Progenra (United States)

Malaria is a global health threat that requires immediate attention. Malaria is caused by the protozoan parasite Plasmodium, the most severe form of which is Plasmodium falciparum. The methylerythritol phosphate (MEP) pathway of isoprenoid biosynthesis is essential to the survival of many human pathogens, including P. falciparum, but is absent in humans, and thus shows promise as a new antimalarial drug target. The enzyme 1-deoxy-d-xylulose 5-phosphate reductoisomerase (IspC) catalyzes the first committed step in the MEP pathway. In addition to a divalent cation (Mg2+), the enzyme requires the substrates 1-deoxy-D-xylulose 5-phosphate (DXP) and NADPH to catalyze its reaction. We designed N-alkoxy and N-acyl fosmidomycin analogs to inhibit the activity of P. falciparum IspC in a bisubstrate manner. Enzyme assays reveal that the N-alkoxy fosmidomycin analogs have a competitive mode of inhibition relative to both the DXP- and NADPH-binding sites, confirming a bisubstrate mode of inhibition. In contrast, the N-acyl fosmidomycin analogs demonstrate competitive inhibition with respect to DXP but uncompetitive inhibition with respect to NADPH, indicating monosubstrate inhibitory activity. Our results will have a positive impact on the discovery of novel antimalarial drugs.

Abstract The ubiquitin-specific protease 7 (USP7) has emerged as an attractive oncology/immune-oncology target owing to its critical roles in several cancer-related signaling pathways as well as its essential role in maintaining functions of Foxp3+ T-regulatory cells (Tregs), the key players in tumor immune evasion. Progenra has developed a series of compounds that inhibit purified USP7 selectively and attenuate USP7 activity in cells and in vivo; these inhibitors exert antitumor activity directly and also facilitate immune-mediated antitumor activity by suppressing Treg functions. However, the precise mechanism of action of these compounds remains unclear. In this study, using a combination of NMR spectroscopy, mass spectrometry, and single amino-acid substitution approaches, we have now demonstrated that our USP7 inhibitors specifically target the catalytic pocket of USP7 and modify its active site cysteine (Cys223) by forming a covalent adduct. Consistent with the covalent binding mechanism, pharmacokinetic studies revealed long-lasting, irreversible USP7 inhibition after a short pulse treatment with inhibitor, accompanied by changes in the level and ubiquitylation of various pharmacodynamic markers, including the Treg lineage-specific transcription factor Foxp3. Detailed knowledge of the mechanism of USP7 inhibition will permit the rational design of improved inhibitors as a new class of anticancer agent. Citation Format: Feng Wang, Jian Wu, Liqing Wang, Ivan Sokirniy, Hui Wang, Lee Chen, Brigid Cunnion, David Sterner, Charles Grove, Thomas Bregnard, Joseph Weinstock, Michael Mattern, Irina Bezsonova, Wayne W. Hancock, Suresh Kumar. Characterization of selective active-site targeted covalent inhibitors of usp7 [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B193.

Abstract Immune evasion is a hallmark feature of tumors as they employ various strategies to suppress the immune system's ability to recognize and destroy cancer cells. T cell checkpoint inhibitors such as anti-PD1 and anti-CTLA-4 antibodies spearhead the immune response against a variety of tumors. Numerous studies suggest that the complex immunosuppressive milieux require the development of additional therapeutic agents to potentiate active drugs and thereby broaden the utility and increase the therapeutic indices of revolutionary immune-oncology treatment modalities. The presence of immunosuppressive regulatory T cells (Tregs) in tumors, keeping tumoricidal Teffector cells in check, signals poor prognosis. Thus, depletion of Tregs or impairment of Treg function is an attractive therapeutic approach for cancer. USP7, a deubiquitylase enzyme implicated as a critical node in several cancer signaling pathways, has recently emerged as an essential factor in maintaining Treg functions. Progenra identified small molecule USP7 inhibitors and employed them to show that Treg specific inhibition of USP7 results in impairment of Treg function leading to immune activation, commensurate with the ablation of Foxp3, a transcription factor that is a target of USP7 and is essential to Treg activation. This USP7 inhibitor class was subsequently lead optimized, and selected USP7 inhibitors were evaluated in ADME/PK studies and shown to impair Treg functions and to exhibit powerful anti-tumor activity against syngeneic lung tumor models in immunocompetent mice. In addition, Progenra's USP7 inhibitors significantly augmented the antitumor activity of anti-PD1 antibody, CAR T cell therapy, and cancer vaccines. These studies provide a strong rationale for the use of USP7 inhibitors in combination therapy protocols to improve the efficacy of currently approved cancer immunotherapy agents. Citation Format: Suresh Kumar, Jian Wu, Liquing Wang, Feng Wang, Matthew P. Kodrasov, Saket Agarwal, Ivan Sokirniy, Thomas Yeckley, Joseph Weinstock, Michael R. Mattern, Wayne W. Hancock. Small molecule T-reg inhibitors for cancer immunotherapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 559.

Rheumatoid arthritis (RA) significantly affects quality of life. We recently clonedsynoviolin, a RING-type E3 ubiquitin ligase implicated in the endoplasmicreticulum-associated degradation (ERAD) pathway. Synoviolin is highly expressed inrheumatoid synovial cells and may be involved in the pathogenesis of RA. Inhibition ofsynoviolin activity is a potentially useful therapeutic approach for the treatment of RA.We conducted a high-throughput screen of small molecules to find inhibitors of synoviolinautoubiquitination activity. We identified two classes of small molecules, named LS-101and LS-102, which inhibited synoviolin activity. LS-102 selectively inhibited synoviolinenzymatic activity, while LS-101 inhibited a broad array of RING-type E3 ligases.Moreover, these inhibitors suppressed the proliferation of rheumatoid synovial cells, andsignificantly reduced the severity of disease in a mouse model of RA. Our results suggestthat inhibition of synoviolin is a potentially useful approach in the treatment of RA.

Select engineering characteristics of crushed glass produced using two processing techniques (crushing versus screening) to an American Society of State Highway and Transportation Officials No. 10 gradation were experimentally evaluated. The crushed glass samples were classified as well graded sands with gravel (SW) and exhibited excellent strength and workability characteristics. The low specific gravity (2.49) contributed to crushed glass having compacted maximum dry densities on the order of 16.6–16.8 and 17.5-18.3kN/m3 by the standard and modified Proctor compaction tests, respectively. Direct shear friction angles were measured between 47 and 62° at normal stresses ranging from 0to200kPa. Friction angles obtained by drained triaxial shear were on the order of 48° for similar stress ranges. Measured hydraulic conductivities were on the order of 1-6×10-4cm/s. The results indicate that crushed glass is a readily available, freely draining, environmentally clean, relatively low cost material whose engineering performance properties generally equal or exceed those of most natural aggregates. Despite these favorable characteristics, there are many real and perceived barriers to increasing the beneficial use of crushed glass, and key examples are provided in an effort to illustrate these unnecessary barriers.