Expression of PD-1 and PDL-1 on macrophages are stimulated by the conditioned media of pancreatic cancer cells and tumor associated macrophages.

Abstract

Programmed cell death-1 (PD-1) and PD-1 ligand 1 (PD-L1) are target molecules for immunotherapy in many cancer types. PD-1/PDL-1 are expressed on many cells including cancer cells however promoted by the impact of several factors in the tumor microenvironment (TME). In this study, we used qPCR to investigate the role of conditioned media (CM) of Pancreatic cancer cells and tumor associated macrophages (TAM) on PD-1/PDL-1 expression on macrophages in vitro. Comparing the relative expression of treated macrophages at three different time points with the control group, both TAM and PDAC conditioned media significantly increased the expression of PD-1. Even though PDL-1 was also increased by both conditioned media at the 24 hrs. time point, however, a decreased expression was noticed particularly by the CM of pancreatic cancer cells. Generally, the study found that secretome of TAM and pancreatic cancer cells are closely related to PD-1/PDL-1 expression by macrophages, suggesting conditioned media a powerful inducer for immune checkpoint inhibition resistance.