGP (p < 0.05), affecting TGD subgroups differently. A significant lower percentage of AFAB TGD people reported having had screening for cervical and breast cancer in comparison with AFAB IGP (p < 0.0001, in both cases). Over 40% was the percentage of AFAB and non-binary TGD people accessing healthcare who felt discriminated against because of their gender identity. CONCLUSIONS: Our results are a first step towards a better understanding of the health needs of TGD people in Italy in order to plan the best policy choices for a more inclusive public health.
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An inverted pH gradient across the cell membranes is a typical feature of malignant cancer cells that are characterized by extracellular acidosis and cytosol alkalization. These dysregulations are able to create a unique milieu that favors tumor progression, metastasis and chemo/immune-resistance traits of solid tumors. A key event mediating tumor cell pH alterations is an aberrant activation of ion channels and proton pumps such as (H+)-vacuolar-ATPase (V-ATPase). TM9SF4 is a poorly characterized transmembrane protein that we have recently shown to be related to cannibal behavior of metastatic melanoma cells. Here, we demonstrate that TM9SF4 represents a novel V-ATPase-associated protein involved in V-ATPase activation. We have observed in HCT116 and SW480 colon cancer cell lines that TM9SF4 interacts with the ATP6V1H subunit of the V-ATPase V1 sector. Suppression of TM9SF4 with small interfering RNAs strongly reduces assembly of V-ATPase V0/V1 sectors, thus reversing tumor pH gradient with a decrease of cytosolic pH, alkalization of intracellular vesicles and a reduction of extracellular acidity. Such effects are associated with a significant inhibition of the invasive behavior of colon cancer cells and with an increased sensitivity to the cytotoxic effects of 5-fluorouracil. Our study shows for the first time the important role of TM9SF4 in the aberrant constitutive activation of the V-ATPase, and the development of a malignant phenotype, supporting the potential use of TM9SF4 as a target for future anticancer therapies.
Assuntos
Neoplasias do Colo/patologia , Resistencia a Medicamentos Antineoplásicos/fisiologia , Proteínas de Membrana/metabolismo , Invasividade Neoplásica/patologia , ATPases Vacuolares Próton-Translocadoras/metabolismo , Western Blotting , Linhagem Celular Tumoral , Neoplasias do Colo/metabolismo , Transferência Ressonante de Energia de Fluorescência , Humanos , Concentração de Íons de Hidrogênio , Imunoprecipitação , Microscopia Confocal , Reação em Cadeia da Polimerase , TransfecçãoRESUMO
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) acts as an apoptosis inducer for cancer cells sparing non-tumor cell targets. However, several phase I/II clinical trials have shown limited benefits of this molecule. In the present work, we investigated whether cell susceptibility to TRAIL ligation could be due to the presence of TRAIL death receptors (DRs) 4 and 5 in membrane microdomains called lipid rafts. We performed a series of analyses, either by biochemical methods or fluorescence resonance energy transfer (FRET) technique, on normal cells (i.e. lymphocytes, fibroblasts, endothelial cells), on a panel of human cancer B-cell lines as well as on CD19(+) lymphocytes from patients with B-chronic lymphocytic leukemia, treated with different TRAIL ligands, that is, recombinant soluble TRAIL, specific agonistic antibodies to DR4 and DR5, or CD34(+) TRAIL-armed cells. Irrespective to the expression levels of DRs, a molecular interaction between ganglioside GM3, abundant in lymphoid cells, and DR4 was detected. This association was negligible in all non-transformed cells and was strictly related to TRAIL susceptibility of cancer cells. Interestingly, lipid raft disruptor methyl-beta-cyclodextrin abrogated this susceptibility, whereas the chemotherapic drug perifosine, which induced the recruitment of TRAIL into lipid microdomains, improved TRAIL-induced apoptosis. Accordingly, in ex vivo samples from patients with B-chronic lymphocytic leukemia, the constitutive embedding of DR4 in lipid microdomains was associated per se with cell death susceptibility, whereas its exclusion was associated with TRAIL resistance. These results provide a key mechanism for TRAIL sensitivity in B-cell malignances: the association, within lipid microdomains, of DR4 but not DR5, with a specific ganglioside, that is the monosialoganglioside GM3. On these bases we suggest that lipid microdomains could exert a catalytic role for DR4-mediated cell death and that an ex vivo quantitative FRET analysis could be predictive of cancer cell sensitivity to TRAIL.
Assuntos
Apoptose/efeitos dos fármacos , Leucemia Linfocítica Crônica de Células B/metabolismo , Leucemia Linfocítica Crônica de Células B/patologia , Microdomínios da Membrana/metabolismo , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Anticorpos/farmacologia , Antígenos CD34/metabolismo , Linhagem Celular Transformada , Linhagem Celular Tumoral , Separação Celular , Citometria de Fluxo , Humanos , Microdomínios da Membrana/efeitos dos fármacos , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/agonistas , SolubilidadeRESUMO
Sex/gender differences in terms of incidence, prevalence, age at onset and severity have been documented for several complex adulthood diseases. However, several pediatric diseases also displayed a gender disparity. Unfortunately, epidemiologic studies investigating gender disparity in pediatric age show dissimilar results often depending on the spatial and temporal issues, to considerable regional environmental variations, to social conditions or to infectious agent virulence. Anyway, studies over time showed that gender disparity in childhood mortality and morbidity may be narrow in some pathological conditions whereas in other severe diseases, e.g. sepsis, some cancers and some immune disorders, the disproportion was found as significant. In this work we briefly review literature data dealing with sex/gender differences in morbidity and mortality observed during the pediatric age. In particular, communicable and non-communicable diseases, including cancer, have been considered. The possible mechanisms underlining these differences, e.g. hormonal and epigenetic, are also discussed. The analysis of literature available as concerns pediatric age seems to underline that gender differences start very early in human beings and that hormones as well as gene expression in XX and XY cells can play a role. A reappraisal of the gender issue in pediatric research could thus be pivotal: it might contribute to the improvement of diagnostic and therapeutic strategies as well as to the improvement of the appropriateness of the cures.
Assuntos
Doença/classificação , Pediatria , Fatores Sexuais , Pré-Escolar , Doenças Transmissíveis , Anormalidades Congênitas , Feminino , Humanos , Lactente , Mortalidade Infantil , Recém-Nascido , MasculinoRESUMO
It has become evident that an autoimmune component could play a role in Alzheimer's disease (AD) onset and/or progression. The aim of this study was to identify neuronal antigenic targets specifically recognized by serum autoantibodies and to investigate their cellular effects and their possible pathogenetic role. We identified, by an immunoproteomic approach using mouse brain proteins, the adenosine triphosphate (ATP) synthase ß subunit as a new autoantigen in AD. Using an ELISA assay we found that serum anti-ATP synthase autoantibodies were present in 38% of patients with AD, but in no age-matched healthy subjects or in patients with Parkinson's disease or atherosclerosis. Analytical cytology studies, using SH-SY5Y neuroblastoma cell line, showed that ATP synthase autoantibodies were capable of inducing the inhibition of ATP synthesis, alterations of mitochondrial homeostasis and cell death by apoptosis. These findings suggest that autoantibodies specific to ATP synthase can exert a pathogenetic role via a mechanism that brings into play the impairment of the extracellular ATP homeostasis and the alteration of mitochondrial function triggering cell death by apoptosis.
Assuntos
Doença de Alzheimer/sangue , Doença de Alzheimer/imunologia , Autoanticorpos/sangue , ATPases Mitocondriais Próton-Translocadoras/imunologia , Trifosfato de Adenosina/metabolismo , Trifosfato de Adenosina/farmacologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/líquido cefalorraquidiano , Animais , Anexina A5/metabolismo , Apoptose/efeitos dos fármacos , Autoanticorpos/farmacologia , Encéfalo/metabolismo , Linhagem Celular Tumoral , Eletroforese em Gel Bidimensional , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Lúpus Eritematoso Sistêmico/sangue , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Pessoa de Meia-Idade , Esclerose Múltipla/sangue , Neuroblastoma/patologia , Alinhamento de Sequência , Fatores de Tempo , Adulto JovemRESUMO
It was shown that receptor-mediated apoptosis involves a cascade of subcellular events including alterations of mitochondria. Loss of mitochondrial membrane potential that follows death receptor ligation allows the release of apoptogenic factors that result in apoptosis execution. Further important mitochondrial changes have been observed in this regard: mitochondrial remodeling and fission that appear as prerequisites for the occurrence of the cell death program. As it was observed that lipid rafts, glycosphingolipid-enriched structures, can participate in the apoptotic cascade being recruited to the mitochondria under receptor-mediated proapoptotic stimulation, we decided to analyze the possible implication of these microdomains in mitochondrial fission. We found that molecules involved in mitochondrial fission processes are associated with these domains. In particular, although hFis1 was constitutively included in mitochondrial raft-like domains, dynamin-like protein 1 was recruited to these domains on CD95/Fas triggering. Accordingly, the disruption of rafts, for example, by inhibiting ceramide synthase, leads to the impairment of fission molecule recruitment to the mitochondria, reduction of mitochondrial fission and a significant reduction of apoptosis. We hypothesize that under apoptotic stimulation the recruitment of fission-associated molecules to the mitochondrial rafts could have a role in the morphogenetic changes leading to organelle fission.
Assuntos
Apoptose , Microdomínios da Membrana/química , Mitocôndrias/ultraestrutura , Membranas Mitocondriais/química , Proteínas Mitocondriais/análise , Células Cultivadas , Centrifugação com Gradiente de Concentração , Dinaminas , Inibidores Enzimáticos/farmacologia , Fumonisinas/farmacologia , GTP Fosfo-Hidrolases/análise , Gangliosídeos/análise , Humanos , Proteínas de Membrana/análise , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/genética , Proteínas Associadas aos Microtúbulos/análise , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/genética , Octoxinol , Oxirredutases/antagonistas & inibidores , Interferência de RNA , Receptor fas/metabolismoRESUMO
The term self-cannibalism, or autophagy, was coined to describe the ability of the cells to cannibalize their own damaged organelles or proteins. It was morphologically described as the presence of double-membraned autophagic vesicles filled with diverse cellular materials or debris inside the cells. Hence, more recently, the presence of autophagic vacuoles has been associated with cell survival, including cell senescence and cancer and appears to be activated by nutrient deprivation. The occurrence of autophagic processes can also lead, as final event, to the death of the cell. In this review we summarize the results reported in literature on a phagic process that appears to be related to self-cannibalism: the xeno-cannibalism. This was described as the ability of certain cells, e.g. metastatic cells, to cannibalize their siblings as well as cells from the immune system. Interestingly, metastatic tumor cells are also able to engulf and digest living cells, including autologous lymphocytes that should kill them, i.e. CD8(+) cytotoxic lymphocytes. This can represent a formidable opportunity for metastatic cells to survive in adverse conditions such as those they encounter in their "journey" towards the target organ to establish a colony. Altogether these findings seem to suggest a pathogenetic role for cannibalic behavior in human pathology and point at this surprising cellular aggressiveness as an innovative pharmacological target in the clinical management of metastatic disease.
Assuntos
Autofagia/fisiologia , Sobrevivência Celular/fisiologia , Neoplasias/metabolismo , Senescência Celular/fisiologia , Sistemas de Liberação de Medicamentos , Humanos , Sistema Imunitário/citologia , Sistema Imunitário/metabolismo , Modelos Biológicos , Metástase Neoplásica/tratamento farmacológico , Metástase Neoplásica/fisiopatologia , Neoplasias/tratamento farmacológico , Vacúolos/metabolismoRESUMO
Subcellular organelles such as mitochondria, endoplasmic reticulum (ER) and the Golgi complex are involved in the progression of the cell death programme. We report here that soon after ligation of Fas (CD95/Apo1) in type II cells, elements of the Golgi complex intermix with mitochondria. This mixing follows centrifugal dispersal of secretory membranes and reflects a global alteration of membrane traffic. Activation of apical caspases is instrumental for promoting the dispersal of secretory organelles, since caspase inhibition blocks the outward movement of Golgi-related endomembranes and reduces their mixing with mitochondria. Caspase inhibition also blocks the FasL-induced secretion of intracellular proteases from lysosomal compartments, outlining a novel aspect of death receptor signalling via apical caspases. Thus, our work unveils that Fas ligand-mediated apoptosis induces scrambling of mitochondrial and secretory organelles via a global alteration of membrane traffic that is modulated by apical caspases.
Assuntos
Complexo de Golgi/metabolismo , Membranas Intracelulares/metabolismo , Mitocôndrias/metabolismo , Receptores de Morte Celular/metabolismo , Receptor fas/metabolismo , Apoptose , Caspases/metabolismo , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Proteína Ligante Fas/metabolismo , Células HeLa , Humanos , Células Jurkat , Ligantes , Lisossomos/enzimologia , Organelas/metabolismo , Peptídeo Hidrolases/metabolismo , Transdução de SinaisRESUMO
CD95(APO-1/Fas)-mediated apoptosis of bystander uninfected T cells exerts a major role in the HIV-1-mediated CD4+ T-cell depletion. HIV-1 gp120 has a key role in the induction of sensitivity of human lymphocytes to CD95-mediated apoptosis through its interaction with the CD4 receptor. Recently, we have shown the importance of CD95/ezrin/actin association in CD95-mediated apoptosis. In this study, we explored the hypothesis that the gp120-mediated CD4 engagement could be involved in the induction of susceptibility of primary human T lymphocytes to CD95-mediated apoptosis through ezrin phosphorylation and ezrin-to-CD95 association. Here, we show that gp120/IL-2 combined stimuli, as well as the direct CD4 triggering, on human primary CD4(+)T lymphocytes induced an early and stable ezrin activation through phosphorylation, consistent with the induction of ezrin/CD95 association and susceptibility to CD95-mediated apoptosis. Our results provide a new mechanism through which HIV-1-gp120 may predispose resting CD4(+)T cell to bystander CD95-mediated apoptosis and support the key role of ezrin/CD95 linkage in regulating susceptibility to CD95-mediated apoptosis.
Assuntos
Apoptose/fisiologia , Proteína gp120 do Envelope de HIV/toxicidade , Fosfoproteínas/metabolismo , Linfócitos T/metabolismo , Receptor fas/metabolismo , Apoptose/efeitos dos fármacos , Antígenos CD4/metabolismo , Proteínas do Citoesqueleto , Humanos , Interleucina-2/metabolismo , Ativação Linfocitária/fisiologia , FosforilaçãoRESUMO
Multidrug resistance caused by P-glycoprotein (P-170) is a phenomenon by which cells exposed to a single drug acquire resistance to other structurally and functionally unrelated drugs. This is a widespread phenomenon described in vivo in the management of infectious as well as non-infectious diseases. Several in vitro models have been developed in order to evaluate physiopathological properties of P-170. Among these are P-170-expressing variants of the human T-lymphoblastoid CEM cell line called VBL100. As a general rule, drug resistance normally results in resistance to apoptosis induction. By contrast, a paradoxical activity is exerted in this cell model by the cytokine tumour necrosis factor-alpha (TNF-alpha), which is capable of inducing apoptosis in P-170-expressing variants better than in wild-type (wt) cells. In the present study we partially address the mechanisms underlying this activity. In fact, the susceptibility of VBL100 cells to TNF-alpha appears to be specifically due to the depolarization of their mitochondrial membrane, a key factor for apoptotic induction. The same was observed with staurosporine, a specific mitochondrion-mediated proapoptotic chemical probe. Conversely, other proapoptotic stimuli, such as Fas/CD95 or the anti-cancer drug etoposide, did induce significant cell death in wild type cells only. Thus, schematically, mitochondrially dependent stimuli appeared to be more effective in VBL100-cell killing, while 'physiological' stimuli showed the opposite behaviour. Importantly, under steady-state conditions, VBL100 cells displayed per se a mitochondrial membrane hyperpolarization that appeared strictly related to their high susceptibility to specific apoptotic stimuli. In conclusion, the study of a well-established cell model such as that represented by the wt/VBL CEM lymphoid cell line seems to suggest that the multidrug resistance phenotype can specifically sensitize cells towards 'unphysiological', mitochondria-associated cell death cascade or, in the same fashion, it could shift cells from type I (mainly plasma membrane-associated) towards type II (mainly mitochondrial membrane-associated) phenotype.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/fisiologia , Apoptose/fisiologia , Mitocôndrias/fisiologia , Citometria de Fluxo , Humanos , Membranas Intracelulares/fisiologia , Potenciais da Membrana , Permeabilidade , Células Tumorais CultivadasRESUMO
Cell volumes decreased in HeLa cells as a function of time after seeding during exponential growth. Cell volume distributions revealed the presence of two cell populations in all stages of growth. When cells approached confluence, the ratio of the two populations abruptly shifted towards that characterised by the smallest volume. Percentages of G1-, S- and G2 + M-phase cells were also measured and it was found that G1 frequency increased as a function of cell density during exponential growth. Intracellular sodium concentration, [Na]i was monitored by 23Na NMR in the presence of 5 mM dysprosium (III) tripolyphosphate. [Na]i increased from 22.8 to 59.0 mM in cells from the second to the seventh day after seeding. Treatment with lonidamine, an antitumoral drug that it is known to slow down cell growth by affecting aerobic glycolysis, produced a complete block of cell progression after a few days of treatment. The progression of cell volume distributions towards smaller volumes and the increase in internal sodium concentration as a function of time after seeding were also affected by the drug. These phenomena were related to the existence of a subpopulation of mitotically inactive G1-phase cells during exponential growth, pointing out that a density-dependent cellular mechanism regulates the cell cycling in HeLa cells.
Assuntos
Antineoplásicos/farmacologia , Indazóis/farmacologia , Sódio/metabolismo , Divisão Celular/efeitos dos fármacos , Tamanho Celular , Fase G1 , Células HeLa , Humanos , Espectroscopia de Ressonância Magnética , Isótopos de SódioAssuntos
Antígeno Prostático Específico/sangue , Autoanálise , Humanos , Imunoensaio , Medições Luminescentes , Masculino , Antígeno Prostático Específico/metabolismo , Ligação Proteica , Kit de Reagentes para Diagnóstico , Análise de Regressão , alfa 1-Antiquimotripsina/sangue , alfa 1-Antiquimotripsina/metabolismoRESUMO
A key role has been proposed for reactive oxygen species (ROS) in chronic obstructive pulmonary disease (COPD). Aim of the present work was to evaluate possible implications of ROS in the integrity and function of the cell type mainly involved in oxygen uptake and delivery to the peripheral tissues: the erythrocyte. Red blood cells (RBCs) were thus collected from blood samples from COPD patients. Furthermore, blood samples from the same patients treated with the antioxidizing drug of widespread use in such disease i.e., N-acetylcysteine (NAC), were also considered. Morphometric and analytical cytology studies were then conducted. We report herein that: (i) alterations of RBC ultrastructure were detectable in RBCs from COPD patients, that (ii) relevant changes of spectrin cytoskeleton and glycophorin expression were also found and that (iii) NAC treatment was capable of significantly counteracting these changes. These results are consistent with a reappraisal of the role of RBCs in this disease.
Assuntos
Acetilcisteína/farmacologia , Eritrócitos/fisiologia , Pneumopatias Obstrutivas/sangue , Idoso , Eritrócitos/efeitos dos fármacos , Eritrócitos/ultraestrutura , Glicoforinas/metabolismo , Humanos , Técnicas In Vitro , Microscopia Eletrônica de Varredura , Espécies Reativas de Oxigênio/fisiologia , Valores de ReferênciaRESUMO
CD95 (APO-1/Fas) is a member of the tumor necrosis factor receptor family, which can trigger apoptosis in a variety of cell types. However, little is known of the mechanisms underlying cell susceptibility to CD95-mediated apoptosis. Here we show that human T cells that are susceptible to CD95-mediated apoptosis, exhibit a constitutive polarized morphology, and that CD95 colocalizes with ezrin at the site of cellular polarization. In fact, CD95 co-immunoprecipitates with ezrin exclusively in lymphoblastoid CD4(+) T cells and primary long-term activated T lymphocytes, which are prone to CD95-mediated apoptosis, but not in short-term activated T lymphocytes, which are refractory to the same stimuli, even expressing equal levels of CD95 on the cell membrane. Pre-treatment with ezrin antisense oligonucleotides specifically protected from the CD95-mediated apoptosis. Moreover, we show that the actin cytoskeleton integrity is essential for this function. These findings strongly suggest that the CD95 cell membrane polarization, through an ezrin-mediated association with the actin cytoskeleton, is a key intracellular mechanism in rendering human T lymphocytes susceptible to the CD95-mediated apoptosis.
Assuntos
Citoesqueleto de Actina/metabolismo , Apoptose/fisiologia , Fosfoproteínas/metabolismo , Linfócitos T/citologia , Receptor fas/metabolismo , Proteínas Sanguíneas/metabolismo , Western Blotting , Polaridade Celular , Células Cultivadas , Proteínas do Citoesqueleto/metabolismo , Citometria de Fluxo , Imunofluorescência , Humanos , Imuno-Histoquímica , Proteínas de Membrana/metabolismo , Proteínas dos Microfilamentos/metabolismo , Microscopia Eletrônica de Varredura , Microscopia de Vídeo , Oligonucleotídeos Antissenso , Ligação Proteica , Linfócitos T/metabolismo , Receptor fas/fisiologiaRESUMO
Type I Interferon (IFN) and all-trans retinoic acid (RA) inhibit cell proliferation of squamous carcinoma cell lines (SCC). Examinations of growth-affected cell populations show that SCC lines ME-180 and SiHa treated with IFN-beta undergo a specific slower progression through the S phase that seems to trigger cellular death. In combination treatment RA potentiates IFN-beta effect in SCC ME-180 but not in SiHa cell line, partially resistant to RA antiproliferative action. RA added as single agent affects cell proliferation differently by inducing a slight G1 accumulation. The IFN-beta-induced S phase lengthening parallels the increased expression of PML, a nuclear phosphoprotein specifically up-regulated at transcriptional level by IFN, whose overexpression induces cell growth inhibition and tumor suppression. We report that PML up-regulation may account for the alteration of cell cycle progression induced by IFN-beta in SCC by infecting cells with PML-PINCO recombinant retrovirus carrying the PML-3 cDNA under the control of the 5' LTR. In fact PML overexpression reproduces the IFN-beta-induced S phase lengthening. These findings provide important insight into the mechanism of tumor suppressing function of PML and could allow PML to be included in the pathways responsible for IFN-induced cell growth suppression.
Assuntos
Antineoplásicos/farmacologia , Carcinoma de Células Escamosas/patologia , Interferon Tipo I/farmacologia , Proteínas de Neoplasias/biossíntese , Proteínas Nucleares , Fase S/efeitos dos fármacos , Fatores de Transcrição/biossíntese , Neoplasias do Colo do Útero/patologia , Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/metabolismo , Divisão Celular/efeitos dos fármacos , DNA de Neoplasias/biossíntese , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inibidores do Crescimento/administração & dosagem , Inibidores do Crescimento/farmacologia , Humanos , Interferon Tipo I/administração & dosagem , Proteínas de Neoplasias/genética , Proteína da Leucemia Promielocítica , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Proteínas Recombinantes , Fatores de Transcrição/genética , Tretinoína/administração & dosagem , Tretinoína/farmacologia , Células Tumorais Cultivadas , Proteínas Supressoras de Tumor , Regulação para Cima/efeitos dos fármacos , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/metabolismoRESUMO
We investigated the effect of vpr, physiologically expressed during the course of an acute HIV-1 infection, on the response of infected cells to apoptotic stimuli as well as on the HIV-induced apoptosis. At 48 h after infection, Jurkat cells exhibited a lower susceptibility to undergo apoptosis with respect to uninfected cells. This effect was not observed following infection with either a vpr-mutated virus or a wild-type strain in the presence of antisense oligodeoxynucleotides targeted at vpr mRNA. Single-cell analysis, aimed at simultaneously identifying apoptotic and infected cells, revealed that resistance to apoptosis correlated with productive infection. Notably, vpr-dependent protection from induced apoptosis was also observed in HIV-1-infected PBMC. In contrast, at later stages of infection, a marked increase in the number of cells spontaneously undergoing apoptosis was detected in infected cultures. This virus-induced apoptosis involved vpr expression and predominantly occurred in productively infected cells. These results indicate that HIV-1 vpr can exert opposite roles in the regulation of apoptosis, which may depend on the level of its intracellular expression at different stages of HIV-1 infection. The dual function of vpr represents a novel mechanism in the complex strategy evolved by HIV to influence the turnover of T lymphocytes leading to either viral persistence or virus release and spreading.
Assuntos
Apoptose/imunologia , Produtos do Gene vpr/fisiologia , HIV-1/fisiologia , Linfócitos T/citologia , Linfócitos T/virologia , Doença Aguda , Apoptose/efeitos dos fármacos , Cicloeximida/farmacologia , Produtos do Gene vpr/antagonistas & inibidores , Produtos do Gene vpr/biossíntese , Produtos do Gene vpr/genética , Infecções por HIV/imunologia , Infecções por HIV/patologia , Infecções por HIV/virologia , Humanos , Marcação In Situ das Extremidades Cortadas , Células Jurkat/citologia , Células Jurkat/efeitos dos fármacos , Células Jurkat/imunologia , Células Jurkat/virologia , Oligodesoxirribonucleotídeos Antissenso/farmacologia , Fenótipo , RNA Mensageiro/antagonistas & inibidores , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Fator de Necrose Tumoral alfa/farmacologia , Latência Viral/imunologia , Produtos do Gene vpr do Vírus da Imunodeficiência HumanaRESUMO
Galectins are a family of proteins involved in several cell processes, including their survival and death. Galectin-3 has in particular been described as an anti-apoptotic molecule entangled with a number of subcellular activities including anoikis resistance. In this work we partially address the mechanisms underlying this activity pointing at two key factors in injury progression: the alteration of mitochondrial membrane potential and the formation of reactive oxygen species. Overexpression of galectin-3 appears in fact to exert a protective effect towards both these events. On the basis of these data, we propose a reappraisal of the role of galectin-3 as a regulator of mitochondrial homeostasis.
Assuntos
Antígenos de Diferenciação/metabolismo , Glicoproteínas de Membrana/metabolismo , Mitocôndrias/fisiologia , Morte Celular/fisiologia , Feminino , Galectina 3 , Homeostase , Humanos , Membranas Intracelulares/fisiologia , Potenciais da Membrana , Microscopia Eletrônica de Varredura , Mitocôndrias/ultraestrutura , Oxirredução , Espécies Reativas de Oxigênio/metabolismo , Células Tumorais Cultivadas , Fator de Necrose Tumoral alfa/farmacologia , Vitamina K/farmacologiaRESUMO
Galectin-3 is a carbohydrate-binding protein endowed with affinity for beta-galactosides. It plays a role in cell-cell and cell-matrix interactions. Furthermore, it has been hypothesized to be involved in tumor progression and metastasis. To address the role of galectin-3 in the invasive and metastatic processes, we stably overexpressed galectin-3 in human breast carcinoma cell lines, and we evaluated the influence of elevated galectin-3 expression on several cell features, including cellular homotypic and heterotypic interactions and cell survival. No differences in various parameters related with cell growth features and proliferation were detected. By contrast, we found that galectin-3 overexpressing cells, with respect to low galectin-3 expressing cells, exerted: (1) a significantly enhanced adhesion to laminin, fibronectin and vitronectin exerted both directly or via increased expression of specific integrins, e.g., alpha-4 and beta-7; (2) a remodeling of those cytoskeletal elements associated with cell spreading, i.e., microfilaments; (3) an enhanced survival upon exposure to different apoptotic stimuli, such as cytokine and radiation. Collectively, our results indicate that overexpression of galectin-3 may play a role in tumor cell invasion and metastasis by specifically influencing cell adhesion to the extracellular matrix. This may confer selective survival advantage and resistance to the particular homeless-induced apoptosis called anoikia.