Abstract 1931: Evaluation of cholecystokinin receptor expression and function in non-small cell lung cancer

Abstract

Introduction: Lung cancer is the leading cause of cancer-related death in the United States, with nearly 85% of cases histologically classified as non-small cell lung cancer (NSCLC). A recent epidemiological study provides evidence of an increased risk ratio for NSCLC in association with adherence to a Western dietary pattern, which has a higher dietary fat content, compared to vegetarian or Tex-Mex dietary patterns. Our laboratory and others have measured increased tumor burden in murine models of NSCLC when feeding diets are high in fat compared to a standard rodent cereal diet. In our laboratory, increased tumor burden is associated with increased tumor multiplicity, but no change in proliferative markers (Ki-67 and pS6) were observed. Dietary fat increases both tumorigenesis in mouse models of pancreatic cancer and circulating levels of the gastrointestinal hormone cholecystokinin (CCK). Inhibition of CCK receptors antagonizes progression of precursor lesions in murine models of pancreatic cancer. Although CCK receptor expression has not been detected in normal human pulmonary tissue, the CCK-B receptor has been identified immunohistologically in human lung tumors. Further, the CCK-A receptor is expressed in normal murine pulmonary epithelium. Hypothesis: At concentrations approximating circulating levels in mice fed a high fat diet, CCK reduces apoptosis of NSCLC cells in vitro. Materials and Methods: The murine NSCLC cell line IO33 was grown in serum-replete RPMI 1640 or serum-deprived RPM 1640 with 0 to 1000 pM exogenous CCK-8 peptide added. Expression of CCK-A and CCK-B receptors were measured in IO33 and human NSCLC cell lines by qPCR. Apoptosis was assessed using a Caspase-3/7 peptide cleavage assay. Results: Expression of CCK-A and CCK-B receptors are reported in IO33 cells and 11 human lung cancer cell lines. Apoptosis of IO33 cells was significantly decreased by greater than 30% at CCK concentrations greater than 100pM (P < 0.03), which is the circulating concentration of CCK in mice fed a high fat diet. Conclusions: CCK receptors are expressed in human and murine NSCLC cells and circulating CCK may reduce NSCLC cell apoptosis. Citation Format: Alexander C. Miller, Shelby J. Subry, Manijeh M. Assar, Krista Pearman, Jeffrey William Norris. Evaluation of cholecystokinin receptor expression and function in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1931.