Changes in Lactate Production, Lactate Dehydrogenase Genes Expression and DNA Methylation in Response to Tamoxifen Resistance Development in MCF-7 Cell Line.

Lama Hamadneh,Sokiyna Albustanji,Bashaer Abu-Irmaileh,Shahd Tarawneh,Abdel Qader Al-Bawab,Ala A Alhusban,Lara Al-Lakkis

doi:10.3390/genes12050777

Lama Hamadneh, Sokiyna Albustanji + Show 5 more

Open Access

https://doi.org/10.3390/genes12050777

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Abstract

Lactate dehydrogenase (LDH) is a key enzyme in the last step of glycolysis, playing a role in the pyruvate-to-lactate reaction. It is associated with the prognosis and metastasis of many cancers, including breast cancer. In this study, we investigated the changes in LDH gene expression and lactate concentrations in the culture media during tamoxifen resistance development in the MCF-7 cell line, and examined LDHB promoter methylation levels. An upregulation of 2.9 times of LDHB gene expression was observed around the IC50 concentration of tamoxifen in treated cells, while fluctuation in LDHA gene expression levels was found. Furthermore, morphological changes in the cell shape accompanied the changes in gene expression. Bisulfate treatment followed by sequencing of the LDHB promoter was performed to track any change in methylation levels; hypomethylation of CpG areas was found, suggesting that gene expression upregulation could be due to methylation level changes. Changes in LDHA and LDHB gene expression were correlated with the increase in lactate concentration in the culture media of treated MCF-7 cells.

Highlights

Breast cancer remains a major health problem in most parts of the world, despite the advances achieved in the field [1]
Some studies reported that lactate dehydrogenase B (LDHB) gene expression was found to be reduced in many commonly used breast cancer cell lines due to the hypermethylation of the promoter area leading to gene silencing [14], while other researchers reported that upregulated gene and protein expression are seen in triple-negative cells in comparison to luminal breast cancer cells [15]
Lactate dehydrogenase A and B gene expression levels were determined during tamoxifen resistance development in MCF-7 cell lines and correlated with the concentration of lactate secreted to the culture media

Summary

Introduction

Breast cancer remains a major health problem in most parts of the world, despite the advances achieved in the field [1]. Breast cancer mortality rates were significantly reduced by about one third through the first 15 years of follow up among tamoxifen treated patients [4,5]. Some studies reported that lactate dehydrogenase B (LDHB) gene expression was found to be reduced in many commonly used breast cancer cell lines due to the hypermethylation of the promoter area leading to gene silencing [14], while other researchers reported that upregulated gene and protein expression are seen in triple-negative cells in comparison to luminal breast cancer cells [15]. Lactate dehydrogenase A and B gene expression levels were determined during tamoxifen resistance development in MCF-7 cell lines and correlated with the concentration of lactate secreted to the culture media

Materials and Methods

Findings

Conclusions