title: A phenylacetate derivative, SCK6, inhibits cell proliferation via G1 cell cycle arrest and apoptosis.
abstract: Phenylacetate is a differentiation agent and has anticancer activity with relatively low toxicity. In the present study, we examined the anticancer effect of six synthetic phenylacetate derivatives in human lung cancer cells in our search for more effective phenylacetate analogous. Results showed that the antiproliferative effects of these synthetic compounds were stronger than those of phenylacetate, and that N-butyl-2-(2-fluorolphenyl)acetamide (SCK6) is the most potent compound. To address the mechanism of the antiproliferative effect of SCK6, cell cycle analysis was performed. Result showed that SCK6 (1 mM) induced G(1) arrest in CH27 cells. Western blot analysis of G(1) phase regulatory proteins demonstrated that the protein levels of cyclin-dependent kinase 2 (Cdk2), Cdk4, Cyclin E and Cyclin D3 were decreased after treatment with SCK6 but not those of Cdk6, Cyclin D1 and D2. In contrast, SCK6 increased the protein levels of p53 and p21(CIP1/WAF1). Data from in situ terminal transferase-mediated dUTP-fluorescensin nick end-labeling (TUNEL) assay and DNA fragmentation analysis demonstrated that SCK6 induced apoptotic cell death in CH27 cells. This SCK6-induced apoptosis was accompanied by a downregulation of Bcl-2 protein and activation of the caspase-9 cascade. Overexpression of Bcl-2 by adeno-Bcl-2 vector infection significantly inhibited SCK6-induced apoptosis. Moreover, treatment with caspase inhibitors also markedly reduced cell death induced by SCK6. Taken together, these results suggest that downregulation of G(1)-associated Cdks and cyclins and upregulation of p53 and p21(CIP1/WAF1) may contribute to SCK6-mediated G(1)-phase arrest. Furthermore, the decrease in Bcl-2 and the activation of caspase-9/caspase-3 may be the effector mechanism through which SCK6 induces apoptosis.
authors.affiliation: Department of Biochemistry, China Medical College, Taichung, Taiwan, ROC.
authors.forename: Hsu-Chin
authors.initials: HC
authors.lastname: Chan
authors.forename: Sheng-Chu
authors.initials: SC
authors.lastname: Kuo
authors.forename: Li-Jiau
authors.initials: LJ
authors.lastname: Huang
authors.forename: Chung-Hsien
authors.initials: CH
authors.lastname: Liu
authors.forename: Shih-Lan
authors.initials: SL
authors.lastname: Hsu
mesh_terms: D000081:Acetamides / Q000494:pharmacology*; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D042846:CDC2-CDC28 Kinases / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D016213:Cyclins / Q000037:antagonists & inhibitors / Q000378:metabolism; D045304:Cytochromes c / Q000096:biosynthesis; D004789:Enzyme Activation; D016193:G1 Phase / Q000187:drug effects*; D005786:Gene Expression Regulation; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: C470118:4-fluoro-N-butylphenylacetamide; D000081:Acetamides; D000964:Antimetabolites, Antineoplastic; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D045304:Cytochromes c; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495900:CDK4 protein, human; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases