Role of Yin Yang-1 (YY1) in the transcription regulation of the multi-drug resistance () gene.

Resistance to chemotherapy hinders the successful treatment of acute lymphoblastic leukemia (ALL). The multi-drug resistance-1 (/ABCB1) gene encodes P-glycoprotein (P-gp), which plays an important role in chemoresistance; however, its transcriptional regulation remains unclear. We investigated the role of YY1 in the regulation of and its relation to ALL outcomes. Analysis of the promoter revealed four putative YY1-binding sites, which we analyzed using a reporter system and ChIP analysis. YY1 silencing resulted in the inhibition of expression and function. The clinical roles of YY1 and expression were evaluated in children with ALL. Expression of both proteins was increased in ALL patients compared to controls. We identified a positive correlation between YY1 and expression. High levels of YY1 were associated with decreased overall survival. Our results demonstrated that YY1 regulates the transcription of . Therefore, YY1 may serve as a useful prognostic and/or therapeutic target.