Effect of aqueous extract of seed of broccoli on inflammatory cytokines and Helicobacter pylori infection: a randomized, double-blind, controlled trial in patients without atrophic gastritis.

The purpose of this study was to investigate the anti-inflammatory effect of an aqueous extract of seed of broccoli (AESB) in Helicobacter pylori (HP)-infected patients without atrophic gastritis. This was a double-centre, randomized, double-blind, controlled study. A total of 110 HP-infected subjects were randomized to receive either AESB or placebo for 2 months. Inflammatory cytokine (IL-8, IFN-γ, TNF-α, CRP, IL-17A, IL-1ß, IL-18), pepsinogen I, II (PG I, PG II), and gastrin-17 (G-17) measurements and 13C-urea breath tests were performed at baseline and at 60 days. At 60 days, there was no significant difference in any of the inflammatory cytokines, pepsinogen or gastrin between the two groups. However, IL-8, IFN-γ, PG I, PG I/PG II ratio (PGR), and G-17 were reduced by 9.02 pg/mL, 5.08 pg/mL, 24.56 ng/mL, 1.75 and 0.3 pmol/L, respectively, in the AESB group compared with baseline (all P < 0.05). The HP eradication rates in the AESB group and placebo group were 11.11 and 3.70% at 60 days, respectively (P > 0.05). No treatment-related adverse events were reported. Thus, AESB may reduce the risk of gastric mucosal lesions and decrease the risk of gastric cancer by relieving inflammatory cytokines. The safety profile of AESB was satisfactory. This study is registered with the Chinese Clinical Trials Registry (Registration No. ChiCTR2100054249).

A GLP-1/glucagon (GCG)/CCK2 receptors tri-agonist provides new therapy for obesity and diabetes.

BACKGROUND AND PURPOSE: Glucagon-like peptide-1 (GLP-1) and glucagon (GCG) receptor dual agonist have promising therapeutic effects in the treatment of obesity and diabetes. Moreover, GLP-1 and cholecystokinin 2 (CCK2 ) dual agonists have been shown to restore pancreas function and improve glycaemic control in preclinical studies. We describe, for the first time, the beneficial effects of GLP-1/glucagon receptor and GLP-1/CCK2 dual agonists, which can be integrated into one peptide, resulting in significant anti-diabetes and anti-obesity effectiveness. EXPERIMENTAL APPROACH: The in vitro potency of this novel peptide Xenopus (x) GLP-1/GCG/CCK2 tri-agonist (xGLP/GCG/gastrin) against GLP-1, GCG, CCK1 and CCK2 receptors was determined on cells expressing the corresponding receptors by cAMP accumulation or ERK1/2 phosphorylation assays. The in vivo anti-diabetes and anti-obesity effects of this tri-agonist xGLP/GCG/gastrin were studied in both db/db and diet induced obesity (DIO) mice. KEY RESULTS: xGLP/GCG/gastrin was a potent and selective GLP-1, GCG and CCK2 tri-agonist. In DIO mice, the metabolic benefits of xGLP-1/GCG/gastrin, such as reduction of body weight and hepatic lipid contents were significantly better than those of the peptide ZP3022 (GLP-1/CCK-2 dual agonist) and liraglutide. In a short-term study in db/db mice, xGLP/GCG/gastrin treatment had considerable effects, increasing islet numbers, islet areas and insulin content. In a long-term treatment study using db/db mice, xGLP-1/GCG/gastrin showed a significantly and sustained improvement in glucose tolerance and glucose control compared with that of liraglutide, ZP3022, cotadutide (GLP-1/GCG dual agonist) and xGLP/GCG-15. CONCLUSIONS AND IMPLICATIONS: These results demonstrate the therapeutic potential of xGLP-1/GCG/gastrin for the treatment of obesity and diabetes.

Pharmacological inhibition of mTORC1 increases CCKBR-specific tumor uptake of radiolabeled minigastrin analogue [177Lu]Lu-PP-F11N.

Rationale: A high tumor-to-healthy-tissue uptake ratio of radiolabeled ligands is an essential prerequisite for safe and effective peptide receptor radionuclide therapy (PRRT). In the present study, we searched for novel opportunities to increase tumor-specific uptake of the radiolabeled minigastrin analogue [177Lu]Lu-DOTA-(DGlu)6-Ala-Tyr-Gly-Trp-Nle-Asp-Phe-NH2 ([177Lu]Lu-PP-F11N), that targets the cholecystokinin B receptor (CCKBR) in human cancers. Methods: A kinase inhibitor library screen followed by proliferation and internalization assays were employed to identify compounds which can increase uptake of [177Lu]Lu-PP-F11N in CCKBR-transfected human epidermoid carcinoma A431 cells and natural CCKBR-expressing rat pancreatic acinar AR42J cells. Western blot (WB) analysis verified the inhibition of the signaling pathways and the CCKBR level, whereas the cell-based assay analyzed arrestin recruitment. Biodistribution and SPECT imaging of the A431/CCKBR xenograft mouse model as well as histological analysis of the dissected tumors were used for in vivo validation. Results: Our screen identified the inhibitors of mammalian target of rapamycin complex 1 (mTORC1), which increased cell uptake of [177Lu]Lu-PP-F11N. Pharmacological mTORC1 inhibition by RAD001 and metformin increased internalization of [177Lu]Lu-PP-F11N in A431/CCKBR and in AR42J cells. Analysis of protein lysates from RAD001-treated cells revealed increased levels of CCKBR (2.2-fold) and inhibition of S6 phosphorylation. PP-F11N induced recruitment of ß-arrestin1/2 and ERK1/2 phosphorylation. In A431/CCKBR-tumor bearing nude mice, 3 or 5 days of RAD001 pretreatment significantly enhanced tumor-specific uptake of [177Lu]Lu-PP-F11N (ratio [RAD001/Control] of 1.56 or 1.79, respectively), whereas metformin treatment did not show a significant difference. Quantification of SPECT/CT images confirmed higher uptake of [177Lu]Lu-PP-F11N in RAD001-treated tumors with ratios [RAD001/Control] of average and maximum concentration reaching 3.11 and 3.17, respectively. HE staining and IHC of RAD001-treated tumors showed a significant increase in necrosis (1.4% control vs.10.6% of necrotic area) and the reduction of proliferative (80% control vs. 61% of Ki67 positive cells) and mitotically active cells (1.08% control vs. 0.75% of mitotic figures). No significant difference in the tumor vascularization was observed after five-day RAD001 or metformin treatment. Conclusions: Our data demonstrates, that increased CCKBR protein level by RAD001 pretreatment has the potential to improve tumor uptake of [177Lu]Lu-PP-F11N and provides proof-of-concept for the development of molecular strategies aimed at enhancing the level of the targeted receptor, to increase the efficacy of PRRT and nuclear imaging.

The Influence of Different Spacers on Biological Profile of Peptide Radiopharmaceuticals for Diagnosis and Therapy of Human Cancers.

BACKGROUND: Cancer is the leading cause of death worldwide. Early detection can reduce the disadvantageous effects of diseases and the mortality in cancer. Nuclear medicine is a powerful tool that has the ability to diagnose malignancy without harming normal tissues. In recent years, radiolabeled peptides have been investigated as potent agents for cancer detection. Therefore, it is necessary to modify radiopeptides in order to achieve more effective agents. OBJECTIVE: This review describes modifications in the structure of radioconjugates with spacers who have improved the specificity and sensitivity of the peptides that are used in oncologic diagnosis and therapy. METHODS: To improve the biological activity, researchers have conjugated these peptide analogs to different spacers and bifunctional chelators. Many spacers of different kinds, such as hydrocarbon chain, amino acid sequence, and poly (ethyleneglycol) were introduced in order to modify the pharmacokinetic properties of these biomolecules. RESULTS: Different spacers have been applied to develop radiolabeled peptides as potential tracers in nuclear medicine. Spacers with different charge and hydrophilicity affect the characteristics of peptide conjugate. For example, the complex with uncharged and hydrophobic spacers leads to increased liver uptake, while the composition with positively charged spacers results in high kidney retention. Therefore, the pharmacokinetics of radio complexes correlates to the structure and total charge of the conjugates. CONCLUSION: Radio imaging technology has been successfully applied to detect a tumor in the earliest stage. For this purpose, the assessment of useful agents to diagnose the lesion is necessary. Developing peptide radiopharmaceuticals using spacers can improve in vitro and in vivo behavior of radiotracers leading to better noninvasive detection and monitoring of tumor growth.

Vaccine against gastrin, a polyclonal antibody stimulator, decreases pancreatic cancer metastases.

Growth of pancreatic cancer is stimulated by gastrin in both a paracrine and an autocrine fashion. Traditional therapies have not significantly improved survival, and recently pancreatic cancer has been deemed a "cold" tumor due to its poor response to immunotherapy. Strategies to improve survival of pancreatic cancer are desperately needed. In the current investigation, we studied the effects of an anti-gastrin cancer vaccine, polyclonal antibody stimulator (PAS; formerly called G17DT and Gastrimmune), used alone or in combination with a programmed cell death receptor (PD)-1 immune checkpoint antibody on pancreatic cancer growth, metastases, and the tumor microenvironment (TME). Immune-competent female C57BL/6 mice bearing syngeneic orthotopic murine pancreatic cancer treated with PAS had significantly smaller tumors and fewer metastases. Examination of the TME demonstrated decreased fibrosis with fewer M2 and more M1 tumor-associated macrophages. Expression of the E-cadherin gene was significantly increased and expression of the TGFßR2 gene was decreased compared with controls. Mice treated with PAS or the combination of PAS and PD-1 antibody exhibited significantly less tumor expression of phospho-paxillin, the focal adhesion protein ß-catenin, and matrix metalloproteinase-7. This study suggests that inhibition of the cancer-promoting effects of gastrin in pancreatic cancer can decrease metastases by altering the TME and decreasing pathways that activate the epithelial mesenchymal transition. The PAS vaccine appears to change the TME, making it more susceptible to therapy with an immune checkpoint antibody. This novel combination of two immunotherapies may improve survival of pancreatic cancer by decreasing both tumor growth and metastasis formation.NEW & NOTEWORTHY Survival from advanced pancreatic cancer is poor, in part due to dense fibrosis of the tumor microenvironment, increased number of M2-polarized macrophages that promote angiogenesis and invasion, and lack of "target-specific" therapy. Herein, we report that a tumor vaccine that selectively targets gastrin decreases pancreatic cancer growth and metastases. Furthermore, the gastrin vaccine polyclonal antibody stimulator alters the tumor microenvironment rendering it more responsive to immunotherapy with a programmed cell death receptor-1 immune checkpoint antibody.

177Lu-DOTA-coupled minigastrin peptides: promising theranostic agents in neuroendocrine cancers.

Treatment with radionuclide labeled regulatory peptides is a promising tool in the management of patients with inoperable receptor positive neuroendocrine tumors. Peptide receptor lutetium-177 radionuclide therapy currently has gained ample attention due to high specific accumulation of regulatory peptides at tumor cell surface and promising characteristics of ß- and γ-energy photons of lutetium-177 radionuclide. In this study gastrin peptides analogues were labeled with lutetium-177 by subsequent mixing of 177LuCl3 (~ 185 MBq), ammonium acetate buffer of 5 pH, gentistic acid, aqueous solution of gastrin peptide analogues (1 mg/mL) and heating the reaction mixture at 98 °C which resulted in high radiochemical yield (> 96%). Chromatographic analysis was carried out to analyze the radiochemical purity. The shelf life and serum stability results showed the labeled peptides are sufficiently stable up to 4-h. Glomerular filtration rate study results showed moderate filtration through kidneys. The GFR values of 177Lu-MGCL2 and 177Lu-MGCL4 was noted 48 mL/min and 45 mL/min, respectively. Biodistribution and scintigraphy study using rat and rabbit models showed minimal non-target accumulation, moderate uptake by liver and kidneys. The promising radiochemical yield, stability, GFR values and biodistribution results of 177Lu-MGCL2 & 4 indicate, the agents can be tested clinically for PRRT procedures.

177Lu Labeled Cyclic Minigastrin Analogues with Therapeutic Activity in CCK2R Expressing Tumors: Preclinical Evaluation of a Kit Formulation.

Minigastrin (MG) analogues specifically target cholecystokinin-2 receptors (CCK2R) expressed in different tumors and enable targeted radiotherapy of advanced and disseminated disease when radiolabeled with a beta emitter such as 177Lu. Especially truncated MG analogues missing the penta-Glu sequence are associated with low kidney retention and seem therefore most promising for therapeutic use. Based on [d-Glu1,desGlu2-6]MG (MG11) we have designed the two cyclic MG analogues cyclo1,9[γ-d-Glu1,desGlu2-6,d-Lys9]MG (cyclo-MG1) and cyclo1,9[γ-d-Glu1,desGlu2-6,d-Lys9,Nle11]MG (cyclo-MG2). In the present work we have developed and preclinically evaluated a pharmaceutical kit formulation for the labeling with 177Lu of the two DOTA-conjugated cyclic MG analogues. The stability of the kits during storage as well as the stability of the radiolabeled peptides was investigated. A cell line stably transfected with human CCK2R and a control cell line without receptor expression were used for in vitro and in vivo studies with the radioligands prepared from kit formulations. In terms of stability 177Lu-DOTA-cyclo-MG2 showed advantages over 177Lu-DOTA-cyclo-MG1. Still, for both radioligands a high receptor-mediated cell uptake and favorable pharmacokinetic profile combining receptor-specific tumor uptake with low unspecific tissue uptake and low kidney retention were confirmed. Investigating the therapy efficacy and treatment toxicity in xenografted BALB/c nude mice a receptor-specific and comparable therapeutic effect could be demonstrated for both radioligands. A 1.7- to 2.6-fold increase in tumor volume doubling time was observed for receptor-positive tumors in treated versus untreated animals, which was 39-73% higher when compared to receptor-negative tumors. The treatment was connected with transient bone marrow toxicity and minor signs of kidney toxicity. All together the obtained results support further studies for the clinical translation of this new therapeutic approach.

From preclinical development to clinical application: Kit formulation for radiolabelling the minigastrin analogue CP04 with In-111 for a first-in-human clinical trial.

INTRODUCTION: A variety of radiolabelled minigastrin analogues targeting the cholecystokinin 2 (CCK2) receptor were developed and compared in a concerted preclinical testing to select the most promising radiotracer for diagnosis and treatment of medullary thyroid carcinoma (MTC). DOTA-DGlu-DGlu-DGlu-DGlu-DGlu-DGlu-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2 (CP04) after labelling with (111)In displayed excellent characteristics, such as high stability, receptor affinity, specific and persistent tumour uptake and low kidney retention in animal models. Therefore, it was selected for further clinical evaluation within the ERA-NET project GRAN-T-MTC. Here we report on the development of a pharmaceutical freeze-dried formulation of the precursor CP04 for a first multi-centre clinical trial with (111)In-CP04 in MTC patients. MATERIALS AND METHODS: The kit formulation was optimised by adjustment of buffer, additives and radiolabelling conditions. Three clinical grade batches of a final kit formulation with two different amounts of peptide (10 or 50 µg) were prepared and radiolabelled with (111)In. Quality control and stability assays of both the kits and the resulting radiolabelled compound were performed by HPLC analysis. RESULTS: Use of ascorbic acid buffer (pH4.5) allowed freeze-drying of the kit formulation with satisfactory pellet-formation. Addition of methionine and gentisic acid as well as careful selection of radiolabelling temperature was required to avoid extensive oxidation of the Met(11)-residue. Trace metal contamination, in particular Zn, was found to be a major challenge during the pharmaceutical filling process in particular for the 10 µg formulation. The final formulations contained 10 or 50 µg CP04, 25mg ascorbic acid, 0.5mg gentisic acid and 5mg L-methionine. The radiolabelling performed by incubation of 200-250 MBq (111)InCl3 at 90 °C for 15 min resulted in reproducible radiochemical purity (RCP) >94%. Kit-stability was proven for >6 months at +5 °C and at +25 °C. The radiolabelled product was stable for >4h at +25 °C. CONCLUSION: A kit formulation to prepare (111)In-CP04 for clinical application was developed, showing high stability of the kit as well as high RCP of the final product.

A multicenter phase II study of G17DT immunogen plus irinotecan in pretreated metastatic colorectal cancer progressing on irinotecan.

BACKGROUND: The G17DT is a novel human immunogen that raises antibodies to the growth factor gastrin 17 (G17). The purpose of this study was to determine the safety and efficacy of G17DT in combination with irinotecan in patients refractory to irinotecan, and to correlate efficacy with anti-G17 immune response. METHODS: Patients received G17DT immunogen as a single intramuscular injection of 500 µg at weeks 1, 5, 9, and 26. Irinotecan was administered as an intravenous infusion of 125 mg/m(2) over 90 min starting at week 5. Each cycle of treatment consisted of irinotecan administered once weekly for 4 weeks, followed by a 2-week rest period. RESULTS: Of 161 patients who received G17DT, the best overall tumor response in the intent-to-treat population was complete response 0 (0 %), partial response 3 (3 %), stable disease 32 (32 %), and progressive disease 64 (65 %). Median survival was 217 days. About 94 (62 %) subjects evaluable for antibody titers were anti-G17 responders. Survival was significantly longer for anti-G17 responders compared with non-responders (9.0 vs. 5.6 months; P < 0.001). Toxicity was consistent with irinotecan (diarrhea, nausea, anemia, vomiting, fatigue, constipation, anorexia, and neutropenia) except for injection site reactions (pain 42 %, induration 13 %, edema 11 %, erythema 10 %, and three abscesses) attributed to G17DT in 52 % of the patients. CONCLUSION: Treatment with G17DT in combination with irinotecan results in an acceptable anti-G17 immune response, which correlated with promising survival activity in patients refractory to irinotecan-based chemotherapy.

Gastrin: from pathophysiology to cancer prevention and treatment.

Gastrin has been identified as the principal effector of gastric secretion, but several studies have demonstrated its role as a biomarker of cancer risk and as a growth factor for colorectal, stomach, liver, and pancreatic cancer. Hypergastrinemia characterizes autoimmune gastritis, with body and fundic gland atrophy and increased risk for both gastric adenocarcinoma and neuroendocrine tumors. Gastric type I carcinoids develop in the context of autoimmune gastritis because of the stimulus exerted by gastrin on enterochromaffin-like cells and remain gastrin-sensitive for long durations because the removal of hypergastrinemia leads to tumor regression. The treatment of gastric carcinoid is still open to debate, but when the disease frequently relapses, or is multicentric or infiltrating, surgery is advocated or, in the alternative, a costly and long-lasting treatment with long-acting somatostatin analogues is prescribed. A technology allowing the preparation of an immunogen eliciting an immune system response with generation of antibodies against G17 has been developed. This vaccine has been tested in patients with colorectal, pancreatic or advanced gastric cancer. The vaccine has also been used in the treatment of gastric type I carcinoids, and the administration of G17DT in patients harboring these lesions leads to carcinoid regression. Antigastrin vaccination in the treatment of gastrointestinal cancer obviously needs validation, but this immunotherapy may well represent a simple, inexpensive, and active 'adjuvant' treatment.

Immunotherapy for gastric premalignant lesions and cancer.

Chronic atrophic gastritis, a precancerous change for gastric cancer, shows a loss of appropriate glands, Helicobacter pylori infection and autoimmune gastritis being the two main etiologic factors. While H. pylori eradication is the mandatory treatment for the former, no etiologic treatment is available for the latter, in which a Th1-type response, modulated by Tregs and Th17 cells, is involved. H. pylori-related atrophic gastritis is a risk factor for gastric adenocarcinoma, while autoimmune atrophic gastritis is also linked to a substantial risk of gastric type I carcinoid, related to the chronic stimulus exerted by hypergastrinemia on enterochromaffin-like cells. Several studies have been published on gastric cancer treatment through an active specific immunotherapy, aimed at improving the immunoregulatory response and increasing the circulating tumor-specific T cells. No study on immunotherapy of carcinoids is available but, in our experience, the administration of an antigastrin 17 vaccine induced carcinoid regression in two out of three patients treated.

An international multicenter randomized controlled trial of G17DT in patients with pancreatic cancer.

OBJECTIVES: This study aimed to investigate G17DT, an immunogen producing neutralizing antibodies against the tumor growth factors amidated and glycine-extended forms of gastrin-17, in the treatment of pancreatic cancer. METHODS: A randomized, double-blind, placebo-controlled, group-sequential multicenter trial of G17DT in patients with advanced pancreatic cancer unsuitable for or unwilling to take chemotherapy. Inclusion criteria were a Karnofsky performance score of 60 or higher and a life expectancy of more than 2 months. Patients received G17DT or placebo emulsion at weeks 0, 1, 3, 24, and 52. The primary end point was survival, and secondary end points were tolerability, Karnofsky performance. RESULTS: A total of 154 patients were recruited: 79 G17DT and 75 placebo. A final analysis of the intention-to-treat population, using a proportional hazards model, stratifying by disease stage and adjusting for interim analysis, gave a hazard ratio for mortality of 0.75 (95% confidence interval, 0.51-1.10, P = 0.138; G17DT/placebo). A conventional analysis without adjustment for disease stage or interim analysis, censoring for chemotherapy and excluding protocol violators, gave median survival periods of 151 (G17DT) and 82 days (placebo) (log-rank test, P = 0.03).Patients developing anti-G17DT responses (73.8%) survived longer than nonresponders or those on placebo (median survival, 176 vs 63 vs 83; log-rank test, P = 0.003). G17DT was well tolerated.

Gastrin inhibits a novel, pathological colon cancer signaling pathway involving EGR1, AE2, and P-ERK.

Human anion exchanger 2 (AE2) is a plasma membrane protein that regulates intracellular pH and cell volume. AE2 contributes to transepithelial transport of chloride and bicarbonate in normal colon and other epithelial tissues. We now report that AE2 overexpression in colon cancer cells is correlated with expression of the nuclear proliferation marker, Ki67. Survival analysis of 24 patients with colon cancer in early stage or 33 patients with tubular adenocarcinoma demonstrated that expression of AE2 is correlated with poor prognosis. Cellular and molecular experiments indicated that AE2 expression promoted proliferation of colon cancer cells. In addition, we found that transcription factor EGR1 underlies AE2 upregulation and the AE2 sequester p16INK4a (P16) in the cytoplasm of colon cancer cells. Cytoplasmic P16 enhanced ERK phosphorylation and promoted proliferation of colon cancer cells. Gastrin inhibited proliferation of colon cancer cells by suppressing expression of EGR1 and AE2 and by blocking ERK phosphorylation. Taken together, our data describe a novel EGR1/AE2/P16/P-ERK signaling pathway in colon carcinogenesis, with implications for pathologic prognosis and for novel therapeutic approaches.

G17DT: an antigastrin immunogen for the treatment of gastrointestinal malignancy.

G17DT (Gastrimmune) is an antigastrin-17 immunogen, raising antibodies that blockade gastrin-stimulated tumor growth. It has completed Phase III trials in patients with pancreatic cancer, and Phase III trials in gastric cancer are planned. Preclinical studies have confirmed that the G17DT-induced antibodies both reduce gastrin-17-stimulated gastric acid secretion and inhibit gastrin from interacting with the cholecystokinin-2 receptor. The efficacy of both passive and active immunization with G17DT has been established in a number of tumor systems, with additive effects demonstrated in combination chemotherapy in pancreatic, colon and gastric tumor models. Phase I/II studies in advanced gastrointestinal malignancies have shown no systemic or autoimmune reactions to active immunization with G17DT. The use of an optimized dose and dosing schedule has yielded a high proportion of antibody responders (70%), with minimal side effects and antibody titers measurable within 2 - 4 weeks. Phase II trials of G17DT in combination with chemotherapy have also been conducted in gastric and colorectal cancer. A Phase III, multicenter, double-blind, randomized, controlled trial of G17DT versus placebo in patients with advanced pancreatic cancer confirmed improved survival of patients in the G17DT group through an intention-to-treat analysis. The results of a randomized, double-blind, multinational, multicenter study of G17DT in combination with gemcitabine versus placebo and gemcitabine in patients with advanced pancreatic cancer failed to show improved overall survival except on subset analysis of patients with high antibody titers. Therefore, G17DT represents an emerging new modality for gastrointestinal malignancy.

Gastric inflammation, metaplasia, and tumor development in gastrin-deficient mice.

BACKGROUND & AIMS: Gastrin deficiency and proton pump inhibitor treatment cause achlorhydria, which predisposes to disease. To elucidate the underlying molecular biology, we examined the changes in gastric gene expression in both types of achlorhydria. We also explored the associated changes in the gastric microflora and the long-term consequences of gastrin-deficient achlorhydria. METHODS: Expression profiles were generated from gastric RNA from wild-type mice, gastrin knockout (KO) mice, gastrin KO mice after 1 week of gastrin infusion, and wild-type mice treated for 1 month with a proton pump inhibitor. The results were confirmed using real-time polymerase chain reaction and immunohistochemistry. Selective media were used to characterize the gastric microflora. RESULTS: The number of gastric bacteria was increased in both gastrin KO and PPI-treated mice. The expression profiles revealed activation of immune defense genes, interferon-regulated response genes, and intestinal metaplasia of the gastric mucosa. In young gastrin-deficient mice, gastrin infusions reversed the changes. Over time, the changes accumulated, became irreversible, and progressed into metaplasia and polyp development. Finally, the study showed that gastrin regulated the expression of genes encoding extracellular matrix proteins. CONCLUSIONS: Independently of gastrin, achlorhydria is associated with gastric bacterial overgrowth and intestinal gene expression patterns and is associated with predisposition to disease. Gastrin is therefore essential for prevention of gastric disease, mainly through control of acid secretion but to a lesser extent also through control of gastric gene expression. The gastrin-deficient mouse serves as a useful new model for gastric metaplasia and neoplasia.

Clinical experiences with G17DT in gastrointestinal malignancies.

The development of new agents for the treatment of gastrointestinal malignancies is increasing in pace and importance. The discovery of novel targets, namely the epidermal growth factor receptor and vascular endothelial growth factor, have sparked an explosion of new agents being tested in gastrointestinal malignancies. Clearly, novel agents and approaches are required. G17DT is a novel immunoconjugate designed to elicit a humoral response against the N-terminal end of G17 gastrin. In this overview, the authors summarize the clinical research focused on gastrointestinal tract cancers to date. In total, there is a clear signal of efficacy with this compound, although further testing is required in order for this efficacy to be demonstrated in a manner that will support regulatory approval.

What's new in pancreatic cancer treatment pipeline?

There is still a substantial need for the development of new treatments for patients with pancreatic cancer. In this chapter, we will document that there is quite a bit of an increase in research activity with development in two major areas including (1) agents in the pipeline which already have hints of antitumor activity in patients with pancreatic cancer (therapeutic monoclonal antibodies and vaccines as well as more conventional cytotoxics), and; (2) agents in the pipeline which have just started (or will soon start) in clinical trial. These agents range from a gene-therapy approach to radiation enhancement to inhibitors of protein with increased expression in the very hypoxic pancreatic cancer tissue, to new monoclonal antibodies. With the level of investigational activity in pancreatic cancer it is very likely that several new therapeutic approaches to the disease will be forthcoming.

The effect of jaundice on the generation of anti-gastrin antibodies in G17DT immunized patients with advanced pancreatic cancer.

AIM: The aim of this study was to determine the ability of G17DT to generate anti-gastrin antibodies in jaundiced patients with biliary obstruction due to advanced pancreatic cancer. METHODS: G17DT was administered to 41 patients with advanced pancreatic adenocarcinoma by intramuscular (i.m.) injection at a dose of 250mcg at weeks 0, 1 and 3 of the study. RESULTS: Thirty-five of 41 patients participating in the study were categorized as responders in terms of their gastrin-17 antibody response. There was no correlation between the maximum G17 antibody response and the bilirubin level at either week 0 or week 12. The median survival of patients from the time of the first injection of G17DT was 204 days with 25% of patients surviving for or=305 days. CONCLUSION: This study shows that G17DT administered to jaundiced patients with advanced pancreatic cancer is immunogenic and well tolerated.