Differences in Subcellular Distribution of Catechol-O-Methyltransferase and Tyrosinase in Malignant Melanoma

Correlations of psychological distress with plasma cytokine levels and gene mutations in acral and non-acral melanoma

BACKGROUND

The presence of psychological distress has negatively affected the course and prognosis of melanoma. Psychological distress is influenced by cytokines and gene mutations, particularly in cancer, but no studies have investigated this phenomenon in melanoma patients. This study investigated the correlations of psychological distress, plasma cytokine levels, and gene mutations in melanoma patients, focusing on melanoma sites and TNM stages.

METHODS

This study prospectively evaluated melanoma patients who visited Chonnam National University Hwasun Hospital from September 2020 to March 2021. Melanoma sites were divided into acral and non-acral sites. Anxiety and depression were evaluated using the Hospital Anxiety and Depression Scale, and quality of life was evaluated with EuroQol-5 Dimensions. Plasma cytokine levels, and depression- and cytokine-related gene mutations were analyzed.

RESULTS

This study included 151 melanoma patients. Anxiety was found in 14.6% of the patients, and depression in 29.8%. The melanoma sites were not significantly associated with anxiety, depression, or quality of life. However, psychological distress was significantly associated with the plasma cytokines IL-2, IL-4, IL-5, IL-10, IL-12, TNF-α and IFN-γ. COMT, SLC6A4, SLC6A3, and IL-12b gene mutations were also associated with melanoma sites and TNM stage, anxiety, and QOL.

CONCLUSION

Psychological distress was associated with plasma cytokine levels and depression- and cytokine-related gene mutations. Using psychiatric intervention and emotional support, cytokine levels related to melanoma can be changed, which may have positive effects on the prognosis and treatment of melanoma. More careful follow-up, evaluation, and management are needed for patients with gene mutations.

Catechol-O-methyltransferase as a target for melanoma destruction?

Catechols may interfere in melanogenesis by causing increased levels of toxic quinones. Several catechols and known inhibitors of the enzyme catechol-O-methyltransferase (COMT) were therefore tested for their toxicity towards a pigmented melanoma cell line, UCLA-SO-(M14). The inhibition of thymidine incorporation as a result of exposure to the compounds was measured. All agents were compared to 4-hydroxyanisole (4HA), a depigmenting agent extensively studied as an antimelanoma drug. The compounds were also tested on the epithelial cell line, CNCM-I-(221) in the presence and absence of tyrosinase. All the compounds were more effective than 4HA towards the M14-cells at either 10(-4) M or 10(-5) M. The toxicity of 4HA towards the 221-cells was shown to be completely dependent on the presence of tyrosinase. Effects of the test agents on the 221-cells were also observed in the absence of tyrosinase. Although some of them were shown to be good substrates for tyrosinase only small changes in toxicity were observed as a result of the presence of the enzyme in comparison with 4HA. No direct correlation of the toxicity of the agents and COMT inhibition was observed. The possible mode of action of the compounds through inhibition of COMT and interference in melanogenesis is discussed together with other possibilities and factors involved.