Inhibitory effects on melanogenesis by thymoquinone are mediated through the β‑catenin pathway in B16F10 mouse melanoma cells

Abstract

Thymoquinone (TQ) is a component found in the seeds of Nigella sativa, an annual plant growing on the Mediterranean coast, and is known for its anticancer and anti-inflammatory effects. However, to date, at least to the best of our knowledge, limited studies are available examining the molecular mechanisms through which TQ inhibits melanogenesis. Accordingly, this study aimed to treat B16F10 mouse melanoma cells with TQ to investigate its apparent effects and its molecular regulatory mechanisms. Treatment of the B16F10 cells with 10, 15 and 20 µM of TQ for 48 h resulted in a dose-dependent decrease in the expression of microphthalmia-associated transcription factor (MITF), tyrosinase expression and tyrosinase activity, and these treatments simultaneously led to a decrease in the protein expression and transcription of β-catenin, a Wnt signaling pathway protein. Pre-treatment of the cells with the proteasome inhibitor, MG132, to confirm the inhibition of melanogenesis through the β-catenin pathway by TQ treatment resulted in an increase in the expression of β-catenin that was initially reduced by TQ, and the expression and activity of MITF and tyrosinase also increased. Pre-treatment with LiCl, which is known to inactivate glycogen synthase kinase 3β (GSK3β) by inducing the phosphorylation of the Ser-9 site, resulted in an increased phospho-GSK3β expression accompanied by β-catenin that was initially reduced by TQ, and the recovery of the expression and activity of tyrosinase was also confirmed. The transfection of S37A cDNA into B16F10 cells that overexpress β-catenin resulted in the recovery of β-catenin expression that was initially reduced by TQ, and this treatment also recovered the expression and activity of tyrosinase. When zebrafish eggs were treated with 1, 2.5 and 5 µM of TQ at 10 h following fertilization, their melanin content decreased in a dose-dependent manner. On the whole, these findings demonstrated that the inhibition of melanogenesis in B16F10 mouse melanoma cells by TQ treatment resulted from the inhibition of the β-catenin pathway and confirmed that TQ treatment inhibited melanogenesis in zebrafish.

Synthesis, Biological Evaluation, Migratory Inhibition and Docking Study of Indenopyrazolones as Potential Anticancer Agents

“…The antiproliferative properties of the IPOs were screened against melanoma cancer cells (B16F10) utilizing the standard 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide method. The procedure used to perform such activity is already reported elsewhere [51] . All of the IPO compounds and erlotinib (as a control) were given to the cells for 24 h at final concentrations ranging from 10 to 50 μM.…”

“…The procedure used to perform such activity is already reported elsewhere. [51] All of the IPO compounds and erlotinib (as a control) were given to the cells for 24 h at final concentrations ranging from 10 to 50 μM. To calculate the half-maximal inhibitory concentration values (IC 50 ), the results of cell viabilities were fitted in sigmoidal dose-response curves using non-linear regression analysis in GraphPad PRISM software (6.01).…”

Anticancer and Anti-Metastatic Role of Thymoquinone: Regulation of Oncogenic Signaling Cascades by Thymoquinone

“…The MITF promoter present in close vicinity to the common downstream exon is known as the M promoter and expressed selectively in melanocytes [ 36 ]. Proteasomal degradation of β-catenin occurs through GSK3β-mediated phosphorylation at the serine-33, serine-37, serine-45, and threonine-41 residues of β-catenin.…”

“…Thymoquinone dose-dependently reduced the expression of MITF and tyrosinase that was accompanied by decreased tyrosinase activity in B16F10 cells. Pre-treatment with LiCl resulted in an increase in the levels of p-GSK3β that led to the blockade of β-catenin degradation and increased the expression and activity of tyrosinase [ 36 ].…”

Essential Oils and Their Main Chemical Components: The Past 20 Years of Preclinical Studies in Melanoma

“…Valencene one of the major constituents of Ocotea dispersa EO decreased melanin content after UVB irradiation in B16-F10 cells [225]. A zebrafish embryo experimental model was also employed to demonstrate antimelanogenic activity of some EOs or their components, such as that from Dalbergia pinnata, which reduced tyrosinase activity and body pigmentation in zebrafish embryos [39], and thymoquinone which blocked melanogenesis also in B16-F10 mouse melanoma cells through the inhibition of the glycogen synthase kinase 3β (GSK3β)/β-catenin pathway [224]. Contrasting results were reported by the Zaidi KU group using the same experimental model and the same assays (tyrosinase activity and melanin production).…”