5-Azacytidine treatment induces demethylation of and genes and inhibits growth in canine mammary gland tumor cells.

Background: Canine mammary gland tumors (CMGTs) are the most common, spontaneous types of neoplasias in female dogs. Aberrant and methylation associated with tumor formation and development in various cancers. 5-Azacytidine is a known specific demethylation drug that covalently binds to DNA methyltransferase. However, the methylation of the and is unknown with respect to CMGTs. Therefore, we sought to demonstrate the effects of 5-azacytidine on the proliferation of CMGTs cell, and elucidate the potential molecular mechanisms of action in these cancerous cells.

Materials And Methods: The effects of 5-azacytidine on CHMm and CHMp cell proliferation were evaluated by MTT assay. The and gene methylation patterns in CHMm and CHMp cells and CMGTs blood/tissue samples were analyzed by MSP assay. Effect of 5-azacytidine on the methylation of and gene, and and mRNA expression in CHMm and CHMp cells were analyzed by MSP assay and qRT-PCR assay, respectively.

Results: 5-Azacytidine may suppress the proliferation of CHMm and CHMp cells. Furthermore, the and genes were hypermethylated in CHMm/CHMp cells and clinical malignant tumor samples, but not in normal female dogs' blood and tissue. However, the and genes were re-inducible in CHMm and CHMp cells treated with 5 μM 5-azacytidine. Meanwhile, 5-azacytidine increased the expression of and mRNA.

Conclusion: These results suggest that and methylation can serve as sensitive diagnostic biomarkers and therapeutic targets for CMGTs. 5-Azacytidine also could be a potential therapeutic candidate for CMGTs.