cholecystokinin and Neoplasm-Metastasis

Obesity and dietary fat are associated with increased risk of several malignancies including pancreatic cancer. The incidence of pancreatic cancer is increased in countries that consume diets high in fat.. The purpose of this study was to assess the relationship and mechanism of action between dietary fat and endogenous cholecystokinin (CCK) on pancreatic tumor growth and metastasis in an immunocompetent animal model.. C57BL/6 mice were placed on regular, low-fat, or high-fat diets for 8 weeks before establishment of Panc-02 orthotopic pancreatic tumors. Mice were then treated with a CCK-A receptor antagonist, devazepide, or vehicle for an additional 2.5 weeks. Pancreas tumors were weighed and metastases counted. Blood CCK levels were measured by radioimmunoassay (RIA). Tissues were examined histologically and studied for genes associated with metastasis by RT-PCR array. Effects of the CCK antagonist on Panc-02 cells invasiveness was assessed in a Matrigel invasion assay.. Mice that received the high-fat diet had larger tumors and tenfold higher serum CCK levels by RIA compared to normal diet controls (p < 0.01). Pancreatic tumors in high-fat diet mice treated with the antagonist had fewer intravascular tumor emboli and metastases compared to controls. The reduction in tumor emboli correlated with decreased vascular endothelial growth factor-A (VEGF-A) expression in tumors (p < 6 × 10(-9)). In vitro invasiveness of Panc-02 cells also was reduced by CCK-A receptor antagonist treatment (p = 1.33 × 10(-6)).. CCK is a mediator of dietary fat-associated pancreatic cancer. CCK is also involved in the invasiveness of pancreatic tumors through a mechanism involving VEGF-A.

Topics: Animals; Blood Glucose; Cell Line, Tumor; Cholecystokinin; Devazepide; Dietary Fats; Dose-Response Relationship, Drug; Embolism; Hormone Antagonists; Male; Mice; Mice, Inbred C57BL; Neoplasm Invasiveness; Neoplasm Metastasis; Pancreatic Neoplasms; Radioimmunoassay

The high sensitivity of pentagastrin stimulation in detecting primary or metastatic medullary thyroid cancer (MTC) suggests widespread expression of the corresponding receptor type on human MTC. Indeed, autoradiographic studies have demonstrated cholecystokinin (CCK)-B/gastrin receptors not only in more than 90% of MTCs but also in a high percentage of small cell lung cancers, some ovarian cancers, astrocytomas and potentially a variety of adenocarcinomas. The aim of this study was to systematically screen and optimize, in a preclinical model and a pilot clinical study, suitable radioligands for targeting CCK-B receptors in vivo.. A variety of CCK/gastrin-related peptides, all bearing the C-terminal CCK receptor-binding tetrapeptide sequence Trp-Met-Asp-PheNH2 or derivatives thereof, were studied. They were radioiodinated by the lodogen or Bolton-Hunter procedures. The peptides were members of the gastrin or CCK families, which differ by the intramolecular position of a tyrosyl moiety. Their stability and affinity were studied in vitro and in vivo; their biodistribution and therapeutic efficacy were tested in nude mice bearing subcutaneous human MTC xenografts. Diethylenetriamine pentaacetic acid (DTPA) derivatives of suitable peptides were synthesized successfully, and their preclinical and initial clinical evaluations were performed, labeled with 111In.. All members of the CCK or gastrin families were stable in serum (with half-lives of several hours at 37 degrees C); nevertheless, the stability of those peptides bearing N-terminal pGlu residues or D-amino acids was significantly higher. In accordance with their comparably low affinity, nonsulfated members of the CCK family showed fairly low uptake in the tumor and other CCK-B receptor-expressing tissues. Sulfated CCK derivatives performed significantly better but also displayed a comparably high uptake in normal CCK-A receptor-expressing tissues. This effect was probably due to their similar affinity for both CCK-A and CCK-B receptors. Best tumor uptake and tumor-to-nontumor ratios were obtained with members of the gastrin family because of their selectivity and affinity for the CCK-B receptor subtype. Pilot therapy experiments in MTC-bearing animals showed significant antitumor efficacy compared with untreated controls. DTPA derivatives of minigastrin were successfully developed. In a pilot clinical study, radioiodinated and 111In-labeled derivatives showed excellent targeting of physiological CCK-B receptor-expressing organs, as well as all known tumor sites.. CCK/gastrin analogs may be a useful new class of receptor-binding peptides for diagnosis and therapy of CCK-B receptor-expressing tumors, such as MTC or small cell lung cancer. Nonsulfated gastrin derivatives may be preferable because of their CCK-B receptor selectivity, hence lower accretion in normal CCK-A receptor-expressing organs.

Topics: Adult; Aged; Amino Acid Sequence; Animals; Carcinoma, Medullary; Carcinoma, Small Cell; Cholecystokinin; Data Interpretation, Statistical; Female; Gastrins; Humans; Indium Radioisotopes; Iodine Radioisotopes; Isotope Labeling; Lung Neoplasms; Lymphatic Metastasis; Male; Mice; Mice, Nude; Middle Aged; Molecular Sequence Data; Neoplasm Metastasis; Neoplasms, Experimental; Peptides; Radioisotopes; Radionuclide Imaging; Receptors, Cholecystokinin; Thyroid Neoplasms

Topics: Adenocarcinoma; Animals; Carcinogens; Cholecystokinin; Cricetinae; Disease Models, Animal; Neoplasm Metastasis; Nitrosamines; Pancreas; Pancreatic Juice; Pancreatic Neoplasms

Topics: Achlorhydria; Adenoma, Islet Cell; Adult; Animals; Bile; Biological Assay; Cholecystokinin; Diarrhea; Dogs; Female; Gastric Acidity Determination; Glucagon; Histamine; Humans; Hypokalemia; Liver Neoplasms; Male; Middle Aged; Neoplasm Metastasis; Pancreatic Neoplasms; Secretin; Tissue Extracts