TY - JOUR
T1 - Penta-O-galloyl-beta-D-glucose induces S- and G1-cell cycle arrests in prostate cancer cells targeting DNA replication and cyclin D1
AU - Hu, Hongbo
AU - Zhang, Jinhui
AU - Lee, Hyo Jeong
AU - Kim, Sung Hoon
AU - Lü, Junxuan
N1 - Funding Information:
Hormel Foundation; National Institutes of Health (CA136953); Korea Ministry of Education, Science and Technology, Medical Research Center grant (R13-2007-019-00000-0).
PY - 2009
Y1 - 2009
N2 - We have recently shown that penta-1,2,3,4,6-O-galloyl-beta-D-glucose (PGG), a naturally occurring hydrolyzable gallotannin, inhibited the in vivo growth of human androgen-independent p53-mutant DU145 prostate cancer (PCa) xenograft in athymic nude mice without adverse effect on their body weight. We have also shown that PGG induced caspase-mediated apoptosis in the DU145 cells and the androgen-dependent human p53-wild-type LNCaP cells. Here, we investigated the cell cycle effects of PGG in these and other PCa cells. Our data show that treatment with subapoptotic doses of PGG induced S-arrest, whereas higher doses of PGG induced not only S-arrest but also G1 arrest. We show, for the first time, that irrespective of the p53 functional status of the PCa cell lines, PGG exerted a rapid (within 2 h) and potent inhibition (inhibitory concentration by 50% ∼6 μM) of 5-bromo-2′-deoxyuridine incorporation into S phase cells. In isolated nuclei, PGG inhibited DNA replicative synthesis with superior efficacy than a known DNA polymerase alpha inhibitor, aphidocolin. In addition to the S-arrest action, we have found a close association of downregulation of cyclin D1 with G1 arrest induced by PGG. Overexpressing this G1 cyclin abolished G1 arrest, but hastened the S-arrest induction by PGG. Together, our data indicate that PGG induced PCa S-arrest probably through DNA replicative blockage and induced G1 arrest via cyclin D1 downregulation to contribute to anticancer activity. Our data raise the hypothesis that PGG may be a novel inhibitor of DNA polymerases.
AB - We have recently shown that penta-1,2,3,4,6-O-galloyl-beta-D-glucose (PGG), a naturally occurring hydrolyzable gallotannin, inhibited the in vivo growth of human androgen-independent p53-mutant DU145 prostate cancer (PCa) xenograft in athymic nude mice without adverse effect on their body weight. We have also shown that PGG induced caspase-mediated apoptosis in the DU145 cells and the androgen-dependent human p53-wild-type LNCaP cells. Here, we investigated the cell cycle effects of PGG in these and other PCa cells. Our data show that treatment with subapoptotic doses of PGG induced S-arrest, whereas higher doses of PGG induced not only S-arrest but also G1 arrest. We show, for the first time, that irrespective of the p53 functional status of the PCa cell lines, PGG exerted a rapid (within 2 h) and potent inhibition (inhibitory concentration by 50% ∼6 μM) of 5-bromo-2′-deoxyuridine incorporation into S phase cells. In isolated nuclei, PGG inhibited DNA replicative synthesis with superior efficacy than a known DNA polymerase alpha inhibitor, aphidocolin. In addition to the S-arrest action, we have found a close association of downregulation of cyclin D1 with G1 arrest induced by PGG. Overexpressing this G1 cyclin abolished G1 arrest, but hastened the S-arrest induction by PGG. Together, our data indicate that PGG induced PCa S-arrest probably through DNA replicative blockage and induced G1 arrest via cyclin D1 downregulation to contribute to anticancer activity. Our data raise the hypothesis that PGG may be a novel inhibitor of DNA polymerases.
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U2 - 10.1093/carcin/bgp059
DO - 10.1093/carcin/bgp059
M3 - Article
C2 - 19269999
AN - SCOPUS:65549106509
SN - 0143-3334
VL - 30
SP - 818
EP - 823
JO - Carcinogenesis
JF - Carcinogenesis
IS - 5
ER -