Hexokinase 2 Inhibition and Biological Effects of BNBZ and Its Derivatives: The Influence of the Number and Arrangement of Hydroxyl Groups.

Karolina Matczak,Mateusz D. Tomczyk,Grzegorz Dzido,Radosław Kitel,Magdalena Łabieniec-Watała,Karolina Juszczak,Agnieszka Marczak,Anna Kubicka,Krzysztof Walczak,Serafin Zawadzki

doi:10.3390/ijms23052616

Abstract

Hexokinase 2 (HK2), an enzyme of the sugar kinase family, plays a dual role in glucose metabolism and mediating cancer cell apoptosis, making it an attractive target for cancer therapy. While positive HK2 expression usually promotes cancer cells survival, silencing or inhibiting this enzyme has been found to improve the effectiveness of anti-cancer drugs and even result in cancer cell death. Previously, benitrobenrazide (BNBZ) was characterized as a potent HK2 inhibitor with good anti-cancer activity in mice, but the effect of its trihydroxy moiety (pyrogallol-like) on inhibitory activity and some cellular functions has not been fully understood. Therefore, the main goal of this study was to obtain the parent BNBZ (2a) and its three dihydroxy derivatives 2b–2d and to conduct additional physicochemical and biological investigations. The research hypothesis assumed that the HK2 inhibitory activity of the tested compounds depends on the number and location of hydroxyl groups in their chemical structure. Among many studies, the binding affinity to HK2 was determined and two human liver cancer cell lines, HepG2 and HUH7, were used and exposed to chemicals at various times: 24 h, 48 h and 72 h. The study showed that the modifications to the structures of the new BNBZ derivatives led to significant changes in their activities. It was also found that these compounds tend to aggregate and exhibit toxic effects. They were found to contribute to: (a) DNA damage, (b) increased ROS production, and (c) disruption of cell cycle progression. It was observed that, HepG2, occurred much more sensitive to the tested chemicals than the HUH7 cells; However, regardless of the used cell line it seems that the increase in the expression of HK2 in cancer cells compared to normal cells which have HK2 at a very low level, is a serious obstacle in anti-cancer therapy and efforts to find the effective inhibitors of this enzyme should be intensified.

Highlights

In contrast to normally differentiated cells, which generate energy for cellular processes relying on oxidative phosphorylation (OXPHOS), most cancer cells instead use aerobic glycolysis, a phenomenon known as the Warburg effect
Hexokinase 2 (HK2) plays a key role in tumor initiation and development as the first enzyme in the glycolysis pathway that phosphorylates glucose to G6P, introducing glucose into pathways required for anabolic activities in cancer cells [3]
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Summary

Introduction

In contrast to normally differentiated cells, which generate energy for cellular processes relying on oxidative phosphorylation (OXPHOS), most cancer cells instead use aerobic glycolysis, a phenomenon known as the Warburg effect. An enhanced glucose metabolic rate is required to meet the biosynthetic and bioenergetic demands of rapidly growing and proliferating cancer cells In this context, aerobic glycolysis seems to be an inefficient way to generate energy as the maximum net yield is 2.73 moles of ATP per mole of substrate for pyruvate plus malate oxidation, while the maximum total yield is 33 moles of ATP for complete glucose oxidation [1]. Cancer cells can compensate lower ATP production per mole of substrate using a pathway with high rate but low yield especially when they are in resource competition with normal cells that produce ATP at a higher yield but a lower rate.

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Discussion

Conclusion