How the epigenetic memory of a fish could help fight lung cancer in humans

Lung cancer is the second most common form of cancer in the United States and the leading cause of cancer death in the US, according to the American Cancer Society.  A major cause of lung cancer is the production of genetic mutations caused by interactions between polycyclic aromatic hydrocarbon (PAH) molecules and the CYP1A gene. 

 PAH molecules are byproducts of the combustion of organic materials and are present in cigarette smoke, coal-fired power plant emissions, vehicle exhaust, and wildfire smoke. In addition to being found in the air, PAHs are also prevalent in soils and waterways due to interactions with the water cycle. 

A new study from OccHealthSci researchers, published in the journal Scientific Reports, examines a population of wild fish, called mummichogs (Fundulus heteroclitus), that live in PAH-polluted waters in the Elizabeth River in Virginia. These remarkable fish have developed genetic adaptations that mitigate the harmful effects caused by interactions between the CYP1A gene and PAHs. Mummichogs, the researchers say, use epigenetic memory, or the process of passing down certain gene expression patterns from one generation to the next, to manage this cancer-reducing feat.  

According to the researchers, understanding how this epigenetic memory works to blunt the interactions between CYP1A and PAHs in mummichogs is the first step in developing preventive or therapeutic strategies that could one day reduce the risk of cancer in humans exposed to PAHs. The researchers hypothesize that preventing the sustained increase in CYP1A1 expression will reduce lung cancer rates associated with environmental exposure.

The study, which included OccHealthSci researchers Samantha Carrothers, Emma Weeks, Assistant Professor Caren Weinhouse and colleagues, demonstrates the intricate ways organisms can adapt to environmental stressors and how we can learn from those adaptations to respond to similar health risks in human populations. 

This groundbreaking research illuminates the mummichog's adaptability to pollution and emphasizes the urgent need for further studies to understand the complexities of epigenetic responses across different organisms.