Transplantation of feces from mice with Alzheimer's disease promoted lung cancer growth.

ABSTRACT

BACKGROUND: Alzheimer's disease (AD) is a progressive neurologic disorder that causes the brain to shrink and brain cells to die. Lung cancer is characterized by high morbidity and mortality, late diagnosis and poor prognosis. And there is no specific mechanism to explain the epidemiological correlation between AD and lung cancer. MATERIALS AND METHODS: Lewis lung cancer cells (LLC) were injected into the left forelimb armpit of APP/PS1 mice to establish a tumor-bearing model. After remodeling the gut microbiota by fecal microbiota transplantation (FMT), the tumor were collected and analyzed for tumor size, Western blotting, and 16S rRNA gene sequencing. RESULTS: Compared with the control group, the AD FMT group showed larger tumors, while C57 FMT group showed smaller tumors. The former group showed the inhibition of AKT/Bax/Bcl-2 pathway, while the latter showed promotion of Caspase-1/IL-1ß and AKT/Bax/Bcl-2 pathway, which induced changes in tumor size. And Prevotella, Prevotella, Mucispirillum and Halomonas in the gut lumen of LLC tumor-bearing mice are increased, and Bacteroides, Coprobacillus, Bifidobacterium, Faecalibacterium and Aggregatiacter are decreased significantly. CONCLUSION: AD and lung cancer showed a positive correlation in APP expression, which proposed a different view from epidemiology on the correlation between AD and lung cancer.