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

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.