A new conditional Apc-mutant mouse model for colorectal cancer.

Area of Science:

• Genetics
• Cancer Biology
• Animal Models

Background:

• Mutations in the adenomatous polyposis coli (APC) gene cause familial adenomatous polyposis (FAP), a condition leading to numerous large intestinal tumors.
• Existing mouse models for FAP primarily develop tumors in the small intestine, limiting their utility for studying large intestinal cancers.

Purpose of the Study:

• To develop a novel conditional Apc-mutant mouse model that accurately replicates large intestinal tumor development.
• To create a tool for investigating the prevention and treatment of colorectal cancer.

Main Methods:

• Generation of a conditional Apc-mutant allele, Apc(15lox), with exon 15 flanked by loxP sites.
• Utilizing Cre-loxP recombination to induce deletion of exon 15 in specific intestinal tissues.
• Comparing tumor development and survival in different genetically modified mouse lines.

Main Results:

• The conditional Apc(15lox) allele allowed for targeted deletion of functional Apc domains.
• Germline deletion resulted in a severe phenotype with small intestinal tumors and early lethality.
• Conditional deletion in the distal small and large intestine (FabplCre;Apc(15lox/+)) led to predominant large intestinal tumors and longer survival.

Conclusions:

• The FabplCre;Apc(15lox/+) mouse model effectively mimics human FAP and sporadic colorectal cancer.
• This new model is a valuable tool for colorectal cancer research, including prevention and treatment strategies.