Electronic cigarettes induce DNA strand breaks and cell death independently of nicotine in cell lines

Abstract

Objectives Evaluate the cytotoxicity and genotoxicity of short- and long-term e-cigarette vapor exposure on a panel of normal epithelial and head and neck squamous cell carcinoma (HNSCC) cell lines. Materials and Methods HaCaT, UMSCC10B, and HN30 were treated with nicotine-containing and nicotine-free vapor extract from two popular e-cigarette brands for periods ranging from 48 hours to 8 weeks. Cytotoxicity was assessed using Annexin V flow cytometric analysis, trypan blue exclusion, and clonogenic assays. Genotoxicity in the form of DNA strand breaks was quantified using the neutral comet assay and γ-H2AX immunostaining. Results E-cigarette-exposed cells showed significantly reduced cell viability and clonogenic survival, along with increased rates of apoptosis and necrosis, regardless of e-cigarette vapor nicotine content. They also exhibited significantly increased comet tail length and accumulation of γ-H2AX foci, demonstrating increased DNA strand breaks. Conclusion E-cigarette vapor, both with and without nicotine, is cytotoxic to epithelial cell lines and is a DNA strand break-inducing agent. Further assessment of the potential carcinogenic effects of e-cigarette vapor is urgently needed.

Acute effects of short term use of e-cigarettes on airways physiology and respiratory symptoms in smokers with and without airways obstructive diseases and in healthy non smokers

“…Most of studies addressed the effect of e-cigarette in heart rate, blood pressure or heart beat instead of palpitations. Increased heart rate is a common finding 7,16 . Following short time e-cigarette use, a statistically significant decrease in oxygen saturation (SpO2) was noted in COPD patients who had already a lower baseline level compared with the other smoker groups.…”

“…However, in cell lines, e-cigarette vapour increases oxidative stress, inflammation 4,5 , may influence susceptibility to virus infection 6 and induces DNA strand breaks and cell death 7 on airway epithelial cells. It is also cytotoxic, induces apoptosis in fibroblats 8 , initiate inflammation at Kupffer 9 and enthothelial 10 cells, and alters vascular smooth muscle cells 11 .…”

Evaluación de los niveles de dependencia de la nicotina en usuarios de cigarrillos electrónicos

“…Los datos recientes sobre la prevalencia de los cigarrillos electrónicos en muestras europeas y americanas indican que, hasta la fecha, casi el 6,8% de adultos usa los cigarrillos electrónicos (McMillen, Gottlieb, Shaefer, Winickoff, y Klein, 2015). No obstante, esta popularidad creciente ha generado un debate en la salud pública respecto de su seguridad y efectividad como alternativa de cesación tabáquica (Yu et al, 2016). Estudios sobre los cigarrillos electrónicos y la cesación tabáquica han ofrecido resultados mixtos.…”

Analysis of electronic cigarette use among Polish dental students

“…What is more, Farsalinos et al 17 showed that cinnamon-flavored liquids have a cytotoxic influence on myoblasts isolated from rats' hearts. Furthermore, Yu et al 18 presented findings of changes in the DNA which resulted from e-cigarette aerosol, which were similar to those caused by tobacco smoke.…”