LY2409881 (trihydrochloride)

LY2409881 trihydrochloride is a selective IκB kinase β (IKK2) inhibitor with an IC₅₀ of 30 nM. IC50 & Target: IC50: 30 nM (IKK2)^[1] In Vitro: LY2409881 is an IKK2 inhibitor that inhibits TNFα-induced activation of NF-κB. By in vitro kinase assay, LY2409881 potently inhibits IKK2, with an IC₅₀ of 30 nM. In contrast, the IC₅₀ for IKK1 and other common kinases is at least one log higher. The specificity of LY2409881 for NF-κB signaling is further studied in a cell-based assay, by examining the effect of LY2409881 in the TNFα-dependent antiapoptosis function. TNFα is a well-characterized upstream stimulus of NF-κB. In the ovarian cancer cell line SKOV3, LY2409881 demonstrates moderate cytotoxicity, whereas TNFα at 10 ng/mL does not cause any cytotoxicity. In contrast, coadministration of LY2409881 and TNFα results in markedly higher cell killing compared with LY2409881. This is because TNFα-dependent activation of antiapoptotic signals mediated by NF-κB is blocked by LY2409881, while the proapoptotic TNF receptor-associated death domain (TRADD) and FAS-associated death domain (FADD) cascade pathways activated by TNFα are not affected by LY2409881^[1]. In Vivo: A well-established xenograft model of DLBCL is used to confirm the activity of LY2409881 in vivo. SCID-beige mice implanted with LY10 cell-derived tumors are given intraperitoneal injections of LY2409881 twice weekly at three different doses: 50, 100, and 200 mg/kg. The treatments are well tolerated, resulting in no death or severe morbidity of the mice. The average tumor volume is graphed as a function of time for each treatment group. The rates of tumor volume growth of the treatment groups are all significantly slower than the untreated control group (P≤0.01)^[1].