[Effect of spleen tyrosine kinase expression re-activation by inhibition of DNA methylation on oncogenesis growth of gastric cancer].
OBJECTIVE
To explore the effects of 5-Aza-2'-deoxycytidine on spleen tyrosine kinase (Syk) expression by inhibition of DNA methylation and the effect of re-activation of Syk on oncogenesis of gastric cancer.


METHODS
Syk mRNA of SGC7901, MGC803, MKN28 and MKN45 cell lines were analyzed by RT-PCR, and Syk methylation were detected by MSP. 5-aza-CDR was used to incubate with human gastric cancer cell line SGC7901, Methylation of Syk promoter region was detected by MSP and RT-PCR technique was used to detected Syk gene in the methylated and silenced Syk gene in the cell line SGC7901. Meanwhile, cell lines were inoculated into subcutaneous tissue of nude mice.


RESULTS
No Syk mRNA were found in SGC7901 and MKN45 gastric cancer cell lines, but methylation of Syk were detected in those cell lines. No methylation of Syk promoter region was found and Syk gene was detected in the Syk-negative cell line SGC7901 after incubated with 5-aza-CDR. Of 10 nude mice which were inoculated SGC7901(Syk(+)), 3 were observed macroscopic tumor 8 weeks after the injection. On contrast, tumors were found in 10 nude mice which were inoculated SGC7901 (Syk(-)) 8 weeks after the injection, a significant difference was noted between the two groups (chi (2)=7.91, P<0.05).


CONCLUSIONS
Syk gene is re-expressed in the cell line SGC7901 by demethylation with 5-aza-CDR. Syk gene re-expression suppress the malignant oncogenesis and growth of human gastric cancer.
Ding
Yong-bin
YB
Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
Xia
Jian-guo
JG
Chen
Guo-yu
GY
D000818:Animals; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D045744:Cell Line, Tumor; D018899:CpG Islands; D019175:DNA Methylation; D000077209:Decitabine; D005260:Female; D015870:Gene Expression; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D011401:Promoter Regions, Genetic; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology*; D000072377:Syk Kinase
D047908:Intracellular Signaling Peptides and Proteins; D000077209:Decitabine; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; C000606897:Syk protein, mouse; D001374:Azacitidine