You are here
Jagged1 Monclonal Antibody
In Vivo Proof of Principle
- In vivo tumour growth inhibition shown with lead humanised mAbs
- Broad utility in oncology due to role of Jagged1 in multiple cell types
- Patent covers lead mAbs and a novel epitope
The lead anti-Jagged1 monoclonal antibodies (mAbs) come with a strong data package demonstrating high specificity and low nM affinity binding, as well as having been humanised and deimmunised by Lonza. There is clear in vitro inhibitory action against Jagged1 and its downstream targets. Efficacy has been demonstrated in vitro in 3D spheroids to a similar degree as the pan-Notch γ-secretase inhibitors and in vivo in breast cancer and ovarian cancer xenograft models. They bind to a novel Jagged1 epitope that distinguishes them from others in the field.
Cancer Research UK is seeking a co-development partner or a licensee to take the mAbs forward into clinical development.
The clinical relevance of angiogenesis has been firmly established as a rational target for cancer therapy [1,2]. Targeting tumour angiogenesis with anti-VEGF mAbs e.g. with bevacizumab has been a successful strategy . However many patients do not respond, or their response is temporary .
The Notch pathway has been implicated in vascular homeostasis and patterning and in pathological angiogenesis. In addition the Notch pathway is also implicated in cancer where it helps maintain stem cell populations, promotes cell survival, inhibits apoptosis and can drive cell proliferation . However, pan-Notch inhibition with γ-secretase inhibitors exhibited gastrointestinal toxicity; while prolonged treatment with anti-Dll4 mAbs led to the development of vascular/endothelial cell-based tumours. It would appear that Dll1, Dll4 and Jagged2-mediated Notch signalling are required for the homeostasis of intestinal stem cells, whereas deletion of Jagged1 is not .
Jagged1 has also been shown to mediate bone metastasis and support cancer stem cells. By endothelial specific deletion it has also been shown to have a notch-independent role in vascular smooth muscle development. Combined with a role in pericytes, this suggests that Jagged1 has a crucial role in blood vessel maturation. Given that this is thought to be a factor behind the limit of efficacy of anti-VEGF therapy, this suggests a potential combination approach. Thus targeting Jagged1 activated signalling should be an effective mono and/or combination cancer therapy without adverse toxicity effects (a review of Jagged1 as a therapeutic target can be found in ).
The Cancer Research UK Oxford Antibody Therapeutics Programme, led by Prof. Alison Banham, an expert in antibody production and characterisation, in conjunction with experts in Notch pathway biochemistry, Prof. Penny Handford and Prof. Susan Lea, and an academic clinician with expertise in targeting angiogenesis, Prof. Adrian Harris, have developed a series of novel anti-Jagged1 mAbs.
Notch ligands (Jagged1/2, Dll1/4) all have a Delta/Serrate/LAG-2 consensus sequence (DSL) domain, which is involved in their binding to the Notch receptors 1-4. Residues 199-207 of the Jagged1 DSL domain were previously identified by members of the group as being critical for Notch receptor binding .
The group have produced data demonstrating that their lead mAbs, all specifically bind the DSL domain of human-Jagged1, but not Jagged2 or Dll4. They have undertaken epitope mapping to highlight the most important residues, and through competition analysis illustrated that they recognise substantially similar epitopes. What is surprising is that they all recognise E228, which is in fact an aspartic acid (D) residue in mouse Jagged1 (but no other mammals) and therefore the antibodies do not bind mouse Jagged1. The antibodies effectively bind rat Jagged1 and block rat Notch signalling, enabling stromal targeting and toxicity studies to be performed in nude rat models.
They have showed that these mAbs repress endogenous Notch signalling. As shown in Figure 1, there is a dramatic decrease in the relative expression of Notch target gene HES1 in breast cancer MDA-MB-231 3D spheroid growth assays when cultured with the Jagged1 mAbs. Similar effects were also seen in LS174T colorectal cell lines.
In addition the 3D spheroid growth assays showed a strong correlation between Jagged1 expression and decreased spheroid growth after antibody treatment across a panel of breast cancer cell lines. The strongest spheroid growth decrease being seen in the MDA-MB-231 cells (Fig.2).
The mechanism for inhibition of tumour spheroid growth was not via decreased proliferation (%Ki67+ cells), antibody treatment was observed to reduce the frequency of MDAMB-231 cancer stem cells and expression of the protumorigenic cytokine IL6.
In vivo studies carried out in MDA-MB-231 and OVCAR-3 xenograft models with the lead Jagged1 mAbs showed a marked reduction in tumour growth rate. Most recently, rat MDA-MB-231 xenograft studies were used to assess the additional effect of targeting host stromal Jagged1. A greater reduction in tumour growth rate was seen in these rat models (Fig. 3), and more importantly no signs of toxicity compared with the control group. Further rat xenograft experiments are ongoing.
The two lead antibodies 65D and 183D have successfully been humanised and deimmunised by Lonza with no detrimental effect on specificity or affinity.
1. Carmeliet, P et al., Molecular mechanisms and clinical applications of angiogenesis. Nature. 19;473 298-307 (2011) PMID:21593862
2. Li, JL et al., Crosstalk of VEGF and Notch pathways in tumour angiogenesis: therapeutic implications. Front Biosci. 14:3094-110 (2009) PMID:19273260
3. Jain RK et al., Lessons from phase III clinical trials on anti-VEGF therapy for cancer. Nat Clin Pract Oncol. 3(1):24-40 (2006) PMID:16407877
4. Purow, B., Notch inhibition as a promising new approach to cancer therapy. Adv Exp Med Biol. 727:305-19 (2012) PMID:22399357
5. Pellegrinet, L. et al., Dll1- and dll4-mediated notch signaling are required for homeostasis of intestinal stem cells. Gastroenterology. 140(4):1230-1240 (2011) PMID:21238454
6. Li, D., et al. The notch ligand JAGGED1 as a target for anti-tumor therapy. Front Oncol. 4:254. (2014) PMID:25309874
7. Cordle, J et al., A conserved face of the Jagged/Serrate DSL domain is involved in Notch trans-activation and cis-inhibition. Nat Struct Mol Biol. 15(8):849-57 (2008) PMID:18660822