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Background: Sodium/glucose co-transporter 2 (SGLT2) inhibitors exert robust cardioprotective effects against heart failure in diabetes patients and there is intense interest to identify the underlying molecular mechanisms that afford this protection. As the induction of the late component of the cardiac sodium channel current (late-I Na ) is involved in the etiology of heart failure, we investigated whether these drugs inhibit late-I Na . Methods: Electrophysiological, in silico molecular docking, molecular, calcium imaging and whole heart perfusion techniques were employed to address this question. Results: The SGLT2 inhibitor empagliflozin reduced late-I Na in cardiomyocytes from mice with heart failure and in cardiac Nav1.5 sodium channels containing the LQT3 mutations R1623Q or ∆KPQ. Empagliflozin, dapagliflozin and canagliflozin are all potent and selective inhibitors of H 2 O 2 -induced late-I Na (IC 50s = 0.79, 0.58 and 1.26 µM respectively) with little effect on peak-I Na . In mouse cardiomyocytes, empagliflozin reduced the incidence of spontaneous calcium transients induced by the late-I Na activator veratridine in a similar manner to tetrodotoxin, ranolazine and lidocaine. The putative binding sites for empagliflozin within Nav1.5 were investigated by simulations of empagliflozin docking to a 3D homology model of human Nav1.5 and point mutagenic approaches. Our results indicate that empagliflozin binds to Nav1.5 in the same region as local anaesthetics and ranolazine. In an acute model of myocardial injury, perfusion of isolated mouse hearts with empagliflozin or tetrodotoxin prevented activation of the cardiac NLRP3 inflammasome and improved functional recovery after ischemia. Conclusions: Our results provide evidence that late-I Na may be an important molecular target in the heart for the SGLT2 inhibitors, contributing to their unexpected cardioprotective effects.

Synthetic and natural peptides that act as nonselective melanocortin receptor agonists have been found to be anorexigenic and to stimulate erectile activity. We report the design and development of 1, a potent, selective (1184-fold vs MC3R, 350-fold vs MC5R), small-molecule agonist of the MC4 receptor. Pharmacological testing confirms the food intake lowering effects of MC4R agonism and suggests another role for the receptor in the stimulation of erectile activity.

Blockade of the programmed cell death 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) interaction has emerged as a powerful strategy in cancer immunotherapy. Recently, there have been enormous efforts to develop potent PD-1/PD-L1 inhibitors. In particular, Bristol-Myers Squibb (BMS) and Aurigene Discovery Technologies have individually disclosed several promising PD-1/PD-L1 inhibitors, whose detailed experimental data are not publicly disclosed. In this work, we report the rigorous and systematic in vitro characterization of a selected set of potent PD-1/PD-L1 macrocyclic peptide (BMSpep-57) and small-molecule inhibitors (BMS-103, BMS-142) from BMS and a peptidomimetic small-molecule inhibitor from Aurigene (Aurigene-1) using a series of biochemical and cell-based assays. Our results confirm that BMS-103 and BMS-142 are strongly active in biochemical assays; however, their acute cytotoxicity greatly compromised their immunological activity. On the other hand, Aurigene-1 did not show any activity in both biochemical and immunological assays. Furthermore, we also report the discovery of a small-molecule immune modulator, whose mode-of-action is not clear; however, it exhibits favorable drug-like properties and strong immunological activity. We hope that the results presented here will be useful in guiding the development of next-generation PD-1/PD-L1 small molecule inhibitors.

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Catalytic transfer hydrogenation has been conducted under microwave irradiation in open vessels using high-boiling solvents such as ethylene glycol (bp 198 °C) as the microwave energy transfer agent. Reduction of double bonds and hydrogenolysis of several functional groups were carried out safely and rapidly (3-5 min) at about 110-130 °C with 10% Pd/C as an efficient catalyst and ammonium formate as the hydrogen donor. Diverse types of β-lactam synthons were prepared by the reduction of ring substituents containing alkene and alkylidene groups or conjugated unsaturated esters. Cleavage of the β-lactam ring by hydrogenolysis of the N-C 4 bond of 4-aryl-2-azetidinones was a facile reaction with 10% Pd/C as the catalyst; but no ring scission occurred when Raney nickel catalyst was employed. Dehalogenation of aromatic compounds was also successful with ammonium formate and Pd/C catalyst. Hydrogenolysis of phenylhydrazone of methyl benzoylformate gave the methyl ester of phenylglycine in excellent yield. The techniques described here for microwave assisted hydrogenation are safe, rapid, and efficient and are suitable for research investigation as well as for undergraduate and high school laboratory exercises.

The ERCC1–XPF heterodimer is a 5′–3′ structure-specific endonuclease, which plays an essential role in several DNA repair pathways in mammalian cells. ERCC1–XPF is primarily involved in the repair of chemically induced helix-distorting and bulky DNA lesions, such as cyclobutane pyrimidine dimers (CPDs), and DNA interstrand cross-links. Inhibition of ERCC1–XPF has been shown to potentiate cytotoxicity of platinum-based drugs and cyclophosphamide in cancer cells. In this study, the previously described ERCC1–XPF inhibitor 4-((6-chloro-2-methoxyacridin-9-yl)­amino)-2-((4-methylpiperazin-1-yl)­methyl)­phenol (compound 1) was used as a reference compound. Following the outcome of docking-based virtual screening (VS), we synthesized seven novel derivatives of 1 that were identified in silico as being likely to have high binding affinity for the ERCC1–XPF heterodimerization interface by interacting with the XPF double helix–hairpin–helix (HhH2) domain. Two of the new compounds, 4-((6-chloro-2-methoxyacridin-9-yl)­amino)-2-((4-cyclohexylpiperazin-1-yl)­methyl)­phenol (compound 3) and 4-((6-chloro-2-methoxyacridin-9-yl)­amino)-2-((4-(2-(dimethylamino)­ethyl) piperazin-1-yl) methyl) phenol (compound 4), were shown to be potent inhibitors of ERCC1–XPF activity in vitro. Compound 4 showed significant inhibition of the removal of CPDs in UV-irradiated cells and the capacity to sensitize colorectal cancer cells to UV radiation and cyclophosphamide.

Modern cancer therapies, mainly ionizing radiation and certain classes of chemotherapies target DNA. Although these treatments disrupt the genome, their rationale is clear. They prevent cancer cells from dividing and proliferating. Nevertheless, cancer cells can survive by over-activating a wide range of DNA repair pathways to eliminate the induced damage. In this context, DNA repair mechanisms are considered to be a vital target to improve cancer therapy and reduce the resistance to many DNA damaging agents currently in use as standard-of-care treatments. Here, we focus on two important DNA repair pathways, namely base excision repair (BER) and nucleotide excision repair (NER). Specifically, our focus is on two protein targets that are linked to the hallmark "relapse" and "drug resistance" phenomena. These are Excision Repair Cross-Complementation Group 1 (ERCC1), and DNA polymerase beta (pol β). The former is a key player in NER, while the latter is the error-prone polymerase of BER. Our objective is to list all known inhibitors for the two targets and provide an overview of the great efforts that were made in their discovery. While in the DNA pol β case more than sixty inhibitors were identified, very few inhibitors have been discovered on the ERCC1 side. It is hoped that this review will assist in the discovery of novel, potent and specific drug candidates aimed at improving existing cancer therapies including ionizing radiation, bleomycin, monofunctional alkylating agents and cisplatin.