Bystander killing of tumour cells by antibody-targeted enzymatic activation of a glucuronide prodrug.
RHI-betaG-PEG, formed by linking poly(ethylene glycol)-modified beta-glucuronidase to Mab RH1, was employed to examine bystander killing of antigen-negative N1S1 rat hepatoma cells by activation of a glucuronide prodrug (BHAMG) of p-hydroxyaniline mustard (pHAM) at antigen-positive AS-30D rat hepatoma cells. Sequential treatment of cells with 10 microg ml(-1) RH1-betaG-PEG and 20 microM BHAMG was not toxic to N1S1 cells but killed 99% of AS-30D cells. Over 98% of N1S1 cells, however, were killed in mixed populations containing as few as 2% AS-30D cells after identical treatment, demonstrating an in vitro bystander effect. Subcutaneous injection of AS-30D and N1S1 cells in BALB/c nu/nu mice produced solid tumours containing both cells. Uptake of radiolabelled RH1-betaG-PEG in solid AS-30D and mixed AS-30D/N1S1 tumours was 11.6 and 9.3 times greater than a control antibody conjugate 120 h after i.v. injection. Intravenous treatment with RH1-betaG-PEG and BHAMG cured seven of seven nude mice bearing solid s.c. AS-30D tumours and significantly delayed, compared with control conjugate and prodrug treatment, the growth of mixed N1S1/AS-30D tumours with one cure, showing that targeted activation of BHAMG kills bystander tumour cells in vivo.
Cheng
T L
TL
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
Wei
S L
SL
Chen
B M
BM
Chern
J W
JW
Wu
M F
MF
Liu
P W
PW
Roffler
S R
SR
D000816:Aniline Mustard / Q000031:analogs & derivatives* / Q000378:metabolism / Q000627:therapeutic use; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism / Q000627:therapeutic use; D018906:Antineoplastic Agents, Alkylating / Q000378:metabolism / Q000627:therapeutic use*; D004058:Diffusion; D004354:Drug Screening Assays, Antitumor; D005966:Glucuronidase / Q000378:metabolism / Q000627:therapeutic use*; D007150:Immunohistochemistry; D000922:Immunotoxins / Q000378:metabolism / Q000627:therapeutic use*; D008114:Liver Neoplasms, Experimental / Q000378:metabolism / Q000628:therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D011092:Polyethylene Glycols / Q000378:metabolism / Q000627:therapeutic use*; D011355:Prodrugs / Q000378:metabolism / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D018906:Antineoplastic Agents, Alkylating; D000922:Immunotoxins; D011355:Prodrugs; C000929:hydroxyaniline mustard; D011092:Polyethylene Glycols; D000816:Aniline Mustard; D005966:Glucuronidase