Elys deficiency constrains Kras-driven tumour burden by amplifying oncogenic stress

ABSTRACT The nucleoporin ELYS, encoded by AHCTF1 , is a large multifunctional protein with essential roles in nuclear pore assembly and mitosis. Using a zebrafish model of hepatocellular carcinoma, in which the expression of an inducible mutant kras transgene (kras G12V ) drives hepatocyte-specific hyperplasia and liver enlargement, we show that reducing ahctf1 gene dosage by 50% markedly shrinks tumour burden, while non-hyperplastic tissues are unaffected. We demonstrate that ahctf1 heterozygosity impairs nuclear pore formation, mitotic spindle assembly and chromosome segregation, leading to DNA damage and activation of TP53-dependent and independent mechanisms of cell death and cell cycle arrest. This selective vulnerability of cancer cells to mild disruption of Elys function uncovers a novel synthetic lethal interaction between ahctf1 and kras mutations that could be exploited therapeutically. Heterozygous expression of both ahctf1 and ranbp2 , or treatment of heterozygous ahctf1 larvae with the nucleocytoplasmic transport inhibitor, Selinexor, completely blocked kras G12V -driven hepatocyte hyperplasia, revealing promising avenues for combinatorial treatments.