Loss of the Tumor Suppressor FLCN Promotes Breast Tumor Growth by Inducing a TFE3-Dependent Program Driving Warburg Effect and Angiogenesis
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ABSTRACT: Growing tumors exist in metabolically compromised environments that require activation of multiple pathways to scavenge nutrients to support accelerated rates of growth. The FLCN tumor suppressor complex (FLCN, FNIP1, FNIP2) has been implicated in the regulation of energy homeostasis via two metabolic master kinases: AMPK and mTORC1. Loss-of-function mutations of the FLCN tumor suppressor complex have only been reported in renal tumors in patients with the rare Birt-Hogg-Dube syndrome. Here we reveal that FLCN, FNIP1, and FNIP2 are downregulated in many human cancers including poor prognosis invasive basal-like breast carcinomas where AMPK and TFE3 targets are activated compared to the luminal, less aggressive subtypes. We show that FLCN loss in luminal subtypes promotes tumor growth through TFE3 activation and subsequent induction of several pathways including autophagy, lysosomal biogenesis, aerobic glycolysis, and angiogenesis. Strikingly, induction of aerobic glycolysis and angiogenesis in FLCN deficient cells was dictated by the activation of PGC-1⍺/HIF-1⍺ pathway, which we show to be TFE3-dependent, directly linking TFE3 to Warburg metabolic reprogramming and angiogenesis. Thus, FLCN loss induces TFE3-dependent breast tumor growth through activation of multiple mechanisms, including previously unreported roles in aerobic glycolysis and angiogenesis. These findings could point to a general role of a deregulated FLCN/TFE3 tumor suppressor pathway in human cancers.
ORGANISM(S): Homo sapiens
PROVIDER: GSE163791 | GEO | 2020/12/23
REPOSITORIES: GEO
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