Visual Therapy Of Hepatocellular Carcinoma Using A54 Peptide Modified Multifunctional Calcium Phosphate Nano-assembly Drug Delivery System

Hepatocellular carcinoma is a common malignant tumor that threatens human heaLth.There are still many unsolved problems in the treatment of hepatocellular carcinoma in clinic at present.Recent studies indicated that active targeting delivery of antitumor durgs to the tumor tissue is one of the main methods to solve the safe and effective treatment of tumors.In addition,the clinical evaluation of the curative effect of hepatocellular carcinoma was carried out after a treatment cycle,that is always lagging behind in clinical situation,which leads many patients fail to accept the best customized treatment,so it is importment to evaluate the treatment effect of hepatocellular carcinoma in time.In this study,the pH-sensitive and biocompatible materiaL caccium phosphate nanoparticles(CaP)were designed.MR imaging contrast agent gadolinium chelate Gd-DTPA and antitumor drug(Doxorubicin,DOX)were selected as the model drugs.The hepatic cancer cells BEL-7402 specific targeted A54 peptide modified multifunctional calcium phosphate nano-assembly drug delivery system was developed,the antitumor drugs and MR contrast agents were distributed efficiently to the tumor position,the calcium phosphate nanoparticles were hydrolyzed under the acidic condition of the tumor tissue to release the loaded antitumor drugs,the treatment effect was significantly improved,the toxicity and side effects were reduced,and the Gd-DTPA in the co-loading system was used to monitor the effect of tumor treatment by using MR Imaging.And according to the results of treatment effect monitoring,timely adjustment of the treatment plan,so as to realize the safe,efficient and precise individualized treatment of tumors.A multifunctional calcium phosphate nanoparticle(A54-CaP/Gd-DTPA/DOX)was prepared by using the optimized hydrothermal method and the co-loading of Gd-DTPA and DOX by charge adsorption.The prepared A54-CaP/Gd-DTPA/DOX had a small particle size(about 38.10 nm).The A54-CaP/Gd-DTPA/DOX nanoparticles exhibited higher relaxivity(6.02 mM-1s-1)than the clinical common used MR contrast agent Gd-DTPA(3.3765 mM-1s-1).The release studies in vitro indicated that the A54-CaP/Gd-DTPA/DOX showed sustained and pH-dependence release properties of DOX.The human hepatocellular carcinoma cell line BEL-7402 and the normar liver cell L02 were used as the model cells to investigate the cytotoxicity of blank CaP nanoparticles and A54-CaP/Gd-DTPA/DOX.The results showed that the cell viability of the both cell lines was above 90%when the CaP nanoparticles concentration reached 500 ?g/mL.The 50%cellular growth inhibitions(IC50)of A54-CaP/Gd-DTPA/DOX in BEL-7402 cells(IC50=0.45?g/mL)was significantly higher than CaP/Gd-DTPA/DOX(IC50=1.22 ?g/mL,P<0.01),which indicated that A54-CaP/Gd-DTPA/DOX had a good in vitro antitumor activity.In vitro cellular uptake studies,the cell uptake of A54-CaP/Gd-DTPA/DOX on model cells was time-dependence and A54-CaP/Gd-DTPA/DOX showed a strong cell internalization ability for BEL-7402 cells.The female BALB/c nude mice were used as model animals,and the orthotopic hepatocellular carcinoma model of BEL-7402 cells was constructed.The in vivo distribution of free DOX,CaP/Gd-DTPA/DOX and A54-CaP/Gd-DTPA/DOX were investigated subsequently after i.v.administration.The results showed that the tumor fluorescence signal of mice treated with A54-CaP/Gd-DTPA/DOX was obvious after 2 h and maintained more than 48 h.Furthermore,more intense fluorescence signal was observed in the tumor of A54-CaP/Gd-DTPA/DOX group at all the time points.The in vivo pharmacodynamics of free DOX,CaP/Gd-DTPA/DOX and A54-CaP/Gd-DTPA/DOX were investigated in orthotopic BEL-7402 tumor bearing mice and the treatment effects was monitored and evaluated by MR imaging in real time.Compared with free DOX and CaP/Gd-DTPA/DOX,A54-CaP/Gd-DTPA/DOX could inhibit the tumor growth more effectively.The results of histological evaluation studies indicated that the tumor necrosis was more obvious in A54-CaP/Gd-DTPA/DOX group and the A54-CaP/Gd-DTPA/DOX group did not have visible difference compared with the saline group in main organs.In summary,a biosafety and multifunctional calcium phosphate nanoparcticles loaded with MR contrast agents and antitumor drugs simultaneously were designed for T1-weighted MRI guiding targeting hepatocellular carcinoma therapy by using an improved hydrothermal method in this study.Real-time tracking of the therapeutic effect by MR imaging,so that the treatment plan can be adjusted timely to realize the combination of the tumor treatment and effect monitoring,which provides a new concept and a new strategy for the safe and effective treatment of hepatocellular carcinoma.