Combined treatment of menadione plus calcitriol on Caco-2 Cancer Cells: antiproliferative effects

KOHAN R; COLLIN A; TOLOSA DE TALAMONI N; PICOTTO G

Mar del Plata

Congreso; LXI Reunión Anual de la SAIC; 2019

Sociedad Argentina de Investigación Clínica

Colorectal cancer (CRC) is the third most frequent and the fourth leading cause of cancer-associated mortalities worldwide. Effective targeted therapies based on the current knowledge of CRC are essential to achieve a successful treatment of this pathology. We have previously reported that oxidant drugs as menadione (MEN) increased tumour cell sensibility. Calcitriol (D) has well known antineoplastic actions on different tumor cells. However, the doses employed to reach this effect in vivo have undesirable hypercalcemic consequences. The aim of this study was to evaluate the effects of a combined MEN and D therapy on the viability of Caco-2 colon cancer cells and to study reactive oxygen species as possible inductors of oxidative stress (OS). Cells were treated with MEN, D, both or vehicle (ethanol). Crystal violet staining and microscopy evaluated antiproliferative effects. Cell migration was estimated by wound healing assay. Superoxide anion content, catalase (CAT) activity and cellular adhesion were also determined. One way ANOVA and Bonferroni as a post-hoc test were used as statistical methods. MEN and D inhibited Caco-2 growth in a time and dose-dependent manner. The antiproliferative effect began at 48h being higher at 96h. The selected concentration was 20µM MEN/200nM D. The combined treatment caused a dramatic reduction of viability (>80%) and a complete inhibition of cell migration. Morphological nuclear changes resulted compatible with cell death. Changes in cell adhesion were not observed. Superoxide anion content increased by the combined treatment concomitant with modifications in CAT activity. The antiproliferative effect of the combination was partially rescued exposing cells to the flavonoid naringin, a natural antioxidant. In conclusion, D enhances the antiproliferative effect of MEN on Caco-2 cells probably via the induction of OS. The study of this drug combination will continue in order to analyse future therapeutics applications.