[In vitro study about the inhibitory effect of CDAII in combination with sodium butyrate on breast cancer cells].
OBJECTIVE
To investigate if the combined use of CDAII and sodium butyrate can induce demethylation and re-expression of retinoic acid receptor beta2 (RARbeta2) gene in cultured human breast cancer cells MCF7. To explore if the two drugs can inhibit cell growth and induce cell apoptosis synergetically.


METHODS
MCF7 cell line was treated with CDAII, sodium butyrate, combination of the two drugs respectively. Methylation was assessed by methylation-specific polymerase chain reaction (MSP) for RARbeta2 gene. Gene expression was evaluated by reverse transcription polymerase chain reaction (RT-PCR). Apoptosis was detected by terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling(TUNEL) and Hoechst33342/propidiumiodide (PI) staining. Cell growth inhibition was measured by MTT assay.


RESULTS
Neither CDAII nor sodium butyrate induced demethylation and re-expression of RARbeta2 gene, Combination of the two drugs partially demethylated gene promoter accompanied by re-expression of RARbeta2. The apoptotic cells in the double-drug group were obvious following Hoechst33342/PI staining. The percentage of apoptotic cells in the double-drug group was significantly higher than that of the two single-drug group (39.5% vs 5.2%, 8.1%) (P<0.05). MTT assay showed that compared with single drug,combination of the two drugs inhibited cell growth more significantly, and the two drugs showed interaction (F=15, P<0.05).


CONCLUSIONS
We showed that CDAII, in combination with histone deacetylase inhibitor sodium butyrate synergetically inhibited the proliferation of MCF7 breast cancer cell line and induced apoptosis, in which demethylation and re-expression of RARbeta2 gene induced by combination of the two drugs may be involved.
Zhu
Yan
Y
Department of Oncology, Peking University First Hospital, Beijing 100034, China.
Zhao
Yu-liang
YL
Bu
Ding-fang
DF
Shi
Yong-jin
YJ
D017209:Apoptosis / Q000187:drug effects*; D020148:Butyric Acid / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects*; D019175:DNA Methylation; D004357:Drug Synergism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006801:Humans; D061986:MCF-7 Cells; D018168:Receptors, Retinoic Acid / Q000378:metabolism*
D056572:Histone Deacetylase Inhibitors; C533416:RARB2 protein, human; D018168:Receptors, Retinoic Acid; D020148:Butyric Acid