Evaluation of miR-9 and miR-143 expression in urine specimens of sulfur mustard exposed patients

Epigenetic alterations induced by genotoxic occupational and environmental human chemical carcinogens: An update of a systematic literature review

Epigenetic alterations, such as changes in DNA methylation, histones/chromatin structure, nucleosome positioning, and expression of non-coding RNAs, are recognized among key characteristics of carcinogens; they may occur independently or concomitantly with genotoxic effects. While data on genotoxicity are collected through standardized guideline tests, data collected on epigenetic effects is far less uniform. In 2016, we conducted a systematic review of published studies of genotoxic carcinogens that reported epigenetic endpoints to better understand the evidence for epigenetic alterations of human carcinogens, and the potential association with genotoxic endpoints. Since then, the number of studies of epigenetic effects of chemicals has nearly doubled. This review stands as an update on epigenetic alterations induced by occupational and environmental human carcinogens that were previously and recently classified as Group 1 by the International Agency for Research on Cancer. We found that the evidence of epigenetic effects remains uneven across agents. Studies of DNA methylation are most abundant, while reports concerning effects on non-coding RNA have increased over the past 5 years. By contrast, mechanistic toxicology studies of histone modifications and chromatin state alterations remain few. We found that most publications of epigenetic effects of carcinogens were studies in exposed humans or human cells. Studies in rodents represent the second most common species used for epigenetic studies in toxicology, in vivo exposures being the most predominant. Future studies should incorporate dose- and time-dependent study designs and also investigate the persistence of effects following cessation of exposure, considering the dynamic nature of most epigenetic alterations.

Toxicology of Blister Agents: Is Melatonin a Potential Therapeutic Option?

Blister or vesicant chemical warfare agents (CWAs) have been widely used in different military conflicts, including World War I and the Iran-Iraq War. However, their mechanism of action is not fully understood. Sulfur and nitrogen mustard exert toxic effects not only through the alkylation of thiol-bearing macromolecules, such as DNA and proteins, but also produce free radicals that can develop direct toxic effects in target organs such as the eyes, skin, and respiratory system. The lack of effective treatments against vesicant CWAs-induced injury makes us consider, in this complex scenario, the use and development of melatonin-based therapeutic strategies. This multifunctional indoleamine could facilitate neutralization of the oxidative stress, modulate the inflammatory response, and prevent the DNA damage, as well as the long-term health consequences mediated by vesicant CWAs-induced epigenetic mechanisms. In this context, it would be essential to develop new galenic formulations for the use of orally and/or topically applied melatonin for the prophylaxis against vesicant CWAs, as well as the development of post-exposure treatments in the near future.

Deciphering the role of microRNAs in mustard gas-induced toxicity

Mustard gas (sulfur mustard, SM), a highly vesicating chemical warfare agent, was first deployed in warfare in 1917 and recently during the Iraq-Iran war (1980s) and Syrian conflicts (2000s); however, the threat of exposure from stockpiles and old artillery shells still looms large. Whereas research has been long ongoing on SM-induced toxicity, delineating the precise molecular pathways is still an ongoing area of investigation; thus, it is important to attempt novel approaches to decipher these mechanisms and develop a detailed network of pathways associated with SM-induced toxicity. One such avenue is exploring the role of microRNAs (miRNAs) in SM-induced toxicity. Recent research on the regulatory role of miRNAs provides important results to fill in the gaps in SM toxicity-associated mechanisms. In addition, differentially expressed miRNAs can also be used as diagnostic markers to determine the extent of toxicity in exposed individuals. Thus, in our review, we have summarized the studies conducted so far in cellular and animal models, including human subjects, on the expression profiles and roles of miRNAs in SM- and/or SM analog-induced toxicity. Further detailed research in this area will guide us in devising preventive strategies, diagnostic tools, and therapeutic interventions against SM-induced toxicity.

Urinary MicroRNAs as Emerging Class of Noninvasive Biomarkers

MicroRNAs (miRNAs) are endogenous noncoding RNAs, which regulate gene expression on the post-transcriptional level. Since miRNAs are involved in the regulation of apoptosis, cellular proliferation, differentiation, and other important cellular processes, their deregulation is important for the development of a wide range of diseases including cancer. Apart from tissue, specific disease-related miRNA signatures can be found in body fluids as well. Especially for urologic diseases or injuries, urine miRNAs represent a promising group of biomarkers. Despite a large number of studies describing the importance of urinary miRNAs, there is a lack of recommendations for urine management and subsequent miRNA analysis. Thus, in this chapter, we aim to describe the origin and functions of urinary miRNAs and discuss the technical aspects of their detection including the pre-analytical phase principles and new directions in quantification, which could forward urine miRNA into clinical practice.

Study of miR-143 expression in stomach cancer

The present study was planned to investigate miR-143 expression during stomach cancer. The study explored the relationship between miR-143 expression and clinicopathological characteristics including proliferation, migration and apoptosis of stomach cancer cells. Sixty-three samples from each of stomach cancer tissue and surrounding tissue were obtained. Total RNA was extracted. The expression levels of miR-143 from stomach cancer tissue as well as from surrounding tissue were measured by semi-quantitative PCR. The effects of miR-143 overexpression on the migration of stomach cancer cells were examined by Transwell assay. The effects of miR-143 overexpression on the apoptosis of stomach cancer cells were examined by flow cytometer. The expression level of miR-143 was significantly decreased in stomach cancer tissues in comparison to surrounding tissues (P<0.01). Moreover, the expression of miR-143 related well with the tumor size, TNM stage, lymphatic metastasis and relapse (P<0.01). On the other hand, stomach cancer cell line with overexpression of miR-143, showed significant decline in proliferation rate and migration rate comparison to control cells (P<0.01). However, it showed significant higher in apoptosis rate (P<0.01). The present study concluded that expression of miR-143 is low during stomach cancer. Further, higher expression levels of miR-143 have the ability to decline proliferation and migration of stomach cancer cells. In this manner, the expression level of miR-143 could be used as an important factor to determine the severity of stomach cancer.

The mechanism of miR-143 inducing apoptosis of liver carcinoma cells through regulation of the NF-κB pathway

Primary hepatic carcinoma is a common malignant tumor with poor treatment efficacy. The effect and mechanism of miR-143 in apoptosis of liver carcinoma cells were investigated in the present study. In vitro transfection of liver carcinoma SMMC-7721 cells was performed using artificially synthesized miR-143 mimics. The proliferation of liver carcinoma cells that were treated was detected by MTT assay. Liver carcinoma cells were then stained using the Annexin V-FITC/PI method, and the apoptosis of stained liver carcinoma cells was measured using a flow cytometer. The relative mRNA expression of NF-κB p65 in the intervention and control groups was assayed using reverse transcription-quantitative polymerase chain reaction, and the protein expression of NF-κB p65 was detected using western blot analysis. The results showed that, in the intervention group, the proliferation rate of cells transfected using miR-143 mimics was significantly lower than that in the control group, the number of apoptotic SMMC-7721 cells in the intervention group increased, and the protein expression of NF-κB p65 was decreased. Thus, miR-143 may downregulate the protein expression of NF-κB p65, thereby triggering the NF-κB signaling transduction pathway inducing apoptosis of liver carcinoma cells.