Abstract 1904: Versican production is driven by both epithelial and stromal cells in pancreatic cancer

Abstract

Background: Pancreatic ductal adenocarcinoma (PDAC) recently became the third-deadliest cancer due to resistance to chemotherapy and immunotherapies. The tumor microenvironment (TME) in PDAC is thought to contribute to this resistance, with up to 80% of the tumor bulk consisting of stroma. We investigated the role of two major stromal cell types, pancreatic stellate cells (PSCs) and macrophages, in the production of the immunosuppressive proteoglycan versican (VCAN) as a precursor to the identification of novel mechanisms that may enhance therapeutic response. Methods: B6 KPC mice were utilized as a murine model of PDAC. A human PDAC tissue microarray (TMA) was developed representing normal and neoplastic pancreatic tissue across 131 patients. Immunohistochemistry (IHC) was used to determine levels of VCAN and CD8+ T cells. Bone marrow-derived macrophages (BMDMs) were differentiated from BALB/c mouse femurs and polarized to M1 (antitumor) or M2 (protumor) status. Additionally, PDAC organotypic spheroids were derived from both human and murine tissues whereas PSCs were derived solely from human tissue. Results: IHC analysis of KPC tumors revealed elevated levels of stromal VCAN compared to normal pancreatic tissue (p<0.001, n=20). VCAN accumulation was increased even in the earliest stages of acinar-to-ductal metaplasia in KPC mice. Areas of intense stromal VCAN staining trended toward reduced CD8+ T cell infiltration (4.9 vs 7.3 cells/high power field (hpf), p=0.3). IHC analysis of human PDAC revealed elevated VCAN accumulation across all stages compared to the normal adjacent tissue (n=231, p<0.001). Areas of high VCAN accumulation demonstrated reduced CD8+ T cells compared to areas of low VCAN (0.6 vs 2.9 cells/hpf, p<0.001). To investigate cell types responsible for enhanced VCAN accumulation in the tumor microenvironment, relative expression (RE) of VCAN was compared in vitro to M0 macrophages. Organotypic cancer spheroids demonstrated increased expression of VCAN from KPC mice (RE=49, n=2) and patient-derived PDAC tissue (RE=14, p=0.01, n=3). M1-polarized BMDMs had increased expression of VCAN (RE=24) compared to M2 BMDMs (RE=8) (p<0.001, n=3). Interestingly, M1 BMDMs cultured in PDAC-conditioned media had reduced RE of M1 markers: TNFα (395 vs 37, p=0.03) and iNOS (24723 vs 4813, p=0.003), and increased M2 markers: Arg-1 (127 versus 1049, p=0.02) and YM-1 (0.5 vs 3, p=0.02). PDAC-conditioned media also reduced VCAN expression of M1 BMDMs (24 vs 9, p=0.02). PSCs derived from human PDAC also demonstrated enhanced RE of VCAN compared to negative controls (RE=68, p=0.017) with no significant change in the presence of PDAC conditioned media (p=0.4). Conclusions: The accumulation of VCAN is common in PDAC and correlates with CD8+ T cell exclusion. Epithelial and stromal components are responsible for VCAN production. VCAN deserves further investigation as a target for therapeutic interventions for PDAC. Citation Format: Hanna R. Rainiero, Philip B. Emmerich, Chelsie K. Sievers, Connor J. Maloney, Rosabella T. Pitera, Susan N. Payne, Mitchell G. Depke, Cheri A. Pasch, Linda Clipson, Jillian K. Johnson, Kristina A. Matkowskyj, Fotis Asimakopoulos, Dustin A. Deming. Versican production is driven by both epithelial and stromal cells in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1904.

Distance-depending transcriptome changes of pancreatic stellate cells in paracrine pancreatic ductal adenocarcinoma co-culture models

“…The elevated levels of VCAN in this work are consistent with previous work from Rainiero et al, where even in the earliest stages of PDA, VCAN production was detected by immunohistochemistry in epithelial and stromal cells. Elevated levels of VCAN could also be detected in PSC derived from human PDA, but interestingly, PDA-conditioned media did not signi cantly in uence the expression in PSC [35]. This emphasizes the potential requirement for cellular crosstalk, rather than solely secreted factors from cancer cells, in speci c processes such as VCAN upregulation.…”

VCAN Hypomethylation and Expression as Predictive Biomarkers of Drug Sensitivity in Upper Urinary Tract Urothelial Carcinoma

“…Monocytes/macrophages and stromal fibroblasts are capable of secreting VCAN, which is involved in the formation of the HA matrix. Additionally, VCAN is considered as a cancer-causing factor in various types of cancer, including pancreatic cancer, myeloma, ovarian cancer, hepatocellular carcinoma, colon carcinoma, glioma and bladder cancer [ 22 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. The role of VCAN in UTUC has not been reported previously, but our results suggest that VCAN expression has a significant relationship with the pathological features and patient survival in UTUC.…”