[Growth inhibition and demethylation by a component of natural drug, CDP, in cancer cell lines].
OBJECTIVE
To investigate the inhibition of tumor cell lines' growth and the demethylation of p16 gene by a component of natural drug, CDP.


METHODS
Human liver cancer cell line Huh-7 and breast cancer cell line T47D were treated with the CDP and DNA methyltransferase inhibitor, 5-azacytidine (5-aza-C). The inhibition of growth was assayed by MTT; the methylation status of p16 gene promoter was analyzed by MSP.


RESULTS
1. The CpG islands in promoter of p16 gene were identified as completely methylated in Huh-7 and T47D. 2. CDP and 5-aza-C inhibited the proliferation of Huh-7 and T47D cell lines in a dose, time-dependent mode. 3. Methylation-specific bands of CpG islands in p16 gene' promoter were still existed in Huh-7 and T47D, while unmethylation-specific bands appeared in Huh-7 after the cells being treated with 25, 50, 75 and 100 micromol/ L of CDP for 6 days as well as in T47D after the cells being treated with 50, 75 and 100 micromol/L of CDP for 6 days. 4. After the cells being treated with 50 micromol/L of CDP, the methylation-specific bands of CpG island in p16 gene' promoter were still existed in Huh-7 and T47D; unmethylation-specific bands appeared at 12 h and lasted to 144 h in Huh-7 while at 72 h and lasted to 144 h in T47D.


CONCLUSIONS
CDP has inhibition effect on the cancer cell lines and has the ability to reverse the hypermethylated p16 gene promoter. These results suggest that CDP has great potential in the development of effective anticancer drugs.
Luan
Ju
J
Department of Biochemistry and Molecular Biology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
Qin
Yang
Y
Xu
Dan
D
Sun
Zhi-Lin
ZL
Sun
Ze-Fang
ZF
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D045744:Cell Line, Tumor; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation / Q000187:drug effects*; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D020868:Gene Silencing / Q000187:drug effects*; D019942:Genes, p16; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000473:pathology*; D011401:Promoter Regions, Genetic / Q000187:drug effects
D000972:Antineoplastic Agents, Phytogenic; D004365:Drugs, Chinese Herbal