Background/Objectives: Cancer persists as a leading concern in the current medical field, and current therapies are limited by toxicity, cost, and resistance. Targeted inhibition of tubulin polymerization is considered as a promising therapeutic strategy for cancer treatment. Methods: Thirty-one new tubulin polymerization inhibitors were designed via molecular hybridization techniques, and BLI technology was employed to quantitatively investigate their interactions with tubulin. Antiproliferative activities against MCF-7, MDA-MB-231, A549, and HeLa cell lines was evaluated using the CCK8 assay. Apoptosis induction and cell cycle arrest were analyzed by flow cytometry. The anti-tumor activity of compound B6 was validated in a mouse melanoma tumor model. Results: Compounds exhibited varying degrees of antiproliferative activity against four tumor cell lines. Among them, compound B6 was the most promising candidate and displayed strong broad-spectrum anticancer activity with an average IC50 value of 2 μM. The mechanism studies revealed that compound B6 inhibited tubulin polymerization in vitro, disrupted cell microtubule networks, and arrested the cell cycle at G2/M phase. Furthermore, B6 displayed significant in vivo antitumor efficacy in a melanoma tumor model with tumor growth inhibition rates of 70.21% (50 mg/kg). Conclusions: This work shows that B6 is a promising lead compound deserving further investigation as a potential anticancer agent.

RAF dimerization is crucial for oncogenic signaling in RAS mutant tumors, contributing to resistance to mitogen-activated protein kinase pathway inhibitors by promoting dysregulated BRAF dimerization. This makes it a promising target for overcoming resistance caused by paradoxical extracellular signal-regulated kinase (ERK) signaling activation resulting from BRAF mutations (e.g., BRAFV600E) and inhibitors like vemurafenib and dabrafenib. Peptide inhibitors such as Braftide (TRHVNILLFM) block BRAF dimerization but lack cell permeability and biological activity within cells. A promising solution is conjugating cell-penetrating peptides (CPPs). However, this approach involves a trade-off: it produces a larger molecule and increases the level of off-target cytotoxicity. On the basis of the crystal structure of the BRAF homodimer, we developed a series of linear and cyclic peptides derived from Braftide. Among these peptides, CBF-2-2 crosses the cell membrane without the aid of CPPs and significantly inhibits tumor cell growth, exhibiting greater serum stability than Braftide. Moreover, the composite peptide SCBF-2-2, which contains an anti-invasion sequence, disrupts BRAF dimers, effectively inhibits cancer cell proliferation and invasion, reduces ERK phosphorylation, and suppresses tumor growth in the A549 mouse xenograft model. SCBF-2-2 offers a new starting point for developing dual-function antitumor peptides that target the BRAF dimer.

Highly efficient synthesis of isoquinolones is achieved by a Rh(III)-catalyzed C-H activation/annulation of N-chlorobenzamide derivatives with alkynes. This transformation leverages the N-Cl moiety as a highly effective internal oxidant, enabling the reaction to proceed smoothly under mild conditions and delivering the target products in excellent yields (up to 98% yield). Control experiments further reveal the superior oxidizing ability of the N-Cl benzamide relative to its N-OMe and N-OPiv analogues. Notably, the reaction proceeds with 85% yield even at an exceptionally low catalyst loading of 0.05 mol %.

Novel carbamothioate-mediated sulfonyl fluoride synthesis enables chalcone functionalization without Michael addition side reactions.

Glycyrrhetinic acid (GA), a bioactive triterpenoid derived from Glycyrrhiza glabra, exhibits broad-spectrum antiviral properties but suffers from poor solubility and bioavailability. To enhance its anti-influenza activity, we designed and synthesized 12 novel nitrogen-containing heterocyclic GA derivatives through structural modifications at the A-ring (C-2/C-3) and C-30 position. All compounds were evaluated against influenza A/H1N1 virus in 293T cells. At 10 μM, 10 derivatives outperformed ribavirin, with compound 12b (bearing an A-ring furazan and C-30 imidazole ester) showing the highest potency (IC50 = 2.9 μM, selectivity index SI = 38.6) representing a 7.1-fold improvement over GA (IC50 = 9.6 μM) and 3.7-fold superiority to ribavirin. Molecular docking revealed that 12b binds strongly to neuraminidase (PDB:1NN2; binding energy: -8.11 kcal/mol) via hydrogen bonds with Glu413, Asp125, and Phe100, suggesting NA as a potential target. This study demonstrates that A-ring furazan modification combined with C-30 nitrogen-containing heterocyclic incorporation significantly enhances anti-influenza activity, providing a promising lead compound (12b) for further development.

As the incidence of ulcerative colitis (UC) has increased globally, there is a great unmet clinical need for efficacious, tolerable, and economical, orally administered drugs for its treatment. To help meet this need, we investigated anti-inflammatory small-molecule drugs with a novel structure, high activity, and high selectivity for the treatment of UC. Here, we designed and synthesized a series of novel anti-inflammatory compounds based on the molecular hybridization strategy by merging fragments from anti-inflammatory drugs. Among them, compound 11a best-exhibited lipopolysaccharide (LPS)-induced inflammation in RAW264.7 cells in vitro. Anti-inflammatory mechanism studies showed that compound 11a inhibited the release of pro-inflammatory cytokines and alleviated the inflammatory process by blocking the activation of the ASK1/p38 MAPKs/NF-κB signaling pathway in LPS-stimulated RAW264.7 cells. Analysis of the in vivo biological activity showed that compound 11a significantly alleviated dextran sodium sulfate-induced ulcerative colitis in mice while demonstrating an excellent safety in acute toxicity tests. Our study provides a novel compound for the treatment of UC that is worthy of further investigation and structural optimization.

Using virtual FragLites screening and a fragment-based drug discovery (FBDD) strategy, we designed and synthesized a series of 6-substituted-1-(3,4,5-trimethoxyphe-nyl)-1H-indole derivatives as potential tubulin polymerization inhibitors. Among them, compound 3g exhibited the best antiproliferative activity within this series and affected microtubule dynamics in a concentration-dependent manner. Further studies indicated that 3g induced G2/M cell-cycle arrest and triggered apoptosis in MCF-7 cells. In vivo, 3g achieved tumor growth inhibition rates of 23.3% and 44.2% at 20 mg/kg and 50 mg/kg, respectively, without evident systemic toxicity. These results suggest that 3g shows preliminary antitumor efficacy and may serve as a starting point for further mechanistic and structural studies. Further optimization and detailed pharmacokinetic and toxicity studies are merited to advance these inhibitors in preclinical development.

Smp43 is a natural antimicrobial peptide derived from scorpion venom containing 43 amino acids, which inhibits the proliferation of various cancer cells, providing a new surrogate for antitumor drug discovery. However, Smp43 is large (Mw: 4653 Da) and unstable as a linear peptide. We truncated Smp43 to identify the key fragment and found that Smp(1-14) displayed significant antitumor activity. Subsequent optimization of Smp(1-14) led to a series of stapled peptides, among which SSmp6 demonstrated enhanced antitumor activity, stability, and membrane permeability compared to the linear peptides. Moreover, SSmp6 could decrease the phosphorylation of AKT, damage cancer cell membranes, and induce cell apoptosis. The results highlight the potential of SSmp6 as a lead stapled peptide for developing novel antitumor therapies. The study introduces a concept for using antimicrobial peptides to develop anticancer drugs.

RAS-RAF interactions play a vital role in the RAS-RAF-MEK-ERK signaling pathway, significantly regulating cell proliferation, differentiation, and survival. Some small molecule inhibitors targeting various components of this pathway, such as MRTX849 and AMG 510, have been introduced for clinical application. However, peptide-based drugs encounter several challenges, such as poor cell permeability, low biological stability, and rapid in vivo clearance, which hinder their application. Herein, based on co-crystal complex structures and RAS-RAF interaction hotspots, we identified four linear peptides-Raf-0 to Raf-2 and CRD-0-derived from the α-helical regions of the RAS-binding domain (RBD) and the cysteine-rich domain (CRD) of CRAF. Raf-1 was selected for further modification using a hydrocarbon stapling strategy, capping it with stearic acid at the N-terminal due to its highest binding affinity in the SPR assay. As a result, Sraf-2-1 and Sraf-7-1 bound to KRASG12C with Kd values of 3.56 μM and 2.62 μM, respectively, demonstrating robust anticancer activity in the CCK8 assay. Additionally, Sraf-2-1 and Sraf-7-1 reduced AKT phosphorylation, induced cancer cell apoptosis in a concentration-dependent manner, and effectively inhibited cancer cell migration, showing improved α-helix stability and cell permeability. In summary, our findings indicate that the hydrocarbon stapling strategy and stearic acid tagging enhanced the therapeutic potential of peptide inhibitors, offering methods for targeting RAS in cancer therapy.

Cutaneous wound healing is a crucial biological process for tissue repair, with skin fibroblasts acting as key cellular mediators in this regenerative cascade. The TEAD family, a downstream effector of the Hippo signaling pathway, plays a crucial role in maintaining tissue homeostasis, regulating cell proliferation, and promoting organ growth. Inhibiting TEAD4-VGLL4 interactions can initiate tissue repair and regeneration. Peptides have been created to modulate PPIs with varying success. In particular, stapling peptides can improve their ability to penetrate cell membranes and their stability, showing high specificity and activity compared to linear peptides, which highlights their broad potential in drug development. Based on the crystal structure of the VGLL4-mTEAD4 complex, we designed and synthesized a series of stapled peptides derived from the key motif of the VGLL4 protein. Among these peptides, the stapled peptides SHip2-5 and SHip2-6 effectively bind to the mTEAD4 protein, promote the proliferation and migration of skin fibroblasts, upregulate the expression levels of YAP and its downstream target genes, and present high α-helical content, stability, and membrane permeability. Moreover, SHip2-5 and SHip2-6 promote skin wound healing in rats. As novel VGLL4-mTEAD4 stapled peptide inhibitors, SHip2-5 and SHip2-6 serve as lead compounds for effective skin wound treatment, providing a new perspective and theoretical basis for the functional regeneration of damaged skin tissues. It also demonstrates strong potential for application and significant research value.

In order to develop antifungal drugs, a series of novel azole analogues were designed and synthesized based on our previous work. Most of the target compounds had broad-spectrum antifungal activity, which showed excellent to moderate inhibitory activity against the tested strains, except A. fum 0504656. Among these, compounds B3, B7, B8, B11, B12 and E9 showed excellent activity against C. alb Y0109 and C. alb SC5314 (with the MIC80: 0.0156 ug/mL). In addition, compound B3 showed the best inhibitory activity against fluconazole-resistant strains C. alb 901 and C. alb 904, and had low toxicity against NIH/3T3 cells at the effective MIC range against fungi. Structure-activity relationship and docking studies of the derivatives suggest that the presence of the 2-fluoro-4-hydroxyphenyl and 1,2,3-triazole group enhance the antifungal activity of the compounds, which may be related to the interaction of the key groups with the amino acids surrounding the target enzyme.

Acute lung injury (ALI) is a serious public health problem associated with high morbidity and mortality. However, few efficacious drugs are clinically available. Inhibition of proinflammatory cytokines is considered to be a promising method for the treatment of inflammatory diseases. Herein, the total synthesis of a dibenzylbutane lignan, 9 '-O-di-(E)-feruloyl-meso-5,5 '-dimethoxysecoisolariciresinol (LCA), was completed. A series of LCA derivatives were designed and synthesized, and their anti-inflammatory activities were evaluated. Derivative 14r significantly inhibited LPS-induced expression of NO and the proinflammatory cytokines TNF-alpha, IL-6, and IL-1 beta in RAW 264.7 cells and inhibited activation of the NF-kappa B pathway. Compound 14r reduced LPS-induced pulmonary inflammation and ALI in mice. It showed significant protective effects against LPS-induced ALI in mice and significantly reduced levels of proinflammatory cytokines in serum and bronchoalveolar lavage fluid. The ratio of wet weight to dry weight of lung tissue was normalized by compound 14r, which was consistent with suppression of neutrophil infiltration and production of proinflammatory cytokines. Compound 14r reduced the mRNA expression of some proinflammatory cytokines, improved histopathologic changes, and reduced macrophage infiltration in lung tissues. Collectively, these results suggest a new series of LCA derivatives that could be promising anti-inflammatory agents for ALI treatment.

Directly blocking the Keap1-Nrf2 pathway is a promising strategy for the mitigation of acute lung injury (ALI). Peptide Keap1-Nrf2 inhibitors have been reported to have a high Keap1 binding affinity. However, these inhibitors showed weak activity in cells and/or animals. In this study, we designed a series of linear peptides from an Nrf2-based 9-mer Ac-LDEETGEFL-NH2. To improve the cellular activity, we further designed cyclic peptides based on the crystal complex of Keap1 with a linear peptide. Among them, cyclic 9-mer ZC9 targeting Keap1 showed a better affinity (K-D2 = 51 nM). Specifically, it exhibited an acceptable water solubility (>38 mg/mL), better cell permeability, cell activity, and metabolic stability (serum t( 1/2) > 24 h). In the in vitro LPS-induced oxidative damages and ALI model, ZC9 showed significant dose-response reversal activity without apparent toxicity. In conclusion, our results suggested ZC9 as a lead cyclic peptide targeting the Keap1-Nrf2 pathway for ALI clinical treatment.

Isocitrate dehydrogenase (IDH) is an enzyme that catalyses the oxidative decarboxylation of isocitrate, producing α-ketoglutarate (α-KG) relative to the hydroxylation of substrates. However, IDH mutants can further reduce α-KG to 2-hydroxyglutarate (2-HG) which competitively inhibits α-KG dependent enzymes, leading to the downregulation of normal hydroxylation pathways. Good IDH mutant inhibitors can effectively reduce the level of 2-HG and therefore disturb cellular malignant transformation. In this review, we introduce the biological functions of IDH, describe the tumorigenesis mechanisms of IDH variants, and review the structure-based drug discovery of clinical inhibitors during 2012-2024. We also find successful applications of covalent strategy in the development of irreversible IDH inhibitors. Biological screening methods are also collected in this paper, which may help researchers to rapidly construct workflows for drug discovery and development.

Halogens favorably contributes to the drug potency and metabolic stability via electrostatic interactions. Herein, the halogen effects on the reactivity of the halogenated 2,2,2-trifluoroacetophenones as serine-targeting covalent warheads were investigated. Our results showed that introducing halogen atoms, especially Cl or Br, into the phenyl scaffold would influence the electron density around the ring, which led to different time-dependent inhibition response to the target serine hydrolase (hCES1A). Co-crystallography analysis not only verified that halogenated molecules preferred to form covalent adducts, but also provided the conformational information for the design of covalent inhibitors targeting to hCES1A protein for the treatment of drug-induced acute enteritis.

Inflammation is the body's response to defence against infection or injury, and is associated with the progression of many diseases, such as inflammatory bowel disease (IBD) and rheumatoid arthritis (RA). LCA, a dibenzylbutane lignan extracted from the roots of traditional medicinal plant Litsea cubeba (Lour.) Pers., has demonstrated promising anti-inflammatory activity. In this study, a series of novel LCA derivatives were designed, synthesized, and evaluated for anti-inflammatory activity. Lipopolysaccharide (LPS)-induced RAW 264.7 cell model experiments showed that compound 10h (at 20 mu M of concentration) had the strongest inhibitory effect on NO release, and inhibited the secretion and gene expression levels of interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha in vitro. In addition, western blot, immunofluorescence, and molecular docking showed that the anti-inflammatory mechanism of compound 10h may be related to the nuclear factor (NF)-kappa B signalling pathway. In vivo studies based on a carrageenan-induced mouse paw edema model have shown significant anti-inflammatory activity of compound 10h at 20 mg kg-1. Preliminary in vitro and in vivo studies indicate that compound 10h has the potential to be developed as a novel anti-inflammatory agent. Compound 10h, a novel dibenzylbutane lignan LCA derivative, has potential anti-inflammatory activity by inhibiting NF-kappa B activation.

Metastasis is one of the major causes of death in patients with cancer, and cell invasion plays a fundamental part in this process. Because of the absence of efficacious treatments, caring for these patients is challenging. Recently, we optimized the structure of the naturally occurring lasso peptide sungsanpin. We identified two peptides, octapeptide S3 and cyclic peptide S4, which inhibited invasion into A549 cells effectively. We undertook an alanine scan of S3 to explore the structure-activity relationship. The linear octapeptide S3-4 and cyclic peptide S4-1 exhibited improved inhibition of invasion into A549 cells. We modified S3-4 to obtain S3-4K, which displayed much higher inhibitory activity against invasion into A549 cells than S3-4. Of all peptides tested, S4-1 upregulated significantly mRNA of tissue inhibitor matrix metalloproteinase TIMP-1 and TIMP-2.

The roots of Litsea cubeba (Lour.) Pers have been used for the treatment of rheumatism. We previously extracted and isolated the natural product dibenzylbutane lignan LCA with anti-inflammatory activity. In the current study, using LCA as the lead compound, two series of LCA derivatives with an imide structure and butadiene structure were designed and synthesized. Among them, compounds 10c and 16a showed stronger inhibitory effects on LPS-induced NO and ROS production in RAW264.7 cells. Further study showed that compound 16a not only reduced the levels of inflammatory cytokines, including IL-6, TNF-α, and IL-1β, but it also significantly reduced the expression of iNOS and COX-2. Preliminary mechanism of action studies suggested that 16a exerts anti-inflammatory effects by inhibiting the NF-κB signaling pathway. Overall, our results suggest that compound 16a may be used as a promising anti-inflammatory drug to enrich the compound library. Further study into compound 16a could provide research ideas and methods for developing anti-inflammatory drugs.

Correction for ‘Discovery of dibenzylbutane lignan LCA derivatives as potent anti-inflammatory agents’ by Zhen Wang et al. , RSC Med. Chem. , 2024, https://doi.org/10.1039/d4md00053f.