NCPMF-60 induces G2/M cell cycle arrest and apoptosis in human hepatocellular carcinoma HepG2 cells.
We recently established that NCPMF-60, a newly synthesized flavonoid, is an active cytotoxic component. The molecular mechanisms by which NCPMF-60 exerts its cytotoxic activity are currently unknown. In this study, we show that NCPMF-60 induces G2/M phase arrest and apoptosis in human hepatocellular carcinoma HepG2 cells. After treatment of HepG2 cells with NCPMF-60, cell cycle-related proteins, such as cyclin B1, cyclin H, CDK7, and p-CDK1 (Thr161), were downregulated, whereas p21 and p-CDK1 (Thr14/Tyr15) were upregulated. The activity of CDK1/cyclinB complex was also inhibited by NCPMF-60. In addition, we observed poly(ADP-ribose) polymerase cleavage and activation of caspase 3 and caspase 9. The expression ratio of Bax/Bcl-2 was increased in the treated cells, in which Bax was also upregulated. We also found that the expression of p53 and its phosphorylation at Ser15 accumulated after the treatment of NCPMF-60. Moreover, upregulation of p21, p53-upregulated modifier of apoptosis, and Bax, three p53-target gene products, and the downregulation of Bcl-2 and MDM2, were observed in NCPMF-60-treated cells. However, p53 is not the only regulator in the stimulation of NCPMF-60 on p21 transcriptional level and posttranscriptional level. These results suggested that NCPMF-60 indeed activated the p53 pathway, which may contribute to its induction of cell cycle arrest and apoptosis in HepG2 cells. Collectively, our findings show that cell cycle arrest and apoptosis induced by NCPMF-60 was associated with the activation of p53 pathway and the inhibition of CDK-activating kinase activity in HepG2 cells.
Dai
Qin-Sheng
QS
Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, Jiangsu 2, People's Republic of China.
Liu
Wei
W
Wang
Xiao-Bing
XB
Lu
Na
N
Gong
Dan-Dan
DD
Kong
Ling-Yi
LY
Guo
Qing-Long
QL
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects*; D019926:Cyclin B / Q000037:antagonists & inhibitors / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology*; D016195:G2 Phase / Q000187:drug effects*; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D009687:Nuclear Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D019926:Cyclin B; D050759:Cyclin-Dependent Kinase Inhibitor p21; D005419:Flavonoids; D020662:Guanine Nucleotide Exchange Factors; C556271:NCPMF-60; D009687:Nuclear Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C062521:RCC1 protein, human; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D016203:CDC2 Protein Kinase