Induction of DNA fragmentation, chromosome aberrations and micronuclei by cisplatin in rat bone-marrow cells: protective effect of recombinant human erythropoietin

Cisplatin Reduces the Frequencies of Radiotherapy-Induced Micronuclei in Peripheral Blood Lymphocytes of Patients with Gynaecological Cancer: Possible Implications for the Risk of Second Malignant Neoplasms

Gynaecologic cancers are common among women and treatment includes surgery, radiotherapy or chemotherapy, where the last two methods induce DNA damage in non-targeted cells like peripheral blood lymphocytes (PBL). Damaged normal cells can transform leading to second malignant neoplasms (SMN) but the level of risk and impact of risk modifiers is not well defined. We investigated how radiotherapy alone or in combination with chemotherapy induce DNA damage in PBL of cervix and endometrial cancer patients during therapy. Blood samples were collected from nine endometrial cancer patients (treatment with radiotherapy + chemotherapy-RC) and nine cervical cancer patients (treatment with radiotherapy alone-R) before radiotherapy, 3 weeks after onset of radiotherapy and at the end of radiotherapy. Half of each blood sample was irradiated ex vivo with 2 Gy of gamma radiation in order to check how therapy influenced the sensitivity of PBL to radiation. Analysed endpoints were micronucleus (MN) frequencies, apoptosis frequencies and cell proliferation index. The results were characterised by strong individual variation, especially the MN frequencies and proliferation index. On average, despite higher total dose and larger fields, therapy alone induced the same level of MN in PBL of RC patients as compared to R. This result was accompanied by a higher level of apoptosis and stronger inhibition of cell proliferation in RC patients. The ex vivo dose induced fewer MN, more apoptosis and more strongly inhibited proliferation of PBL of RC as compared to R patients. These results are interpreted as evidence for a sensitizing effect of chemotherapy on radiation cytotoxicity. The possible implications for the risk of second malignant neoplasms are discussed.

Erythropoietin promoter polymorphism is associated with treatment efficacy and severe hematologic toxicity for platinum-based chemotherapy

Background: Erythropoietin (EPO) plays a substantial role in cancer development and probably affects clinical outcomes. A functional polymorphism (rs1617640, G > T) in the promoter region of the EPO increases protein expression. This study investigated the association of EPO rs1617640 with treatment efficacy and severe toxicity in non-small cell lung cancer (NSCLC) patients undergoing platinum-based regimens.Methods: 437 Chinese NSCLC patients treated with platinum-based chemotherapy were recruited. Association between EPO rs1617640 and clinical outcomes was calculated by multivariable logistic regression.Results: The TT genotype of EPO rs1617640 was significantly correlated with a higher response rate to platinum-based treatment than the other genotypes (OR, 0.507; 95% CI: 0.305-0.842; P = 0.009), particularly in elderly patients (>55 years), male gender, smokers, IV stage, cisplatin-based chemotherapies, and platinum-gemcitabine regimen subgroups. As for toxicity, EPO rs1617640 TT genotype demonstrated poorer tolerance to grade 3-4 hematologic toxicity (OR, 1.783; 95% CI: 1.098-2.898; P = 0.019), particularly in subgroups of elderly patients (>55 years), male gender, smokers, IIIA+IIIB stage, and cisplatin-based chemotherapies.Conclusion: Our results demonstrated the role of EPO rs1617640 as a possible predictive marker of treatment efficacy and severe toxicity for platinum-based chemotherapy.

The protective effect of herniarin on genotoxicity and apoptosis induced by cisplatin in bone marrow cells of rats

Herniarin is a member of simple coumarins, which are a group of common secondary metabolites in plants. The aim of the present study was to investigate the effects of herniarin on genotoxicity and apoptosis induced by cisplatin in rat bone marrow cells. The experimental rats were treated with four different doses of herniarin (50, 100, 200, and 400 mg/kg.) for seven consecutive days. The cisplatin (5 mg/kg, i.p.) was injected into mice 1 h after the last oral herniarin administration on the seventh day. The protective effects of herniarin were investigated by hematological test, flow cytometry, micronucleus assay, and reactive oxygen species (ROS) level analysis. Herniarin caused a marked reduction in the frequencies of micronucleated polychromatic erythrocytes (MnPCEs) and micronucleated normochromatic erythrocytes (MnNCEs) 24 h after exposure to cisplatin at doses of 200 and 400 mg/kg. Furthermore, herniarin significantly increased the levels of both red and white blood cells in peripheral blood. Treatment of rats with herniarin before cisplatin, significantly decreased the percentage of apoptotic and necrotic cells and the ROS level in bone marrow cells. This study indicated that herniarin can be introduced as a new chemoprotective agent against cisplatin-induced genotoxicity in the future.

Evaluation of mutagenic activity of platinum complexes in somatic cells of Drosophila melanogaster

Cisplatin, carboplatin, and oxaliplatin are some of the most often used alkylating chemotherapeutic agents. In view of the paucity of data on the genotoxicity of oxaliplatin, this study compares the mutagenic activity of cisplatin (0.006, 0.012, 0.025, 0.05 mM), carboplatin (0.1, 0.2, 0,5, 1.0 mM), and oxaliplatin (0.1, 0.2, 0,5, 1.0 mM) using the somatic mutation and recombination test (SMART) in Drosophila melanogaster. Standard and high-bioactivation crosses of the drosophilid were used, which present basal and high levels of cytochrome P450 (CYP450) metabolization enzymes, respectively. All concentrations of cisplatin and carboplatin induced lesions in genetic material in both crosses, while oxaliplatin was mutagenic only to high bioactivation flies treated with 0.1, 0.5 and 1 mM of the compound. No significant differences were observed between genotoxicity values of cisplatin and carboplatin. However, CYP450 enzymes may have affected the mutagenic action of oxaliplatin. Carboplatin induced mainly mutation events, while cisplatin triggered mostly mutation and recombination events when low and high doses were used. Most events induced by oxaliplatin were generated by somatic recombination. Important differences were observed in genotoxic potential of platinum chemotherapeutic compounds, possibly due to the origin and type of the lesions induced in DNA and the repair mechanisms involved.

Grb2 binds to PTEN and regulates its nuclear translocation to maintain the genomic stability in DNA damage response

Growth factor receptor bound protein 2 (Grb2) is an adaptor protein critical for signal transduction and endocytosis, but its role in DNA damage response (DDR) remains unknown. Here, we report that either knockdown of Grb2 or overexpression of the mutated Grb2 promotes micronuclei formation in response to oxidative stress. Furthermore, Grb2 was demonstrated to interact with phosphatase and tensin homologue (PTEN; a tumor suppressor essential for nuclear stability), and the loss of Grb2 reduced the nuclear-localized PTEN, which was further decreased upon stimulation with hydrogen peroxide (H₂O₂). Overexpression of the T398A-mutated, nuclear-localized PTEN reduced micronuclei frequency in the cells deficient of functional Grb2 via rescuing the H₂O₂-dependent expression of Rad51, a protein essential for the homologous recombination (HR) repair process. Moreover, depletion of Grb2 markedly decreased the expression of Rad51 and its interaction with PTEN. Notably, Rad51 showed a preference to immunoprecipation with the T398A-PTEN mutant, and silencing of Rad51 alone accumulated micronuclei concurring with decreased expression of both Grb2 and PTEN. Our findings indicate that Grb2 interacts with PTEN and Rad51 to regulate genomic stability in DDR by mediating the nuclear translocation of PTEN to affect the expression of Rad51.

Glucosamine Protects Rat Bone Marrow Cells Against Cisplatin-induced Genotoxicity and Cytotoxicity

BACKGROUND AND OBJECTIVE

Glucosamine is a widely prescribed dietary supplement used in the treatment of osteoarthritis. In the present study, the chemoprotectant ability of glucosamine was evaluated against cisplatin-induced genotoxicity and cytotoxicity in rat bone marrow cells.

METHODS

Glucosamine was orally administrated to rats at doses of 75 and 150 mg/kg body weight for seven consecutive days. On the seventh day, the rats were treated with a single injection of cisplatin (5 mg/kg, i.p.) at 1h after the last oral administration. The cisplatin antagonistic potential of glucosamine was assessed by micronucleus assay, Reactive Oxygen Species (ROS) level analysis, hematological analysis, and flow cytometry.

RESULTS

Glucosamine administration to cisplatin-treated rats significantly decreased the frequencies of Micronucleated Polychromatic Erythrocytes (MnPCEs) and Micronucleated Normchromatic Erythrocytes (MnNCEs), and also increased PCE/(PCE+NCE) ratio in bone marrow cells. Furthermore, treatment of rats with glucosamine before cisplatin significantly inhibited apoptosis, necrosis and ROS generation in bone marrow cells, and also increased red blood cells count in peripheral blood.

CONCLUSION

This study shows glucosamine to be a new effective chemoprotector against cisplatin-induced DNA damage and apoptosis in rat bone marrow cells. The results of this study may be helpful in reducing the harmful effects of cisplatin-based chemotherapy in the future.

Metformin attenuates cisplatin-induced genotoxicity and apoptosis in rat bone marrow cells

Metformin is widely used as an oral hypoglycemic drug in the management of type 2 diabetes mellitus. This study evaluated the possible protective effects of metformin against cisplatin-induced genotoxicity and apoptosis in rat bone marrow cells. Two different doses of metformin (50 and 100 mg/kg b.w.) were administered orally to experimental animals for seven consecutive days. On the seventh day, the rats were exposed to cisplatin (5 mg/kg, i.p.) 1 h after the last oral metformin administration. Rats in the control group were treated orally with 10 ml/kg PBS for 7 consecutive days and a single intraperitoneal injection of saline (0.9%) on the 7th day. The antagonistic effects of metformin against cisplatin were evaluated using micronucleus assay, reactive oxygen species (ROS) level analysis, hematological analysis, and flow cytometry. Treatment with 50 and 100 mg/kg metformin before cisplatin injection produced a significant reduction in the frequencies of micronucleated polychromatic erythrocytes (MnPCEs) and micronucleated normochromatic erythrocytes (MnNCEs) 24 h after cisplatin treatment with a corresponding increase in the PCE/(PCE + NCE) ratio. Moreover, metformin markedly elevated the levels of both red and white blood cells in peripheral blood and decreased the percentage of apoptotic cells and the ROS level in bone marrow cells of rats treated with cisplatin. The data suggest that metformin has potential chemoprotective properties in rat bone marrow after cisplatin treatment, which support its candidature as a potential chemoprotective agent for cancer patients undergoing chemotherapy.

Genotoxic and mutagenic studies of teratogens in developing rat and mouse

In this review, genotoxic and mutagenic effects of teratogenic chemical agents in both rat and mouse have been reviewed. Of these chemicals, 97 are drugs and 33 are pesticides or belong to other groups. Large literature searches were conducted to determine the effects of chemicals on chromosome abnormalities, sister chromatid exchanges, and micronucleus formation in experimental animals such as rats and mice. In addition, studies that include unscheduled DNA synthesis, DNA adduct formations, and gene mutations, which help to determine the genotoxicity or mutagenicity of chemicals, have been reviewed. It has been estimated that 46.87% of teratogenic drugs and 48.48% of teratogenic pesticides are positive in all tests. So, all of the teratogens involved in this group have genotoxic and mutagenic effects. On the other hand, 36.45% of the drugs and 21.21% of the pesticides have been found to give negative results in at least one test, with the majority of the tests giving positive results. However, only 4.16% of the drugs and 18.18% of the pesticides were determined to give negative results in the majority of the tests. Among tests with major negative results, 12.50% of the teratogenic drugs and 12.12% of the teratogenic pesticides were negative in all conducted tests.

Assessment of bendamustine-induced genotoxicity in eukaryotic cells

Bendamustine, an anticancer drug with alkylating properties, is widely used to treat hematological malignancies. Since the nitrogen mustard family alkylators induce DNA damages and have been associated with an elevated risk of second malignancy, current study evaluates the cytotoxic, mutagenic, and recombinogenic effects of bendamustine by using, respectively the mitotic index assay, the in vitro mammalian cell micronucleus test (Mnvit) and the chromosome aberration (CA) test in human peripheral lymphocytes, and the in vivo homozygotization assay in Aspergillus nidulans, which detects the loss of heterozygosity (LOH) due to somatic recombination. Bendamustine (6.0 µg/ml, 9.0 µg/ml, and 12.0 µg/ml) induced a statistically significant concentration-related increase in the frequencies of micronuclei and a significant reduction in the cytokinesis block proliferation index (CBPI) rates when compared to negative control. In the CA test, bendamustine significantly increased the frequencies of structural aberrations at the three tested concentrations when compared to the negative control. Aspergillus nidulans diploids, obtained after bendamustine treatment (6.0 µg/ml, 12.0 µg/ml, and 24.0 µg/ml), produced, after haploidization, homozygotization index (HI) rates higher than 2.0 and significantly different from the negative control. Since bendamustine showed genotoxic effects in all tested concentrations, two of them corresponding to the peak plasma concentrations observed in cancer patients treated with bendamustine, data provided in the current research work may be useful to identify the most appropriate dosage regimen to achieve the efficacy and safety of this anticancer medication.

An oxovanadium(IV) complex protects murine bone marrow cells against cisplatin-induced myelotoxicity and DNA damage

Cisplatin (CDDP) is one of the first-line anticancer drugs that has gained widespread use against various forms of human malignancies. But, the therapeutic outcome of CDDP therapy is limited due to its adverse effects including myelotoxicity and DNA damage which may lead to the subsequent risk of developing secondary cancer. Hence, in search of a suitable cytoprotectant, this study investigated the probable protective efficacy of an oxovanadium(IV) complex, namely oxovanadium(IV)-L-cysteine methyl ester complex (VC-IV) against CDDP-induced myelosuppression and genotoxic damage in the bone marrow cells of Swiss albino mice. CDDP was administered intraperitoneally (5 mg/kg b.w.) and VC-IV was administered orally (1 mg/kg b.w.) in concomitant and 7 d pretreatment schedule. Treatment with VC-IV in CDDP-treated mice significantly (p < 0.01) enhanced bone marrow cell proliferation and inhibited cell death in the bone marrow niche indicating improvement of CDDP-induced myelotoxicity. The organovanadium compound also significantly (p < 0.01) reduced the percentage of chromosomal aberrations, the frequency of micronuclei formation, and the extent of DNA damage. The observed chemoprotective effect of VC-IV was attributed to its anti-oxidant efficacy which significantly (p < 0.01) attenuated CDDP-induced generation of free radicals, and restored (p < 0.01) the levels of oxidized and reduced glutathione. Hence, VC-IV may serve as a promising candidate for future development to decrease the deleterious effects of CDDP in the bone marrow cells of cancer patients and associated secondary complications.

Tumor inhibition effects and mechanisms of Angelica sinensis and Sophorae flavescentis ait decoction combined with cisplatin in xenograft mice

BACKGROUND

To investigate tumor inhibition effects and mechanisms of Angelica sinensis and Sophorae flavescentis ait decoction (ASSF) combined with diamine-dichloroplatinum (DDP).

MATERIALS AND METHODS

Bodyweight, tumor inhibition rate and q value were calculated for single ASSF or ASSF combined with DDP on H22 carcinoma xenograft KM mice. Biochemical methods for serum LDH, AST, ALT, and AKP, ELISA method for serum HIF-1α, pathological assessemnt of thymus, immunohistochemistry detection of tumor tissue caspase3 and mutant p53 protein, and qRT-PCR detection of bax/ bcl-2 mRNA were applied.

RESULTS

Compared with DDP control group, the bodyweight increased in ASSF-DDP group (p<0.01). Tumor inhibition rates for DDP, ASSF, ASSF-DDP were 62.7%. 43.7% and 71.0% respectively, with a q value of 0.90. Compared with other groups, thymus of DDP control group had obvious pathological injury (p<0.01), serum LDH, AST, ALT, AKP increased significantly in DDP control group (p<0.01), while serum HIF-1α was increased in the model control group. Compared with this latter, the expression of mutant p53 protein and bcl-2 mRNA were decreased in all treatment groups (p<0.01), but there were no statistical difference between DDP control p and ASSF-DDP groups. The expression of caspase3 protein and bax mRNA was increased in all treatment groups, with statistical differences between the DDP and ASSF-DDP groups (p<0.01).

CONCLUSIONS

ASSF can inhibit bodyweight decrease caused by DDP, can inhibit tumor growth synergistically with DDP mainly through increasing serum HIF-1α and pro-apoptotic molecules such as caspase 3 and bax, rather than through decreasing anti-apoptotic mutant p53 and bcl-2. ASSF can reduce DDP toxicity due to decreasing the release of LDH, AST, ALT, AKP into blood and enhancing thymus protection.

Prevention of myelosuppression and genotoxicity induced by cisplatin in murine bone marrow cells: effect of an organovanadium compound vanadium(III)-l-cysteine

Cisplatin (CDDP) is one of the first-line anticancer drugs indicated for use against various form of human malignancies; but, the therapeutic outcome of CDDP chemotherapy is limited due to the development of myelosuppression and genotoxicity which may lead to secondary cancer. Induction of oxidative stress in normal host cells is thought to be responsible for these adverse effects. Therefore, in search of a potential chemoprotectant, an oraganovanadium compound, viz., vanadium(III)-l-cysteine (VC-III) was evaluated against CDDP-induced clastogenicity and cytotoxicity in bone marrow cells of Swiss albino mice. CDDP was administered intraperitoneally (5mg/kg body weight [b.w.]) and VC-III was given by oral gavage (1mg/kg b.w.) in concomitant and pretreatment schedule. The results showed that VC-III administration significantly (P < 0.001) enhanced cell proliferation and inhibited apoptosis in the bone marrow niche indicating recovery of CDDP-induced myelosuppression. VC-III also significantly (P < 0.001) decreased the percentage of chromosomal aberrations, the frequency of micronuclei formation and the extent of DNA damage. The observed antigenotoxic and cytoprotective effect of VC-III was attributed to its attenuation of free radicals status and restoration of oxidised and reduced glutathione levels. These results suggest that VC-III is a potential candidate for future development as a chemoprotective agent against chemotherapy-associated primary and secondary complications.

Radioprotective effects of Dragon's blood and its extract against gamma irradiation in mouse bone marrow cells

PURPOSE

The radioprotective effects of Dragon's blood (DB) and its extracts (DBE) were investigated using the chromosomal aberrant test, micronucleus and oxidative stress assay for anti-clastogenic and anti-oxidative activity.

MATERIALS AND METHODS

Adult BALB/C mice were exposed to the whole body irradiation with 4 Gy (60)Co γ-rays. DB and DBE were administered orally once a day from 5 days prior to irradiation treatment to 1 day after irradiation. The mice were sacrificed on 24 h after irradiation. The cells of bone marrow were measured by counting different types of chromosomal aberrations and the frequency of micronuclei. Oxidative stress response was carried out by analysis of serum from blood.

RESULTS

DB and DBE significantly decreased the number of bone marrow cells with chromosome aberrations after irradiation with respect to irradiated alone group. The administration of DB and DBE also significantly reduced the frequencies of micronucleated polychromatic erythrocytes (MPCE) and micronucleated normochromatic erythrocytes (MNCE). In addition, DB and DBE markedly increased the activity of antioxidant enzymes and the level of antioxidant molecular. Malondialdehyde (MDA) and nitric oxide (NO) levels in serum were significantly reduced by DB and DBE treatment.

CONCLUSIONS

Our data suggested that DB and DBE have potential radioprotective properties in mouse bone marrow after (60)Co γ-ray exposure, which support their candidature as a potential radioprotective agent.