BET in hematologic tumors: Immunity, pathogenesis, clinical trials and drug combinations

Targeting hematological malignancies with isoxazole derivatives

Compounds with a heterocyclic isoxazole ring are well known for their diverse biologic activities encompassing antimicrobial, antipsychotic, immunosuppressive, antidiabetic and anticancer effects. Recent studies on hematological malignancies have also shown that some of the isoxazole-derived compounds feature encouraging cancer selectivity, low toxicity to normal cells and ability to overcome cancer drug resistance of conventional treatments. These characteristics are particularly promising because patients with hematological malignancies face poor clinical outcomes caused by cancer drug resistance or relapse of the disease. This review summarizes the knowledge on isoxazole-derived compounds toward hematological malignancies and provides clues on their mechanism(s) of action (apoptosis, cell cycle arrest, ROS production) and putative pharmacological targets (c-Myc, BET, ATR, FLT3, HSP90, CARM1, tubulin, PD-1/PD-L1, HDACs) wherever known.

PROteolysis-Targeting Chimeras (PROTACs) in leukemia: overview and future perspectives

Leukemia is a heterogeneous group of life-threatening malignant disorders of the hematopoietic system. Immunotherapy, radiotherapy, stem cell transplantation, targeted therapy, and chemotherapy are among the approved leukemia treatments. Unfortunately, therapeutic resistance, side effects, relapses, and long-term sequelae occur in a significant proportion of patients and severely compromise the treatment efficacy. The development of novel approaches to improve outcomes is therefore an unmet need. Recently, novel leukemia drug discovery strategies, including targeted protein degradation, have shown potential to advance the field of personalized medicine for leukemia patients. Specifically, PROteolysis-TArgeting Chimeras (PROTACs) are revolutionary compounds that allow the selective degradation of a protein by the ubiquitin-proteasome system. Developed against a wide range of cancer targets, they show promising potential in overcoming many of the drawbacks associated with conventional therapies. Following the exponential growth of antileukemic PROTACs, this article reviews PROTAC-mediated degradation of leukemia-associated targets. Chemical structures, in vitro and in vivo activities, pharmacokinetics, pharmacodynamics, and clinical trials of PROTACs are critically discussed. Furthermore, advantages, challenges, and future perspectives of PROTACs in leukemia are covered, in order to understand the potential that these novel compounds may have as future drugs for leukemia treatment.

Co-inhibition of BET and NAE enhances BIM-dependent apoptosis with augmented cancer therapeutic efficacy

Agents that inhibit bromodomain and extra-terminal domain (BET) proteins have been actively tested in the clinic as potential anticancer drugs. NEDD8-activating enzyme (NAE) inhibitors, represented by MLN4924, target the only activation enzyme in the neddylation pathway that has been identified as an attractive target for cancer therapy. In this study, we focus on the combination of BET inhibitors (BETis) and NAE inhibitors (NAEis) as a cancer therapeutic strategy and investigate its underlying mechanisms to explore and expand the application scope of both types of drugs. The results showed that this combination synergistically inhibited the proliferative activity of tumor cells from different tissues. Compared to a single drug, combination therapy had a weak effect on cycle arrest but significantly enhanced cell apoptosis. Furthermore, the growth of NCI-H1975 xenografts in nude mice was significantly inhibited by the combination without obvious body weight loss. Research on the synergistic mechanism demonstrated that combination therapy significantly increased the mRNA and protein levels of the proapoptotic gene BIM. The inhibition and knockout of BIM significantly attenuated the apoptosis induced by the combination, whereas the re-expression of BIM restored the synergistic effects, indicating that BIM induction plays a critical role in mediating the enhanced apoptosis induced by the co-inhibition of BET and NAE. Together, the enhanced transcription mediated by miR-17-92 cluster inhibition and reduced degradation promoted the increase in BIM levels, resulting in a synergistic effect. Collectively, these findings highlight the need for further clinical investigation into the combination of BETi and NAEi as a promising strategy for cancer therapy.

AI in Pharma: Transforming Drug Discovery and Strategic Management with MYC-Modulating Compounds and BET Protein Inhibitors

The landscape of pharmaceutical R&D is being reshaped by the synergistic integration of Artificial Intelligence (AI) and groundbreaking drug discoveries, mainly focusing on MYC-modulating compounds and BET protein inhibitors. This Patent Highlight delves into this convergence, illustrating a transformative shift in the pharmaceutical industry's approach to drug development, strategic management, and treating various diseases, from cancer to inflammatory and fibrotic disorders.

A novel pan-selective bromodomain inhibitor for epigenetic drug design

For a long time, the development of bromodomain (BD) inhibitors (BDi) was almost exclusively related to the BET family. More recently, BDi for BDs outside the BET family have also been developed. Here we present a novel pan-BDi with micromolar affinities to various BDs, and nanomolar affinities to representatives of BD families I, II (Bromodomain and Extra-Terminal Domain (BET) family), III, and IV. The inhibitor shows a broad activity profile with nanomolar growth inhibition (GI50) values on various cancer cell lines. Subsequently, we were able to control the selectivity of the inhibitor by simple modifications and turned it into a highly selective BRD9 inhibitor.

Small-Molecule PROTACs for Cancer Immunotherapy

Unsatisfactory physicochemical properties of macromolecular drugs seriously hinder their application in tumor immunotherapy. However, these problems can be effectively solved by small-molecule compounds. In the promising field of small-molecule drug development, proteolysis targeting chimera (PROTAC) offers a novel mode of action in the interactions between small molecules and therapeutic targets (mainly proteins). This revolutionary technology has shown considerable impact on several proteins related to tumor survival but is rarely exploited in proteins associated with immuno-oncology up until now. This review attempts to comprehensively summarize the well-studied and less-developed immunological targets available for PROTAC technology, as well as some targets to be explored, aiming to provide more options and opportunities for the development of small-molecule-based tumor immunotherapy. In addition, some novel directions that can magnify and broaden the protein degradation efficiency are mentioned to improve PROTAC design in the future.