Use of ent-montelukast or derivatives thereof in the preparation of a medicament for the treatment of a disease targeting TMEM164

Abstract

The application belongs to the technical field of biological medicine, and relates to application of ENT-montelukast or a derivative thereof in preparation of a drug for treating a disease with TMEM164 as a target. The application is verified by surface plasmon resonance technology (SPR) screening, and it is proved that the derivative such as ENT-montelukast or a salt thereof can strongly bind to TMEM164 protein; after biological verification, it is indicated that a TMEM164 overexpression cell line treated by the derivative such as ENT-montelukast or a salt thereof is significantly and effectively improved in sensitivity to ferroptosis. It is indicated that the derivative such as ENT-montelukast or a salt thereof has selective inhibition on TMEM164, and then a technical scheme of application of ENT-montelukast or a derivative thereof in preparation of a drug for treating a disease with TMEM164 as a target is proposed. The scheme provided by the application provides a new way for disease treatment targeting TMEM164.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology and relates to the use of ENT-montelukast or its derivatives in the preparation of drugs for treating diseases targeting TMEM164. Background Technology

[0002] Phospholipids are not only a protective barrier against harsh environments but also a hub for signal and substance exchange. Imbalances in lipid metabolism can lead to metabolic diseases such as obesity, fatty liver, tumors, and atherosclerosis. Lipid diversity and the LAND cycle are mediated by phospholipases (PLAs). 1 / 2 S and lysophosphatidylacyltransferase (LPLAT) are involved in the deacylation and reacylation of fatty acid chains, a process known as phospholipid remodeling. Phospholipid remodeling is closely related to development, disease progression, and treatment prognosis. Currently, there is still limited research on how phospholipids remodel phospholipids to manipulate cell fate. LPLATs (divided into the AGPAT and MBOAT families) have been widely reported to participate in phospholipid remodeling and thus alter cell fate (such as ferroptosis resistance). A key characteristic of LPLATs is their use of acyl-CoA as an acyl donor to catalyze acyl transfer reactions.

[0003] In 2023, Benjamin F. Cravatt and J. Fernando Bazan's laboratory published an article in Nature Chemical Biology detailing that TMEM164 can act as an acyltransferase, directly using C20:4-PC instead of acyl-CoA as a substrate to generate ferroptosis C20:4-ePL in multiple tumor cell lines. This means that TMEM164 has the function of promoting ferroptosis under normal physiological conditions.

[0004] Currently, very little is known about the functionality of TMEM164. Tao Fan's case report showed abnormal activation of TMEM164 in patients with lung adenocarcinoma (Fan, T., Liu, Y., Liu, H., Wang, L., Tian, ​​H., Zheng, Y., ... He, J. (2022). Transmembrane Protein-Based Risk Model and H3K4me3 Modification Characteristics in Lung Adenocarcinoma. Front Oncol, 12, 828814.). Furthermore, Masashi Nishikawa reported that TMEM164 promotes the progression of liver cancer (Nishikawa, M., Okada, H., Kawaguchi, K., Shimakami, T., Nio, K., Arai, K., ... Honda, M. (2023). Identification of a Transmembrane Protein Involved in Shear Stress Signaling and Hepatocarcinogenesis After a Sustained Virological Response to Hepatitis CVirus. Cell Mol Gastroenterol Hepatol, 16(2), 263-286.). However, Zhou Haibo's laboratory has shown that overexpression of TMEM164 in the field of neurodegeneration can inhibit astrocyte activation and protect neurons (Zhang, L., Jia, Z., Wu, Q., Bai, T., Wang, B., Hu, X., ... Zhou, H. (2023). Alleviating symptoms of neurodegenerative disorders by astrocyte-specific overexpression of TMEM164 in mice. Nat Metab, 5(10), 1787-1802.). How TMEM164, as an acyltransferase, mechanistically acquires tissue specificity under abnormal activation is not yet clear. Perturbations (often upregulation) of TMEM164 expression levels mediate various physiological and pathological progressions such as neurodegenerative diseases, autophagy, and tumorigenesis. To date, there is no direct and effective small molecule targeted inhibition of TMEM164 in existing technologies. Summary of the Invention

[0005] Given the lack of a direct and effective small molecule targeted inhibition scheme for TMEM164 in the existing technology, this invention provides the application of ENT-montelukast or its derivatives in the preparation of drugs targeting TMEM164 for diseases.

[0006] Specifically, this invention has found that S-configuration montelukast ENT-montelukast or its salt derivatives (ENT-montelukast or its salt derivatives) can be used as a selective inhibitor of TMEM164. Based on this, this application provides the use of ENT-montelukast or its derivatives in the preparation of drugs for treating diseases targeting TMEM164.

[0007] Diseases targeting TMEM164 include neurodegenerative diseases, tumors, and aging. Specifically, TMEM164 is related to autophagy, an evolutionarily conserved process involving the transport of damaged organelles, misfolded proteins, and other macromolecules to lysosomes for degradation and reuse via lysosomal mechanisms. Autophagy can occur in cells throughout the body, and diseases closely related to autophagy include neurodegenerative diseases, tumors, and aging.

[0008] More specifically, this application study found that selective inhibitors of TMEM164 can be used as therapeutic agents for TMEM164-mediated diseases (especially tumors associated with helper ferroptosis), and this application study found that ENT-montelukast or its derivatives have a strong affinity for TMEM164 and can increase the sensitivity of TMEM164-overexpressing cell lines to ferroptosis.

[0009] Based on this, this application provides the use of ENT-montelukast or its derivatives in the preparation of a medicament for treating diseases targeting TMEM164.

[0010] The objective of this invention is achieved through the following technical solution:

[0011] This invention first provides the use of ENT-montelukast or its derivatives in the preparation of medicaments for treating diseases targeting TMEM164.

[0012] Furthermore, this invention provides the use of ENT-montelukast or its derivatives in the preparation of TMEM164-targeting inhibitors. Specifically, the TMEM164-targeting inhibitors of this invention can directly function as drugs to specifically treat diseases targeting TMEM164.

[0013] In one embodiment of the present invention, the disease targeting TMEM164 refers to a neurodegenerative disease.

[0014] In one embodiment of the present invention, the disease targeting TMEM164 refers to phospholipid metabolism-related diseases.

[0015] In one embodiment of the present invention, the disease targeting TMEM164 refers to a tumor.

[0016] In one embodiment of the present invention, the disease targeting TMEM164 refers to lung adenocarcinoma.

[0017] In one embodiment of the present invention, the disease targeting TMEM164 refers to liver cancer.

[0018] In a more specific embodiment of the invention, ENT-montelukast or a derivative thereof is provided for use in the preparation of a medicament for use as an inducer of ferroptosis to treat tumors.

[0019] More specifically, the present invention provides the use of ENT-montelukast or its derivatives in the preparation of medicaments for use as ferroptosis inducers to treat lung adenocarcinoma or liver cancer.

[0020] Specifically, TMEM164 intervention in lipid metabolism induces ferroptosis resistance in cells, and treatment with ENT-montelukast or its derivatives can significantly improve the sensitivity of TMEM164-overexpressing cell lines to ferroptosis inducers.

[0021] In one embodiment of the present invention, the ENT-montelukast or its derivatives are used in the preparation of a medicament for treating diseases targeting TMEM164 by inhibiting the lipid metabolism mediated by TMEM164 protein.

[0022] The chemical formula of ENT-montelukast described in this invention is C 35 H 36 C l NO4S, with the structure shown in Formula 1, has three branches. One branch contains a carboxyl group, which readily forms a polar contact with proteins; the other two branches contain aromatic rings, which can form pi-pi valence-donating bonds or pi-cation stacks with adjacent amino acid residues. The biological function of ENT-montelukast remains unclear.

[0023]

[0024] In one embodiment of the present invention, the ENT-montelukast derivative includes a salt of ENT-montelukast, an enantiomer of ENT-montelukast, an enantiomer of a salt of ENT-montelukast, or an ENT-montelukast impurity derivative containing impurities. Preferably, the ENT-montelukast derivative is sodium ENT-montelukast.

[0025] More preferably, the ENT-montelukast derivative is selected from the following structures:

[0026]

[0027] This study found that both deletion and overexpression of TMEM164 conferred resistance to ferroptosis in cells, and overexpression of TMEM164 in tumor cell lines also triggered lipid metabolism disorders. The results further demonstrate that TMEM164 is a membrane lipid remodeling agent that controls ferroptosis.

[0028] This application proposes a crystal structure-matched ENT-montelukast or its derivatives that can be used as a selective inhibitor to inhibit the lipoacyl transfer activity of the TMEM164 protease.

[0029] Specifically, based on the crystal structure of TMEM164, this application investigated and analyzed the key active centers in its coordination pocket, and through bioverification, identified the key amino acid residues within the pocket that enable TMEM164 to function (specifically, the ion coordination centers formed by His181, Glu106, and Tyr177 stabilize the phospholipid substrate; secondly, the deprotonated thiol group of Cys123 attacks the ester bond at sn-2 of the phospholipid substrate, forming an intermediate product and releasing the byproduct lysophospholipid. Next, another lysophospholipid substrate enters the pocket and is stabilized by metal ions; His181 deprotonates the hydroxyl group at sn-2 of the lysophospholipid substrate. Finally, the resulting hydroxyl group directly attacks the thioester bond of the fatty acyl group -Cys123 formed in the intermediate state, generating the final product. Furthermore, the steric hindrance formed by G155 and F162 determines the specificity of the lipid substrate. When these sites mutate to alanine, TMEM164 loses its function).

[0030] Furthermore, this application further identified and tested 22 candidate inhibitors (TMEM164i) for TMEM164 through virtual screening and rational design. The specific methods were as follows: 1. First, a batch of small molecules without antitumor activity (all reported and patented) were screened, and then small molecules that could significantly improve the ferroptosis sensitivity of the TMEM164 OE cell line were selected; 2. These known small molecules were structurally modified to improve their affinity for TMEM164. Based on this, 11 high-scoring derivatives were selected through virtual docking scoring. Subsequently, through molecular interaction evaluation methods such as surface ion resonance (SPR), ENT-montelukast or its derivative (ENT-Montelukast sodium salt) showed a strong binding affinity for TMEM164 (mM-level molecular affinity). Finally, the CCK-8 cell viability assay was used to evaluate the effect of ENT-montelukast or its derivatives on improving the sensitivity of TMEM164 OE cell line to ferroptosis, and it was ultimately determined that ENT-montelukast or its derivatives were more effective than montelukast.

[0031] ENT-montelukast or its derivatives can occupy the active site of TMEM164, forming polar contacts or valence-donating bonds with key amino acid residues at the active site, thereby inhibiting the TMEM164-mediated acyl transfer reaction. Further studies have found that ENT-montelukast or its derivatives bind strongly to TMEM164 through ionic interactions and van der Waals forces.

[0032] In SPR experiments, ENT-montelukast or its salts and derivatives showed a four-order-of-magnitude higher affinity for TMEM164 than montelukast. Furthermore, CCK-8 activity assays confirmed that ENT-montelukast or its salts and derivatives significantly promoted TMEM164 OE ferroptosis more effectively than montelukast. This application utilizes ENT-montelukast or its salts and derivatives as a small-molecule inhibitor of TMEM164 acyltransferase. This study confirms that ENT-montelukast or its derivatives bind to TMEM164, thereby occupying its active pocket and inhibiting the enzyme-catalyzed acylation reaction.

[0033] Compared with the prior art, the advantages of this application are reflected in the following aspects:

[0034] 1. This invention simulates the binding of ENT-montelukast or its salt derivatives with TMEM164 through virtual molecular docking. The results show that the carboxyl-containing branches of ENT-montelukast or its salt derivatives form salt bridges with positively charged residues and metal ions, and form polar contacts with the 162nd amino acid (F162) of TMEM164. The other two branches containing aromatic rings form pi-pi or pi-cation stacks (His220) with adjacent residues, thereby binding with the ion coordination catalytic pocket within TMEM164. Figure 4 ).

[0035] 2. This invention demonstrates, through CCK-8 cell viability assay, that ENT-montelukast or its salt derivatives can effectively enhance the sensitivity of TMEM164 overexpressing cell lines to the ferroptosis inducer RSL3, and that this effect is dose-dependent.

[0036] Based on this, the present invention proposes that ENT-montelukast or its salts and derivatives can be used as small molecule inhibitors of TMEM164, and are expected to improve the treatment effect and prognosis of tumor patients resistant to ferroptosis. Attached Figure Description

[0037] Figure 1 Screening for potential inhibitors of TMEM164.

[0038] Figure 2 SPR experiments were used to assess the molecular interaction affinity (Kb) between ENT-montelukast or its salt derivatives and TMEM164. D =5.52e-10M)

[0039] Figure 3 : Trend of cell viability in TMEM164 tumor cell lines co-treated with gradient concentrations of montelukast (blue), ENT-montelukast or its salt derivatives (red).

[0040] Figure 4 Docking results of ENT-montelukast or its salts and derivatives with the TMEM164 virtual molecule. Amino acid residues coordinating with the small molecule are marked in blue (Asn-237, His-220, Phe-162, Lys-110). Yellow dashed lines represent hydrogen bonds and polar contacts, purple represents salt bridges, and Pi-pi conjugation is represented by blue dashed lines. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0042] The small molecule ENT-montelukast sodium salt used in the following embodiments of the present invention was purchased from Aladdin, CAS No.: 190078-45-6. Its specific structure is as follows:

[0043]

[0044] Unless otherwise specified, the materials used in the following embodiments are commonly used chemical raw materials or biological materials in the art, and the operating methods not specifically described in the following embodiments are conventional methods in the art.

[0045] Example 1: Molecular affinity assessment of ENT-montelukast sodium salt with TMEM164

[0046] Experimental materials: CM5 chip, TMEM164 protein, pH 4.0 NaAc (Cytiva), NHS (Cytiva), EDC (Cytiva), Running buffer (Cytiva), ENT-montelukast sodium salt.

[0047] Experimental methods:

[0048] The experiment employed the CM5 chip amino-coupling method. 400 mM EDC and 100 mM NHS were added to the running buffer (10 mM HEPES, pH 7.4, 137 mM NaCl, 2.7 mM KCl, 0.05% P2O, 1% DMSO) at a flow rate of 10 μl / min for 600 seconds to activate the CM5 chip. (The chip surface is composed of carboxylated dextran. Diluting EDC and NHS in the buffer and slowly flowing them through the CM5 chip channels at a specific flow rate allows the carboxylated dextran to capture and bind proteins without compromising its chemical properties; this process is called chip activation.) To couple the target protein, TMEM164 was diluted to 10 μg / ml with 10 mM acetic acid solution (pH 4.0) and flowed through the activated CM5 chip channels at a flow rate of 10 μl / min for 300 seconds. The CM5 chip at this point was designated CM5-TMEM164.

[0049] Then, the CM5-TMEM164 coupling was blocked with 1M ethanolamine at a flow rate of 10 μl / min for 600 seconds. The candidate small molecule (montelukast-modified derivative) was serially diluted from 20 μM to 0.156 μM using run buffer (10 mM HEPES, pH 7.4, 137 mM NaCl, 2.7 mM KCl, 0.05% P2O, 1% DMSO). Multiple cycles of kinetic measurements were performed at a flow rate of 30 μl / min (the surface ion resonance assay is a refined operation experiment; specifically, after creating the methodology on SPR software and placing the small molecule reagent in the designated clip, the instrument will aspirate the reagent according to the set program to pass it through the microchannels on the CM5 chip; only parameters need to be entered on the computer and the reagent placed, after which the instrument will collect data), each cycle for 180 seconds, followed by 180 seconds of dissociation, and then the next cycle was performed to obtain the kinetic affinity data of the TMEM164 protein. The obtained data were analyzed using Biacore Insight Evaluation software (V2.0.15.12933), and a 1:1 model was used for dynamic fitting.

[0050] The results showed that ENT-montelukast sodium salt had a strong affinity for TMEM164 (Table 1-40728). Figure 2 ).

[0051] Table 1. Affinity results of montelukast structurally modified derivatives with TMEM164 protein.

[0052]

[0053]

[0054]

[0055] In Table 1, K D It is the dissociation constant; the smaller the value, the stronger the affinity with the protein.

[0056] Experimental results show that ENT-montelukast sodium has great potential as a TMEM164 inhibitor.

[0057] Example 2: Evaluation of the ferroptosis-promoting effect of TMEM164 candidate inhibitors using the CCK-8 method

[0058] Experimental materials: human fibrosarcoma cell lines (HT1080, ATCC, CCL-121), 15% FBS medium, polyethyleneimine (PEI), Opti-MEM, human embryonic kidney cells (HEK293T), cell viability assay kit (CCK-8), RSA selective death inducer (RSL3), deferoxamine mesylate (DFOM), TMEM164i candidate molecular library (MCE, HY-LD-000005176), ENT-montelukast sodium (Aladdin), etc.

[0059] Experimental methods:

[0060] The culture medium formulation used in this experimental protocol is: 15% FBS diluted in high-glucose DMEM basic, with the addition of 1% NEAA and 1% Glutamax. This culture, referred to below as 15% FBS medium, was used in all experiments in this embodiment.

[0061] Virus packaging:

[0062] The overexpression vectors such as TMEM164, which package viruses, all use calcium phosphate transfection.

[0063] HEK293T was used at 2×10 6 Cells were seeded at a density of 15% FBS medium on 6-well plates (with 80% confluence after adhesion). After incubation in a 5% CO2, 37°C incubator for 16 hours, cell morphology was observed. Once the cell morphology was confirmed to be correct, the medium was replaced with fresh conventional medium (10% FBS, DMEM).

[0064] Before transfection, observe cell morphology and adhesion under a microscope to ensure the cells are in normal condition and free from contamination. Replace the medium with fresh (15% FBS, DMEM), adding 1.5 mL of medium to each 6-well plate and 3 mL to each 6 cm plate. Calculate the amount of plasmid and calcium transfer reagent used for transfection.

[0065] In this embodiment, the amount of plasmid used for transfection in a 6-well plate is 2 μg, and in a 6 cm plate it is 8 μg. Prepare the calcium phosphate transfection mixture. First add water, then add the required plasmids, including the plasmid containing the target gene (the plasmid containing the puro element) and the packaging plasmid (psPAPX2, PMD.2G). Add 2M calcium chloride to the mixture and mix by pipetting 15 times. Then add 2×HBS and vigorously pipet 30 times. When aspirating the liquid in this step, the pipette tip should be as deep as possible into the liquid surface, and care should be taken not to aspirate backwards. After mixing, let stand for 5 min. The 6-well plate mixture system is: DNA 4 μg (2 μg PKD-TMEM164 / EGFP-IRES2-PURO plasmid + 1.2 μg psPAPX2 + 0.8 μg PMD.2G), 2M CaCl2 31.25 μL, 2×HBS 250 μL, and add water to bring the volume to 500 μL. Add the resulting mixture dropwise to the culture dishes, ensuring each area is covered, and gently shake to mix. Observe the surface of the culture medium under a microscope for small black particles; these particles are calcium phosphate precipitates formed by plasmid formation. Their presence indicates normal operation. Replace the culture medium with fresh medium 15 hours after transfection and continue culturing in an incubator. The virus can be harvested 48 hours after transfection for subsequent infection.

[0066] In this embodiment, the conventional stable overexpression method relies on lentiviral infection, where psPAPX2 and PMD.2G are packaging plasmids. After transfection into cells, they express viral glycosylcoating to encapsulate the target gene for cell infection.

[0067] Lentiviral infection of HT1080 cells: Virus collected for 48 hours was mixed with HT1080 cell culture medium at a 1:1 ratio, and 8 μg / mL of polybrene was added to infect HT1080 cells inoculated for 16 hours. After 10 hours of treatment, the culture medium was replaced with fresh medium, and after 48 hours, puromycin (an aminoglycoside antibiotic produced by Streptomyces niger) was added for continuous selection for 72 hours.

[0068] TMEM164 candidate inhibitor (TMEM164i, see details) Figure 1 Screening of compounds: HT1080 was seeded into 96-well plates at a density of 5000 / well. After 24 h of adhesion, TMEM164i and 6 μM RSL3 were added at gradient concentrations and co-treated for 12 h (specifically, 6 μM RSL3 solution was prepared first with 15% FBS medium, and then 3 and 9 μM TMEM164i solutions were prepared with RSL3 solution respectively). Then, 10 μL of CCK-8 reagent was added to each well and incubated for 4 h. The absorbance value was detected at a wavelength of 450 nM.

[0069] Screening of montelukast-modified derivatives: HT1080 was seeded into 96-well plates at a density of 5000 / well. After 24 h of adhesion, gradient concentrations of ENT-montelukast sodium and 6 μM RSL3 were added for co-treatment for 12 h (specifically, 6 μM RSL3 solution was first prepared with 15% FBS medium, and then 0, 0.01, 0.1, 0.3, 1, 3, 9, and 27 μM TMEM164i solutions were prepared with RSL3 solution). Then, 10 μL of CCK-8 reagent was added to each well and incubated for 4 h. The absorbance value was detected at a wavelength of 450 nM.

[0070] The results showed that the TMEMi screening demonstrated that montelukast significantly increased the ferroptosis sensitivity of the TMEM164 OE cell line within this molecular library, and had no significant toxic (antitumor activity) effect on HT1080. Figure 1 Subsequently, montelukast was used as a lead compound for further modification. Eleven high-scoring derivatives were identified through virtual docking fitting scores (Table 1). Surface ion resonance experiments confirmed that ENT-montelukast sodium had the highest affinity for TMEM164 (Table 1, serial number 40728). ENT-montelukast sodium was selected for biovalidation. The results showed that, compared to R-montelukast, ENT-montelukast sodium (montelukast enantiomer S configuration) was more effective in promoting the sensitivity of the TMEM164 OE cell line to ferroptosis. Figure 3 ).

[0071] The above experiments demonstrate that ENT-montelukast or its salt derivatives can effectively inhibit the activity of TMEM164 protein and inhibit the enzymatic lipoacyl transfer function of TMEM164.

[0072] As described in the background section, Tao Fan's case report showed abnormal activation of TMEM164 in patients with lung adenocarcinoma (Fan,T.,Liu,Y.,Liu,H.,Wang,L.,Tian,H.,Zheng,Y.,...He,J.(2022).Transmembrane Protein-Based Risk Model and H3K4me3ModificationCharacteristics in Lung Adenocarcinoma.Front Oncol,12,828814.). Existing technology demonstrates that TMEM164 is significantly upregulated in patients with lung adenocarcinoma, and that TMEM164 affects the treatment and prognosis of lung adenocarcinoma. The experiments described in this application demonstrate that ENT-montelukast or its salt derivatives (especially compound 40728) can effectively inhibit the activity of TMEM164 protein. Therefore, based on the research in this application and existing technology in the field, it can be confirmed that ENT-montelukast or its salt derivatives (especially compound 40728) can be used to prepare drugs for the treatment of lung adenocarcinoma.

[0073] Masashi Nishikawa reported that TMEM164 promotes the progression of liver cancer (Nishikawa, M., Okada, H., Kawaguchi, K., Shimakami, T., Nio, K., Arai, K., ... Honda, M. (2023). Identification of a Transmembrane Protein Involved in Shear Stress Signaling and Hepatocarcinogenesis After a Sustained Virological Response to Hepatitis C Virus. Cell Mol Gastroenterol Hepatol, 16(2), 263-286.). TMEM164 was significantly upregulated in human liver cancer cells, and in vitro experiments verified that overexpression of TMEM164 promotes cancer progression. The experiments described in this application demonstrate that ENT-montelukast or its salts and derivatives (especially compound 40728) can effectively inhibit the activity of TMEM164 protein. Therefore, based on the research in this application and the prior art in this field, it can be confirmed that ENT-montelukast or its salts and derivatives (especially compound 40728) can be used to prepare drugs for treating liver cancer.

[0074] Therefore, the above embodiments of this application illustrate that ENT-montelukast or its salts and derivatives are expected to play a therapeutic role in inhibiting TMEM164-mediated diseases.

[0075] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. The use of ENT-montelukast or ENT-montelukast derivatives in the preparation of drugs for treating human fibrosarcoma overexpressing TMEM164, characterized in that, The ENT-montelukast or ENT-montelukast derivatives can reduce the viability of TMEM164-overexpressing human fibrosarcoma cells in the presence of the ferroptosis inducer RSL3. The ENT-montelukast derivatives are selected from the following structures: 。

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