Vitamin C may exert variable effects on viability and proliferation of HeLa cells exhibiting high and low chromosomal instability

Abstract

Background. Chromosomal instability (CIN), defined as abnormality in chromosome structure or number, is the hallmark of malignancies. The role of vitamin C in cancer treatment is controversial and its effect on CIN is still an open field of research. In this work, we tried to study the effect of high-dose L-ascorbic acid (L-AA) on CIN-induced (CINhi = CIN high) and non-CIN-induced (CINlo = CIN low) cervical cancer cells. Objectives. The aim of this study was to explore the effect of high-dose L-AA on CIN in the cervical cancer cell line (HeLa) cells. Material and methods. The HeLa cells (CINhi and CINlo) were treated with 2 doses (5 mM and 8 mM) of L-AA for 24 h and 48 h. They were then analyzed by micronucleus (MN) scoring, cell ploidy and flow cy-tometry, the latter regarding γH2AX expression. Cell viability was assessed by the methylthiazol tetrazolium (MTT) and Annexin V assays. Results. Treatment of CINhi cells with L-AA led to a decrease in MN score (colchicine - 71.5 ±4.95, 67.5 ±0.71; L-AA (5 mM) - 49 ±7.07, 46.5 ±4.95; L-AA (8 mM) - 42 ±9.89, 41 ±1.41, at 24 h and 48 h, respectively; p < 0.05). Treatment of CINlo cells with L-AA resulted in increased MN score (5 mM - 45 ±7.07, 36 ±4.24; 8 mM - 34.5 ±4.95, 31 ±1.41, at 24 h and 48 h, respectively; control - 15.5 ±0.71, 12.5 ±0.71; p < 0.05) and reduction in cancer cell viability (control - 100%; L-AA (5 mM) - 76.32% ±28.73, 72.74% ±20.30; L-AA (8 mM) - 66.14% ±19.13, 66.99% ±19.99, at 24 h and 48 h, respectively; p < 0.05). The expression of γH2AX was high in both groups at 48 h (mean CINhi = 19.42%, CINlo = 21.14%; control = 1.19% and 1.58%, respectively) with the 8 mM dose of L-AA. Conclusions. L-ascorbic acid was found to have a differential effect on CINhi and CINlo HeLa cells, which may be due to differences in oxidation status of these 2 categories.