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BACKGROUND: the problem in early diagnosis of sporadic cancer is understanding the individual's risk to develop disease. In response to this need, global scientific research is focusing on developing predictive models based on non-invasive screening tests. A tentative solution to the problem may be a cancer screening blood-based test able to discover those cell requirements triggering subclinical and clinical onset latency, at the stage when the cell disorder, i.e. atypical epithelial hyperplasia, is still in a subclinical stage of proliferative dysregulation. METHODS: a well-established procedure to identify proliferating circulating tumor cells was deployed to measure the cell proliferation of circulating non-haematological cells which may suggest tumor pathology. Moreover, the data collected were processed by a supervised machine learning model to make the prediction. RESULTS: the developed test combining circulating non-haematological cell proliferation data and artificial intelligence shows 98.8% of accuracy, 100% sensitivity, and 95% specificity. CONCLUSION: this proof of concept study demonstrates that integration of innovative non invasive methods and predictive-models can be decisive in assessing the health status of an individual, and achieve cutting-edge results in cancer prevention and management.
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Inteligencia Artificial , Neoplasias , HumanosRESUMEN
The triplet combination of irinotecan, oxaliplatin and fluorouracil is an active frontline regimen in metastatic colorectal cancer, but scarce data exist on its use as salvage treatment. We aimed at assessing its safety and efficacy profiles with its circadian-based administration (chronoIFLO5) as either first- or second-line treatment, within the time-finding EORTC 05011 trial. Five-day chronoIFLO5 was administered every 3 weeks in patients with PS 0, 1 or 2. It consisted of chronomodulated irinotecan (180 mg/sqm), oxaliplatin (80 mg/sqm) and fluorouracil-leucovorin (2800 and 1200 mg/sqm, respectively). For our study, toxicity and antitumour activity were evaluated separately in first- and second-line settings. Primary endpoints included Grade 3-4 toxicity rates, best objective response rate (ORR), progression-free survival (PFS) and overall survival (OS). One-hundred forty-nine and 44 patients were treated in first-line and second-line settings, respectively, with a total of 1138 cycles with median relative dose intensities of about 90%. Demographics were comparable in the two groups. Thirty-six (24.7%) and 10 (22.2%) patients experienced at least one episode of severe toxicity in first line and second line, respectively. Frontline chronoIFLO5 yielded an ORR of 62.3% [95% CI: 54.2-70.4] and resulted in median PFS and OS of 8.7 months [7.5-9.9] and 19.9 months [15.4-24.5]. Corresponding figures in second line were 37.5% [22.5-52.5], 6.7 months [4.8-8.9] and 16.3 months [11.8-20.8]. International and prospective evaluation revealed the favourable safety and efficacy profiles of chronoIFLO5, both as frontline and as salvage treatment against metastatic colorectal cancer. In particular, encouraging activity in second line was observed, with limited haematological toxicity.
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BACKGROUND: Responsiveness to Cetuximab alone can be mediated by an increase of Epidermal Growth factor Receptor (EGFR) Gene Copy Number (GCN). Aim of this study was to assess the role of EGFR-GCN in advanced colorectal cancer (CRC) patients receiving chemotherapy plus Cetuximab. METHODS: One hundred and one advanced CRC patients (43 untreated- and 58 pre-treated) were retrospectively studied by fluorescence in situ hybridization (FISH) to assess EGFR-GCN and by immunohistochemistry (IHC) to determine EGFR expression. Sixty-one out of 101 patients were evaluated also for k-ras status by direct sequencing. Clinical end-points were response rate (RR), progression-free survival (PFS) and overall survival (OS). RESULTS: Increased EGFR-GCN was found in 60/101 (59%) tumor samples. There was no correlation between intensity of EGFR-IHC and EGFR-GCN (p = 0.43). Patients receiving chemotherapy plus Cetuximab as first line treatment had a RR of 70% (30/43) while it was 18% (10/56) in the group with previous lines of therapy (p < 0.0001). RR was observed in 29/60 (48%) of patients with increased EGFR-GCN and in 6/28 (21%) in those without (p = 0.02). At multivariate analyses, number of chemotherapy lines and increased EGFR-GCN were predictive of response; EGFR-IHC score, increased EGFR-GCN and number of chemotherapy lines were significantly associated with a significant better PFS. Response to therapy was the only prognostic predictive factor for OS. In the 60 patients analyzed for k-ras mutations, number of chemotherapy lines, increased EGFR-GCN and k-ras wild type status predicted a better PFS. CONCLUSION: In metastatic CRC patients treated with chemotherapy plus Cetuximab number of chemotherapy lines and increased EGFR-GCN were significantly associated with a better clinical outcome, independent of k-ras status.
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Anticuerpos Monoclonales/uso terapéutico , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Receptores ErbB/genética , Dosificación de Gen/genética , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Monoclonales Humanizados , Cetuximab , Neoplasias Colorrectales/patología , Supervivencia sin Enfermedad , Femenino , Humanos , Hibridación Fluorescente in Situ , Masculino , Persona de Mediana Edad , Análisis Multivariante , Estadificación de Neoplasias , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas p21(ras) , Resultado del Tratamiento , Proteínas ras/metabolismoRESUMEN
Clinical studies based on novel rationales and mechanisms of action of chemotherapy agents and cytokines can contribute to the development of new concepts and strategies of antitumor combination therapies. In previous studies, we investigated the paradoxical immunostimulating effects of some chemotherapeutics and the immunoadjuvant activity of interferon alpha (IFN-α) in preclinical and clinical models, thus unraveling novel rationales and mechanisms of action of chemotherapy agents and cytokines for cancer immunotherapy. Here, we carried out a randomized, phase II clinical trial, in which we analyzed the relapse-free (RFS) and overall survival (OS) of 34 completely resected stage III-IV melanoma patients, treated with peptide-based vaccination (Melan-A/MART-1 and NY-ESO-1) in combination with IFN-α2b, with (arm 2) or without (arm 1) dacarbazine preconditioning. All patients were included in the intention-to-treat analysis. At a median follow-up of 4.5 years (interquartile range, 15.4-81.0 months), the rates of RFS were 52.9 and 35.3% in arms 1 and 2, respectively. The 4.5-year OS rates were 68.8% in arm 1 and 62.7% in arm 2. No significant differences were observed between the two arms for both RFS and OS. Interestingly, the RFS and OS curves remained stable starting from 18 and 42 months, respectively. Grade 3 adverse events occurred in 5.9% of patients, whereas grade 4 events were not observed. Both treatments induced a significant expansion of vaccine-specific CD8+ T cells, with no correlation with the clinical outcome. However, treatment-induced increase of polyfunctionality and of interleukin 2 production by Melan-A-specific CD8+ T cells and expansion/activation of natural killer cells correlated with RFS, being observed only in nonrelapsing patients. Despite the recent availability of different therapeutic options, low-cost, low-toxic therapies with long-lasting clinical effects are still needed in patients with high-risk resected stage III/IV melanoma. The combination of peptide vaccination with IFN-α2b showed a minimal toxicity profile and resulted in encouraging RFS and OS rates, justifying further evaluation in clinical trials, which may include the use of checkpoint inhibitors to further expand the antitumor immune response and the clinical outcome. Clinical Trial Registration: https://www.clinicaltrialsregister.eu/ctr-search/search, identifier: 2008-008211-26.
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HL-60 leukemia cells, Rat-1 fibroblasts and WI-38 diploid fibroblasts were exposed for 24-72 h to 0.5-1.0-mT 50-Hz extremely low frequency electromagnetic field (ELF-EMF). This treatment induced a dose-dependent increase in the proliferation rate of all cell types, namely about 30% increase of cell proliferation after 72-h exposure to 1.0 mT. This was accompanied by increased percentage of cells in the S-phase after 12- and 48-h exposure. The ability of ELF-EMF to induce DNA damage was also investigated by measuring DNA strand breaks. A dose-dependent increase in DNA damage was observed in all cell lines, with two peaks occurring at 24 and 72 h. A similar pattern of DNA damage was observed by measuring formation of 8-OHdG adducts. The effects of ELF-EMF on cell proliferation and DNA damage were prevented by pretreatment of cells with an antioxidant like alpha-tocopherol, suggesting that redox reactions were involved. Accordingly, Rat-1 fibroblasts that had been exposed to ELF-EMF for 3 or 24 h exhibited a significant increase in dichlorofluorescein-detectable reactive oxygen species, which was blunted by alpha-tocopherol pretreatment. Cells exposed to ELF-EMF and examined as early as 6 h after treatment initiation also exhibited modifications of NF kappa B-related proteins (p65-p50 and I kappa B alpha), which were suggestive of increased formation of p65-p50 or p65-p65 active forms, a process usually attributed to redox reactions. These results suggest that ELF-EMF influence proliferation and DNA damage in both normal and tumor cells through the action of free radical species. This information may be of value for appraising the pathophysiologic consequences of an exposure to ELF-EMF.
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Proliferación Celular/efectos de la radiación , Daño del ADN/efectos de la radiación , Desoxiguanosina/análogos & derivados , Oxidación-Reducción , 8-Hidroxi-2'-Desoxicoguanosina , Animales , Antioxidantes/metabolismo , Antioxidantes/farmacología , Western Blotting , Línea Celular Tumoral , Aductos de ADN , Desoxiguanosina/metabolismo , Relación Dosis-Respuesta en la Radiación , Campos Electromagnéticos , Fibroblastos/metabolismo , Citometría de Flujo , Fluoresceínas/farmacología , Radicales Libres , Células HL-60 , Humanos , FN-kappa B/metabolismo , Especies Reactivas de Oxígeno , Factores de Tiempo , alfa-Tocoferol/farmacologíaRESUMEN
The circadian system is composed of a set of clock-genes including PERIOD, CLOCK, BMAL1 and CRY. Disrupting this system promotes cancer development and progression. The expression levels of miR-206, miR-219, miR-192, miR-194 and miR-132 regulating clock-genes and three functional polymorphisms rs11133373 C/G, rs1801260 T/C, rs11133391 T/C in CLOCK sequence were associated with the survival of 83 mCRC patients (50 males and 33 females). Longer overall survival (OS) was observed in women compared to men, 50 versus 31 months. This difference was associated with rs11133373 C/C genotype (p = 0.01), rs1801260 T/C+C/C genotype (p = 0.06) and rs11133391 T/T genotype (p = 0.06). Moreover women expressing high levels (H) of miR-192 (p = 0.03), miR-206 (p = 0.003), miR-194 (p = 0.02) and miR-219 (p = 0.002) had a longer OS compared to men. In women longer OS was reinforced by the simultaneous presence of two or more H-miR, 58 months versus 15 months (p = 0.0008); in this group of women an OS of 87 months was reached with the additional presence of rs11133391T/T genotype (p = 0.02). In this study we identified a subgroup of female patients who seems to have a better prognosis. Personalized medicine should prospectively take into account both genetic and gender differences.
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CONCLUSION: The results of this study indicate that vascular endothelial growth factor (VEGF) may be an important regulator of the vascular network of the inner ear and suggest that the VEGF signalling pathway may play a role in pathophysiologic conditions. OBJECTIVE: In order to clarify the role of vascular growth factor in the modulation of the vascular network of the cochlea, we studied the expression of VEGF and its receptors-fms-like tyrosine kinase (Flt-1) and foetal liver kinase (Flk-1)-in the inner ear of 3-month-old rodents of different species: C57BL/6J mice, Wistar albino rats and Hartley albino guinea pigs. MATERIAL AND METHODS: Qualitative immunohistochemical studies were performed by using specific antibodies to VEGF and its receptors on paraffin sections of the cochlea. The expression levels of VEGF and its receptors were quantified by means of Western blot analysis of cochlea protein extracts. RESULTS: We demonstrated that VEGF and its receptors are expressed in the cochlea and described their distribution in the inner ear. In particular, VEGF and Flt-1 are present at the level of the modiolus, spiral ganglion, spiral ligament, basilar membrane, supporting cells, outer and inner hair cells and stria vascularis. Flk-1 was less strongly expressed in the cochlea and was not detected in the organ of Corti.
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Cóclea/irrigación sanguínea , Receptores de Factores de Crecimiento Endotelial Vascular/fisiología , Transducción de Señal/fisiología , Factor A de Crecimiento Endotelial Vascular/fisiología , Animales , Apoptosis/fisiología , División Celular/fisiología , Movimiento Celular/fisiología , Oído Interno/irrigación sanguínea , Endotelio Vascular/fisiología , Cobayas , Ratones , Ratones Endogámicos C57BL , Neovascularización Fisiológica/fisiología , Ratas , Ratas Wistar , Especificidad de la Especie , Receptor 1 de Factores de Crecimiento Endotelial Vascular/fisiología , Receptor 2 de Factores de Crecimiento Endotelial Vascular/fisiología , Vasodilatación/fisiologíaRESUMEN
Possible correlation between the effects of electromagnetic fields (EFs) on voltage-gated Ca(2+) channels, cell proliferation and apoptosis was investigated in neural and neuroendocrine cells. Exposure to 50 Hz EFs significantly enhanced proliferation in human neuroblastoma IMR32 (+40%) and rat pituitary GH3 cells (+38%). In IMR32 cells EF stimulation also inhibited puromycin- and H(2)O(2)-induced apoptosis (-22 and -33%, respectively). EF effects on proliferation and apoptosis were counteracted by Ca(2+) channel blockade. In whole-cell patch-clamp experiments 24-72 h exposure to EFs increased macroscopic Ba(2+)-current density in both GH3 (+67%) and IMR32 cells (+40%). Single-channel recordings showed that gating of L and N channels was instead unaffected, thus suggesting that the observed enhancement of current density was due to increased number of voltage-gated Ca(2+) channels. Western blot analysis of plasma membrane-enriched microsomal fractions of GH3 and IMR32 cells confirmed enhanced expression of Ca(2+) channel subunit alpha(1) following exposure to EFs. These data provide the first direct evidence that EFs enhance the expression of voltage-gated Ca(2+) channels on plasma membrane of the exposed cells. The consequent increase in Ca(2+) influx is likely responsible for the EF-induced modulation of neuronal cell proliferation and apoptosis.
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Apoptosis/efectos de la radiación , Canales de Calcio Tipo L/efectos de la radiación , Canales de Calcio Tipo N/efectos de la radiación , Campos Electromagnéticos , Neuroblastoma/metabolismo , Hipófisis/metabolismo , Animales , Antimetabolitos Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Calcio/metabolismo , Bloqueadores de los Canales de Calcio/farmacología , División Celular/efectos de los fármacos , División Celular/efectos de la radiación , Membrana Celular/química , Membrana Celular/metabolismo , Células Cultivadas , Electrofisiología , Humanos , Peróxido de Hidrógeno/farmacología , Neuroblastoma/patología , Oxidantes/farmacología , Técnicas de Placa-Clamp , Hipófisis/citología , Puromicina/farmacología , RatasRESUMEN
To study the role of Magnesium in the regulation of cell proliferation we characterized the proliferation behaviour of HC-11 mammary epithelial cells that were grown in media containing low to high Mg concentrations. Cells grown under control conditions (0.5 mM Mg in the medium) or in the presence of high (H) Mg (45 mM) displayed similar log-phases and reached confluence in 72h. In the presence of low (L) Mg (0.025 mM) the cells exhibited a reduced growth rate and did not reach confluence at 72h. Intra cellular total Mg increased from 12 to 36h of culture in all cells examined but returned to basal levels in those cells which reached confluence (i.e., control and H-Mg cells). Intra cellular Mg increased independent of mitosis-induced changes of volume and adenine nucleotides pools but correlated with an increased percentage of cells in the S phase and with total nucleic acid contents. These bell-shaped changes of intra cellular Mg were less evident in L-Mg cells, likely due to a combination of low Mg levels in the medium and decreased growth rate. Changes in membrane potential and pH were important factors that contributed to maintaining intra cellular Mg at physiologic levels in the face of increased or decreased availability of extra cellular Mg. H-Mg cells were depolarised and more acidic than control cells; conversely, L-Mg cells showed a pattern of hyperpolarization and alkalinization. These results lend support to the concept that Mg may be involved in regulating cell proliferation, and show that cells maintain adequate levels of intra cellular Mg, and hence their proliferation potential, even under conditions of extreme changes of extra cellular Mg.
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Mama/metabolismo , Células Epiteliales/metabolismo , Regulación de la Expresión Génica , Magnesio/metabolismo , Nucleótidos de Adenina/química , Línea Celular , Proliferación Celular , ADN/química , Citometría de Flujo/métodos , Humanos , Concentración de Iones de Hidrógeno , Magnesio/química , Modelos Estadísticos , Factores de TiempoRESUMEN
Cause-effect relationships between oxidative stress, DNA damage and aging were investigated in WI-38 human diploid fibroblasts at 21, 41 or 58 population doublings (PDs), corresponding to young, middle age or old fibroblasts, respectively. Oxidative DNA damage was evaluated by immunohistochemical detection of 8-hydroxy-2'deoxyguanosine (8-OHdG) adducts or by single cell microgel electrophoresis (COMET assay). Aging was evaluated by growth rate, senescence-associated-beta-galactosidase (SA-beta galactosidase) activity, cell cycle distribution, and expression of p21. Our results demonstrate that (i) oxidative DNA damage is proportional to the age of cells (ii) DNA damage in old/58 PDs cells reflects both an increased susceptibility to oxidative stress, induced by acute exposure to sub-lethal concentrations of hydrogen peroxide (H(2)O(2)), and a reduced efficiency of repair mechanisms. We also show that mild chronic oxidative stress, induced by prolonged exposure to 5 microM H(2)O(2), accelerates aging in fibroblasts. In fact, this treatment increased 8-OHdG levels, SA-beta-galactosidase activity, and G0/G1 cell cycle arrest in middle age/41 PDs, making them similar to H(2)O(2)-untreated old/58 PDs cells. Although other mechanisms may concur in mediating the effects of H(2)O(2), these results lend support to the concept that oxidative stress may be a key determinant of aging. Measurements of oxidative DNA damage might therefore be exploited as reliable marker of cellular aging.
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Senescencia Celular/fisiología , Daño del ADN , Desoxiguanosina/análogos & derivados , 8-Hidroxi-2'-Desoxicoguanosina , Biomarcadores , Ciclo Celular/efectos de los fármacos , Línea Celular , Reparación del ADN , Desoxiguanosina/metabolismo , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Humanos , Peróxido de Hidrógeno/toxicidad , Oxidación-Reducción , Estrés Oxidativo , beta-Galactosidasa/metabolismoRESUMEN
The mechanisms responsible for age-associated hearing loss are still incompletely characterized. In this study, we used a murine model of age-dependent hearing loss and evaluated whether this condition is associated with vascular modifications of the structures of the inner ear. We used old C57BL/6J mice that are affected by rapid and severe age-related hearing loss, and analyzed the expression pattern of vascular endothelial growth factor (VEGF), a prototypical angiogenic cytokine, and its receptors Flt-1 and Flk-1 in the inner ear. We report for the first time morphological and quantitative data about the expression of these crucial angiogenic molecules in the murine cochlea. We also show that in this animal model, cochlear VEGF expression is significantly reduced as a function of age. Our findings provide new evidence of possible interdependent relationships between aging, VEGF, and presbycusis, suggesting that vascular abnormalities might play a role in aging-associated hearing loss, with potentially important fundamental and clinical implications.
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Envejecimiento/fisiología , Cóclea/química , Presbiacusia/metabolismo , Receptores de Factores de Crecimiento Endotelial Vascular/análisis , Factor A de Crecimiento Endotelial Vascular/análisis , Animales , Western Blotting/métodos , Proteínas de la Matriz Extracelular/análisis , Femenino , Inmunohistoquímica/métodos , Masculino , Ratones , Ratones Endogámicos C57BL , Modelos Animales , Cadenas Pesadas de Miosina , Miosina Tipo IIB no Muscular , Tubulina (Proteína)/análisis , Receptor 1 de Factores de Crecimiento Endotelial Vascular , Receptor 2 de Factores de Crecimiento Endotelial Vascular/análisisAsunto(s)
Fenómenos Fisiológicos Celulares , Magnesio/metabolismo , Animales , Apoptosis , Transporte Biológico , División Celular/fisiología , Canales Iónicos/genética , Canales Iónicos/metabolismo , Magnesio/química , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Oxidación-Reducción , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , Transducción de Señal/fisiología , Canales Catiónicos TRPMRESUMEN
Although epidemiologic studies have demonstrated that a high intake of vegetables containing beta-carotene lowers the risk of cancer, recent intervention studies have revealed that beta-carotene supplementation to smokers resulted in a high incidence of lung cancer. We hypothesized that beta-carotene may act as a pro- or anticancerogenic agent by modulating pathways involved in cell growth and that such a modulation may involve a redox mechanism. To test this hypothesis, cell proliferation, apoptosis and redox status were evaluated in undifferentiated and dimethylsulfoxide-differentiated HL-60 cells exposed to beta-carotene. The carotenoid modified cell cycle progression and induced apoptosis in a dose-dependent manner. These effects were more remarkable in undifferentiated cells than in differentiated cells. In accord with these findings, in undifferentiated cells, beta-carotene was more effective in decreasing cyclin A and Bcl-2 expression and in increasing p21 and p27 expression. Neither Bcl-xL nor Bax expression were significantly modified by the carotenoid. From a mechanistic point of view, the delay in cell growth by beta-carotene was highly coincident with the increased intracellular reactive oxygen species production and oxidized glutathione content induced by the carotenoid. Moreover, alpha-tocopherol minimized the effects of beta-carotene on cell growth. These data provide evidence that beta-carotene modulates molecular pathways involved in cell cycle progression and apoptosis and support the hypothesis that a redox mechanism may be implicated. They also suggest that differentiated cells may be less susceptible to the carotenoid than highly neoplastic undifferentiated cells.
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Apoptosis/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Células HL-60/efectos de los fármacos , Células HL-60/metabolismo , Oxidación-Reducción , beta Caroteno/farmacología , Proteínas de Ciclo Celular/metabolismo , División Celular/efectos de los fármacos , Ciclina A/metabolismo , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Inhibidor p27 de las Quinasas Dependientes de la Ciclina , Ciclinas/metabolismo , Dimetilsulfóxido/farmacología , Relación Dosis-Respuesta a Droga , Disulfuro de Glutatión/metabolismo , Células HL-60/citología , Humanos , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Proteínas Supresoras de Tumor/metabolismo , alfa-Tocoferol/farmacología , Proteína X Asociada a bcl-2 , Proteína bcl-XRESUMEN
In this study, we examined possible mechanisms of caspase activation during carotenoid-induced apoptosis in tumor cells. We found that beta-Carotene induces apoptosis by the activation of caspase-3 in human leukemia (HL-60), colon adenocarcinoma (HT-29) as well as melanoma (SK-MEL-2) cell lines. This activation is dose dependent and follows that of caspase-8 and caspase-9. Although caspase-8 cleavage is an early event, reaching its maximum activation at 3 h, caspase-9 reaches its maximum activation only at 6 h. The addition of IETD-CHO, a caspase-8-specific inhibitor, completely prevents beta-Carotene-induced apoptosis, whereas only a partial prevention was observed in the presence of LEHD-CHO, a caspase-9-specific inhibitor. beta-Carotene activates caspase-9 via cytochrome c release from mitochondria and loss of mitochondrial membrane potential (Dym). Concomitantly, a dose-dependent decrease in the antiapoptotic protein Bcl-2 and a dose-dependent increase in the cleaved form of BID (t-BID) are observed. Moreover, NF-kB activation is involved in beta-Carotene-induced caspase cascade. These results support a pharmacological role for beta-Carotene as a candidate antitumor agent and show a possible sequence of molecular events by which this molecule may induce apoptosis in tumor cells.
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Apoptosis/efectos de los fármacos , Caspasas/metabolismo , Neoplasias/patología , beta Caroteno/farmacología , Adenocarcinoma/patología , Proteína Proapoptótica que Interacciona Mediante Dominios BH3 , Proteínas Portadoras/análisis , Caspasa 3 , Caspasa 8 , Caspasa 9 , Neoplasias del Colon/patología , Citocromos c/metabolismo , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Células HL-60/patología , Humanos , Melanoma/patología , Potenciales de la Membrana , Mitocondrias/metabolismo , Mitocondrias/ultraestructura , FN-kappa B/fisiología , Proteínas Proto-Oncogénicas c-bcl-2/análisis , Células Tumorales CultivadasRESUMEN
Human intervention trials have suggested that supplemental beta-carotene resulted in more cancer in smokers, whereas it was protective in non-smokers. However, the mechanisms underlying these effects are still unknown. The aim of this study was to evaluate the effects of an association of cigarette smoke condensate (tar) and beta-carotene on DNA oxidative damage and molecular pathways involved in cell cycle progression and apoptosis in cultured cells. In RAT-1 fibroblasts, tar caused increased levels of 8-hydroxyl-2'-deoxyguanosine (8-OHdG) and this effect was enhanced by the concomitant presence of beta-carotene (0.5-4.0 microM) in a dose- and time-dependent manner. In contrast, beta-carotene alone did not significantly modify it. Fibroblasts treated with tar alone decreased their cell growth with respect to control cells through an arrest of cell cycle progression in the G0/G1 phase and an induction of apoptosis. These effects were accompanied by an increased expression of p53, p21 and Bax and by a decreased expression of cyclin D1. In contrast, fibroblasts treated with tar and beta-carotene, after an initial arrest of cell growth at 12 h, re-entered in cell cycle and were unable to undergo apoptosis at 36 h. Concomitantly, their p53 expression, after an increase at 12 h, progressively returned at basal levels at 36 h by a mechanism independent of Mdm2. Such a decrease was followed by a decrease in p21 and Bax expression and by an increase in cyclin D1 expression. Moreover, the presence of the carotenoid remarkably enhanced cyclooxygenase-2 expression induced by tar. During tar treatment, a depletion of beta-carotene was observed in fibroblasts. The effects of tar and beta-carotene on 8-OHdG levels, cell growth and apoptosis were also observed in Mv1Lu lung, MCF-7 mammary, Hep-2 larynx and LS-174 colon cancer cells. This study supports the evidence for potential detrimental effects of an association between beta-carotene and cigarette smoke condensate.
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Daño del ADN , Desoxiguanosina/análogos & derivados , Nicotiana/efectos adversos , Oxígeno/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2 , Proteína p53 Supresora de Tumor/fisiología , beta Caroteno/fisiología , 8-Hidroxi-2'-Desoxicoguanosina , Animales , Apoptosis , Western Blotting , Ciclo Celular/efectos de los fármacos , División Celular , Línea Celular Tumoral , Células Cultivadas , Ciclina D1/biosíntesis , Desoxiguanosina/biosíntesis , Relación Dosis-Respuesta a Droga , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Fase G1 , Humanos , Ratones , Estrés Oxidativo , Proteínas Proto-Oncogénicas/metabolismo , Ratas , Fase de Descanso del Ciclo Celular , Fumar/efectos adversos , Factores de Tiempo , Proteína p53 Supresora de Tumor/metabolismo , Proteína X Asociada a bcl-2RESUMEN
We demonstrated previously that beta-carotene may affect cell growth by a redox mechanism. The purpose of this study was to determine whether the redox-sensitive transcription factor nuclear factor (NF)-kappaB may be involved in the growth-inhibitory and proapoptotic effects of the carotenoid. To test this hypothesis, human leukemic cells (HL-60) and colon adenocarcinoma cells (LS-174 and WiDr) were treated with beta-carotene, alone or in combination with alpha-tocopherol or N-acetylcysteine, and changes in 1) cell oxidative status, 2) cell growth and apoptosis, 3) DNA-binding activity of NF-kappaB and 4) expression of c-myc, a NF-kappaB target gene involved in apoptosis, were evaluated. In HL-60 cells, beta-carotene induced a significant increase in reactive oxygen species (ROS) production (P < 0.001) and in oxidized glutathione (GSSG) content (P < 0.005) at concentrations >/=10 micro mol/L. These effects were always accompanied by a sustained elevation of NF-kappaB and by a significant inhibition (P < 0.002) of cell growth. NF-kappaB DNA-binding activity increased at 3 h and persisted for at least 48 h. Colon adenocarcinoma cells displayed substantial differences in their sensitivity to beta-carotene, exhibiting increased ROS levels and activation of NF-kappaB at concentrations much lower in LS-174 cells (2.5-5.0 micro mol/L) than in WiDr cells (50-100 micro mol/L). In all cell lines studied, alpha-tocopherol and N-acetylcysteine inhibited the effects of beta-carotene on NF-kappaB, cell growth and apoptosis, and normalized the increased expression of c-myc induced by the carotenoid. These data suggest that the redox regulation of NF-kappaB induced by beta-carotene is involved in the growth-inhibitory and proapoptotic effects of the carotenoid in tumor cells.