Novel GSK-3 kinase inhibitor Pym-5 induces GSK-3β rather than GSK-3α-dependent melanogenesis in murine melanoma cells

Background: Glycogen synthase kinase-3 (GSK-3) inhibitors are considered to activate Wnt/beta-Catenin, which remains a controversial topic in melanoma treatment.Objective: Here, we have developed Pym-5, an attractive GSK-3 inhibitor. Using Pym-5 as a chemical tool to probe the GSK-3 biology, we aimed to investigate the potential of GSK-3 inhibition as a strategy of melanoma treatment and underlying mechanisms.Methods: Using pigment B16 and B16BL6 murine melanoma model in vitro and a zebrafish pigmentation model in vivo, we investigated Pym-5-meditaed activation of Wnt/beta-Catenin, melanogenesis and antitumor response in melanoma treatment.Results: We found that Pym-5 delayed the growth and promoted melanogenesis of melanoma cells. Pym-5 activated the transcription of beta-Catenin and responsive targets genes (AXIN2 and MITF), melanin biosynthesis genes (TYR, TYRP1 and TYRP2) and eventually elevated the production of melanin. Interestingly, genetic inactivation of GSK-3 beta, but not its paralogue GSK-3 alpha, compromised Pym-5-mediated melanogenesis in B16 and B16BL6 cells.Conclusion: These data provide insight into the potential therapeutic benefits obtained from activation of Wnt/beta-Catenin signaling pathway and how Pym-5 can regulate melanin production and the rationale for future clinical application of GSK-3 inhibitor in melanoma patients.(c) 2022 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.

Automated summary

The study found that the GSK-3 inhibitor Pym-5 can delay the growth of melanoma cells, promote melanin production, and achieve this effect by activating the Wnt/β-Catenin signaling pathway.