NFS-10. ROLE OF CDKN2A CO-DELETION IN DRIVING TUMOR INVASIVENESS IN NF1 MUTANT GLIOMA

Abstract

Abstract BACKGROUND Neurofibromatosis type 1, caused by mutations in the NF1 gene, is a common autosomal dominant genetic disorder associated with an increased risk of glioma tumor development. A high occurrence of CDKN2a codeletion in NF1-mutant high-grade gliomas (HGG) compared to low-grade gliomas (LGG) implies a potential role of CDKN2a loss in the transformation of NF1-mutant LGG to HGG. In our study, we aimed to elucidate the role of NF1 and CDKN2a in tumor transformation using a panel of glioma cell line models with varying NF1 and CDKN2a expression. METHOD A diverse panel of glioma cell lines, encompassing LGG (1667-ON, RES259, RES186, JHH-NF1-PA1) and HGG (GBM511, GBM110, SF8628, U87-MG, TM-31, 7316-2189, 7316-3058, 7316-4917), was cultured. Their growth rates and invasiveness were further evaluated using cell proliferation and Boyden chamber invasiveness assays. RESULTS LGG cell lines exhibited relatively lower growth rates and invasiveness compared to their high-grade counterparts. Intriguingly, RES259, a LGG cell line harboring both NF1 and CDKN2a variants, demonstrated the highest growth rate and invasiveness among LGG cell lines, surpassing even those with intact NF1 and CDKN2a, such as JHH-NF1-PA1 and RES186. To further elucidate the roles of NF1 and CDKN2a, CRISPR-Cas9 technology was employed to knockout these genes individually and in various combinations in RES186. Our findings unveiled that sole NF1 knockout had negligible impact on RES186. Conversely, CDKN2a knockout increased both growth rate and invasiveness. Strikingly, the codeletion of NF1 and CDKN2a in RES186 significantly exacerbated its growth rate and invasiveness. These results underscore the intricate interplay of NF1 and CDKN2a in governing the growth and invasiveness dynamics of glioma cells. CONCLUSION In conclusion, our preliminary study suggests that the concurrent loss of NF1 and CDKN2a promotes enhanced growth and invasiveness in gliomas, shedding light on the collaborative role of these genetic alterations in tumor transformation.