Early studies have shown that vitamin C has a variety of health benefits, including the immune system, antioxidant effects, and cardiovascular health. Although vitamin C is an important nutrient for maintaining health, too much or too little can have adverse effects on health.

Melanoma (MM) is a malignant tumor that originates in pigmented cells of the skin and is the most dangerous type of skin cancer, although it has a low incidence and is more aggressive and metastatic. The incidence of melanoma has been on the rise over the past few decades.

Recently, Researchers from the University of South Florida in the United States and the University of Leicester in the United Kingdom published a paper entitled "Redox modulation of oxidatively-induced DNA damage by ascorbate enhances" in the journal Free Radical Biology and Medicine both in vitro and ex-vivo DNA damage formation and cell death in melanoma cells ".

Studies have shown that treating melanoma cancer cells with vitamin C can increase oxidant-induced DNA damage to cancer cells and promote cancer cell death, and this damage is proportional to the amount of melanin in the cells. And for normal skin cells, it plays a protective role.

In this study, the researchers established a group of MM cell lines with different pigmentation, used hydrogen peroxide as a model oxidant, and analyzed vitamin C to increase the likelihood of melanoma cell killing by enhancing oxidation-induced DNA damage.

The researchers tested levels of vitamin C-induced DNA damage in five cell lines and found that compared with normal skin cells, keratinocytes (HaCaT), the levels of endogenous DNA damage were generally higher in all MM cells, in order of damage severity: SK23 cells with high pigmentation, SK28 cells with moderate pigmentation, A375P and A375M cells without pigmentation, while HaCaT cells had the lowest degree of DNA damage.

In addition, the researchers analyzed the sensitivity of five cell lines to damage induced by an oxidant (hydrogen peroxide) and found that the damage sensitivity to hydrogen peroxide was consistent with the above.

Further analysis of intracellular oxidative species showed that MM cells exhibited much higher endogenous levels of intracellular oxidative species than HaCaT cells, and the sequencing of the five cell lines was consistent with DNA damage, damage sensitivity, and cytopigmentation.

Next, the researchers treated the cells with or without vitamin C and analyzed the potential regulatory effects of vitamin C on oxidation-induced DNA damage formation and cell killing.

The results showed that for all MM cells, the level of endogenous DNA damage induced by vitamin C treatment was significantly increased, while that of HaCaT cells was not significant, and the induced endogenous DNA damage was consistent with the above.

In addition, the level of vitamin C-induced nucleobase damage was highest in highly pigmented SK23 cells (18.5%) and lowest in non-pigmented A375P cells (14.2%).

Based on the fact that vitamin C can enhance peroxide induced endogenous DNA damage and nucleobase damage in MM cells, the researchers also analyzed the effect of vitamin C on DNA double strand breaks and found that for all MM cells, the level of DNA double strand breaks induced by vitamin C treatment increased significantly, but not for HaCaT cells. The sequence of the five cell lines is still consistent with the above.

Importantly, the researchers analyzed whether vitamin C enhanced peroxid-induced MM cell death, and found that vitamin C enhanced peroxid-induced killing of all MM cells, while playing a protective role in HaCaT cells, and the killing sequence was consistent with the above.

Finally, the study also found that vitamin C can enhance the efficacy of the existing melanoma drug Elesclomol, significantly enhancing the DNA damage of cancer cells induced by Elesclomol.

The researchers said that using vitamin C, which can increase DNA damage in cancer cells and lead to cancer cell death, may be a more effective way to treat melanoma, which still needs more clinical studies and trials to verify.

Given that vitamin C has been well studied and is known to be well tolerated, the researchers believe that clinicians could use vitamin C as a supplement to enhance existing treatments.

Taken together, this in vitro study shows that vitamin C can enhance oxidation-induced endogenous DNA damage, promote cancer cell death, while playing a protective role in normal skin cells, and enhance the efficacy of existing melanoma drugs, which merits further study.