The Discovery of a Novel Antimetastatic Bcl3 Inhibitor.

The development of antimetastatic drugs is an urgent healthcare priority for patients with cancer, because 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-κB 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 using a virtual drug design and screening approach against a computational model of the Bcl3-NF-kB1(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-NF-kB1 binding, tumor colony formation, and cancer cell migration in vitro; and tumor stasis and antimetastatic activity in vivo, while 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 intracellular targets, and confirm Bcl3 as a potential antimetastatic target.

Discovery of deshydroxy bicalutamide derivatives as androgen receptor antagonists.

Deshydroxy propioanilides were synthesised by Michael addition reaction between substituted thiophenols onto four different phenylacrylamide derivatives to give twenty-three novel deshydroxy bicalutamide derivatives lacking the central hydroxyl group. The antiproliferative activities of these compounds were evaluated against human prostate cancer cell lines and thirteen compounds showed better inhibitory activities (IC50 = 2.67-13.19 µM) compared to bicalutamide (IC50 = 20.44 µM) in LNCaP. Remarkably, novel double branched bicalutamide analogues (27 and 28) were isolated as major by-products and found to have the best activity across three human prostate cancer cell lines (LNCaP, VCaP and PC3). The most active compound 28 shows sub-micromolar activity (IC50 = 0.43 µM in LNCaP), which represents more than 40-fold improvement over the clinical anti-androgen bicalutamide (IC50 = 20.44 µM) and a more than 3 fold improvement over enzalutamide (IC50 = 1.36 µM). Moreover, strong reduction of PSA expression in LNCaP cells upon treatment with compounds 27, 28 and 33 was observed during qPCR analysis, confirming their AR antagonist activity. Molecular modelling studies revealed a novel binding mode of these structurally distinct double branched analogues within the ligand binding domain (LBD) of the androgen receptor.