| ObjectiveIn this study,medium chain triglyceride(MCT)and triglyceride(TRIG)mixed lipids were used as the carrier materials to prepare gastric cancer vasculature targeted peptide GX1(CGNSNPKSC)modified paclitaxel-loaded and unmodified paclitaxel-loaded lipid carriers.And preparation properties and stability were evaluated.Subsequently,the antitumor activity of nano-lipid carriers were studied by in vitro and in vivo.MethodFirstly,polyethylene glycol 2000 was linked with stearic acid to form the intermediate polyethylene glycol monostearate,and then the carboxyl group was introduced into PEG terminal to obtain the carboxyl derivative of polyethylene glycol monostearate.Finally,the product was connected with GX1 cyclic peptide derived by amino acetic acid at the n-terminal,and the target product SA-PEG2000-GX1 was obtained.In order to obtain the optimal prescription of the nano-lipid carriers,the dosage or concentration of PTX,MCT,SA-PEG2000,TRIG and emulsifier were used as the inspection factors,and the Zeta potential,particle size,EE and DL of nanoparticles were used as the evaluation indexes.GX1-PTX-NLCs was prepared by replacing SA-PEG2000 with equivalent SA-PEG2000-GX1.Then the morphology of the nano-lipid carriers were observed by transmission electron microscopy,and the stability of those within 8d and in vitro release experiment were evaluated.CCK8 assay was used to investigate the inhibition of different concentrations of PTX and two kinds of nano-lipid carriers on Co-HUVEC and SGC7901 cells and toxicity of those on normal cells(GES-1 and HUVEC cells).In addition,the cellular uptake of nano-lipid carrier was qualitatively observed by confocal laser microscopy,and the effects of different concentrations and time on cell uptake were investigated.In this study,a xenograft model of human gastric cancer in nude mice was established.PTX,PTX-NLCs and GX1-PTX-NLCs were intravenously injected into tumor-bearing mice by tail vein every 3 days,5 times.and the body weight and tumor volume were measured.After 14 ds,tumors were isolated from each group,and the rest nude mice with tumot were left to observe and calculate the survival rate.ResultsThe structure of SA-PEG2000 and SA-PEG2000 carboxyl-derivant were verified by ~1H-NMR.The structure of GX1-PTX-NLCs was comfirmed by MALDI-TOF-MS.The results showed that the target product was synthesized successfully.The average particle size,Zeta potential,and drug loading of PTX-NLCs were190.37±3.78nm,-11.69±0.40mV,and 0.45±0.017%,respectively,while those of GX1-PTX-NLCs were 222.41±2.02nm,-9.89±0.37mV,and 0.40±0.013%,respectively,and the encapsulation rate of both NLCs reached above 80%.The TEM micrographs showed that the GX1-PTX-NLCs were spherical in shape.The PTX-NLCs and GX1-PTX-NLCs were stable within 8 ds.In vitro release study demonstrated that the slow-release effect of GX1-PTX-NLCs and PTX-NLCs were more obvious than paclitaxel.GX1-PTX-NLCs showed highest inhibition rate(31.59±0.30%)on Co-HUVEC cells and lowest cytotoxicity on GES-1 cells(18.54±0.64%)at 78 nmol/mL.Stronger storage capacity of GX1-mediated 6C nanoparticles were observed in Co-HUVEC cells.The cellular uptake study showed that the highest uptake rate(85.26±0.23%)of GX1-6C-NLCs in Co-HUVEC cells at 78 nmol/mL,3h.The tumor inhibition rate of GX1-PTX-NLCs reached 69.70±4.37%.By comparing the two nanoparticles,it was found that the anti-tumor activity of GX1-PTX-NLCs was better than that of free PTX and PTX-NLCs in vivo studies.Meanwhile,two NLCs also prolonged the survival time of mice.H&E staining showed that GX1-PTX-NLCs had the most serious damage to tumor tissue.ConclusionIn this study,GX1-PTX-NLCs was successfully synthesized with high encapsulation rate and good stability.On the other hand,the results of in vitro and in vivo experiments showed that GX1-PTX-NLCs had excellent anti-tumor effect and low toxicity.These results demonstrated that GX1-PTX-NLCs is a potentially efficient targeted drug delivery system. |
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