Adenosine arrests breast cancer cell motility by A3 receptor stimulation

Abstract

In neutrophils, adenosine triphosphate (ATP) release and autocrine purinergic signaling regulate coordinated cell motility during chemotaxis. Here, we studied whether similar mechanisms regulate the motility of breast cancer cells. While neutrophils and benign human mammary epithelial cells (HMEC) form a single leading edge, MDA-MB-231 breast cancer cells possess multiple leading edges enriched with A3 adenosine receptors. Compared to HMEC, MDA-MB-231 cells overexpress the ectonucleotidases ENPP1 and CD73, which convert extracellular ATP released by the cells to adenosine that stimulates A3 receptors and promotes cell migration with frequent directional changes. However, exogenous adenosine added to breast cancer cells or the A3 receptor agonist IB-MECA dose-dependently arrested cell motility by simultaneous stimulation of multiple leading edges, doubling cell surface areas and significantly reducing migration velocity by up to 75 %. We conclude that MDA-MB-231 cells, HMEC, and neutrophils differ in the purinergic signaling mechanisms that regulate their motility patterns and that the subcellular distribution of A3 adenosine receptors in MDA-MB-231 breast cancer cells contributes to dysfunctional cell motility. These findings imply that purinergic signaling mechanisms may be potential therapeutic targets to interfere with the motility of breast cancer cells in order to reduce the spread of cancer cells and the risk of metastasis.

A3 Adenosine Receptors as Modulators of Inflammation: From Medicinal Chemistry to Therapy

“…Specifically, A 3 AR is translocated to the neutrophil leading edge, and adenosine generated by ecto-ATPases/nucleotidases results in autocrine stimulation of A 3 AR-enhanced polarized migration, following its initiation by ATP activating the P2Y 2 receptor. 34,[261][262][263] This was confirmed also in a sepsis model of A 3 AR knockout (KO) mice where a reduction in the recruitment of neutrophils to the lung and peritoneum was observed. 264 In contrast, in human breast cancer cells, the A 3 AR is expressed in multiple leading edges where it promotes cell migration with numerous directional changes.…”

“…In recent years, it has been reported that the A 3 AR is distributed in a highly polarized fashion on the neutrophils cell membrane and contribute to their chemotaxis and migration. Specifically, A 3 AR is translocated to the neutrophil leading edge, and adenosine generated by ecto‐ATPases/nucleotidases results in autocrine stimulation of A 3 AR‐enhanced polarized migration, following its initiation by ATP activating the P2Y 2 receptor . This was confirmed also in a sepsis model of A 3 AR knockout (KO) mice where a reduction in the recruitment of neutrophils to the lung and peritoneum was observed .…”

“…In contrast, in human breast cancer cells, the A 3 AR is expressed in multiple leading edges where it promotes cell migration with numerous directional changes. Indeed, exogenous adenosine may simultaneously stimulate A 3 AR on all leading edges of the cell, inducing it to spread out in opposing directions resulting in arrest of cell motility . Furthermore, it has been found that the endogenous A 3 AR aggregates into plaque‐like microdomains that affect cytoskeletal remodeling.…”

Pathological overproduction: the bad side of adenosine

“…The adenosine machinery also mediates its effects directly in tumour cells by affecting their proliferation and cell death through recruitment of different receptors. In particular, opposite effects on cell growth and motility have been observed, with A 1 , A 2A and A 2B receptors being promoters whilst A 3 receptors are inhibitors of cell proliferation (Merighi et al , ; ; Gessi et al , ; Antonioli et al , ; Borea et al , ; Ledderose et al , ). Indeed, it is important to note that clinical trials are undergoing for A 3 receptor agonists, based on their antiproliferative effects, representing an opportunity for new anticancer drugs (Borea et al , ).…”

Polarized Entamoeba: A model for stable bleb driven motility

“…Dominant positive expression of URE3-BP in Eh induced an elongated morphology which was reported to be highly invasive (Gilchrist et al, 2010), and so the polarized form may have an important role in the pathogenesis. The role of adenosine receptors on cell motility indicted the possibility of purinergic signaling (Chen et al, 2006;Ledderose et al, 2016) in controlling motility and chemotaxis of Entamoeba. Animal cells contain 5-10 mM of ATP in their cytosol, and the tissue damage by Entamoeba may cause leakage of ATP from damaged cells.…”