Panobinostat Enhances Cytarabine and Daunorubicin Sensitivities in AML Cells through Suppressing the Expression of BRCA1, CHK1, and Rad51
Figure 5
E2F1 is a critical mediator of the suppression of BRAC1, CHK1, and RAD51 by panobinostat in THP-1 cells.
THP-1 cells were treated with cytarabine or DNR alone or in combination with panobinostat for 48 h. Transcript levels for BRCA1, CHK1, RAD51, and E2F1 genes were determined by Real-time RT-PCR (Panels A&C). Whole cell lysates were subjected to Western blotting and probed with E2F1 antibody (Panel B). In vivo binding of E2F1 to the putative binding sites located in the BRCA1, CHK1, or RAD51 promoter was determined by ChIP assays with or without 10 nM panobinostat treatment for 48 h with the use of real-time PCR as described in “Material and Methods” (Panel D). THP-1 cells were infected with E2F1 or non-target control (NTC) shRNA lentivirus overnight, washed and cultured for another 72 h. shRNA knockdown of E2F1 was determined by Western blotting (Panel E) and real-time RT-PCR (Panel F). Effects of E2F1 knockdown on the transcript levels for BRCA1, CHK1, or RAD51 were determined by real-time RT-PCR (Panel F). *indicates p<0.05, **indicates p<0.005, ***indicates p<0.0005.