Loss of RARRES1 function Promotes Follicular Lymphomagenesis and Inhibits B cell Differentiation in Mice

Retinoic acid receptor responder 1 (RARRES1) is among the most commonly methylated loci in multiple cancers. RARRES1 regulates mitochondrial and fatty acid metabolism, stem cell differentiation, and survival of immortalized cell lines in vitro. Here, we created constitutive Roues1 knockout (Rarres1(-/-)) mouse models to study RARRES1 function in vivo. Rarres1(-/-) embryonic fibroblasts regulated tubulin glutamylation, cell metabolism, and survival, recapitulating RARRES1 function in immortalized cell lines. In two mouse strains, loss of Rarres1 led to a markedly increased dose-dependent incidence of follicular lymphoma (FL). Prior to lymphoma formation, Rarres1(-/-) B cells have compromised activation, maturation, differentiation into antibody-secreting plasma cells, and cell cycle progression. Rarres1 ablation increased B cell survival and led to activation of the unfolded protein response (UPR) and heat shock response (HSR). Rarres1 deficiency had differential effects on cellular metabolism, with increased bioenergetic capacity in fibroblasts, and minor effects on bioenergetics and metabolism in B cells. These findings reveal that RARRES1 is a bona fide tumor suppressor in vivo and the deletion in mice promotes cell survival, and reduces B cell differentiation with B cell autonomous and non-autonomous functions.

Automated summary

RARRES1 is commonly methylated in multiple cancers and regulates cell metabolism, stem cell differentiation, and survival. Knockout mouse models revealed that RARRES1 acts as a tumor suppressor in vivo and affects B cell activation, maturation, and differentiation.