[SHP-1 gene's methylation status of Daudi lymphoma cell and the demethylation effect of 5-aza-2'-deoxycytidine].

Objective To explore the transcription regulation of 5-aza-2'-deoxycytidine(5-Aza-CdR) on SHP-1 gene and its effects on Daudi cell line growth.Methods MTF method and flow cytometrv were used to detect the glowth and apoptosis of Daudi cells after treated with different dosage of 5-Aza-CdR.Bisul- fite sequencing PCR(BSP),T-A cloning and sequence analysis were evaluated for methvlation status.The SHP-1 mRNA and protein were determined by reverse transeription polymerase chain reaction (RT-PCR) ,im- munohistochemistry.Results①After 7 d trealment with 2.00 μmol/L of 5-Aza-CdR,all cytosines (C)in Daudi cells genone DNA were converted to,thymidine,and SHP-1 mRNA and protein expressed again in the cells while those Cs in CpG dinucleotides in untreated Daudi ceils remained Cs:②5-Aza-CdR inhibited the cell growth,The effects within certain extent were dose and time dependent:afler 72 h treatrent with 5-Aza- CdR at 200.00.20.00,2.00 and 0.20 μmol/L,the inhibitive rates were 72.0% ,65.1%,51.5%, 28.8% ,23.4% respectively;③5-Aza-CdR increased apoptosis rate of tumor cells with a dose and times de- pendent manner within certain extent,too:at the 1,3,5 d treatment with 5-Aza-CdR 2.00 μmol/L,the apopto- sis rates were 2.3% ,10.8% and 17.1% ;respectively.④5-Aza-CdR also ehanged cell cyele of tumor cells : at 24 h treatmant with 5-Aza-CdR 2.00 μmoL/L,92.7% tumor cells stopped at S phase and G_1 phase cells were increased gradually with time.Conclusion DNA promoter hypermethylation is asseioated with SliP-1 gene silence in Daudi lymphoma cell line.5-Aza-CdR could effectively cause demethylation and inhibit the growth of tumor cell by reactivating the gene transcription.