HNRNPC lactylation promotes pancreatic cancer progression through mediating the alternative splicing of PAK6.

Pancreatic cancer (PC) is a highly malignant and lethal tumor in gastrointestinal tract. Lactate accumulation is a classical feature of metabolic reprogramming in cancers. Lactate-derived lysine lactylation (Kla) is identified as a new type of post-translational modifications (PTMs), which is confirmed to be involved in multiple biological processes. However, the cancer-specific regulation of protein Kla in PC requires further elucidation. Here, we report a range of dysregulated Kla sites specifically related to RNA splicing in human pancreatic cancer, leading to the observation that the Kla at lysine 176 of heterogeneous nuclear ribonucleoprotein C (HNRNPC K176la) is significantly elevated in PC. Blocking HNRNPC K176la dramatically inhibits pancreatic cancer growth and metastasis. Mechanistically, K176la strengthened the binding of HNRNPC with poly-U motifs in p21-activated kinase 6 (PAK6) pre-mRNA, facilitating the expression of the oncogenic isoform PAK6S. Therefore, our study identifies a number of cancer-specific Kla sites spanned on alternative splicing (AS)-related proteins and unravels the significance of HNRNPC K176la in RNA splicing and PC development.