ABSTRACT
The study is designed to synthesize nano-carrier Tyr-RGD (cyclo-[Arg-Gly-Asp-d-Tyr-Lys]) and poly(ethylene glycol) modified polyethylenimine (Tyr-RGD-PEG-PEI) targeting vascular endothelial cells, then analyze its nanoparticle properties and the characteristics of drug carrying and targeting properties in vivo / in vitro tumor. The nano-carrier Tyr-RGD-PEG-PEI was synthesized with the method of chemical synthesis and the properties of this nanoparticle and drug carrying characteristics were identified. Its effect of targeting vascular endothelial cells in vitro was studied with the method of competitive binding assay. The fluorescent labeled nano-drug was injected into tumor-bearing nude mice to observe its tumor-targeting. The mean size of nano-carrier Tyr-RGD-PEG-PE was about 145 nm, good in encapsulation efficiency of siRNA. After incubation in plasma for half an hour, only about 3 percent of siRNA out. It was confirmed that it was a single spot with TLC analysis, the R(f) value was 0.65. Receptor competition experiments showed that the nano could effectively compete with RGD in binding the receptors on endothelial cells. Tumor-bearing nude mice experiments showed that when containing a fluorescent-labeled siRNA of Tyr-RGD-PEG-PEI nano-drug was injected into mice, after 24 hours this nano-drug mainly distributed within the tumor tissue. However, nano-drug without Tyr-RGD appeared in tumor tissue as well as other organs such as livers, lungs, etc. The Tyr-RGD-targeted gene vector Tyr-RGD-PEG-PEI synthesized in this study has good nanoparticle properties and high efficiency of gene-drug encapsulation. Study of nude mice shows that the ability of its tumor-targeting is significantly better than nano-drug without Tyr-RGD.
Subject(s)
Animals , Humans , Mice , Endothelial Cells , Metabolism , Gene Transfer Techniques , Genetic Vectors , Integrins , Mice, Nude , Nanoparticles , Oligopeptides , Pharmacology , RNA, Small InterferingABSTRACT
Objective: To study the effect of intracellular-free calcium and the expression of Fas and Fas L on the process of pancreatic carcinoma cell apoptosis. Methods: Apoptosis induced by 2 μmol/L arsenic trioxide in pancreatic cancer cell lines SW-1990 was investigated.Concentration of intracellular-free calcium （［Ca2+］i） was determined by Fura-2a fluorescein load technique. Fas and FasL were determined by flow cytometry. Results: Pancreatic cancer cells treated with 2 μmol/L arsenic trioxide presented apoptotic features: intact cell membrane, chromatin condensation, nucleic fragmentation and apoptotic body formation; agarose electrophoresis showed marked ladder; flow cytometery analysis showed a sub-G1 cell peak. In the process of pancreatic carcinoma cell apoptosis Fas and FasL and the ［Ca2+］i were significantly higher than that in the control. Conclusion: The pancreatic cancer cell apoptosis induced by arsenic trioxide is related to Fas and FasL expression by the cancer cells and the ［Ca2+］i increase in the cancer cells.
ABSTRACT
Objective: To select the telomerase positive cancer cell lines of gastrointestinal tract and to provide a convinced methodology for future telomerase study. Methods: Fifteen cancer cell lines (carcinoma of stomach 4, of liver 6, of pancreas 2, of colon 3) were cultured and telomerase activity were detected by TRAP-ELISA. The normal hepatic cells were taken as control. Results: Thirteen cell lines were telomerase positive in the 15 lines(86.7%). Conclusion: Most of gastrointestinal tract cancer lines express telomerase, indicating the detection of telomerase activity has clinical potential.
ABSTRACT
Objective: To study the effect of intracellular-free calcium and the expression of Fas and Fas L on the process of pancreatic carcinoma cell apoptosis. Methods: Apoptosis induced by 2 μmol/L arsenic trioxide in pancreatic cancer cell lines SW-1990 was investigated.Concentration of intracellular-free calcium （［Ca2+］i） was determined by Fura-2a fluorescein load technique. Fas and FasL were determined by flow cytometry. Results: Pancreatic cancer cells treated with 2 μmol/L arsenic trioxide presented apoptotic features: intact cell membrane, chromatin condensation, nucleic fragmentation and apoptotic body formation; agarose electrophoresis showed marked ladder; flow cytometery analysis showed a sub-G1 cell peak. In the process of pancreatic carcinoma cell apoptosis Fas and FasL and the ［Ca2+］i were significantly higher than that in the control. Conclusion: The pancreatic cancer cell apoptosis induced by arsenic trioxide is related to Fas and FasL expression by the cancer cells and the ［Ca2+］i increase in the cancer cells.
ABSTRACT
Objective: To select the telomerase positive cancer cell lines of gastrointestinal tract and to provide a convinced methodology for future telomerase study. Methods: Fifteen cancer cell lines (carcinoma of stomach 4, of liver 6, of pancreas 2, of colon 3) were cultured and telomerase activity were detected by TRAP-ELISA. The normal hepatic cells were taken as control. Results: Thirteen cell lines were telomerase positive in the 15 lines(86.7%). Conclusion: Most of gastrointestinal tract cancer lines express telomerase, indicating the detection of telomerase activity has clinical potential.