Loss of Rnf43 Accelerates Kras-Mediated Neoplasia and Remodels the Tumor Immune Microenvironment in Pancreatic Adenocarcinoma
Hosein, Abdel Nasser; Dangol, Gita; Okumura, Takashi; Roszik, Jason; Rajapakshe, Kimal; Siemann, Megan; Zaid, Mohamed; Ghosh, Bidyut; Monberg, Maria; Guerrero, Paola A.; Singhi, Aatur; Haymaker, Cara L.; Clevers, Hans; Abou-Elkacem, Lotfi; Woermann, Sonja M.; Maitra, Anirban
(2022) Gastroenterology, volume 162, issue 4, pp. 1303 - 1318.e18
(Article)
Abstract
Background & Aims: RNF43 is an E3 ubiquitin ligase that is recurrently mutated in pancreatic ductal adenocarcinoma (PDAC) and precursor cystic neoplasms of the pancreas. The impact of RNF43 mutations on PDAC is poorly understood and autochthonous models have not been characterized sufficiently. In this study, we describe a genetically
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engineered mouse model (GEMM) of PDAC with conditional expression of oncogenic Kras and deletion of the catalytic domain of Rnf43 in exocrine cells. Methods: We generated Ptf1a-Cre;LSL-KrasG12D;Rnf43flox/flox (KRC) and Ptf1a-Cre; LSL-KrasG12D (KC) mice and animal survival was assessed. KRC mice were sacrificed at 2 months, 4 months, and at moribund status followed by analysis of pancreata by single-cell RNA sequencing. Comparative analyses between moribund KRC and a moribund Kras/Tp53-driven PDAC GEMM (KPC) was performed. Cell lines were isolated from KRC and KC tumors and interrogated by cytokine array analyses, ATAC sequencing, and in vitro drug assays. KRC GEMMs were also treated with an anti-CTLA4 neutralizing antibody with treatment response measured by magnetic response imaging. Results: We demonstrate that KRC mice display a marked increase in incidence of high-grade cystic lesions of the pancreas and PDAC compared with KC. Importantly, KRC mice have a significantly decreased survival compared with KC mice. Using single-cell RNA sequencing, we demonstrated that KRC tumor progression is accompanied by a decrease in macrophages, as well as an increase in T and B lymphocytes, with evidence of increased immune checkpoint molecule expression and affinity maturation, respectively. This was in stark contrast to the tumor immune microenvironment observed in the KPC PDAC GEMM. Furthermore, expression of the chemokine CXCL5 was found to be specifically decreased in KRC cancer cells by means of epigenetic regulation and emerged as a putative candidate for mediating the unique KRC immune landscape. Conclusions: The KRC GEMM establishes RNF43 as a bona fide tumor suppressor gene in PDAC. This GEMM features a markedly different immune microenvironment compared with previously reported PDAC GEMMs and puts forth a rationale for an immunotherapy approach in this subset of PDAC cases.
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Keywords: Genetically Engineered Mouse Models, KRAS, Pancreatic Cancer, Single-Cell RNA Sequencing, Tumor Suppressor Gene, Epigenesis, Genetic, Humans, Proto-Oncogene Proteins p21(ras)/genetics, Pancreatic Neoplasms/pathology, Tumor Microenvironment, Carcinoma, Pancreatic Ductal/pathology, Animals, Adenocarcinoma/genetics, Mice, Ubiquitin-Protein Ligases/genetics, Disease Models, Animal, Gastroenterology, Hepatology, Research Support, Non-U.S. Gov't, Journal Article, Research Support, N.I.H., Extramural
ISSN: 0016-5085
Publisher: W.B. Saunders Ltd
Note: Funding Information: We thank the MD Anderson Epigenomics Profiling Core Facility for their assistance with ChIP-seq assay. Conflicts of interest This author discloses the following: Anirban Maitra receives royalties for a pancreatic cancer biomarker test from Cosmos Wisdom Biotechnology, and this financial relationship is managed and monitored by the University of Texas MD Anderson Cancer Center Conflict of Interest Committee. Anirban Maitra is also listed as an inventor on a patent that has been licensed by Johns Hopkins University to ThriveEarlier Detection. Anirban Maitra serves as a consultant for Freenome and Tezcat Biotechnology. The remaining authors disclose no conflicts. Funding Anirban Maitra is supported by National Institutes of Health grants R01 CA220236 and R01 CA218004. Anirban Maitraisis also funded by the Sheikh Khalifa Bin Zayed Foundation. Funding Information: For the anti-CTLA4 antibody KRC GEMM drug trial, radiographic response was defined as >30% decrease in tumor volume on MRI; radiographic stability was defined as between +30% and –30% change in tumor volume; radiographic progression was defined as >30% increase in volume of tumor; death was defined as moribund or dead animal before planned sacrifice time point. The small animal imaging facility is supported by University of Texas MD Anderson Cancer Center Clinical and Translational Research Center, which is funded by National Cancer Institute (CA16672). Funding Information: Funding Anirban Maitra is supported by National Institutes of Health grants R01 CA220236 and R01 CA218004. Anirban Maitraisis also funded by the Sheikh Khalifa Bin Zayed Foundation. Publisher Copyright: © 2022 AGA Institute
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