Resveratrol induces apoptosis in pancreatic cancer cells.

BACKGROUND: Pancreatic cancer is one of the most lethal human cancers with a very low survival rate of 5 years. Conventional cancer treatments including surgery, radiation, chemotherapy or combinations of these show little effect on this disease. Several proteins have been proved critical to the development and the progression of pancreatic cancer. The aim of this study was to investigate the effect of resveratrol on apoptosis in pancreatic cancer cells. METHODS: Several pancreatic cancer cell lines were screened by resveratrol, and its toxicity was tested by normal pancreatic cells. Western blotting was then performed to analyze the molecular mechanism of resveratrol induced apoptosis of pancreatic cancer cell lines. RESULTS: In the screened pancreatic cancer cell lines, capan-2 and colo357 showed high sensitivity to resveratrol induced apoptosis. Resveratrol exhibited insignificant toxicity to normal pancreatic cells. In resveratrol sensitive cells, capan-2 and colo357, the activation of caspase-3 was detected and showed significant caspase-3 activation upon resveratrol treatment; p53 and p21 were also detected up-regulated upon resveratrol treatment. CONCLUSION: Resveratrol provides a promising anti-tumor strategy to fight against pancreatic cancer.

[Establishment of red fluorescent protein orthotopic transplantation nude mice metastasis model of pancreatic cancer and whole-body fluorescent imaging].

OBJECTIVE: To establish a stable high red fluorescent protein (RFP)-expressing orthotopic transplantation nude mice spontaneous metastasis model of pancreatic cancer. METHODS: Stable high RFP-expressing cells SW1990-RFP were injected subcutaneously into mice to establish subcutaneous implantation model. Fluorescent tumor piece from subcutaneous was transplanted into the body of the pancreas to establish surgical orthotopic implantation model. The growth of primary tumor, metastasis and micrometastasis were assessed by whole-body fluorescence imaging system. RESULTS: Twelve RFP orthotopic transplantation nude mice metastasis models of pancreatic cancer were established successfully, the percentage of success rate was 100%. RFP-labeled pancreatic cancer growth could be monitored in real time way. The micrometastasis of primary lesions were detected in early stage with whole-body fluorescence imaging system. CONCLUSIONS: The RFP orthotopic transplantation nude mice metastasis model of pancreatic cancer is stable and reliable, and can be observed dynamically in vitro in a noninvasive way, with much higher sensitivity and specificity.

hTERT-targeted E. coli purine nucleoside phosphorylase gene/6-methylpurine deoxyribose therapy for pancreatic cancer.

BACKGROUND: Pancreatic cancer is one of the most common tumors and has a 5-year survival for all stages of less than 5%. Most patients with pancreatic cancer are diagnosed at an advanced stage and therefore are not candidates for surgical resection. In recent years, investigation into alternative treatment strategies for this aggressive disease has led to advances in the field of gene therapy for pancreatic cancer. E. coli purine nucleoside phosphorylase/6-methylpurine deoxyribose (ePNP/MePdR) is a suicide gene/prodrug system where PNP enzyme cleaves nontoxic MePdR into cytotoxic membrane-permeable compounds 6-methylpurine (MeP) with high bystander activity. hTERT is expressed in cell lines and tissues for telomerase activity. In this study we examined the efficacy of ePNP under the control of hTERT promoter sequences and assessed the selective killing effects of the ePNP/prodrug MePdR system on pancreatic tumors. METHODS: Recombinant pET-PNP was established. The protein of E. coli PNPase was expressed and an antibody to E. coli PNPase was prepared. Transcriptional activities of hTERT promoter sequences were analyzed using a luciferase reporter gene. A recombinant phTERT-ePNP vector was constructed. The ePNP/MePdR system affects SW1990 human pancreatic cancer cell lines in vitro. RESULTS: The hTERT promoter had high transcriptional activity and conferred specificity on cancer cell lines. The antibody to E. coli PNPase was demonstrated to be specific for the ePNP protein. The MePdR treatment induced a high in vitro cytotoxicity on the sole hTERT-ePNP-producing cell lines and affected SW1990 cells in a dose-dependent manner. CONCLUSIONS: The hTERT promoter control of the ePNP/MePdR system can provide a beneficial anti-tumor treatment in pancreatic cancer cell lines including a good bystander killing effect.

[Nuclear factor-kappaB expression in peripheral blood polymorphonuclear leukocytes of patients with acute pancreatitis and the preventive effectiveness of pyrrolidine dithiocarbamate on NF-kappaB in vitro].

OBJECTIVE: To investigate the expression of NF-kappaB in peripheral blood polymorphonuclear leukocyte (PMN) of acute pancreatitis (AP) and to assess the preventive effectiveness of pyrrolidine dithiocarbamate (PDTC) on NF-kappaB in vitro. METHODS: Nineteen patients and 16 healthy individuals as control were enrolled in this study. The expression of NF-kappaB in PMNs was determined by gel electrophoretic mobility shift assay (EMSA). Routine clinical examination results and computed tomography findings of AP were recorded in all patients. RESULTS: The PMNs from the patients with AP showed higher levels of NF-kappaB activities than those from control subjects (P < 0.01), severe acute pancreatitis (SAP) group showed much higher than mild acute pancreatitis (MAP) group (P < 0.05). In vitro, PDTC could reduce the NF-kappaB activity in PMNs of patients with AP, and its effectiveness at 2 mmol/L was stronger than at 1 mmol/L (P < 0.05). The PMNs from control subjects pretreated with 2 mmol/L PDTC before stimulation with the plasma from patients with SAP showed lower levels of NF-kappaB activities than did those untreated (P < 0.05). CONCLUSION: The NF-kappaB activation in peripheral blood PMNs participate in the course of acute pancreatitis and can be inhibited by PDTC in vitro.

Relationship between telomerase activity and its subunit expression and inhibitory effect of antisense hTR on pancreatic carcinoma.

AIM: To directly investigate the relationship between telomerase activity and its subunit expression and the inhibitory effect of antisense hTR on pancreatic carcinogenesis. METHODS: We examined the telomerase activity and its subunit expression by cell culture, polymerase chain reaction (PCR), PCR-silver staining, PCR-ELISA, DNA sequencing, MTT and flow cytometry methods. RESULTS: PCR-silver staining and PCR-ELISA methods had the same specificity and sensitivity as the TRAP method. Telomerase activity was detected in the extract of the 10(th),20(th) and 30(th) passages of P3 cells,while it was absent in fibroblasts. Furthermore, after the 30th generation, the proliferation period of fibroblast cells was significantly prolonged. Telomerase activity and hTERTmRNA were detected in two pancreatic carcinoma cell lines, but were found to be negative in human fibroblast cells. Telomerase activity and hTERTmRNA were tested in pancreatic carcinoma specimens of 24 cases. The telomerase activity was positive in 21 of the 24 cases (87.5 %), and the hTERTmRNA in 20 cases (83.3 %). In adjacent normal tissues positive rates were both 12.5 %. There was a significant difference between the two groups. This indicated a significant correlation between the expression level of telomerase activity and histologic differentiation, metastasis and advanced clinical stage of pancreatic carcinoma. Our findings showed that the expressions of hTR and TP1mRNA were not correlated with the activity of telomerase but the expression of hTERTmRNA was. After treatment with PS-ODNs, telomerase activity in P(3) cells weakened and the inhibiting effect became stronger with an increase in PS-ODNs concentration. There was a significant difference between different PS-ODN groups (P<0.05). Inhibition of telomerase activity occurred most significant with PS-ODN1. The results of the FCM test of pancreatic cancer P(3) cells showed an increase in the apoptotic rate with increasing PS-ODN1 and PS-ODN2 concentrations. CONCLUSION: The expression of telomerase activity has a significant relationship to carcinogenesis. A strong correlation exists between telomerase activity and hTERTmRNA expression. The up-regulation of hTERTmRNA expression may play a critical role in human carcinogenesis. The expression of telomerase activity and its subunit level in pancreatic carcinoma significantly correlate with the clinical stage of pancreatic carcinoma and hence, may be helpful in its diagnosis and prognosis. The anti-hTR complementary to the template region of hTR is sufficient to inhibit P3 cell telomerase activity and cell proliferation in vitro, and can lead to a profound induction of programmed cell death.

[Inhibition effects of phosphorothioate-modified antisense hTR on the telomerase activity and the growth of P3 cells derived from pancreatic cancer in culture].

This paper is to investigate PS-ODN's (antisense-PS-ODN of hTR,sense-PS-ODN of hTR and random sequence) effects on telomerase activity and proliferation of P3 pancreatic cancer cells,and to find a novel method for gene therapy of pancreatic cancer. The results indicate that the anti-hTR complementary to the template region of hTR is sufficient to inhibit P3 cell telomerase activity and cell proliferation in vitro,and as a result, they can lead to a profound induction of programmed cell death. Telomerase represents an interesting and promising anticancer drug target and anti-telomerase technology may have potential significance in tumor therapy.