BIOL-16. OBESOGENIC DIET EXPOSURE INCREASES NF1-OPTIC PATHWAY GLIOMA FORMATION IN PART THROUGH EFFECTS ON THE CELL OF ORIGIN

Pediatric low-grade glioma incidence has been rising in the U.S. over the last 20 years, concurrent with a rising rate of obesity in both the adult and pediatric populations. Recently, children of obese mothers have been demonstrated to have increased rates of several tumors, including brain tumors. Importantly, obesity in the U.S. is driven in large part by diet, given the abundance and accessibility of high-fat, high-sugar food choices. High-fat diet exposure has been previously demonstrated to promote proliferation and glial differentiation of embryonic neuroglial progenitor cells (NPCs) around the third ventricular zone (TVZ), suggesting that in utero exposure to an obesogenic diet might affect the formation of pediatric tumors derived from these cells, such as Neurofibromatosis Type 1 (NF1)-related optic pathway glioma (OPG). Based on these data, we hypothesized that maternal obesogenic exposure would increase Nf1-OPG formation through intrinsic effects on the tumor cell of origin. We demonstrated that progeny from obese dams exposed to HFHS diet during and preceding gestation demonstrated increased proliferation and glial differentiation of WT and Nf1-heterozygous TVZ NPCs in vivo. Progeny of non-obese dams exposed to this diet during gestation demonstrated a similar phenotype, suggesting these effects were related to maternal diet rather than weight. We then assessed how obesogenic diet exposure affected tumor formation. We determined that this exposure increases glioma penetrance in two low-penetrance models of NF1-OPG. Finally, we demonstrated that obesogenic diet exposure resulted in earlier tumor onset in a high-penetrance Nf1-OPG model. Taken together, these findings suggest that obesogenic diet exposure increases pediatric glioma formation, in part through effects on the tumor cell of origin while still in utero. It may also have implications for clinical prognosis, as earlier age of tumor onset has been negatively associated with visual outcomes in NF1-OPG.