HY253, a novel decahydrofluorene analog, from Aralia continentalis, induces cell cycle arrest at the G1 phase and cytochrome c-mediated apoptosis in human lung cancer A549 cells.
OBJECTIVE
In the course of our screening for novel modulators on cell cycle progression and apoptosis as anticancer drug candidates, we isolated a novel compound HY253 with the molecular structure of 7,8a-divinyl-2,4a,4b,5,6,7,8,8a,9,9a-decahydro-1H-fluorene-2,4a,4b,9a-tetraol from the roots of Aralia continentalis. This study was designed to evaluate the detailed mechanisms of cell cycle arrest and the apoptotic induction of HY253 in human lung cancer A549 cells.


METHODS
To investigate the effects of HY253 on cell cycle progression in A549 cells, we measured DNA content of A549 cells treated with 35 microM of HY253 using flow cytometric analysis. Furthermore, TUNEL assay was used to examine apoptotic induction in A549 cells treated with 70 microM of HY253 for 24 and 48 h. The effects of HY253 on apoptosis-associated and cell cycle regulatory proteins in A549 cells were examined using Western blot analysis.


RESULTS
The flow cytometric analysis revealed an appreciable G(1) phase arrest in A549 cells treated with 35 microM of HY253. This HY253-induced G(1) phase arrest is associated with decreased expression of cyclin D and up-regulation of p21(CIP1), via p53 phosphorylation at Ser-15, which resulted in increased hypophosphorylated pRb in A549 cells. Furthermore, TUNEL assay and Western blot analysis revealed an appreciable apoptotic induction in A549 cells treated with 70 microM of HY253 for 48 h. This apoptotic induction in HY253-treated A549 cells is also associated with cytochrome c release from mitochondria which in turn resulted in the activation of caspase-9 and -3, and the cleavage of poly(ADP-ribose) polymerase (PARP).


CONCLUSIONS
These results demonstrate that HY253, a novel antiproliferative compound isolated from the roots of Aralia continentalis, induces cell cycle arrest at the G(1) phase and apoptosis in A549 cells. Based on these results, we suggest that HY253 may be a potent cancer chemotherapeutic candidate for use in treating human lung cancer cells via up-regulation and activation of p53 gene.
Oh
Ha Lim
HL
Department of Medical Genetics, College of Medicine, Hanyang University, 17 Haengdang-Dong, Sungdong-Gu, Seoul 133-791, Republic of Korea.
Lee
Dong-Keun
DK
Lim
Haeyoung
H
Lee
Chul-Hoon
CH
D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D027983:Aralia / Q000737:chemistry*; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D018797:Cell Cycle Proteins; D045744:Cell Line, Tumor; D056741:Cyclin D / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism*; D005434:Flow Cytometry; D005449:Fluorenes / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D016193:G1 Phase / Q000187:drug effects; D006801:Humans; D020287:In Situ Nick-End Labeling; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D008517:Phytotherapy; D018517:Plant Roots; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D012694:Serine; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D015854:Up-Regulation
C539892:7,8a-divinyl-2,4a,4b,5,6,7,8,8a,9,9a-decahydro-1H-fluorene-2,4a,4b,9a-tetraol; D000972:Antineoplastic Agents, Phytogenic; D018797:Cell Cycle Proteins; D056741:Cyclin D; D050759:Cyclin-Dependent Kinase Inhibitor p21; C416925:EID1 protein, human; D005449:Fluorenes; D009687:Nuclear Proteins; D012097:Repressor Proteins; D016159:Tumor Suppressor Protein p53; D012694:Serine; D045304:Cytochromes c; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases