Moon-Shong Tang Ph.D.

The number of people who use e-cigarettes is rapidly rising, so it is increasingly important to understand whether e-cigarette aerosol may lead to lung cancer. E-cigarettes contain nicotine, and e-cigarette aerosol does not involve burning tobacco leaves. As a result, e-cigarettes are promoted as non-carcinogenic. As a first step to test the cancer-causing potential of e-cigarette smoke, we measured DNA damage induced by nicotine in human lung cells and the lungs of mice exposed to the e-cigarette smoke. We have found that nicotine and e-cigarette aerosol induce not only DNA damage but also reduce DNA repair, and enhances the susceptibility to genetic mutation and transformation into tumors. We will further test e-cigarette aerosol in mouse models and analyze the changes in DNA and the effects on DNA repair. Establishing the cancer-causing potential of e-cigarette aerosol and understanding its mechanisms will dispel the claim that e-cigarettes are safe and might discourage their use.

Update:

We have found that in a short-term exposure, E-cig aerosol (ECA) induces DNA damage and impairs DNA repair functions in mouse lung tissues and that nicotine alone induces the same effect in human lung epithelial cells. In a long-term exposure, ECA induces lung adenocarcinoma (the most common type of non-small cell lung cancer) and an increased number of cells lining the urinary tract in mice. These results indicate that ECA is a lung carcinogen in mice and potentially in humans. We are in the process of identifying the crucial gene mutations induced by ECA that drive lung cancer and the spectrum of genetic mutations by sequencing the whole genomic DNA isolated from lung adenocarcinoma, their surrounding tissues and cancer-free counterparts.