Distinct Mechanism of Cysteine Oxidation-Dependent Activation and Cold Sensitization of Human Transient Receptor Potential Ankyrin 1 Channel by High and Low Oxaliplatin.

Takahito Miyake,Nobuaki Takahashi,Yasuo Mori,Keisuke Inoue,Kazuki Nagayasu,Hisashi Shirakawa,Tomohiro Numata,Satoshi Hamano,Takayuki Nakagawa,Shuji Kaneko,Saki Nakamura,Zhao Meng

doi:10.3389/fphys.2017.00878

Abstract

Oxaliplatin, a third-generation platinum-based chemotherapeutic agent, displays unique acute peripheral neuropathy triggered or enhanced by cold, and accumulating evidence suggests that transient receptor potential ankyrin 1 (TRPA1) is responsible. TRPA1 is activated by oxaliplatin via a glutathione-sensitive mechanism. However, oxaliplatin interrupts hydroxylation of a proline residue located in the N-terminal region of TRPA1 via inhibition of prolyl hydroxylase (PHD), which causes sensitization of TRPA1 to reactive oxygen species (ROS). Furthermore, PHD inhibition endows cold-insensitive human TRPA1 (hTRPA1) with ROS-dependent cold sensitivity. Since cysteine oxidation and proline hydroxylation regulate its activity, their association with oxaliplatin-induced TRPA1 activation and acquirement of cold sensitivity were investigated in the present study. A high concentration of oxaliplatin (1 mM) induced outward-rectifier whole-cell currents and increased the intracellular Ca2+ concentration in hTRPA1-expressing HEK293 cells, but did not increase the probability of hTRPA1 channel opening in the inside-out configuration. Oxaliplatin also induced the rapid generation of hydrogen peroxide, and the resultant Ca2+ influx was prevented in the presence of glutathione and in cysteine-mutated hTRPA1 (Cys641Ser)-expressing cells, whereas proline-mutated hTRPA1 (Pro394Ala)-expressing cells showed similar whole-cell currents and Ca2+ influx. By contrast, a lower concentration of oxaliplatin (100 μM) did not increase the intracellular Ca2+ concentration but did confer cold sensitivity on hTRPA1-expressing cells, and this was inhibited by PHD2 co-overexpression. Cold sensitivity was abolished by the mitochondria-targeting ROS scavenger mitoTEMPO and was minimal in cysteine-mutated hTRPA1 (Cys641Ser or Cys665Ser)-expressing cells. Thus, high oxaliplatin evokes ROS-mediated cysteine oxidation-dependent hTRPA1 activation independent of PHD activity, while a lower concentration induces cold-induced cysteine oxidation-dependent opening of hTRPA1 via PHD inhibition.

Highlights

Oxaliplatin (L-OHP), a third-generation platinum-based agent, is frequently used to treat locally advanced and metastatic cancers of the colon or rectum
These results indicate that L-OHP activates human TRPA1 (hTRPA1) when present at a concentration of at least 1 mM
The results of the present study showed that a high concentration of L-OHP (≥1 mM) evoked hTRPA1 activation via reactive oxygen species (ROS)-mediated cysteine oxidation, independently of prolyl hydroxylases (PHDs) inhibition, while both mechanisms are responsible for the cold-induced activation of hTRPA1 sensitized by the low concentration of L-OHP

Summary

Introduction

Oxaliplatin (L-OHP), a third-generation platinum-based agent, is frequently used to treat locally advanced and metastatic cancers of the colon or rectum. It increases the incidence of chemotherapy-induced peripheral neuropathy (CIPN), often resulting in chemotherapeutic dose delay or treatment discontinuation (Falcone et al, 2007; Miltenburg and Boogerd, 2014). The mechanisms underlying L-OHP-induced chronic CIPN can be explained, at least in part, by neurotoxicity in peripheral sensory neurons due to mitochondrial dysfunction and generation of reactive oxygen species (ROS) (Joseph and Levine, 2009; Di Cesare Mannelli et al, 2012; Azevedo et al, 2013) following accumulation of platinum in the dorsal root ganglia (DRG) (Screnci et al, 2000; Cavaletti et al, 2001). A body of evidence suggests that it is caused by alteration of the kinetics of the axonal voltage-gated Na+ channel (Sittl et al, 2012; Deuis et al, 2013) and/or activation of transient receptor potential ankyrin 1 (TRPA1) (Nassini et al, 2011; Zhao et al, 2012)

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Results

Conclusion