Effect of peripheral endothelin‐1 concentration on carcinoma‐induced pain in mice

Abstract

In this study, we investigated the role of the peripheral endothelin-1 (ET-1) concentration in a cancer pain model. To test the hypothesis that the concentration of ET-1 in the tumor microenvironment is important in determining the level of cancer pain we used two cancer pain mouse models that differed significantly in production of ET-1. The two mouse cancer models were produced by injection of cells derived from a human oral squamous cell carcinoma (SCC) and melanoma into the hind paw of female mice. Pain, as indicated by reduction in withdrawal thresholds in response to mechanical stimulation, was significantly greater in the SCC group than the melanoma group. The peripheral concentration of ET-1 within the cancer microenvironment was significantly greater in the SCC group. Intra-tumor expression of both ET-1 mRNA and ET-1 protein were significantly higher in the SCC model compared to the melanoma model. ET receptor antagonism was effective as an analgesic for cancer pain in the SCC model only. To address the potential confounding factor of tumor volume we evaluated the contribution of tumor volume to cancer pain in the two models. The mean volumes of the tumors in the melanoma group were significantly greater than the tumors in the SCC group. In both groups, the pain level correlated with tumor volume, but the correlation was stronger in the melanoma group. We conclude that ET-1 concentration is a determinant of the level of pain in a cancer pain mouse model and it is a more important factor than tumor volume in producing cancer pain. These results suggest that future treatment regimens for cancer pain directed at ET-1 receptor antagonism show promise and may be tumor type specific.

Epigenetic mechanisms of chronic pain

“…These mechanisms include DNA methylation, several types of histone modifications (e.g., acetylation, methylation, phosphorylation, and ADP-ribosylation), and expression of microRNAs (miRNAs). Epigenetic mechanisms can be dynamic and responsive to changes in experience, thus representing a complex interplay between an organism and its environment [32, 33]. Acetylation of most histone subunits, at any of several Lysine (Lys) residues, typically promotes gene transcription, while histone methylation can either repress or activate gene transcription depending on the amino acid residue undergoing methylation.…”

OPRM1 Methylation Contributes to Opioid Tolerance in Cancer Patients

“…We have used other cancer cell lines, including melanoma and breast cancer, which do not produce the same profound nociceptive effects in the mouse model. 20,33 We analyzed neuronal tissue in the mice rather than peripheral leukocytes. Although the discrepancy in tissues used between human subjects and animals might seem to weaken the translational potential of the study, a direct comparison between the human peripheral leukocyte OPRM1 methylation and mouse peripheral leukocyte Oprm1 methylation is not possible.…”

Nanotechnology-based drug delivery systems for treatment of oral cancer: a review

“…44 In patients with OSCC, the ET-1 levels are higher in the tumor microenvironment, and nociception was reported with mechanical stimuli parallel to the mechanical allodynia. 45,46 The role of ET-1 in oral cancer pain was confirmed and characterized in a mouse model by Pickering et al 47 and the ET-1 concentration was a more important factor than tumor volume in establishing cancer pain.…”