Canine mammary cancer cells direct macrophages toward an intermediate activation state between M1/M2

Abstract

BackgroundCanine mammary carcinoma is the most common cancer in female dogs and is often fatal due to the development of distance metastasis. The microenvironment of a tumour often contains abundant infiltrates of macrophages called tumour-associated macrophages (TAMs). TAMs express an activated phenotype, termed M2, which sustains proliferation of cancer cells, and has been correlated with poor clinical outcomes in human cancer patients. Cancer cells themselves have been implicated in stimulating the conversion of macrophages to a TAM with an M2 phenotype. This process has yet to be fully elucidated. Here we investigate the interplay between cancer cells and macrophages in the context of canine mammary carcinoma.ResultsWe show that cancer cells inhibit lipopolysaccharide (LPS)-induced macrophage activation. Further, we show that macrophage associated proteins, colony-stimulating factor (CSF)-1 and C-C motif ligand (CCL)-2, stimulate macrophages and are responsible for the effects of cancer cells on macrophages. We suggest the existence of a feedback loop between macrophages and cancer cells; while cancer cells influence the phenotype of the TAMs through CSF-1 and CCL2, the macrophages induce canine mammary cancer cells to upregulate their own expression of the receptors for CSF-1 and CCL2 and increase the cancer cellular metabolic activity. However, these cytokines in isolation induce a phenotypic state in macrophages that is between M1 and M2 phenotypes.ConclusionsOverall, our results demonstrate the extent to which canine mammary carcinoma cells influence the macrophage phenotype and the relevance of a feedback loop between these cells, involving CSF-1 and CCL2 as important mediators.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-015-0473-y) contains supplementary material, which is available to authorized users.

A Comparative Approach of Tumor-Associated Inflammation in Mammary Cancer between Humans and Dogs

“…TAMs in canine mammary cancer have already been associated, by our group, with skin ulceration, histological type, nuclear grade, tubular differentiation, and decrease in overall survival [56]. Similarly to human breast cancer, in canine mammary cancer the macrophages also polarize toward the M2 phenotype [57]. Recently, we and others demonstrated that TAM infiltration is significantly associated with VEGF expression in malignant canine mammary tumors and that genes involved in angiogenic cellular pathways have been significantly upregulated in macrophages cocultured with canine mammary tumor cell lines [20, 58].…”

“…Evidences from clinical and experimental studies indicate that macrophages are versatile cells that are capable of displaying different functional activities in order to promote breast cancer progression and metastasis [20, 120, 121]. TAMs polarization in mammary tumor sites are modulated by the tumor microenvironment and these cells are “educated” adopting a role that facilitates angiogenesis, matrix breakdown, and tumor cell motility in a COX-2-dependent manner [71, 105].…”

Nuclear M-CSF Accelerates DNA Replication and Cell Proliferation in HeLa Human Cervical Cancer Cells

“…The cell concentration was adjusted for 5×10 4 cells/mL to vaccinate 96-well plates, each well 180 µL. With RPMI1640 medium dissoluted, (1, 3, 5, 7, 9 nmol/L) antisense oligonucleotides were joined every well for 44 h, and 20 µL MTT (5 mg/mL) was added to cultivate for 4 h, then 200 uL DMSO was added.…”

“…The three kinds of HeLa cells (1x10 4 per well) were cultured in 96-well plates. Thereafter, 20 µL MTT solution was added to each well.…”

“…It has been shown that HPV enhanced expression of IL-1β and IL-8, while G-CSF and M-CSF did not change. M-CSF, also called colony-stimulating factor-1 (CSF-1), is important in controlling the survival, proliferation and differentiation of the monocyte/macrophage lineage cells both in vivo and in vitro [4]. As an extracellular signaling molecule, M-CSF swims in body fluids in normal physiological conditions.…”