Chromatin Reader ZMYND8 is a Key Target of All Trans Retinoic Acid-mediated Inhibition of Cancer Cell Proliferation

All trans retinoic acid (ATRA), an active vitamin-A derivative, has been shown to regulate gene expression program and thus imparts anti-proliferative activity to cancer cells. Previously, we identified a dual histone reader ZMYND8 (zinc finger MYND (Myeloid, Nervy and DEAF-1)-type containing 8), to be a novel target of ATRA. In the present study, we attempted to decipher the detail mechanism of its transcription regulation. ATRA can reprogram the epigenetic landscape in the upstream regulatory region of ZMYND8 thereby promoting its expression. Interestingly, there is a unique H3K27Me3 to H3K27Ac switch upon ATRA-treatment. We show here that ATRA causes dynamic changes in recruitment of transcription factor YY1 in concert with HDAC1 at ZMYND8 promoter. Further, we show that ATRA treatment triggers an anti-proliferative activity in cancer cells through regulation of ZMYND8 expression. Subsequently, in 4T1-induced syngenic tumor mouse model, ATRA injection caused significant upregulation of ZMYND8. Overall our findings highlight a novel mechanism underlying ATRA-mediated changes in ZMYND8 expression which, in turn, activates the anti-proliferative program in a cancer cell. Thus, histone reader mediated modulation of epigenetic language could play a significant role in retinoid based therapeutic strategy which is well exploited to combat tumor growth.