Cell permeable, potent and selective class IIb HDAC6 inhibitor (IC50=3nM). Displays high selectivity over HDAC1 (300-fold). More soluble analog of nexturastat A (Prod. No. AG-CR1-3901). Suppresses cell proliferation of B16 cells (GI50=14.3µM) and human lymphoma cells HuT-78 at a slightly lower concentration than nexturastat A. Shown to be effective in a mouse melanoma tumor xenograft model, increasing tumor volumes in vivo. Down-regulates the production of IL-10. HDAC6 deacetylates tubulin, HSP90 and the core histones (H2A, H2B, H3, H4). Histone deacetylases act via the formation of large multiprotein complexes. HDAC6 plays an important role in microtubule-dependent cell motility, transcriptional regulation, degradation of misfolded proteins and cell cycle and is involved in autophagy, inflammation, cancer and neurodegeneration.