Title:Transient Injury-Dependent Up-Regulation of CD105 and its Specific Targeting with an Anti-Vascular Anti-Mouse Endoglin-Nigrin b Immunotoxin
VOLUME: 8 ISSUE: 6
Author(s):Raquel Munoz, Yolanda Arias, Jose Miguel Ferreras, Pilar Jimenez, Maria Angeles Rojo, Carmelo Bernabeu, Damian Cordoba-Diaz and Tomas Girbes
Affiliation:Nutricion y Bromatología, Facultad de Medicina, Universidad de Valladolid, E-47005 Valladolid, Spain.
Keywords:Anti-endoglin Antibody, Anti-tumor Therapy, CD105, CD105 Ablation, Endoglin, Nigrin b
Abstract:Endoglin (CD105), a cell-surface co-receptor for transforming growth factor-beta (TGF-) superfamily members,
is over-expressed in tumor neovasculature and can be targeted with anti-endoglin antibodies, thus becoming an important
tool for anti-tumoral therapy. Injury of the mouse tail induced the transient expression of endoglin, this peaking at
three days after injury and disappearing six days later. An immunotoxin containing the anti-mouse endoglin rat monoclonal
antibody MJ7/18 and the non-toxic ribosome-inactivating protein nigrin b (Ngb) was found to be very active in targeting
mouse endoglin in the L929 fibroblast cell line (IC50 of 4 x 10-11 M). At that concentration, the immunotoxin
lacked unspecific activity. Upon induction of endoglin after injury, the MJ7-Ngb immunotoxin strongly attacked and deranged
the injured tail, inducing tissue damage. Such effects were dependent on the age of the animals and were evident in
six-week-old mice, but not in eight-month-old mice. Our results indicate that endoglin is up-regulated in newly formed
vessels upon injury and can be targeted by the MJ7-Ngb immunotoxin; thus, it could be a useful tool for tumor ablation
research.
