Ellagic Acid Controls Cell Proliferation and Induces Apoptosis in Breast Cancer Cells via Inhibition of Cyclin-Dependent Kinase 6.

Mohd Yousuf,Mohd Shahbaaz,Anas Shamsi,Gulam Mustafa Hassan,Asimul Islam,Afzal Hussain,Parvez Khan,Mohamed F Alajmi,Md Imtaiyaz Hassan,Qazi Mohd Rizwanul Haque

doi:10.3390/ijms21103526

Abstract

Cyclin-Dependent Kinase 6 (CDK6) plays an important role in cancer progression, and thus, it is considered as an attractive drug target in anticancer therapeutics. This study presents an evaluation of dietary phytochemicals, capsaicin, tocopherol, rosmarinic acid, ursolic acid, ellagic acid (EA), limonene, caffeic acid, and ferulic acid for their potential to inhibit the activity of CDK6. Molecular docking and fluorescence binding studies revealed appreciable binding affinities of these compounds to the CDK6. Among them, EA shows the highest binding affinity for CDK6, and thus a molecular dynamics simulation study of 200 ns was performed to get deeper insights into the binding mechanism and stability of the CDK6-EA complex. Fluorescence binding studies revealed that EA binds to the CDK6 with a binding constant of K = 107 M−1 and subsequently inhibits its enzyme activity with an IC50 value of 3.053 µM. Analysis of thermodynamic parameters of CDK6-EA complex formation suggested a hydrophobic interaction driven process. The treatment of EA decreases the colonization of cancer cells and induces apoptosis. Moreover, the expression of CDK6 has been downregulated in EA-treated human breast cancer cell lines. In conclusion, this study establishes EA as a potent CDK6 inhibitor that can be further evaluated in CDK6 directed anticancer therapies.

Highlights

Pathological stages of cancer cells are characterized by dysregulated cell proliferation, increased cell survival ability, loss of differentiation, accumulation of genetic mutation, and alteration in the metabolic pathways [1]
This study reports the binding efficiency and mechanism of interaction of ellagic acid (EA) to the Cyclin-Dependent Kinase 6 (CDK6) using a combined in silico and in vitro assays
The CDK6 gene from plasmid pcDNA was amplified by PCR, with NcoI and XhoI site at the 5 and 3 ends, respectively

Summary

Introduction

Pathological stages of cancer cells are characterized by dysregulated cell proliferation, increased cell survival ability, loss of differentiation, accumulation of genetic mutation, and alteration in the metabolic pathways [1]. Cancer therapeutics generally involves the identification of potential targets that play a direct or indirect role in the cell division and regulation of cell metabolism. Protein kinases regulate >80% of cellular pathways namely cell cycle progression, transcription, DNA repair, and metabolic events in different signaling cascades through phosphorylation/dephosphorylation and used as a potential drug target in cancer therapy [3]. Cyclin-dependent kinases (CDKs) belongs to serine/threonine-protein kinases and plays an important role in cell cycle progression [4]. CDK6 regulates glucose metabolism by inhibiting the activity of phosphofructokinase (PFK) and pyruvate kinase (PKM) of glycolysis through phosphorylation and subsequently reduces the production of reactive oxygen species (ROS) in cells [9]. The identification of a selective CDK-6 inhibitor may be used as therapeutic targeting of cancer cell growth and metabolic alterations [2,9]

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Conclusion