Alzheimer's disease-related mutations in APP influence colorectal tumor formation in a sex-dependent manner.

Cancer and Alzheimer's disease (AD) are age-associated diseases. Studies have indicated common mechanisms and interactions between these conditions. Epidemiological data demonstrate negative correlations between several cancers and AD. Despite this, few studies have explored their mutual influence on pathological outcomes. We utilized a human amyloid precursor protein (APP) mutant knock-in AD mouse model to investigate how familial mutations influence colorectal cancer development. Using a colitis-associated colorectal cancer (CAC) model, APP mutations promoted colon tumor formation in male mice but inhibited it in female mice. Correspondingly, inflammatory changes were reduced in the colons of female mice. Transcriptome analysis revealed differential expression, particularly in the enrichment of neuronal marker, steroid hormone, and immune cell signaling pathways. Additionally, distinct macrophage subtypes and neuronal profiles were observed in the colons of male and female APP mutant mice. These findings provide the first elucidation of the sex-dependent effects of APP mutations on colon cancer formation.