Cyclophosphamide Detoxification Research Articles

Cytotoxic responses of the anticancer drug cyclophosphamide in the mussel Mytilus galloprovincialis and comparative sensitivity with human cells lines

The rise of cancer cases worldwide led to an increase in production and consumption of anticancer drugs, that ultimately end up in the marine environment and are accumulated in aquatic organisms. Cyclophosphamide (CP) is a cytotoxic alkylating agent frequently prescribed in cancer treatments. This study assess ecotoxicological effects of CP on mussels Mytilus galloprovincialis, through in vivo and ex vivo approaches and compares the sensitivity of mussel haemocytes with well-established human cell lines (RPE and HeLa). Mussels were exposed in vivo to CP (1000 ng L−1) and several biomarkers analysed in gills and digestive glands namely neurotoxicity (AChE activity), oxidative stress (GPx activity), biotransformation (GST activity), lipid peroxidation (LPO) and apoptosis (caspase activity), whereas genotoxicity was determined in mussels’ haemocytes. Cytotoxicity was also assessed in haemocytes (in vivo and ex vivo) and human cell lines (in vitro) exposed to a range of CP concentrations (50, 100, 250, 500 and 1000 ng L−1) over 24 h, via neutral red assay.In in vivo exposure, detoxification of CP did not efficiently occur in the gills while in digestive glands GPx and GST activities were induced, jointly with a decrease in lipid peroxidation, indicating a potential outcome of the protective antioxidant mechanisms, whereas no apoptosis was noted. Moreover, cytotoxicity and DNA damage were detected in haemocytes. The ex vivo exposure haemocytes to CP caused cytotoxicity (from 100 ng L−1), whereas no effects occurred in human cell lines. This suggests that, at relevant environmental concentrations, CP cause subtle and irreversible impacts on M. galloprovincialis.

Effect of hydro-alcoholic extract of ginseng on cyclophosphamide detoxification in liver tissue of adult rats

Effect of hydro-alcoholic extract of ginseng on cyclophosphamide detoxification in liver tissue of adult rats

Effect of hydro-alcoholic extract of ginseng on cyclophosphamide detoxification in ovary tissue of female adult rats

Effect of hydro-alcoholic extract of ginseng on cyclophosphamide detoxification in ovary tissue of female adult rats

Effects of amifostine on liver oxidative stress caused by cyclophosphamide administration to rats.

Cyclophosphamide is an inactive cytostatic, which is metabolised into active metabolites mainly in the liver. During bioactivation, reactive oxygen species (ROS) are also formed, which can modify the components of both healthy and neoplastic cells leading to decreased antioxidative capacity. Amifostine is a drug that can inactivate ROS. The aim of the present study was to evaluate the influence of amifostine on the antioxidative system of the liver of rats exposed to cyclophosphamide. Intraperitoneal administration of cyclophosphamide was found to decrease the activity of liver antioxidative enzymes, i.e. superoxide dismutase, glutathione peroxidase and glutathione reductase, and to increase catalase activity. Amifostine slightly influenced antioxidative enzyme activity, causing a significant increase only in superoxide dismutase activity. Co-administration of cyclophosphamide and amifostine nearly prevented changes in activities of superoxide dismutase, glutathione reductase and catalase, as well as to a high degree of glutathione peroxidase. Cyclophosphamide also evoked a decrease in the level of non-enzymatic antioxidants, such as reduced glutathione and vitamins C, E and A, as well as total antioxidant status. Administration of amifostine alone caused a significant increase in non-enzymatic antioxidant level that resulted in an increase in total antioxidant status. Administration of amifostine together with cyclophosphamide to a large extent prevented changes in the evaluated non-enzymatic antioxidative parameters, decreasing values of their concentration to the values of control group. Changes of liver antioxidative abilities during detoxification of cyclophosphamide were accompanied by intensified lipid peroxidation, manifested by an increase in concentration of products such as malondialdehyde and 4-hydroxynonenal. Amifostine caused the inhibition of lipid peroxidation in the liver of both control and cyclophosphamide-treated rats. In conclusion, our results suggest that amifostine significantly protects liver antioxidant properties from changes caused by cyclophosphamide treatment and in consequence prevents oxidative stress and phospholipid peroxidative damage.

Mechanisms of Resistance to the Toxicity of Cyclophosphamide

Resistance to cyclophosphamide therapy continues to be a major reason for treatment failure. This chapter covers some of the mechanisms implicated in resistance to the toxic and mutagenic effects of cyclophosphamide therapy in the laboratory and clinic. Since resistance is likely to be the result of a number of interrelating factors, this chapter evaluates the contribution of both glutathione and DNA repair processes to cyclophosphamide resistance. Glutathione appears to be involved directly in the detoxification of cyclophosphamide and metabolites and may play a more indirect role in other processes. The ability of the cell to repair cyclophosphamide-induced DNA lesions, possibly through nucleotide excision repair or other processes, may be a key contributor to drug resistance. Interestingly, the presence of the repair enzyme, O6-alkylguanine-DNA alkyltransferase, long thought to be involved with resistance to methylating and chloroethylating agents, may also contribute to resistance to the cytotoxic and mutagenic effects of cyclophosphamide.

Detoxification of cyclophosphamide by human aldehyde dehydrogenase isozymes

In in vitro studies, no turnover of aldophosphamide and mafosfamide was observed with the tumor-specific aldehyde dehydrogenase 3 isozyme (ALDH3) isolated from human stomach mucosa as well as from lung (A549) and pharynx (UMSCC2) carcinoma cell lines. Only the human liver cytosolic ALDH preparation (ALDH1) showed any significant oxidation of aldophosphamide and mafosfamide.

Cyclophosphamide metabolism in the primary immune organs of the chick: Assays of drug activation, P450 expression, and aldehyde dehydrogenase

Several diagnostic catalytic assays were used to determine whether organ-specific metabolic activation or detoxification of cyclophosphamide (CP) contributes to the selective toxicity of CP directed towards differentiating B cells as compared to T cells in the developing chicken. An assay for the alkylation of 4-[p-nitrobenzyl] pyridine (NBP) was used to assess comparative levels of CP activation products generated from microsomal preparations from liver, bursa of Fabricius (B cells), and thymus (T cells) of day-old chicks. Three catalytic assays were used to characterize and compare cytochrome P450-associated enzyme activities in neonatal hepatic and lymphoid tissues. Aldrin epoxidase (AE) was used to detect phenobarbital (PB)-inducible P450 activity. Ethoxyresorufin-O-deethylase (EROD) and aryl hydrocarbon hydroxylase (AHH) were used for the evaluation of polycyclic aromatic hydrocarbon (PAH)-inducible P450 activities in control and PB- or 3,3',4,4'-tetrachlorobiphenyl (TCB)-induced animals. Using the NBP assay, basal and PB-induced CP activation were observed using chick liver microsomes. However, no evidence of CP activation from immune organ microsomes was observed in control, PB-, or TCB-induced chicks. Basal and PB-induced AE activities were observed in thymus, but not bursa, and represented less than 1% of basal liver activity. EROD activity was detected in TCB-induced samples from both thymus and bursa, the thymus having the greater activity. Activities of aldehyde dehydrogenase (ALDH), an enzyme involved in CP detoxification, were about equal in cytosolic fractions from the bursa and thymus. These studies suggest strongly that tissue-specific differences in metabolic capacities are not the major factors governing the selective toxicity of CP directed towards differentiating B lymphocytes in vivo.

Metabolism of high doses of cyclophosphamide.

The excretion of cyclophosphamide and the enzymatically derived metabolites 4-ketocyclophosphamide and carboxyphosphamide has been measured in four patients after the administration of cyclophosphamide (5 g). At this dose the enzymes responsible for the biotransformation and detoxification of cyclophosphamide are not saturated. In two patients the metabolite profile was unaffected by a previous high dose of cyclophosphamide and in one patient a small primary dose did not alter metabolism.