[Synthesized small interfering RNA inhibits the expression of DNA methyltransferase 1 in salivary adenoid cystic carcinoma].
OBJECTIVE
To select the effective siRNA which could inhibit the expression of DNA methyltransferase 1 (DNMT-1) in adenoid cystic carcinoma (ACC) and discuss the time-, and dose-dependent effect of RNA interference (RNAi).


METHODS
Four pairs of siRNA were designed, synthesized and transfected through oligofectamine reagent into ACC cell lines ACC-2, ACC-3 and ACC-M. 24, 48 and 72 h after transfection, total RNA and protein were harvested respectively. mRNA and protein expression level of DNMT-1 were detected by real time PCR, RT-PCR and Western blot, and then the effective siRNA was subsequently selected. ACC-3 as also transfected by different concentration of siRNA and the dose-dependent effect of RNAi was discussed. Cy(3) labelled GAPDH siRNA was used as a positive control.


RESULTS
Two of 4 pairs of siRNA inhibited the mRNA expression of DNMT-1 in three ACC cell lines and the expression of DNMT-1 was downregulated by 67%, 86%, 92% and 76%, 76%, 86% respectively. The gene inhibition was detected at 24 h or 48 h after transfection, maintained only 1 - 2 days and showed direct relationship to the concentration of siRNA. The change of protein expression level of DNMT-1 was consistent to the changes of mRNA.


CONCLUSIONS
The effective siRNA which could inhibited the expression of DNMT-1 of ACC were achieved. The inhibition effect of RNAi was time-dependent and dose-dependent.
Department of Oral Pathology, School of Stomatology, Shanghai Jiao Tong University, Shanghai 200011, China.
Zhen
Z
Tian
Zhi-yuan
ZY
Zhang
Dong-xia
DX
Ye
Xiao-jian
XJ
Zhou
Jiang
J
Li
D003528:Carcinoma, Adenoid Cystic / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation; D005822:Genetic Vectors; D006801:Humans; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D012468:Salivary Gland Neoplasms / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D012333:RNA, Messenger; D034741:RNA, Small Interfering; D004248:DNA (Cytosine-5-)-Methyltransferases