Decrease of Store-Operated Ca2+ Entry and Increase of Na+/Ca2+ Exchange by Pharmacological JAK2 Inhibition.

Abstract

BACKGROUND/AIMS:

Cell proliferation and migration are regulated by cytosolic Ca2+ activity ([Ca2+]i). Mechanisms modifying [Ca2+]i include store-operated Ca(2+)-entry (SOCE) accomplished by the pore-forming ion channel unit Orai1 and its regulator STIM1, as well as Ca2+ extrusion by Na+/Ca2+ exchanger NCX1. Kinases participating in the orchestration of cell proliferation include the Janus activated kinase JAK2. The present study explored the impact of pharmacological JAK2 inhibition on SOCE and Na+/Ca2+ exchange.

METHODS:

MCF-7 breast carcinoma cells were studied in the absence and presence of the JAK2 inhibitors TG101348 (250 nM - 1 µM) or of AG490 (20 - 40 µM). Transcript levels were quantified with RT-PCR, protein abundance with immunoblotting, [Ca2+]i with Fura-2-fluorescence, SOCE from increase of [Ca2+]i following Ca2+ re-addition after Ca(2+)-store depletion with sarcoendoplasmatic Ca(2+)-ATPase (SERCA) inhibitor thapsigargin (1 µM), and Na+/Ca2+ exchanger activity from increase of [Ca2+]i as well as Ca2+ current in whole cell patch clamp following extracellular Na+ removal. Migratory activity was determined by a wound healing assay.

RESULTS:

JAK2 inhibitor TG101348 (1 µM) decreased Orai1 and STIM1 protein abundance, increased NCX1 transcript levels, decreased Ca2+ release from intracellular stores, decreased SOCE, increased Ca2+ entry as well as Ca(2+)-current following extracellular Na(+)-removal, and decreased migration. Similar effects on Ca2+ release, SOCE, and Ca(2+)-entry following extracellular Na(+)-removal were observed following treatment with AG490.

CONCLUSION:

The present observations disclose a novel powerful mechanism regulating intracellular Ca2+ release, cellular Ca2+ entry, cellular Ca2+ extrusion and cell migration.

• Authors: Jing Yan, Zohreh Hosseinzadeh, Bingbing Zhang, Mirjam Froeschl, Klaus Schulze-Osthoff, Christos Stournaras, Florian Lang
• Journal: Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology (Cell Physiol Biochem) Vol. 38 Issue 2 Pg. 683-95 ( 2016) ISSN: 1421-9778 [Electronic] Germany
• PMID: 26859825 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2016 The Author(s) Published by S. Karger AG, Basel.

Chemical References

• Calcium Channels
• Membrane Proteins
• Neoplasm Proteins
• ORAI1 Protein
• ORAI1 protein, human
• Protein Kinase Inhibitors
• Pyridines
• Pyrrolidines
• STIM1 protein, human
• Sodium-Calcium Exchanger
• Stromal Interaction Molecule 1
• Sulfonamides
• Thiazines
• Tyrphostins
• YM 58875
• alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide
• sodium-calcium exchanger 1
• fedratinib
• Sodium
• JAK2 protein, human
• Janus Kinase 2
• Calcium

Topics

• Calcium (metabolism)
• Calcium Channels (metabolism)
• Cell Movement (drug effects)
• Humans
• Janus Kinase 2 (antagonists & inhibitors, metabolism)
• MCF-7 Cells
• Membrane Proteins (metabolism)
• Neoplasm Proteins (metabolism)
• ORAI1 Protein
• Protein Kinase Inhibitors (pharmacology)
• Pyridines (pharmacology)
• Pyrrolidines (pharmacology)
• Sodium (metabolism)
• Sodium-Calcium Exchanger (metabolism)
• Stromal Interaction Molecule 1
• Sulfonamides (pharmacology)
• Thiazines (pharmacology)
• Tyrphostins (pharmacology)