LAUSR

BACKGROUND AND AIM Promoted by pancreatitis, oncogenic KrasG12D triggers acinar cells' neoplastic transformation through acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN). Agr2 (anterior gradient 2), a known inhibitor of p53, is detected at early stage of pancreatic ductal adenocarcinoma (PDAC) development. RNA polymerase II (RNAPII) is a key nuclear enzyme; regulation of its nuclear localization in mammalian cells represents a potential therapeutic target. METHODS A mouse model of inflammation-accelerated KrasG12D-driven ADM and PanIN development was used. Pancreas-specific Agr2 ablation was performed to access its role in pancreatic carcinogenesis. Hydrophobic hexapeptides loaded in liposomes were developed to disrupt Agr2-RNAPII complex. RESULTS We found that Agr2 is upregulated in ADM-to-PanIN transition in inflammation and KrasG12D-driven early pancreatic carcinogenesis. Genetic ablation of Agr2 specifically blocks this metaplastic-to-neoplastic process. Mechanistically, Agr2 directs the nuclear import of RNAPII via its C-terminal nuclear localization signal, undermining the ATR-dependent p53 activation in ADM lesions. Since Agr2 binds to the largest subunit of RNAPII in a peptide motif-dependent manner, we developed a hexapeptide to interfere with the nuclear import of RNAPII by competitively disrupting the Agr2-RNAPII complex. This novel hexapeptide leads to dysfunction of RNAPII with concomitant activation of DNA damage response in early neoplastic lesions; hence, it dramatically compromises PDAC initiation in vivo. Moreover, the hexapeptide sensitizes PDAC cells and patient-derived organoids harbouring wild-type p53 to RNAPII inhibitors and first-line chemotherapeutic agents in vivo. Of note, this therapeutic effect is efficient across various cancer types. CONCLUSION Agr2 is identified as a novel adaptor protein for nuclear import of RNAPII in mammalian cells. Also, we provide genetic evidence defining Agr2-dependent nuclear import of RNAPII as a pharmaceutically accessible target for prevention and treatment in PDAC in the context of wild-type p53.