[Frontiers in Bioscience E3, 1337-1348, June 1, 2011]

Acylated catechin derivatives: inhibitors of DNA polymerase and angiogenesis

Yoshiyuki Mizushina1,2, Akiko Saito3, Keiko Horikawa4, Noriyuki Nakajima4, Akira Tanaka5, Hiromi Yoshida1,2, Kiminori Matsubara2,6

1Laboratory of Food and Nutritional Sciences, Department of Nutritional Science, Kobe-Gakuin University, Nishi-ku, Kobe, Hyogo 651-2180, Japan, 2Cooperative Research Center of Life Sciences, Kobe-Gakuin University, Chuo-ku, Kobe, Hyogo 651-8586, Japan, 3Department of Applied Chemistry, Faculty of Engineering, Osaka Electro-Communication University, Neyagawa-shi, Osaka 572-8530, Japan, 4Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan, 5Department of Bioresources Science, College of Technology, Toyama Prefectural University, Kosugi, Toyama 939-0398, Japan, 6Department of Human Life Science Education, Graduate School of Education, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8524, Japan

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and Methods
3.1. Materials
3.2. Preparation of DNA polymerases and other DNA metabolic enzymes
3.3. DNA polymerase assays
3.4. Other DNA metabolic enzymes assays
3.5. Cell culture and measurement of cell viability
3.6. Ex vivo angiogenesis assay
3.7. Endothelial cells
3.8. HUVEC tube formation assay
4. Results
4.1. In vitro DNA polymerase inhibition
4.1.1. Effect of the derivatives of 3-O-acylcatechin and 3-O-acylepicatechin on the activities of mammalian pol activity
4.1.2. Effects of compound 8 (C-C18) on various pols and other DNA metabolic enzymes
4.1.3. Mode of inhibition of mammalian pols alpha and beta by compound 8 (C-C18)
4.2. Suppression of cultured cell growth
4.3. Angiogenesis inhibition
4.3.1. Effect of the derivatives of 3-O-acylcatechin and 3-O-acylepicatechin on ex vivo angiogenesis
4.3.2. Effect of compound 8 (C-C18) on HUVEC tube formation
5. Discussion
6. Acknowledgements
7. References

1. ABSTRACT

Catechins in green tea display anti-cancer and anti-angiogenesis activities. We previously found that some catechins, such as epigallocatechin-3-O-gallate (EGCG), inhibit the activities of eukaryotic DNA polymerases (pols) (Y. Mizushina et al.: Structural analysis of catechin derivatives as mammalian DNA polymerase inhibitors. Biochem Biophys Res Commun 333, 101-109 (2005)). In this study, we discuss the effects of chemical modifications of catechin and epicatechin that enhance their anti-cancer and anti-angiogenic activities based on pol inhibition. Catechins conjugated with fatty acid (3-O-acylcatechins) are stronger inhibitors of mammalian pol than epicatechins conjugated with fatty acid (3-O-acylepicatechins). Moreover, 3-O-acylcatechins are more potent inhibitors of cultured cell growth both of the human colon carcinoma cell line (HCT116 cells) and human umbilical vein endothelial cell (HUVEC) line, as well as angiogenesis by comparison with 3-O-acylepicatechins. Catechin conjugated with stearic acid ((2R,3S)-3',4',5,7-tetrahydroxyflavan-3-yl octadecanoate; C-C18) was the strongest inhibitor in replicative pol alpha and repair-related pol beta, as well as the cultured cell growth and angiogenesis assays in the compounds tested. C-C18 also suppressed HUVEC tube formation on reconstituted basement membrane suggesting that it affected not only pols but also signal transduction pathways in HUVECs. These data indicate that the acylated catechins target both pols and angiogenesis as anti-cancer agents. Moreover, the results suggest that acylation of catechin is an effective chemical modification to improve the anti-cancer activity of catechin.