Open AccessStress‐induced modulation of volume‐regulated anions channels in human alveolar carcinoma cells
Author(s) -
Bach Martin D.,
Sørensen Belinda H.,
Lambert Ian H.
Publication year - 2018
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.13869
Subject(s) - pi3k/akt/mtor pathway , mtorc2 , protein kinase b , mtorc1 , kinase , microbiology and biotechnology , chemistry , taurine , reactive oxygen species , phosphatase , signal transduction , phosphorylation , biochemistry , biology , amino acid
Shift in the cellular homeostasis of the organic osmolyte taurine has been associated with dysregulation of the volume‐regulated anion channel ( VRAC ) complex, which comprises leucine‐rich repeat‐containing family 8 members ( LRRC 8A‐E). Using SDS ‐ PAGE , western blotting, qRT ‐ PCR , and tracer technique ([ 3 H]taurine) we demonstrate that reactive oxygen species ( ROS ) and the cell growth‐associated kinases Akt/ mTOR , play a role in the regulation of VRAC in human alveolar cancer (A549) cells. LRRC 8A is indispensable for VRAC activity and long‐term exposure to hypoosmotic challenges and/or ROS impairs VRAC activity, not through reduction in total LRRC 8A expression or LRRC 8A availability in the plasma membrane, but through oxidation/inactivation of kinases/phosphatases that control VRAC activity once it has been instigated. Pursuing Akt signaling via the serine/threonine kinase mTOR , using mTORC 1 inhibition (rapamycin) and mTORC 2 obstruction (Rictor knockdown), we demonstrate that interference with the PI 3K‐ mTORC 2‐Akt signaling‐axes obstructs stress‐induced taurine release. Furthermore, we show that an increased LRRC 8A expression, following exposure to cisplatin, ROS , phosphatase/lipoxygenase inhibitors, and antagonist of Cys LT 1‐receptors, correlates an increased activation of the proapoptotic transcription factor p53. It is suggested that an increase in LRRC 8A protein expression could be taken as an indicator for cell stress and limitation in VRAC activity.