mrna cleavage

Toyocamycin (Vengicide) is an adenosine analog produced by Actinomycetes, functioning as an XBP1 inhibitor and inhibiting IRE1α-induced ATP-dependent XBP1 mRNA cleavage (IC50: 80 nM), and induces apoptosis.

AK177 is an allosteric activator of IRE1α ribonuclease, exhibiting binding affinities of 480 nM for non-phosphorylated and 180 nM for phosphorylated IRE1α. It promotes concentration-dependent cleavage of XBP1 mRNA probes by IRE1α and stably binds its kinase domain. However, AK177 displays poor kinase selectivity, and due to inadequate membrane permeability, shows negligible downstream pathway activation and antiproliferative activity at the cellular level.

Cortistatin-29 is a neuropeptide that is structurally similar to somatostatin-28. It is produced by cleavage of preprocortistatin to procortistatin, which is cleaved at dibasic amino acids to form cortistatin-29 and cortistatin-14 as well as other partial cleavage products. Cortistatin mRNA is expressed in the human brain and in interneurons of the rat hippocampus and cerebral cortex. Cortistatin-29 binds to somatostatin (SST) receptors with IC50 values of 2.8, 7.1, 0.2, 3, and 13.7 nM for SST1-5, respectively. Cortistatin-29 is found at similar levels as cortistatin-14 in mouse AtT20 cells but is secreted at a lower level. Cortistatin-29 corresponds to residues 85-112 of the rat peptide sequence.

AZ5576 racemate is a racemic mixture of AZ5576 isomers. AZ5576 is a potent, highly selective, and orally bioavailable inhibitor of Cdk9 that inhibits Cdk9 enzyme activity with an IC50 <5nM and decreases phosphorlyation of Ser2-RNAPII in cells with an IC50 of 96nM. In the MLL-fusion containing acute myeloid leukemia (AML) line, MV411, short-term treatment with AZ5576 led to a rapid dose-dependent decrease in pSer2-RNAPII with concomitant loss of Mcl1 mRNA and protein, resulting in the cleavage and activation of caspase 3 and loss of cell viability.