Paclitaxel-loaded Peptide Nanoparticle Targeting To Breast Cancer Cells Shows Anti-cancer Capability

Objective:Breast cancer is the most threatening disease to women.Deliver the drugs directly to the infection spot has been improving efficacy of the treatments.In our lab,we found a peptide PI could specifically target to a type of breast cancer cells.In this project,we conjugated peptide PI to the paclitaxel-loaded nanoparticle and delivered it to the target cancers and evaluated the treatment effects against MDA-MB-231 cells in vivo and in vitro.Methods:Paclitaxel loaded PLGA nanoparticles (PTX-NPs) were made by the solvent evaporation technique, then use EDC/NHS crosslinking agents to conjugate FITC labeled PI to the surface of PTX-NPs, named PPTX-NPs. Using the same method, Coumarin-6 as a fluorescent probe was conjugated to the nanoparticles, Coumarin-6-NPs; and FITC labeled peptide TAT conjugated PTX-NPs (TPTX-NPs) were prepared.The sizes and morphologies of those nanoparticles were assessed by SEM. Drug loading, EE and cumulative release were measured by HPLC. The connection between peptides and nanoparticles was evaluated by Fourier transform infrared (FTIR).Cell killing experiment:MDA-MB-231 cells and TCA-8113 cells were treated with coumarin-6-NPs, PTX-NPs,PPTX-NPs and TPTX-NPs separately, then the uptake of those nanoparticles by cells was detected by a microscope at 12h and 24h. The anti-proliferation efficiency of those nanoparticles was measured by MTS assay.Pharmacokinetics and anti-tumor activity:PTX, PTX-NPs and PPTX-NPs were used to treat tumor-bearing nude mice, while normal saline was used as a control. The pharmacokinetics were measured by getting blood from the heart over different time periods after tail vein injection. The inhibitory effect was evaluated by comparing the sizes of the tumors.Results:PPTX-NPs and PTX-NPs were little larger than blank-NPs.PPTX-NPs gathered together partly.HPLC measurement further showed the drug loading of PPTX-NPs were 8.4±0.59%, while the cumulative release for 2 days and 12 days were 32% and 58%, respectively. Fluorescent images demonstrated PPTX-NPs and TPTX-NPs were both well took in by MDA-MB-231 cells at 12h and 24h, the former was 80% and 95%,while the latter was 60% and 75%,respectively,whereas the uptake of PPTX-NPs was lower than TPTX-NPs in TCA-8113 cells.TCA-8113 cells hardly uptook PPTX-NPs,but almost 57% and 80% TCA-8113 cells can uptake TPTX-NPs at 12h and 24h.MTS assay indicated PPTX-NPs had superior cytotoxicity to MDA-MB-231 cells with cell survival rate to be 56.04±0.86% at 24 hours and34.80±0.60% at 48 hours,which was lower than PTX-NPs with cell survival rate to be 60.65±0.49% at 24h and 45.5±0.81% at 48h(P<0.05).In vivo experiment:the pharmacokinetics showed that the half-life t1/2 of PPTX-NPs was 2.1 times of PTX and its AUC0→24h was 4.24 times of PTX. There was statistical differences between PPTX-NPs and PTX(P<0.05).The tumor inhibitory effects of PTX, PTX-NPs, PPTX-NPs were 25.8%,62.9% and 85.5%, respectively (P<0.05).Conclusion:Breast cancer specific peptide (PI) conjugatedPaclitaxel-loaded PLGA nanoparticles (PPTX-NPs) had specific targeting characteristcs and safty.They can facilitate drugs into MDA-MB-231 cells and improve their targeting treatment ability.