Preparation,Characterization And Anti-breast Cancer Evaluation Of In Vitro And In Vivo Folate Motified L-K6 Antimicrobial Peptide-liposomal Drug System

Tumor-targeting liposomes as carrier for anti-tumor drugs have gained extensive attention.Among them,folic acid(FA)-containing liposomes can permit durg to interact selectively with tumor cells,through specific interactions between FA and folate receptor,which have been reported to be abundantly expressed in tumor cells surface.Cationic antimicrobial peptides(CAPs)are another research focus of current anti-tumor drug research because of their unique mechanisms of action and significant tumor cell selectivity.CAP L-K6 contains 13 amino acid residues and 7 net positive charges,and normally forms α-helix secondary structure.L-K6 can selectively inhibit the proliferation of a variety of malignant tumor cells,while shows relatively weak cytotoxicity to normal mammalian cells.However,due to the rapid hydrolysis and poor stability in vivo,the application of CAPs for anticancer therapy is limited.Therefore,the present study aims to establish a novel anticancer drug carrier system by using FA-containing tumor-targeting L-K6 liposomes(FA-L-K6-LIP).The physical and chemical properties,stability,in vitro and in vivo anti-cancer activities were further evaluated.FA-L-K6-LIP was prepared by pre-insertion and post-extrusion methods.The best encapsulation rate was determined to confirm that post-extrusion as the best prepare protocol.We further characterized the FA-L-K6-LIP system.Our data showed that the encapsulation efficiency of FA-L-K6-LIP was(48.11 ± 1.29)%,the particle size was(98.86 ± 0.66)nm and the zeta potential was(-8.56 ± 1.05)mv.The transmission electron microscope observation revealed a sphere shape.Next,drugs contents in(FA-L-K6-LIP)were analyzed at different time points by high performance liquid chromatography(HPLC).Drugs content at 24 h and 48 h after FA-L-K6-LIP preparation was 85% and 75% respectively,suggesting a better stability of FA-L-K6-LIP system.Moreover,while FA-L-K6-LIP was incubated with 50% serum for 12 h,24 h and 36 h,their particle size was maintained at around 100 nm,indicating a good biostability.All these data may provide a good basis for biological function anlysis.Finally,we preliminarily evaluated the antitumor activity and tumor-targeting property of FA-L-K6-LIP both in vitro and in vivo.The MTT assay showed that FA-L-K6-LIP exerted a good anti-cancer effect against human breast cancer MCF-7 cells.FA-L-K6-LIP was uptaken effectively by MCF-7 cells,and showed similar antitumor activity as L-K6 after 24 h,indicating that the FA-L-K6-LIP system remained the selective anti-cancer effect of L-K6.Near-infrared fluorescence(NIRF)imaging showed that FA-L-K6-LIP had the stronger fluorescence intensity in tumor region than non-tumor regions of MCF-7-bearing nude mice,confirming the trend of FA-L-K6-LIP to actively target to the tumor site.Moreover,FA-L-K6-LIP also showed a more distribution in tumor regions and exerted stronger anticancer activity than L-K6-LIP,without significant impact on the general status of mice.In summary,FA-L-K6-LIP established in the present study showed a good stability,and exerted a selective anti-tumor effect and showed tumor-targeting property both in vivo and in vitro.All these findings provided important experimental evidence for the future research of peptidic anticancer drug preparation and its clinical application.