PTK6 drives HNRNPH1 phase separation to activate autophagy and suppress apoptosis in colorectal cancer.

Macroautophagy/autophagy is the principal mechanism that mediates the delivery of various cellular cargoes to lysosomes for degradation and recycling, and has been reported to play a crucial role in colorectal cancer (CRC) pathogenesis and progression. Targeting autophagy may be a promising therapeutic strategy for CRC. However, the specific functions and potential mechanisms of autophagy in CRC remain unclear. In the present study, we discovered that PTK6 (protein tyrosine kinase 6) could activate autophagy and inhibit CRC apoptosis. PTK6 physically interacted with HNRNPH1 and mediated tyrosine phosphorylation at Y210 of HNRNPH1, which promoted the latter's liquid-liquid phase separation (LLPS). Furthermore, LLPS of HNRNPH1 formed biomolecular condensates and triggered splicing-switching of the NBR1 exon 10 inclusion transcript, thereby activating autophagy and suppressing apoptosis of CRC. Additionally, PDO and CDX models indicated that tilfrinib, an inhibitor targeting PTK6, could inhibit CRC growth. Overall, our findings reveal the novel PTK6-HNRNPH1-NBR1 regulatory autophagy axis and provide a potential therapy target for CRC.Abbreviation: 1,6HD: 1,6-hexanediol, CQ: chloroquine, CRC: colorectal cancer, DFS: disease-free survival, FRAP: fluorescence recovery afterphotobleaching, GSEA: Gene Set Enrichment Analysis, GTEx: Genotype-Tissue Expression, HNRNPH1: heterogeneous nuclearribonucleoprotein H1, IDRs: intrinsically disordered regions, IHC: immunohistochemical, KEGG: Kyoto Encyclopedia of Genes and Genomes,LLPS: liquid-liquid phase separation, NBR1: NBR1 autophagy cargoreceptor, OS: overall survival, PDO: patient-derivedorganoid, PTK6: protein tyrosine kinase 6, PTMs: post-translationalmodifications, SE: skipped exon, TCGA: The Cancer Genome Atlas, TEM: transmission electron microscopy, TMA: tissue microarray, TyrKc: tyrosine kinase catalytic.