Trichostatin A sensitivity signature across hematological cell lines.

Abstract

e19521 Background: Histone deacetylase inhibitors (HDACi) are small molecules that increase acetylation of lysine residues by blocking histone deactylases. These anticancer agents affect epigenetic and non-epigenetic gene expression resulting in cell cycle arrest of cancer cells. Furthermore HDACi can enhance its anti-tumor effects via the pharmacologic modulation of macrophage. Some HDACi’s such as Trichostatin A (TSA) can also affected the tumor immune microenvironment by suppressing the activity of infiltrating macrophages and inhibiting myeloid-derived suppressor cell recruiement (Li et al.,). Methods: We conducted a high throughput screen comparing gene expression profiles in known hematological cell lines to identify transcriptional signatures associated with TSA sensitivity obtained from GDSC. Results: We selected genes that showed at least 2fold expression difference and were statistically significant (p < 0.05). We identified 49 genes that were upregulated and 85 that were downregulated. The most significant results include multiple genes known to be correlated with the B-cell maturation process. We found that CD24 a small GPI linked glycoprotein expressed at the surface of most B lymphocyte precursors, neutrophils, epithelial cells and frequently found to be highly expressed in various hematological and solid neoplasms, was up/downregulatred by XX. Interestingly, CD24 plays a role in the activation and differentiation of the cells as bone marrow samples lacking CD24 resulted in decreased numbers of both pre-B and immature B-cell populations. We also found that IKZF2, a transcription factor regulating lymphocyte development and queiesence and which is frequently deleted in hypodiploid B-ALLs. This result could revelent as other reports suggest a role of IKZF2 as a tumor suppressor with a central role regulating the balance of self-renewal and differentiation in leukemic stem cells. Conclusions: Our study identified transcriptional profiles which suggest that TSA sensitivity could be related to B cell maturation. Further experiments warrant replication of these findings which could prove useful in creating optimal, TSA-based treatments acting either as potent single agents or in combination enhancing anti-tumor effects of immunotherapies.