AGR2-Dependent Nuclear Import of RNA Polymerase II Constitutes a Specific Target of Pancreatic Ductal Adenocarcinoma in the Context of Wild-Type p53

Gastroenterology. 2021 Nov;161(5):1601-1614.e23. doi: 10.1053/j.gastro.2021.07.030. Epub 2021 Jul 23.

Abstract

Background & aims: Promoted by pancreatitis, oncogenic KrasG12D triggers acinar cells' neoplastic transformation through acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia. Anterior gradient 2 (Agr2), 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 pancreatic intraepithelial neoplasia 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 up-regulated in ADM-to-pancreatic intraepithelial neoplasia 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. Because 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 harboring wild-type p53 to RNAPII inhibitors and first-line chemotherapeutic agents in vivo. Of note, this therapeutic effect is efficient across various cancer types.

Conclusions: 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.

Keywords: Agr2; Hexapeptide; Metaplastic; Neoplastic; Pancreatic Cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Animals
  • Antineoplastic Agents / pharmacology
  • Carcinoma in Situ / drug therapy
  • Carcinoma in Situ / enzymology*
  • Carcinoma in Situ / genetics
  • Carcinoma in Situ / pathology
  • Carcinoma, Pancreatic Ductal / drug therapy
  • Carcinoma, Pancreatic Ductal / enzymology*
  • Carcinoma, Pancreatic Ductal / genetics
  • Carcinoma, Pancreatic Ductal / pathology
  • Cell Transformation, Neoplastic / genetics
  • Cell Transformation, Neoplastic / metabolism
  • Cell Transformation, Neoplastic / pathology
  • Gene Expression Regulation, Neoplastic
  • Metaplasia
  • Mice, Inbred C57BL
  • Mice, Inbred NOD
  • Mice, Knockout
  • Mice, SCID
  • Mucoproteins / genetics
  • Mucoproteins / metabolism*
  • Mutation
  • Oligopeptides / pharmacology
  • Oncogene Proteins / genetics
  • Oncogene Proteins / metabolism*
  • Pancreatic Neoplasms / drug therapy
  • Pancreatic Neoplasms / enzymology*
  • Pancreatic Neoplasms / genetics
  • Pancreatic Neoplasms / pathology
  • Proto-Oncogene Proteins p21(ras) / genetics
  • RNA Polymerase II / genetics
  • RNA Polymerase II / metabolism*
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*

Substances

  • Agr2 protein, mouse
  • Antineoplastic Agents
  • Mucoproteins
  • Oligopeptides
  • Oncogene Proteins
  • Trp53 protein, mouse
  • Tumor Suppressor Protein p53
  • RNA Polymerase II
  • Hras protein, mouse
  • Proto-Oncogene Proteins p21(ras)