title: A CD13-targeting peptide integrated protein inhibits human liver cancer growth by killing cancer stem cells and suppressing angiogenesis.
abstract: CD13 is a marker of angiogenic endothelial cells, and recently it is proved to be a biomarker of human liver cancer stem cells (CSCs). Herein, the therapeutic effects of NGR-LDP-AE, a fusion protein composed of CD13-targeting peptide NGR and antitumor antibiotic lidamycin, on human liver cancer and its mechanism were studied. Western blot and immunofluorescence assay demonstrated that CD13 (WM15 epitope) was expressed in both human liver cancer cell lines and vascular endothelial cells, while absent in normal liver cells. MTT assay showed that NGR-LDP-AE displayed potent cytotoxicity to cultured tumor cell lines with IC50values at low nanomolar level. NGR-LDP-AE inhibited tumorsphere formation of liver cancer cells, and the IC50values were much lower than that in MTT assay, indicating selectively killing of CSCs. In endothelial tube formation assay, NGR-LDP-AE at low cytotoxic dose significantly inhibited the formation of intact tube networks. Animal experiment demonstrated that NGR-LDP-AE inhibited the growth of human liver cancer xenograft. Immunohistochemical analysis showed that NGR-LDP-AE induced the down-regulation of CD13. In vitro experiment using cultured tumor cells also confirmed this result. NGR-LDP-AE activated both apoptotic and autophagic pathways in cultured tumor cells, while the induced autophagy protected cells from death. Conclusively, NGR-LDP-AE exerts its antitumor activity via killing liver CSCs and inhibiting angiogenesis. With one targeting motif, NGR-LDP-AE acts on both liver CSCs and angiogenic endothelial cells. It is a promising dual targeting fusion protein for liver cancer therapy, especially for advanced or relapsed cancers.
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Tiantan Xili, Beijing, China.
authors.forename: Yan-Bo
authors.initials: YB
authors.lastname: Zheng
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Tiantan Xili, Beijing, China.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Gong
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Tiantan Xili, Beijing, China.
authors.forename: Xiu-Jun
authors.initials: XJ
authors.lastname: Liu
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Tiantan Xili, Beijing, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Tiantan Xili, Beijing, China.
authors.forename: Yong-Su
authors.initials: YS
authors.lastname: Zhen
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001343:Autophagy / Q000187:drug effects; D018826:CD13 Antigens / Q000378:metabolism*; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D008099:Liver / Q000098:blood supply / Q000187:drug effects / Q000473:pathology; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000473:pathology; D008819:Mice, Nude; D058990:Molecular Targeted Therapy / Q000379:methods; D014411:Neoplastic Stem Cells / Q000187:drug effects*; D009389:Neovascularization, Pathologic / Q000188:drug therapy*; D009842:Oligopeptides; D011994:Recombinant Proteins / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; C526428:NGR peptide; D009842:Oligopeptides; D011994:Recombinant Proteins; D018826:CD13 Antigens
keywords: CD13; NGR-LDP-AE; angiogenesis; cancer stem cells; liver cancer