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Interleukin 1 (IL-1) receptor-associated kinases (IRAKs) are serine/threonine kinases that play critical roles in initiating the innate immune response against foreign pathogens. Additionally, dysregulation of IRAK1 signaling plays a role in neoplastic disorders. For example, IRAK1 was shown to be important for survival and proliferation in many B-cell lymphomas, including Waldenström's macroglobulinemia (WM) and ABC subtype Diffused Large B-cell Lymphoma (DLBCL) cells. Here, we report the discovery of a highly potent and selective covalent inhibitor of IRAK1, JH-X-119-01. Intact protein MS labeling studies confirmed that JH-X-119-01 irreversibly labels IRAK1 at C302. This compound exhibited cytotoxic activity at single digit micromolar concentrations in a panel of WM, DLBCL, and lymphoma cell lines expressing MYD88. Cotreatment of JH-X-119-01 with the BTK inhibitor ibrutinib resulted in synergistic killing effects in these systems. Taken together, JH-X-119-01 represents a highly selective probe of IRAK1 for further development., Competing Interests: The authors declare the following competing financial interest(s): N.S.G. is a founder, science advisory board member (SAB), and equity holder in Gatekeeper, Syros, Petra, C4, B2S, Aduro, Inception, Allorion, Jengu and Soltego (board member). The Gray lab receives or has received research funding from Novartis, Takeda, Astellas, Taiho, Janssen, Kinogen, Voronoi, Her2llc, Deerfield, and Sanofi. S.P.T. lab receives or has received funding from Pharmacyclics/Abbvie, Janssen Pharmaceuticals, Beigene, and Bristol Myers Squibb. J.A.M. serves on the SAB of 908 Devices. The Marto lab receives sponsored research support from Vertex and Astra-Zeneca. S.B. is a scientific advisory board member of Adenoid Cystic Carcinoma Foundation. H.W. is a co-founder, SAB member, and equity holder of Ventus Therapeutics., (© 2020 American Chemical Society.)

Macrocyclic Hedgehog (Hh) pathway inhibitors have been discovered with improved potency and maximal inhibition relative to the previously reported macrocycle robotnikinin. Analogues were prepared using a modular and efficient build-couple-pair (BCP) approach, with a ring-closing metathesis step to form the macrocyclic ring. Varying the position of the macrocycle nitrogen and oxygen atoms provided inhibitors with improved activity in cellular assays; the most potent analogue was 29 (BRD-6851), with an IC(50) of 0.4 μM against C3H10T1/2 cells undergoing Hh-induced activation, as measured by Gli1 transcription and alkaline phosphatase induction. Studies with Patched knockout (Ptch(-/-)) cells and competition studies with the Smoothened (Smo) agonists SAG and purmorphamine demonstrate that in contrast to robotnikinin, select analogues are Smo antagonists.