Erik-Jan Wamsteker

Pancreatic ductal adenocarcinoma (PDAC), the most common subtype of pancreatic cancer, is a deadly disease with a complex tumor microenvironment (TME). Cytotoxic combination chemotherapy treatments are the mainstay of PDAC therapy, but patients rapidly develop chemoresistance, highlighting the need to elucidate how chemotherapy alters the TME and whether these changes drive chemoresistance. In this study, we examined matched pre- and posttreatment tissue specimens using single-cell RNA sequencing (scRNA-seq) and found near-universal enrichment of axonal guidance genes in cancer-associated fibroblasts (CAF) after treatment. These neural CAFs were enriched near sites of perineural invasion (PNI), coinciding with regions of increased tumor cell proliferation, and were enriched in tumor areas distant from nerves after chemotherapy. Metastatic recurrent lesions had the highest prevalence of neural CAFs versus primary tumors and untreated metastases. Neural CAFs showed elevated noncanonical WNT mediators and axonal guidance genes, which complemented matching cognate binding partners in tumor epithelial cells, suggesting a role in tumor–stroma cross-talk. Additionally, in vitro studies revealed enrichment of axonal guidance genes in patient-derived CAF lines upon exposure to chemotherapy or tumor cells. Altogether, these findings implicate fibroblast-derived axonal guidance genes in promoting PDAC invasion and point to a promising therapeutic target for this disease. Significance: Chemotherapy induces changes in the tumor microenvironment and induces fibroblasts with high expression of axonal-guidance genes that may drive tumor progression, uncovering a potential avenue for targeting pancreatic cancer.

Longitudinal Single Cell Sequencing PBMC Differentially Expressed Genes

PDAC Organoids chemoattract myeloid cells in a CXCL8-dependent manner.

Clinical Table of patients whose longitudinally matched plasma samples were subject to CXCL8 chemokine profiling

Clinical table of PDAC patients who underwent longitudinal collection of PBMCS for single cell RNA sequencing

Supplementary epithelial analysis of human PDAC single cell RNA sequencing.

CXCL8-high tumor infiltrating granulocytes are marked by a pro-tumor gene signature.

Clinical Table of University of Michigan patients that were utilized for survival analysis with corresponding CXCL8 and CA19-9 plasma values

Supplementary Table 2 from KRT17high/CXCL8+ Tumor Cells Display Both Classical and Basal Features and Regulate Myeloid Infiltration in the Pancreatic Cancer Microenvironment

CXCL8 levels in patient plasma correlate with abundance of KRT17high; CXCL8+ cancer cells in treatment naïve patients.