B-cell lymphoma-2 family proteins in the crosshairs: Small molecule inhibitors and activators for cancer therapy.

The B-cell lymphoma-2 (BCL-2) family of proteins plays a crucial role in the regulation of apoptosis, offering a dual mechanism for its control. Numerous studies have established a strong association between gene disorders of these proteins and the proliferation of diverse cancer cell types. Consequently, the identification and development of drugs targeting BCL-2 family proteins have emerged as a prominent area in antitumor therapy. Over the last two decades, several small-molecules have been designed to modulate the protein-protein interactions between anti- and proapoptotic BCL-2 proteins, effectively suppressing tumor growth and metastasis in vivo. The primary focus of research has been on developing BCL-2 homology 3 (BH3) mimetics to target antiapoptotic BCL-2 proteins, thereby competitively releasing proapoptotic BCL-2 proteins and restoring the blocked intrinsic apoptotic program. Additionally, for proapoptotic BCL-2 proteins, exogenous small molecules have been explored to activate cell apoptosis by directly interacting with executioner proteins such as BCL-2-associated X protein (BAX) or BCL-2 homologous antagonist/killer protein (BAK). In this comprehensive review, we summarize the inhibitors and activators (sensitizers) of BCL-2 family proteins developed over the past decades, highlighting their discovery, optimization, preclinical and clinical status, and providing an overall landscape of drug development targeting these proteins for therapeutic purposes.

S2DV: converting SMILES to a drug vector for predicting the activity of anti-HBV small molecules.

In the past few decades, chronic hepatitis B caused by hepatitis B virus (HBV) has been one of the most serious diseases to human health. The development of innovative systems is essential for preventing the complex pathogenesis of hepatitis B and reducing side effects caused by drugs. HBV inhibitory drugs have been developed through various compounds, and they are often limited by routine experimental screening and delay drug development. More recently, virtual screening of compounds has gradually been used in drug research with strong computational capability and is further applied in anti-HBV drug screening, thus facilitating a reliable drug screening process. However, the lack of structural information in traditional compound analysis is an important hurdle for unsatisfactory efficiency in drug screening. Here, a natural language processing technique was adopted to analyze compound simplified molecular input line entry system strings. By using the targeted optimized word2vec model for pretraining, we can accurately represent the relationship between the compound and its substructure. The machine learning model based on training results can effectively predict the inhibitory effect of compounds on HBV and liver toxicity. The reliability of the model is verified by the results of wet-lab experiments. In addition, a tool has been published to predict potential compounds. Hence, this article provides a new perspective on the prediction of compound properties for anti-HBV drugs that can help improve hepatitis B diagnosis and further develop human health in the future.

Synthesis and Biological Evaluation of Matijin-Su Derivatives as Potential Antihepatitis B Virus and Anticancer Agents.

A series of Matijin-Su (MTS, (2S)-2-{[(2S)-2-benzamido-3-phenylpropanoyl]amino}-3-phenylpropyl acetate) derivatives were synthesized and evaluated for their anti-HBV and cytotoxic activities in vitro. Six compounds (4g, 4j, 5c, 5g, 5h and 5i) showed significant inhibition against HBV DNA replication with the IC50 values in range of 2.18 - 8.55 µm, which were much lower than that of positive control lamivudine (IC50 82.42 µm). In particular, compounds 5h (IC50 2.18 µm; SI 151.59) and 5j (IC50 5.65 µm; SI 51.16) displayed relatively low cytotoxicities, resulting in high SI values. Notably, besides the anti-HBV DNA replication activity, compound 4j also exhibited more potent in vitro cytotoxic activity than 5-fluorouracil in two hepatocellular carcinoma cell (HCC) lines (QGY-7701 and SMMC-7721), indicating that 4j may be a promising lead for the exploration of drugs with dual therapeutic effects on HBV infection and HBV-induced HCC.

Discovery of Phenylpyrazole Derivatives as a New Class of Selective Inhibitors of MCL-1 with Antitumor Activity.

MCL-1, an antiapoptotic member of the BCL-2 family, is dysregulated and overexpressed in various tumors. In tumors with MCL-1 overexpression, selective inhibitors of MCL-1 are expected to overcome the drug resistance caused by BCL-2 inhibitors currently used in clinical treatment. Here, we employed docking-based virtual screening to identify an active hit, LC126, with binding affinity around 10 µM for MCL-1 and BCL-2. Under the guidance of structure-based design, we obtained a few selective inhibitors of MCL-1 after three rounds of structural optimization. The representative compound GQN-B37-E exhibited binding affinity for MCL-1 at the submicromolar range (K i = 0.6 µM) without apparent binding to BCL-2 or BCL-XL. 15N-heteronuclear single-quantum coherence NMR spectra suggested that this compound binds to the BH3-domain-binding pocket in the MCL-1 surface. Cellular assays revealed that GQN-B37-Me, the precursor of GQN-B37-E, is effective particularly on leukemia cells (such as H929 and MV-4-11) to induce caspase-dependent apoptosis. Its interaction with MCL-1 in cells was confirmed by coimmunoprecipitation. Administration of GQN-B37-Me to MV-4-11 xenograft mice at 50 mg/kg every 2 days for 20 days led to 43% tumor growth inhibition. GQN-B37-Me also exhibited reasonable in vitro stability in GSH and liver microsomes from several species. This new class of MCL-1 inhibitor may have potential to be further developed into a preclinical candidate for treating leukemia.

Structure-Based Optimization of 3-Phenyl-N-(2-(3-phenylureido)ethyl)thiophene-2-sulfonamide Derivatives as Selective Mcl-1 Inhibitors.

Selective Mcl-1 inhibitors may overcome the drug resistance caused by current anti-apoptotic Bcl-2 protein inhibitors in tumors with Mcl-1 overexpression. Based on previously discovered compounds with a 3-phenylthiophene-2-sulfonamide core moiety, in this work, we have obtained new compounds with improved binding affinity and/or selectivity under the guidance of structure-based design. The most potent compounds achieved sub-micromolar binding affinities to Mcl-1 (Ki ∼ 0.4 µM) and good cytotoxicity (IC50 < 10 µM) on several tumor cells. 15N-heteronuclear single-quantum coherence NMR spectra suggested that these compounds bound to the BH3-binding groove on Mcl-1. Several cellular assays revealed that FWJ-D4 as well as its precursor FWJ-D5 effectively induced caspase-dependent apoptosis, and their target engagement at Mcl-1 was confirmed by co-immunoprecipitation experiments. Treatment with FWJ-D5 at 50 mg/kg every 2 days on an RS4;11 xenograft mouse model for 22 days led to 75% reduction in tumor volume without body weight loss.

Design, synthesis and evaluation of novel phenyl propionamide derivatives as non-nucleoside hepatitis B virus inhibitors.

As an ongoing search for potent non-nucleoside anti-HBV agents with novel structures, we described a series of phenyl propionamide derivatives (3a-b, 4a-e, 7a-g, 8a-h and 9a-b) by pharmacophore fusion strategy in the present work. All the compounds exhibited an anti-HBV activity to some extent. Among them, compounds 8d and 9b displayed most potent anti-HBV activity with IC50 values on HBV DNA replication of 0.46 and 0.14 µM, respectively. And the selective index values of 8d and 9b were more than 217.39 and 153.14, suggesting that 8d and 9b exhibited favorable safety profiles. Interestingly, 8d and 9b possessed significantly antiviral activities against lamivudine and entecavir resistant HBV mutants with IC50 values of 0.77 and 0.32 µM. Notably, preliminary anti-HBV action mechanism studies showed that 8d could inhibit intracellular HBV pgRNA and RT activity of the HBV polymerase. Molecular docking studies suggested that compound 8d could fit into the dimer-dimer interface of HBV core protein by hydrophobic interaction. In addition, in silico prediction of physicochemical properties showed that 8d conformed well to the Lipinski's rule of five, suggesting its potential for use as a drug like molecule. Taken together, 8d possessed significantly anti-HBV activity, low toxicity, diverse anti-HBV mechanism and favorable physicochemical properties, and warranted further investigation as a promising non-nucleoside anti-HBV candidate.