%0 Journal Article %T Genistein Derivatives Regioisomerically Substituted at 7-O- and 4¡ä-O- Have Different Effect on the Cell Cycle %A A. Byczek %A J. Zawisza-Puchalka %A A. Gruca %A K. Papaj %A G. Grynkiewicz %A M. Rusin %A W. Szeja %A A. Rusin %J Journal of Chemistry %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/191563 %X Our previous studies on antiproliferative properties of genistein derivatives substituted at C7 hydroxyl group of the ring A revealed some compounds with antimitotic properties. The aim of this work was to synthesize their analogues substituted at the 4¡ä-position of the ring B in genistein and to define their antiproliferative mechanism of action in selected cancer cell lines in vitro. C4¡ä-substituted glycoconjugates were obtained in a three-step procedure: (1) alkylation with an ¦Ø-bromoester; (2) deacylation; (3) Ferrier-type rearrangement glycosylation with acylated glycals. Biological effects including antiproliferative effects of the compounds, cell cycle, DNA lesions (ATM activation, H2A.X phosphorylation, and micronuclei formation), and autophagy were studied in human cancer cell lines. Some of the tested derivatives potently inhibited cell proliferation. The presence of a substituent at the 4¡ä-position of the ring B in genistein correlated to a p53-independent G1 cell-cycle arrest. The derivatives substituted at C4¡ä did not induce DNA lesions and appeared to be nongenotoxic. The tested compounds induced autophagy and caused remarkable decrease of cell volume. 1. Introduction Flavonoids are naturally occurring plant polyphenols found in abundance in fruits, vegetables, and plant-derived beverages [1]. Epidemiological studies have shown that the intake of certain vegetables, fruits, and tea in the daily diet provides effective cancer prevention. This class of compounds have been found to arrest cell-cycle progression either at G1/S or at G2/M boundaries [2] and inhibit cell proliferation. The inhibition of cell-cycle is a result of inhibition of different cell-cycle kinases or activation of cell-cycle control checkpoints [3¨C5]. Beneficial influence of genistein on human health, resulting from its interaction with multiple molecular targets [6, 7] combined with opportunities of chemical functionalization, makes this molecule very attractive as a lead compound. The structure of genistein molecule enables different types of derivatizations, that is, modification of the isoflavone skeleton or manipulation functional groups around the isoflavone core, which may improve its affinity towards molecular targets [8]. There are many examples of genistein derivatives which show better pharmacological characteristics comparing to the parent compound genistein, including altered binding affinities to estrogen receptors (ERs) [9] and enhanced antiproliferative activities [10¨C14]. Among genistein derivatives showing enhanced antiproliferative activity are %U http://www.hindawi.com/journals/jchem/2013/191563/