Abstract
Purpose:
Resveratrol (3,5,4′-trihydroxytrans-stillbene) is a stillbenoid non-flavonoid contained in various natural compounds, particularly in the skin of grapes. It is a powerful antioxidant and has been proven in vitro to inhibit proliferation and induce cell death in a number of cancer cell lines. Zahid et al. (2011) had previously shown that resveratrol combined with N-acetylcysteine (NAC) had increased potency in the inhibition of cancer emergence and proliferation. The purpose of this study was to assess whether the cytotoxic effect of resveratrol could be enhanced by the addition of NAC on uveal melanoma cells as well.
Methods:
A metastatic (C918) and a non-metastatic (SP6.5) human uveal melanoma cell lines were treated with resveratrol (10, 30, 100 and 300 μM), NAC (0.3, 1, 3, 10 and 30 mM) and a combination of the two compounds (resveratrol at 30 μM with NAC at 1, 3, 10 and 30 mM). The effects of these compounds on cell viability were assessed by using the MTT (3-[4,5-dimethylthiazol-2-yl]2,5-diphenyltetrazolium bromide) assay.
Results:
Resveratrol reduced cell viability of cultured human uveal melanoma cells in a dose-dependent manner (10, 30, 100 and 300 μM ) and time-dependent manner (3-48 hr), with IC50 at 91.8 ±16.2 μM and 62.7 ±32.0 μM in SP6.5 and C918 cell lines, respectively. NAC, on the other hand, reduced cell viability in a dose dependent manner only in the non-metastatic cell line (SP6.5) with IC50 at 18.7 ± 2.6 mM, but did not affect cell viability of the metastatic cell line up to 30 mM. The combination of resveratrol and NAC was not effective on both SP6.5 and C918 cell lines, e.g., cell viability in SP6.5 treated with resveratrol (30 μM ) and resveratrol (30 μM ) with NAC (10 mM) was 66.7 ± 7.4 % and 80.0 ± 10.8%, respectively (P = 0.162), indicating that the addition of NAC did not increase the cytotoxic effect of resveratrol.
Conclusions:
Resveratrol has a powerful cytotoxic effect on both cell lines of uveal melanoma, whereas NAC is effective only in the non-metastatic cell line (SP6.5). Addition of NAC to resveratrol did not enhance cytotoxic effect in uveal melanoma cells.
Keywords: 589 melanoma •
744 tumors •
637 pathology: experimental