[Toxicity of cationic liposome Lipofectamine 2000 in human pancreatic cancer Capan-2 cells].

OBJECTIVE: To investigate the toxicity of cationic liposome Lipofectamine 2000 (Lipo) in human pancreatic cancer Capan-2 cells. METHODS: Capan-2 cells were cultured in the presence of Lipo at toxic concentrations, and the cell growth, apoptosis and cell cycle changes were evaluated by cell counting and flow cytometry. RESULTS: The concentrations of both Lipo and siRNA affected the transfection efficiency. In a transfection volume of 2 ml, the presence of 5 microl Lipo resulted in slowed growth of Capan-2 cells, which was especially obvious after 3 days (P<0.001). Prolonged culture of the transfected cells caused significant increases in early apoptotic cells (P<0.05) and in the damaged or necrotic cells (P<0.001), and resulted in reduced viable cells (P<0.01); these changes became obvious after a 48-hour culture, which also increased the ratio of G(0)/G(1) phase cells (P<0.05) and decreased those of G(2)/M phase cells (P<0.01), S phase cells (P<0.01), and the late apoptotic cells (P<0.05). CONCLUSION: Toxic concentrations of Lipo can affect the growth, apoptosis and cell cycles of Capan-2 cells in vitro, and this urges careful concentration selection when using Lipo for gene transfer into different cells.

[Biodistribution of (99m)Tc-labeled anti-VEGF mAb 5-FU loaded polylactic acid nanoparticles in human gastric carcinoma xenografts].

OBJECTIVE: To prepare (99m)Tc-labeled Anti-VEGF mAb 5-FU loaded polylactic acid nanoparticles ((99m)Tc-Ab-5-FU-NPs) and investigate its biodistribution in human gastric carcinoma xenografts. METHODS: (99m)Tc-Ab-5-FU-NPs were prepared by labeling Ab-5-FU-NPs with (99m)Tc using improved Schwarz method. After isolation of (99m)Tc-Ab-5-FU-NPs using SephadexG250 column, the labeling ratio and radiochemical purity were determined using chromatography. The immunocompetence of (99m)Tc- Ab-5-FU-NPs was detected by ELISA and immunohistochemistry. (99m)Tc-Ab-5-FU-NPs were then injected via the tail vein into SCID mice bearing human gastric carcinoma, and (99m)Tc labeled mice-derived monoclonal IgG loaded polylactic acid nanoparticles were used as the control, followed by radioimmunoscintigraphic imaging at 2 and 6 h. The radioactive count and radioactive ratio of the tumor and non-tumor tissue (T/NT) in the animal models were calculated using ROI technique. After imaging at 24 h, SCID mice were sacrificed and the radioactive distribution, the %ID/g, as well as the T/NT radioactive ratio were examined, respectively. The concentrations of 5-FU in the tumor and blood were also detected using HPLC method. RESULTS: The labeling ratio of (99m)Tc-Ab-5-FU-NPs was 90%-95%. (99m)Tc-Ab-5-FU-NPs were detected in the tumor tissues by radioimmunoimaging 2 h after the injection. ID%/g in the tumor tissues at 2 and 6 h were both significantly higher than that of the control group. Both the ID%/g in tumor tissues and radioactive ratio of tumor and blood at 6 h were higher than those at 2 h, and the concentration of 5-FU in experimental group increased continuously with time and was significantly higher than that in control group. CONCLUSIONS: (99m)Tc-Ab-5-FU-NPs prepared in this study can meet the demands of radioimmunoimaging, and the anti-VEGF monoclonal antibody possesses reliable immune targeting ability. Six hours after injection, (99m)Tc-Ab-5-FU-NPs can specifically accumulate in the tumor tissues in human gastric carcinoma xenografts at high concentration.

[Study of the anti-tumor effect of anti-vascular endothelial growth factor McAb 5-fluorouracil loaded polylactic acid nanoparticles].

OBJECTIVE: To explore the anti-tumor efficacy of anti- vascular endothelial growth factor (VEGF) McAb 5-fluorouracil (5-FU) loaded polylactic acid (PLA) nanoparticles (NPS) in human gastric carcinoma xenografts of nude mice. METHODS: Anti-VEGF McAb 5-FU loaded PLA NPS were made by ultrasound emulsification. Nude mice model of human gastric carcinoma xenografts was established. Therapeutic effects of drugs on human gastric carcinoma xenografts and side effects concerned were observed. RESULTS: The tumor inhibition rates of control group, nanosphere without 5-FU group, 5-FU (20 mg/kg) group, anti-VEGF McAb nanosphere without 5-FU group, anti-VEGF McAb group, nanosphere with 5-FU group, 5-FU (20 mg/kg) combined with anti-VEGF McAb group, anti-VEGF McAb 5-FU loaded nanosphere group was 0, 6.61%, 24.26%, 27.94%, 35.29%, 37.50%, 39.71% and 52.21% respectively, and there were no significant differences between anti-VEGF McAb 5-FU loaded nanosphere group and nanosphere group without 5-FU in WBC count, serum alanine transferase level or creatinine level. Compared with control group and anti-VEGF McAb 5-FU loaded nanosphere group, the 5-FU group decreased by 34.43% and 37.38% respectively in WBC count (P< 0.05), and increased by 93.17% and 66.56% respectively in alanine transferase. There were significant differences between experimental groups and control group in apoptosis index, especially between anti-VEGF McAb 5-FU loaded nanosphere group and control group (P< 0.05). The microvessel density (MVD) of experimental groups containing anti-VEGF McAb was significantly lower than that of control group or groups containing 5-FU (P< 0.05). CONCLUSION: Anti-VEGF McAb 5-FU loaded nanosphere can increase the tumor inhibitory rate of 5-FU, induce apoptosis by inhibiting tumor angiogenesis with less side effect, and then enhance therapeutic effect, which indicate its potential as a novel, safe nano-tumor-targeting drug.

[Preparation and release efficiency of polylactic acid nanoparticle].

BACKGROUND & OBJECTIVE: As a new drug delivery carrier, medical nanoparticle (NP) appears to be very promising and are widely studied. Compare with microparticle, nanoparticle possesses several advantages, such as ultramicroscopic size, could be ingested by the cells after crossing the tissue matrix, and can penetrate the arterial wall and cross the blood-brain barrier. This study was to prepare polylactic acid (PLA) nanoparticle, and observe its morphology, diameter, structure, surface elements, and ability of in vitro drug release. METHODS: The biodegradable PLA was used as the carrier, and 5-fluorouracil (5-FU) was used as the model drug. 5-FU-PLA nanoparticle (5-FU-PLA-NP) was prepared by matrix and ultrasound emulsification. Morphology of 5-FU-PLA-NP was observed under scanning electron microscope; its surface elements were detected by X ray photoelectron spectroscopyû its drug loading (DL), embedding ratio (ER), and ability of in vitro drug release were assessed by ultraviolet spectroscopy. RESULTS: The nanoparticle was uniformly spherical with average diameter of (191+/-17) nm, DL of 15.2%, and ER of 45.6%. The nanoparticle showed sustained release character in the experiment of in vitro drug release: the cumulative drug release rate in analog body fluid was 94.3% at the 10th day. CONCLUSION: PLA-NP may serve as a carrier of 5-FU, and can change the pharmacokinetics of 5-FU, slower down drug release; 5-FU-PLA-NP can be prepared as intravenous injection, and may prolong the in vivo circulation time of 5-FU, so as to play more efficient antitumor effects.