A natural compound derivative P-13 inhibits STAT3 signaling by covalently inhibiting Janus kinase 2

SummaryWe investigated the function and molecular mechanisms of 2-desoxy-4 β-propylcarbamate-pulchellin (P-13), a sesquiterpene lactone derivative of 2-desoxy-4-epi-pulchellin from the traditional Chinese medicinal herb Carpesium abrotanoides L, in regulating STAT3 signaling and cancer cell growth. We found that P-13 inhibited the IL-6-induced, as well as the constitutive , STAT3 activation in a dose and time-dependent manner. In vitro kinase activity analyses demonstrated that P-13 directly inhibited JAK2 kinase activity. The inhibitory effects of P-13 on JAK2/STAT3 signaling could be blocked by reducing agents dithiothreitol (DTT) or glutathione (GSH), indicating a n involvement of the thiol-reactive α-β unsaturated carbonyl group in P-13. Further analyses with mass spectrograph, as well as molecular docking, revealed that P-13 covalently bound with the C452 in the SH2 domain of JAK2. Furthermore, P-13 inhibited growth and induced death of many cancer cell l ines, particularly those expressing constitutively activated STAT3. It also inhibitedin vivo growth of human cancer cell xenografts. Taken together, these findings revealed P-13 as a novel covalent inhibitor of JAK2, uncovered a new mechanism to inhibit JAK2, and provided a promising anti-cancer drug candidate.
Source: Investigational New Drugs - Category: Drugs & Pharmacology Source Type: research