Pancreatic ductal adenocarcinoma (PDAC) is an increasingly diagnosed cancer that kills 90% of afflicted patients, with most patients receiving palliative chemotherapy. We identified neuronal pentraxin 1 (NPTX1) as a cancer secreted protein that becomes over-expressed in human and murine PDAC cells during metastatic progression and identified adhesion molecule with Ig like domain 2 (AMIGO2) as its receptor. Molecular, genetic, biochemical and pharmacologic experiments revealed that secreted NPTX1 acts cell-autonomously on the AMIGO2 receptor to drive PDAC metastatic colonization of the liver-the primary site of PDAC metastasis. NPTX1-AMIGO2 signaling enhanced hypoxic growth and was critically required for hypoxia induced factor-1a (HIF1a) nuclear retention and function. NPTX1 is over-expressed in human PDAC tumors and upregulated in liver metastases. Therapeutic targeting of NPTX1 with a high-affinity monoclonal antibody substantially reduced PDAC liver metastatic colonization. We thus identify NPTX1-AMIGO2 as druggable critical upstream regulators of the HIF1a hypoxic response in PDAC.