RNA-seq of a mouse primary pancreatic cancer cell line and liver metastasis from mouse model INK4.1syn_Luc
The biology of metastatic pancreatic ductal adenocarcinoma (PDAC) is distinct from that of the primary tumor. We detected an upregulation of the secreted axon guidance molecule Netrin-1 (Ntn1) in human and mouse PDAC metastases that signals through its receptor, uncoordinated- 5b (Unc5b) to facilitate metastasis in vitro and in vivo. The mechanism of Ntn1 induction in liver metastasis is mediated by hepatic stellate cell (HSC) secreted retinoic acid through RXR/RAR and Elf3 signaling. Ntn1 is present in PDAC-derived extracellular vesicles (EVs) and facilitates metastasis by inducing HSC activation through both long and short distance intercellular communication. Importantly, administration of a neutralizing monoclonal NTN1 antibody decreased metastases and increased survival in several murine PDAC models (autochthonous and metastatic). Our studies reveal a new metabolic feed-forward loop for metastatic niche formation in the liver involving NTN1 in PDAC-secreted EVs and retinoic acid released from HSCs which is targetable using anti-NTN1 therapy. Overall design: Ink4.1syn_Luc mice were followed for liver metastasis following orthotopic injection of the Ink4a.1 cell line into the pancreas.  Cell lines of the metastases from 4 different mice were developed in vitro.  After verification that the cell lines did originate from the primary tumor (Ink4a.1 cells), cells were grown to 90% confluency, including the parental Ink4a.1 cell line.  Cell pellets were submitted to Genewiz for RNAseq.  Analysis was completed in house.