ADAMDEC1 maintains a novel growth factor signaling loop in cancer stem cells

Glioblastomas (GBM) are lethal brain tumors where poor outcome is attributed to cellular heterogeneity, therapeutic resistance, and a highly infiltrative nature. These characteristics are preferentially linked to GBM cancer stem cells (GSCs), but how GSCs maintain their stemness is incompletely understood and the subject of intense investigation. Here, we identify a novel signaling loop that induces and maintains GSCs. This loop consists of an atypical metalloproteinase, a disintegrin and metalloproteinase domain-like protein decysin 1 (ADAMDEC1), secreted by GSCs. ADAMDEC1 rapidly solubilizes fibroblast growth factor-2 (FGF2) to stimulate FGF receptor 1 (FGFR1) expressed on GSCs. This signaling axis induces upregulation of Zinc finger E-box-binding homeobox 1 (ZEB1) that regulates ADAMDEC1 expression, creating a positive feedback loop. Genetic or pharmacological targeting of components of this axis attenuates self-renewal and tumor growth. These findings reveal a new signaling axis for GSC maintenance and highlight ADAMDEC1 and FGFR1 as potential therapeutic targets in GBM.Statement of SignificanceCancer stem cells (CSC) drive tumor growth in many cancers including glioblastoma. We identified a novel sheddase, a disintegrin and metalloproteinase domain-like protein decysin 1, that initiates a fibroblast growth factor autocrine loop to promote stemness in CSCs. This loop can be targeted to reduce glioblastoma growth.