Comparative Genotoxicity and Mutagenicity of Cigarette, Cigarillo, and Shisha Tobacco Products in Epithelial and Cardiac Cells

Genotoxicity of waterpipe smoking in young adults from Sarajevo, Bosnia & Herzegovina

Background

Waterpipe, also known as a hookah or narghile, is a type of tobacco products consumption device. Recently it has been increasingly popular in Bosnia and Herzegovina and the region. Waterpipe consumers are predominantly adolescents and young adults. Many of them believe in slighter harmful effects of waterpipes, compared to cigarettes. We aimed to determine the DNA damage in oral leukocytes and buccal cells of young individuals who have smoked a waterpipe for more than one year.

Methods

The study group consisted of 40 cigarette non-smokers who regularly smoked a waterpipe on average of once per week. As a control, 40 non-smoking individuals were selected to match smokers for age. All participants in the study were healthy male and female adults from Bosnia and Herzegovina, 18-30 years of age. Before sampling, detailed survey and informed consent have been provided by each participant. Comet assay in oral leukocytes and buccal micronucleus cytome (BMCyt) assay in exfoliated buccal cells were applied.

Results

Almost half of waterpipe smokers (WPS) tasted waterpipe at 15-16 years of age. Comet assay analysis showed increased tail intensity, tail length, and tail moment values among WPS compared to non-smokers (NS) (p = 0.0001, p = 0.0067, and p = 0.0001, respectively). Frequencies of the micronucleated (p = 0.0004), binucleated (p = 0.01), karyorrhectic, (p = 0.0036), and pycnotic cells (p = 0.03) were significantly higher in WPS compared to NS group.

Conclusions

Genotoxicity and DNA damage biomarkers were increased in oral leukocytes and exfoliated buccal cells of young waterpipe smokers from Bosnia and Herzegovina, compared to NS group.

Airborne particulate matter (PM10) induces cell invasion through Aryl Hydrocarbon Receptor and Activator Protein 1 (AP-1) pathway deregulation in A549 lung epithelial cells

BACKGROUND

Particulate matter with an aerodynamic size ≤ 10 μm (PM₁₀) is a risk factor for lung cancer development, mainly because some components are highly toxic. Polycyclic aromatic hydrocarbons (PAHs) are present in PM₁₀, such as benzo[a]pyrene (BaP), which is a well-known genotoxic and carcinogenic compound to humans, capable of activating AP-1 transcription factor family genes through the Aryl Hydrocarbon Receptor (AhR). Because effects of BaP include metalloprotease 9 (MMP-9) activation, cell invasion, and other pathways related to carcinogenesis, we aimed to demonstrate that PM₁₀ (10 µg/cm²) exposure induces the activation of AP-1 family members as well as cell invasion in lung epithelial cells, through AhR pathway.

METHODS AND RESULTS

The role of the AhR gene in cells exposed to PM₁₀ (10 µg/cm²) and BaP (1µM) for 48 h was evaluated using AhR-targeted interference siRNA. Then, the AP-1 family members (c-Jun, Jun B, Jun D, Fos B, C-Fos, and Fra-1), the levels/activity of MMP-9, and cell invasion were analyzed. We found that PM₁₀ increased AhR levels and promoted its nuclear localization in A549 treated cells. Also, PM₁₀ and BaP deregulated the activity of AP-1 family members. Moreover, PM₁₀ upregulated the secretion and activity of MMP-9 through AhR, while BaP had no effect. Finally, we found that cell invasion in A549 cells exposed to PM₁₀ and BaP is modulated by AhR.

CONCLUSION

Our results demonstrated that PM₁₀ exposure induces upregulation of the c-Jun, Jun B, and Fra-1 activity, the expression/activity of MMP-9, and the cell invasion in lung epithelial cells, effects mediated through the AhR. Also, the Fos B and C-Fos activity were downregulated. In addition, the effects induced by PM₁₀ exposure were like those induced by BaP, which highlights the potentially toxic effects of the PM₁₀ mixture in lung epithelial cells.

Lipid metabolism disorders contribute to hepatotoxicity of ICR mice induced by nitrosamines exposure

Health risks caused by crucial environmental carcinogens N-nitrosamines triggered ubiquitous attention. As the liver exerted vital function through metabolic process, lipid metabolism disorders have been confirmed as potential drivers for toxicological effects, and the mechanisms of lipid regulation related to hepatotoxicity induced by N-nitrosamines remained largely unclear. In this study, we comprehensively explored the disturbance of hepatic lipid homeostasis in mice induced by nitrosamines. The results implied that nitrosamines exposure induced hepatotoxicity accompanied by liver injury, inflammatory infiltration, and hepatic edema. Lipidomics profiling analysis indicated the decreased levels of phosphatidic acids (PA), phosphatidylcholines (PC), phosphatidylethanolamines (PE), lyso-phosphatidylcholines (LPC), lyso-phosphatidylethanolamines (LPE), diacylglycerols (DAG) and triacylglycerols (TAG), the elevation of ceramides (Cer) and decomposition of free fatty acids (FFA) in high-dose nitrosamines exposure group. Importantly, nitrosamines exposure promoted fatty acid oxidation (FAO) by facilitating fatty acid uptake and decomposition, together with the upregulation of genes associated with FAO accompanied by the activation of inflammatory cytokines TNF-α, IL-1β and NLRP3. Furthermore, fatty acid translocase CD36-mediated fatty acid oxidation was correlated with the enhancement of oxidative stress in the liver caused by nitrosamines exposure. Overall, our results contributed to the new strategies to interpret the early toxic effects of nitrosamines exposure.