The RING finger-dependent ubiquitin ligase (E3) gp78, known as the tumor autocrine motility factor receptor, contributes to tumor progression. The protein interacts with its cognate ubiquitin-conjugating enzyme (E2), Ube2g2, via its RING domain and a unique region called G2BR that strongly binds to the E2. The binding of G2BR to Ube2g2 allosterically enhances the binding of RING to the E2, and the binding of RING triggers the departure of G2BR from the E2 also in an allosteric fashion. Targeting these allosteric events, we developed a family of inhibitors that irreversibly block E2-E3 interactions and thereby eliminate the tumorigenic effect of gp78. One among 19 compounds screened with the NCI 60 tumor cell lines exhibited outstanding anticancer activities. At 10 mM, it caused > 50% growth inhibition to 40% cell lines; at 100 mM, it showed lethiferous activity against most cell lines.
Design, synthesis, and anticancer activity evaluation of irreversible allosteric inhibitors of ubiquitin-conjugating enzyme Ube2g2