Free radicals and antioxidants in chemotherapy-induced toxicity

Genotoxic, teratotoxic and oral toxic assessments of Antrodia cinnamomea health food product (Leader Deluxe Antrodia cinnamomea®)

Antrodia cinnamomea is a rare and endemic medicinal mushroom native to Taiwan. The pharmacological effects of A. cinnamomea have been extensively studied. The aim of the present study was to assess the genotoxic, oral toxic and teratotoxic effects of A. cinnamomea health food product ⿿Leader Deluxe Antrodia cinnamomea (LDAC)⿿⿿ using in vitro and in vivo tests. The Ames test with 5 strains of Salmonella typhimurium showed no signs of increased reverse mutation upon exposure to LDAC up to concentration of 5 mg/plate. Exposure of Chinese Hamster Ovary cells (CHO-K1) to LDAC did not produce an increase in the frequency of chromosomal aberration in vitro. In addition, LDAC treatment did not affect the proportions of immature to total erythrocytes and the number of micronuclei in the immature erythrocytes of ICR mice. Moreover, 14-days single-dose acute toxicity and 90-days repeated oral dose toxicity tests with rats showed that no observable adverse effects were found. Furthermore, after treatment with LDAC (700⿿2800 mg/kg/day) there was no evidence of observable segment II reproductive and developmental toxic effects in pregnant SD rats and their fetuses. These toxicological assessments support the safety of LDAC for human consumption.

Ameliorative Effect of Gallic Acid on Cyclophosphamide-Induced Oxidative Injury and Hepatic Dysfunction in Rats

Cyclophosphamide (CP), a bifunctional alkylating agent used in chemotherapy has been reported to induce organ toxicity mediated by generation of reactive oxygen species and oxidative stress. Gallic acid (GA), a phenolic substance, is a natural antioxidant with proven free radical scavenging activity and offers protection against oxidative damage. This research study was designed to investigate the ameliorative effect of GA against CP-induced toxicity in rats. Twenty-five male Wistar rats (180-200 g) were randomized into five treatment groups: (A) control, (B) CP, 2 mg/kg body weight (b.w.), (C) pre-treatment with GA (20 mg/kg b.w.) for seven days followed by CP (2 mg/kg b.w.) for seven days, (D) co-treatment with GA (20 mg/kg b.w) and CP (2 mg/kg b.w.) for seven days, and (E) GA (20 mg/kg b.w.) for seven days. CP induced marked renal and hepatic damages as plasma levels of urea, creatinine, bilirubin and activities of AST, ALT, ALP and GGT were significantly elevated (p < 0.05) in the CP-treated group relative to control. In addition, hepatic levels of GSH, vitamin C and activities of SOD, catalase and GST significantly reduced in the CP-treated group when compared with control. This was accompanied with a significant increase in hepatic lipid peroxidation. The restoration of the markers of renal and hepatic damages as well as antioxidant indices and lipid peroxidation by pre- and co-treatment with GA clearly shows that GA offers ameliorative effect by scavenging the reactive oxygen species generated by CP. This protective effect may be attributed to the antioxidant property of gllic acid.

Oxidative stress-related liver dysfunction by sodium arsenite: Alleviation by Pistacia lentiscus oil

CONTEXT

Pistacia lentiscus L. (Anacardiaceae) is an evergreen shrub widely distributed throughout the Mediterranean region. Pistacia lentiscus oil (PLo) was particularly known in North African traditional medicine. Thus, people of these regions have used it externally to treat sore throats, burns and wounds, as well as they employed it internally for respiratory allergies. PLo is rich in essential fatty acids, vitamin E and polyphenols. As a very active site of metabolism, liver is reported to be susceptible to arsenic (As) intoxication.

OBJECTIVE

The present study evaluates the protective effect of PLo against sodium arsenite-induced hepatic dysfunction and oxidative stress in experimental Wistar rats.

MATERIALS AND METHODS

Twenty-eight rats were equally divided into four groups; the first served as a control, the remaining groups were respectively treated with PLo (3.3 mL/kg body weight), sodium arsenite (5.55 mg/kg body weight) and a combination of sodium arsenite and PLo. After 21 consecutive days, cellular functions were evaluated by hematological, biochemical and oxidative stress markers.

RESULTS

A significant decrease in the levels of red blood cells, haemoglobin (p ≤ 0.001), hematocrit (p ≤ 0.001), reduced glutathione and metallothionein (p ≤ 0.05) associated with a significant increase of malondialdehyde (p ≤ 0.001) were noticed in the arsenic-exposed group when compared to the control. The As-treated group also exhibited an increase in hepatic antioxidant enzymes namely superoxide dismutase, glutathione peroxidase (p ≤ 0.01) and catalase (p ≤ 0.05). However, the co-administration of PLo has relatively reduced arsenic effect.

CONCLUSION

The results showed that arsenic intoxication disturbed the liver pro-oxidant/antioxidant status. PLo co-administration mitigates arsenic-induced oxidative damage in rat.

Serum alpha tocopherol, vitamin B12, and folate levels in childhood acute lymphoblastic leukemia survivors with and without neuropathy

Various micronutrients are essential for optimal functioning of the peripheral nervous system. Serum vitamin E, vitamin B12, and folic acid were estimated in childhood acute lymphoblastic leukemia survivors aged between 5 and 18 years in first continuous remission within 3 years of completion of vincristine-based chemotherapy with and without electrophysiologically defined neuropathy. A total of 80 children were studied. Neuropathy was seen in 27 (33.75%) children electrophysiologically. None of the children had vitamin E deficiency. However, the alpha tocopherol/(cholesterol + triglyceride) ratio was significantly lower in children with neuropathy (P = .05). The prevalence of folate (P = .48) and vitamin B12 (P = .21) deficiency in children with and without neuropathy was not significantly different. Thus, the prevalence of deficiencies of these micronutrients was not significantly different in childhood acute lymphoblastic leukemia survivors with or without electrophysiologically defined neuropathy.

SIRT1/PGC1α-Dependent Increase in Oxidative Phosphorylation Supports Chemotherapy Resistance of Colon Cancer

PURPOSE

Chemotherapy treatment of metastatic colon cancer ultimately fails due to development of drug resistance. Identification of chemotherapy-induced changes in tumor biology may provide insight into drug resistance mechanisms.

EXPERIMENTAL DESIGN

We studied gene expression differences between groups of liver metastases that were exposed to preoperative chemotherapy or not. Multiple patient-derived colonosphere cultures were used to assess how chemotherapy alters energy metabolism by measuring mitochondrial biomass, oxygen consumption, and lactate production. Genetically manipulated colonosphere-initiated tumors were used to assess how altered energy metabolism affects chemotherapy efficacy.

RESULTS

Gene ontology and pathway enrichment analysis revealed significant upregulation of genes involved in oxidative phosphorylation (OXPHOS) and mitochondrial biogenesis in metastases that were exposed to chemotherapy. This suggested chemotherapy induces a shift in tumor metabolism from glycolysis towards OXPHOS. Indeed, chemotreatment of patient-derived colonosphere cultures resulted in an increase of mitochondrial biomass, increased expression of respiratory chain enzymes, and higher rates of oxygen consumption. This was mediated by the histone deacetylase sirtuin-1 (SIRT1) and its substrate, the transcriptional coactivator PGC1α. Knockdown of SIRT1 or PGC1α prevented chemotherapy-induced OXPHOS and significantly sensitized patient-derived colonospheres as well as tumor xenografts to chemotherapy.

CONCLUSIONS

Chemotherapy of colorectal tumors induces a SIRT1/PGC1α-dependent increase in OXPHOS that promotes tumor survival during treatment. This phenomenon is also observed in chemotherapy-exposed resected liver metastases, strongly suggesting that chemotherapy induces long-lasting changes in tumor metabolism that potentially interfere with drug efficacy. In conclusion, we propose a novel mechanism of chemotherapy resistance that may be clinically relevant and therapeutically exploitable.

Chemoprotective effect of vitamin E in cyclophosphamide-induced hepatotoxicity in rats

Cyclophosphamide (CP) has a range of adverse effects on liver tissue in humans and animals. Administering an antioxidant with CP might reduce such side effects. Therefore, we examined the role of vitamin E in CP-induced liver toxicity in rats. Male Wistar albino rats were divided into four groups, each of seven rats: control, CP only, CP + vitamin E, and vitamin E only groups. The rats were administered treatments intraperitoneally for 7 days. Then the serum malondialdehyde (MDA), alanine aminotransferase (ALT), aspartate transaminase (AST), and lactate dehydrogenase (LDH) levels were determined while the livers were removed, tissue was prepared using routine histological procedures, sections were stained using hematoxylin and eosin, and the terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL) method was applied. Histopathologically, CP caused hydropic degeneration, necrosis, pleomorphism, and mitotic activity. The number of TUNEL-positive cells and the MDA and ALT levels were significantly higher in the CP group. The antioxidant effects of vitamin E significantly decreased the number of TUNEL-positive cells and the ALT and MDA levels, and normalized the liver histopathology. CP induces apoptosis, has toxic effects on liver tissue, and changes the histological structure. The administration of vitamin E prevented the liver tissue damage caused by CP.

Effects of combination therapy of docetaxel with selenium on the human breast cancer cell lines MDA-MB-231 and MCF-7

Purpose

The anticancer property and cytoprotective role of selenium in chemotherapy have been reported. However, the combination effects of selenium on chemotherapy for advanced breast cancer have not yet been clearly defined. The purpose of this study was to investigate the combined effects of selenium on chemotherapy using docetaxel on breast cancer cell lines.

Methods

Under adherent culture conditions, two breast cancer cell lines, MDA-MB-231 and MCF-7, were treated with docetaxel at 500pM and selenium at 100nM, 1µM, or 10µM. Changes in cell growth, cell cycle duration, and degree of apoptosis after 72 hours in each treated group were evaluated.

Results

In the MDA-MB-231 cells, the combination therapy group (docetaxel at 500pM plus selenium at 10µM) showed a significantly decreased percentage of cell growth (15% vs. 28%; P = 0.004), a significantly increased percentage of late apoptosis (63% vs. 26%; P = 0.001), and an increased cell cycle arrest in the G2/M phase (P = 0.001) compared with the solitary docetaxel therapy group. Isobologram analysis demonstrated the synergistic effect of the combination therapy in the MDA-MB-231 cells. However, in the MCF-7 cells, no significant differences in the percentage of cell growth apoptosis, the percentage of apoptosis, and the pattern of cell cycle arrest were noted between the combination therapy groups and the solitary docetaxel therapy group.

Conclusion

Our in vitro study indicated that the combination of selenium with docetaxel inhibits cell proliferation through apoptosis and cell arrest in the G2/M phase in MDA-MB-231 breast cancer cells.

Protective effects of Origanum vulgare ethanol extract against cyclophosphamide-induced liver toxicity in mice

Abstract Context: Despite its wide clinical use, cyclophosphamide (CP), an alkylating chemotherapeutic agent, possesses many adverse effects, including hepatotoxicity. Because Origanum vulgare L. (Lamiaceae) has antioxidative properties, it might protect against above-mentioned damage.

OBJECTIVE

This study evaluated the protective effects of O. vulgare extract on CP-induced liver toxicity.

MATERIALS AND METHODS

Mice were pretreated with aerial parts of O. vulgare ethanolic extract (intraperitoneally) at doses of 50, 100, 200, and 400 mg/kg for 7 consecutive days before the administration of a single 200 mg/kg intraperitoneal dose of CP 1 h after the last injection of O. vulgare. After 24 h, animals were anesthetized, blood samples and hepatic tissues were collected and used for biochemical and histological examination.

RESULTS

Serum levels of hepatic markers were increased after CP treatment but restored in the O. vulgare-pretreated groups. The serum ALT, AST, and ALP of the CP group were 196.49 ± 3.82, 143.78 ± 4.79, and 203.18 ± 3.81 IU/l, respectively. However, pretreatment with 400 mg/kg O. vulgare significantly decreased the serum ALT, AST, and ALP to 52.49 ± 2.18, 44.78 ± 2.06, and 65.62 ± 1.73 IU/l, respectively (p < 0.001). Histological examinations also confirmed the protective effects of O. vulgare against CP-induced liver toxicity.

DISCUSSION AND CONCLUSION

Our results reveal that O. vulgare with high amount of flavonoids and phenolic compounds induces potent hepatoprotective mechanisms against CP. Therefore, O. vulgare might help defend the body against the side effects, particularly hepatic damages induced by chemotherapeutic agents.

Effect of α-tocopheryl succinate on the molecular damage induced by indomethacin in C6 glioma cells

Indomethacin is a member of the non-steroidal anti-inflammatory drug (NSAID) class, which has great potential for use in the treatment of glioma. However, it induces the generation of reactive oxygen species (ROS) and causes molecular damage while inducing its effects. Vitamin E is widely used in the complementary therapy of cancers. The main goal of the present study was to investigate the effects of α-tocopheryl succinate (α-TOS) against the oxidative damage induced by indomethacin in C6 glioma cells. Cells were treated with 10 μM α-TOS alone or in combination with 200 μM indomethacin for two days. The intracellular ROS level, molecular damage as revealed by lipid peroxidation and protein carbonyl formation, and the COX activity in C6 glioma cells were measured. Treatment of the cells with α-TOS and indomethacin, alone or in combination, caused the levels of ROS generation and protein damage to increase, but protected against lipid peroxidation and reduced COX activity.

Tert-butylhydroquinone as a phenolic activator of Nrf2 antagonizes arsenic-induced oxidative cytotoxicity but promotes arsenic methylation and detoxication in human hepatocyte cell line

Oxidative stress plays crucial roles in exerting a variety of damages upon arsenic exposure. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a master transcriptional regulator protecting cells and tissues from oxidative injuries. The objective of this study was to test whether tert-butylhydroquinone (tBHQ), a well-known synthetic Nrf2 inducer, could protect human hepatocytes against arsenic-induced cytotoxicity and oxidative injuries. Our results showed that 5 and 25 μmol/l tBHQ pretreatment suppressed the arsenic-induced hepatocellular cytotoxicity, reactive oxygen species generation, and hepatic lipid peroxidation, while relieved the arsenic-induced disturbances of intracellular glutathione balance. In addition, we also observed that tBHQ treatment promoted the arsenic biomethylation process and upregulated Nrf2-regulated downstream heme oxygenase-1 and NADPH: quinine oxidoreductase 1 mRNA expressions. Collectively, we suspected that Nrf2 signaling pathway may be involved in the protective effects of tBHQ against arsenic invasion in hepatocytes. These data suggest that phenolic Nrf2 inducers, such as tBHQ, represent novel therapeutic or dietary candidates for the population at high risk of arsenic poisoning.

Prophylactic efficacy of melatonin on cyclophosphamide-induced liver toxicity in mice

The current study aimed to evaluate the protective effects of melatonin, a pineal secretory product, against hepatotoxicity induced by cyclophosphamide (CP) in mice. Mice were pretreated with melatonin intraperitoneally for 7 consecutive days before the administration of a single intraperitoneal dose of 200 mg/kg CP. 24 hr after CP administration, the mice were anesthetized, blood was then removed, and serum toxicity enzymes activities were evaluated. After the blood sampling, all animals were killed, livers were then removed, and histological studies were conducted. Serum toxicity marker enzymes were significantly increased after CP treatment but restored in melatonin pretreated groups. In addition, administration of CP induced necrotic hepatocyte with small crushed nuclei, portal space with severe inflammation, and hepatocytes surrounded by lymphocytic infiltration in hepatic tissues. However, melatonin effectively protected against CP-induced histopathological abnormalities in the liver tissues. Our results reveal that melatonin produces a potent hepatoprotective mechanism against CP. Therefore, melatonin could be a potent candidate to use concomitantly as a supplement agent against hepatotoxicity of CP for the patients undergoing chemotherapy.

Amelioration of cisplatin-induced nephrotoxicity by grape seed extract and fish oil is mediated by lowering oxidative stress and DNA damage

Cisplatin (CP) is a chemotherapeutic drug used in treatment of malignancies. However, its clinical utility is limited by nephrotoxicity. The purpose of the present study was to investigate the protective role of grape seed proanthocyanidin extract (GSPE) (100 mg/kg/day) or fish oil (FO) (5 ml/kg/day) against cisplatin induced nephrotoxicity in terms of biochemical parameters, oxidative stress and DNA damage. CP nephrotoxiciy is manifested by increased levels of serum creatinine, urea and uric acid, accompanied by their decrease in urine. Na, K and Ca levels were altered in both serum and urine. In addition, cisplatin caused a decrease in renal GSH, SH-group, SOD, GST, and Na-K-ATPase levels. However the levels of MDA, H2O2 and NO were increased. Also, we assessed the renal genotoxic potential of cisplatin as manifested by an increase in the tail length of DNA, tail intensity (DNA %) and tail moment. On the other hand, administration of GSPE or FO pre-cisplatin treatment ameliorated the current changes in most of the above tested parameters, particularly oxidative stress, endogenous antioxidant defense system and DNA damage indicating their curative effect. Thus, it can be concluded that the consumption of GSPE or FO might be useful for preventing nephrotoxicity caused by cisplatin treatment.

Andrographolide sensitizes the cytotoxicity of human colorectal carcinoma cells toward cisplatin via enhancing apoptosis pathways in vitro and in vivo

Andrographolide (Andro), a diterpenoid lactone isolated from a traditional herbal medicine Andrographis paniculata, has been shown to suppress the growth and invasion of human colorectal carcinoma (CRC) Lovo cells, and trigger apoptosis in vitro. The potential of Andro as a chemotherapeutic agent in CRC was evaluated by investigating its cytotoxic effects as a single agent or in coadministration with cisplatin (CDDP). Andro potentiated the cytotoxic effect of CDDP in Lovo cells through apoptosis. The molecular mechanism for these favorable cellular response was further investigated by analyzing the apoptotic profiles, protein levels, and mRNA expression patterns of several key genes after treatments of Andro or/and CDDP. Molecular results indicated that the effect of Andro alone might be mediated via both intrinsic and extrinsic apoptotic pathways in Lovo cells. The addition of Andro to CDDP induced synergistic apoptosis, which could be corroborated to the changes in protein and mRNA levels of Bax and Bcl-2, and the increased Fas/FasL association in these cells, resulting in increased release of cytochrome c, and activation of caspases. Pretreatment of Nok-1 monoclonal antibody, a Fas signaling inhibitor, or Bax inhibitor peptide V5 repressed the Andro-induced cleavage of procaspase and the sensitization to CDDP-induced apoptosis. Finally, the combination therapy of Andro with CDDP was evidenced by its synergistic inhibition on the growth of Lovo cells in xenograft tumor studies. The results indicate that Andro, in combination with chemotherapeutics, is likely to represent a potential therapeutic strategy for CRC.

The effects of topotecan on lipid peroxidation and antioxidant enzyme levels in rabbit liver tissue

BACKGROUND

To evaluate the possible influence of topotecan therapy on lipid peroxidation and antioxidant enzymes in rabbit liver tissue, the levels of thiobarbituric acid reactive substances (TBARS) and activities of the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were investigated.

METHODS

A total of 24 adult, healthy New Zealand rabbits were divided into three groups (n = 8). Topotecan was administered intravenously via the ear vein for 3 days at 0.25 mg/kg/day for the low-dose group and 0.50 mg/kg/day for the high-dose group; physiological saline was used for the control group. All animals were sacrificed on day 15. Livers were removed and homogenised. The homogenate supernatant was used for measurement of TBARS levels, and SOD, GSH-Px, and CAT enzyme activities (expressed as IU/mg protein).

RESULTS

There were significant differences in the TBARS level and GSH-Px activity between control and the topotecan treatment groups. TBARS level of topotecan treatment groups was higher than control (89% and 126%, respectively, P = 0.001). It was also significantly higher in the high-dose group than the low-dose group (20%; P = 0.011). GSH-Px activity was lower in the low- and high-dose topotecan groups than the control (42% [P = 0.002] and 65% [P = 0.001], respectively). Enzyme activity was lowest in the high-dose group and the difference was also significant when compared with the topotecan groups (40%; P = 0.001). Although there was some decrease in SOD and CAT activities in the topotecan-treated groups, differences from the control group were not significant.

CONCLUSIONS

These findings suggest that topotecan treatment results in an increase in lipid peroxidation and a decrease in antioxidant enzyme activities in healthy liver tissue from rabbits. We believe that the addition of antioxidants to topotecan therapy may reduce the harmful effects of topotecan on liver tissue.

Potential chemoprotective effects of selenium on diazinon-induced DNA damage in rat peripheral blood lymphocyte

The purpose of this study was to investigate the protective effects of selenium (Se) against genotoxicity induced by diazinon (DZN) in rat peripheral blood lymphocytes by micronucleus (MN) test. Animals were concurrently administered intraperitoneally with DZN in proper solvent (20 mg/kg body weight (b.w.)) and Se at three different doses (0.5, 1, and 2 mg/kg b.w.) for 30 consecutive days. The positive control group received DZN at the same dose without Se. After 24 h of last injection, 0.5 ml blood of each rat was received and cultured in culture medium for 44 h. The lymphocyte cultures were mitogenically stimulated with cytochalasin B to allow the evaluation of number of MNs in cytokinesis-blocked binucleated cells. Incubation of lymphocytes with DZN induced additional genotoxicity and is shown by increase in MNs frequency in human lymphocytes. Se at low dose of 0.5 mg/kg had a maximum effect and significantly reduced the MNs frequency in cultured lymphocytes ( p < 0.0001) that reduced the frequency of MN from 12.78 ± 0.24% for DZN group to 4.40 ± 0.36. The present study revealed that Se particularly at low doses has a potent antigenotoxic effect against DZN -induced toxicity in rats, which may be due to the scavenging of free radicals and increased antioxidant status.

Modulation of cyclophosphamide-induced early lung injury by allicin

CONTEXT

Cyclophosphamide (CP) causes lung injury in rats through its ability to generate free radicals with subsequent epithelial and endothelial cell damage.

OBJECTIVE

This study was conducted to assess whether allicin can ameliorate CP-induced early lung injury in rats.

MATERIALS AND METHODS

Male Sprague Dawely rats were divided into four groups. Group I was the control group. Group II received allicin (50 mg/kg/d, p.o.) for 14 consecutive days. Group III was injected once with CP (150 mg/kg, i.p.). Group IV received allicin for seven consecutive days, before and after CP injection (150 mg/kg, i.p.). The parameters of study were serum biomarkers, lung tissue antioxidant profile and histopathological changes in lung tissue.

RESULTS

A single intraperitoneal injection of CP markedly altered the levels of several biomarkers in lung homogenates. Significant increases in lung content of lipid hydroperoxides were seen that paralleled the decreased levels of total reduced glutathione. Superoxide dismutase activity (SOD) was significantly increased. CP increased the level of serum biomarkers; total protein, lactate dehydrogenase (LDH) and tumor necrosis factor-alpha (TNF-α). Pretreatment of rats daily with oral allicin seven days prior to and seven days after CP inject significantly inhibited the development of lung injury, prevented the alterations in lung and serum biomarkers associated with inflammatory reactions, with less lipid peroxidation (LP) and restoration of antioxidants. Moreover, allicin attenuated the secretion of proinflammatory cytokine, TNF-α expression in rat serum. In addition, allicin effectively blunted CP-induced histopathological changes in lung tissue.

DISCUSSION AND CONCLUSION

Our results suggest that allicin is efficient in blunting CP-induced pulmonary damage.

Amelioration of cyclophosphamide-induced hepatotoxicity by the root extract of Decalepis hamiltonii in mice

Hepatoprotective potential of the aqueous extract of the roots of Decalepis hamiltonii (DHA) against cyclophosphamide (CP)-induced oxidative stress has been investigated in mice. Administration of CP (25mg/kg b.w., i.p) for 10 days induced hepatic damage as indicated by the serum marker enzymes aspartate and alanine transaminases (AST, ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH). Parallel to these changes CP induced oxidative stress in the liver as evident from the increased lipid peroxidation (LPO), reactive oxygen species (ROS), depletion of glutathione (GSH), and reduced activities of the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-S-transferase (GST). Treatment with DHA (50 and 100 mg/kg b.w., po) mitigated the CP-induced oxidative stress. Moreover, expression of genes for the antioxidant enzymes, were down-regulated by CP treatment which was reversed by DHA. Our study shows the DHA protected the liver from toxicity induced by CP and therefore, it could be serve as a safe medicinal supplement during cyclophosphamide chemotherapy.

Antigenotoxic effect of lipoic acid against mitomycin-C in human lymphocyte cultures

Antitumor agents are used in therapy against many forms of human cancer. One of these is mitomycin-C (MMC). As with many agents, it can interact with biological molecules and can induce genetic hazards in non-tumor cells. One of the possible approaches to protect DNA from this damage is to supply antioxidants that can remove free radicals produced by antitumor agents. Lipoic acid (LA) is known as one of the most powerful antioxidants. The aim of this study was to investigate antigenotoxic effects of LA against MMC induced chromosomal aberrations (CA), sister chromatid exchanges (SCE) and micronucleus (MN) formation in human lymphocytes. Lymphocytes were treated with 0.2 μg MMC/heparinized mL for 48 h. Three different concentrations (0.5, 1, 2 μg/mL) of LA were used together with MMC in three different applications; 1 h pre-treatment, simultaneous treatment and 1 h post-treatment. A negative, a positive and a solvent control were also included. In all the cultures treated with MMC + LA, the frequency of abnormal cells and CA/cell significantly decreased compared to MMC. Statistically significant reduction was also observed in SCE/cell and MN frequencies in all treatments. These results demonstrated anticlastogenic and antimutagenic effects of LA against MMC induced genotoxicity. LA showed the most efficient effect during 1 h pretreatment. On the other hand, MMC + LA treatments induced significant reduction in mitotic index than that of MMC treatment alone. These results are encouraging that LA can be a possible chemopreventive agent in tumorigenesis in both cancer patients and in health care persons handling anti-cancer drugs.

Epidermal growth factor receptor expression in mice skin upon ultraviolet B exposure - Seborrheic Keratosis as a coincidental and unique finding

Background:

Ultraviolet B (UVB) is the most damaging component of sunlight. It rapidly activates the epidermal growth factor receptor (EGFR) and generates reactive oxygen species (ROS) in excessive quantities that quickly overwhelm tissue antioxidants.

Setting and Design:

To demonstrate the effects of UVB radiation on EGFR expression in mice skin and to evaluate the role of antioxidants in the exposed group.

Materials and Methods:

After obtaining the approval of the ethical committee, forty mice from BALB/c strain were used in this experiment and were allocated into 3 groups; 10 (control group); 15 (exposure group); and 15 (exposed and treated with antioxidants). Antioxidants were administered through subcutaneous injection. Skin biopsies from all groups were stained with EGFR antibodies. Total antioxidant status (TAS) was evaluated in all groups.

Statistical Analysis:

The data obtained were analyzed using ANOVA, Duncan's test, and Pearson's Correlation.

Results:

The highest EGFR expression in exposure group was of score 3⁺ (53%). The highest EGFR expression in treatment group was score 0 (40%). Apoptotic bodies and dermal mast cells increased in exposure group while decreased in treatment group. The mean values for TAS were measured for each group; control group = 1.2 mmol/l; exposure group = 0.87 mmol/l; treatment group =1.3 mmol/l.

Conclusions:

UVB led to Seborrheic Keratosis (SK) in mice through enhancement of EGFR expression. Antioxidants effectively reduced UVB-induced SK, reduced epidermal changes, apoptotic bodies, and decreased dermal mast cells. TAS measurement declined in exposure group, while it was within normal range in most treated cases.

Evaluation of genotoxicity and DNA protective effects of mangiferin, a glucosylxanthone isolated from Mangifera indica L. stem bark extract

Mangiferin is a glucosylxantone isolated from Mangifera indica L. stem bark. Several studies have shown its pharmacological properties which make it a promising candidate for putative therapeutic use. This study was focused to investigate the in vitro genotoxic effects of mangiferin in the Ames test, SOS Chromotest and Comet assay. The genotoxic effects in bone marrow erythrocytes from NMRI mice orally treated with mangiferin (2000 mg/kg) were also evaluated. Additionally, its potential antimutagenic activity against several mutagens in the Ames test and its effects on CYP1A1 activity were assessed. Mangiferin (50-5000 μg/plate) did not increased the frequency of reverse mutations in the Ames test, nor induced primary DNA damage (5-1000 μg/mL) to Escherichia coli PQ37 cells under the SOS Chromotest. It was observed neither single strand breaks nor alkali-labile sites in blood peripheral lymphocytes or hepatocytes after 1h exposition to 10-500 μg/mL of mangiferin under the Comet assay. Furthermore, micronucleus studies showed mangiferin neither induced cytotoxic activity nor increased the frequency of micronucleated/binucleated cells in mice bone marrow. In short, mangiferin did not induce cytotoxic or genotoxic effects but it protect against DNA damage which would be associated with its antioxidant properties and its capacity to inhibit CYP enzymes.

Effect of Buchanania lanzan Spreng. bark extract on cyclophosphamide induced genotoxicity and oxidative stress in mice

OBJECTIVE

To elucidate the effect of ethanolic extract of Buchanania lanzan Spreng. (B. lanan) bark against cyclophosphamide induced genotoxicity and oxidative stress in mice.

METHODS

The prevalence of micronuclei in bone marrow, the extent of lipid peroxidation, reduced glutathione and the status of the antioxidant enzymes, superoxide dismutase and catalase in liver of mice were used as intermediate biomarkers for chemoprotection. Lipid peroxidation and associated compromised antioxidant defenses in cyclophosphamide treated mice were observed in the liver.

RESULTS

Pre-treatment with B. lanzan 250, 500 and 1,000 mg/kg, p.o., daily for 7 days significantly reduced the chromosomal damage and lipid peroxidation with concomitant changes in antioxidants and detoxification systems.

CONCLUSIONS

These results point out the presence of chemopreventive phytoconstituents in the crude extract offering protection against cyclophosphamide induced genotoxicity and oxidative stress in mice.

Effect of vitamin supplementation on cisplatin-induced intestinal epithelial cell apoptosis in Wistar/NIN rats

OBJECTIVE

Chemotherapeutic agents induce small intestinal mucositis that is characterized structurally by crypt loss and villus atrophy and functionally by absorptive and barrier impairments. We studied the effect of selected individual vitamins and multiple-vitamin mixture supplementation in modulating cisplatin-induced intestinal damage and apoptosis.

METHODS

Thirty-six male Wistar/NIN rats 20 wk old and fed the control diet (AIN-93G) were randomly divided into six groups. Five groups were administered cisplatin (2.61 mg/kg of body weight) once a week for 3 wk and were concomitantly provided the control diet or riboflavin, folate, α- tocopherol, or a multiple-vitamin mixture supplemented diet. The sixth group served as a control for cisplatin and received saline as the vehicle. Intestinal epithelial cell apoptosis was monitored by morphometry, M30 staining, DNA fragmentation, and caspase-3 activity. Functional and structural integrities were determined by measuring activities of alkaline phosphatase and lysine ala-dipeptidyl aminopeptidase and the villus height/crypt depth ratio. Oxidative burden was assessed as the formation of thiobarbituric acid-reactive substances and protein carbonyls. Plasma levels of selected vitamins were also measured.

RESULTS

Cisplatin administration significantly increased intestinal apoptosis in the villus and crypt regions that correlated with increased oxidative damage, decreased Bcl-2/Bax, and compromised functional integrity. Riboflavin, folate, and the multiple-vitamin mixture supplementation attenuated the cisplatin-induced increase in apoptotic indices, with a decrease in oxidative burden, increased Bcl-2/Bax, and improved functional and structural integrities. The α-tocopherol supplementation, although effective in attenuating oxidative stress and improving functional integrity, failed to lower the apoptotic indices.

CONCLUSIONS

Riboflavin, folate, and the multiple-vitamin supplementation proved to be more efficacious in attenuating the cisplatin-induced intestinal damage and associated changes in apoptosis.

Modulatory effects of gentisic acid against genotoxicity and hepatotoxicity induced by cyclophosphamide in Swiss albino mice

Objectives

This study evaluated the protective effects of gentisic acid (GA) against genotoxicity and hepatotoxicity induced by cyclophosphamide (CP) in Swiss albino mice.

Methods

Mice were pretreated with GA orally at doses of 50 and 100 mg/kg for 14 consecutive days before the administration of a single intraperitoneal dose of 50 mg/kg CP. The ameliorative effect of GA on genotoxicity was studied using the in-vivo bone marrow micronuclei induction test, DNA integrity and alkaline unwinding assay. The activity of various oxidative stress enzymes were estimated in hepatic tissue.

Key findings

A single intraperitoneal administration of CP in mice increased the malondialdehyde level, depleted the glutathione content and antioxidant enzyme activity (glutathione peroxidase, glutathione reductase, catalase and quinone reductase), and induced DNA strand breaks and micronuclei induction. Oral pretreatment with GA at both doses caused a significant reduction in malondialdehyde and glutathione levels, restoration of antioxidant enzyme activity, reduction in micronuclei formation and DNA fragmentation. Serum toxicity marker enzymes such as aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase were increased after CP treatment but restored in GA pretreated groups.

Conclusion

The results support the protective effect of GA against CP induced genotoxicity and hepatotoxicity.

Effect of n-3 fatty acids on patients with advanced lung cancer: a double-blind, placebo-controlled study

PUFA from fish oil appear to have anti-inflammatory and anti-oxidative effects and improve nutritional status in cancer patients. With this as background, the aim of the present study was to investigate the effect of EPA plus DHA on inflammatory condition, and oxidative and nutritional status in patients with lung cancer. In our multicentre, randomised, double-blind trial, thirty-three patients with a diagnosis of advanced inoperable non-small-cell lung cancer and undergoing chemotherapy were divided into two groups, receiving four capsules/d containing 510 mg of EPA and 340 mg of DHA, or 850 mg of placebo, for 66 d. At the start of chemotherapy (T0), after 8 d (T1), 22 d (T2) and 66 d (T3), biochemical (inflammatory and oxidative status parameters) and anthropometric parameters were measured in both groups. A significant increase of body weight in the n-3 group at T3v. T0 was observed. Concerning inflammation, C-reactive protein and IL-6 levels differed significantly between the n-3 and placebo groups at T3, and progressively decreased during chemotherapy in the n-3 group, evidencing n-3 PUFA anti-inflammatory action. Concerning oxidative status, plasma reactive oxygen species levels increased in the placebo group v. the n-3 group at the later treatment times. Hydroxynonenal levels increased in the placebo group during the study, while they stabilised in the n-3 group. Our data confirm that the continual assumption of EPA plus DHA determined an anti-inflammatory and anti-oxidative action which could be considered a preliminary goal in anti-cachectic therapy.

Protective effect of bixin on cisplatin-induced genotoxicity in PC12 cells

Bixin is the main carotenoid found in annatto seeds (Bixa orellana L.) and is responsible for their reddish-orange color. The antioxidant properties of this compound are associated with its ability to scavenge free radicals, which may reduce damage and protect tissues against toxicity caused by anticancer drugs such as cisplatin. In this study, the genotoxicity and antigenotoxicity of bixin on cisplatin-induced toxicity in PC12 cells was assessed. Cytotoxicity was evaluated using the MTT assay, mutagenicity, genotoxicity, and protective effect of bixin were evaluated using the micronucleus test and comet assay. PC12 cells were treated with bixin (0.05, 0.08, and 0.10μg/mL), cisplatin (0.1μg/mL) or a combination of both bixin and cisplatin. Bixin was neither cytotoxic nor genotoxic compared to the controls. In the combined treatment bixin significantly reduced the percentage of DNA in tail and the frequency of micronuclei induced by cisplatin. This result suggests that bixin can function as a protective agent, reducing cisplatin-induced DNA damage in PC12 cells, and it is possible that this protection could also extend to neuronal cells. Further studies are being conducted to better understand the mechanisms involved in the activity of this protective agent prior to using it therapeutically.

Royal jelly modulates oxidative stress and apoptosis in liver and kidneys of rats treated with cisplatin

Cisplatin (CDDP) is one of the most active cytotoxic agents in the treatment of cancer and has adverse side effects such as nephrotoxicity and hepatotoxicity. The present study was designed to determine the effects of royal jelly (RJ) against oxidative stress caused by CDDP injury of the kidneys and liver, by measuring tissue biochemical and antioxidant parameters and investigating apoptosis immunohistochemically. Twenty-four Sprague Dawley rats were divided into four groups, group C: control group received 0.9% saline; group CDDP: injected i.p. with cisplatin (CDDP, 7 mg kg(-1) body weight i.p., single dose); group RJ: treated for 15 consecutive days by gavage with RJ (300 mg/kg/day); group RJ + CDDP: treated by gavage with RJ 15 days following a single injection of CDDP. Malondialdehyde (MDA) and glutathione (GSH) levels, glutathione S-transferase (GST), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) activities were determined in liver and kidney homogenates, and the liver and kidney were also histologically examined. RJ elicited a significant protective effect towards liver and kidney by decreasing the level of lipid peroxidation (MDA), elevating the level of GSH, and increasing the activities of GST, GSH-Px, and SOD. In the immunohistochemical examinations were observed significantly enhanced apoptotic cell numbers and degenerative changes by cisplatin, but these histological changes were lower in the liver and kidney tissues of RJ + CDDP group. Besides, treatment with RJ lead to an increase in antiapoptotic activity hepatocytes and tubular epithelium. In conclusion, RJ may be used in combination with cisplatin in chemotherapy to improve cisplatin-induced oxidative stress parameters and apoptotic activity.

The use of vitamin E for the prevention of chemotherapy-induced peripheral neuropathy: results of a randomized phase III clinical trial

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) continues to be a substantial problem for many cancer patients. Pursuant to promising appearing pilot data, the current study evaluated the use of vitamin E for the prevention of CIPN.

METHODS

A phase III, randomized, double-blind, placebo-controlled study was conducted in patients undergoing therapy with neurotoxic chemotherapy, utilizing twice daily dosing of vitamin E (400 mg)/placebo. The primary endpoint was the incidence of grade 2+ sensory neuropathy (SN) toxicity (CTCAE v 3.0) in each treatment arm, analyzed by chi-square testing. Planned sample size was 100 patients per arm to provide 80% power to detect a difference in incidence of grade 2+ SN toxicity from 25% in the placebo group to 10% in the vitamin E group.

RESULTS

Two-hundred seven patients were enrolled between December 1, 2006 and December 14, 2007, producing 189 evaluable cases for analysis. Cytotoxic agents included taxanes (109), cisplatin (8), carboplatin (2), oxaliplatin (50), or combination (20). There was no difference in the incidence of grade 2+ SN between the two arms (34%-vitamin E, 29%-placebo; P = 0.43). There were no significant differences between treatment arms for time to onset of neuropathy (P = 0.58), for chemotherapy dose reductions due to neuropathy (P = 0.21), or for secondary endpoints derived from patient-reported neuropathy symptom assessments. The treatment was well tolerated overall.

CONCLUSIONS

Vitamin E did not appear to reduce the incidence of sensory neuropathy in the studied group of patients receiving neurotoxic chemotherapy.

Evaluation of the genotoxic and antigenotoxic effects after acute and subacute treatments with açai pulp (Euterpe oleracea Mart.) on mice using the erythrocytes micronucleus test and the comet assay

Açai, the fruit of a palm native to the Amazonian basin, is widely distributed in northern South America, where it has considerable economic importance. Whereas individual polyphenolics compounds in açai have been extensively evaluated, studies of the intact fruit and its biological properties are lacking. Therefore, the present study was undertaken to investigate the in vivo genotoxicity of açai and its possible antigenotoxicity on doxorubicin (DXR)-induced DNA damage. The açai pulp doses selected were 3.33, 10.0 and 16.67g/kg b.w. administered by gavage alone or prior to DXR (16mg/kg b.w.) administered by intraperitoneal injection. Swiss albino mice were distributed in eight groups for acute treatment with açai pulp (24h) and eight groups for subacute treatment (daily for 14 consecutive days) before euthanasia. The negative control groups were treated in a similar way. The results of chemical analysis suggested the presence of carotenoids, anthocyanins, phenolic, and flavonoids in açai pulp. The endpoints analyzed were micronucleus induction in bone marrow and peripheral blood cells polychromatic erythrocytes, and DNA damage in peripheral blood, liver and kidney cells assessed using the alkaline (pH >13) comet assay. There were no statistically significant differences (p>0.05) between the negative control and the groups treated with the three doses of açai pulp alone in all endpoints analyzed, demonstrating the absence of genotoxic effects. The protective effects of açai pulp were observed in both acute and subacute treatments, when administered prior to DXR. In general, subacute treatment provided greater efficiency in protecting against DXR-induced DNA damage in liver and kidney cells. These protective effects can be explained as the result of the phytochemicals present in açai pulp. These results will be applied to the developmental of food with functional characteristics, as well as to explore the characteristics of açai as a health promoter.