Cytotoxic evaluation of YSL-109 in a triple negative breast cancer cell line and toxicological evaluations.

Breast cancer (BC) is the leading cause of cancer-related death in women worldwide. Triple negative breast cancer (TNBC) is the most aggressive form of BC being with the worst prognosis and the worst survival rates. There is no specific pharmacological target for the treatment of TNBC; conventional therapy includes the use of non-specific chemotherapy that generally has a poor prognosis. Therefore, the search of effective therapies against to TNBC continues at both preclinical and clinical level. In this sense, the exploration of different pharmacological targets is a continue task that pave the way to epigenetic modulation using novel small molecules. Lately, the inhibition of histone deacetylases (HDACs) has been explored to treat different BC, including TNBC. HDACs remove the acetyl groups from the ɛ-amino lysine resides on histone and non-histone proteins. In particular, the inhibition of HDAC6 has been suggested to be useful for the treatment of TNBC due to it is overexpressed in TNBC. Therefore, in this work, an HDAC6 selective inhibitor, the (S)-4-butyl-N-(1-(hydroxyamino)-3-(naphthalen-1-yl)-1-oxopropan-2-yl) benzamide (YSL-109), was assayed on TNBC cell line (MDA-MB231) showing an antiproliferative activity (IC50 = 50.34 ± 1.11 µM), whereas on fibroblast, it was lesser toxic. After corroborating the in vitro antiproliferative activity of YSL-109 in TNBC, the toxicological profile was explored using combined approach with in silico tools and experimental assays. YSL-109 shows moderate mutagenic activity on TA-98 strain at 30 and 100 µM in the Ames test, whereas YSL-109 did not show in vivo genotoxicity and its oral acute toxicity (LD50) in CD-1 female mice was higher than 2000 mg/kg, which is in agreement with our in silico predictions. According to these results, YSL-109 represents an interesting compound to be explored for the treatment of TNBC under preclinical in vivo models.

Replication stress drives chromosomal instability in fibroblasts of childhood cancer survivors with second primary neoplasms.

New development and optimization of oncologic strategies are steadily increasing the number of long-term cancer survivors being at risk of developing second primary neoplasms (SPNs) as a late consequence of genotoxic cancer therapies with the highest risk among former childhood cancer patients. Since risk factors and predictive biomarkers for therapy-associated SPN remain unknown, we examined the sensitivity to mild replication stress as a driver of genomic instability and carcinogenesis in fibroblasts from 23 long-term survivors of a pediatric first primary neoplasm (FPN), 22 patients with the same FPN and a subsequent SPN, and 22 controls with no neoplasm (NN) using the cytokinesis-block micronucleus (CBMN) assay. Mild replication stress was induced with the DNA-polymerase inhibitor aphidicolin (APH). Fibroblasts from patients with the DNA repair deficiency syndromes Bloom, Seckel, and Fanconi anemia served as positive controls and for validation of the CBMN assay supplemented by analysis of chromosomal aberrations, DNA repair foci (γH2AX/53BP1), and cell cycle regulation. APH treatment resulted in G2/M arrest and underestimation of cytogenetic damage beyond G2, which could be overcome by inhibition of Chk1. Basal micronuclei were significantly increased in DNA repair deficiency syndromes but comparable between NN, FPN, and SPN donors. After APH-induced replication stress, the average yield of micronuclei was significantly elevated in SPN donors compared to FPN (p = 0.013) as well as NN (p = 0.03) donors but substantially lower than for DNA repair deficiency syndromes. Our findings suggest that mild impairment of the response to replication stress induced by genotoxic impacts of DNA-damaging cancer therapies promotes genomic instability in a subset of long-term cancer survivors and may drive the development of an SPN. Our study provides a basis for detailed mechanistic studies as well as predictive bioassays for clinical surveillance, to identify cancer patients at high risk for SPNs at first diagnosis.

Genotoxicity and mutagenicity evaluation of isoquercitrin-γ-cyclodextrin molecular inclusion complex using Ames test and a combined micronucleus and comet assay in rats.

Flavonoids such as quercetin and its glucosides, especially isoquercitrin are well known as anti-inflammatory, anti-allergic, and anti-carcinogenic, etc. The safety of isoquercitrin formulations needs to be established prior to their use in functional food applications. The mutagenicity and genotoxicity of the IQC-γCD inclusion complex were assessed with three standard assays of the bacterial reverse mutation assay (Ames test) and using a combined in-vivo micronucleus and comet assay under the Organisation for Economic Co-operation and Development (OECD) guidelines. In combined rat bone marrow micronucleus and rat liver comet assay performed in male Sprague Dawley (SD) rats, the various doses of IQC-γCD inclusion complex (max. 2000 mg/kg bw) and positive controls ethyl methanesulfonate (EMS) and mitomycin C (MMC), respectively, and negative control (vehicle) were administrated. The results of the Salmonella typhimurium mutagenicity assay (strains TA100, TA1535, WP2uvrA, TA98, and TA1537) after exposure to the IQC-γCD inclusion complex with the absence and presence of the metabolic activation system (S9 fraction from rat liver) revealed a weakly positive response but with no biologically relevant mutagenicity at the conditions examined according to recommended regulatory guidelines. The combined micronucleus and comet assay results reveal that the IQC-γCD inclusion complex did not induce in-vivo genotoxic potential or indication of any oxidative DNA damage in rat liver tissues. Altogether, considering the results of the study, it is unlikely that the consumption of IQC-γCD inclusion complex as food or supplement would present any concern for humans regarding the mutagenicity and genotoxicity.

Comparison of Repair Index in Cigarette and Waterpipe Smokers: A Bio-Monitoring Assessment Using Human Exfoliated Buccal Mucosa Cells.

Background: Repair index (RI) using DNA changes reveals the activity of carcinogenesis. Cigarette and waterpipe smoking are important contributors to oral cavity malignancy. The RI in cigarette and waterpipe smokers has not been compared so far. The aim of this study was to compare the RI in cigarette and waterpipe smokers using the human exfoliated buccal mucosa cells. Methods: The exfoliated buccal mucosa cells of 60 cigarette and waterpipe smokers and 20 nonsmokers were evaluated in a case-control study. The number of micronuclei (MN), broken egg (BE), karyorrhexis (KR), and karyolysis (KL) were counted in 1000 cells from randomly selected fields. The RI = (KL + KR)/(MN + BE) was calculated and compared between subjects and controls. Data were analyzed by one-way analysis of variance (ANOVA), Tukey's Honest Significant Difference (HSD), and Spearman's correlation coefficient test at P < 0.05 probability level. Results: The difference of MN (P < 0.0001), BE (P < 0.0001), KR (P < 0.0001), and KL (P < 0.0001) count was significant between cigarette smokers, waterpipe smokers, and nonsmokers. The RI was significantly different between groups (P = 0.007). The RI was significantly higher in cigarette smokers compared to waterpipe smokers (P = 0.04) and nonsmokers (P = 0.009). Conclusions: The RI was significantly higher in cigarette smokers compared to waterpipe smokers. The finding suggests that due to higher interrupted cellular hemostasis, the risk of carcinoma in waterpipe smokers can be greater than that in cigarette smokers.

Tartrazina induce genotoxicidad en linfocitos de BALB/c Mus musculus / Tartrazine induces genotoxicity in BALB/c Mus musculus lymphocytes

RESUMEN Objetivos. Determinar el efecto genotóxico de la tartrazina en linfocitos de sangre periférica de Mus musculus BALB/c. Materiales y métodos. Se realizó un estudio experimental, a través de cinco grupos, con cinco ratones en cada uno. Se les registró el peso durante 17 semanas y, en la semana 15 se les administró suero fisiológico (control negativo), dicromato de potasio 25 mg/kg de peso corporal (pc) (control positivo) y tartrazina a dosis de 0,75 mg/kg pc, 7,5 mg/kg pc y 75 mg/kg pc, durante siete días, a excepción del control positivo que fue en dosis única. Luego, cada 24 h se obtuvo una muestra de sangre periférica de la cola y se realizó el frotis, secado y coloración. Posteriormente, se realizó el conteo de 1000 linfocitos por muestra de cada ratón, en todos los tratamientos. Resultados. Los tres tratamientos con tartrazina no causaron diferencias significativas en el peso de ratones a la semana 15, pero sí produjeron diferencias significativas en la frecuencia de linfocitos micronucleados, siendo el tratamiento con tartrazina de 75 mg/kg pc el de mayor efecto genotóxico, induciendo un promedio de 1,63 ± 0,08 linfocitos micronucleados, comparado con el control positivo que generó un promedio de 1,42 ± 0,08 linfocitos micronucleados. Conclusiones. La tartrazina produjo un efecto genotóxico, incrementando el número de linfocitos micronucleados, a dosis de 0,75; 7,5 y 75 mg/kg pc y no afecta el peso corporal durante siete días de administración en M. musculus BALB/c.

ABSTRACT Objectives. To determine the genotoxic effect of tartrazine on peripheral blood lymphocytes of BALB/c Mus musculus. Materials and methods. An experimental study was carried out using five groups, with five mice in each group. Their weight was registered for 17 weeks, and at week 15 they were administered physiological saline solution (negative control), potassium dichromate at 25 mg/kg body weight (bw) (positive control) and tartrazine at doses of 0.75 mg/kg bw, 7.5 mg/kg bw and 75 mg/kg bw, for seven days, with the exception of the positive control which was a single dose. Then, every 24 hours, a peripheral blood sample was obtained from the tail, which was then smeared, dried and stained. Subsequently, 1000 lymphocytes were counted for each sample from each mouse, for all treatment groups. Results. The three tartrazine treatments did not cause significant differences in the weight of mice at week 15, but did produce significant differences in the frequency of micronucleated lymphocytes, with the 75 mg/kg bw tartrazine treatment having the greatest genotoxic effect, inducing an average of 1.63 ± 0.08 micronucleated lymphocytes, compared to the positive control which obtained an average of 1.42 ± 0.08 micronucleated lymphocytes. Conclusions. Tartrazine produced a genotoxic effect, increasing the number of micronucleated lymphocytes, at doses of 0.75; 7.5 and 75 mg/kg bw and did not affect body weight during seven days of administration to BALB/c M. musculus.

Mutagenic effect of imidacloprid insecticide: The ameliorative effect of pre and post exposure to olive oil.

Imidacloprid, a systemic chloro-nicotinyl insecticide belong to neonicotinoid insecticides. In this study 120 rats were divided into four groups, the first group used as a control group, the second group was administered imidacloprid at a dose of 22.5 mg/kg b.w. for 4, 8, and 12 weeks. The third group was treated with olive oil (OLO) in a dose of 10 ml/kg body weight for 2 weeks before the oral dose of imidacloprid for 4, 8, and 12 weeks. The fourth group was given OLO in a dose of 10 ml/kg b.w. for 2 weeks after exposure to imidacloprid for 4, 8, and 12 weeks. Bone marrow was collected for micronucleus and chromosomal aberrations assays. The results revealed that imidacloprid induced a mutagenic effect in the 8th and 12th weeks of exposure and OLO decreased the mutagenic effect of imidacloprid in albino rats but not completely revert them to normal. PRACTICAL APPLICATIONS: Using OLO as a protective or therapeutic agent due to it has an ameliorative effect on mutagenicity induced by IMI.

An in vitro investigation into the protective and genotoxic effects of myricetin bulk and nano forms in lymphocytes of MGUS patients and healthy individuals.

The present study investigated the genoprotective and genotoxic effects of myricetin bulk (10 µM) and nano forms (20 µM) in the lymphocytes from pre-cancerous, monoclonal gammopathy of unknown significance (MGUS) patients and healthy individuals using the Comet and micronucleus assays. The study also evaluated the effect of myricetin on P53 expression levels, using the Western blot technique. Results showed that throughout the in-vitro treatment, lymphocytes from the patients group had higher levels of baseline DNA damage compared to the healthy group. Myricetin in both forms induced significant DNA damage, only at higher concentrations (>40 µM). The micronucleus assay showed a significant reduction (P < 0.01) in the frequency of micronuclei in mono-nucleated cells in the patient group treated with the nano form of myricetin at the non-toxic dose of 20 µM. There was a significant increase in both gene and protein P53 levels in lymphocytes isolated from healthy individuals and pre-cancerous patients. These results suggested a protective effect of myricetin and indicated its nutritional supplement potential for protection against cancer development among patients suffering from MGUS.

Radioprotective effect of grape seed extract against gamma irradiation in mouse bone marrow cells.

INTRODUCTION: Ionizing radiations produce free radicals which are often responsible for DNA damage or cell death. Grape seed extract (GSE) is a natural compound having an antioxidant that protects DNA, lipids, and proteins from free radical damages. In this study, radioprotective effect of the GSE has been investigated in mouse bone marrow cells using micronucleus test. MATERIALS AND METHODS: Four groups of mice were investigated in this study: Mice in Group 1 were subjected to injection of distilled water with no irradiation. Mice in Group 2 were exposed to 3 Gy gamma radiation after the injection of distillated water. Mice in Group 3 were injected with 200 mg/kg of the GSE without any irradiation. In another group, mice were exposed to three gray gamma irradiation after the injection of GSE. Animals were killed, and slides were prepared from the bone marrow cells 24 h after irradiation. The slides were stained with May Grunwald-Giemsa method and analyzed microscopically. The frequency of the micronucleated polychromatic erythrocytes (MnPCEs), micronucleated normochromatic erythrocyte (MnNCEs), and polychromatic erythrocyte/polychromatic erythrocyte + normochromatic erythrocyte (PCE/PCE + NCE) ratios was calculated. RESULTS: Injection of GSE significantly decreased the frequency of MnPCEs (P < 0.0001) and MnNCEs (P < 0.05) and increased the ratio of PCE/PCE + NCE (P < 0.0001) compared to the irradiated control group. DISCUSSION AND CONCLUSIONS: GSE could reduce clastogenic and cytotoxic effects of gamma irradiation in mice bone marrow cells; therefore, it can be concluded that the GSE is a herbal compound with radioprotective effects against gamma irradiation. Free radical scavenging and the antioxidant effects of the GSE probably are responsible mechanisms for the GSE radioprotective effects.

Potential anti-genotoxic effect of sodium butyrate to modulate induction of DNA damage by tamoxifen citrate in rat bone marrow cells.

Sodium butyrate (SB) is one of the histone deacetylase inhibitors (HDACi's) that is recently evidenced to have a prooxidant activity and an ability to reduce hydrogen peroxide-induced DNA damage. Since the majority of estrogen receptor positive breast cancer patients are treated with tamoxifen citrate (TC), which exerts well established oxidative and genotoxic effects, thus the basic objective of this study is to determine whether SB could ameliorate or curate tamoxifen citrate-induced oxidative DNA damage and genotoxic effect in vivo through up-regulation of some antioxidant enzymes. The individual and combined effects of SB and TC have been examined on rat bone marrow cells, using Micronucleus assays (MN), Comet assay, DNA fragmentation, expression of some antioxidant genes using Real time-PCR and finally, oxidative stress analysis. SB significantly increased the mitotic activity (P < 0.05), while TC induced marked micronuclei and oxidative DNA damage, in the SB post-treatment group, the combination of SB (300 mg/kg) and TC (40 mg/kg) was able to decrease the induction of MN and oxidative DNA damage through up-regulation of Cat, Sod and Gpx1 genes significantly at (P < 0.05) more efficiently than that in the SB pre-treatment one. Therefore, we postulate that SB can be used therapeutically in combination with TC treatment to modulate TC genotoxic effect by reducing its oxidative stress, and thus being an appropriate agonist agent to combine with TC than each compound alone.