Discovery of Novel Small-Molecule Inhibitors of NF-κB Signaling with Antiinflammatory and Anticancer Properties

Novel NF-κB Inhibitor-Conjugated Pt(IV) Prodrug to Enable Cancer Therapy through ROS/ER Stress and Mitochondrial Dysfunction and Overcome Multidrug Resistance

Although cisplatin has been widely used for clinical purposes, its application is limited due to its obvious side effects. To mitigate the defects of cisplatin, here, six "multitarget prodrugs" were synthesized by linking cisplatin and NF-κB inhibitors. Notably, complex 9 demonstrated a 63-fold enhancement in the activity against A549/CDDP cells with lower toxicity toward normal LO2 cells compared to cisplatin. Additionally, complex 9 could effectively cause DNA damage, induce mitochondrial dysfunction, generate reactive oxygen species, and induce cell apoptosis through the mitochondrial pathway and ER stress. Remarkably, complex 9 effectively inhibited the NF-κB/MAPK signaling pathway and disrupted the PI3K/AKT signaling transduction. Importantly, complex 9 showed superior in vivo antitumor efficiency compared to cisplatin or the combination of cisplatin/4, without obvious systemic toxicity in A549 or A549/CDDP xenograft models. Our results demonstrated that the dual-acting mechanism endowed the complexes with high efficiency and low toxicity, which may represent an efficient strategy for cancer therapy.

Dual-targeting tumor cells hybrids derived from Pt(IV) species and NF-κB inhibitors enables cancer therapy through mitochondrial dysfunction and ER stress and overcomes cisplatin resistance

To ameliorate the defects including serious side effects and drug resistance of Pt(II) drugs (e.g., cisplatin and oxaliplatin), here a novel of "dual-prodrug" by containing Pt(II) drugs and NF-κB inhibitors were synthesized and characterized. Among them, Pt(IV) complex 11 exhibited better cytotoxic activity than other Pt(IV) complexes and the corresponding Pt(II) drugs, with IC50 values ranged from 0.31 to 0.91 μM, respectively, and also displayed low toxicity toward two normal cells HL-7702 and BEAS-2B. More importantly, complex 11 significantly reversed cisplatin resistance in A549/CDDP cells, indicating that complex 11 was able to overcome multidrug resistance. Following mechanism studies demonstrated that complex 11 significantly induced DNA damage and ROS generation, arrest the cell cycle at the G2/M stage, suppressed cell migration and intrusion, and induced cell apoptosis through activated ER stress and mitochondrial apoptosis pathway in A549 cells. Moreover, complex 11 effectively suppressed the IKKβ phosphorylation, IκBα phosphorylation and NF-κB p65 phosphorylation and nuclear translocation, leading to blocked the NF-κB signal pathway in A549 cells. In vivo tests showed that the inhibitory rate in the complex 11 reached 69.2 %, which was much higher than that of oxaliplatin (55.6 %), 1a (39.7 %) and the combination of oxaliplatin/1a (65.1 %), without causing loss in the body weight.

Discovery of Ibrutinib-based BTK PROTACs with in vivo anti-inflammatory efficacy by inhibiting NF-κB activation

As a critical upstream regulator of nuclear factor-κB (NF-κB) activation, Bruton's tyrosine kinase (BTK) has been identified to be an effective therapeutic target for the treatment of acute or chronic inflammatory diseases. Herein, we describe the design, synthesis and structure-activity-relationship analysis of a novel series of Ibrutinib-based BTK PROTACs by recruiting Cereblon (CRBN) ligase. Among them, compound 15 was identified as the most potent degrader with a DC50 of 3.18 nM, significantly better than the positive control MT802 (DC50 of 63.31 nM). Compound 15 could also degrade BTK protein in Lipopolysaccharide (LPS)-stimulated RAW264.7 cells, and suppress the mRNA expression and secretion of proinflammatory cytokines such as IL-1β and IL-6 by inhibiting NF-κB activation. Furthermore, compound 15 reduced inflammatory responses in a mouse zymosan-induced peritonitis (ZIP) model. Our findings demonstrated for the first time that targeting BTK degradation by PROTACs might be an alternative option for the treatment of inflammatory disorders, and compound 15 represents one of the most efficient BTK PROTACs (DC50 = 3.18 nM; Dmax = 99.90%; near 100% degradation at 8 h) reported so far and could serve as a lead compound for further investigation as an anti-inflammatory agent.

Anti-inflammatory activity of fluorine-substituted benzo[h]quinazoline-2-amine derivatives as NF-κB inhibitors

Excessive inflammation can cause loss of tissue or organ function, leading to a number of chronic diseases and sometimes even death. Traditional treatment strategies for inflammation have mainly involved steroidal and non-steroidal anti-inflammatory drugs, but both have increasingly prominent side effects. Nuclear factor kappa B (NF-κB) inhibitors with anti-inflammatory properties and low toxicity are a new therapeutic strategy for the treatment of inflammatory diseases. To obtain novel NF-κB inhibitors, a series of 3,4-dihydronaphthalen-1(2H)-one derivatives (DHNs 6a-s), 1,4,5,6-tetrahydrobenzo[h]quinazolin-2-amine derivatives (BQAs 7a-c) and 5,6-dihydrobenzo[h]quinazolin-2-amine derivatives (BQAs 8a-p) were designed and synthesized, and characterized by NMR and HRMS. By evaluating toxicity and anti-inflammatory properties, fluorine-substituted 8c showed more potential anti-inflammatory activity and lower toxicity. 8c significantly reduced the phosphorylation of IκBα and p65, thereby inhibiting the NF-κB signaling pathway. In addition, 8c markedly decreased reactive oxygen species (ROS) production and downregulated the expression of NOD-like receptor pyrin domain-containing protein 3 (NLRP3), apoptosis-associated speck-like protein containing a CARD (ASC) and cysteine aspartate protein hydrolase-1 (caspase-1). Therefore, compound 8c is expected to be a candidate compound for NF-κB inhibition and deserves further research and development.

Targeted Lymphoma Therapy Using a Gold Nanoframework-Based Drug Delivery System

Precision nanomedicine can be employed as an alternative to chemo- or radiotherapy to overcome challenges associated with the often narrow therapeutic window of traditional treatment approaches, while safely inducing effective, targeted antitumor responses. Herein, we report the formulation of a therapeutic nanocomposite comprising a hyaluronic acid (HA)-coated gold nanoframework (AuNF) delivery system and encapsulated IT848, a small molecule with potent antilymphoma and -myeloma properties that targets the transcriptional activity of nuclear factor kappa B (NF-κB). The porous AuNFs fabricated via a liposome-templated approach were loaded with IT848 and surface-functionalized with HA to formulate the nanotherapeutics that were able to efficiently deliver the payload with high specificity to myeloma and lymphoma cell lines in vitro. In vivo studies characterized biodistribution, pharmacokinetics, and safety of HA-AuNFs, and we demonstrated superior efficacy of HA-AuNF-formulated IT848 vs free IT848 in lymphoma mouse models. Both in vitro and in vivo results affirm that the AuNF system can be adopted for targeted cancer therapy, improving the drug safety profile, and enhancing its efficacy with minimal dosing. HA-AuNF-formulated IT848 therefore has strong potential for clinical translation.

Discovery of First-in-Class TAK1-MKK3 Protein-Protein Interaction (PPI) Inhibitor for the Treatment of Ulcerative Colitis through Modulating TNF-α Production

Tumor necrosis factor α (TNF-α) has been demonstrated to be a therapeutic target for autoimmune diseases. However, this biological therapy exhibits some inevitable disadvantages, such as risk of infection. Thus, small-molecule alternatives by targeting TNF-α production signaling pathway are still in demand. Herein, we describe the design, synthesis, and structure-activity relationships of 3-aryindanone compounds regarding their modulation of TNF-α production. Among them, (R)-STU104 exhibited the most potent inhibitory activity on TNF-α production, which suppressed the TAK1/MKK3/p38/MnK1/MK2/elF4E signal pathways through binding with MKK3 and disrupting the TAK1 phosphorylating MKK3. As a result, (R)-STU104 demonstrated remarkable dose-effect relationships on both acute and chronic mouse UC models. In addition to its good pharmacokinetic (PK) and safety profile, (R)-STU104 showed better anti-UC efficacy in vivo at 10 mg/kg/d than mesalazine at the dose of 50 mg/kg/d. These results suggested that TAK1-MKK3 interaction inhibitors could be potentially utilized for the treatment of UC.

Design, synthesis, and biological evaluation of potent 1,2,3,4-tetrahydroisoquinoline derivatives as anticancer agents targeting NF-κB signaling pathway

The multifunctional transcription factor, nuclear factor-κB (NF-κB), is broadly involved in multiple human diseases, such as cancer and chronic inflammation, through abnormal modulations of the NF-κB signaling cascades. In patients with several types of cancer diseases, NF-κB is excessively activated, which could result in the stimulation of proliferation and/or suppression of apoptosis. Herein, we present a new series of 1,2,3,4-tetrahydroisoquinoline derivatives with good anticancer activities against various human cancer cell lines, which are rationally designed based on our novel NF-κB inhibitors. The SAR studies demonstrated that compound 5d with a methoxy group at the R₃ position exhibits the most anti-proliferative activity with GI₅₀ values, ranging 1.591 to 2.281 μM. Similar to KL-1156, the compound 5d (HSR1304) blocked NF-κB nuclear translocation step in LPS-stimulated MDA-MB-231 cells, probably leading to cytotoxic potency against tumor cells. Together with known potent NF-κB inhibitors containing diverse core heterocyclic moieties, the 1,2,3,4-tetrahydroisoquinoline derivatives can provide structural diversity, enhancing a potential for the development of a novel class of anticancer drugs.

Crystal structure and anti-inflammatory activity of (E)-7-fluoro-2-((5-methoxypyridin-3-yl)methylene)-3,4-dihydronaphthalen-1(2H)-one, C17H14FNO2

C17H14FNO2, monoclinic, C2/c (no. 15), a = 15.5754(12) Å, b = 7.4828(6) Å, c = 23.0981(18) Å, β = 90.797(7)°, V = 2691.8(4) Å3, Z = 8, R gt (F) = 0.0442, wR ref (F 2) = 0.1096, T = 100(1)° K.

Trifluoromethyl-substituted 3,5-bis(arylidene)-4-piperidones as potential anti-hepatoma and anti-inflammation agents by inhibiting NF-кB activation

Some methoxy-, hydroxyl-, pyridyl-, or fluoro-substituted 3,5-bis(arylidene)-4-piperidones (BAPs) could reduce inflammation and promote hepatoma cell apoptosis by inhibiting activation of NF-κB, especially after introduction of trifluoromethyl. Herein, a series of trifluoromethyl-substituted BAPs (4-30) were synthesised and the biological activities were evaluated. We successfully found the most potential 16, which contains three trifluoromethyl substituents and exhibits the best anti-tumour and anti-inflammatory activities. Preliminary mechanism research revealed that 16 could promote HepG2 cell apoptosis in a dose-dependent manner by down-regulating the expression of Bcl-2 and up-regulating the expression of Bax, C-caspase-3. Meanwhile, 16 inhibited activation of NF-κB by directly inhibiting the phosphorylation of p65 and IκBα induced by LPS, together with indirectly inhibiting MAPK pathway, thereby exhibiting both anti-hepatoma and anti-inflammatory activities. Molecular docking confirmed that 16 could bind to the active sites of Bcl-2, p65, and p38 reasonably. The above results suggested that 16 has enormous potential to be developed as a multifunctional agent for the clinical treatment of liver cancers and inflammatory diseases.

Modulation of the Innate Immune Response by Targeting Toll-like Receptors: A Perspective on Their Agonists and Antagonists

Toll-like receptors (TLRs) are a class of proteins that recognize pathogen-associated molecular patterns (PAMPs) and damaged-associated molecular patterns (DAMPs), and they are involved in the regulation of innate immune system. These transmembrane receptors, localized at the cellular or endosomal membrane, trigger inflammatory processes through either myeloid differentiation primary response 88 (MyD88) or TIR-domain-containing adapter-inducing interferon-β (TRIF) signaling pathways. In the last decades, extensive research has been performed on TLR modulators and their therapeutic implication under several pathological conditions, spanning from infections to cancer, from metabolic disorders to neurodegeneration and autoimmune diseases. This Perspective will highlight the recent discoveries in this field, emphasizing the role of TLRs in different diseases and the therapeutic effect of their natural and synthetic modulators, and it will discuss insights for the future exploitation of TLR modulators in human health.

Discovery of novel NF-кB inhibitor based on scaffold hopping: 1,4,5,6,7,8-hexahydropyrido[4,3-d]pyrimidine

NF-κB is a key signaling pathway molecule linking hepatoma and chronic inflammation. Inhibition of NF-κB activation can alleviate inflammation, and promote hepatoma cell apoptosis. In this study, a series of fluoro-substituted 1,4,5,6,7,8-hexahydropyrido[4,3-d]pyrimidines (PPMs, 31-57) were synthesized from 3,5-bis(arylidene)-4-piperidones (BAPs, 4-30) based on scaffold hopping. We successfully discovered the most potent 43 substituted by electron-withdrawing substitutes (3-F and 4-CF₃) exhibited less toxicity and higher anti-inflammatory activity. Preliminary mechanistic studies revealed that 43 induced dose-dependent cell apoptosis at cell and protein level, while inhibited NF-κB activation by suppressing LPS-induced phosphorylation levels of p65, IκBα and Akt, and by indirectly suppressing MAPK signaling, and by inhibiting the nuclear translocation of NF-κB induced by TNF-α or LPS. Docking analysis verified simulated 43 could reasonably bind to the active site of Bcl-2, p65 and p38 proteins. This compound, as a novel NF-κB inhibitor, also demonstrated both anti-inflammatory and anti-hepatoma activities, warranting its further development as a potential multifunctional agent for the clinical treatment of liver cancers and inflammatory diseases.

N-Alkyl-2-[4-(trifluoromethyl)benzoyl]hydrazine-1-carboxamides and Their Analogues: Synthesis and Multitarget Biological Activity

Based on the isosterism concept, we have designed and synthesized homologous N-alkyl-2-[4-(trifluoromethyl)benzoyl]hydrazine-1-carboxamides (from C₁ to C₁₈) as potential antimicrobial agents and enzyme inhibitors. They were obtained from 4-(trifluoromethyl)benzohydrazide by three synthetic approaches and characterized by spectral methods. The derivatives were screened for their inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) via Ellman’s method. All the hydrazinecarboxamides revealed a moderate inhibition of both AChE and BuChE, with IC₅₀ values of 27.04–106.75 µM and 58.01–277.48 µM, respectively. Some compounds exhibited lower IC₅₀ for AChE than the clinically used drug rivastigmine. N-Tridecyl/pentadecyl-2-[4-(trifluoromethyl)benzoyl]hydrazine-1-carboxamides were identified as the most potent and selective inhibitors of AChE. For inhibition of BuChE, alkyl chain lengths from C₅ to C₇ are optimal substituents. Based on molecular docking study, the compounds may work as non-covalent inhibitors that are placed in a close proximity to the active site triad. The compounds were evaluated against Mycobacterium tuberculosis H₃₇Rv and nontuberculous mycobacteria (M. avium, M. kansasii). Reflecting these results, we prepared additional analogues of the most active carboxamide (n-hexyl derivative 2f). N-Hexyl-5-[4-(trifluoromethyl)phenyl]-1,3,4-oxadiazol-2-amine (4) exhibited the lowest minimum inhibitory concentrations within this study (MIC ≥ 62.5 µM), however, this activity is mild. All the compounds avoided cytostatic properties on two eukaryotic cell lines (HepG2, MonoMac6).

Crystal structure and anti-inflammatory activity of (3E,5E)-3,5-bis(4-fluorobenzylidene)-1-((4-fluorophenyl)sulfonyl)piperidin-4-one-dichloromethane (1/1), C26H20Cl2F3NO3S

C26H20Cl2F3NO3S, triclinic, P1̄ (no. 2), a = 8.5616(4) Å, b = 11.6052(6) Å, c = 14.1451(8) Å, α = 66.617(6)°, β = 82.391(4)°, γ = 69.072(4)°, V = 1204.85(12) Å3, Z = 2, R gt(F) = 0.0460, wR ref(F 2) = 0.1206, T = 100.00(10) K.

Transcription Factor Inhibition: Lessons Learned and Emerging Targets

Transcription factors have roles at focal points in signaling pathways, controlling many normal cellular processes, such as cell growth and proliferation, metabolism, apoptosis, immune responses, and differentiation. Their activity is frequently deregulated in disease and targeting this class of proteins is a major focus of interest. However, the structural disorder and lack of binding pockets have made design of small molecules for transcription factors challenging. Here, we review some of the most recent developments for small molecule inhibitors of transcription factors emphasized in James Darnell's vision 17 years ago. We also discuss the progress so far on transcription factors recently nominated by genome-scale loss-of-function screens from the cancer dependency map project.

Crystal structure and anti-inflammatory activity of (3E,5E)-1-((4-chlorophenyl)sulfonyl)-3-(pyridin-4-ylmethylene)-5-(2-(trifluoromethyl)benzylidene)piperidin-4-one, C25H18ClF3N2O3S

C25H18ClF3N2O3S, monoclinic, P21/n (no. 14), a = 9.9087(5) Å, b = 21.7843(10) Å, c = 10.2512(6) Å, β = 94.749(5)°, V = 2205.2(2) Å3, Z = 4, R gt(F) = 0.0448, wR ref(F 2) = 0.1028, T = 100 K.

Crystal structure and anti-inflammatory activity of (3E,5E)-3-(2-fluorobenzylidene)-1-((4-acetamidophenyl)sulfonyl)-5-(pyridin-3-ylmethylene)piperidin-4-one-methanol-hydrate (2/1/1), C53H50F2N6O10S2

C53H50F2N6O10S2, monoclinic, P21/n (no. 14), a = 15.088(5) Å, b = 23.560(9) Å, c = 15.401(6) Å, β = 112.254(5)°, V = 5067(3) Å3, Z = 4, R gt(F) = 0.0509, wR ref(F 2) = 0.1336, T = 298(2) K.

Potential multifunctional agents with anti-hepatoma and anti-inflammation properties by inhibiting NF-кB activation

Inhibition of NF-κB signalling has been demonstrated as a therapeutic option in treating inflammatory diseases and cancers. Herein, we synthesized novel dissymmetric 3,5-bis(arylidene)-4-piperidones (BAPs, 83-102) and characterized fully. MTT and ELISA assay were performed to screen the anti-hepatoma and anti-inflammation properties. 96 showed the most potential bioactivity. 96 could promote HepG2 apoptosis through up-regulating the expression of C-Caspase-3 and Bax, down-regulating the expression of Bcl-2, while markedly inhibit LPS or TNF-α-induced activation of NF-κB through both inhibiting the phosphorylation of IκBα and p65, and preventing the p65 nuclear translocation to exhibit both anti-hepatoma and anti-inflammatory activities. Molecular docking verified that simulated 96 can effectively bond to the active site of Bcl-2 and NF-κB/p65 proteins. 96 inhibited xenografts growth by reducing the expression of TNF-α and Bcl-2 in the tumour tissue. This study suggested that 96 could be developed as a potential multifunctional agent for treatment of inflammatory diseases and cancers.

Jietacins, azoxy natural products, as novel NF-κB inhibitors: Discovery, synthesis, biological activity, and mode of action

Deregulation of NF-κB plays an important role in various diseases by controlling cell growth, inflammation, the immune response, and cytokine production. Although many NF-κB inhibitors have been developed, to the best of our knowledge, none of them have been successfully translated into clinical practice as medicines. To overcome this issue, we aimed to develop a new class of NF-κB inhibitors. Previous reports indicated that the N-terminal cysteine is a promising target for NF-κB. Based on this, we first selected 10 natural products or their derivatives from the natural product library that we developed and examined the effect on NF-κB and the viability of cancer cells with constitutively strong NF-κB activity. Among them, we found that an azoxy natural product, jietacin A, with a vinylazoxy group and an aliphatic side chain, reduced cell viability and inhibited nuclear translocation of free NF-κB. In addition, we performed design, synthesis, and biological evaluation of jietacin derivatives for development of a novel NF-κB inhibitor. Of these derivatives, a fully synthesized derivative 25 with vinylazoxy and ynone groups had a potent effect. We clarified the structure-activity relationship of this compound. Jietacin A and 25 also inhibited tumor necrosis factor-α-mediated induction of NF-κB. The NF-κB inhibitory effect depended on the N-terminal cysteine and the neighboring Arg-Ser-Ala-Gly-Ser-Ile (RSAGSI) domain of NF-κB. We also found that 25 inhibited the association between NF-κB and importin α, suggesting inhibition of NF-κB at an early step of nuclear translocation. Overall, this study indicated that the vinylazoxy motif may compose a new class of NF-κB inhibitors, providing further insight for rational drug design and rendering a unique mode of action.