SAT266 Transcriptional Changes Associated with Loss of Function of Fumarate Hydratase in A Cellular Model of Pheochromocytoma

Disclosure: C.L. Hall: None. J.E. Read: None. G. Salsbury: None. E. Lim: None. S. Akker: None. P. Chapple: None. Mutations in fumarate hydratase (FH) predispose to development of pheochromocytomas and paragangliomas (PPGLs), as well as leiomyomas and renal cell carcinoma. Loss of FH function leads to accumulation of fumarate which acts as an oncometabolite to drive tumorigenesis, although the molecular mechanisms leading to the development of these rare tumours are not fully understood. We have used CRISPR/Cas9 genome editing to generate a series of FH knockouts in the PC-12 cell line, derived from MAX-mutated pheochromocytoma in rat. Our knockout cell lines were used as a model to investigate the molecular consequences of loss of FH function. Comparison of the transcriptome of FH knockout cells with isogenic controls identified 1016 differentially expressed genes (adjusted p<0.05 Log2fold±1). This list of differentially expressed genes was then analysed to identify cellular pathways that were dysregulated in the absence of FH. Canonical pathways that were significantly altered, based on transcript expression relative to controls, included axonal signalling pathway (p=7.29x10-11), wound healing signalling pathway (p=1.74x10-07), pulmonary fibrosis idiopathic signalling pathway (p=4.10x10-07) and IL-15 production (p=1.03x10-05). Our results suggest cell adhesion and immune regulation pathways may be relevant to the development of PPGLs with germline mutations in FH, but will require validation in the context of human tissue. We have also performed metabolic flux analysis to identify differences in metabolite profile associated with loss of FH. Interestingly, changes in gene expression, revealed by our transcriptomic analysis, may explain some alterations in cellular metabolism of FH knockout cells. Presentation: Saturday, June 17, 2023