l-Theanine inhibits melanoma cell growth and migration via regulating expression of the clock gene BMAL1

• Published in: European journal of nutrition 2022-03, Vol.61 (2), p.763-777
• Main Authors: Zhang, Ruyi, Zheng, Shuangning, Guo, Zhen, Wang, Yanan, Yang, Guocui, Yin, Zhimin, Luo, Lan
• Format: Article
• Language: English
• Subjects: Amino acids; Animals; Annexin V; Apoptosis; ARNTL Transcription Factors - genetics; ARNTL Transcription Factors - metabolism; ARNTL Transcription Factors - pharmacology; BMAL1 protein; Cancer; Cell growth; Cell migration; Cell Proliferation; Chemistry; Chemistry and Materials Science; Circadian rhythms; Clock gene; Dietary supplements; Glutamates - pharmacology; Green tea; Humans; Melanoma; Melanoma - drug therapy; Melanoma - genetics; Mice; Nutrition; Original Contribution; p53 Protein; Theanine; Transcription; Wound healing
• ISSN: 1436-6207; 1436-6215
• DOI: 10.1007/s00394-021-02677-y

Purpose l -Theanine is a unique non-protein amino acid found in green tea, which has been identified as a safe dietary supplement. It has been reported that l -theanine exerts various biological activities. In this study, we explored the anti-cancer effects of l -theanine on melanoma cells. Methods A375, B16–F10, and PIG1 cell lines were used in the present study. EdU labeling, TUNEL and Annexin V/PI staining, wound-healing, and transwell migration assay were performed to detect the effects of l -theanine on melanoma cell proliferation, apoptosis, and migration. Brain and muscle Arnt-like protein 1 (BMAL1) was knocked down in melanoma cells to evaluate if l -theanine plays the anti-cancer role through regulating circadian rhythm of melanoma cells. The western blot, qRT-PCR, and dual luciferase assay were performed to explore the mechanism involved in the effects of l -theanine on melanoma cells. Results l -Theanine apparently reduced the viability of melanoma cells. Further experiments showed that l -theanine attenuated the proliferation and migration, and promoted apoptosis of melanoma cells. l -Theanine significantly enhanced the expression of BMAL1 , a clock gene in melanoma cells. Down-regulation of BMAL1 suppressed the anti-cancer effects of l -theanine on melanoma cells. Further experiments indicated that the p53 transcriptional activity raised by l -theanine was dependent on BMAL1 expression in melanoma cells. Conclusion l -Theanine exerts the anti-cancer effect on melanoma cells through attenuating the proliferation and migration, and promoting apoptosis of them, which is dependent on the regulation of the clock gene Bmal1 in melanoma cells.