Vicia faba root tip micronucleus test on the mutagenicity of water-soluble contents of cigarette smoke

Hydrogen Sulfide Inhibits Bronchial Epithelial Cell Epithelial Mesenchymal Transition Through Regulating Endoplasm Reticulum Stress

Epithelial mesenchymal transition (EMT) is a contributing factor in remodeling events of chronic obstructive pulmonary disease (COPD). Hydrogen sulfide (H₂S) has been implicated in the pathogenesis of COPD, but the effect of H₂S in regulating EMT and the underlying mechanisms is not clear. In this study, we assessed endoplasmic reticulum (ER) stress markers, EMT markers and associated signal molecules in rat lungs, bronchial epithelial cells, and human peripheral lung tissues to investigate the effect of H₂S in regulating EMT and the underlying mechanisms. We found that EMT and ER stress occurred in lung epithelial cells, especially in the bronchial epithelial cells of smokers and COPD patients. In cigarette smoke (CS)-exposed rats, intraperitoneal injection of NaHS significantly alleviated CS-induced lung tissue damage, small airway fibrosis, ER stress, and EMT, while intraperitoneal injection of propargylglycine (cystathionine-gamma-lyase inhibitor) aggravated these effects induced by CS. In the nicotine-exposed 16HBE cells, an appropriate concentration of H₂S donor not only inhibited nicotine-induced ER stress, but also inhibited nicotine-induced enhancement of cell migration ability and EMT. ER stress nonspecific inhibitors taurine and 4-phenyl butyric acid also inhibited nicotine-induced enhancement of cell migration ability and EMT. Both H2S and inositol-requiring enzyme 1 (IRE1) activation inhibitor 4μ8C inhibited nicotine-induced activation of IRE1, Smad2/3 and EMT. These results suggest that H₂S inhibits CS- or nicotine-induced ER stress and EMT in bronchial epithelial cells and alleviates CS-induced lung tissue damage and small airway fibrosis. The IRE1 signal pathway and Smad2/3 may be responsible for the inhibitory effect of H₂S.

Evaluation of the genotoxic potential of reactive black 5 solutions subjected to decolorizing treatments by three fungal strains

The genotoxic potential of solutions of the textile dye "Reactive Black 5" that were subjected to decolorizing treatments with the fungal strains Coriolopsis polyzona MUCL33483, Penicillium sp. MUBA001 and Pycnoporus sp. MUBA002 was tested. The genotoxicity of the solutions was determined by evaluation of micronuclei formation in Vicia faba root cells and calculation of a damage index (MN(ID)). Non-treated Reactive Black 5 solutions (50-1000 ppm) caused a statistically significant increase in micronuclei formation and, by then, in damage index. Solutions of dye treated with C. polyzona MUCL33483 and Pycnoporus sp. MUBA002 showed color loss, probably due to enzymatic breakdown of the colorant, but maintenance or even an increase in genotoxicity. On the other hand, the Penicillium sp. strain MUBA001 caused decolorization of the dye, apparently by adsorption on mycelia, and, for solutions that initially contained 50 ppm of colorant, an elimination of the genotoxicity was observed after three weeks of treatment.

Genotoxicity of tobacco smoke and tobacco smoke condensate: a review

This report reviews the literature on the genotoxicity of mainstream tobacco smoke and cigarette smoke condensate (CSC) published since 1985. CSC is genotoxic in nearly all systems in which it has been tested, with the base/neutral fractions being the most mutagenic. In rodents, cigarette smoke induces sister chromatid exchanges (SCEs) and micronuclei in bone marrow and lung cells. In humans, newborns of smoking mothers have elevated frequencies of HPRT mutants, translocations, and DNA strand breaks. Sperm of smokers have elevated frequencies of aneuploidy, DNA adducts, strand breaks, and oxidative damage. Smoking also produces mutagenic cervical mucus, micronuclei in cervical epithelial cells, and genotoxic amniotic fluid. These data suggest that tobacco smoke may be a human germ-cell mutagen. Tobacco smoke produces mutagenic urine, and it is a human somatic-cell mutagen, producing HPRT mutations, SCEs, microsatellite instability, and DNA damage in a variety of tissues. Of the 11 organ sites at which smoking causes cancer in humans, smoking-associated genotoxic effects have been found in all eight that have been examined thus far: oral/nasal, esophagus, pharynx/larynx, lung, pancreas, myeoloid organs, bladder/ureter, uterine cervix. Lung tumors of smokers contain a high frequency and unique spectrum of TP53 and KRAS mutations, reflective of the PAH (and possibly other) compounds in the smoke. Further studies are needed to clarify the modulation of the genotoxicity of tobacco smoke by various genetic polymorphisms. These data support a model of tobacco smoke carcinogenesis in which the components of tobacco smoke induce mutations that accumulate in a field of tissue that, through selection, drive the carcinogenic process. Most of the data reviewed here are from studies of human smokers. Thus, their relevance to humans cannot be denied, and their explanatory powers not easily dismissed. Tobacco smoke is now the most extreme example of a systemic human mutagen.

Selective reduction of AKR1C2 in prostate cancer and its role in DHT metabolism

BACKGROUND

As androgens play an essential role in prostate cancer, we sought to develop a real-time PCR to characterize mRNA expression profiles of human members of the Aldo-Keto Reductase (AKR) 1C gene family, as well as of 5 alpha-steroid reductase Type II (SRD5A2) in prostate cancer samples. Functional activity and regulation of AKR1C2, a 3 alpha-hydroxysteroid dehydrogenase (HSD) type III, was also assessed in prostate cancer cell lines.

METHODS

Gene specific PCR primers were established and relative gene expression of human AKR1C family members was determined in paired samples of cancerous and surrounding unaffected prostate tissue.

RESULTS

AKR1C2 preferentially reduces DHT to the weak metabolite 5 alpha-androstane-3 alpha,17 beta-diol (3 alpha-diol) without conversion of 3 alpha-diol to DHT in the PC-3 cell line, and its expression was increased by DHT treatment in LNCaP cells. Selectively reduced expression of AKR1C2 mRNA, but not AKR1C1 (97% sequence identity), was found in approximately half of the pairs whereas AKR1C3 relative expression was not significantly altered. No aberrant expression of AKR1C4 expression or significant differences in SRD5A2 gene expression were found.

CONCLUSIONS

AKR1C2 functions as a DHT reductase in prostate-derived cells lines and is regulated by DHT. Additional studies are needed to further define the significance of reduced AKR1C2 expression in prostate cancer and its potential role in modulating local availability of DHT.

Study of external low irradiation dose effects on induction of chromosome aberrations in Pisum sativum root tip meristem

The effects of low doses of ionizing radiation have been a matter of important debate over the last few years. The point of discussion concerns the validity of the linear dose-response extrapolation for low doses, used by international organizations, to establish radio-protection norms. Here, we contributed to this discussion by investigating the induction of chromosome aberrations by low to moderate doses ranging from 0 to 10 Gy in root meristem cells of 6-day-old Pisum plantlets. After acute irradiation of plantlets by a (60)Co source, the percentage of root tip meristem cells displaying chromosome aberrations was estimated immediately after irradiation and after 20 h recovery time. The dose-effect curves show non-linear responses, especially in the low dose range (0- 1 Gy), which is of particular interest. After 20 h of recovery, a steep increase of aberrations was observed for cells exposed to 0.4 Gy, followed by a plateau for doses until 1 Gy. There was an irradiation effect on plant growth during the first and second generations, showing the persistence of cell division anomalies as a long term effect of acute irradiation. This result suggests the induction of a genomic instability. Our results, in agreement with some obtained in animals, show rather non-linear dose-effect responses, with notably higher biological effects of low doses than expected.