Browsing by Subject "Methotrexate"

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    Suppression of antifolate resistance by targeting the myosin va trafficking pathway in melanoma
    (Elsevier, 2014-02-28) Fernández Pérez, Maria Piedad; Sáez Ayala, Magalí; Piñero Madrona, Antonio; Cabezas Herrera, Juan; Montenegro Arce, María Fernanda; Rodríguez López, José Neptuno; Sánchez del Campo Ferrer, Luis; Bioquímica y Biología Molecular A
    Human melanoma is a significant clinical problem. As most melanoma patients relapse with lethal drug-resistant disease, understanding and preventing mechanism(s) of resistance is one of the highest priorities to improve melanoma therapy. Melanosomal sequestration and the cellular exportation of cytotoxic drugs have been proposed to be important melanoma-specific mechanisms that contribute to multidrug resistance in melanoma. Concretely, we found that treatment of melanoma with methotrexate (MTX) altered melanogenesis and accelerated the exportation of melanosomes; however, the cellular and molecular processes by which MTX is trapped into melanosomes and exported out of cells have not been elucidated. In this study, we identified myosin Va (MyoVa) as a possible mediator of these cellular processes. The results demonstrated that melanoma treatment with MTX leads to Akt2-dependent MyoVa phosphorylation, which enhances its ability to interact with melanosomes and accelerates their exportation. To understand the mechanism(s) by which MTX activates Akt2, we examined the effects of this drug on the activity of protein phosphatase 2A, an Akt inhibitor activated by the methylation of its catalytic subunit. Taken together, this study identified a novel trafficking pathway in melanoma that promotes tumor resistance through Akt2/MyoVa activation. Because of these findings, we explored several MTX combination therapies to increase the susceptibility of melanoma to this drug. By avoiding MTX exportation, we observed that the E2F1 apoptotic pathway is functional in melanoma, and its induction activates p73 and apoptosis protease-activating factor 1 following a p53-autonomous proapoptotic signaling event.
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    The combined effect of honey and olive oil against methotrexate mediated hepatotoxicity in rats: A biochemical, histological and immunohistological study
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2019) Alturkistani, Hani A.; Abuzinadah, Osama A.H.; Kelany, Abdelhakeem M.; Aziz, Gamal S. Abd El; Alrafiah, Aziza R.
    Background. Honey and olive oil are natural products that have high nutritional values, and therapeutic properties. Cytotoxic drugs, like methotrexate (MTX) are used to treat malignancies in tumour cells; however, these drugs also have serious side effects that could threaten the patient's life. Aim. To evaluate the potential protective effects of honey and olive oil, administered alone or together, against MTX-induced hepatotoxicity in rats. Methods. Adult male albino rats were divided: Group I: negative control (n=8); II: honey (daily by oral 1.2 g/kg bwt (n=8), III: olive oil (1 ml/day) (n=8), IV: single intraperitoneal injection of MTX (20 mg/kg bwt) (n=8), V: diluted honey for 3 days before injection of MTX (n=8), Group VI: olive oil for 3 days before injection of MTX (n=8), Group VII: both honey and olive oil for 3 days before injection of MTX (n=8). After treatment, rats were sacrified and blood samples were collected to determine liver function parameters, liver tissue used to measure the oxidative (malondialdehyde), antioxidative parameters (superoxide dismutase, catalase and glutathione peroxidase), histological and immunohistochemical techniques. Results. The administration of honey and olive oil exerted a protective effect against MTX-induced hepatotoxicity, as demonstrated by the normalization of the liver enzymes, proteins and total bilirubin and by the histopathological and immunohistological changes observed in the livers. Both agents also reversed the oxidative damage in the liver by decreasing level of MDA levels and increasing the antioxidant related by enzymes in the liver homogenates compared to the control rats. These effects were more evident when the two agents were administered together. Conclusion. The combined intake of honey and olive oil could be hepatoprotective. Co-administration of these agents might form an effective adjuvant therapy and minimize side effects of chemoherapy in cancerous patients.
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    Ultrastructural changes in rat livers perfused in vitro and in vivo with a high dose of methotrexate
    (Murcia : F. Hernández, 2005) Al-Ali, Saad Y.; Hassan, Ibrahim M.; Sadek, S.
    Methotrexate is an antifolate that is widely used in the treatment of malignant tumours and other diseases. The present study was undertaken to examine the short-term effects of high doses of methotrexate (HD-MTX) on the ultrastructure and metabolic activity of isolated rat livers. The authenticity of the druginduced changes was substantiated by the concomitant use of in vivo experiments. Isolated rat livers were infused with HD-MTX via the portal vein for 3 hours (total dose for each liver 2000 mg). For in vivo experiments, each rat received a single intravenous injection of a maximum tolerated dose of MTX (100 mg/kg body weight) that allowed the animals to survive for 3 days. At the end of each experimental period, MTX-treated and control livers were processed for light microscopy (LM), scanning (SEM) and transmission electron (TEM) microscopy. Oxygen consumption and thyroxine metabolism were measured in treated and control isolated livers. With the exception of a few minor differences, the structural changes in the hepatocytes after MTX treatment in vitro and vivo were similar. There were focal changes consisting of disruption of normal hepatic plates and swelling and vacuolation of the hepatocytes, with no clear evidence of restriction to a specific hepatic zone. SEM revealed striking changes in the plasma membrane, the microvillar system, intercellular junctions and the sinusoidal endothelium. TEM revealed disorganized endoplasmic reticulum, dispersion of the polyribosomes, a variety of mitochondrial changes, and glycogen redistribution. In MTX-treated isolated rat livers, the uptake of tetraiodothyronine (T4) was not affected, but triiodothyronine (T3) release was impaired. Oxygen consumption was increased in livers treated with MTX. Employing an organotypic liver perfusion model in conjunction with the in vivo experiment and the use of SEM, TEM and hepatic thyroxine measurements, this investigation revealed that infusion of HD-MTX induced early ultrastructual changes in cell membrane, intercellular junctions and cell organelles and disturbance in the functional integrity of the hepatocytes in isolated rat liver.
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    Ultrastructural evaluation of the effect of N-acetylcysteine on methotrexate nephrotoxicity in rats
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2013) Çaglar, Yıdız; Özgür, Hülya; Matur, Irem; Yenilmez, Ebru Dündar; Tuli, Abdullah; Gönlüsen, Gülfiliz; Polat, Sait
    The aim of this study is to investigate the possible protective effect of N-Acetylcysteine (NAC) against the likely methotrexate (MTX) toxicity on the kidney using ultrastructural together with biochemical data. Moreover, the immunohistochemical detection of Ki67 nuclear antigen is to be evaluated. Fifteen male Wistar albino rats, weighing 240-290 g, were divided into three equal groups: Rats receiving MTX alone, rats receiving MTX plus NAC treatment, and rats comprising the control group. MTX (18 mg/kg/day, body weight) in dissolved physiologic saline was administered intraperitoneally to rats during 3 days. For the MTX plus NAC group, N-Acetylcysteine (300 mg/kg/day, body weight) was administered together with MTX. At the end of the third day, all the rats were killed with cervical dislocation to obtain blood and tissue samples. Application of MTX principally induced prominent large vacuolization in the proximal convoluted tubule cells, and focal thickening in the glomerular basal lamina of some glomeruli. A decrease in tissue SOD (superoxide dismutase) and GSH-Px (glutathione peroxidase), and an increase in serum urea nitrogen and creatinine and in tissue MDA (malondialdehyde) levels were also seen in the MTX group. These changes were significantly reversed in the MTX-plus-NAC-treated group. Most of the vacuoles in the proximal convoluted tubule cells disappeared. Furthermore, an increase in antioxidant enzyme activities, a decrease in serum urea nitrogen and creatinine, and tissue MDA levels were all significant. Additionally, an increase in the number of Ki67 positive- stained cells in proximal tubules was also noted. In conclusion, NAC may be a promising substance against MTX-induced renal damage. It might be useful to use NAC supplementally to minimize MTX-induced