caa a22 4500 469074442 CHVBK 20180323132931.0 cr unu---uuuuu 170328e19920901xx s 000 0 eng 10.1007/BF01741556 doi (NATIONALLICENCE)springer-10.1007/BF01741556 Analysis of a conjugate between anti-carcinoembryonic antigen monoclonal antibody and alkaline phosphatase for specific activation of the prodrug etoposide phosphate [Elektronische Daten] [Hidde Haisma, Epie Boven, Monique van Muijen, Robert De Vries, Herbert Pinedo] Summary: The selective targeting of tumours by enzymes conjugated to monoclonal antibodies (mAb) may be an ideal approach to convert relatively nontoxic prodrugs into active agents at the tumour site. We used the anti-carcinoembryonic antigen mAb BW431/26 conjugated to alkaline phosphatase (AP) and phosphorylated etoposide (etoposide-P) as a prodrug to study the feasibility of this concept. Etoposide was phosphorylated with POCl3. Quantitative hydrolysis of etoposide-P to etoposide occurred within 10 min in the presence of AP. BW431/26 and AP were conjugated using a thioether bond. The AP conjugate retained 93% of its calculated activity.125I-labelled AP conjugate did not show a reduction of immunoreactivity as determined by a cell-binding assay. SW1398 colon cancer cells were used to analyse the cytotoxicity of etoposide and etoposide-P. Etoposide (IC50 22 µM) was 100 times more toxic than etoposide-P (20% growth inhibition at 200 µM). Pretreatment of the cells with BW431/26-AP prior to etoposide-P exposure resulted in a dramatic increase in cytotoxicity (IC50 70 µM). The pharmacokinetics and tumour-localizing properties of BW431/27 and the AP conjugate were assessed in nude mice bearing SW1398 tumours. BW431/26 showed excellent tumour localization (10% of the injected dose/g tissue retained from 8 h to 120 h), whereas the AP conjugate showed a reduced tumour uptake (3%-0.3% of the injected dose/g tissue at 8-120 h), a faster clearance from the circulation and a high liver uptake. Radiolabelled AP showed a similar pharmacokinetic profile to the AP conjugate. Gel filtration analysis of blood, liver, and tumour samples indicated good stability of the conjugate. Springer-Verlag, 1992 Monoclonal antibody nationallicence Alkaline phosphatase nationallicence Prodrug activation nationallicence Etoposide nationallicence Haisma Hidde Department of Oncology, Free University Hospital, P. O. Box 7057, 1007 MB, Amsterdam, The Netherlands aut Boven Epie Department of Oncology, Free University Hospital, P. O. Box 7057, 1007 MB, Amsterdam, The Netherlands aut van Muijen Monique Department of Oncology, Free University Hospital, P. O. Box 7057, 1007 MB, Amsterdam, The Netherlands aut De Vries Robert Department of Oncology, Free University Hospital, P. O. Box 7057, 1007 MB, Amsterdam, The Netherlands aut Pinedo Herbert Department of Oncology, Free University Hospital, P. O. Box 7057, 1007 MB, Amsterdam, The Netherlands aut Cancer Immunology, Immunotherapy Springer-Verlag 34/5(1992-09-01), 343-348 0340-7004 34:5<343 1992 34 262 https://doi.org/10.1007/BF01741556 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01741556 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Haisma Hidde Department of Oncology, Free University Hospital, P. O. Box 7057, 1007 MB, Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- Boven Epie Department of Oncology, Free University Hospital, P. O. Box 7057, 1007 MB, Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- van Muijen Monique Department of Oncology, Free University Hospital, P. O. Box 7057, 1007 MB, Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- De Vries Robert Department of Oncology, Free University Hospital, P. O. Box 7057, 1007 MB, Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- Pinedo Herbert Department of Oncology, Free University Hospital, P. O. Box 7057, 1007 MB, Amsterdam, The Netherlands aut NATIONALLICENCE 773 0- Cancer Immunology, Immunotherapy Springer-Verlag 34/5(1992-09-01), 343-348 0340-7004 34:5<343 1992 34 262 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer