ML 120B is a novel competitive inhibitor of ATP and i-kappa-kinase-2 (IKK2), key regulator in the survival, proliferation and apoptosis resistance of lymphoma cells.
mln120b is a potent and effective inhibitor of iκb kinase beta subunit (ikkβ) with ic50 value of 20 μm [1].ikk is an enzyme complex which is a part of the upstream of nf-κb signal transduction cascade. it is composed of three subunits, including ikkα, ikkβ and ikkγ. the ikkβ subunit is able to phosphorylate iκbα protein. normally, iκbα protein inactivate nf-κb transcription factors and keep them sequestering in inactive state in the cytoplasm. however, once iκbα protein is phosphorylated by ikkβ subunit, the iκbα protein will be dissociated from nf-κb transcription factor and thus remove the inactivation effect. therefore, the transcription of nf-κb will be activated. this signaling pathway is involved in many immune and inflammatory processes.in multiple myeloma cell line rpmi 8226 and ina 6, treatment of mln120b resulted in the dose-dependent inhibition of ikkβ-induced iκbα protein phosphorylation and subsequent nf-κb activation. additionally, it was observed that mln120b was able to block tnf-α-induced nf-κb activation in mm.1s cell line. these observations suggested the inhibitory action of mln120b on ikkβ. [1].in mouse model, polyarthritis was introduced in footpads, where ikkβ-induced nf-κb activation might result in a serial of advert effects. oral administration of mln120b (12 mg/kg twice daily) inhibited paw swelling in a dose-dependent manner, and offered protection against arthritis-induced weight loss. therefore, it could be implied that mln120b was able to inhibit ikkβ-induced nf-κb activation [2].
[1]. hideshima t, neri p, tassone p. mln120b, a novel ikappab kinase beta inhibitor, blocks multiple myeloma cell growth in vitro and in vivo. clin cancer res. 2006, 12(19): 5887-5894.
[2]. schopf l, savinainen a, anderson k. ikkbeta inhibition protects against bone and cartilage destruction in a rat model of rheumatoid arthritis. arthritis rheum. 2006, 54(10): 3163-3173.
