Effects of diethylstilbestrol in human lymphocytes in vitro: A dose and time-dependent study on genotoxic, cytotoxic and apoptotic effects

Most of the biological, chemical or physical agents that cause cell death in certain doses and time of exposure may induce either apoptosis or necrosis. This study explores in what ways the genotoxic, cytotoxic and apoptotic effects of diethylstilbestrol (DES), a chemical agent currently used in the treatment of various types of cancer, on the human lymphocytes depend upon the dose and the exposure time. For this purpose, firstly it aims to determine in what dosages and durations of DES treatment, genotoxicity and cytotoxicity in human lymphocytes occur in vitro. Secondly, it explores the effects of DES on sister-chromatid exchanges (SCEs) and apoptosis and their relation with the nitric oxide (NO) levels. Finally, it investigates whether different dosages of DES and duration of treatment with it are correlated with each other. In so doing, we investigated the relationship among the viability, necrosis and apoptosis rates of human lymphocytes which were treated with five different DES concentrations (1, 5, 10, 15 and 20 μM) for 24, 48 and 72 h, DNA fragmentation analysis of these cells, their mean SCE values and NO levels. We concluded that 5 μM DES at 24 h is the most effective dosage that induces typical features of apoptosis in human lymphocytes. Despite the fact that there are many other studies on the effects of DES on the cancer cells, we thought it might be worth looking into the effects of DES on human lymphocytes in vitro. We meant the present study to contribute to the research done in the field of cancer treatment. (Mol Cell Biochem 276: 45–53, 2005)     

Optical properties of a novel neodymium pentafluoropropionate binuclear complex

A novel neodymium pentafluoropropionate binuclear complex, Nd(C₂F₅COO)₃Dipy (Dipy: 2,2′-dipyridyl), was synthesized and characterized by single-crystal X-ray diffraction. At a concentration of 0.2 M in DMSO-d₆, the Judd-Ofelt parameters (Ω₂, Ω₄, Ω₆) were calculated from the UV-Vis spectrum. According to the small value of Ω₂ and the zero splitting energy of ⁴F/_3/2 level, a symmetric ligand field of the complex was confirmed in DMSO-d₆. Strong emission of the complex in DMSO-d₆ at 1057 nm with a decay time about 1.3 μs were detected when excited at 800 nm pumped by a laser diode. The stimulated emission cross-section of ⁴F_3/2 → ⁴I_11/2 fluorescence transition was 2.36 × 10⁻²⁰ cm² and comparable with some laser glasses, which indicated good radiative properties of this neodymium pentafluoropropionate binuclear complex in liquid matrix.     

The genotoxic and cytotoxic effects of ribavirin in rat bone marrow

The genotoxicity of the 2-furylethylene derivative 1-(5-bromofur-2-yl)-2-nitroethene (2-betaNF) has been evaluated in cultured human peripheral blood lymphocytes at concentrations ranging from 0.5 to 15microg/ml. The frequencies of micronuclei (MN) and sister-chromatid exchanges (SCEs) were used and scored as indicators of genetic damage. To asses the role of the metabolism mediated by the enzymes present in the S9 mix, over the possible genotoxic potential of the test agent, the cultures for MN and SCE demonstrations were treated for 3h in presence and in absence of rat liver microsomal fraction. The results indicate that, under the experimental conditions used, the test agent does not induce significant increases in the frequency of micronucleated cells, irrespective of the presence/absence of metabolic fraction. Nevertheless, a slight increase in the SCE frequency was observed in those cultures treated without the S9 mix; although this slight increase disappeared in the experiments carried out with the microsomal fraction. In addition, cytotoxic/cytostatic effects of (2-betaNF) were observed mainly in the cultures treated without the S9 fraction.     

The genotoxic and cytotoxic effects of ribavirin in rat bone marrow

The genotoxic and cytotoxic effects of the antiviral drug, ribavirin, was studied in rat bone marrow by employing the micronucleus assay. Ribavirin in doses of 10, 15, 20, 30, 50, 75, 100 and 200 mg/kg, and cyclophosphamide (CP) 40 mg/kg (only for sex-difference study) were injected intraperitoneally. Bone marrow was collected at 24 h and 48 h following the injection. To evaluate the recovery, the bone marrow was also sampled at 72 h from 20, 100 and 200 mg/kg treated rats. The micronucleus assay was conducted according to the standard procedure. Ribavirin elevated the incidence of micronuclei (except 10 mg/kg) in erythrocytes (P<0.01). The micronucleated polychromatic erythrocytes showed the initial steep increase at 15 and 20 mg/kg dose level, then with the gradual increase, possibly due to the limited metabolism and action of higher doses. The incidence of micronucleated normochromatic erythrocytes was not dose dependent. The effect was more at 48 h than 24 h due to prolonged toxicity of the drug or its metabolites, and by 72 h, recovery was observed eventhough the genotoxicity was significant. The PCE% decreased as the dose was increased up to 75 mg/kg, then without much difference between two higher doses. Only 100 mg/kg ribavirin and CP showed more toxicity on male rats. Cytotoxicity was seen due to hindered erythropoiesis or cell destruction. Our findings suggest that ribavirin is genotoxic and cytotoxic agent for rat bone marrow.     

The effect of tamoxifen and raloxifene on estrogen metabolism and endometrial cancer risk

Selective estrogen receptor modulators (SERMs) demonstrate differential endometrial cancer (EC) risk. While tamoxifen (TAM) use increases the risk of endometrial hyperplasia and malignancy, raloxifene (RAL) has neutral effects on the uterus. How TAM increases the risk of EC and why TAM and RAL differentially modulate the risk for EC, however, remain elusive. Here, we tested the hypothesis that TAM increases the risk for EC, at least in part, by enhancing the local estrogen biosynthesis and directing estrogen metabolism towards the formation of genotoxic and hormonally active estrogen metabolites. In addition, the differential effects of TAM and RAL in EC risk are attributed to their differential effect on estrogen metabolism/metabolites. The endometrial cancer cell line (Ishikawa cells) and the nonmalignant immortalized human endometrial glandular cell line (EM1) were used for the study. The profile of estrogen/estrogen metabolites (EM), depurinating estrogen-DNA adducts, and the expression of estrogen-metabolizing enzymes in cells treated with 17β-estradiol (E2) alone or in combination with TAM or RAL were investigated using high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS(2)), ultraperformance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS), and Western blot analysis, respectively. TAM significantly increased the total EM and enhanced the formation of hormonally active and carcinogenic estrogen metabolites, 4-hydroxestrone (4-OHE1) and 16α-hydroxyestrone, with concomitant reduction in the formation of antiestrogenic and anticarcinogenic 2-hydroxyestradiol and 2-methoxyestradiol. Furthermore, TAM increased the formation of depurinating estrogen-DNA adducts 4-OHE1 [2]-1-N7Guanine and 4-OHE1 [2]-1-N3 Adenine. TAM-induced alteration in EM and depurinating DNA adduct formation is associated with altered expression of estrogen metabolizing enzymes CYP1A1, CYP1B1, COMT, NQO1, and SF-1 as revealed by Western blot analysis. In contrast to TAM, RAL has minimal effect on EM, estrogen-DNA adduct formation, or estrogen-metabolizing enzymes expression. These data show that TAM perturbs the balance of estrogen-metabolizing enzymes and alters the disposition of estrogen metabolites, which can explain, at least in part, the mechanism for TAM-induced EC. These results also implicate the differential effect of TAM and RAL on estrogen metabolism/metabolites as a potential mechanism for their disparate effects on the endometrium.     

The genotoxic effect of beta-propiolactone on mammalian oocytes

beta-Propiolactone (beta PL) has been tested on preimplantation mouse embryos for possible genotoxic effects. Tests were performed at different stages of meiosis (late prophase I, diakinesis/metaphase I, anaphase I, telophase I/prophase II and metaphase II) by injecting females at various times after the induction of superovulation. Male and female derived chromosome complements from first-cleavage embryos were analysed before syngamy for cytogenetic abnormalities. A higher proportion of diploid oocytes, produced by the non-extrusion of the first or second polar body, was found after fertilization when the compound was administered immediately before metaphase I or II. No obvious effect was detected at any other time of beta PL exposure. Based on these results, several possible modes of action for beta PL are postulated.     

Synthesis, spectral and structural studies of novel binuclear Ni(II) complex of salicylaldehyde 3-azacyclothiosemicarbazone

A novel binuclear Ni(II) complex of salicylaldehyde 3-azacyclothiosemicarbazone (H₂L) has been synthesized and characterized by elemental analysis, IR and UV-Vis spectroscopy. The single crystal X-ray structure of the complex shows that bridging occurs through thiolato sulfur and phenolic oxygen atoms. Nickel centers in the complex have square planar and octahedral geometries.     

The genotoxic and cytotoxic effects of nicotine in the mouse bone marrow

The objective of the present study was to investigate the potential of nicotine to induce micronucleated polychromatic erythrocytes (MNPCE) in bone marrow of male and female mice. Cyclophosphamide at 40mg/kg was used as positive control clastogen. Single doses of 4, 8 or 16mg/kg nicotine were given via oral intubation and bone marrow was sampled at 18, 24, 30, 36 and 48h after treatment. Cyclophosphamide yielded the expected positive results. Despite the evident signs of acute toxicity shown by the animals, mainly at the 8 and 16mg/kg doses of nicotine, and the reduction in the % PCE, the results show that the MNPCE frequency in male and female mice was not affected by treatment with any of the selected doses of nicotine, in either of the sampling times 18 or 24h. However, at 30 and 36h after treatment, the MNPCE showed significant increases in both genders after doses of 8 and 16mg/kg. A sex-dependent response was recorded, with males having more MNPCE than females after treatment with 8 or 16mg/kg nicotine and sampling at 30h. However, at 36h more MNPCE were induced in females than in males, suggesting different degrees of dose interaction in the sexes under the conditions of the assay. The response was directly correlated with bone-marrow toxicity, as greater bone-marrow suppression was noted in females than in males when 36h samples were examined. By 48h recovery was observed even though the cytotoxicity was high. These findings suggest that nicotine at high doses and after prolonged time intervals is genotoxic and cytotoxic for mouse bone marrow.     

The genotoxic effect of gunshot wounds

Evidence for alterations in chromosomes of experimental animals (rats) and humans after gunshot wounds is presented. The rate of chromatid exchanges induced by gunshot wounds in humans depend on the saturation of body tissues with ascorbic acid. It is assumed that free-radical processes underlie the deleterious effect of gunshot wounds on chromosomes.     

A novel binuclear palladium complex with benzothiazole-2-thiolate: synthesis, crystal structure and interaction with DNA

The novel Pd(II) complex, [Pd(2)(micro-bzta)(4)].1.5DMSO (where bzta=benzothiazole-2-thiolate) has been synthesized and structurally characterized by element analysis, IR and single-crystal X-ray diffractometry. In the binuclear complex, two palladium(II) are bridged by four deprotonated benzothiazole-2-thialate in a head to tail disposition and the distance of the two Pd(II) is 2.747 A. Three-dimensional structure of the complex was constructed though S...S (3.339 A) weak interaction and pi...pi stack. The binding of the title complex with fish sperm DNA (FS-DNA) has been investigated by absorption and fluorescence spectra. The results indicate that the complex bind to FS-DNA in an intercalative mode and the intrinsic binding constant K of the title complex with FS-DNA is about 1.2 x 10(4)M(-1). Gel electrophoresis assay demonstrates the ability of the complex to cleave the pUC19 plasmid DNA.     

Induction of genotoxic and cytotoxic damage by aclarubicin, a dual topoisomerase inhibitor

The anthracycline aclarubicin (ACLA) is an intercalative antibiotic and antineoplastic agent that efficiently binds to DNA, leading to a secondary inhibition of the catalytic activity of topoisomerase II (topo II) on DNA. Besides this activity, ACLA has been reported to exert a concomitant poisoning effect on topo I, in a fashion similar to that of the antitumor drug camptothecin and its derivatives. As a consequence of this dual (topo II catalytic inhibiting/topo I poisoning) activity of ACLA, the picture is somewhat confusing with regards to DNA damage and cytotoxicity. We studied the capacity of ACLA to induce catalytic inhibition of topo II as well as cytotoxic effects and DNA damage in cultured Chinese hamster V79 cells and their radiosensitive counterparts irs-2. The ultimate purpose was to find out whether differences could be observed between the two cell lines in their response to ACLA, as has been widely reported for radiosensitive cells treated with topo poisons. Our results seem to agree with the view that the radiosensitive irs-2 cells appear as hypersensitive ACLA as compared with radiation repair-proficient V79 cells. The recovery after ACLA treatment was also followed-up, and the irs-2 mutant was found to be less proficient than V79 to repair DNA strand breaks induced by ACLA.     

The apoptotic effect of intercalating agents on HPV-negative cervical cancer C-33A cells

Summary. Cervical cancer is one of the leading causes of female cancer death worldwide with about 500,000 deaths per year. Both mitomycin C and cisplatin are alkylating agents, which bind and intercalate DNA, and thus used as anti-cancer drugs. In these studies, we focused on investigating the apoptotic effects of intercalating agents on HPV-negative cervical cancer C-33A cells. Accordingly, C-33A cells were treated with carboplatin, mitomycin C or cisplatin. Cell cycle analysis revealed that treatment with mitomycin C and cisplatin but not with carboplatin resulted in apoptosis. Both mitomycin C and cisplatin induced apoptosis in C-33A cells via caspase-8 and -3 processing in a Fas/FasL-dependent manner and also suppressed IL-18 expression, while they down-regulated IκB expression and up-regulated p65 expression. These results suggest that both mitomycin C and cisplatin induce apoptosis, not only via the caspase-8 and -3 dependent Fas/FasL pathway, but also via the regulation of NF-κB activity and IL-18 expression in HPV-negative cervical cancer C-33A cells.     

Biological evaluation of a cytotoxic 2-substituted benzimidazole copper(II) complex: DNA damage,antiproliferation and apoptotic induction activity in human cervical cancer cells

Exploring novel chemotherapeutic agents is a great challenge in cancer medicine. To that end, 2-substituted benzimidazole copper(II) complex, [Cu(BMA)Cl₂]·(CH₃OH) (1) [BMA = N,N′-bis(benzimidazol-2-yl-methyl)amine], was synthesized and its cytotoxicity was characterized. The interaction between complex 1 and calf thymus DNA was detected by spectroscopy methods. The binding constant (K _b = 1.24 × 10⁴ M^?1) and the apparent binding constant (K _app = 6.67 × 10⁶ M^?1) of 1 indicated its moderate DNA affinity. Complex 1 induced single strand breaks of pUC19 plasmid DNA in the presence of H₂O₂ through an oxidative pathway. Cytotoxicity studies proved that complex 1 could inhibit the proliferation of human cervical carcinoma cell line HeLa in both time- and dose-dependent manners. The results of nuclei staining by Hoechst 33342 and alkaline single-cell gel electrophoresis proved that complex 1 caused cellular DNA damage in HeLa cells. Furthermore, treatment of HeLa cells with 1 resulted in S-phase arrest, loss of mitochondrial potential, and up-regulation of caspase-3 and -9 in HeLa cells, suggesting that complex 1 was capable of inducing apoptosis in cancer cells through the intrinsic mitochondrial pathway.     

Gamma-decanolactone effect on behavioral and genotoxic parameters

Gamma-decanolactone is a monoterpene compound, which is shown to be active in some animal models. The psychopharmacological evaluation of this compound in mice has revealed that it has a dose-dependent effect on the central nervous system, including hypnotic, anticonvulsant and hypothermic activities. The aim of the present study was to evaluate the effect of gamma-decanolactone at 0.1 and 0.3 g/kg on behavior parameters related to plus-maze, open field and forced swim tests. In addition, we investigated its genotoxic activity. Gamma-decanolactone at the dose of 0.3 g/kg, but not 0.1 g/kg, decreased the number of crossings and rearings and there were no significant differences among groups regarding the latency to start locomotion in open field. A single i.p. administration of gamma-decanolactone, at the higher, but not at lower dose used, was able to increase the exploratory activity in the test session (24 h after training), as assessed by the number of rearings performed in open field, and induced DNA damage on brain tissue as measured in comet assay, suggesting an impairment of nonassociative, nonaversive learning and a genotoxic effect on CNS. Gamma-decanolactone did not change the behavior of animals in plus-maze and forced swim tests, suggesting this compound shows no anxiolytic or antidepressant activity.     

The cytogenetic evaluation of in vivo genotoxic and cytotoxic activity using rodent somatic cells

With the growing realization that in vitro short-term tests for genotoxicity can never fully mimic in vivo conditions, the evaluation of genotoxic damage in somatic cells of rodents has played an increasingly important role in assessing the carcinogenic potential of suspect compounds. Among the various genotoxic endpoints assessed in in vivo somatic cell assays, cytogenetic endpoints (e.g., chromosomal aberrations, micronuclei, sister chromatid exchanges) continue to be used most frequently. The purpose of this paper is to demonstrate the utility of evaluating different cytogenetic endpoints in the same animal, using as examples studies to evaluate the in vivo genotoxic potential of benzene, of methylisocyanate, and of butadiene, chloroprene and isoprene.Abbreviations CA chromosomal aberrations - MI mitotic index - MIC methylisocyanate - MN-NCE micronucleated monochromatic erythrocytes - MN-PCE micronucleated polychromatic erythrocytes - SCE sister chromatid exchange     

The cytotoxic,neurotoxic, apoptotic and antiproliferative activities of extracts of some marine algae on the MCF-7 cell line

We investigated the cytotoxic, neurotoxic, apoptotic and antiproliferative effects of extracts from Petalonia fascia, Jania longifurca and Halimeda tuna on the MCF-7 breast cancer cell line. J. longifurca extracts were more toxic than those of P. fascia and H. tuna. The algal extracts showed significant toxic effects at different dilutions. The toxic effects were due to increased oxidative stress and resulted in apoptosis. Algal toxicity may exert negative effects through the food chain or by direct interaction. Algal toxicity also has potential for cancer therapy. The toxic effects that we observed may be especially important for therapy for breast tumors.     

The genotoxic effect of the new acaricide etoxazole

Etoxazole is a member of the diphenyl oxazoline class of insecticide was newly developed for use on pome fruits, cotton and strawberries as a acaricide. In the present study, genotoxic effects of acaricide etoxazole (ETX) (miticide/ovicide) were investigated using chromosome aberration (CA) test, sister chromatid exchange (SCE) test and micronucleus test in human lymphocytes. ETX induced the CAs at all concentrations (5, 10 and 20 microg/ml) for 24 h and also induced the CA at the highest concentration (20 microg/ml) for 48 h only. The inducing the CAs for 48 hours treatment period was dose-dependent. Besides, it induced the SCE at all concentrations and treatment periods in a dose-dependent manner as well. Although, ETX decreased the mitotic index (MI) at all concentration and treatment periods dose-dependently, while it did not decrease the replication index (RI) when compared to the negative and solvent controls. In addition, ETX induced the micronucleus at all concentrations except 5 microg/ml for 48 h. This inducing was in a dose-dependent manner as well. In conclusion, it can be concluded that ETX has a potential genotoxic effects in cultured human peripheral lymphocytes.     

Synthesis and biological evaluation of novel cytotoxic phospholipids for prostate cancer

We describe herein synthesis, SAR, and biological evaluation of a novel series of cytotoxic serine amide phosphates (SAPs) for prostate cancer. These compounds were tested for their cytotoxicity in five human prostate cancer cell lines (DU-145, PC-3, LNCaP, PPC-1, and TSU), and in CHO and RH7777 cells (negative controls). Comparison of anticancer effects of these compounds with a standard chemotherapeutic agent 5-fluorouracil shows that they are very effective in killing prostate cancer cells with low micromolar cytotoxicity and provide us a new lead for the development of drugs for prostate cancer.