Abstract PO-097: Addition of losartan to FOLFIRINOX and chemoradiation reduces the expression of pro-invasive and immunosuppressive genes in locally-advanced pancreatic cancer
Authors: Boucher Yves , Posada Jessica M. , Subudhi Sonu , Kumar Ashwin S. , Chen Ivy X. , Ng Mei R. , Mino-Kenudson Mari , Talele Nilesh , Duda Dan G. , Fukumura Dai , Murphy Janet E. , Clark Jeffrey W. , Ryan David P. , Fernandez-Del Castillo Carlos , Hong Theodore S. , Jain Rakesh K. 
Published: November 2021

Purpose: A phase II trial in patients with locally-advanced pancreatic cancer (LAPC) revealed unprecedented rates of complete surgical resection after adding losartan (L) to FOLFIRINOX (FFX) chemotherapy followed by chemoradiation (CRT) (NCT01821729). The aim of this study was to identify potential mechanisms of benefit by assessing the effects of FFX-L+CRT and FFX+CRT on the stromal tumor microenvironment. Experimental Design: We performed a gene analysis of RNA extracted from pancreatic cancer (PC) tissue sections (NanoString nCounter PanCancer Immune Profiling Panel of 730 genes) and immunohistochemistry using surgical samples from patients treated with FFX+CRT (N=15), FFX-L+CRT (N=17) or underwent surgery upfront, without any neoadjuvant therapy (N=9). Results: In comparison to untreated PC, we found 314 and 243 differentially expressed genes (DEGs, adjusted p-value &lt; 0.05) in FFX-L+CRT and FFX+CRT, respectively, and 54 DEGs between FFX-L+CRT and FFX+CRT. PCs from both neoadjuvant FFX-L+CRT and FFX+CRT had increased expression of genes linked to blood vessel maturation (CDH5, THBS1), transvascular migration of leukocytes (JAM3, PECAM1, MCAM, ICAM2), T cell activation (CD6, ALCAM, NFATC1), cytolytic activity of NK cells and T cells (GZMA, GZMB, GZMH, KLRB1) and dendritic cell (DC) related genes (CD209, CD1C, IL3RA). The FOXP3 gene — encoding for a transcription factor that regulates the activity of CD4+ regulatory T cells (Tregs)— was down-regulated in FFX-L+CRT versus untreated samples. Direct comparison of FFX-L+CRT versus FFX+CRT showed increased expression of genes involved in lymphocyte activation (NFATC4, DPP4, STAT5B), and reduced expression of genes that regulate B cell activity (CD22, TRAF3, MS4A1) and CEACAM6, which promotes PC invasion. We also analyzed the correlation of each gene (n=730) with overall survival (OS). For patients treated with FFX-L+CRT, improved OS was negatively correlated with genes that promote invasion in PC (PBK), B cell development and signaling (SYK, BLNK), infiltration of monocytes and macrophages in tumors (CCR2), immune checkpoint (BTLA) and inhibit angiogenesis (TNFSF15). In patients treated with FFX+CRT, OS was positively correlated with genes that stimulate inflammation (IL32), T cell and DC activation (CD48), presentation of glycolipid antigens (CD1E) and antigen processing and presentation by DCs (CD209). Immunohistochemistry studies revealed significantly less residual disease and a higher infiltration of CD8+CD3+ T cells in FFX-L+CRT than FFX+CRT treated tumors. In addition, in patients treated with FFX-L+CRT we found significantly fewer Tregs in PC lesions with a complete/near complete versus poor/no response, confirming our transcriptomic findings. Conclusions: Our findings suggest that FFX-L+CRT can normalize the vasculature, and reduce invasion and the immunosuppressive effects of B cells, CCR2-positive macrophages and Tregs, and thus improve treatment outcome in patients with LAPC, although additional studies are needed.

Citation Format: Yves Boucher, Jessica M. Posada, Sonu Subudhi, Ashwin S. Kumar, Ivy X. Chen, Mei R. Ng, Mari Mino-Kenudson, Nilesh Talele, Dan G. Duda, Dai Fukumura, Janet E. Murphy, Jeffrey W. Clark, David P. Ryan, Carlos Fernandez-Del Castillo, Theodore S. Hong, Rakesh K. Jain. Addition of losartan to FOLFIRINOX and chemoradiation reduces the expression of pro-invasive and immunosuppressive genes in locally-advanced pancreatic cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-097.