sincalide and Pancreatic-Neoplasms

Pancreatic secretion can be influenced by cholecystokinin (CCK) either directly via actions on acinar cells or indirectly via actions on nerves. The presence and functional roles of CCK receptors on human pancreatic acinar cells remains unclear. In the current study human pancreatic acini were isolated and then treated with CCK-8, gastrin and/or carbachol. Functional parameters were measured including intracellular [Ca2+] and amylase secretion. It was observed that human acini did not respond to CCK agonists but did respond to carbachol with robust increases in functional parameters. Adenoviral-mediated gene transfer of CCK1 or CCK2 receptors to the human cells resulted in cell responses to CCK agonists. In order to determine the reason for the lack of responsiveness of the human acini, expression of receptor mRNAs was determined using quantitative RT-PCR and localized by in situ hybridization. mRNA levels for CCK1 receptors were approximately 30 times lower than those of CCK2 receptors, which were approximately 10 times lower than those of m3 Ach receptors as measured by quantitative PCR. Neither CCK1 nor CCK2 receptors were localized in adult human pancreas by in situ hybridization. These results indicate that human pancreatic acinar cells do not respond directly to CCK receptor activation and this is likely due to an insufficient level of receptor expression.

Topics: Amylases; Carcinoma, Acinar Cell; Cholecystokinin; Gastrins; Gene Expression Regulation, Neoplastic; Humans; In Situ Hybridization; Pancreatic Neoplasms; Receptors, Cholecystokinin; Reverse Transcriptase Polymerase Chain Reaction; Sincalide

Palliative operation plays an important part in the treatment of periampullary carcinoma. However, gastric bypass such as the widely practiced side-to-side gastrojejunostomy frequently fails to provide adequate drainage. Here we attempted to fashion an end-to-end duodenojejunostomy in the hope of establishing physiological continuity of the stomach and duodenum. Biliary bypass with side-to-side choledochojejunostomy is performed simultaneously. Eight patients underwent this surgery. In seven of these, radical resection proved to be impossible, and in one the duodeno-biliary decompression was attempted before the radical operation. Early results were satisfactory in all patients. They began to eat liquid meals within a week, and were discharged uneventfully within the third postoperative week, when they were able to eat a regular diet. No ulcer developed in any of the patients. Plasma gastrin levels following a test meal was significantly lower after the operation, but plasma CCK-N and GIP levels showed no statistical difference prior to and after surgery. This duodenojejunal bypass is recommended as a means of improving the quality of the remaining life of the patients.

Topics: Aged; Ampulla of Vater; Biliopancreatic Diversion; Choledochostomy; Common Bile Duct Neoplasms; Duodenostomy; Female; Gastric Emptying; Gastric Inhibitory Polypeptide; Gastrins; Gastrointestinal Transit; Humans; Jejunostomy; Male; Middle Aged; Palliative Care; Pancreatic Neoplasms; Postoperative Care; Sincalide; Survival Rate

Pancreatic cancer is a prevalent malignancy of the digestive system and a major cause of cancer-associated deaths. Previous studies have shown that mutation in the dermokine-β (DMKN-β) gene causes pancreatic and colorectal cancer. The role of the carboxy-terminal domain of DMKN-β and dermokine-α (DMKN-α) genes in cancer tumorigenesis. Herein, the role of DMKN-α in pancreatic cancer (PC) tumorigenesis and the mechanisms underlying this process were investigated. Differentially expressed genes between PC and matched normal cells were identified through RNA-seq analysis, and the corresponding protein expression levels were verified using Western blot analysis. In vivo tumor formation experiment was also performed in nude mice. We found that the DMKN-α gene was overexpressed in cancerous pancreatic cell lines compared to normal pancreatic cell lines. CCK-8, colony formation, RTCA test, wound healing, as well as transwell test showed that the overexpression of DMKN-α enhanced the proliferation, migration, invasion, and EMT of PC cells. In vivo assays confirmed that DMKN-α promotes tumorigenesis. The findings of this study show that DMKN-α is a potential oncogene for pancreatic cancer.

Topics: Animals; Carcinogenesis; Cell Line, Tumor; Cell Movement; Cell Proliferation; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic; Intercellular Signaling Peptides and Proteins; Mice; Mice, Nude; Neoplasm Invasiveness; Pancreatic Neoplasms; Sincalide

Pancreatic cancer belongs to lethal cancer with limited efficient treatment currently, and its main cause of death is rapid tumor growth and early metastasis. N6-methyladenosine (m6A) modification is a new method of epigenetic gene regulation involved in tumor progression, in which methyltransferase-like 3(METTL3) is the sole catalytic subunit. However, the role of METTL3 in pancreatic cancer remains to be explored.. m6A level was measured using MeRIP assay, and RT-qPCR and western blot were applied to determine mRNA and protein expression, respectively. Cellular behaviors were detected using CCK-8, EdU, wound healing and transwell assays. Xenograft assays were conducted to further verify the roles of METTL3 in pancreatic cancer.. METTL3 was highly expressed in pancreatic cancer. However, downregulation of METTL3 restrained the viability, migration and invasion of pancreatic cancer cells. Moreover, E2F5 was found to be positively regulated by METTL3. Intriguingly, the anti-tumor functions of METTL3 knockdown in the phenotype of pancreatic cancer cells were overturned by overexpression of E2F5. Silencing METTL3 resulted in the decreased stability of E2F5 by methylating E2F5.. In conclusion, METTL3 can promote the malignant progression of pancreatic cancer by modifying E2F5 through m6A methylation to promote its stability.

Topics: Adenosine; E2F5 Transcription Factor; Humans; Methyltransferases; Pancreatic Neoplasms; RNA, Messenger; Sincalide

It has been reported that signaling from the nerve growth factor (NGF) pathway associated with peripheral nerves is able to contribute to perineural invasion (PNI) of pancreatic cancer (PC). Nevertheless, the underlying mechanism by which NGF leads to PNI remained poorly understood.. Western blotting was employed to determine NGF level in PC and paracarcinoma tissues and in PC cell lines as well as pancreatic ductal epithelial cells. MiaPaCa-2 and CFPAC-1 cells were treated with 100 ng/ml of NGF or the NGF inhibitor Tanezumab for 24 h, CCK-8 and Transwell assays were employed to test cell proliferation, invasion, and migration, respectively. TrkA expression was knocked down in MiaPaCa-2 and dorsal root ganglion (DRG) cells treated with NGF to determine its effect on the Warburg effect. To reveal that the NGF-TrkA signaling pathway was closely associated with PC PNI,. NGF level was preeminently higher in PC tissues and cell lines than in paracarcinoma tissues and normal pancreatic epithelial cell lines. NGF promoted MiaPaCa-2 and CFPAC-1 cell invasion and migration, while Tanezumab treatment showed the opposite results. Besides, NGF binding to TrkA receptors encouraged the intracellular Warburg effect in PC and DRG cells. TrkA blocking-up could restrain NGF induced PC cell migration and neural invasion. Mechanistically, NGF could upregulate TDE-miR-21-5p levels, and DRG cells took up TDE to activate the Warburg effect and stimulate nociceptor gene expression. miR-21-5p inhibitor could abolish the facilitative effect of NGF on PNI in MiaPaCa-2 cells.. These findings displayed that NGF/TrkA encouraged the neuroinvasive potential of PC cells by activating the Warburg effect in DRG cells through upregulation of TDE-miR-21-5p expression.

Topics: Animals; Cell Line, Tumor; Cell Proliferation; Gene Expression Regulation, Neoplastic; Mice; Mice, Nude; MicroRNAs; Neoplasm Invasiveness; Nerve Growth Factor; Pancreatic Neoplasms; Sincalide

OATP1B3 is a member of the OATP (organic anion transporting polypeptides) superfamily, responsible for mediating the transport of numerous endogenous and xenobiotic substances. Although initially reported to be exclusively expressed in the liver, several studies reported that OATP1B3 is frequently expressed in multiple types of cancers and may be associated with differing clinical outcomes. However, a detailed investigation on the expression and function of OATP1B3 protein in cancer has been lacking. In this study, we confirmed that colon and pancreatic cancer cells express variant forms of OATP1B3, different from OATP1B3 wild-type (WT) expressed in the normal liver. OATP1B3 variant 1 (V1), the most prevalent form among the variants, contains alternative exonic sequences (exon 2a) instead of exons 1 and 2 present in OATP1B3 WT. The translated product of OATP1B3 V1 is almost identical to OATP1B3 WT, with exception to the first 28 amino acids at the N-terminus. Exogenous expression of OATP1B3 V1 revealed that OATP1B3 V1 undergoes post-translational modifications and proteasomal degradation to a differing extent compared to OATP1B3 WT. OATP1B3 V1 showed only modest transport activity toward cholecystokin-8 (CCK-8, a prototype OATP1B3 substrate) in contrast to OATP1B3 WT showing a markedly efficient uptake of CCK-8. Consistent with these results, OATP1B3 V1 was localized mainly in the cytoplasm with a much lower extent of trafficking to the surface membrane compared to OATP1B3 WT. In summary, our results demonstrate that colon and pancreatic cancer cells express variant forms of OATP1B3 with only limited transport activity and different subcellular localization compared to OATP1B3 WT. These observed differences at the molecular and functional levels will be important considerations for further investigations of the biological and clinical significance of OATP1B3 expression in cancer.

Topics: Biological Transport; Cell Line, Tumor; Colonic Neoplasms; Cytoplasm; Exons; Genetic Variation; HCT116 Cells; Humans; Liver; Organic Anion Transporters, Sodium-Independent; Pancreatic Neoplasms; Protein Processing, Post-Translational; Sincalide; Solute Carrier Organic Anion Transporter Family Member 1B3

Resveratrol (3,4',5-trihydroxy-trans-stilbene), a phytoalexin naturally found in grapes and red wine, is a redox-active compound endowed with significant positive activities. In this study, the effects of resveratrol on intracellular free Ca(2+) concentration ([Ca(2+)](c)) and on cell viability in tumoral AR42J pancreatic cells are examined. The results show that resveratrol (100 μM and 1 mM) induced changes in [Ca(2+)](c), that consisted of single or short lasting spikes followed by a slow reduction toward a value close to the resting level. Lower concentrations of resveratrol (1 and 10 μM) did not show detectable effects on [Ca(2+)](c). Depletion of intracellular Ca(2+) stores by stimulation of cells with 1 nM CCK-8, 20 pM CCK-8 or 1 μM thapsigargin, blocked Ca(2+) responses evoked by resveratrol. Conversely, prior stimulation of cells with resveratrol inhibited Ca(2+) mobilization in response to a secondary application of CCK-8 or thapsigargin. In addition, resveratrol inhibited oscillations in [Ca(2+)](c) evoked by a physiological concentration of CCK-8 (20 pM). On the other hand, incubation of cells in the presence of resveratrol induced a reduction of cell viability. Finally, incubation of AR42J cells in the presence of resveratrol led to activation of c-Jun N-terminal kinase (JNK), a mitogen-activated protein kinase responsive to stress stimuli. Activation of JNK was reduced in the absence of extracellular Ca(2+). In summary, the results show that resveratrol releases Ca(2+) from intracellular stores, most probably from the endoplasmic reticulum, and reduces AR42J cells viability. Reorganization of cell's survival/death processes in the presence of resveratrol may involve Ca(2+)-mediated JNK activation.

Topics: Animals; Antioxidants; Calcium; Cell Line, Tumor; Cell Survival; Endoplasmic Reticulum; JNK Mitogen-Activated Protein Kinases; MAP Kinase Signaling System; Pancreatic Neoplasms; Rats; Resveratrol; Sincalide; Stilbenes; Thapsigargin

Genetic mutations that give rise to active mutant forms of Ras are oncogenic and found in several types of tumor. However, such mutations are not clear biomarkers for disease, since they are frequently detected in healthy individuals. Instead, it has become clear that elevated levels of Ras activity are critical for Ras-induced tumorigenesis. However, the mechanisms underlying the production of pathological levels of Ras activity are unclear. Here, we show that in the presence of oncogenic Ras, inflammatory stimuli initiate a positive feedback loop involving NF-κB that further amplifies Ras activity to pathological levels. Stimulation of Ras signaling by typical inflammatory stimuli was transient and had no long-term sequelae in wild-type mice. In contrast, these stimuli generated prolonged Ras signaling and led to chronic inflammation and precancerous pancreatic lesions (PanINs) in mice expressing physiological levels of oncogenic K-Ras. These effects of inflammatory stimuli were disrupted by deletion of inhibitor of NF-κB kinase 2 (IKK2) or inhibition of Cox-2. Likewise, expression of active IKK2 or Cox-2 or treatment with LPS generated chronic inflammation and PanINs only in mice expressing oncogenic K-Ras. The data support the hypothesis that in the presence of oncogenic Ras, inflammatory stimuli trigger an NF-κB-mediated positive feedback mechanism involving Cox-2 that amplifies Ras activity to pathological levels. Because a large proportion of the adult human population possesses Ras mutations in tissues including colon, pancreas, and lung, disruption of this positive feedback loop may be an important strategy for cancer prevention.

Topics: Animals; Carcinoma, Pancreatic Ductal; Cell Transformation, Neoplastic; Ceruletide; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Enzyme Induction; Esters; Feedback, Physiological; Gabexate; Gene Expression Regulation, Neoplastic; Gene Knock-In Techniques; Genes, ras; Guanidines; Humans; I-kappa B Kinase; Inflammation; Inflammation Mediators; Lipopolysaccharides; Mice; Mice, Transgenic; Neoplasm Proteins; NF-kappa B; Pancreas; Pancreatic Neoplasms; Pancreatitis, Chronic; Precancerous Conditions; Proto-Oncogene Proteins p21(ras); Sincalide

The aim of the present study was to investigate the possible interaction between intracellular Ca(2+) and nitric oxide (NO) in rat pancreatic acinar cells, especially intracellular signaling events. (1) Nitric oxide donors SNP (0.1-100 μM) and NOR-3 (50-400 μM) induced Ca(2+) oscillations in fluo-4-loaded acini, that appeared to be analogous to what we usually observe in acini stimulated with physiological secretagogues such as CCK-8 and this oscillations were abolished in the presence of carboxy-PTIO. (2) The NO donors-evoked Ca(2+) oscillations were not abolished even in the absence of extracellular Ca(2+) but totally disappeared when cells were pretreated with thapsigargin, a sarcoplasmic-endoplasmic reticulum Ca(2+) ATPase (SERCA) inhibitor. (3) Inhibition of guanylate cyclase with 1 H-[1,2,4] oxadiazolo [4,3-a] quinoxaline-1-one (ODQ) attenuated Ca(2+) oscillations evoked by SNP in the absence of extracellular Ca(2+). (4) Inhibitors of phospholipase C activity, U73122 and the IP(3)R blocker xestospongin C, both abolished the SNP-induced Ca(2+) response. (5) Furthermore, we found that both CCK-8 and carbachol (CCh) induced NO production in DAF-2-loaded acinar cells and that an inhibitor of NO synthase, N(G)-monomethyl-l-arginine (L-NMMA), significantly reduced CCK-8-induced Ca(2+) oscillation. These results indicate that NO mobilizes Ca(2+) from internal stores through activation of guanylate cyclase and resultant cGMP production. In addition, PLC activation of IP(3) production is also suggested to be involved in Ca(2+) mobilization via IP(3) receptors. This suggests the presence of cross-talk between Ca(2+) and NO in pancreatic acini and this cascade may, at least partially, participate in physiological secretagogue-evoked Ca(2+) dynamics in pancreatic acinar cells.

Topics: Animals; Calcium; Carcinoma, Acinar Cell; Estrenes; Inositol 1,4,5-Trisphosphate; Macrocyclic Compounds; Male; Nitric Oxide; Nitric Oxide Donors; Nitroprusside; Oxadiazoles; Oxazoles; Pancreatic Neoplasms; Phosphodiesterase Inhibitors; Pyrrolidinones; Quinoxalines; Rats; Rats, Wistar; Signal Transduction; Sincalide; Type C Phospholipases

Z-360 is an orally active cholecystokinin-2 (CCK2)/gastrin receptor antagonist currently under development as a therapeutic drug for pancreatic cancer. It was previously reported that Z-360 treatment in combination with gemcitabine prolonged the survival period in a lethal pancreatic cancer xenograft model in mice. In a phase Ib/IIa clinical study, Z-360 treatment displayed a trend of reduced pain in patients with advanced pancreatic cancer in combination with gemcitabine including analgesics such as opioids. Here, we investigated the mechanism of analgesic action of Z-360 in a severe cancer-induced pain model in mice, which is considered to be opioid-resistant, by examining ephrin B1 gene expression, N-methyl-D-aspartate receptor NR2B subunit phosphorylation, and interleukin-1β (IL-1β) production.. In a mouse model of cancer-induced pain, ephrin B1 gene expression in dorsal root ganglia (DRGs) and the phosphorylation of NR2B in the spinal cord were induced. Z-360 treatment inhibited both ephrin B1 gene expression and the phosphorylation of NR2B. In addition, IL-1β production increased in the cancer-inoculated hind paw of mice, but could be suppressed by treatment with Z-360. Moreover, we observed that the CCK1 receptor antagonist devazepide similarly suppressed up-regulation of ephrin B1 gene expression and IL-1β production, and that the intraperitoneal injection of sulfated CCK-8 induced the production of IL-1β in the cancer-inoculated region.. We have identified a novel pain cascade, in which IL-1β production in cancer-inoculated regions induces ephrin B1 gene expression in DRGs and then ephrin B1 enhances the tyrosine phosphorylation of NR2B via Eph B receptor in the spinal cord. Notably, Z-360 relieves cancer-induced pain by preventing this pain cascade through the suppression of IL-1β production, likely via the blockade of CCK1 receptor. The pre-clinical results presented here support the analgesic action of Z-360 in pancreatic cancer patients with severe, opioid-resistant pain. Pre-clinical and clinical results have demonstrated that Z-360 combined with gemcitabine represents a promising pancreatic cancer therapy approach with characteristic analgesic effects in addition to the prolongation of survival.

Topics: Animals; Benzodiazepinones; Cell Line, Tumor; Devazepide; Disease Models, Animal; Ephrin-B1; Extremities; Ganglia, Spinal; Gene Expression Regulation, Neoplastic; Injections; Interleukin-1beta; Mice; Pain; Pancreatic Neoplasms; Phosphorylation; Receptors, Eph Family; Receptors, N-Methyl-D-Aspartate; Sincalide; Up-Regulation

Akt is a central regulator of apoptosis, cell growth and survival. Growth factors and some G-protein-coupled receptors (GPCR) regulate Akt. Whereas growth-factor activation of Akt has been extensively studied, the regulation of Akt by GPCR's, especially gastrointestinal hormones/neurotransmitters, remains unclear. To address this area, in this study the effects of GI growth factors and hormones/neurotransmitters were investigated in rat pancreatic acinar cells which are high responsive to these agents. Pancreatic acini expressed Akt and 5 of 7 known pancreatic growth-factors stimulate Akt phosphorylation (T308, S473) and translocation. These effects are mediated by p85 phosphorylation and activation of PI3K. GI hormones increasing intracellular cAMP had similar effects. However, GI-hormones/neurotransmitters [CCK, bombesin, carbachol] activating phospholipase C (PLC) inhibited basal and growth-factor-stimulated Akt activation. Detailed studies with CCK, which has both physiological and pathophysiological effects on pancreatic acinar cells at different concentrations, demonstrated CCK has a biphasic effect: at low concentrations (pM) stimulating Akt by a Src-dependent mechanism and at higher concentrations (nM) inhibited basal and stimulated Akt translocation, phosphorylation and activation, by de-phosphorylating p85 resulting in decreasing PI3K activity. This effect required activation of both limbs of the PLC-pathway and a protein tyrosine phosphatase, but was not mediated by p44/42 MAPK, Src or activation of a serine phosphatase. Akt inhibition by CCK was also found in vivo and in Panc-1 cancer cells where it inhibited serum-mediated rescue from apoptosis. These results demonstrate that GI growth factors as well as gastrointestinal hormones/neurotransmitters with different cellular basis of action can all regulate Akt phosphorylation in pancreatic acinar cells. This regulation is complex with phospholipase C agents such as CCK, because both stimulatory and inhibitory effects can be seen, which are mediated by different mechanisms.

Topics: Animals; Calcium; Cell Line, Tumor; Cyclic AMP; Enzyme Activation; Enzyme Inhibitors; Gastrointestinal Hormones; Intercellular Signaling Peptides and Proteins; Male; Neurotransmitter Agents; Pancreas; Pancreatic Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinase C; Protein Processing, Post-Translational; Protein Transport; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Receptor, Cholecystokinin A; Signal Transduction; Sincalide; src-Family Kinases; Type C Phospholipases

The peptide hormone cholecystokinin (CCK) plays an important role in the gastrointestinal tract. The rat pancreatic CCK receptor is a highly glycosylated membrane receptor that is able to bind to plant lectins such as wheat germ agglutinin (WGA) and Ulex europaeus agglutinin (UEA-I).. We used both lectins to block this receptor for studying the pathophysiologic relevance of its oligosaccharide side chains. In the present study we investigated the influence of WGA and UEA-I on CCK-8-induced alpha-amylase secretion of the rat pancreatic tumor cell line AR42J, which expresses both CCK-A and CCK-B receptors.. Under the influence of WGA (25 microg/mL), the alpha-amylase release was reduced by 25% after 30 minutes compared with the hormone-stimulated controls. UEA-I (25 microg/mL) caused a reduction of 20%. The simultaneous application of the lectins with CCK antagonists L 364,718 or L 365,260 led to a reduction of secretion, but the assignment to CCK-A or CCK-B receptors was not possible.. In long-term studies, both lectins revealed no toxic or apoptosis-inducing effects. On the contrary, WGA showed an inhibitory effect on cell proliferation and led to improved differentiation of cells.

Topics: alpha-Amylases; Animals; Benzodiazepinones; Cell Differentiation; Cell Division; Devazepide; Kinetics; Lectins; Microscopy, Electron; Pancreas; Pancreatic Neoplasms; Phenylurea Compounds; Plant Lectins; Rats; Receptor, Cholecystokinin A; Receptor, Cholecystokinin B; Receptors, Cholecystokinin; Sincalide; Tumor Cells, Cultured; Wheat Germ Agglutinins

We have previously reported that cholecystokinin (CCK) plays an important role in the invasiveness and the production of matrix metalloproteinase-9 (MMP-9) in two human pancreatic cancer cell lines. In this study we investigated the pathway of the invasiveness associated with MMP-9 of those lines regulated by CCK. Two human pancreatic cancer cell lines were treated with CCK-8 alone, CCK-8 and staurosporine, or CCK-8 and indomethacine. The invasiveness and the production of MMP-9 were decreased with staurosporine but not indomethacine. These results suggest that CCK may regulate the invasiveness and the production of MMP-9 via protein kinase C in human pancreatic cancer cell lines.

Topics: Blotting, Western; Cholecystokinin; Collagenases; Cyclooxygenase Inhibitors; Dinoprostone; Dopamine Agents; Enzyme Induction; Enzyme Inhibitors; Humans; Immunoenzyme Techniques; Indomethacin; Matrix Metalloproteinase 9; Neoplasm Invasiveness; Pancreatic Neoplasms; Protein Kinase C; Signal Transduction; Sincalide; Staurosporine; Tumor Cells, Cultured

Growth of the human pancreatic carcinoma cell line KP-1N was stimulated with cholecystokinin (CCK)-8. A 40% increase in cell numbers was observed in the presence of 10(-10) MCCK-8 and this increase was inhibited by the addition of 25 microM CCK-A receptor antagonist (CR1505). The binding affinity of CCK-8 to KP-1N cells was 21-fold higher than that of gastrin 17-I. No significant increase in intracellular Ca2+ concentration was found upon stimulation with CCK-8. Components of signal transduction pathways that were activated in KP-1N cells after stimulation with CCK-8 were studied. CCK-8 stimulated tyrosine phosphorylation of a mitogen-activated protein kinase (MAPK) of approximately 42 kDa (p42map). c-Jun amino-terminal kinases (JNKs) of 46 kDa (p46jnk) and 55 kDa (p55jnk) were also activated by CCK-8 and increased the phosphorylation of c-Jun. CCK-8 at 10(-7) M induced 1.5-fold increases in the phosphorylation of MAPK and of c-Jun by JNKs, respectively. These results suggest that cell proliferation stimulated with CCK-8 in KP-1N cells may be mediated by signal transduction cascades leading to activation of JNKs and MAPKs.

Topics: Calcium-Calmodulin-Dependent Protein Kinases; Carcinoma, Ductal, Breast; Cell Division; Enzyme Activation; Humans; JNK Mitogen-Activated Protein Kinases; MAP Kinase Kinase 4; Mitogen-Activated Protein Kinase Kinases; Pancreatic Neoplasms; Protein Kinases; Signal Transduction; Sincalide; Tumor Cells, Cultured

To investigate the effects of increasing concentrations of cholecystokinin octapeptide (CCK-8) on a pancreatic acinar adenocarcinoma.. Growth of the tumour was estimated in vivo on rats bearing a subcutaneous pancreatic carcinoma, and in vitro on primary cultured tumour cells. CCK receptors were characterized by binding assays.. CCK-8, administered for 12 successive days, exerted a biphasic action on tumour growth: a dose-dependent stimulation with low doses (0.1 and 0.5 microg/kg) and inhibition with high doses (2 and 4 microg/ kg) as shown by respective increases and decreases in tumor volume, protein, RNA and amylase contents. In cell cultures, [3H]thymidine incorporation was dose-dependently increased with 10-(10) to 10(-8) M CCK-8 and inhibited with 10(-7) M. Both effects were completely suppressed by the CCK-receptor antagonists CR 1409 and L 364,718 (10(-4) M). Binding studies showed the overexpression of two classes of CCK-A receptors of low and high affinity when compared to the normal pancreas which was less sensitive to CCK-8.. CCK-8 exerts a biphasic growth response on the acinar pancreatic carcinoma, mediated by two classes of CCK-A receptors overexpressed in the tumour.

Topics: Animals; Azaserine; Carcinoma, Acinar Cell; Cell Division; Dose-Response Relationship, Drug; Iodine Radioisotopes; Pancreatic Neoplasms; Radioligand Assay; Rats; Rats, Inbred Lew; Receptors, Cholecystokinin; Sincalide; Tumor Cells, Cultured

Cholecystokinin (CCK) acting via CCK(A) receptors and gastrin acting via CCK(B) receptors exert trophic effects on a variety of nontransformed tissues. However, their role as hormonal regulators of pancreatic cancer is controversial. The aim of this study was to determine the effects of activation of CCK(A) and CCK(B) receptors on the growth of human pancreatic cancer cells in vitro.. Two human pancreatic cell lines MiaPaca-2 and Panc-1 were transfected stably with both CCK receptor subtypes. Effects of CCK on various growth parameters including DNA synthesis, nuclear labeling, and colony formation were evaluated.. Cells expressing either receptor subtype, but not untransfected cells, bound ligand and mobilized Ca2+ in response to CCK. CCK treatment caused a sustained pronounced inhibition of anchorage-independent growth. Similarly, CCK treatment inhibited anchorage-dependent growth. Receptor activation caused a concentration and time-dependent reduction in [3H]thymidine incorporation and nuclear labeling in cells cultured anchored to a plastic substrate. However, these effects on anchorage-dependent growth were transient, suggesting cellular desensitization.. These data indicate that both CCK receptor subtypes can mediate growth inhibitory responses in pancreatic cancer cell lines and raise the possibility that CCK exerts a predominant growth inhibitory action on human pancreatic cancer cells.

Topics: Cell Division; DNA; Dose-Response Relationship, Drug; Humans; Pancreatic Neoplasms; Receptors, Cholecystokinin; Sincalide; Tumor Cells, Cultured

Several immortalized cell lines serve as models for procholecystokinin (pro-CCK) processing. Rin5F cells, derived from a rat insulinoma, and STC-1 cells, derived from a murine intestinal tumor, process pro-CCK mainly to amidated CCK 8. Both also make significant quantities of amidated CCK 22, a slightly larger form found in the gut. Many modifications are necessary during pro-CCK processing including cleavages performed by endoproteases, the identities of which are unknown. A candidate endoprotease is prohormone convertase 1 (PC1) also known as PC3, a Ca2+-dependent serine endoprotease of the subtilisin family. Constitutive expression of antisense PC1 message in stably transfected Rin5F cells resulted in a significant reduction of the cellular content of CCK 8 as measured by radioimmunoassay. Several affected cell lines displayed about 80% reduction in CCK content in early passages after transfection. Expression of antisense PC1 message in these cell lines resulted in a selective depletion of CCK 8 and a comparative sparing of CCK 22. The induction of antisense PC1 message within a single subclone of Rin5F cells using the Lac Switch system also resulted in a significant inhibition of CCK content. Expression of antisense PC1 message in a stably transfected STC-1 cell line also resulted in a decrease in CCK content and in PC1 protein expression, and the specific depletion of CCK 8 with comparative sparing of CCK 22. These observations support the hypothesis that PC1 is necessary for pro-CCK processing in Rin5F and STC-1 cells and suggests a role for PC1 endoprotease in the biosynthesis of CCK 8 in vivo.

Topics: Animals; Aspartic Acid Endopeptidases; Cholecystokinin; Chromatography, Gel; Insulinoma; Intestinal Neoplasms; Models, Chemical; Oligonucleotides, Antisense; Pancreatic Neoplasms; Peptide Fragments; Proprotein Convertases; Rats; Sincalide; Tumor Cells, Cultured

Gut hormones that modulate the growth of normal pancreas may also modulate the growth of cancers originating from pancreas. This study visualized and compared the receptors for cholecystokinin (CCK), bombesin (BBS), secretin and vasoactive intestinal peptide (VIP) in tumour-free tissue sections of human pancreas (n = 10) and pancreatic ductal adenocarcinomas (n = 12) with storage phosphor autoradiography using radioligands. CCK-B receptors, present in control pancreata, were not detected in any of the pancreatic cancers. BBS receptors were visualized in control pancreata, but they were absent in 10 of 12 pancreatic cancers. In 5 of 12 pancreatic cancers, receptors for secretin were visualized, while binding for secretin was present in all tumour-free pancreata. Conversely, no specific binding of VIP was detected in control pancreata but was identified in 3 of 12 pancreatic cancer specimens. It is concluded that the expression of gut peptide receptors in pancreatic cancer differs from that in tumour-free pancreas. Receptors for these peptides are present in only a minority of pancreatic cancer specimens.

Topics: Adenocarcinoma; Adult; Aged; Autoradiography; Bombesin; Female; Humans; Iodine Radioisotopes; Kinetics; Male; Middle Aged; Pancreas; Pancreatic Neoplasms; Receptors, Bombesin; Receptors, Cholecystokinin; Receptors, G-Protein-Coupled; Receptors, Gastrointestinal Hormone; Receptors, Vasoactive Intestinal Peptide; Secretin; Sensitivity and Specificity; Sincalide; Succinimides

Two endocrine tumor cell lines from pancreas (RIN5F) and intestine (STC-1) express cholecystokinin (CCK) messenger RNA and are able to posttranslationally process pro-CCK to CCK-22 and CCK-8 amide. Both of these forms are also secreted by these cells. Because they make and secrete forms of amidated CCK larger than CCK-8, they represent a model of pro-CCK processing in the gut and allow investigation of possible mechanisms for tissue differences in prohormone processing. Both of these cells express two endoproteases convertase-1 (PC1) also known as PC3 and prohormone convertase-2 (PC2), which may be involved in pro-CCK processing. We have previously shown than inhibition of PC1 expression in these cells using stable expression of antisense messenger RNA caused a significant reduction in cellular content of amidated CCK and caused a selective depletion of CCK-8 with a comparative sparing of CCK-22. We demonstrate here that inhibition of PC2 expression in these cells also caused a large initial decrease in CCK content and produced a selective depletion of CCK-22 and a comparative sparing of CCK-8. These results support both a role for both PC1 and PC2 in pro-CCK processing in these cells and the hypothesis that tissue-specific processing of pro-CCK may be explained by differences in expression or activity of PC1 and PC2.

Topics: Cholecystokinin; Gene Expression; Intestinal Neoplasms; Pancreatic Neoplasms; Peptide Fragments; Proprotein Convertase 2; RNA, Antisense; RNA, Messenger; Sincalide; Subtilisins; Transfection; Tumor Cells, Cultured

It was recently found that cholecystokinin (CCK) activates mitogen-activated protein kinases (MAPK) in isolated rat pancreatic acini. The present study evaluates whether one or both types of CCK receptors are capable of MAPK activation in pancreatic AR42J acinar cells as well as CHO cells transfected with CCK-A or CCK-B receptors. CCK significantly increased p44 MAPK and p42 MAPK activities in AR42J cells. Minimal, half-maximal, and maximal responses were observed at 30 and 500 pM and 10 nM, respectively, after CCK-8 stimulation and at 100 pM and 1.5 and 30 nM, respectively, after gastrin stimulation. Glycine-extended gastrin had no effect at 100 nM and a small but significant effect at 1 microM. The CCK-B receptor antagonist L365,260 almost totally blocked MAPK activation in AR42J cells after stimulation with gastrin and glycine-extended gastrin and substantially reduced the activation of both kinases by CCK-8, while the CCK-A receptor antagonist L364,718 was much less effective. The CCK-A-selective agonist A71376, however, was an effective stimulant of MAPK activity. In an alternative approach, stably transfected CHO cells bearing either CCK-A or CCK-B receptors were stimulated with CCK-8. Each receptor induced a time-dependent increase in activity of both MAPKs by five- to sixfold in CCK-A- and CCK-B-bearing cells. In conclusion, both CCK-A and CCK-B receptors activate MAPK in AR42J cells and in transfected CHO cells.

Topics: Animals; Benzodiazepinones; Blotting, Western; Carcinoma, Acinar Cell; Cells, Cultured; CHO Cells; Cricetinae; Devazepide; Dose-Response Relationship, Drug; Gastrins; MAP Kinase Kinase Kinase 4; MAP Kinase Kinase Kinases; Oligopeptides; Pancreatic Neoplasms; Phenylurea Compounds; Protein Kinases; Rats; Receptor, Cholecystokinin A; Receptor, Cholecystokinin B; Receptors, Cholecystokinin; Reference Values; Sincalide; Transfection; Tumor Cells, Cultured

Cholecystokinin (CCK) is known to stimulate pancreatic cancer cell growth, but no detailed CCK receptor subtype characterization and investigation of CCK receptor-mediated cellular responses in human pancreatic cancer cells have been reported thus far. In this study, CCK binding sites were identified in human pancreatic cancer cells (MIA-PaCa-2) using radioligand binding studies. Pharmacological characterization demonstrated a single class of high-affinity CCK sites on MIA-PaCa-2 cells (326 +/- 18 pM, receptor density 16.9 +/- 2.3 fmol/mg protein). These CCK binding sites displayed a typical CCKB binding profile as shown in competition studies by using different CCK-related compounds and non-peptide CCK antagonists discriminating between CCKA and CCKB sites. CCKB receptor-connected effector systems have been characterized in MIA-PaCA-2 cells, and their involvement in CCK-8S-induced proliferative effects on MIA-PaCa-2 cells has been demonstrated.

Topics: Calcium; Cell Division; Humans; Inositol 1,4,5-Trisphosphate; Iodine Radioisotopes; Pancreatic Neoplasms; Protein Kinase C; Radioligand Assay; Receptor, Cholecystokinin B; Receptors, Cholecystokinin; Signal Transduction; Sincalide; Thymidine; Tritium; Tumor Cells, Cultured

The peptide hormone cholecystokinin (CCK) has been shown to stimulate the growth of azaserine-induced preneoplastic nodules in the rat pancreas. Previously, our labortory demonstrated by classical binding studies that CCK receptors are overexpressed in azaserine-induced rat pancreatic neoplasms. In the present study, we utilized autoradiography to determine the temporal course of this increased receptor binding. Male Lewis rats were given azaserine or saline injections and sacrificed at 2, 4, 8, 12, and 18 months of age. Pancreatic tissue was harvested and autoradiography using 125l-labeled. CCK-8 was performed. Densitometry measurements of azaserine-induced pancreatic nodules, internodular pancreas, and normal pancreatic tissue (from saline-treated controls) of each age group were taken with an image analyzer. There was no statistically significant difference in CCK binding to internodular pancreas and normal pancreas at any age. At 2 months of age, there was no significant increase in CCK binding to azaserine-induced pancreatic nodules. However, at 4, 8, 12, and 18 months of age there was significantly greater CCK binding to azaserine-induced pancreatic nodules than to both internodular pancreas and normal pancreas (p < 0.001 for all groups). At 18 months of age, one azaserine-treated animal developed a pancreatic acinar cell carcinoma, which likewise exhibited significantly greater CCK binding than internodular pancreas or normal pancreas (p < 0.001 for both). These findings demonstrate increased CCK binding in azaserine-induced preneoplastic pancreatic nodules and pancreatic acinar cell carcinoma, compatible with our previous demonstration of receptor overexpression in these tissues. Increased CCK binding first becomes apparent by 4 months following exposure to azaserine. These result suggest that overexpression of CCK receptors, located specifically on preneoplastic and neoplastic pancreatic lesions, results in increased CCK binding and is involved in the mediation of CCK-stimulated growth during azaserine-induced pancreatic carcinogenesis.

Topics: Animals; Autoradiography; Azaserine; Densitometry; Iodine Radioisotopes; Male; Pancreatic Neoplasms; Rats; Rats, Inbred Lew; Receptors, Cholecystokinin; Sincalide

Recently, cholecystokinin has been reported to be important in regulating the growth of pancreatic cancer. We investigated the effect of loxiglumide (LXG), a cholecystokinin receptor antagonist, on the invasiveness of two human pancreatic cancer cell lines. Cells were treated with LXG for 24 h, and examined in the invasion assay. The expression and activity of MMP-9 in supernatants from cancer cells were analyzed by Western blotting and zymogram. Interestingly, the invasiveness of cancer cells and expression of MMP-9 were decreased by LXG in a dose-dependent manner. LXG may be a useful therapeutic agent against pancreatic cancer.

Topics: Blotting, Western; Cell Line; Collagenases; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Gelatin; Hormone Antagonists; Humans; Kinetics; Matrix Metalloproteinase 9; Neoplasm Invasiveness; Pancreatic Neoplasms; Proglumide; Sincalide; Tumor Cells, Cultured

It has been previously demonstrated that guinea pig pancreas possesses both cholecystokinin-A (CCK-A) receptors and CCK-B (gastrin) receptors. In contrast to guinea pig pancreas, it is not known whether CCK receptors in rat pancreas are CCK-A receptors, CCK-B (gastrin) receptors, or both. Thus, in the present study, we characterized CCK receptors in rat pancreas at the receptor and mRNA level. 125I-Bolton-Hunter-labeled CCK octapeptide (125I-BH-CCK-8), the specific CCK-A and CCK-B (gastrin) receptor antagonists L364,718 and L365,260, and 125I-labeled gastrin-I were utilized to characterize CCK receptors in normal rat pancreas. Additionally, we utilized 32P-labeled cDNA probes of the CCK-A receptor and CCK-B (gastrin) receptor coding regions in order to examine the expression of CCK receptor subtypes in normal rat pancreas at the mRNA level. The dose-inhibition curve of CCK-8 inhibiting binding of 125I-BH-CCK-8 was significantly best fit by a two-site model with a high-affinity site (Kd = 0.68 +/- 0.13 nM) and a low-affinity site (Kd = 656 +/- 289 nM). L364,718 inhibited binding of 125I-BH-CCK-8 with high affinity, whereas no high-affinity inhibition for L365,260 to inhibit binding of 125I-BH-CCK-8 was detected. L364,718 was 627 times as potent as L365,260 in inhibiting binding of 125I-BH-CCK-8. No saturable binding was present for 125I-labeled gastrin-I. Gastrin-17-I did not inhibit binding of 125I-BH-CCK-8.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Base Sequence; Blotting, Northern; Gene Expression; Male; Molecular Sequence Data; Pancreas; Pancreatic Neoplasms; Polymerase Chain Reaction; Rats; Rats, Inbred Lew; Receptor, Cholecystokinin A; Receptor, Cholecystokinin B; Receptors, Cholecystokinin; RNA-Directed DNA Polymerase; RNA, Messenger; Sincalide; Succinimides; Tumor Cells, Cultured

Important differences exist in the responses to photodynamic agents of normal and tumour-derived pancreatic acinar cells. In the present study amylase release has been used to assess the mechanisms by which the photodynamic drugs tetra- and disulphonated aluminium phthalocyanine (A1PcS4, A1PcS2) act on pancreatic cells via energy and calcium-dependent activation and transduction pathways. The photodynamic release of amylase was found to be energy dependent and inhibited by the chelation of free cytoplasmic calcium but not by the removal of extracellular calcium. In contrast to their effects on normal acinar cells, the photodynamic action of A1PcS4 and A1PcS2 was to inhibit amylase secretion from pancreatoma AR4-2J cells. Removal of extracellular calcium reversed this inhibitory effect on AR4-2J cells and produced a significant increase in amylase release, but chelation of free cytoplasmic calcium did not affect the inhibitory photodynamic action of the phthalocyanines on amylase release from the tumour cells. Overall, these results demonstrate further important distinctions between the photodynamic action of sulphonated aluminium phthalocyanines on normal versus tumour exocrine cells of the pancreas and indicate that calcium plays an important role in photodynamic drug action, since these agents affected intracellular calcium mobilisation at some distal point in the membrane signal transduction pathway for regulated secretion. Furthermore, the photodynamic inhibition of constitutive secretion in tumour cells may involve a calcium-dependent membrane target site or modulation of membrane calcium channels by activation of protein kinase C.

Topics: Amylases; Animals; Antimycin A; Bethanechol; Calcium; Carcinoma, Acinar Cell; Deoxyglucose; Egtazic Acid; Indoles; Male; Oligomycins; Organometallic Compounds; Pancreas; Pancreatic Neoplasms; Photochemotherapy; Radiation-Sensitizing Agents; Rats; Rats, Sprague-Dawley; Signal Transduction; Sincalide; Stimulation, Chemical; Tumor Cells, Cultured

Transgenic mice bearing the rat elastase I promoter - SV40 T-antigen (ELSV) fusion gene develop pancreatic acinar cell carcinomas by 3-6 months of age. In other animal models of pancreatic cancer, cholecystokinin (CCK) has been shown to be a tumor promoter. Therefore, we characterized CCK binding properties and CCK-A receptor mRNA expression in pancreatic carcinomas and dysplastic pancreata from the Tg(Ela-1, SV40E+Ela-1, neo)Bri19 strain of ELSV transgenic mice. To accomplish this, we utilized 125I-Bolton-Hunter-labeled-cholecystokinin octapeptide (125I-BH-CCK-8) binding studies, reverse transcription-polymerase chain reaction (RT-PCR), and Southern blot analysis to examine pancreatic carcinomas from 26-week-old male ELSV transgenic mice, dysplastic pancreata from 8-week-old male ELSV transgenic mice, and normal pancreas from 30-week-old nontransgenic male mice (SJL/J) and 8-week-old nontransgenic male mice (B6SJLF1/J). Optimal saturable CCK-8 binding was detected at pH 6.5, 22 degrees C. Competitive inhibition 125I-BH-CCK-8 binding assays performed on all four mouse pancreatic tissues showed that CCK-8 bound to two classes of CCK binding sites: a high affinity, lower capacity CCK binding site and a low affinity, higher capacity CCK binding site. RT-PCR and Southern blot analysis confirmed the 125I-BH-CCK-8 binding studies by demonstrating CCK-A receptor mRNA expression in the ELSV transgenic pancreatic carcinomas and dysplastic pancreas, as well as in normal nontransgenic mouse pancreas. In conclusion, pancreatic carcinomas and dysplastic pancreas from ELSV transgenic mice and normal nontransgenic mouse pancreas all bind 125I-BH-CCK-8 and express mRNA for the CCK-A receptor. In contrast to chemically-induced pancreatic tumors in the rat, ELSV transgenic mouse pancreatic tumors do not appear to significantly overexpress CCK-A receptors.

Topics: Animals; Antigens, Polyomavirus Transforming; Base Sequence; Binding, Competitive; Blotting, Southern; Carcinoma, Acinar Cell; Indicators and Reagents; Iodine Radioisotopes; Male; Mice; Mice, Transgenic; Molecular Sequence Data; Pancreas; Pancreatic Elastase; Pancreatic Neoplasms; Polymerase Chain Reaction; Promoter Regions, Genetic; Rats; Receptor, Cholecystokinin A; Receptors, Cholecystokinin; Recombinant Fusion Proteins; RNA, Messenger; Sincalide; Succinimides; Transcription, Genetic

Topics: Animals; Azaserine; Carcinogens; Cell Division; Cholecystokinin; Male; Pancreas; Pancreatic Neoplasms; Peptide Fragments; Precancerous Conditions; Rats; Rats, Inbred Lew; Receptors, Cholecystokinin; Sincalide; Tetragastrin

The gastrointestinal peptide CCK has been shown to stimulate growth of normal and malignant pancreatic tissue. The CCK receptor possesses several different binding sites for CCK. By using the CCK analog JMV-180, which is a functional agonist at CCK high- and low-affinity receptors and an antagonist at very low affinity receptors, and carbachol, which down-regulates binding to CCK high-affinity receptors, we evaluated which receptor is involved in growth of human pancreatic cancer cells. PANC-1 and MIA PaCa-2 human pancreatic cancer cell lines were grown for four to six days in the presence or absence of JMV-180 (10(-10)-10(-6) M) alone or in combination with carbachol (10 mM). Growth was evaluated by counting cells and by [3H]thymidine incorporation. JMV-180 increased cell number in PANC-1 and MIA PaCa-2 cells 123% and 86%, respectively, over controls (P = 0.004). DNA synthesis by [3H]thymidine uptake was increased 64% and 40% in PANC-1 and MIA PaCa-2 cells, respectively, over controls (P < 0.001). The trophic effect of JMV-180 was not inhibited by the addition of carbachol. Since JMV-180 stimulated the growth and since the effect was not inhibited by carbachol, we suggest that the growth effects of CCK in pancreatic cancer cells are mediated by the low-affinity receptor.

Topics: Carbachol; Cell Count; DNA, Neoplasm; Humans; Pancreatic Neoplasms; Receptors, Cholecystokinin; Sincalide; Tumor Cells, Cultured

Topics: Animals; Blotting, Northern; Gene Expression; Iodine Radioisotopes; Liver; Male; Pancreas; Pancreatic Neoplasms; Rats; Rats, Inbred Lew; Receptors, Cholecystokinin; RNA, Messenger; Sincalide; Tumor Cells, Cultured

The pancreatic zymogen granule membrane protein GP-2 was introduced into cells of exocrine or endocrine origin by transfection of its cDNA in order to investigate the mechanisms by which proteins are specifically incorporated into the membranes of secretory granules. Permanent transformants expressing GP-2 were isolated from exocrine pancreatic-derived AR42J cells as well as AtT20 cells of anterior pituitary origin and insulinoma-derived Rin5F cells. In AR42J cells, GP-2 was localized by immunofluorescence and immunoelectron microscopy to the endogenous zymogen-like granules as well as to the plasma membrane. In experiments supporting the localization data, incubation of the AR42J transformants with the secretagogue cholecystokinin (CCK8) resulted in enhanced release of a shed form of GP-2 into the medium in parallel with amylase, suggesting that the two proteins were secreted from the same compartment. By contrast, when expressed in AtT20 cells, the protein was found by immunofluorescence microscopy on the plasma membrane as well as in intracellular vesicles that differed in size and location from the endogenous secretory vesicles. By electron microscopy, large (approximately 0.5 micron) multivesicular structures were observed. Single- and double-label immunoelectron microscopy demonstrated that these large organelles labeled with anti-GP-2 antibodies, whereas the smaller adrenocorticotropic hormone (ACTH)-containing secretory vesicles did not. In permanent transformants of Rin5F cells, GP-2 was also excluded from the insulin-containing granules and found in multivesicular bodies similar to those in the AtT20 cells and containing the endosomal/lysosomal marker endolyn-78. Despite the apparent accumulation of GP-2 in lysosome-like structures, it turned over slowly and did not undergo rapid endocytosis from the cell surface. We conclude that GP-2 is targeted to secretory granule membranes by cell type-specific mechanisms that likely involve its interaction with other membrane or content proteins expressed only in the exocrine cells.

Topics: Amylases; Animals; Cell Line; Cell Membrane; Cloning, Molecular; Cytoplasmic Granules; GPI-Linked Proteins; Insulinoma; Islets of Langerhans; Kinetics; Membrane Glycoproteins; Microscopy, Immunoelectron; Organelles; Pancreas; Pancreatic Neoplasms; Phosphatidylinositol Diacylglycerol-Lyase; Phosphoric Diester Hydrolases; Pituitary Gland, Anterior; Sincalide; Transfection; Tumor Cells, Cultured

In this investigation we studied pancreastatin (PST) secretion from a human PST producing cell line (QGP-1N) in response to various secretagogues. Immunocytochemical study revealed the immunoreactivity of PST and somatostatin (SMT) in the same cells of a monolayer culture. Ki-ras DNA point mutation on codon 12 was found. Carbachol stimulated secretion of PST and SMT and intracellular Ca2+ mobilization in the range of 10(-6)-10(-4) M. The secretion and Ca2+ mobilization were inhibited by atropine, a muscarinic receptor antagonist. Phorbol ester and calcium ionophore (A23187) stimulated secretion of PST and SMT. The removal of extracellular calcium suppressed both secretions throughout stimulation with 10(-5) M carbachol. Fluoride, a well-known activator of guanine nucleotide binding (G) protein, stimulated intracellular Ca2+ mobilization and secretion of PST and SMT in a dose-dependent manner in the range of 5-40 mM. Also, 10(-5) M carbachol and 20 mM fluoride stimulated inositol 1,4,5-triphosphate production. However, cholecystokinin and gastrin-releasing peptide did not stimulate Ca2+ mobilization or secretion of the two peptides. These results suggest that secretion of PST and SMT from QGP-1N cells is regulated mainly by acetylcholine in a parallel fashion through muscarinic receptors coupled to the activation of polyphosphoinositide breakdown by a G-protein and that increases in intracellular Ca2+ and protein kinase C play an important role in stimulus-secretion coupling.

Topics: Adenoma, Islet Cell; Calcium; Carbachol; Chromogranin A; Genes, ras; Humans; Inositol 1,4,5-Trisphosphate; Pancreatic Hormones; Pancreatic Neoplasms; Sincalide; Somatostatin; Tumor Cells, Cultured

Cholecystokinin is thought to be an important factor regulating the growth of human pancreatic cancers. The study was designed to evaluate the effects of the cholecystokinin antagonist loxiglumide (CR1505) on the growth of human pancreatic cancer.. Human gastrointestinal cancer xenografted tumors (one esophageal, one gastric, two colorectal, two biliary tract, and two pancreatic cancers) were transplanted into nude mice. The mice were given CR1505 at 250 mg/kg daily for 14 days, either subcutaneously or intragastrically, and the tumor volumes before and after treatment were compared. In vitro effects of CR1505 were assessed by measuring the DNA synthesis (3H-thymidine incorporation).. CR1505 inhibited the growth of the two pancreatic cancer lines but did not inhibit the growth of the other lines. CR1505 also inhibited in vitro DNA synthesis in the two pancreatic cancer lines at lower concentrations than in the other lines. This pancreatic cancer-specific inhibitory effect of CR1505 was retarded by exogenously administered cholecystokinin in one pancreatic cancer line but was augmented in the other line. The effect of CR1505 was inhibited by oral administration of the trypsin-inhibitor camostate (FOY-305) in both pancreatic cancer lines.. These results suggest that CR1505 may specifically inhibit the growth of human pancreatic cancers and may be suitable for clinical study. However, its antiproliferative effect may not necessarily be dependent on its cholecystokinin-antagonism but may be mediated through the proteolytic enzymes found in the lysosomes of the pancreatic cancer cells.

Topics: Animals; Cell Division; Chloroquine; Cholecystokinin; DNA; Esters; Gabexate; Guanidines; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Transplantation; Organ Culture Techniques; Pancreatic Neoplasms; Proglumide; Sincalide; Transplantation, Heterologous

Cholecystokinin (CCK-A) and gastrin (CCK-B) receptors have been demonstrated in the azaserine-induced rat pancreatic carcinoma DSL-6. In order to determine at what stage in azaserine-induced pancreatic carcinogenesis gastrin (CCK-B) receptors are first expressed, we examined the binding of [125I]gastrin-I to normal rat pancreas, azaserine-induced premalignant pancreatic nodules, grossly normal internodular pancreas, and DSL-6 carcinoma. We observed that specific gastrin binding was absent in normal pancreas, premalignant nodules, and internodular pancreas, and also reconfirmed our previous report of marked overexpression of gastrin (CCK-B) receptors in the DSL-6 carcinoma. Specific cholecystokinin (CCK) binding was present in all pancreatic tissue types tested. Therefore, we conclude that the presence of gastrin (CCK-B) receptors in the azaserine-induced pancreatic carcinoma DSL-6, in contrast to their absence in premalignant nodules, suggests that the expression of the gastrin (CCK-B) receptor may be important in the transformation from premalignant nodules to pancreatic cancer.

Topics: Animals; Azaserine; Cell Transformation, Neoplastic; Gastrins; Male; Pancreas; Pancreatic Neoplasms; Rats; Rats, Inbred Lew; Receptors, Cholecystokinin; Sincalide

The gastrointestinal peptide cholecystokinin (CCK) has been shown to stimulate growth of human pancreatic adenocarcinoma in vitro and in vivo, although CCK receptors have not been identified in pancreatic cancer cells. The purpose of this study was to characterize the CCK receptors in pancreatic cancer cells and to correlate the receptor binding studies with the trophic action of CCK agonists and antagonists. With the use of homogenates of PANC-1 human pancreatic cancer cell line grown in culture, the binding of 125I-labeled CCK octapeptide (125I-CCK-8) was examined under various conditions to characterize the CCK receptor. Specific and saturable binding of 125I-CCK-8 was detected in PANC-1 cells; data were consistent with a single binding site. Scatchard analysis yielded a binding affinity [dissociation constant (Kd)] of 2.8 nM and a binding capacity of 26 fmol/mg protein. Binding was dependent on protein concentration, time, temperature, the presence of protease inhibitors, and pH and was sensitive to Na+, K+, Mg2+, and ethylene glycolbis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid. Competition experiments indicated that L-365,260, a selective CCK-B (gastrin) receptor antagonist, was the most potent displacer of 125I-CCK-8, and no significant displacement of binding was found with the selective CCK-A receptor antagonist. Growth of PANC-1 cells in culture was stimulated by CCK at a concentration consistent with the Kd, and CCK-stimulated growth was inhibited by the CCK-B receptor antagonist (L-365,260) not the CCK-A receptor antagonist (L-364,718).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Binding, Competitive; Cations; Cholecystokinin; Humans; Hydrogen-Ion Concentration; Osmolar Concentration; Pancreatic Neoplasms; Receptors, Cholecystokinin; Sincalide; Temperature; Time Factors; Tumor Cells, Cultured

Cholecystokinin (CCK) has been shown to stimulate the growth of both normal pancreas and azaserine-induced putative preneoplastic pancreatic lesions in the rat. The present study was performed to determine whether these effects are mediated by way of CCK-A receptors, CCK-B receptors, or both. Sixteen-day-old male Lewis rats were given i.p. injections of azaserine at 30 mg/kg body weight. Starting on day 21, rats were given s.c. injections, 5 days/week for 16 consecutive weeks, of either (a) CCK octapeptide (nonselective CCK agonist) (2.50 micrograms/kg body weight, n = 17), (b) tert-butyloxycarbonyl-Trp-Lys(epsilon-N-2-methylphenylaminocarbonyl++ +)-Asp- (N-methyl)-Phe-NH2 (highly selective CCK-A agonist) (1.84 micrograms/kg body weight, n = 18), (c) [(2R,3S)-beta-MePhe28,N-MeNle31]CCK26-33 (highly selective CCK-B agonist) (2.40 micrograms/kg body weight, n = 18), or (d) normal saline solution (control, n = 17). Rats were subsequently sacrificed, pancreatic weights were determined, and quantitative morphometric analysis of atypical acinar cell foci and nodules was performed. Both CCK octapeptide and the selective CCK-A agonist tert-butyloxycarbonyl-Trp-Lys(epsilon-N-2- methylphenylaminocarbonyl)-Asp-(N-methyl)-Phe-NH2 stimulated pancreatic growth and the development of acidophilic atypical acinar cell foci and nodules. Furthermore, the effect produced by the selective CCK-A agonist tert-butyloxycarbonyl-Trp-Lys(epsilon-N-2- methylphenylaminocarbonyl)-Asp-(N-methyl)-Phe-NH2 was greater than that produced by CCK octapeptide. In contrast, the selective CCK-B agonist [(2R,3S)-beta-MePhe28,N-MeNle31]CCK26-33 had no effect. These findings suggest that the growth of putative preneoplastic lesions (acidophilic atypical acinar cell foci and nodules) in the rat pancreas during the early stages of azaserine-induced pancreatic carcinogenesis is mediated specifically by way of CCK-A receptors.

Topics: Animals; Azaserine; Cholecystokinin; Chronic Disease; Male; Organ Size; Pancreas; Pancreatic Neoplasms; Pancreatitis; Peptide Fragments; Precancerous Conditions; Rats; Rats, Inbred Lew; Receptors, Cholecystokinin; Sincalide; Tetragastrin

Gastrointestinal hormones and neuropeptides are known to regulate growth of various normal gastrointestinal tissues and many cancers. Since cholecystokinin (CCK) is considered the most potent trophic factor for the exocrine pancreas, we studied its effect on growth of an acinar cell tumor, initially induced by azaserine and transplanted to the rat, in comparison with the normal pancreas. When tumors became palpable, rats were treated three times daily for 12 or 14 days with CCK-8 or NaCl 0.9% (controls) alone or in combination with the CCK receptor antagonist CR1409 (10 mg/kg) administered subcutaneously twice daily. Then tumors and pancreata were analyzed for their size, composition, and CCK receptors. Tumor volume, weight, and protein content, RNA, DNA, and enzymes decreased after CCK-8 treatment in a dose-dependent manner, the maximal effect being observed with 4-micrograms/kg treatment. This inhibitory effect was partially suppressed by CR1409, which by itself also reduced tumor growth, but to a lesser degree. CCK-8 exerted a stimulating effect on growth of the normal pancreas with low doses (1 and 2 micrograms/kg) and an inhibitory effect or no effect with a higher dose (4 micrograms/kg). CR1409 prevented this latter effect, but did not affect by itself the normal pancreas. These findings suggest that CCK-8 inhibits growth of an acinar cell tumor grafted to the rat; this effect is mediated by the occupation of specific CCK receptors present in high density on these cells. In contrast, CCK-8 exerts a biphasic effect on the normal pancreas as a function of its dose.

Topics: Animals; Carcinoma; Cell Division; Dose-Response Relationship, Drug; Neoplasm Transplantation; Pancreatic Neoplasms; Proglumide; Rats; Rats, Inbred Lew; Receptors, Cholecystokinin; Sincalide

The rat insulinoma RIN 5F and the mouse pituitary AtT-20 cell line, which are known to express several biologically active peptides, were found to express CCK mRNA, to correctly process, and to release immunoreactive cholecystokinin (CCK) peptides. They expressed low levels of these peptides (about 0.4 and 0.2 ng/mg protein, respectively) and both cell lines processed pro-CCK to a form which co-eluted with CCK 8 sulfate on Sephadex gel filtration chromatography and HPLC. The major CCK 8 immunoreactive peptide which they secreted co-eluted with CCK 8 on Sephadex G-50 chromatography. The secretion of CCK from both cell lines was significantly enhanced by treatment for 24 h with forskolin + IBMX (3-isobutyl-1-methyl-xanthine, a phosphodiesterase inhibitor). This treatment also doubled the CCK content of the AtT-20 cells. It appears that the ability of different endocrine tumor cells to express and process CCK is not as uncommon as previously thought. These cells should be useful for future studies of CCK expression, processing, and regulation of secretion.

Topics: 1-Methyl-3-isobutylxanthine; Animals; Blotting, Northern; Cholecystokinin; Chromatography, High Pressure Liquid; Colforsin; Cyclic AMP; Gene Expression; Insulinoma; Mice; Pancreatic Neoplasms; Pituitary Neoplasms; Protein Precursors; Rats; RNA, Messenger; Sincalide; Tumor Cells, Cultured

Many reports have emphasized the role of gastrin as a growth factor for normal gastrointestinal mucosa and gastrointestinal cancers. Recent studies have pointed out that this peptide acts also as a growth factor for the pancreatic cancer cell line AR42J. This effect is mediated by gastrin [cholecystokinin (CCK)-B] receptors. In the present study, we investigated gastrin (CCK-B) receptor expression in the azaserine-induced rat pancreatic carcinoma DSL-6, comparing it to normal rat pancreas, and we also characterized CCK receptor subtypes in this tumor. The results showed that there is extensive gastrin binding to the DSL-6 pancreatic carcinoma. No evidence of specific gastrin binding to normal pancreas was found. Analysis of the ability of gastrin-17-I to inhibit 125I-gastrin-I binding demonstrated that gastrin bound to a single class of receptors with a Kd of 0.21 +/- 0.04 nM and a binding capacity of 184 +/- 29 fmol/mg protein. 125I-Gastrin-I binding was inhibited by the specific CCK-B receptor antagonist L365,260 approximately 40 times more effectively than by the specific CCK-A receptor antagonist L364,718. Analysis of the ability of cholecystokinin octapeptide (CCK-8) to inhibit 125I-Bolton-Hunter-CCK-8 binding revealed two CCK binding sites, i.e., a high affinity site and a low affinity site. The observed binding affinities of CCK-8 were then introduced into the computer analysis of the dose-inhibition curve of the ability of gastrin-17-I to inhibit binding of 125I-Bolton-Hunter-CCK-8, which was significantly better fit by a three-site model than by a two-site model. The three sites meet the criteria for CCK-B, high affinity CCK-A, and low affinity CCK-A receptors. The binding capacity of CCK-B receptors constitutes 34% of the total high affinity CCK binding sites. This study demonstrated that DSL-6 pancreatic carcinoma expresses three subtypes of CCK receptors. Gastrin (CCK-B) receptors, which were not detected in normal rat pancreas, constitute about one third of the total high affinity CCK receptors. We suggest that novel expression of gastrin (CCK-B) receptors may be generated by gene mutation or amplification during carcinogenesis and may play an important role in promoting tumor growth.

Topics: Animals; Azaserine; Gastrins; Male; Pancreatic Neoplasms; Rats; Rats, Inbred Lew; Receptors, Cholecystokinin; Sincalide

Cholecystokinin (CCK) exerts an influential effect on the growth of normal pancreas. It is postulated that carcinoma arising from the pancreas may retain some normal pancreatic properties as far as hormone dependency is concerned. In an effort to examine the effect of CCK on the growth of pancreatic cancer, we evaluated the effect of CCK receptor antagonist on the growth of a transplantable adenocarcinoma of the pancreas. For this study we utilized three groups of hamsters with adenocarcinoma of the pancreas transplanted subcutaneously on the right flank. Group I (n = 15) served as control. Group II (n = 15) received CCK receptor antagonist (L-364,718), 0.1 mg/100 g body wt subcutaneously BID. Group III received CCK receptor antagonist in the same dose but treatment was started after tumors became palpable. All animals were examined daily. Latency for tumor growth, tumor size, and body weight were recorded. Animals were sacrificed after 3 weeks and final tumor volume and weight were measured. CCK receptor antagonist (L-364,718) significantly reduced pancreatic carcinoma growth when given immediately after transplantation and also in animals with established tumor. However, this inhibitory effect of L-364,718 was only partial and effective only for a brief time. This finding suggests CCK may have only a minimal influence on the biologic behavior of exocrine pancreatic cancer.

Topics: Adenocarcinoma; Animals; Benzodiazepinones; Cricetinae; Devazepide; Male; Mesocricetus; Neoplasm Transplantation; Pancreas; Pancreatic Neoplasms; Receptors, Cholecystokinin; Sincalide; Succinimides

Cholecystokinin (CCK) is a growth factor for normal pancreas. Numerous studies also suggest that CCK promotes pancreatic carcinogenesis in the rat. Our previous studies suggested that growth of preneoplastic pancreatic foci was stimulated by CCK more than that of normal pancreas. We hypothesized that such differential growth might be due to increased numbers of CCK receptors in neoplastic tissue. Azaserine-induced pancreatic carcinoma (DSL6) had an increased high-affinity CCK receptor binding capacity of 122 +/- 23 (SD) fmol/mg protein compared to 12 +/- 2 fmol/mg protein in normal pancreas (P less than 0.001). The Kd of the high-affinity site was 0.33 +/- 0.04 nM for carcinoma and 0.46 +/- 0.08 nM for normal pancreas (P less than 0.01). The amount of cholecystokinin octapeptide (CCK-8) bound to high-affinity receptor was 8.6 +/- 1.9 fmol/mg protein for DSL6 compared to 0.6 +/- 0.2 fmol/mg protein in normal pancreas (P less than 0.001). Azaserine-induced premalignant nodules were compared to remaining internodular pancreas. Nodules demonstrated a mean high-affinity CCK receptor binding capacity of 38 +/- 9 fmol/mg protein compared to 6 +/- 3 fmol/mg protein in internodular pancreas (P less than 0.001). The amount of CCK-8 bound to high-affinity receptor was 3.1 +/- 0.8 fmol/mg protein in nodules compared to 0.6 +/- 0.3 fmol/mg protein in internodular pancreas (P less than 0.001). Overexpression of high-affinity CCK-8 receptor in premalignant and malignant azaserine-induced tumors may result in a growth advantage relative to normal pancreas.

Topics: Animals; Azaserine; Binding, Competitive; DNA, Neoplasm; Hydrogen-Ion Concentration; Male; Pancreatic Neoplasms; Precancerous Conditions; Rats; Receptors, Cholecystokinin; Sincalide; Succinimides; Temperature; Time Factors

Studies were made of pancreastatin (PST) secretion from a human PST-producing cell line (QGP-1N) in response to various secretagogues. Cells with immunoreactivity for PST were observed in monolayer cultures of QGP-1N cells. Carbachol stimulated PST secretion and the intracellular Ca2+ mobilization concentration dependently in the range of 10(-6)-10(-4) M. The PST secretion and Ca2+ mobilization induced by carbachol were inhibited by atropine. The calcium ionophore (A23187) stimulated PST secretion. However, cholecystokinin and gastrin-releasing peptide did not stimulate either PST secretion or Ca2+ mobilization. Secretin also did not stimulate PST secretion. The glucose concentration in the culture medium had no effect on PST secretion. These results suggest that PST secretion is mainly regulated by acetylcholine through a muscarinic receptor, and that an increase in intracellular Ca2+ plays an important role in stimulus-secretion coupling in QGP-1N cells.

Topics: Acetylcholine; Adenoma, Islet Cell; Atropine; Calcimycin; Calcium; Carbachol; Chromogranin A; Gastrin-Releasing Peptide; Humans; Pancreatic Hormones; Pancreatic Neoplasms; Parasympatholytics; Peptides; Piperidines; Pirenzepine; Receptors, Muscarinic; Sincalide; Tumor Cells, Cultured

We recently reported that human pancreatic cancers differentially respond to the growth inhibitory effects of an estradiol (E2) receptor antagonist, tamoxifen, and a long-acting analogue of somatostatin, Sandostatin. In the present study two human pancreatic cancers, established as xenografts in nude mice, were examined as representative of cancers that respond to either tamoxifen (PGER) or Sandostatin (SKI), for the presence of binding sites for various hormones. Male nude mice were inoculated with either SKI or PGER, by passage of tumor chunks (3 mm2) to the interscapular region. Tumors, obtained from mice after approximately 30 days of in vivo growth, were analyzed for binding to cholecystokinin-octapeptide (CCK), somatostatin and E2, by published procedures, using either crude tumor membranes (CCK), cytosol and nuclear fractions (E2), or cryostat sections of whole tumors (somatostatin). SKI was highly positive for high-affinity (Kd = approximately 1 nM) CCK binding sites at the time of resection with a binding capacity of approximately 1000 fmol/mg protein. With increasing passages, the total number of high-affinity binding sites for CCK, were reduced to non-detectable levels in SKI tumors, while non-saturable binding (Kd = greater than 10 nM) became increasingly evident. Early passages of PGER tumors were similarly positive for high-affinity binding sites for CCK, that steeply declined with increasing passages. Specific binding sites for E2, were observed only in the cytosolic fractions of PGER, with a high binding affinity (Kd = approximately 0.05 nM) and a low binding capacity (15 +/- 3 fmol/mg cytosolic proteins), at all passages examined; E2 binding sites were not detected in cytosolic and nuclear fractions of SKI and in the nuclei of PGER, at all passages. SKI and PGER at different passages were examined for somatostatin binding, and both the early and late passages of PGER were devoid of somatostatin binding sites, while SKI tumors were positive for them. Based on the above results, it appears likely that Sandostatin directly inhibited the growth of SKI tumors, since SKI was positive for somatostatin binding sites; it appears less likely that Sandostatin indirectly mediated its inhibition by attenuating possible stimulatory effects of CCK. Growth inhibitory effects of tamoxifen on PGER were apparently via E2 binding sites, since only the tumors positive for E2 binding sites (PGER) responded to tamoxifen; it remains to be determined if tamoxifen

Topics: Adenocarcinoma; Animals; Autoradiography; Carcinoma, Intraductal, Noninfiltrating; Estradiol; Humans; Iodine Radioisotopes; Kinetics; Mice; Mice, Nude; Neoplasm Transplantation; Pancreatic Neoplasms; Receptors, Cholecystokinin; Receptors, Estradiol; Receptors, Neurotransmitter; Receptors, Somatostatin; Sincalide; Somatostatin; Transplantation, Heterologous; Tumor Cells, Cultured

A new cell line was established from a liver metastasis of a human pancreatic adenocarcinoma. The cell line, MDAPanc-3, which arose from a moderately differentiated adenocarcinoma, produces carbonic anhydrase II mRNA, but no detectable levels of insulin or alpha amylase mRNA. The stem line chromosome number was determined to be 43, with six marker chromosomes. Growth of MDAPanc-3 is stimulated by cholecystokinin (CCK) fragment 26-33. The cell line will be useful in further studies on the mechanism(s) by which CCK stimulates growth of certain human pancreatic adenocarcinomas and normal human pancreatic exocrine tissue.

Topics: Adenocarcinoma; alpha-Amylases; Blotting, Northern; Cell Division; Humans; Insulin; Karyotyping; Keratins; Male; Middle Aged; Molecular Weight; Pancreatic Neoplasms; Protein Biosynthesis; RNA, Neoplasm; Sincalide; Tumor Cells, Cultured

Regulation of intracellular pH (pHi) was studied by dual wavelength fluorometry in monolayers of pancreatic AR42J cells loaded with the fluorescent probe 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. In cells superfused with N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-buffered solution at pH 7.40, basal pHi was determined to be 7.15 +/- 0.13. Na(+)-H+ exchange could be demonstrated in both resting cells and cells subjected to acid loading by use of transient exposure to NH4Cl. Na(+)-H+ exchange was completely blocked by 300 microM amiloride and was dependent on extracellular Na+ (apparent Km = 25 mM). When the concentration of the NH4Cl pulse was varied (0.5-25 mM), the rate of pHi recovery increased as pHi became acidic, reaching a maximum of 0.007 pH units/s at pHi of 6.4. Gastrointestinal hormones, including pentagastrin, cholecystokinin, and bombesin, increased the rate of Na(+)-H+ exchange without affecting cellular buffer capacity (21.5 +/- 1.8 mM/pH unit), thereby leading to an intracellular alkalinization. This was accompanied by a shift in the curve of Na(+)-H+ exchange as a function of pHi to more alkaline values, although the maximum rate of pH recovery was unchanged. Neither protein kinase C nor Ca2+ could be conclusively linked to activation of Na(+)-H+ exchange, raising the possibility of a more direct, receptor-controlled mechanism.

Topics: Amiloride; Amino Acid Sequence; Animals; Bombesin; Carbachol; Carrier Proteins; Cell Line; Gastrointestinal Hormones; Hydrogen-Ion Concentration; Kinetics; Molecular Sequence Data; Pancreatic Neoplasms; Pentagastrin; Rats; Sincalide; Sodium Chloride; Sodium-Hydrogen Exchangers; Substance P; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured

Cholecystokinin (CCK) receptors were investigated in the tumoral acinar cell line AR 4-2 J derived from rat pancreas, after preincubation with 20 nM dexamethasone. At steady state binding at 37 degrees C (i.e., after a 5 min incubation), less than 10% of the radioactivity of [125I]BH-CCK-9 (3-(4-hydroxy-[125I]iodophenyl)propionyl (Thr34, Nle37) CCK(31-39)) could be washed away from intact cells with an ice-cold acidic medium, suggesting high and rapid internalization-sequestration of tracer. By contrast, more than 85% of the tracer dissociated rapidly after a similar acid wash from cell membranes prelabelled at steady state. In intact AR 4-2 J cells, internalization required neither energy nor the cytoskeleton framework. Tracer internalization was reversed partly but rapidly at 37 degrees C but slowly at 4 degrees C. In addition, two degradation pathways of the tracer were demonstrated, one intracellular and one extracellular. Intracellular degradation occurred at 37 degrees C but not at 20 degrees C and resulted in progressive intracellular accumulation of [125I]BH-Arg that corresponded, after 1 h at 37 degrees C, to 35% of the radioactivity specifically bound. This phenomenon was not inhibited by serine proteinase inhibitors and modestly only by monensin and chloroquine. Besides, tracer degradation at the external cell surface was still observable at 20 degrees C and yielded a peptide (probably [125I]BH-Arg-Asp-Tyr(SO3H)-Thr-Gly). This degradation pathway was partly inhibited by bacitracin and phosphoramidon while thiorphan, an inhibitor of endopeptidase EC 3.4.24.11, was without effect.

Topics: Animals; Arsenicals; Binding, Competitive; Cell Membrane; Chloroquine; Cholecystokinin; Cytochalasin D; Dinitrophenols; Endocytosis; Gastrins; Hydrogen-Ion Concentration; Iodine Radioisotopes; Kinetics; Pancreas; Pancreatic Neoplasms; Rats; Sincalide; Succinimides; Temperature; Tumor Cells, Cultured

Proliferation of endocrine cells was found to occur during early, i.e., first 12 weeks, exocrine pancreatic carcinogenesis after 6 weekly treatments of Syrian hamsters with the pancreatic carcinogen N-nitrosobis(2-oxopropyl)amine (BOP). Cells containing insulin (Ins), glucagon (Glu), and somatostatin (Som) were noted in all stages of tumor development and were present in adenocarcinomas and in metastases to the liver. Some of the cancer cells were of amphicrine (hybrid) type, i.e., produced both mucin and endocrine substances. Measurement of these hormones revealed a significant decrease in plasma Ins during early stages of carcinogenesis with concomitant increase of Ins level in pancreatic juice at 12 weeks after 6 weekly BOP treatments. Plasma Glu and Som were not changed. The changes noted, particularly in relation to Ins, suggest that proliferation of endocrine cells in pancreatic carcinogenesis may be associated with alterations in hormone secretion.

Topics: Animals; Carcinogens; Cricetinae; Glucagon; Insulin; Insulin Secretion; Islets of Langerhans; Male; Mesocricetus; Nitrosamines; Pancreas; Pancreatic Juice; Pancreatic Neoplasms; Reference Values; Secretin; Sincalide; Somatostatin

In view of the trophic action of gastrointestinal hormones on the exocrine pancreas, the effects of secretin, octapeptide of cholecystokinin (CCK-8), and desglugastrin on the growth of hamster pancreatic well differentiated adenocarcinoma were investigated in vitro. Desglugastrin exhibited the greatest effect on thymidine incorporation into these cells after a lag period of 96 h. Doses of desglugastrin in the range from 30 to 270 ng/mL caused a significant and dose-dependent increase in thymidine incorporation. Higher doses of this peptide led to a decreased response. Secretin also increased thymidine incorporation, but the response was less than that induced by gastrin. Prolonged incubation with secretin for 96 h increased tritiated thymidine incorporation in a log-dose fashion in the range of 30 to 270 ng/mL. Doses of CCK-8 in the range of 90 to 810 ng/mL significantly increased thymidine incorporation after 48 h of incubation. Following 72 h of incubation, only the dose of 270 ng/mL continued to exhibit a significant stimulation. Our study suggests that the gastrointestinal hormones could directly increase the growth of pancreatic carcinoma cells, act synergistically with endogenous growth factors, or stimulate the local production of these factors. In any event, our results that gastrin, secretin, and CCK can stimulate the growth of pancreatic ductal tumor cells in tissue cultures, support earlier findings on normal and malignant pancreatic parenchyma.

Topics: Adenocarcinoma; Amino Acid Sequence; Animals; Cell Cycle; Cell Line; Cricetinae; DNA Replication; DNA, Neoplasm; Gastrins; Kinetics; Molecular Sequence Data; Pancreatic Neoplasms; Secretin; Sincalide; Thymidine; Tritium

Feeding of raw soya flour or other trypsin inhibitors such as camostate is a well-established method for promoting growth of (pre)neoplastic foci induced in the exocrine pancreas of rats by azaserine. The effect of trypsin inhibitors is thought to be mediated through an increased release of cholecystokinin. Using the specific cholecystokinin receptor antagonist lorglumide (CR-1409), we performed a 16-wk study to investigate the potential of this drug in inhibiting growth of putative preneoplastic foci and to determine whether and to what extent cholecystokinin is responsible for the effect of trypsin inhibitors on pancreatic growth. After initiation with 30 mg/kg of azaserine at 19 days of age, six groups of 15 rats each received one of the following treatments: camostate, cholecystokinin-8, or gelatin control, either or not in combination with CR-1409, once daily, 3 days wk for 16 wk. Plasma cholecystokinin levels, measured 30 min after the stimulus, were similar after camostate and cholecystokinin octapeptide administration. After 16 wk the pancreata were removed, weighted, and quantitatively analyzed for the number and size of putative preneoplastic foci by light microscopy. Both camostate and cholecystokinin octapeptide stimulated pancreatic growth and development of acidophilic putative preneoplastic foci, whereas growth of basophilic putative preneoplastic foci was inhibited by camostate but stimulated by cholecystokinin. CR-1409 almost completely abolished the effect of cholecystokinin and was found to cause a significant decrease in the effects of camostate. It is concluded that (a) cholecystokinin plays a significant role in camostate-stimulated growth of acidophilic putative preneoplastic foci in rat pancreas and (b) CR-1409 inhibits growth of putative preneoplastic foci induced in rat pancreas by azaserine and hence may be of potential value for the treatment of pancreatic cancer in humans.

Topics: Animals; Azaserine; Cholecystokinin; Esters; Gabexate; Glutamine; Guanidines; Male; Pancreatic Neoplasms; Precancerous Conditions; Proglumide; Rats; Rats, Inbred Strains; Receptors, Cholecystokinin; Sincalide; Trypsin Inhibitors

The secretion of protein, like cell proliferation, is an integrated response that reflects structural organization of the cell periphery. Stimulation of protein secretion was thus utilized for comparison of integrated responses of the cell periphery in pancreatic acinar carcinoma of the rat and integrated responses in normal rat pancreas. Results of this comparison include: a) The stimulation of protein secretion in acinar carcinoma fragments by carbamylcholine chloride and cholecystokinin octapeptide, pancreatic secretagogues that interact with specific plasma membrane receptors, was only a fraction (one-fifth to one-half) of that observed in normal pancreatic minilobules. b) The Ca2+ ionophore A23187 and the cyclic nucleotide N6,O2'-dibutyryl cyclic AMP, secretagogues that act independently of specific membrane receptors, did not stimulate secretion in the acinar carcinoma. The observed quantitative and qualitative differences in protein secretion indicate fundamental differences in cell periphery organization between the normal and transformed acinar cells of pancreas.

Topics: Animals; Bucladesine; Calcimycin; Carbachol; Carcinoma; Cell Membrane; Cholecystokinin; Dose-Response Relationship, Drug; In Vitro Techniques; Pancreas; Pancreatic Neoplasms; Peptide Fragments; Proteins; Rats; Secretory Rate; Sincalide; Temperature