Applications Of Gemcitabine-loaded Albumin Nanoparticles In The Treatment Of Pancreatic Cancer And In The Regional Intra-arterial Infusion Of Pancreas: Experimental Studies

Objective:This study was conducted to prepare serum albumin nanoparticles loaded with gemcitabine(GEM),detect their efficacy and safety in the treatment of pancreatic cancer and in the regional intra-arterial infusion of pancreas,and provide experimental evidence of GEM-loaded albumin nanoparticles’ advantage in pancreat -ic cancer chemotherapy,particulaly regional intra-arterial infusion chemotherapy.Methods:①Two types of bovine serum albumin GEM-loaded nanoparticles (GEM-NP),mean diameters of 110nm and 406nm,were prepared with modified desolvation cross-linking method.And the size distributions,drug loadings,drug encapsulation rates,in-vitro drug releases,of the GEM-NPs were detected.②110nm GEM-loaded albumin nanoparticles(110nm-GEM-NP),406um GEM-loaded albumin nanoparticles(406um-GEM-NP) and pure GEM were injected into SD rats via femoral veins,then the concentrations of GEM in the blood plasma and several organs were detected by high-performance liquid chromatography.And the safety of the GEM-NPs were proven by blood routine test,liver and kidney function test,and histological observation.③The anticancer activity in vitro of GEM-NPs on the pancreatic cancer cell lines,BXPC-3,PANC-1,SW1990 and CFPAC-1,were detected with MTT assay and flow cytometry.④The anticancer activity in vivo of GEM-NPs were evaluated in PANC-1 xenografts in nude mice.Cell proliferation and apoptosis were assessed using Ki-67 immunohistochemistry method and TUNEL method.Bcl-2 and Bax,apoptosis related genes,were detected by RT-PCR technique.⑤Regional intra-arterial infusion of GEM-NPs to beagle dogs’ pancreas was performed,with the concentrations of GEM in the blood plasma and organs detected by high-performance liquid chromatography,and the targeting effect and superiority of GEM-NPs in the regional intra-arterial infusion to pancreas evaluated.Results:①Two types of bovine serum albumin GEM-loaded nanoparticles,mean diameters of 110nm and 406nm,were prepared.Both 110nm-GEM-NP and 406nm-GEM-NP were well-dispersed,of moderately uniform size distribution,and of good stability,and had smooth surfaces.Drug loadings were 11.25%and 13.40%; drug encapsulation rates were 82.92%and 92.56%;in-vitro drug release times were 8 and 12 hours respectively.②The experiments of SD rats indicated that GEM-NPs, comparing with GEM,had lower hydrophilicity,better deposition effect in tissues, with good biocompatibility and safety,without additional side effects.Particularly, 406nm-GEM-NP had high concentration in pancreas,spleen and liver,with lower toxic reaction.Meanwhile,110nm-GEM-NP had no obvious targeting effect.③In vitro cytotoxicity assay in pancreatic cancer cells indicated significant anti-proliferation effect of GEM-NPs,especially 406nm-GEM-NP,which had higher inhibitory effect than GEM at some dosages.Blank albumin nanoparticles had good biocompatibility in vitro.④The experiments in nude mice indicated that the better antitumor effect against pancreatic cancer xenografts was achieved by 406nm-GEM-NP,including inhibition of tumor growth,prevention of liver metastasis, increase of cell apoptosis,decrease of cell proliferation,regulation of Bcl-2 and Bax, which were more significant comparing with GEM.Meanwhile,110nm-GEM-NP had lower antitumor effect than 406nm-GEM-NP or GEM.GEM-NPs had low toxic reaction with good biocompatibility.⑤The experiment of beagle dogs indicated that GEM concentration in pancreas,spleen,liver,peripheral and portal vein blood,were significantly higher after intra-arterial infusion with 406nm-GEM-NP,comparing with GEM;and 406nm-GEM-NP had excellent targeting effect,slow-release,good biocompatibility and safety.Conclusion:406nm-GEM-NP have good antitumor effects against pancreatic cancer in vitro and in vivo,with high concentration in pancreas,spleen and liver,with low toxic reaction and good biocompatibility.Intra-arterial infusion chemotherapy with 406nm-GEM-NP for pancreatic cancer could increase targeting effect and slow-release effect,and could reduce toxic reaction or side effect.