ALDH2 Repression Promotes Lung Tumor Progression via Accumulated Acetaldehyde and DNA Damage

The major role of aldehyde dehydrogenase 2 family (ALDH2) is to detoxify acetaldehyde (ACE) to non-toxic acetic acid. Many evidences suggest that ALDH2 dysfunction contributes to a variety of human diseases including cancer. However, the biological function and molecular mechanism of ALDH2 in tumor progression remain elusive. In this study, we found that ALDH2 repression was associated with poor prognosis in lung adenocarcinoma. Overexpression of ALDH2 inhibited malignant features of lung adenocarcinoma cells, such as proliferation, stemness and migration, whereas ALDH2 knockdown increased these features. Mechanistically, ALDH2 repression led to accumulation of ACE; whereas ACE enhanced the migration features of lung adenocarcinoma cells, which was associated with increased DNA damage. Importantly, accumulated ACE and increased DNA damage were identified in Aldh2-knockout (KO) mouse lung tissues in vivo. Consistent with this concept, treatment of lung adenocarcinoma cells with ALDH2 agonist Alda-1 suppressed the proliferation, stemness and migration features of lung adenocarcinoma cells. Thus, activating ALDH2, such as via its agonist, may provide a novel strategy for treatment of lung cancer.