Abstract
Purpose: Pancreatic ductal adenocarcinoma (PDAC) is generally divided in two subtypes, classical and basal. Recently, single-cell RNA sequencing has uncovered the coexistence of basal and classical cancer cells, as well as intermediary cancer cells, in individual tumors. The latter remains poorly understood; here, we sought to characterize them using a multimodal approach. Experimental Design: We performed subtyping on a single-cell RNA sequencing dataset containing 18 human PDAC samples to identify multiple intermediary subtypes. We generated patient-derived PDAC organoids for functional studies. We compared single-cell profiling of matched blood and tumor samples to measure changes in the local and systemic immune microenvironment. We then leveraged longitudinally patient-matched blood to follow individual patients over the course of chemotherapy. Results: We identified a cluster of KRT17-high intermediary cancer cells that uniquely express high levels of CXCL8 and other cytokines. The proportion of KRT17(high)/CXCL8(+) cells in patient tumors correlated with intratumoral myeloid abundance, and, interestingly, high protumor peripheral blood granulocytes, implicating local and systemic roles. Patient-derived organoids maintained KRT17(high)/CXCL8(+) cells and induced myeloid cell migration in a CXCL8-dependent manner. In our longitudinal studies, plasma CXCL8 decreased following chemotherapy in responsive patients, while CXCL8 persistence portended worse prognosis. Conclusions: Through single-cell analysis of PDAC samples, we identified KRT17(high)/CXCL8(+) cancer cells as an intermediary subtype, marked by a unique cytokine profile and capable of influencing myeloid cells in the tumor microenvironment and systemically. The abundance of this cell population should be considered for patient stratification in precision immunotherapy. See related commentary by Faraoni and McAllister, p. 2297 Conclusions: Through single-cell analysis of PDAC samples, we identified KRT17(high)/CXCL8(+) cancer cells as an intermediary subtype, marked by a unique cytokine profile and capable of influencing myeloid cells in the tumor microenvironment and systemically. The abundance of this cell population should be considered for patient stratification in precision immunotherapy. See related commentary by Faraoni and McAllister, p. 2297