The development of anti-metastatic drugs is an urgent healthcare priority for cancer patients, since metastasis is thought to account for around 90% of cancer deaths. Current antimetastatic treatment options are limited and often associated with poor long-term survival and systemic toxicities. Bcl3, a facilitator protein of the NF-B family, is associated with poor prognosis in a range of tumor types. Bcl3 has been directly implicated in the metastasis of tumor cells, yet is well tolerated when constitutively deleted in murine models, making it a promising therapeutic target. Here we describe the identification and characterization of the first small molecule Bcl3 inhibitor, by employing a virtual drug design and screening approach against a computational model of the Bcl3-NFkB1(p50) protein-protein interaction. From selected virtual screening hits, one compound (JS6) showed potent intracellular Bcl3-inhibitory activity. JS6 treatment led to reductions in Bcl3-NFkB1 binding, tumor colony formation and cancer cell migration in vitro; and tumor-stasis and anti-metastatic activity in vivo, whilst being devoid of overt systemic toxicity. These results represent a successful application of in silico screening in the identification of protein-protein inhibitors for novel intra-cellular targets, and confirm Bcl3 as a potential anti-metastatic target.

Highlights  Synthesis of 23 novel deshydroxy bicalutamide derivatives.  Identification of novel and potent double branched AR antagonists.  Enhanced anticancer activity against PC compared to bicalutamide and enzalutamide.  Strong downregulation of PSA expression in qPCR analysis of LnCaP cell line.  Molecular modelling provides a rational explanation of the SAR observed.