Development of Therapeutic Anti-JAGGED1 Antibodies for Cancer Therapy

Abstract

The role of Notch signaling and its ligand JAGGED1 (JAG1) in tumor biology has been firmly established, making them appealing therapeutic targets for cancer treatment. Here, we report the development and characterization of human/ rat-specific JAG1-neutralizing mAbs. Epitope mapping identified their binding to the Notch receptor interaction site within the JAG1 Delta/Serrate/Lag2 domain, where E228D substitution prevented effective binding to the murine Jag1 ortholog. These antibodies were able to specifically inhibit JAG1-Notch binding in vitro, downregulate Notch signaling in cancer cells, and block the heterotypic JAG1-mediated Notch signaling between endothelial and vascular smooth muscle cells. Functionally, in vitro treatment impaired three-dimensional growth of breast cancer cell spheroids, in association with a reduction in cancer stem cell number. In vivo testing showed variable effects on human xenograft growth when only tumor-expressed JAG1 was targeted (mouse models) but a more robust effect when stromal-expressed Jag1 was also targeted (rat MDA-MB-231 xenograft model). Importantly, treatment of established triple receptor-negative breast cancer brain metastasis in rats showed a significant reduction in neoplastic growth. MRI imaging demonstrated that this was associated with a substantial improvement in blood-brain barrier function and tumor perfusion. Lastly, JAG1-targeting antibody treatment did not cause any detectable toxicity, further supporting its clinical potential for cancer therapy.

Targeting the Notch Signaling Pathway in Chronic Inflammatory Diseases

“…In animal studies, targeting of individual Notch receptors and/or ligands with mAbs exhibit reduced on-target intestinal toxicity compared to that seen following GSI treatment (109,110). For example, use of a murine JAG1-targeting IgG1 mAb in a rat breast cancer xenograft model did not cause toxicity or any effects on body weight (111). Moreover, transient blockade of DLL1 and DLL4 with IgG1 mAbs in the peritransplant period provided durable protection against GVHD after allogeneic bone marrow transplantation without inducing limiting toxicity (109).…”

Development of Dl1.72, a Novel Anti-DLL1 Antibody with Anti-Tumor Efficacy against Estrogen Receptor-Positive Breast Cancer

“…Over the last decade, Abs have become an important component in the arsenal of cancer therapeutics [42]. Antibodies targeting individual Notch receptors and ligands (i.e., JAG1, DLL4) have been developed, showing anti-tumor efficacy against different types of cancers in preclinical studies, with manageable toxicity profiles [41,[43][44][45][46][47][48]. The ER + BC is the most common BC subtype and is treated with anti-estrogenic drugs such as tamoxifen and fulvestrant, presenting a good prognosis.…”

Targeting Notch to Maximize Chemotherapeutic Benefits: Rationale, Advanced Strategies, and Future Perspectives

“…The anti-DLL4 antibody demcizumab in combination with paclitaxel showed some signs of clinical benefit (CBR 42% expressed as PR and SD) and acceptably manageable toxicity in patients with recurrent platinum-resistant ovarian cancer in a phase Ib trial. Interestingly, two cases of PR and two cases of SD were registered in the sub-group of bevacizumab-pretreated patients (n = 5), providing an encouraging possibility of sequential use of the antiangiogenic drugs (NCT01952249) [221].…”

“…Indeed, targeting Jagged1 may circumvent drugassociated toxicity and prevent bone metastasis. Additionally, the effects of anti-Jagged1 on tumor vasculature might provide a promising curative alternative for patients refractory to VEGF inhibitor bevacizumab [221]. DLL4 represents an attractive target for cancer therapy since the blockade of DLL4/Notch signaling has been shown to cause non-productive tumor angiogenesis, to reduce the growth of VEGF-sensitive and resistant tumors, and to affect the CSC pool [221][222][223].…”

“…Additionally, the effects of anti-Jagged1 on tumor vasculature might provide a promising curative alternative for patients refractory to VEGF inhibitor bevacizumab [221]. DLL4 represents an attractive target for cancer therapy since the blockade of DLL4/Notch signaling has been shown to cause non-productive tumor angiogenesis, to reduce the growth of VEGF-sensitive and resistant tumors, and to affect the CSC pool [221][222][223]. However, chronic administration of anti-DLL4 in preclinical studies revealed their potentially significant toxicity due to abnormal activation of endothelial cells, possible induction of vascular neoplasms, and associated damage of multiple organs including liver, thymus, heart, and lung [224].…”