The Effect of Antioxidants N-Acetylcysteine and Vitamin E on Colorectal Cancer Cell Invasion + Migration in a Scratch Assay

It is a commonly held belief that antioxidants would blunt the formation and progression of cancer cells. This has prompted nutritionists and clinicians to recommend antioxidants in large doses. However, the evidence regarding the efficacy of antioxidants on the incidence and prognosis of cancer are mixed. Furthermore, the data regarding the effect of antioxidants on colorectal cancer cell proliferation and migration are limited. The aim of the present study is to determine the effect of antioxidants N-acetyl-L-cysteine (NAC) and α-tocopherol (Vitamin E), alone or in combination, on colorectal cancer cell invasivity using the classical wound healing (scratch) assay. The scratch wound closure was assayed at baseline, 0, 24, and 48 hours after treatment and percent wound closure from baseline was determined. Interestingly, the cells treated with a combination of NAC+ and α-tocopherol are substantially more invasive than the cells simply treated with NAC+ or α-tocopherol alone despite receiving a two-fold higher dose of each antioxidant. In contrast, cells treated with α-tocopherol did demonstrate modestly enhanced migratory capacity compared with control cells; however, this was not statistically significant (p=0.09, n=3). NAC appeared to have little or no effect on cell proliferation and migration over control cells. Indeed, these findings indicate that antioxidant therapy substantially augments the migratory capacity of colorectal cancer cells. These findings complement and extend the results of previous studies, which have found that antioxidants, when used individually, can accelerate tumor metastatic activity and invasiveness.