title: Biodegradable polymer - cisplatin(IV) conjugate as a pro-drug of cisplatin(II).
abstract: A Pt(IV) complex was covalently conjugated to a new biodegradable amphiphilic tri-block copolymer, MPEG-b-PCL-b-PLL, which contains pendant amino groups, to form a polymeric pro-drug of cisplatin(II), MPEG-b-PCL-b-PLL/Pt(IV). The conjugate was assembled into nano-micelles. The Pt(IV) complex, the polymer carrier and the conjugate were characterized systematically. In vitro release experiments showed that drug release from the polymer-Pt(IV) micelles follows an acid responsive and oxidation-reduction sensitive kinetics. HPLC-ICP-MS analysis revealed that cisplatin(II) can be released from the conjugate under an acidic plus a reductive condition which is available inside a cancerous cell. In vitro MTT assay demonstrated that the polymer-Pt(IV) micelles display higher cytotoxicity against SKOV-3 tumor cells than both cisplatin(II) and Pt(IV) complex. This enhanced cytotoxicity is attributed to effective internalization of the micelles by the cells via endocytosis mechanism, which was observed by fluorescence imaging and by direct determination of the platinum uptake by the cells. This polymer-Pt(IV) conjugate is a promising polymeric pro-drug of cisplatin in micellar form. It can protect the Pt(IV) complex against blood clearance. It can enter cancerous cells via endocytosis mechanism and then cisplatin(II) can be released. Therefore, this polymeric pro-drug of cisplatin is expected to find clinical applications in the future.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.
authors.forename: Haihua
authors.initials: H
authors.lastname: Xiao
authors.forename: Ruogu
authors.initials: R
authors.lastname: Qi
authors.forename: Shi
authors.initials: S
authors.lastname: Liu
authors.forename: Xiuli
authors.initials: X
authors.lastname: Hu
authors.forename: Taicheng
authors.initials: T
authors.lastname: Duan
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Zheng
authors.forename: Yubin
authors.initials: Y
authors.lastname: Huang
authors.forename: Xiabin
authors.initials: X
authors.lastname: Jing
mesh_terms: D045744:Cell Line, Tumor; D002945:Cisplatin / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology; D006801:Humans; D009369:Neoplasms / Q000188:drug therapy; D009944:Organoplatinum Compounds / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011355:Prodrugs / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology
chemical_list: D009944:Organoplatinum Compounds; D011355:Prodrugs; D011092:Polyethylene Glycols; C028210:monomethoxypolyethylene glycol; D002945:Cisplatin