Activation of RyR2 by class I kinase inhibitors

Abstract

Background and Purpose Kinase inhibitors are a common treatment for cancer. Class I kinase inhibitors that target the ATP‐binding pocket are particularly prevalent. Many of these compounds are cardiotoxic and can cause arrhythmias. Spontaneous release of Ca2+ via cardiac ryanodine receptors (RyR2), through a process termed store overload‐induced Ca2+ release (SOICR), is a common mechanism underlying arrhythmia. We explored whether class I kinase inhibitors could modify the activity of RyR2 and trigger SOICR to determine if this contributes to the cardiotoxic nature of these compounds. Experimental Approach The impact of class I and II kinase inhibitors on SOICR was studied in HEK293 cells and ventricular myocytes using single‐cell Ca2+ imaging. A specific effect on RyR2 was confirmed using single channel recordings. Ventricular myocytes were also used to determine if drug‐induced changes in SOICR could be reversed using anti‐SOICR agents. Key Results Class I kinase inhibitors increased the propensity of SOICR. Single channel recording showed that this was due to a specific effect on RyR2. Class II kinase inhibitors decreased the activity of RyR2 at the single channel level but had little effect on SOICR. The promotion of SOICR mediated by class I kinase inhibitors could be reversed using the anti‐SOICR agent VK‐II‐86. Conclusions and Implications Part of the cardiotoxicity of class I kinase inhibitors can be assigned to their effect on RyR2 and increase in SOICR. Compounds with anti‐SOICR activity may represent an improved treatment option for patients.

Regulation of cardiac ryanodine receptor function by the cyclic-GMP dependent protein kinase G

“…Our finding that endogenous PKG activation also reduces the threshold for RyR2 Ca 2+ release in a manner dependent on S2808, therefore, aligns with these previous investigations ( Ullrich et al, 2012 ). The ∼2% decrease in the SOICR threshold induced by endogenous PKG activation is modest relative to the ∼5–12% reductions reported in previous studies of RyR2 function ( Jones et al, 2008 ; Chakraborty et al, 2019 ). However, given that a 5–12% reduction in the SOICR threshold is enough to trigger a large increase in SOICR frequency, Ca 2+ waves, and is pro-arrhythmic, it is perhaps unsurprising that physiological regulation of RyR2 by PKG results in a more modest change.…”

“…Our findings thus far suggest that pharmacological stimulation and inhibition of PKG both promote SOICR. The reason for the analogous effects of the pharmacological manipulations could be related to our recent finding that arrhythmogenic side-effects of therapies comprising class I kinase inhibitors arise due to a direct effect on RyR2 ( Chakraborty et al, 2019 ). Since KT 5823 is a class I kinase inhibitor, it was then pertinent to determine the possibility that this PKG inhibitor promotes SOICR independently of altering PKG activity.…”

“…Amount of FRET was determined from ratio of 535 and 480 nm emissions (YFP:CFP), as used previously ( Zhang et al, 2016 ). From each cell, the maximum and minimum Ca 2+ store levels were calculated from the maximal (F max ) and minimal FRET signals (F min ) induced by tetracaine and caffeine treatment, respectively ( Chakraborty et al, 2019 ). Ca 2+ store size was calculated from F max – F min and the threshold for SOICR (F SOICR ) was measured from the mean of the FRET signal preceding each SOICR event.…”

Human Atrial Fibrillation Is Not Associated With Remodeling of Ryanodine Receptor Clusters

“…In the healthy heart, this process is tightly controlled on a beat-to-beat basis to maintain a regular heartbeat. Abnormal Ca 2+ signaling within cardiomyocytes has been implicated in a number of cardiovascular diseases, often including altered function of RyR2 ( Wehrens and Marks, 2003 ; Chakraborty et al, 2019 ).…”

Pharmacogenomics of Pediatric Cardiac Arrest: Cisplatin Treatment Worsened by a Ryanodine Receptor 2 Gene Mutation

“…RyR2 is responsible for sarcoplasmic reticulum calcium release, hence its dysfunction leads to an impairment of intracellular calcium handling [26]. On the other hand, although a direct interaction between RyR2 and cisplatin cannot be ruled out [27], it is described that cisplatin induces an irreversible inhibition of SERCa2, reducing calcium reuptake in sarcoplasmic reticulum [28]. Broadening the comprehension of the complex biological system interactions during chemotherapy, we need to consider patient psychological distress, leading to anxiety and increased adrenergic burden, well described by the recent paradigm of "emotional chemobrain" [29].…”