OBJECTIVETo investigate the effect of DNA methyltransferases 1 (DNMT-1) inhibition on the ACC-M cells in vitro and in vivo and discuss the role of DNMT-1 in the development, invasion and metastasis of salivary adenoid cystic carcinoma (SACC).

METHODSACC-M cells of stable DNMT-1 inhibition were established in a previous research. In vitro, the growth and invasion of ACC-M cells which stably inhibited DNMT-1 were detected and analyzed by methyl thiazolyl tetrazolium (MTT) growth curve, flow cytometry, plating efficiency and invasion assay. In vivo, the growth and metastasis of ACC-M cells which persistently inhibited DNMT-1 were observed and analyzed by subcutaneous injection and tail vein injection into the nude mice.

RESULTSIn vitro, the doubling time [(34.7 +/- 2.1) h], S phase fraction [(17.4 +/- 1.7)%], plating efficiency [(43.0 +/- 1.3)%] of ACC-M cells was significantly different from those of blank [(26.2 +/- 3.1) h, (31.5 +/- 2.0)%, (71.0 +/- 4.7)%], empty load control [(28.4 +/- 3.9) h, (39.0 +/- 2.0)%, (66.0 +/- 5.2)%], P < 0.05, and the invasion ability was not significantly different among these groups (P > 0.05). In vivo, the subcutaneous tumor forming rate (6/10), volume [(2.18 +/- 0.83) mm(3)], weight [(0.0156 +/- 0.0046) g] of ACC-M cells was also significantly lower than that of blank [10/10, (155.44 +/- 1.67) mm(3), (0.0724 +/- 0.0157) g], empty load control [10/10, (147.46 +/- 1.73) mm(3), (0.0729 +/- 0.0177) g], P < 0.05, but the rate of lung metastasis was not significantly different among these groups (P > 0.05), and the masses (2.0 +/- 0.5), diameter (70.0 +/- 20.3) microm of ACC-M cells was significantly lower than that of blank [(28.0 +/- 5.5), (195 +/- 25.4) microm], empty load control [(27.0 +/- 4.5), (190.0 +/- 19.9) microm], P < 0.05.

CONCLUSIONSInhibition of DNMT-1 is able to inhibit the proliferation and metastasis of ACC-M cells in vitro and in vivo.