Exploiting WEE1 kinase activity as FUS::DDIT3-dependent therapeutic vulnerability in myxoid liposarcoma

Abstract

AbstractThe pathognomonic FUS::DDIT3 fusion protein drives myxoid liposarcoma (MLS) tumorigenesis via aberrant transcriptional activation of oncogenic signaling. Since FUS::DDIT3 has so far not been pharmacologically tractable to selectively target MLS cells, this study investigated the functional role of the cell cycle regulator WEE1 as novel FUS::DDIT3-dependent therapeutic vulnerability in MLS. Here we demonstrate that enhanced WEE1 pathway activity represents a hallmark of FUS::DDIT3-expressing cell lines as well as MLS tissue specimens and that WEE1 is required for MLS cellular survivalin vitroandin vivo. Pharmacologic inhibition of WEE1 activity results in DNA damage accumulation and cell cycle progression forcing cells to undergo apoptotic cell death. In addition, our results uncover FUS::DDIT3-dependent WEE1 expression as an oncogenic survival mechanism to tolerate high proliferation and resulting replication stress in MLS. Fusion protein-driven G1/S cell cycle checkpoint deregulation via overactive Cyclin E/CDK2 complexes thereby contributes to enhanced WEE1 inhibitor sensitivity in MLS. These findings identify WEE1-mediated replication stress tolerance as molecular vulnerability in FUS::DDIT3-driven MLS tumorigenesis that could represent a novel target for therapeutic intervention.