Apoptotic effect of Polygonum Cuspidatum in oral cancer cells through the regulation of specificity protein 1.
OBJECTIVE
The aim of this study was to evaluate the growth inhibitory and apoptosis-inducing effects and mechanisms of Polygonum cuspidatum root in oral cancer cells.


METHODS
The testing materials were separated by normal-phase silica gel liquid chromatography. The effect of P. cuspidatum root on apoptotsis and its mechanism were performed using 3-(4,5-dimethylthiazol-20yl)-(3-carboxymethoxyphenyl)-2-(4-sulphophenyl)-2H-tetrazolium) (MTS) assay, western blot analysis, RT-PCR, promoter assay, and (4'-6-Diamidino-2-phenylindole) (DAPI) staining.


RESULTS
The methanol extract of P. cuspidatum (MEPC) inhibited the proliferation of oral cancer cells by inducing caspase-dependent apoptosis. Protein and mRNA expression levels and the transactivation of Specificity protein 1 (Sp1) were markedly decreased in KB cells treated with MEPC. Ethyl acetate fraction (EA) from MEPC was more potent than aqueous fraction (AQ) from MEPC to induce apoptosis. F2, F3, and F4 from EA differentially inhibited the growth of KB cells, and it depends on the amount of Emodin in F2, F3, and F4. Moreover, Emodin inhibited oral cancer cell growth and induced caspase-dependent apoptosis by decreasing Sp1. MEPC also decreased an apoptosis-related downstream target of Sp1 protein, survivin.


CONCLUSIONS
The results from this study strongly suggest that MEPC, its fraction, and Emodin may be potential bioactive materials to cause apoptosis mechanism via the down-regulation of Sp1 in oral cancer cells.
Shin
J-A
JA
Department of Oral Pathology, School of Dentistry and Institute of Oral Bioscience, BK21 Project, Chonbuk National University, Jeonju, Korea.
Shim
J-H
JH
Jeon
J-G
JG
Choi
K-H
KH
Choi
E-S
ES
Cho
N-P
NP
Cho
S-D
SD
D000085:Acetates; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000187:drug effects; D015153:Blotting, Western; D020169:Caspases / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004642:Emodin / Q000494:pharmacology; D045468:Fallopia japonica; D005456:Fluorescent Dyes; D006801:Humans; D007211:Indoles; D051034:Inhibitor of Apoptosis Proteins / Q000187:drug effects; D007624:KB Cells / Q000187:drug effects; D000432:Methanol; D009062:Mouth Neoplasms / Q000473:pathology*; D010936:Plant Extracts / Q000494:pharmacology*; D018517:Plant Roots; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012997:Solvents; D016329:Sp1 Transcription Factor / Q000187:drug effects*; D000077022:Survivin; D013778:Tetrazolium Salts; D013844:Thiazoles
D000085:Acetates; D051017:Apoptosis Regulatory Proteins; C107489:BIRC5 protein, human; D004396:Coloring Agents; D005456:Fluorescent Dyes; D007211:Indoles; D051034:Inhibitor of Apoptosis Proteins; D010936:Plant Extracts; D047428:Protein Kinase Inhibitors; D012997:Solvents; D016329:Sp1 Transcription Factor; D000077022:Survivin; D013778:Tetrazolium Salts; D013844:Thiazoles; C070380:3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium; C007293:DAPI; C007650:ethyl acetate; D020169:Caspases; D004642:Emodin; D000432:Methanol