Trang Tran

Introduction. Skin cancer is the leading cancer diagnosed each year in the US.^1,5 It has taken a toll on US economy costing $8.1 billion dollars in the US for skin cancer treatment.^1,5 There is a number of risk factors that increasing one’s susceptibility for skin cancer: phenotypic markers like lighter skin tone, exposure to tar and sunlight,  frequency of skin tanning, and socioeconomic factors.² Polyphenols is a promising chemical for prevention of skin cancer especially polyphenols found in green tea.⁴ Methods In a study conducted, melanoma cells were treated with various concentrations of green tea polyphenols.⁴ Then their cell viability and colony formation were assayed using petri dishes.⁴ In another experiment, green tea polyphenols were assessed based on their histone deacetylation and acetylation activity using histone deacetylation assay and histone acetylation activity assay, respectively.⁴ Western blot was also used for that assessment. Following, that the concentration of tumor suppressor genes were assessed using western blot.⁴ Results With increasing concentrations of green tea polyphenols, melanoma cell viability and colony formation decreased.⁴ In addition to that, histone deacetylation activity decreased while histone acetylation activity increased with increasing green tea polyphenols. ⁴ Also, with increasing green tea polyphenol activity, oncogenic protein expression decreased while tumor suppressor increased.⁴ Conclusion Green tea polyphenols promotes acetylation of histones while decreasing histone deacetylation activity in melanoma cells.⁴ That thus increases expression of tumor suppressor genes when the histone is more acetylated and more open for expression. ⁴This altogether decreases the viability of melanoma cells which explains the decrease in cell viability of melanoma cells with increasing green tea polyphenol concentrations.⁴ Although, green tea polyphenols seemed promising in these results in the prevention of melanoma progression.⁴ Green tea polyphenols bioavailability through diet is very limited by the time it gets to the screen.³ Green tea polyphenols may be effective in melanoma prevention in combination with other anti-cancer drugs.³

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2. Gordon R. Skin cancer: an overview of epidemiology and risk factors. Semin Oncol Nurs. 2013; 29(3):160-9. doi: 10.1016/j.soncn.2013.06.0022
3. Mojzer EB, Hrncic MK, Skerget M, Knez Z, Bren U. Polyphenols: extraction methods, antioxidative action,bioavailability and anticarcinogenic effects. Molecules. 2016; 21(7): 901.
4. Prasad R, Katiyar SK. Polyphenols from green tea inhibit the growth of melanoma cells through inhibition of class I histone deacetylases and induction of DNA damage. Genes Cancer. 2015;6:49-61.
5. Sharma P, Montes De Oca MK, Alkeswani AR, McClees SF, Das T, Elmets CA, et al. Tea polyphenols for the prevention of UVB-induced skin cancer. Photodermatology, Photoimmunology & Photomedicine. 2017; 34(1):50-59. doi: 1.1111/phpp.12345 (in Pathology)