LSD1 in drug discovery: From biological function to clinical application.

Lysine-specific demethylase 1 (LSD1) is a flavin adenine dinucleotide (FAD) dependent monoamine oxidase (MAO) that erases the mono-, and dimethylation of histone 3 lysine 4 (H3K4), resulting in the suppression of target gene transcriptions. Besides, it can also demethylate some nonhistone substrates to regulate their biological functions. As reported, LSD1 is widely upregulated and plays a key role in several kinds of cancers, pharmacological or genetic ablation of LSD1 in cancer cells suppresses cell aggressiveness by several distinct mechanisms. Therefore, numerous LSD1 inhibitors, including covalent and noncovalent, have been developed and several of them have entered clinical trials. Herein, we systemically reviewed and discussed the biological function of LSD1 in tumors, lymphocytes as well as LSD1-targeting inhibitors in clinical trials, hoping to benefit the field of LSD1 and its inhibitors.

Mining the Dynamical Properties of Substrate and FAD Binding Pockets of LSD1: Hints for New Inhibitor Design Direction.

Lysine-specific demethylase 1 (LSD1), a highly sophisticated epigenetic regulator, orchestrates a range of critical cellular processes, holding promising therapeutic potential for treating diverse diseases. However, the clinical research progress targeting LSD1 is very slow. After 20 years of research, only one small-molecule drug, BEA-17, targeting the degradation of LSD1 and CoREST has been approved by the U.S. Food and Drug Administration. The primary reason for this may be the lack of abundant structural data regarding its intricate functions. To gain a deeper understanding of its conformational dynamics and guide the drug design process, we conducted molecular dynamics simulations to explore the conformational states of LSD1 in the apo state and under the influence of cofactors of flavin adenine dinucleotide (FAD) and CoREST. Our results showed that, across all states, the substrate binding pocket exhibited high flexibility, whereas the FAD binding pocket remained more stable. These distinct dynamical properties are essential for LSD1's ability to bind various substrates while maintaining efficient demethylation activity. Both pockets can be enlarged by merging with adjacent pockets, although only the substrate binding pocket can shrink into smaller pockets. These new pocket shapes can inform inhibitor design, particularly for selectively FAD-competitive inhibitors of LSD1, given the presence of numerous FAD-dependent enzymes in the human body. More interestingly, in the absence of FAD binding, the united substrate and FAD binding pocket are partitioned by the conserved residue of Tyr761, offering valuable insights for the design of inhibitors that disrupt the crucial steric role of Tyr761 and the redox role of FAD. Additionally, we identified pockets that positively or negatively correlate with the substrate and FAD binding pockets, which can be exploited for the design of allosteric or concurrent inhibitors. Our results reveal the intricate dynamical properties of LSD1 as well as multiple novel conformational states, which deepen our understanding of its sophisticated functions and aid in the rational design of new inhibitors.

Computational study on the binding mechanism of allosteric drug TNO155 inhibiting SHP2E76A.

E76A mutations of SHP2 have been reported to associate with genetic developmental diseases and cancers, and TNO155 is one of the effective inhibitors targeted to the allosteric site 1, which has already entered the clinical stage. However, the detailed binding mechanism between them still needs further clarification at micro-atomic level. In this study, the binding mechanism of TNO155 inhibiting SHP2E76A and the superiorities of TNO155 at binding affinity and dynamic interactive behavior with SHP2E76A were probed utilizing a series of computational drug design technologies. The results show that SHP2E76A forms tighter interaction with TNO155 compared to SHP099. SHP2E76A-TNO155 exhibits the largest electrostatic interaction among all complex systems, which can be manifested by the strong hydrogen bond interactions formed by two electrically charged residues, Arg111 and Glu250. Notably, in SHP2E76A-TNO155 system, Asp489 makes an additional substantial beneficial contribution. The E76A mutation brings stronger residue positive correlation and a larger conformation fluctuation between N-CH2 and PTP domains, resulting in tighter binding between TNO155 and SHP2E76A. This study offers valuable insights for the further design and development of novel SHP2E76A allosteric inhibitors.

Simultaneous determination of folic acid photolysis products and oxidized guanine derivatives in plasma by liquid chromatography-tandem mass spectrometry.

Folic acid (FA) is easily photodegraded to yield 6-formylpterin and pterin-6-carboxylic acid, which can generate reactive oxygen species and result in the formation of oxidized guanine derivatives such as 8-hydroxy-2'-deoxyguanosine and 8-hydroxy-guanosine. In this study, we developed a simple, rapid, and sensitive liquid chromatography-tandem mass spectrometry strategy for the simultaneous determination of FA photolysis products and oxidized guanine derivatives in plasma samples. Chromatographic separation was performed on a Waters HSS T3 column (2.1 × 100 mm, 5.0 µm) with gradient elution at a flow rate of 0.25 mL/min. Plasma samples were first pretreated with 1% formic acid, followed by protein precipitation with methanol. The developed method showed good linear relationships between 1 and 2000 ng/mL (r2 > 0.99). The intra- and inter-day precisions ranged from 2.6% to 7.5% and from 2.5% to 6.5%, respectively. Recoveries of the analytes were between 75.4% and 112.4% with the relative standard deviation < 9.1%. Finally, the method was applied to quantify FA photolysis products and oxidized guanine derivatives in rats with light and non-light conditions.

New drug approvals for 2022: Synthesis and clinical applications.

The U.S. Food and Drug Administration has approved a total of 37 new drugs in 2022, which are composed of 20 chemical entities and 17 biologics. In particular, 20 chemical entities, including 17 small molecule drugs, 1 radiotherapy, and 2 diagnostic agents, provide privileged scaffolds, breakthrough clinical benefits, and a new mechanism of action for the discovery of more potent clinical candidates. The structure-based drug development with clear targets and fragment-based drug development with privileged scaffolds have always been the important modules in the field of drug discovery, which could easily bypass the patent protection and bring about improved biological activity. Therefore, we summarized the relevant valuable information about clinical application, mechanism of action, and chemical synthesis of 17 newly approved small molecule drugs in 2022. We hope this timely and comprehensive review could bring about creative and elegant inspiration on the synthetic methodologies and mechanism of action for the discovery of new drugs with novel chemical scaffolds and extended clinical indications.

Photoelectrochemical Engineering for Light-Assisted Rechargeable Metal Batteries: Mechanism, Development, and Future.

Rechargeable battery devices with high energy density are highly demanded by  our  modern society. The use of metal anodes is extremely attractive for future rechargeable battery devices. However, the notorious metal dendritic and instability of solid electrolyte interface issues pose a series of challenges for metal anodes. Recently, considering the indigestible dynamical behavior of metal anodes, photoelectrochemical engineering of light-assisted metal anodes have been rapidly developed since they efficiently utilize the integration and synergy of oriented crystal engineering and photocatalysis engineering, which provided a potential way to unlock the interface electrochemical mechanism and deposition reaction kinetics of metal anodes. This review starts with the fundamentals of photoelectrochemical engineering and follows with the state-of-art advance of photoelectrochemical engineering for light-assisted rechargeable metal batteries where photoelectrode materials, working principles, types, and practical applications are explained. The last section summarizes the major challenges and some invigorating perspectives for future research on light-assisted rechargeable metal batteries.

LSD1: an emerging face in altering the tumor microenvironment and enhancing immune checkpoint therapy.

Dysregulation of various cells in the tumor microenvironment (TME) causes immunosuppressive functions and aggressive tumor growth. In combination with immune checkpoint blockade (ICB), epigenetic modification-targeted drugs are emerging as attractive cancer treatments. Lysine-specific demethylase 1 (LSD1) is a protein that modifies histone and non-histone proteins and is known to influence a wide variety of physiological processes. The dysfunction of LSD1 contributes to poor prognosis, poor patient survival, drug resistance, immunosuppression, etc., making it a potential epigenetic target for cancer therapy. This review examines how LSD1 modulates different cell behavior in TME and emphasizes the potential use of LSD1 inhibitors in combination with ICB therapy for future cancer research studies.

Myofibroblast Deficiency of LSD1 Alleviates TAC-Induced Heart Failure.

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Lysine demethylase LSD1 delivered via small extracellular vesicles promotes gastric cancer cell stemness.

Several studies have examined the functions of nucleic acids in small extracellular vesicles (sEVs). However, much less is known about the protein cargos of sEVs and their functions in recipient cells. This study demonstrates the presence of lysine-specific demethylase 1 (LSD1), which is the first identified histone demethylase, in the culture medium of gastric cancer cells. We show that sEVs derived from gastric cancer cells and the plasma of patients with gastric cancer harbor LSD1. The shuttling of LSD1-containing sEVs from donor cells to recipient gastric cancer cells promotes cancer cell stemness by positively regulating the expression of Nanog, OCT4, SOX2, and CD44. Additionally, sEV-delivered LSD1 suppresses oxaliplatin response of recipient cells in vitro and in vivo, whereas LSD1-depleted sEVs do not. Taken together, we demonstrate that LSD1-loaded sEVs can promote stemness and chemoresistance to oxaliplatin. These findings suggest that the LSD1 content of sEV could serve as a biomarker to predict oxaliplatin response in gastric cancer patients.

Design, synthesis and biological evaluation of nitric oxide-releasing 5-cyano-6-phenyl-2, 4-disubstituted pyrimidine derivatives.

In this study, a series of nitric oxide (NO) -releasing 5-cyano-6-phenyl-2, 4-disubstituted pyrimidine derivatives were designed and synthesized. In the in vitro biological evaluation, compound 24l exhibited optimal antiproliferative activity against MGC-803 cells with the IC50 value of 0.95 µM, significantly better than that of the positive control 5-FU. In addition, preliminary mechanistic studies indicated that 24l inhibited colony formation and blocked MGC-803 cells in the G0/G1 phase. DAPI staining, reactive oxygen species and apoptosis assays demonstrated that 24l induced apoptosis of MGC-803 cells. Particularly, the most potent compound 24l produced the highest level of NO, and the antiproliferative activity was significantly reduced after preincubation with NO scavengers. In conclusion, compound 24l may be considered as a potential candidate antitumor agent.

Inhibition of lysine-specific demethylase 1 enhances the sensitivity of the chemotherapeutic drug doxorubicin in gastric cancer cell.

AIM: Lysine-Specific Demethylase 1 (LSD1) inhibitors have been developed and reached the clinic, but its effect in combination with cytotoxic chemotherapy is unclear. Here, we investigated the anti-tumor effect of LSD1 inhibitor GSK-LSD1 and its anti-tumor effect with the DNA damage drug doxorubicin (DOX) in gastric cancer (GC) cells. METHODS: Cells were treated with different concentrations of GSK-LSD1 to examine the anti-tumor effect versus cell viability by MTT and cell cycle arrest by flow cytometry. To explore whether LSD1 inhibitors can increase the anti-tumor effect of DNA damage drugs, cells were treated with DOX for 48 h after pretreatment with GSK-LSD1 for 48 h. Cell viability was detected by MTT and apoptosis-related proteins were examined by Western blot. Furthermore, anti-tumor efficacy of combination GSK-LSD1 with DOX was also measured in MGC-803 xenografts model in nude mice. RESULTS: The results showed that LSD1 was highly expressed in GC cell lines. Inhibition of LSD1 has a weak effect on cell viability and cell cycle. Moreover, LSD1 inhibitors pretreatment could significantly increase the anti-tumor effect of DOX. Further study found that inhibition of LSD1 can significantly enhance DOX-induced the apoptosis, accompanied by down-regulation of antiapoptotic Bcl-2 expression and up-regulation of proapoptotic Bax expression. We also confirmed that inhibition of LSD1 can sensitize the anti-tumor effect of DOX in vivo. CONCLUSION: Our findings suggest that the LSD1 inhibitor GSK-LSD1 has a weak inhibitory effect on the viability and cell cycle of GC cells, but can enhance the sensitivity of DOX.

6-Heterocyclic carboxylic ester derivatives of gliotoxin lead to LSD1 inhibitors in gastric cancer cells.

Gliotoxin is a representative compound of the epipolythiodioxopiperazine (ETP) class of fungal metabolites. Histone Lysine Specific Demethylase 1 (LSD1) is highly expressed in a variety of cancers. Herein, a series of 6-heterocyclic carboxylic ester derivatives of gliotoxin was designed and synthesized as new LSD1 inhibitors and their biological evaluations in human gastric MGC-803 and HGC-27 cells were carried out. All of the derivatives effectively suppressed the enzymatic activities of LSD1. In particular, compound 4e exhibited excellent LSD1 inhibition with IC50 = 62.40 nM, as well as anti-proliferation against MGC-803 and HGC-27 cells with IC50 values of 0.31 µM and 0.29 µM, respectively. 4e also had a remarkable capacity to inhibit the colony formation, suppress migration and induce the apoptosis of these two cancer cell lines. In sum, our findings identified and characterized the 6-heterocyclic carboxylic ester derivatives of gliotoxin as potent and cellular active LSD1 inhibitors, which may provide a novel chemotype of LSD1 inhibitors for gastric cancer treatment.

Generation, secretion and degradation of cancer immunotherapy target PD-L1.

Cancer immunotherapy is a rapidly developing and effective method for the treatment of a variety of malignancies in recent years. As a significant immune checkpoint, programmed cell death 1 ligand 1 (PD-L1) and its receptor programmed cell death protein 1 (PD-1) play the most significant role in cancer immune escape and cancer immunotherapy. Though PD-L1 have become an important target for drug development and there have been various approved drugs and clinic trials targeting it, and various clinical response rate and adverse reactions prevent many patients from benefiting from it. In recent years, combination trials have become the main direction of PD-1/PD-L1 antibodies development. Here, we summarized PD-L1 biofunctions and key roles in various cancers along with the development of PD-L1 inhibitors. The regulators that are involved in controlling PD-L1 expression including post-translational modification, mRNA level regulation as well as degradation and exosome secretory pathway of PD-L1 were focused. This systematic summary may provide comprehensive understanding of different regulations on PD-L1 as well as a broad prospect for the search of the important regulator of PD-L1. The regulatory factors of PD-L1 can be potential targets for immunotherapy and increase strategies of immunotherapy in combination.

Metabolomics study based on GC-MS reveals a protective function of luteolin against glutamate-induced PC12 cell injury.

Oxidative stress response is closely related to neurodegenerative diseases. This study aimed to investigate the cytoprotective effects of luteolin on glutamate-induced oxidative stress injury in PC12 cells. GC-MS combined with multivariate statistical approaches was used to perform metabolomics studies to assess the possible mechanisms. Our results identified 23 metabolites as differential expressed metabolites in the glutamate group, including cysteine content in cells that decreased drastically. This suggests that glutathione synthesis, which balances the redox state of cells, was affected. Luteolin inhibits the reduction in viability in glutamate-induced PC12 cells and regulates 13 differential expressed metabolites in glutamate-induced cell damage. These metabolites associated with luteolin included glycine, serine, and threonine metabolism; glyoxylate and dicarboxylate metabolism; aminoacyl-tRNA biosynthesis; cysteine and methionine metabolism; inositol phosphate metabolism; and starch and sucrose metabolism. In summary, the systemic antioxidant capacity of luteolin in PC12 cells is related to its regulation of amino acid, glucose, and nucleotide metabolism pathways.

LSD1-Based Reversible Inhibitors Virtual Screening and Binding Mechanism Computational Study.

As one of the crucial targets of epigenetics, histone lysine-specific demethylase 1 (LSD1) is significant in the occurrence and development of various tumors. Although several irreversible covalent LSD1 inhibitors have entered clinical trials, the large size and polarity of the FAD-binding pocket and undesired toxicity have focused interest on developing reversible LSD1 inhibitors. In this study, targeting the substrate-binding pocket of LSD1, structure-based and ligand-based virtual screenings were adopted to expand the potential novel structures with molecular docking and pharmacophore model strategies, respectively. Through drug-likeness evaluation, ADMET screening, molecular dynamics simulations, and binding free energy screening, we screened out one and four hit compounds from the databases of 2,029,554 compounds, respectively. Generally, these hit compounds can be divided into two categories, amide (Lig2 and Comp2) and 1,2,4-triazolo-4,3-α-quinazoline (Comp3, Comp4, Comp7). Among them, Comp4 exhibits the strongest binding affinity. Finally, the binding mechanisms of the hit compounds were further calculated in detail by the residue free energy decomposition. It was found that van der Waals interactions contribute most to the binding, and FAD is also helpful in stabilizing the binding and avoiding off-target effects. We believe this work not only provides a solid theoretical foundation for the design of LSD1 substrate reversible inhibitors, but also expands the diversity of parent nucleus, offering new insights for synthetic chemists.

Improved Thermal and Chemical Stability of Oxynitride Phosphor from Facile Chemical Synthesis for Vehicle Cornering Lights.

Orange Eu2+ -doped phosphors are essential for light-emitting diodes for cornering lights to prevent fatal road accidents at night, but such phosphors require features of high thermal, chemical stability and facile synthesis. This study reports a series of yellow-orange-red emitting SrAl2 Si3 ON6 :Eu2+ oxynitride phosphors, derived from the SrAlSi4 N7 nitride iso-structure by replacing Si4+ -N3- with Al3+ -O2- . The introduction of a certain amount of oxygen enabled the facile synthesis under atmospheric pressure using the air-stable raw materials SrCO3 , Eu2 O3 , AlN and Si3 N4 . SrAl2 Si3 ON6 has a smaller band gap and lower structure rigidity than SrAlSi4 N7 (5.19 eV vs 5.50 eV, Debye temperature 719 K vs 760 K), but exhibits higher thermal stability with 100 % of room temperature intensity remaining at 150 °C compared to 85 % for SrAlSi4 N7 . Electron paramagnetic resonance, thermoluminescence and density functional theory revealed that the oxygen vacancy electron traps compensated the thermal loss. Additionally, no decrease in emission intensity was found after either being heated at 500 °C for 2 hours or being immersed in water for 20 days, implying both of the thermal and chemical stability of SrAl2 Si3 ON6 :Eu2+ phosphors. The strategy of oxynitride-introduction from nitride promotes the development of low-cost thermally and chemically stable luminescent materials.

LSD1 deletion decreases exosomal PD-L1 and restores T-cell response in gastric cancer.

BACKGROUND: Histone lysine-specific demethylase 1 (LSD1) expression has been shown to be significantly elevated in gastric cancer (GC) and may be associated with the proliferation and metastasis of GC. It has been reported that LSD1 repressed tumor immunity through programmed cell death 1 ligand 1 (PD-L1) in melanoma and breast cancer. The role of LSD1 in the immune microenvironment of GC is unknown. METHODS: Expression LSD1 and PD-L1 in GC patients was analyzed by immunohistochemical (IHC) and Western blotting. Exosomes were isolated from the culture medium of GC cells using an ultracentrifugation method and characterized by transmission electronic microscopy (TEM), nanoparticle tracking analysis (NTA), sucrose gradient centrifugation, and Western blotting. The role of exosomal PD-L1 in T-cell dysfunction was assessed by flow cytometry, T-cell killing and enzyme-linked immunosorbent assay (ELISA). RESULTS: Through in vivo exploration, mouse forestomach carcinoma (MFC) cells with LSD1 knockout (KO) showed significantly slow growth in 615 mice than T-cell-deficient BALB/c nude mice. Meanwhile, in GC specimens, expression of LSD1 was negatively correlated with that of CD8 and positively correlated with that of PD-L1. Further study showed that LSD1 inhibited the response of T cells in the microenvironment of GC by inducing the accumulation of PD-L1 in exosomes, while the membrane PD-L1 stayed constant in GC cells. Using exosomes as vehicles, LSD1 also obstructed T-cell response of other cancer cells while LSD1 deletion rescued T-cell function. It was found that while relying on the existence of LSD1 in donor cells, exosomes can regulate MFC cells proliferation with distinct roles depending on exosomal PD-L1-mediated T-cell immunity in vivo. CONCLUSION: LSD1 deletion decreases exosomal PD-L1 and restores T-cell response in GC; this finding indicates a new mechanism with which LSD1 may regulate cancer immunity in GC and provides a new target for immunotherapy against GC.

Integrated Photovoltaic Charging and Energy Storage Systems: Mechanism, Optimization, and Future.

As an emerging solar energy utilization technology, solar redox batteries (SPRBs) combine the superior advantages of photoelectrochemical (PEC) devices and redox batteries and are considered as alternative candidates for large-scale solar energy capture, conversion, and storage. In this review, a systematic summary from three aspects, including: dye sensitizers, PEC properties, and photoelectronic integrated systems, based on the characteristics of rechargeable batteries and the advantages of photovoltaic technology, is presented. The matching problem of high-performance dye sensitizers, strategies to improve the performance of photoelectrode PEC, and the working mechanism and structure design of multienergy photoelectronic integrated devices are mainly introduced and analyzed. In particular, the devices and improvement strategies of high-performance electrode materials are analyzed from the perspective of different photoelectronic integrated devices (liquid-based and solid-state-based). Finally, future perspectives are provided for further improving the performance of SPRBs. This work will open up new prospects for the development of high-efficiency photoelectronic integrated batteries.

Discovery and pharmacodynamic evaluation of the novel butene lactone derivative M355 against influenza A virus in vitro and in vivo.

A new series of butene lactone derivatives were designed according to an influenza neuraminidase target and their antiviral activities against H1N1 infection of Madin-Darby canine kidney cells were evaluated. Among them, a compound that was given the name M355 was identified as the most potent against H1N1 (EC50 = 14.7 µM) with low toxicity (CC50 = 538.13 µM). It also visibly reduced the virus-induced cytopathic effect. Time-of-addition analysis indicated that H1N1 was mostly suppressed by M355 at the late stage of its infectious cycle. M355 inhibited neuraminidase in a dose-dependent fashion to a similar extent as oseltamivir, which was also indicated by a computer modeling experiment. In a mouse model, lung lesions and virus load were reduced and the expression of nucleoprotein was moderated by M355. The enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction analyses revealed that the levels of interferon-γ, interferon regulatory factor-3, Toll-like receptor-3, tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, and IL-8 were downregulated in the M355-treated groups, whereas the levels of IL-10 and IL-13 were upregulated. Similarly, IgG was found to be increased in infected mice plasma. These results demonstrate that M355 inhibit the expression of H1N1 in both cellular and animal models. Thus, M355 has the potential to be effective in the treatment of influenza A virus infection.

The overview of Mitogen-activated extracellular signal-regulated kinase (MEK)-based dual inhibitor in the treatment of cancers.

Mitogen-activated extracellular signal-regulated kinase 1 and 2 (MEK1/2) are the critical components of the mitogen-activated protein kinase/extracellular signal-regulated kinase 1 and 2 (MAPK/ERK1/2) signaling pathway which is one of the well-characterized kinase cascades regulating cell proliferation, differentiation, growth, metabolism, survival and mobility both in normal and cancer cells. The aberrant activation of MAPK/ERK1/2 pathway is a hallmark of numerous human cancers, therefore targeting the components of this pathway to inhibit its dysregulation is a promising strategy for cancer treatment. Enormous efforts have been done in the development of MEK1/2 inhibitors and encouraging advancements have been made, including four inhibitors approved for clinical use. However, due to the multifactorial property of cancer and rapidly arising drug resistance, the clinical efficacy of these MEK1/2 inhibitors as monotherapy are far from ideal. Several alternative strategies have been developed to improve the limited clinical efficacy, including the dual inhibitor which is a single drug molecule able to simultaneously inhibit two targets. In this review, we first introduced the activation and function of the MAPK/ERK1/2 components and discussed the advantages of MEK1/2-based dual inhibitors compared with the single inhibitors and combination therapy in the treatment of cancers. Then, we overviewed the MEK1/2-based dual inhibitors for the treatment of cancers and highlighted the theoretical basis of concurrent inhibition of MEK1/2 and other targets for development of these dual inhibitors. Besides, the status and results of these dual inhibitors in both preclinical and clinical studies were also the focus of this review.