We identified 3 of these enzymes and 2 of them affected IL-8 release in our system: NTPDase2 which is a predominant ATPase and ADK that catalyzes the reversible transphosphorylation reaction leading to ATP and AMP production from two molecules of ADP as substrate. Our initial objective was therefore to characterize the expression of nucleotide metabolizing ectoenzymes. They also express functional receptors that respond to ATP and/or UTP as well as to adenosine that are involved in several functions including cell growth and differentiation, and IL-8 release. Indeed, HT-29 cells express and secrete IL-8 in response to diverse stimuli such as TLR3 agonists. In this work, we used HT-29 colon cancer cell line as a model of intestinal epithelial cells (used in IBD models) as well as a model of cancer cells to investigate if, in such cells, ectoenzymes that modulate nucleotide metabolism can control IL-8 secretion. While ectonucleotidases such as nucleoside triphosphate diphosphohydrolases (NTPDases) generally terminate P2 receptor activation, nucleotide kinases such as adenylate kinase (ADK) may potentiate P2 activation by regenerating the ligand of these receptors from the products of ectonucleotidases. The concentration of P2 receptor agonists is regulated by ectoenzymes that metabolize nucleotides. These substances initiate the host immune responses by activating specific P2 receptors. Extracellular nucleotides (e.g., ATP, ADP, UTP, and UDP) are secreted by host cells in response to injury, such as in conditions of inflammation, and act as danger signals (alarmins) and damage-associated molecular patterns (DAMPs). We have previously observed that IL-8 secretion, and even function, can be controlled by nucleotide receptors. Therefore, a better understanding of the mechanisms that drive or mediate IL-8 release is imperative. Altogether, this suggests that inhibition of IL-8 production could be a potential treatment for both chronic inflammatory diseases and cancer. Elevated IL-8 signaling has also been observed within the tumor microenvironment of numerous cancers where it enhances tumor progression via the activation of pathways that promote proliferation, angiogenesis, migration, invasion, and cell survival. Accordingly, IL-8 has been implicated in a number of inflammatory diseases such as IBD. Interleukin-8 (IL-8) or CXCL8 is a proinflammatory chemokine originally identified as a neutrophil chemoattractant, which is an important contributor to the induction of innate immunity. In addition, the long-term use of anti-inflammatory drugs such as aspirin decreases the risk of several cancer types. For instance, IBD is associated with an increased risk of colon cancer development. Indeed, a number of chronic inflammatory conditions increase the risk of developing cancers. Inflammation is a major contributor to the development and progression of many human cancers and is obviously a key constituent of inflammatory diseases such as inflammatory bowel diseases (IBD). Taken together, these results demonstrate the presence of 3 ectoenzymes at the surface of HT-29 cells that control nucleotide levels and adenosine production (NTPDase2, ecto-5вЂІ-nucleotidase and adenylate kinase) and that P2 receptor-mediated signaling controls IL-8 release in HT-29 cells which is modulated by the presence of NTPDase2 and adenylate kinase. In response to poly (I:C), with or without ATP and/or ADP, HT-29 cells released IL-8 and this secretion was modulated by the presence of NTPDase2 and adenylate kinase. The expression of the ectoenzymes was evaluated by RT-PCR, qPCR, and immunoblotting, and their activity was analyzed by RP-HPLC of the products and by detection of produced from the hydrolysis of ATP, ADP, and AMP. We first identified that HT-29 cells regulated adenosine and adenine nucleotide concentration at their surface by the expression of the ectoenzymes NTPDase2, ecto-5вЂІ-nucleotidase, and adenylate kinase. Here we investigated whether IL-8 release by intestinal epithelial HT-29 cells, a cancer cell line, is modulated by extracellular nucleotide metabolism.

We previously observed that IL-8 secretion and function can be modulated by nucleotide (P2) receptors.

Interleukin-8 (IL-8) plays key roles in both chronic inflammatory diseases and tumor modulation.

Ecto proctologist