z-360 and gastrin-17

The aim of the study was to evaluate the anti-tumor mechanism of Z-360, a gastrin/cholecystokinin-2 receptor (CCK2R) antagonist, in MIA PaCa-2 cells and in a subcutaneous xenograft mice model.. The anti-tumor effects of Z-360 and/or gemcitabine were monitored using a MIA PaCa-2 xenograft model. The effect of Z-360 on apoptosis in the model was examined by TUNEL staining and real-time PCR analysis and the effect in MIA PaCa-2 cells stably expressing human CCK2R was also evaluated by caspase-3/7 activity.. In this xenograft model, Z-360 significantly reduced the tumor weight, increased TUNEL-positive cells and suppressed the expression of anti-apoptosis factors such as survivin, XIAP and Mcl-1, and these effects of Z-360 combined with gemcitabine were more effective. Furthermore, gastrin-17 and gastrin-34 inhibited apoptosis in vitro and Z-360 dose-dependently abrogated this effect.. These results suggest that Z-360 exerts an anti-tumor effect through a reduction in anti-apoptosis factors by blocking CCK2R.

Topics: Animals; Apoptosis; Benzodiazepinones; Cell Line, Tumor; Cell Proliferation; Deoxycytidine; Endopeptidases; Gastrins; Gemcitabine; Gene Expression Regulation, Neoplastic; Humans; Inhibitor of Apoptosis Proteins; Mice; Myeloid Cell Leukemia Sequence 1 Protein; Pancreatic Neoplasms; Receptor, Cholecystokinin B; Survivin; X-Linked Inhibitor of Apoptosis Protein; Xenograft Model Antitumor Assays

Gastrin is known to enhance the growth of pancreatic carcinoma via the cholecystokinin (CCK)-2/gastrin receptor. We investigated the anti-tumor effect of Z-360 (calcium bis [(R)-(-)-3-[3-{5-cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b][1,4]diazepin-3-yl}ureido]benzoate]), a novel orally active CCK-2 receptor antagonist alone or combined with the chemotherapeutic agent, gemcitabine in human pancreatic adenocarcinoma cell lines.. Z-360 potently inhibited specific binding of [3H]CCK-8 to the human CCK-2 receptor, with a Ki value of 0.47 nmol/l, and showed antagonistic activity for this receptor. The anti-tumor effect of Z-360 alone or combined with gemcitabine was assessed using subcutaneous xenografts of MiaPaCa2 and PANC-1 and an orthotopic xenograft model (PANC-1). Oral administration of Z-360 significantly inhibited the growth of MiaPaCa2 (41.7% inhibition at 100 mg/kg, P<0.01). Combined administration of Z-360 and gemcitabine significantly inhibited subcutaneous PANC-1 tumor growth compared with either agent alone (27.1% inhibition compared to effect with gemcitabine, P<0.05), and significantly prolonged survival compared with the vehicle control (median survival of 49 days in vehicle compared to 57 days in the combination group, P<0.05). In vitro studies showed that Z-360 significantly inhibited gastrin-induced proliferation of human CCK-2 receptor-expressing cells, and also significantly reduced gastrin-induced PKB/Akt phosphorylation to the level of untreated controls.. In the present study, we have shown that Z-360 combined with gemcitabine can inhibit pancreatic tumor growth and prolong survival in a pancreatic carcinoma xenograft model, on a possible mode of action being the inhibition of gastrin-induced PKB/Akt phosphorylation through blockade of the CCK-2 receptor. Our results suggest that Z-360 may be a useful adjunct to gemcitabine for the treatment of pancreatic carcinoma and a therapeutic option for patients with advanced pancreatic cancer.

Topics: Adenocarcinoma; Administration, Oral; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Benzodiazepinones; Cell Line, Tumor; Cell Proliferation; Deoxycytidine; Disease Models, Animal; Female; Gastrins; Gemcitabine; Humans; Mice; Mice, Nude; Pancreatic Neoplasms; Phosphorylation; Proto-Oncogene Proteins c-akt; Receptor, Cholecystokinin B; Survival Rate; Xenograft Model Antitumor Assays