Effect of Vitamin D on Paclitaxel Efficacy in Triple-negative Breast Cancer Cell Lines.

Abstract

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer that disproportionately affects women with darker skin and is often treated with paclitaxel (PTX). Here, the effect of vitamin D on p53-positive DU4475 cells and its ability to decrease the IC50 of PTX in these cells were investigated. The growth inhibitory effects of vitamin D on DU4475 cells and the effect of PTX plus vitamin D on overall TNBC cell viability was assessed using CellTiter-Glo®. Vitamin D increased proliferation of DU4475 cells at low concentrations and lowered the IC50 of PTX. However, it did not change the IC50 of PTX in MDA-MB-231 cells which remained largely viable. The effect of vitamin D on DU4475 cell viability was different than in other TNBC cells. The effect of PTX on DU4475 cells was enhanced with vitamin D. MDA-MB-231 cells were relatively resistant to the effects of PTX.