title: Combination cancer therapy by hapten-targeted prodrug-activating enzymes and cytokines.
abstract: Combination therapy can help overcome limitations in the treatment of heterogeneous tumors. In the current study, we examined whether multiple therapeutic agents could be targeted to anti-dansyl single-chain antibodies (DNS scFv) that were anchored on the plasma membrane of cancer cells. Functional DNS scFv could be stably expressed on CT-26 colon cancer cells both in vitro and in vivo. Dansyl moieties were covalently attached to recombinant beta-glucuronidase (betaG) and interleukin 2 (IL-2) via a flexible poly(ethylene glycol) linker to form DNS-PEG-betaG and DNS-PEG-IL-2 conjugates. The conjugates displayed enzymatic and splenocyte-stimulatory activities, respectively, that were similar to those of the unmodified proteins. The conjugates selectively bound CT-26 cells that expressed anti-DNS scFv (CT-26/DNS cells) but not CT-26 cells that expressed control scFv (CT-26/phOx cells). DNS-PEG-betaG preferentially activated a glucuronide prodrug (BHAMG) of p-hydroxy aniline mustard at CT-26/DNS cells in culture and accumulated in subcutaneous CT-26/DNS tumors after intravenous administration. Systemic administration of DNS-PEG-IL-2 or DNS-PEG-betaG and BHAMG significantly delayed the growth of CT-26/DNS but not control CT-26/phOx tumors. Combination treatment with DNS-PEG-betaG and BHAMG followed by DNS-PEG-IL-2 therapy significantly suppressed the growth of CT-26/DNS tumors as compared to either single-agent regimen. These results show that at least two DNS-modified therapeutic agents can be selectively delivered to DNS scFv receptors in vitro and in vivo, allowing combination therapy of DNS scFv-modified tumors.
authors.affiliation: Faculty of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Kuo-Hsiang
authors.initials: KH
authors.lastname: Chuang
authors.forename: Chiu-Min
authors.initials: CM
authors.lastname: Cheng
authors.forename: Steve R
authors.initials: SR
authors.lastname: Roffler
authors.forename: Yu-Lin
authors.initials: YL
authors.lastname: Lu
authors.forename: Shiu-Ru
authors.initials: SR
authors.lastname: Lin
authors.forename: Jaw-Yuan
authors.initials: JY
authors.lastname: Wang
authors.forename: Wen-Shyong
authors.initials: WS
authors.lastname: Tzou
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Su
authors.forename: Bing-Mae
authors.initials: BM
authors.lastname: Chen
authors.forename: Tian-Lu
authors.initials: TL
authors.lastname: Cheng
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D004359:Drug Therapy, Combination; D005966:Glucuronidase / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D006241:Haptens / Q000276:immunology*; D007376:Interleukin-2 / Q000737:chemistry / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000188:drug therapy* / Q000276:immunology* / Q000473:pathology; D011092:Polyethylene Glycols / Q000737:chemistry; D011355:Prodrugs / Q000378:metabolism* / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000906:Antibodies; D000970:Antineoplastic Agents; D006241:Haptens; D007376:Interleukin-2; D011355:Prodrugs; D011092:Polyethylene Glycols; D005966:Glucuronidase