The enzyme protein kinase C ε (PKCε) plays an important role in pain signaling and represents a promising therapeutic target for the treatment of chronic pain. We designed and generated a small molecule inhibitor of PKCε, CP612, and examined its effect in a rodent model of chemotherapy-induced neuropathic pain produced by paclitaxel, which does not respond well to current therapeutics. In addition, many patients with chronic pain use opiates, which over time can become ineffective, and attempts to discontinue them can increase pain thereby promoting sustained opioid use. Therefore, we also investigated if CP612 alters pain due to opioid withdrawal. We found that CP612 attenuated hyperalgesia produced by paclitaxel, and it both prevented and reversed hyperalgesia induced by opioid withdrawal. It was not self-administered and did not affect morphine self-administration. These findings suggest that inhibition of PKCε is an effective, nonaddictive strategy to treat chemotherapy-induced neuropathic pain, with the added benefit of preventing increases in pain that occur as opioid treatment is discontinued. This latter property could benefit individuals with chronic pain who find it difficult to discontinue opioids.
Adriana Gregory-Flores, Ivan J.M. Bonet, Stève Desaivre, Jon D. Levine, Stanton F. McHardy, Harmannus C. de Kraker, Nicholas A. Clanton, Peter M. LoCoco, Nicholas M. Russell, Caleb Fleischer, Robert O. Messing, Michela Marinelli
Usage data is cumulative from April 2025 through April 2026.
| Usage | JCI | PMC |
|---|---|---|
| Text version | 2,167 | 299 |
| 463 | 65 | |
| Figure | 1,196 | 0 |
| Supplemental data | 225 | 5 |
| Citation downloads | 179 | 0 |
| Totals | 4,230 | 369 |
| Total Views | 4,599 | |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.