A translational study of monocyte receptor expression and chemotaxis between dogs and humans with and without osteosarcoma (TUM6P.975)

Abstract

Abstract Spontaneous canine osteosarcoma (OSA) is an excellent translational model for human OSA. Published reports of both canine and human OSA indicate that monocyte activation is important for controlling primary and metastatic disease. The purpose of this study was to identify phenotypic and chemotactic differences between monocytes from dogs with OSA, healthy dogs and to determine if the same findings occur in human OSA. Canine peripheral blood mononuclear cells (PBMCs) were incubated with antibodies against CD14, CD32, CD62L, CD16, CD11c, CCR2, CCR7, CD43, CX3CR1, and CXCR2 and analyzed by flow cytometry. In OSA dogs (n=18), CD16 surface expression was increased, and CD62L, CCR2, CCR7, CD43, CX3CR1 and CXCR2 expression was decreased, compared to controls (n=13, p<0.01, MWU). Additionally, decreased chemokine receptor expression was associated with increased peripheral blood monocyte counts. Preliminary data from human OSA patients suggests the monocyte receptor expression profile is similar to that in canine OSA. Based upon these results, we hypothesize that monocytes exhibit altered chemotaxis in OSA patients. Assessment of in vitro monocyte chemotaxis in healthy patients compared with OSA patients, in both dogs and humans, is currently underway.