Use of Angiotensin System Inhibitors is Associated with Immune Activation and Longer Survival in Non-Metastatic Pancreatic Ductal Adenocarcinoma

Purpose: Angiotensin system inhibitors (ASIs) can improve prognosis in multiple cancer types, including pancreatic ductal adenocarcinoma (PDAC). However, no study has examined the effect of ASIs alone or combined with adjuvant chemotherapy in resected PDAC patients.<br /><br />Experimental Design: We performed an analysis of the records of ASI users and non-user patients with PDAC seen at Massachusetts General Hospital between January 2006 and December 2010. To identify mechanisms of ASIs in PDAC, we performed RNA-Seq of resected primary lesions. <br /><br />Results: 794 consecutive patients were included. In 299 resected patients, ASI-users experienced longer overall survival (OS) in both univariate (median OS: 36.3 vs. 19.3 months, p=0.011) and adjusted multivariate (HR, 0.505; 95%CI, 0.339 - 0.750; p=0.001) analyses. Propensity score adjusted analysis also showed a longer median OS for chronic ASI-users. In unresected patients, the beneficial effect of ASIs was significant in patients with locally advanced disease, but not in metastatic patients. RNA-Seq analysis revealed in tumors of ASI-users (lisinopril) a normalized extracellular matrix, a reduced expression of genes involved in PDAC progression (e.g. WNT and Notch signaling) and an increased expression of genes linked with the activity of T cells and antigen-presenting cells. Finally, chronic use of ASI was associated with a gene expression signature which is predictive of survival in independent validation cohorts.<br /><br />Conclusions: In patients with non-metastatic PDAC, chronic ASI use is associated with longer OS independently of chemotherapy. Our RNA-Seq analysis suggests that ASI reduce the malignant potential of cancer cells and stimulate the immune microenvironment in primary PDAC.

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