Abstract P2-06-04: p300 acts as a tumor suppressor by inhibiting pro-metastatic microRNA pathways

The histone acetyltransferase p300 is an important epigenetic factor known to regulate gene silencing, DNA repair, and cell cycle. Altered p300 expression is linked to cancerous phenotypes and has potential as both a biomarker and therapeutic target. Existing anti-cancer therapies such as histone deacetylase inhibitors (vorinostat, valproic acid, trichostatin A) are known to affect p300 levels and activity. Understanding how p300 affects cancerous and metastatic development is crucial to optimizing and advancing these treatments. However, whether p300 acts as a tumor suppressor or promoter is still controversial. To address this issue, we stably knocked down p300 levels in MCF-7, BT 474 and MDA MB 231 to 30-40% endogenous levels to directly examine p3009s effects on tumorigenicity. Our experiments show loss of p300 significantly increased cell motility in the scratch assay (p To identify targets of p300 that might regulate its anti-tumor effect, we observed that miR-let-7c was downregulated in KD-p300 MCF-7 by 70% (p Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-06-04.