50: Anti-Netrin-1 Therapy Inhibits Metastasis and Improves Survival in Pancreatic Cancer

The majority of patients undergoing surgery for early-stage pancreatic cancer (PC) die from disseminated micrometastatic disease. Therapies to inhibit progression from micrometastatic to clinically detectable disease is an unmet need.  The biology of PC metastasis is distinct from the primary tumor and largely driven by epigenetic changes that upregulate embryonic pathways. One such pathway is the Netrin-1/Unc5b axon guidance pathway. We identified Netrin-1 as an upregulated gene during progression from primary to metastatic PC, elucidated the mechanism, and demonstrate interfering with Netrin-1 (NTN1) leads to PDAC cell death. 



Methods:

NTN1 expression was investigated in human and murine tissue specimens from early and advanced PDAC and through analysis of the TCGA database. CRISPR modification of murine cell lines was utilized to study the effect of NTN1 and its receptors on cellular invasiveness, migration, and survival both in-vivo and in vitro models. A novel inhibitor of NTN1 (NP137, Netris Pharma) was tested in several preclinical PC models .



Results:

NTN1 expression is increased in metastatic murine and human PC compared to the primary tumor. It is also upregulated the quasi-mesenchymal subtype.  Murine and TCGA data indicate that Unc5b is the dominant receptor and knock-down (KD) or knock-out (KO) of either NTN1 or Unc5b decreases migration, invasion, and cell survival in vitro and reduces hepatic metastatic growth in vivo. Hepatic stellate cell (HSC) secreted retinoic acid upregulates NTN1 through an RXR/RAR and Elf mediated mechanism. Recombinant NTN1 added to HSCs induced their activation. Tumors generated from NTN1 wild type (WT) increased HSC activation compared to KO cell lines. We detected NTN1 within extracellular vesicles (EV). Mice preconditioned with EVs from NTN1-KO cells demonstrated decreased metastases compared to mice preconditioned with WT EV’s.  Treatment of several murine PDAC models with a monoclonal antibody to NTN1 decreased metastases and improved survival.



Conclusions: These studies to show that Netrin-1 is driver of metastatic PC and that its upregulation can be exploited as a therapeutic vulnerability.  The elucidation of the mechanism of upregulation through HSC secreted retinoic acid and the identification of NTN1 in EV’s represent two major contributions to the NTN1 field.  These studies reveal a novel strategy to inhibit metastatic progression of pancreatic cancer and provide the basis for the investigation of FOLFIRINOX +/- NP137 in a randomized Phase II SWOG trial for resectable/borderline resectable PC in 2024.