Liver cancer: Gut microbiota feeds obesity-induced liver cancer

摘要

The worldwide increase in obesity means that it has reached epidemic proportions, and obesity is associated with an increased risk of multiple types of cancer. The mechanisms that underlie obesity-associated cancer, however, are poorly understood. Previous studies have shown that senescent cells release inflammatory cytokines and proteases as part of the senescence-associated secretory phenotype (SASP) in response to oncogenic activation. Some SASP factors, such as IL-6 and PAI-1, are known to increase the risk of cancer in obese individuals. Thus, Eiji Hara and coauthors wanted to explore whether SASP contributes to obesity-associated cancer. In a previous study, Hara and his team had already established a system to visualize the dynamics of the cellular senescence response in living animals. The researchers used a mouse strain in which expression of a gene that induces the SASP could be monitored noninvasively using a bioluminescence imaging technique. Tumour initiation with DMBA (a chemical carcinogen that causes Ras mutations at high frequency) caused luminescence in the abdomens of obese mice that were fed a high-fat diet.