Mayo Clinic Comprehensive Cancer Center (Minnesota)

Prostate cancer is the most common cancer in two thirds of the world, with an expected doubling in both incidence and mortality in the next two decades. No strong environmental associations exist for the development of prostate cancer; therefore, lifestyle measures are unlikely to mitigate this increasing burden. The last three decades have seen rapid developments in the diagnostic and therapeutic landscape of prostate cancer, including multiparametric magnetic resonance imaging, positron emission tomography, robotic surgery, image-guided hypofractionated and stereotactic radiotherapy, novel anti-androgens and radioligand therapies. Prostate cancer is unique in that not everyone with a diagnosis needs treatment, and active surveillance is the preferred option for some. This review discusses the contemporary management of all stages of prostate cancer in the light of these modern developments, enabling holistic individualization of treatment, and describes the promise of future research to further improve outcomes.

BET bromodomain inhibitors demonstrate significant promise as anti-inflammatory agents targeting a variety of inflammatory disorders. However, clinical data has demonstrated that the administration of non-selective BET bromodomain inhibitors has led to significant dose-limiting toxicity in clinical settings. More selective inhibitors of the second BET bromodomains, referred to as pan-D2 inhibitors, are better tolerated, however their efficacy varies significantly depending on disease indication. Here, we use three orally bioavailable inhibitors, 1–3, that are either selective for the first N-terminal bromodomain of BRD4 (BRD4-D1 selective), or pan-D1 biased, for assessing their cellular and in vivo efficacy and safety profile in two models of inflammatory liver disease. We compare their effects to known pan-D2 and pan-BET inhibitors. Our results show that pan-D1 biased inhibitor, 3, is as efficacious as the pan-BET inhibitor I-BET151 in reducing inflammation from LPS-induced and drug-induced toxicity, whereas pan-D2 inhibitors are less effective. BRD4-D1 selective inhibitors, 1 and 2, are also efficacious; however, new inhibitors with improved cellular target engagement will be necessary to more thoroughly assess their effects. Finally, BRD4-D1 selective inhibitors are better tolerated in a preclinical model of thrombocytopenia than pan-D1 biased inhibitors, while gastrointestinal (GI) toxicity may be a BRD4-driven effect. These results highlight the importance of assessing specific BET protein and bromodomain functions due to their varying roles in diverse disease models.

Abstract Matrix metalloproteinases (MMPs) regulate the degradation of extracellular matrix (ECM) components in biological processes. MMP activity is controlled by natural tissue inhibitors of metalloproteinases (TIMPs) that non-selectively inhibit the function of multiple MMPs via interaction with the MMPs' Zn 2+ -containing catalytic pocket. Recent studies suggest that TIMPs engineered to confer MMP specificity could be exploited for therapeutic purposes, but obtaining specific TIMP-2 inhibitors has proved to be challenging. Here, in an effort to improve MMP specificity, we incorporated the metal-binding non-canonical amino acids (NCAAs), 3,4-dihydroxyphenylalanine (L-DOPA) and (8-hydroxyquinolin-3-yl)alanine (HqAla), into the MMP-inhibitory N-terminal domain of TIMP2 (N-TIMP2) at selected positions that interact with the catalytic Zn 2+ ion (S2, S69, A70, L100) or with a structural Ca 2+ ion (Y36). Evaluation of the inhibitory potency of the NCAA-containing variants towards MMP-2, MMP-9 and MMP-14 in vitro revealed that most showed a significant loss of inhibitory activity towards MMP-14, but not towards MMP-2 and MMP-9, resulting in increased specificity towards the latter proteases. Substitutions at S69 conferred the best improvement in selectivity for both L-DOPA and HqAla variants. Molecular modeling revealed how MMP-2 and MMP-9 are better able to accommodate the bulky NCAA substituents at the intermolecular interface with N-TIMP2. The models also showed that, rather than coordinating to Zn 2+ , the NCAA side chains formed stabilizing polar interactions at the intermolecular interface with MMP-2 and MMP-9. The findings illustrate how incorporation of NCAAs can be used to probe and exploit differential tolerance for substitution within closely related protein-protein complexes to achieve improved specificity.

Introduction: The CARMA1-BCL10-MALT1 (CBM) complex plays a crucial role in antigen receptor-induced activation of NF-κB transcription factor and subsequent lymphocyte activation. MALT1, the effector molecule of the CBM complex, functions both as a scaffold to recruit and activate components of the NF-κB signaling machinery, and as a protease to enzymatically cleave and inactivate multiple substrates including several negative regulators of NF-κB signaling. Deregulated/constitutive activation of MALT1, which can occur due to gain-of-function mutations of the B cell receptor, CARMA1, BCL10 or chromosomal translocation involving the MALT1 gene, underlies the pathogenesis of various lymphoid malignancies including activated B-cell type-diffuse large B-cell lymphoma (ABC-DLBCL). We previously identified G-protein-coupled receptor kinase 2 (GRK2) as a tumor suppressor in MALT1-dependent lymphomas which binds MALT1 and inhibits both MALT1 scaffolding and proteolytic activities. Notably, GRK2 mRNA levels are markedly lower in a subset of DLBCL tumors comparing to normal B cell controls and lower GRK2 expression in ABC-DLBCL is associated with reduced patient survival. Based on these findings, we sought to investigate how GRK2 levels are regulated in ABC-DLBCL. Methods and Results: Using DICER1-knock down and knock-out cells, we showed that impaired miRNA processing significantly increases GRK2 protein levels. We then conducted bioinformatic analysis of patient tumor samples and performed screening via microRNA Data Integration Portal (mirDIP) to identify microRNAs targeting GRK2 in ABC-DLBCL. Direct targeting of GRK2 by candidate miRNAs was then confirmed using a GRK2 3′UTR reporter assay. We found that ABC-DLBCL cell lines, OCI-LY3 and TMD8, which demonstrate lower GRK2 mRNA expression compared to primary B cells, also show elevated expression of candidate GRK2-targeting microRNAs. Stable overexpression of miR-125a, 125b, and 148b in OCI-Ly3 or TMD8 cells leads to reduced GRK2 mRNA and protein expression, enhanced MALT1 activity and increased cell proliferation. Conversely, in vitro inhibition of candidate miRNAs using anti-miRNA Locked Nucleic Acids (LNA) inhibitors leads to enhanced GRK2 expression, reduced MALT1 activity and decreased cell proliferation. Importantly, treatment of mice with inhibitors of miR-125b and miR-148b reduces the growth of ABC-DLBCL xenograft tumors in vivo. Conclusions: We have identified a set of miRNAs (miR-148b, 125a and 125b) which down-regulate GRK2 expression in ABC-DLBCL, which in turn enhances MALT1 scaffolding and proteolytic activities, and leads to increased tumor cell proliferation. We find that inhibitors of these miRNAs enhance GRK2 expression and thereby suppress MALT1 activity and MALT1-dependent tumor cell proliferation, both in vitro and in vivo. These studies suggest that microRNA inhibitors which enhance GRK2 expression could represent a novel approach for restraining MALT1-dependent lymphomagenesis. Keywords: tumor biology and heterogeneity; aggressive B-cell non-Hodgkin lymphoma; molecular targeted therapies Potential sources of conflict of interest: A. M. Melnick Consultant or advisory role: Treeline Biosciences and Ipsen Other remuneration: research funding from Janssen, Epizyme, Treeline Biosciences and Daiichi Sankyo P. C. Lucas Stock ownership: Amgen L. M. McAllister-Lucas Stock ownership: Amgen Honoraria: Schroedinger