DNTP study shows how cobalt may cause cancer
Cobalt metal dust may cause lung cancer in rodents and humans by inducing oxidative stress in cells, according to researchers from the Division of the National Toxicology Program (DNTP). Cobalt metal powder is used in the production of alloys, ceramics, batteries, and dyes, with numerous industrial applications.
Occupational inhalation exposure to cobalt alloys is known to cause lung cancer, but the health hazards due to pure cobalt metal are poorly understood. DNTP has demonstrated that inhalation of pure cobalt metal dust for two years also increases lung cancer incidences in rodents.
In the new study, the researchers showed that exposure to cobalt metal ions triggers a process called oxidative stress, which is caused by the excessive buildup of free radicals, or reactive oxygen species, that damage DNA, proteins, and lipids. Cobalt metal-induced oxidative stress was demonstrated in human respiratory epithelial cells. DNA adducts due to oxidative stress were demonstrated in lung tissues from mice exposed to cobalt metal particles. Moreover, analysis of mouse lung tumors from this study revealed significant alterations in PI3K/AKT and MAPK signaling pathways that were previously implicated in human cancers.
Overall, the findings are consistent with a large body of evidence suggesting that oxidative stress is a major cause of metal-induced toxicity and various cancers across species. (JW)
Citation: Ton TT, Kovi RC, Peddada TN, Chhabria RM, Shockley KR, Flagler ND, Gerrish KE, Herbert RA, Behl M, Hoenerhoff MJ, Sills RC, Pandiri AR. 2021. Cobalt-induced oxidative stress contributes to alveolar/bronchiolar carcinogenesis in B6C3F1/N mice. Arch Toxicol 95(10):3171–3190.