Radioimmunotherapy of DU-145 Tumours in Nude Mice: A Pilot Study with E4, A Novel Monoclonal Antibody Against Prostate Cancer

Abstract

The anti-tumour effect of the ¹³¹I-labelled antiprostate monoclonal antibody (MAb) E4 was studied in an experimental model with 41 nude mice, subcutaneously xenografted with a human prostate cancer cell line (DU-145). The mice were divided into four study groups, i.e. one receiving single and another repeated injections of the radiolabelled MAb. A third group was injected with non-labelled MAb, and the fourth served as an untreated control group. The tumour volumes increased similarly in all groups during the 27-day observation period. The tumour tissue was morphologically disintegrated in the group that received repeated radioimmunotherapy (RIT). The tumours from this group contained large fluid-filled cystic parts and demonstrated pronounced cellular and subcellular polymorphism in the remaining viable tumour tissue. The untreated control tumours and single therapy tumours remained solid. The proportion of the total tumour volume that consisted of viable tumour cells, as determined by morphometric techniques, was significantly lower in the ¹³¹I-E4-treated groups. The use of ¹³¹I-labelled E4 MAb has thus demonstrated a promising therapeutic potential.