The tumor suppressor Adenomatous polyposis coli regulates T lymphocyte migration. Insights from familial polyposis patients

Adenomatous polyposis coli (APC) is a tumor suppressor whose mutations underlie familial adenomatous polyposis (FAP) and colorectal cancer. Although its role in intestinal epithelial cells is well characterized, APC importance for anti-tumor immunity is ill defined. APC regulates cytoskeleton organization, cell polarity and migration in various cells types. Here we address whether APC plays a role in T lymphocyte migration, a key step of anti-tumor immune responses. Using a series of cell biology tools, we demonstrated that T cells from FAP patients carrying APC mutations display adhesion and migration defects. Concomitantly, they presented lower expression of the integrin VLA-4. To further dissect the cellular mechanisms underpinning these defects, we depleted APC in the CEM T cell line. We found that APC is critical not only for VLA-4-dependent adhesion but also for actomyosin and microtubule organization in migrating T cells. Finally, APC-silenced CEM cells preferentially adopt an ameboid-like migration featuring unstructured pseudopodia and blebbing. These findings underscore a role of APC in T cell migration via modulation of integrin-dependent adhesion and cytoskeleton reorganization. Hence, APC mutations in FAP patients not only drive intestinal neoplasms, but also impair T cell migration, potentially leading to inefficient T cell-mediated anti-tumor immunity.