A monoclonal antibody-β-glucuronidase conjugate as activator of the prodrug epirubicin-glucuronide for specific treatment of cancer

Abstract

Summary The anti-pan carcinoma monoclonal antibody (MAb) 323/A3, linked to E. coli-derived pglucuronidase (GUS) was used to study the tumour-site-selective activation of the prodrug Epirubicinglucuronide (Epi-glu). Epi-glu was isolated from the urine of patients treated with Epirubicin (Epi) by reversed phase chromatography on a silica-C18 column. Epi-glu was stable in human blood and was not converted into Epi by A2780, MCF-7, or

A novel doxorubicin-glucuronide prodrug DOX-GA3 for tumour-selective chemotherapy: distribution and efficacy in experimental human ovarian cancer

“…In ADEPT, prodrugs are activated in tumours by an administered tumour-specific monoclonal antibody-enzyme conjugate. We have shown earlier that a conjugate of monoclonal antibody 323/A3 and human β-glucuronidase bound to tumour cells can activate anthracycline prodrugs in an efficient manner (Haisma et al, 1992). In addition to the chemically prepared conjugate a single chain Fv fusion protein may be used .…”

“…The enzyme can only be detected in very low concentrations in the circulation (Fishman, 1970). Therefore, β-glucuronidase may be exploited for the specific activation of glucuronide prodrugs in tumour tissue.We have developed glucuronide derivatives of anthracyclines and showed that these prodrugs, such as epirubicin-glucuronide (Haisma et al, 1992) and daunorubicin-glucuronides (Leenders et al, 1995;Houba et al, 1996), are relatively non-toxic in vitro and can be activated by β-glucuronidase to yield the active anthracycline. Treatment with the glucuronide prodrug daunorubicin-GA3 (DNR-GA3) induced a better tumour growth delay than daunorubicin (DNR) when studied at equitoxic doses in 3 human ovarian cancer xenografts which were sensitive to DNR (Houba et al, 1998).…”

Cell surface display of a lysosomal enzyme for extracellular gene-directed enzyme prodrug therapy

“…(7) Extracellular ␤-glucuronidase is found at high levels in necrotic tumor areas 18,21 which will potentiate the efficacy of TM-␤Gluc-based GDEPT approaches. (8) Other ␤-glucuronide products have been described, 19,[22][23][24][25][26][27][28][29] suggesting that the same enzyme can potentially be used with a plethora of other chemotherapeutics. This also opens up the possibility of combining different prodrugs similar to conventional chemotherapy.…”

“…25 Two days later cells were lysed with 250 l 0.5% sodium-deoxycholate in PBS. Aliquots were used for determination of enzymatic activity and immunoblotting.…”

Gene expression imaging by enzymatic catalysis of a fluorescent probe via membrane-anchored β-glucuronidase

“…We hypothesized that specificity could be retained with this endogenous enzyme because bG is located in lysosomes 15 and only very low levels of bG are found in human serum. 16 Glucuronides are charged at physiological pH values which hinders their diffusion across the lipid bilayer of cells, 17,18 effectively sequestering the glucuronide probe from contact with lysosomal bG. Conjugation of glucuronide moieties to xenobiotics by UDP-glucuronosyl transferases is also a major detoxification pathway in rodents and humans, 19 suggesting that a glucuronide probe should be resistant to premature activation by endogenous bG under physiological conditions.…”