HDAC8 and STAT3 repress BMF gene activity in colon cancer cells.

Cell death & disease (2014-10-17)
Y Kang, H Nian, P Rajendran, E Kim, W M Dashwood, J T Pinto, L A Boardman, S N Thibodeau, P J Limburg, C V Löhr, W H Bisson, D E Williams, E Ho, R H Dashwood
ABSTRACT

Histone deacetylase (HDAC) inhibitors are undergoing clinical trials as anticancer agents, but some exhibit resistance mechanisms linked to anti-apoptotic Bcl-2 functions, such as BH3-only protein silencing. HDAC inhibitors that reactivate BH3-only family members might offer an improved therapeutic approach. We show here that a novel seleno-α-keto acid triggers global histone acetylation in human colon cancer cells and activates apoptosis in a p21-independent manner. Profiling of multiple survival factors identified a critical role for the BH3-only member Bcl-2-modifying factor (Bmf). On the corresponding BMF gene promoter, loss of HDAC8 was associated with signal transducer and activator of transcription 3 (STAT3)/specificity protein 3 (Sp3) transcription factor exchange and recruitment of p300. Treatment with a p300 inhibitor or transient overexpression of exogenous HDAC8 interfered with BMF induction, whereas RNAi-mediated silencing of STAT3 activated the target gene. This is the first report to identify a direct target gene of HDAC8 repression, namely, BMF. Interestingly, the repressive role of HDAC8 could be uncoupled from HDAC1 to trigger Bmf-mediated apoptosis. These findings have implications for the development of HDAC8-selective inhibitors as therapeutic agents, beyond the reported involvement of HDAC8 in childhood malignancy.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
C646, ≥98% (HPLC)
Sigma-Aldrich
MISSION® esiRNA, targeting human BMF
Sigma-Aldrich
MISSION® esiRNA, targeting mouse Bmf