RESUMO
OBJECTIVES: The aim of this study was to evaluate whether the CCK-C receptor, a splice variant of the CCK-B receptor, in human pancreatic cancer cells was associated with accelerated cancer cell growth. METHODS: In vitro, BxPC-3 cells were transfected with the antisense cDNA for the CCK-C receptor and growth of transfected cells was compared with that of wild-type (WT) and empty vector (EV)-transfected cells; expression was confirmed by RT-PCR and immunocytochemistry. In vivo, athymic nude mice bearing human BxPC-3 pancreatic cancers were treated for 28 days with either an antisense oligonucleotide specific to the CCK-C receptor, the same nucleotide sequence arranged in a scrambled fashion (nucleotide control), or vehicle (control). RESULTS: In culture, BxPC-3 cells transfected with the antisense cDNA for the CCK-C receptor were reduced in cell number 65% compared with WT and EV-transfected cell cultures at 6 days; this difference was statistically significant (P = 0.002). Transfected cells did not respond to exogenous gastrin with growth as did WT cells. Tumors of mice treated with the antisense oligonucleotide for CCK-C were 75% smaller in volume and 83% reduced in weight (P = 0.03) compared with the control tumors. CONCLUSION: These studies indicate that the CCK-C receptor is functional and plays a crucial role in growth of human pancreatic cancer.
Assuntos
Neoplasias Pancreáticas/patologia , Receptores da Colecistocinina/fisiologia , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , DNA Antissenso/genética , DNA Complementar/genética , DNA de Neoplasias/genética , Humanos , Camundongos , Camundongos Nus , Transplante de Neoplasias/métodos , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/farmacologia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Receptores da Colecistocinina/genética , Receptores da Colecistocinina/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Transfecção/métodosRESUMO
Opioid growth factor (OGF) is an endogenous pentapeptide that inhibits growth of human pancreatic cancer cells in culture, as well as xenografts in nude mice. To establish the maximum tolerated dose (MTD), and determine safety and toxicity of OGF, a phase I trial was performed in patients with advanced unresectable pancreatic cancer. Patients with unresectable pancreatic adenocarcinoma were treated with escalating doses of OGF for 30 min i.v. to determine the MTD. The s.c. route of administration also was evaluated. Once the MTD was established, a group of patients was treated chronically, and monitored for safety and toxicity. Hypotension was the dose-limiting toxicity, resulting in a MTD of 250 microg/kg i.v. Due to limited solubility of OGF in small volumes, a maximum dose of 50 microg/kg twice daily was determined by the s.c. route of administration. No adverse events were reported for oxygen saturation, cardiac rhythm, laboratory values or neurological status in either the acute or chronic parts of the study with the i.v. or s.c. routes. During the chronic i.v. phase, two subjects had resolution of liver metastases and one showed regression of the pancreatic tumor. Mean survival from the time of diagnosis was 8.7 months (range 2-23 months) in the i.v. group and 9.5 months (range 1-18 months) in the s.c. group. We conclude that OGF can be safely administered to patients with advanced pancreatic cancer. Further studies are needed to determine the efficacy of OGF alone or in combination with present modes of therapy for the treatment of pancreatic cancer.