GZ17-6.02 is a synthetic formulation of Arum palaestinum extracts that has shown significant antitumor activity against a variety of cancer types including pancreatic ductal adenocarcinoma (PDAC). Previous studies have showed that GZ17-6.02 significantly inhibited PDAC tumor growth in an orthotopic xenograft mouse model for PDAC. Mechanistically, GZ17-6.02 suppressed the expression of multiple tumor stem cell markers in PDAC cells. However, the exact mechanism of action or cellular targets of GZ17-6.02 is not well understood. Considering the substantial effect of GZ17-6.02 on transcription, we hypothesized that GZ17-6.02 might affect the super-enhancers (SEs) networks in pancreatic cancer cells and/or stromal fibroblasts. In this study, we sought to evaluate the effect of GZ17-6.02 on global gene expression, particularly those associated with super-enhancers in PDAC cells and cancer associated fibroblasts (CAFs) using whole genome RNA sequencing (RNA-Seq) and chromatin immunoprecipitation sequencing (ChIP-Seq) assays. Our results showed that GZ17-6.02 induced expression changes in a large number of genes in both pancreatic cancer cells and CAFs. Overall, GZ17-6.02 induced expression changes in more genes in the cancer cells (MIA PaCa-2) than in the CAFs (CAF08). Clustering analysis showed that the top differentially expressed genes are very different between the cancer and CAF cells. In MIA PaCa-2 cells, GZ17-6.02 most significantly affected pathways related to gap junctions whereas in CAF08 cells, pathways related to extracellular matrix proteins such as hyaluronan were among the most significantly dysregulated by the drug. The ChIP-seq results indicated that GZ17-6.02 treatment at 50 μg/mL for 6 hours disrupted many SEs, which may have caused changes in the expression of genes associated with those SEs in the pancreatic cancer cells. The effect of GZ17-6.02 at 50 μg/mL for 6 hours on SEs in the CAF08 was not significant. This is consistent with the fact that relatively small effect on global gene expression in CAF08 cells was observed in the transcriptome analysis. Overall, our study demonstrates that GZ17-6.02 exerts discrete effects on pancreatic cancer cells and CAFs, indicating that the drug may target both the tumors and their associated fibroblasts (stroma). Furthermore, GZ17-6.02 may disrupt super-enhancer networks in the tumor cells to affect genes that play important roles in pancreatic cancer.
Citation Format: Emily Rodela, Pawan Noel, Shaimaa Hussein, Yin C. Lin, Daniel D. Von Hoff, Haiyong Han. Novel antitumor agent GZ17-6.02 exerts discrete effects on transcriptional regulation in pancreatic cancer cells and cancer associated fibroblasts [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr LB-B27.