A Novel Combination of Withaferin A and Sulforaphane Inhibits Epigenetic Machinery, Cellular Viability and Induces Apoptosis of Breast Cancer Cells.

Kendra Royston,Trygve Tollefsbol,Kayla Lewis,Neha Udayakumar

doi:10.3390/ijms18051092

Kendra Royston, Trygve Tollefsbol + Show 2 more

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https://doi.org/10.3390/ijms18051092

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Abstract

With cancer often classified as a disease that has an important epigenetic component, natural compounds that have the ability to regulate the epigenome become ideal candidates for study. Humans have a complex diet, which illustrates the need to elucidate the mechanisms of interaction between these bioactive compounds in combination. The natural compounds withaferin A (WA), from the Indian winter cherry, and sulforaphane (SFN), from cruciferous vegetables, have numerous anti-cancer effects and some report their ability to regulate epigenetic processes. Our study is the first to investigate the combinatorial effects of low physiologically achievable concentrations of WA and SFN on breast cancer cell proliferation, histone deacetylase1 (HDAC1) and DNA methyltransferases (DNMTs). No adverse effects were observed on control cells at optimal concentrations. There was synergistic inhibition of cellular viability in MCF-7 cells and a greater induction of apoptosis with the combinatorial approach than with either compound administered alone in both MDA-MB-231 and MCF-7 cells. HDAC expression was down-regulated at multiple levels. Lastly, we determined the combined effects of these bioactive compounds on the pro-apoptotic BAX and anti-apoptotic BCL-2 and found decreases in BCL-2 and increases in BAX. Taken together, our findings demonstrate the ability of low concentrations of combinatorial WA and SFN to promote cancer cell death and regulate key epigenetic modifiers in human breast cancer cells.

Highlights

Epigenetics is the study of changes in gene expression caused by mechanisms other than changes in the underlying DNA sequence
In this study we aimed to investigate the impact of combinatorial SFN and Withaferin A (WA) on MCF-7 estrogen receptor-positive (ER (+)) and MDA-MB-231 ER (−) breast cancer cell proliferation in conjunction with their role in the epigenetic gene expression of DNMT1, DNMT3A, DNMT3B and histone deacetylase1 (HDAC1)
Where HDAC1 was decreased with our compounds in comparison to the Food and Drug Administration (FDA)-approved chemotherapeutic SAHA (Figure 9A,D) we demonstrate an induction of BAX (Figure 9B,E) and a reduction of BCL-2 with SFN + WA (Figure 9C,F)

Summary

Introduction

Epigenetics is the study of changes in gene expression caused by mechanisms other than changes in the underlying DNA sequence. Many studies have taken an epigenetic approach to cancer prevention by focusing on the modulation of the expression of key epigenetically controlled genes [1]. It is known that several cancers are characterized by an overexpression of histone deacetylases (HDACs) and DNA methyltransferases (DNMTs). Each of these epigenetic enzymes has varying roles. The inhibition and regulation of these enzymes, as well as the genes that control their expression, are at least partially responsible for decreased cell viability and regulation of tumor suppressor genes in several cancer types [2,3,4]. Due to the promising role of the inhibition of epigenetic modifiers in cancer cell death, chemotherapies with epigenetic targets have been US Food and Drug Administration (FDA)-approved and are being used in the clinical setting [5]

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