Constructuon Of Reduced Polypeptide Micelle For Co-delivery Of Doxorubicin And TTAIL And The Synergistic Effect Against Drug-resistance In Breast Cancer

The incidence of cancer is rising,has become one of the most important tumor endangering the health of women.Chemotherapy failure was often due to multidrug resistance of breast cancer cells.Therefore,it is a challenging task to study how to increase chemosensitivity of drug-resistant breast cancer cells.In this study,we investigated the vitro and in vivo effects of the combination of broad-spectrum antitumor drug doxorubicin and gene drug pTRAIL with lipoic acid peptide as carrier.In the first part of this thesis,we reported the construction and characterization of a polypeptide loaded with doxorubicin and pTRAIL.The peptide monomers containing poly arginine,histidine and lipoic acid were prepared by the solid phase peptide synthesis,purify by preparative chromatographyby,and analysis by liquid chromatography and mass spectrometry,showed that polypeptide monomers with the experimental requirements.Intramolecular cross-linking of two lipoic acid in the presence of cysteine catalyzed the formation of polypeptide polymers.Identify of polymer synthesis by 1H NMR and gel permeation chromatography.The polypeptide polymer and lipid soluble doxorubicin could self-assembling in peptide micelles under the condition of phacoemulsification,and the external cation rich part combined with gene drugs pTRAIL through electrostatic interaction,preparation of polypeptide micelles carrying doxorubicin and pTRAIL.The peptide micelles were characterized.The results showed that particle size was 69±2.14 nm,potential was 30.7±2.94 mV,drug loading was 12.5%.In the second part of this study,we reported the in vitro evaluation of doxorubicin and pTRAIL loaded lipoic acid peptide micelles against the resistance breast cancer.Compared with pure doxorubicin,lipoic acid modified peptide micelles can be rapidly absorbed by drug-resistant breast cancer cell line MCF-7/ADR,doxorubicin released into the nucleus.Meanwhile,pTRAIL was enriched in cytoplasm.Cytotoxicity experiments showed that lipoic acid peptide can effectively mediate doxorubicin and pTRAIL into cells,synergistic inhibition of drug resistance breast cancer cells,promote cell apoptosis.In the third part of this study,we reported the in vivo effects of doxorubicin and pTRAIL loaded polypeptide micelles against drug resistance breast cancer.The successful construction of MCF-7/ADR model of multidrug resistant breast cancer transplanted subcutaneously in nude mice,through the imaging system for small animal observation of fluorescence labeled polypeptide micelles distribution in nude mice,the results showed that polypeptide micelles can be well enriched in the tumor site,to achieve targeted.Tumor growth inhibition test and mice weight changes and tumor tissue HE staining showed that the polypeptide micellar loading doxorubicin and pTRAIL can inhibit tumor growth,and doxorubicin induced widely cardiotoxicity had no seen in polypeptide micelles group,showed a good security.In this study,we constructed a polypeptide micelle vector containing doxorubicin and gene drug pTRAIL,which provided reference for clinical treatment of drug-resistant breast cancer and other tumors.