Src homology 2-containing protein tyrosine phosphatase 2 (SHP2) is the first reported nonreceptor oncogenic tyrosine phosphatase connecting multiple signal transduction cascades and exerting immunoinhibitory function through the PD-1 checkpoint receptor. As part of a drug discovery program aimed at obtaining novel allosteric SHP2 inhibitors, a series of pyrazopyrazine derivatives bearing an original bicyclo[3.1.0]hexane basic moiety on the left-hand side region of the molecule were identified. We report herein the discovery process, the in vitro pharmacological profile, and the early developability features of compound 25, one of the most potent members of the series.

Chronic hepatitis B (CHB) is a major worldwide public health problem and novel anti-HBV therapies preventing liver disease progression to cirrhosis and hepatocellular carcinoma are urgently needed. Over the last several years, capsid assembly modulators (CAM) have emerged as clinically effective anti-HBV agents which can inhibit HBV replication in CHB patients. As part of a drug discovery program aimed at obtaining novel CAM endowed with high in vitro and in vivo antiviral activity, we identified a novel series of sulfamoylbenzamide (SBA) derivatives. Compound 10, one of the most in vitro potent SBA-derived CAM discovered to date, showed excellent pharmacokinetics in mice suitable for oral dosing. When studied in a transgenic mouse model of hepatic HBV replication, it was considerably more potent than NVR 3-778, the first sulfamoylbenzamide (SBA) CAM that entered clinical trials for CHB, at reducing viral replication in a dose-dependent fashion. We present herein the discovery process, the SAR analysis and the pre-clinical profile of this novel SBA CAM.

The marine natural product Largazole is the most potent Class I HDAC inhibitor identified to date. Since its discovery, many research groups have been attracted by the structural complexity and the peculiar anticancer activity, due to its capability to discriminate between tumor cells and normal cells. Herein, we discuss the synthesis and the in vitro biological profile of hybrid analogues of Largazole, as dual HDAC inhibitor and nitric oxide (NO) donors, potentially useful as anticancer agents. In particular, the metabolic stability of the modified thioester moiety of Largazole, bearing the NO-donor function/s, the in vitro release of NO, and the antiproliferative activity in tumor cell lines are presented.

Acid-sensing ion channels (ASICs) are a family of ion channels permeable to cations and largely responsible for the onset of acid-evoked ion currents both in neurons and in different types of cancer cells, thus representing a potential target for drug discovery. Owing to the limited attention ASIC2 has received so far, an exploratory program was initiated to identify ASIC2 inhibitors using diminazene, a known pan-ASIC inhibitor, as a chemical starting point for structural elaboration. The performed exploration enabled the identification of a novel series of ASIC2 inhibitors. In particular, compound 2u is a brain penetrant ASIC2 inhibitor endowed with an optimal pharmacokinetic profile. This compound may represent a useful tool to validate in animal models in vivo the role of ASIC2 in different neurodegenerative central nervous system pathologies.

Since the time of its identification, the natural compound largazole rapidly caught the attention of the medicinal chemistry community for its impressive potency as an inhibitor of histone deacetylases (HDACs) and its strong antiproliferative activity against a broad panel of cancer cell lines. The design of largazole analogues is an expanding field of study, due to their remarkable potential as novel anticancer therapeutics. At present, a large ensemble of largazole analogues has been reported, allowing the identification of important structure-activity relationships (SAR) that can guide the design of novel compounds with improved HDAC inhibitory profiles, anticancer activity, and pharmacokinetic properties. The aim of this review is to concisely summarize the information obtained by biological evaluations of the various largazole analogues reported to date, with particular attention given to the latest analogues, as well as to analyze the various SAR obtained from this data, with the purpose of providing useful guidelines for the development of novel potent and selective HDAC inhibitors to be used as anticancer agents.

Defective apoptosis is a hallmark of the progression of B chronic lymphocytic leukaemia (B-CLL). Smac-mimetics have been shown to induce apoptosis in several tumours. We describe the in vitro pro-apoptotic activity and regulation of the molecular pathway induced by new Smac-mimetics in B-CLL. The cytotoxic effect was significantly higher in B-CLL samples than in healthy controls. No significant synergistic effect was observed in combined treatment. In conclusion one of our compounds (Smac66), used as monotherapy and not in combination, is highly active against B-CLL cells thus suggesting a promising therapeutic potential as a new class of antileukemic drugs in haematology.

Novel pro-apoptotic, homo- and heterodimeric Smac mimetics/IAPs inhibitors based on the N-AVPI-like 4-substituted 1-aza-2-oxobicyclo[5.3.0]decane scaffold were prepared from monomeric structures connected through a head-head (8), tail-tail (9) or head-tail (10) linker. The selection of appropriate decorating functions for the scaffolds, and of rigid and flexible linkers connecting them, is described. The synthesis, purification and analytical characterization of each prepared dimer 8-10 is thoroughly described.

A set of phenyl-substituted Smac mimetics/IAP inhibitor analogues of lead compound 2a was synthesized, aiming to retain its strong cell-free potency while increasing its bioavailability. Seventeen compounds 2b–r were prepared and characterized in vitro, using cell-free and cellular assays. Among them, the p-CF3 substituted analogue 2m showed the best permeability through cell membranes, and was selected for further in vitro and in vivo studies due to its strong, sub-micromolar cellular potency.

Design and synthesis of an HDAC inhibitor and its merger with three tubulin binders to create releasable conjugate compounds is described. The biological evaluation includes: (a) in vitro reactivity with glutathione, (b) antiproliferative activity, (c) cell cycle analysis and (d) quantification of protein acetylation. The cellular pharmacology study indicated that the HDAC-inhibitor-drug conjugates retained antimitotic and proapoptotic activity with a reduced potency.