TWEAK, a TNF family
ligand with pleiotropic cellular functions, was originally described as capable of inducing
tumor cell death in vitro. TWEAK functions by binding its
receptor, Fn14, which is up-regulated on many human solid
tumors. Herein, we show that intratumoral administration of TWEAK, delivered either by an adenoviral vector or in an
immunoglobulin Fc-fusion form, results in significant inhibition of
tumor growth in a breast xenograft model. To exploit the TWEAK-Fn14 pathway as a therapeutic target in oncology, we developed an anti-Fn14 agonistic antibody,
BIIB036. Studies described herein show that
BIIB036 binds specifically to Fn14 but not other members of the
TNF receptor family, induces Fn14 signaling, and promotes
tumor cell apoptosis in vitro. In vivo,
BIIB036 effectively inhibits growth of
tumors in multiple xenograft models, including colon (WiDr), breast (MDA-MB-231), and gastric (NCI-N87)
tumors, regardless of
tumor cell growth inhibition response observed to
BIIB036 in vitro. The anti-
tumor activity in these cell lines is not TNF-dependent. Increasing the
antigen-binding valency of BIB036 significantly enhances its anti-
tumor effect, suggesting the contribution of higher order cross-linking of the
Fn14 receptor. Full Fc effector function is required for maximal activity of
BIIB036 in vivo, likely due to the cross-linking effect and/or ADCC mediated
tumor killing activity. Taken together, the anti-
tumor properties of
BIIB036 validate Fn14 as a promising target in oncology and demonstrate its potential therapeutic utility in multiple solid
tumor indications.