14003-96-4

4μ8C (14003-96-4) is a selective inhibitor of IRE1α ribonuclease (RNase) activity (IC50?= 60 nM). Covalently binds to lysine 907 in the IRE1 endonuclease domain, blocking substrate access to the active site of IRE1α and inactivating both XBP1 splicing and IRE1α-mediated mRNA degradation but not IRE1 kinase activity.1?Inhibits IRE1α in response to hypoxia or other ER stress-inducing agents but has no effect on proliferation or clonogenic survival of hypoxic cells.2?Blocks production of IL-4, IL-5 and IL-13 production in T cells.3?4μ8C prevents the splicing of the XBP1 mRNA in response to ER stress caused by mutant proinsulin production in pancreatic β-cells.4

8-Formyl-4-methylumbelliferone is an inhibitor that blocks substrate access to the active site of IRE1 and selectively inactivates both Xbp1 splicing and IRE1-mediated mRNA degradation.

Cell permeable: yes

The general procedure for the synthesis of 7-hydroxy-4-methyl-2-oxo-2H-benzopyran-8-aldehyde from hydroxymethylcoumarin and orotropin was as follows: 8-formyl-7-hydroxy-4-methylcoumarin was prepared with reference to the literature method. 7-Hydroxy-4-methylcoumarin (10 g, 56.8 mmol) was dissolved in glacial acetic acid (90 mL) with hexamethylenetetetramine (19.9 g, 142 mmol) and the reaction was heated for 6 hours at 70-80 °C. After the reaction was completed, 20% hydrochloric acid (130 mL) was added to the mixture and heating was continued for 40 minutes. The reaction solution was cooled to room temperature and extracted twice with ether. The organic layers were combined and concentrated under reduced pressure to give the target compound as a light yellow powder. The crude product was purified by recrystallization from methanol in 45% yield. Melting point: 140-142 °C. 1H NMR (300 MHz, CDCl3) δ: 12.24 (s, 1H), 10.64 (s, 1H), 7.76-7.73 (d, 1H), 6.94-6.91 (d, 1H), 6.23 (s, 1H), 2.45 (s, 3H). ft-ir (KBr, cm-1 ): 3050, 1720, 1610.

Store at -20°C

1) Cross?et al. (2012),?The molecular basis for selective inhibition of unconventional mRNA splicing by an IRE1-binding small molecule; Proc. Natl. Acad. Sci. USA,?109?E869 2) Cojocari?et al. (2013),?New small molecule inhibitors of UPR activation demonstrate that PERK, but not IRE1α signaling is essential for promoting adaptation and survival to hypoxia;? Radiother. Oncol.,?108?541 3) Kemp?et al. (2013),?The serine-threonine kinase inositol-requiring enzyme 1α (IRE1α) promotes IL-4 production in T helper cells; J. Biol. Chem.,?288?33272 4) Zhang?et al. (2014),?IRE1 inhibition perturbs the unfolded protein response in a pancreatic β-cell line expressing mutant proinsulin, but does not sensitize the cells to apoptosis;? BMC Cell Biol.,?15?29