RESUMO
To determine the chronic skin effects caused by the interaction of infrared and ultraviolet B radiations, male Rattus norvegicus (Wistar) (2 months old) were exposed for 15 days to infrared radiation (600-1500 nm, with a peak at 1000 nm, n = 12) for 30 min (1080 J cm(-2) ) (IRo); to ultraviolet B radiation (peak emission at 313 nm, n = 9) for 90 min (55.08 J cm(-2) ) (UVB); to infrared radiation followed after 90 min by ultraviolet B (n = 6) (IRUVB) and to ultraviolet B followed after 90 min by infrared radiation (n = 9) (UVBIR). Skin samples were collected and histopathological analysis showed the presence of acanthosis, parakeratotic and orthokeratotic hyperkeratosis, intraepidermal pustules, keratin pearls, detachment of epidermis, collagen necrosis, inflammatory infiltrate, vasodilation, basal cell vacuolization and superficial dermis degeneration both in UVB and UVBIR treatments. IRUVB animals showed the same characteristics as above except for parakeratotic hyperkeratosis, keratin pearls and superficial dermis degeneration. To conclude, infrared radiation exposure after ultraviolet B irradiation increases skin damage without protecting the tissue, while infrared radiation exposure before ultraviolet B irradiation showed a protective effect against ultraviolet skin damage.
Assuntos
Raios Infravermelhos , Pele/efeitos da radiação , Raios Ultravioleta , Animais , RatosRESUMO
Onion (Allium cepa) is being studied as a potential anticancer agent, but little is known regarding its effect in multidrug resistance (MDR) cells. In this work, the cytotoxicity of crude onion extract (OE) and fractioned extract (aqueous, methanolic and ethyl acetate), as well as some onion compounds (quercetin and propyl disulfide) were evaluated in Lucena MDR human erythroleukemic and its K562 parental cell line. The capacity of OE to induce apoptosis and/or necrosis in these cells, the possible participation of oxidative stress and DNA damage were also assessed. Similar sensitivities were obtained for both tumoral cells, however only OE caused significant effects in the cells. In K562 cells, a significant increase of apoptosis was verified while the Lucena cells experienced a significant increase of necrosis. An antioxidant capacity was verified for OE discarding oxidative damage. However, OE provoked similar significant DNA damage in both cell lines. Thus, the OE capacity to overcome the MDR phenotype suggests anti-MDR action of OE.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Cebolas/química , Extratos Vegetais/farmacologia , Apoptose , Dano ao DNA , Dissulfetos/análise , Dissulfetos/farmacologia , Humanos , Células K562/efeitos dos fármacos , Dose Letal Mediana , Necrose , Fenótipo , Quercetina/análise , Quercetina/farmacologia , Fatores de TempoRESUMO
The K562 cell line (chronic myeloid leukemia), sensitive to chemotherapy (non-MDR), and the Lucena cell line, resistant to chemotherapy (MDR) were investigated. The results suggest that both cell lines possess CD34+CD38- profiles of hematopoietic stem cell markers. The promoter regions of ABCB1, ABCG2 and ABCC1 genes contain binding sites for the Oct-4 transcripton factor, which is also considered a marker of tumor stem cells. Lucena cells showed an over-expression of the ABCB1 gene and a high expression of the Oct-4, ABCG2 and ABCC1 genes as compared to K562 cells.
Assuntos
Biomarcadores Tumorais/genética , Resistência a Múltiplos Medicamentos/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Células-Tronco Neoplásicas/metabolismo , ADP-Ribosil Ciclase 1/genética , ADP-Ribosil Ciclase 1/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/genética , Antígenos CD34/genética , Antígenos CD34/metabolismo , Antígenos de Superfície/genética , Antígenos de Superfície/metabolismo , Sítios de Ligação , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Resistência a Múltiplos Medicamentos/fisiologia , Resistencia a Medicamentos Antineoplásicos/genética , Regulação Leucêmica da Expressão Gênica , Humanos , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Proteínas de Neoplasias/genética , Células-Tronco Neoplásicas/patologia , Fator 3 de Transcrição de Octâmero/genética , Fator 3 de Transcrição de Octâmero/metabolismo , Regiões Promotoras GenéticasRESUMO
Onion (Allium cepa) is being studied as a potential anticancer agent, but little is known regarding its effect in multidrug resistance (MDR) cells. In this work, the cytotoxicity of crude onion extract (OE) and fractioned extract (aqueous, methanolic and ethyl acetate), as well as some onion compounds (quercetin and propyl disulfide) were evaluated in Lucena MDR human erythroleukemic and its K562 parental cell line. The capacity of OE to induce apoptosis and/or necrosis in these cells, the possible participation of oxidative stress and DNA damage were also assessed. Similar sensitivities were obtained for both tumoral cells, however only OE caused significant effects in the cells. In K562 cells, a significant increase of apoptosis was verified while the Lucena cells experienced a significant increase of necrosis. An antioxidant capacity was verified for OE discarding oxidative damage. However, OE provoked similar significant DNA damage in both cell lines. Thus, the OE capacity to overcome the MDR phenotype suggests anti-MDR action of OE.
Assuntos
Humanos , Antineoplásicos Fitogênicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Cebolas/química , Extratos Vegetais/farmacologia , Apoptose , Dano ao DNA , Dissulfetos/análise , Dissulfetos/farmacologia , /efeitos dos fármacos , Necrose , Fenótipo , Quercetina/análise , Quercetina/farmacologia , Fatores de TempoRESUMO
The objective of this study was to evaluate the time-course effects of UV-B exposure on expression of genes involved in the DNA repair system of zebrafish (Danio rerio) hepatocytes, a highly competent species in terms of damage repair induced by UV radiation. For gene expression analysis (RT-PCR), cells were exposed to 23.3 mJ cm(-2) UV-B, which was the dose that affected viable cell number (reduction of 30% when compared with the control group) and produced no visual alteration on cell morphology. The early response observed (6 h) showed induction in the expression of the CDKI gene (cyclin-dependent kinase inhibitor) and genes related to DNA damage repair (mainly XPC and DDB2), while the late response observed (24 h) was more related to up-regulation of p53 and genes involved in cell cycle arrest (gadd45a, cyclinG1). In all times analyzed, the anti-apoptotic gene Bcl-2 was down-regulated. Another interesting result observed was the up-regulation of the Apex-1 gene after UV-B exposure, which could indicate the induction of oxidative lesions in the DNA molecule. In conclusion, these results demonstrate an activation of the DNA repair system in hepatocytes of zebrafish exposed to UV-B radiation, mainly involving the participation of p53.
Assuntos
Reparo do DNA/genética , Regulação da Expressão Gênica/efeitos da radiação , Hepatócitos/metabolismo , Hepatócitos/efeitos da radiação , Raios Ultravioleta , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , Animais , Proteína Quinase CDC2/genética , Proteína Quinase CDC2/metabolismo , Linhagem Celular , Ciclina G , Ciclinas/genética , Ciclinas/metabolismo , Dano ao DNA/genética , Cinética , Fatores de TempoRESUMO
Three crude extracts of Aplysina caissara, a marine sponge endemic to Brazil, were tested against a hepatoma cell line and Mycobacterium tuberculosis. The results demonstrate that all extracts are toxic and capable of inhibiting cellular growth. Additionally, the extracts produced morphological aberrations and inhibited cell attachment to culture substrates. These effects were dose/time dependent. Our results also suggest that reactive oxygen species (ROS) production is not involved in the cytotoxic processes levied by the extracts employed in this study and that active metabolites are likely to be present in the polar fractions of the crude extracts. Finally, our results indicate that all three extracts exhibit a moderate anti-tuberculosis capacity, and that the removal of an extract's lipid fraction appears to diminish this activity.
Assuntos
Antineoplásicos/farmacologia , Antituberculosos/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Mycobacterium tuberculosis/efeitos dos fármacos , Poríferos , Animais , Antineoplásicos/isolamento & purificação , Antituberculosos/isolamento & purificação , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Concentração Inibidora 50 , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Mycobacterium tuberculosis/crescimento & desenvolvimento , Poríferos/química , Ratos , Espécies Reativas de Oxigênio/metabolismo , Fatores de TempoRESUMO
Polychaeta species like Laeonereis acuta (Nereididae) usually secrete great amounts of mucus that wrap the animal inside. Taking into account that fungi action in the sediment and UV radiation acting on dissolved organic matter in the water produces reactive oxygen species (ROS) like hydrogen peroxide (H(2)O(2)), it was considered that the mucus secretion could represent an antioxidant defense against environmental ROS. Antioxidant enzymes (catalase-CAT; superoxide dismutase-SOD; glutathione peroxidase-GPx and glutathione-S-transferase-GST) and total antioxidant capacity (TOSC) were determined in worms and mucus secretion. Higher (p<0.05) CAT, GPx and TOSC values were registered in mucus samples respect worms, SOD activity was similar (p>0.05) in both kind of samples, and absence of GST activity was observed in mucus samples, suggesting absence of catalyzed phase II reactions. In assays conducted with hepatoma cell lines exposed to H(2)O(2), it was verified that: (1) mucus co-exposure significantly (p<0.05) lowered DNA damage induced by H(2)O(2); (2) ROS production was significantly (p<0.05) reduced when cells were exposed simultaneously with mucus samples and H(2)O(2) respect H(2)O(2) alone. It can be concluded that the mucus production contributes substantially to the antioxidant defense system of the worm against environmental ROS through the interception or degradation of H(2)O(2), peroxyl and hydroxyl radicals.
Assuntos
Antioxidantes/metabolismo , Muco/metabolismo , Poliquetos/metabolismo , Animais , Catalase/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Contagem de Colônia Microbiana , Dano ao DNA , Poluentes Ambientais/toxicidade , Glutationa Peroxidase/metabolismo , Glutationa Transferase/metabolismo , Peróxido de Hidrogênio/toxicidade , Radical Hidroxila/metabolismo , Muco/enzimologia , Muco/microbiologia , Peróxidos/metabolismo , Poliquetos/enzimologia , Ratos , Espécies Reativas de Oxigênio/toxicidade , Superóxido Dismutase/metabolismoRESUMO
The photoprotector role of pigment dispersion in the melanophores of the crab, Chasmagnathus granulata, against DNA and oxidative damages caused by UV-A and UV-B was investigated. Intact and eyestalkless crabs were used. In eyestalkless crabs, the dorsal epidermis of the cephalothorax (dispersed melanophores) and the epidermis of pereiopods (aggregated melanophores) were analyzed. Intact crabs showed only dispersed melanophores in the two epidermis. Antioxidant enzymes activity and lipoperoxidation content were analyzed after UV-A (2.5 J/cm2) or UV-B (8.6 J/cm2) irradiation. DNA damage was analyzed by single cell electrophoresis (comet) assay, after exposure to UV-B (8.6 J/cm2). UV-A radiation increased the glutatione-S-transferase activity in the pereiopods epidermis of eyestalkless crabs (P<0.05). UV-B radiation induced DNA damage in the dorsal epidermis of eyestalkless crabs (P<0.05). In pereiopod epidermis of eyestalkless crabs, there was no significant difference between control and UV-B-exposed crabs. In the pereiopods epidermis of eyestalkless, the control group showed higher scores of DNA damage and approximately 50% of cellular viability. Because in eyestalkless and irradiated crabs the cellular viability was approximately 5%, it was not possible to observe nuclei for determination of DNA damage. The findings show that melanophores can play a role in the defense against harmful effects of a momentary exposure to UV radiation.
Assuntos
Antioxidantes/efeitos da radiação , Dano ao DNA , Decápodes/enzimologia , Decápodes/efeitos da radiação , Glutationa Transferase/efeitos da radiação , Raios Ultravioleta , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Catalase/efeitos da radiação , Sobrevivência Celular/efeitos da radiação , DNA/efeitos dos fármacos , DNA/efeitos da radiação , Decápodes/química , Relação Dose-Resposta à Radiação , Epiderme/química , Epiderme/efeitos da radiação , Glutationa Transferase/metabolismo , Peroxidação de Lipídeos/efeitos da radiação , Melanóforos/química , Melanóforos/fisiologia , Pigmentos Biológicos/efeitos da radiaçãoRESUMO
Multidrug resistance to chemotherapy is a major obstacle in the treatment of cancer patients. The best characterised mechanism responsible for multidrug resistance involves the expression of the MDR-1 gene product, P-glycoprotein. However, the resistance process is multifactorial. Studies of multidrug resistance mechanisms have relied on the analysis of cancer cell lines that have been selected and present cross-reactivity to a broad range of anticancer agents. This work characterises a multidrug resistant cell line, originally selected for resistance to the Vinca alkaloid vincristine and derived from the human erythroleukaemia cell K562. This cell line, named Lucena 1, overexpresses P-glycoprotein and have its resistance reversed by the chemosensitisers verapamil, trifluoperazine and cyclosporins A, D and G. Furthermore, we demonstrated that methylene blue was capable of partially reversing the resistance in this cell line. On the contrary, the use of 5-fluorouracil increased the resistance of Lucena 1. In addition to chemotherapics, Lucena 1 cells were resistant to ultraviolet A radiation and hydrogen peroxide and failed to mobilise intracellular calcium when thapsigargin was used. Changes in the cytoskeleton of this cell line were also observed