RESUMEN
Pancreatic cancer has a low response rate to chemotherapy due to the low drug transferability caused by the low blood flow around the tumor. In the present study, focusing on nitric oxide (NO) for its vasodilatory and antitumor effects, a novel NO donor, a nitrated form of phenylbutyrate (NPB) was synthesized and the antitumor effect on human pancreatic cancer cells (AsPC1 and BxPC3) and xenografts was examined. Using Annexin V, NPB was confirmed to induce cell death against AsPC1 and BxPC3 in a time and concentrationdependent manner. In NPBexposed cells, DAFFM DA (a probe to detect intracellular NO) derived fluorescence was observed. Release of nitrite and nitrate from NPB in aqueous solution was very gradual until even 72 h after dissolution. Phenylbutyrate (PB) and hydroxy PB in which the nitro group of NPB was replaced with a hydroxyl group did not have the cell deathinducing effect as observed in NPB. These results suggest that the effect of NPB was dependent on NO release form NPB. Apoptosis inhibitor, ZVAD FMK, had no effect on the cell deathinducing effect of NPB, and NPB did not show significant activation of caspase3/7. In addition, NPB significantly decreased cellular ATP levels, suggesting that necrosis is involved in the effect of NPB. NPB also accumulated cells specifically at the S phase of the cell cycle. A single dose of NPB (10 mg/kg) into mice with established BxPC3 xenografts significantly suppressed tumor growth for at least 7 weeks without apparent toxicity. The findings of the present study indicate that NPB has potential as a novel therapeutic agent for NObased therapy of pancreatic cancer.
Asunto(s)
Neoplasias Pancreáticas , Fenilbutiratos , Animales , Apoptosis , Muerte Celular , Línea Celular Tumoral , Xenoinjertos , Humanos , Ratones , Nitratos/farmacología , Nitratos/uso terapéutico , Donantes de Óxido Nítrico/farmacología , Donantes de Óxido Nítrico/uso terapéutico , Neoplasias Pancreáticas/patología , Fenilbutiratos/farmacología , Ensayos Antitumor por Modelo de Xenoinjerto , Neoplasias PancreáticasRESUMEN
BACKGROUND/AIM: Nitric oxide (NO) has antitumor activity against various solid tumor cell types in addition to its vasodilatory effect. In the current study, we investigated the effect and mechanism of the synthetic nitrated form (NO2-NAT) of nateglinide, a hypoglycemic agent, on the induction of cell death in human pancreatic cancer cells. MATERIALS AND METHODS: NO production was evaluated by measuring nitrite (NO2) and nitrate (NO3) (NOx). Apoptotic cell numbers were determined using annexin V. RESULTS: NO2-NAT released nitrate and nitrite ions immediately upon dissolving in aqueous solution. NO2-NAT caused significant extracellular leakage of lactate dehydrogenase (LDH) in the human pancreatic cancer cell lines AsPC1 and BxPC3, and increased annexin-positive cells in a time- and concentration-dependent manner. NO2-NAT also significantly increased the activity of caspases 3 and 7. Exposure to Z-VAD-FMK, a caspase inhibitor, significantly suppressed NO2-NAT-induced cell death. CONCLUSION: These results indicated that NO2-NAT induces apoptosis in human pancreatic cancer cells and may serve as a new NO-based chemotherapeutic agent for the treatment of pancreatic cancer.