Noninvasive and Safe Cell Viability Assay for Breast Cancer MCF-7 Cells Using Natural Food Pigment.

Kyohei Yamashita,Ryoma Tagawa,Eiji Tokunaga,Yoshikazu Higami

doi:10.3390/biology9080227

Abstract

A dye exclusion test (DET) was performed to determine the viability of human breast cancer cells MCF-7, using natural food pigments as compared with trypan blue (TB), a typical synthetic dye for DET known to exhibit teratogenicity and cytotoxicity. We demonstrated that Monascus pigment (MP) is noninvasive to living cells and can effectively stain only dead cells. This study is the first verification of the applicability of MP to cancer cells. The appropriate MP concentration was 0.4% (0.02% as the concentration of pure MP) and all the dead cells were stained within 10 min. We found that the cell proliferation or the reduced nicotinamide adenine dinucleotide (NADH) activity of living cells was maintained over 48 h. Although 0.1% TB did not show an increase in dead cells, a marked decrease in NADH activity was confirmed. In addition, even when MP coexisted with cisplatin, staining of dead cells was maintained for 47 h, indicating stability to drugs (reagents). The cost of MP is estimated to be about 1/10 of TB. The fact that MP can be used as a cell viability determination reagent for Euglena and Paramecium, as shown in preceding papers, and also for MCF-7, as shown in this paper, indicates the possibility of application in more cells of different species.

Highlights

In vitro tests are faster, easier to perform and to quantify, usually cheaper, and allow studies of isolated steps [1]
There should be a potential demand for a long-term, noninvasive, safe viability assay of the same sample
MCF-7 cells are widely used in studies of estrogen receptor. To verify that this method is applicable to a wide variety of cells, first, we examined whether natural pigments are not toxic to human breast cancer cells MCF-7 cells in the presence or absence of cisplatin and if they can be replaced with conventional synthetic dyes for viability assay

Summary

Introduction

In vitro tests are faster, easier to perform and to quantify, usually cheaper, and allow studies of isolated steps [1]. Chemical substances such as drugs and pesticides have various cytotoxic mechanisms such as destruction of cell membranes and prevention of protein synthesis [2]. To identify cell death caused by these toxicities, the fields of toxicology and pharmacology require inexpensive, reliable, and reproducible short-term cytotoxicity and cell viability assays. In the case of a harmless method for assessing the viability of a target cell, more detailed information can be obtained by long-term monitoring of the viability. There should be a potential demand for a long-term, noninvasive, safe viability assay of the same sample

Methods

Results

Discussion

Conclusion