1. Netazepide inhibits expression of Pappalysin 2 in type-1 gastric neuroendocrine tumors
- Author
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Andrea Varro, Carrie A. Duckworth, Katie A. Lloyd, Yongxiang Fang, Stamatia Papoutsopoulou, Nathan Howes, Klaire Exarchou, Lucille Rainbow, Andrew R. Moore, D. Mark Pritchard, Neil Hall, Claus Oxvig, Michael D. Burkitt, Steven Dodd, Bryony N. Parsons, and Malcolm Boyce
- Subjects
HDC, histidine decarboxylase ,0301 basic medicine ,IGF, insulin-like growth factor ,Atrophic gastritis ,Carcinogenesis ,IGFBP3 ,Achlorhydria ,Benzodiazepines ,Mice ,0302 clinical medicine ,Pregnancy-Associated Plasma Protein-A ,Original Research ,Gastrin ,Benzodiazepinones ,Gene knockdown ,IGFBP, insulin-like growth factor binding protein ,Stomach ,Gastroenterology ,mRNA, messenger RNA ,Organoids ,MMP, matrix metalloproteinase ,Neuroendocrine Tumors ,Treatment Outcome ,medicine.anatomical_structure ,Gene Knockdown Techniques ,Cholecystokinin B receptor ,qPCR, quantitative polymerase chain reaction ,Immunohistochemistry ,030211 gastroenterology & hepatology ,Signal Transduction ,Primary Cell Culture ,PBS, phosphate-buffered saline ,TIMP, tissue inhibitors of metalloproteinases ,Mice, Transgenic ,CHGA, chromogranin A ,PAPPA2, pappalysin 2 ,03 medical and health sciences ,Stomach Neoplasms ,Cell Line, Tumor ,Gastrins ,CCK2R, cholecystokinin type-2 receptor ,medicine ,Animals ,Humans ,lcsh:RC799-869 ,Mouse Model ,Hepatology ,business.industry ,Phenylurea Compounds ,medicine.disease ,Hormone ,Receptor, Cholecystokinin B ,Disease Models, Animal ,030104 developmental biology ,gNET, gastric neuroendocrine tumor ,Gastric Mucosa ,siRNA, small interfering RNA ,ECL, enterochromaffin-like ,Tumorigenesis ,Cancer research ,lcsh:Diseases of the digestive system. Gastroenterology ,BSA, bovine serum albumin ,business - Abstract
Background & Aims In patients with autoimmune atrophic gastritis and achlorhydria, hypergastrinemia is associated with the development of type 1 gastric neuroendocrine tumors (gNETs). Twelve months of treatment with netazepide (YF476), an antagonist of the cholecystokinin B receptor (CCKBR or CCK2R), eradicated some type 1 gNETs in patients. We investigated the mechanisms by which netazepide induced gNET regression using gene expression profiling. Methods We obtained serum samples and gastric corpus biopsy specimens from 8 patients with hypergastrinemia and type 1 gNETs enrolled in a phase 2 trial of netazepide. Control samples were obtained from 10 patients without gastric cancer. We used amplified and biotinylated sense-strand DNA targets from total RNA and Affymetrix (Thermofisher Scientific, UK) Human Gene 2.0 ST microarrays to identify differentially expressed genes in stomach tissues from patients with type 1 gNETs before, during, and after netazepide treatment. Findings were validated in a human AGSGR gastric adenocarcinoma cell line that stably expresses human CCK2R, primary mouse gastroids, transgenic hypergastrinemic INS-GAS mice, and patient samples. Results Levels of pappalysin 2 (PAPPA2) messenger RNA were reduced significantly in gNET tissues from patients receiving netazepide therapy compared with tissues collected before therapy. PAPPA2 is a metalloproteinase that increases the bioavailability of insulin-like growth factor (IGF) by cleaving IGF binding proteins (IGFBPs). PAPPA2 expression was increased in the gastric corpus of patients with type 1 gNETs, and immunohistochemistry showed localization in the same vicinity as CCK2R-expressing enterochromaffin-like cells. Up-regulation of PAPPA2 also was found in the stomachs of INS-GAS mice. Gastrin increased PAPPA2 expression with time and in a dose-dependent manner in gastric AGSGR cells and mouse gastroids by activating CCK2R. Knockdown of PAPPA2 in AGSGR cells with small interfering RNAs significantly decreased their migratory response and tissue remodeling in response to gastrin. Gastrin altered the expression and cleavage of IGFBP3 and IGFBP5. Conclusions In an analysis of human gNETS and mice, we found that gastrin up-regulates the expression of gastric PAPPA2. Increased PAPPA2 alters IGF bioavailability, cell migration, and tissue remodeling, which are involved in type 1 gNET development. These effects are inhibited by netazepide., Graphical abstract
- Published
- 2020