Anti-rheumatic property and physiological safety of KMU-11342 in in vitro and in vivo models.

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disorder characterized by joint destruction due to synovial hypertrophy and the infiltration of inflammatory cells. Despite substantial progress in RA treatment, challenges persist, including suboptimal treatment responses and adverse effects associated with current therapies. This study investigates the anti-rheumatic capabilities of the newly identified multi-protein kinase inhibitor, KMU-11342, aiming to develop innovative agents targeting RA. In this study, we synthesized the novel multi-protein kinase inhibitor KMU-11342, based on indolin-2-one. We assessed its cardiac electrophysiological safety using the Langendorff system in rat hearts and evaluated its toxicity in zebrafish in vivo. Additionally, we examined the anti-rheumatic effects of KMU-11342 on human rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS), THP-1 cells, and osteoclastogenesis in RAW264.7 cells. KMU-11342 demonstrated the ability to inhibit LPS-induced chemokine inhibition and the upregulation of pro-inflammatory cytokines, cyclooxygenase-2, inducible nitric oxide synthase, p-IKKα/ß, p-NF-κB p65, and the nuclear translocation of NF-κB p65 in RA-FLS. It effectively suppressed the upregulation of NLR family pyrin domain containing 3 (NLRP3) and caspase-1 cleavage. Furthermore, KMU-11342 hindered the activation of osteoclast differentiation factors such as RANKL-induced TRAP, cathepsin K, NFATc-1, and c-Fos in RAW264.7 cells. KMU-11342 mitigates LPS-mediated inflammatory responses in THP-1 cells by inhibiting the activation of NLRP3 inflammasome. Notably, KMU-11342 exhibited minimal cytotoxicity in vivo and electrophysiological cardiotoxicity ex vivo. Consequently, KMU-11342 holds promise for development as a therapeutic agent in RA treatment.

2-Thioxothiazolidin-4-one Analogs as Pan-PIM Kinase Inhibitors.

Proviral integration site for Moloney murine leukemia virus (PIM) kinases are proto-oncogenic kinases involved in the regulation of several cellular processes. PIM kinases are promising targets for new drug development because they play a major role in many cancer-specific pathways, such as survival, apoptosis, proliferation, cell cycle regulation, and migration. Here, 2-thioxothiazolidin-4-one derivatives were synthesized and evaluated as potent pan-PIM kinase inhibitors. Optimized compounds showed single-digit nanomolar IC50 values against all three PIM kinases with high selectivity over 14 other kinases. Compound 17 inhibited the growth of Molm-16 cell lines (EC50 = 14 nM) and modulated the expression of pBAD and p4EBP1 in a dose-dependent manner.

KMU-1170, a Novel Multi-Protein Kinase Inhibitor, Suppresses Inflammatory Signal Transduction in THP-1 Cells and Human Osteoarthritic Fibroblast-Like Synoviocytes by Suppressing Activation of NF-κB and NLRP3 Inflammasome Signaling Pathway.

Protein kinases regulate protein phosphorylation, which are involved in fundamental cellular processes such as inflammatory response. In this study, we discovered a novel multi-protein kinase inhibitor, KMU-1170, a derivative of indolin-2-one, and investigated the mechanisms of its inflammation-inhibiting signaling in both THP-1 cells and human osteoarthritic fibroblast-like synoviocytes (FLS). We demonstrated that in THP-1 cells, KMU-1170 inhibited lipopolysaccharide (LPS)-induced upregulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and, furthermore, suppressed LPS-induced phosphorylation of transforming growth factor-ß-activated kinase 1, JNK, ERK, inhibitor of NF-κB kinase α/ß (IKKα/ß), and NF-κB p65 as well as nuclear translocation of NF-κB p65. Moreover, KMU-1170 suppressed LPS-induced upregulation of proinflammatory cytokines such as IL-1ß, TNF-α, and IL-6, and, notably, inhibited LPS-induced upregulation of the NLRP3 inflammasome in THP-1 cells. Importantly, KMU-1170 attenuated LPS-mediated inflammatory responses in human osteoarthritic FLS, such as the upregulation of IL-1ß, TNF-α, IL-6, iNOS, and COX-2 and the phosphorylation of IKKα/ß and NF-κB p65. Collectively, these results suggest that KMU-1170 inhibits inflammatory signal transduction and could be developed as a potential anti-inflammatory agent.

Anti-Inflammatory Effects of the Novel PIM Kinase Inhibitor KMU-470 in RAW 264.7 Cells through the TLR4-NF-κB-NLRP3 Pathway.

PIM kinases, a small family of serine/threonine kinases, are important intermediates in the cytokine signaling pathway of inflammatory disease. In this study, we investigated whether the novel PIM kinase inhibitor KMU-470, a derivative of indolin-2-one, inhibits lipopolysaccharide (LPS)-induced inflammatory responses in RAW 264.7 cells. We demonstrated that KMU-470 suppressed the production of nitric oxide and inducible nitric oxide synthases that are induced by LPS in RAW 264.7 cells. Furthermore, KMU-470 inhibited LPS-induced up-regulation of TLR4 and MyD88, as well as the phosphorylation of IκB kinase and NF-κB in RAW 264.7 cells. Additionally, KMU-470 suppressed LPS-induced up-regulation at the transcriptional level of various pro-inflammatory cytokines such as IL-1ß, TNF-α, and IL-6. Notably, KMU-470 inhibited LPS-induced up-regulation of a major component of the inflammasome complex, NLRP3, in RAW 264.7 cells. Importantly, PIM-1 siRNA transfection attenuated up-regulation of NLRP3 and pro-IL-1ß in LPS-treated RAW 264.7 cells. Taken together, these findings indicate that PIM-1 plays a key role in inflammatory signaling and that KMU-470 is a potential anti-inflammatory agent.

Meridianin C inhibits the growth of YD-10B human tongue cancer cells through macropinocytosis and the down-regulation of Dickkopf-related protein-3.

Meridianin C is a marine natural product known for its anti-cancer activity. At present, the anti-tumour effects of meridianin C on oral squamous cell carcinoma are unknown. Here, we investigated the effect of meridianin C on the proliferation of four different human tongue cancer cells, YD-8, YD-10B, YD-38 and HSC-3. Among the cells tested, meridianin C most strongly reduced the growth of YD-10B cells; the most aggressive and tumorigenic of the cell lines tested. Strikingly, meridianin C induced a significant accumulation of macropinosomes in the YD-10B cells; confirmed by the microscopic and TEM analysis as well as the entry of FITC-dextran, which was sensitive to the macropinocytosis inhibitor amiloride. SEM data also revealed abundant long and thin membrane extensions that resemble lamellipodia on the surface of YD-10B cells treated with meridianin C, pointing out that meridianin C-induced macropinosomes was the result of macropinocytosis. In addition, meridianin C reduced cellular levels of Dickkopf-related protein-3 (DKK-3), a known negative regulator of macropinocytosis. A role for DKK-3 in regulating macropinocytosis in the YD-10B cells was confirmed by siRNA knockdown of endogenous DKK-3, which led to a partial accumulation of vacuoles and a reduction in cell proliferation, and by exogenous DKK-3 overexpression, which resulted in a considerable inhibition of the meridianin C-induced vacuole formation and decrease in cell survival. In summary, this is the first study reporting meridianin C has novel anti-proliferative effects via macropinocytosis in the highly tumorigenic YD-10B cell line and the effects are mediated in part through down-regulation of DKK-3.

Discovery of biaryls as RORγ inverse agonists by using structure-based design.

RORγ plays a critical role in controlling a pro-inflammatory gene expression program in several lymphocyte lineages including T cells, γδ T cells, and innate lymphoid cells. RORγ-mediated inflammation has been linked to susceptibility to Crohn's disease, arthritis, and psoriasis. Thus inverse agonists of RORγ have the potential of modulating inflammation. Our goal was to optimize two RORγ inverse agonists: T0901317 from literature and 1 that we obtained from internal screening. We used information from internal X-ray structures to design two libraries that led to a new biaryl series.

Discovery of biaryl carboxylamides as potent RORγ inverse agonists.

RORγt is a pivotal regulator of a pro-inflammatory gene expression program implicated in the pathology of several major human immune-mediated diseases. Evidence from mouse models demonstrates that genetic or pharmacological inhibition of RORγ activity can block the production of pathogenic cytokines, including IL-17, and convey therapeutic benefit. We have identified and developed a biaryl-carboxylamide series of RORγ inverse agonists via a structure based design approach. Co-crystal structures of compounds 16 and 48 supported the design approach and confirmed the key interactions with RORγ protein; the hydrogen bonding with His479 was key to the significant improvement in inverse agonist effect. The results have shown this is a class of potent and selective RORγ inverse agonists, with demonstrated oral bioavailability in rodents.

Structure-based design of low-nanomolar PIM kinase inhibitors.

PIM kinases are implicated in variety of cancers by promoting cell survival and proliferation and are targets of interest for therapeutic intervention. We have identified a low-nanomolar pan-PIM inhibitor (PIM1/2/3 potency 5:14:2nM) using structure based modeling. The crystal structure of this compound with PIM1 confirmed the predicted binding mode and protein-ligand interactions except those in the acidic ribose pocket. We show the SAR suggesting the importance of having a hydrogen bond donor in this pocket for inhibiting PIM2; however, this interaction is not important for inhibiting PIM1 or PIM3. In addition, we report the discovery of a new class of PIM inhibitors by using computational de novo design tool implemented in MOE software (Chemical Computing Group). These inhibitors have a different interaction profile.

Inhibition of adipogenesis and leptin production in 3T3-L1 adipocytes by a derivative of meridianin C.

Meridianin C, a marine alkaloid, is a potent protein kinase inhibitor and has anti-cancer activity. We have recently developed a series of meridianin C derivatives (compound 7a-7j) and reported their proviral integration Moloney Murine Leukemia Virus (pim) kinases' inhibitory and anti-proliferative effects on human leukemia cells. Here we investigated the effect of these meridianin C derivatives on adipogenesis. Strikingly, among the derivatives tested, compound 7b most strongly inhibited lipid accumulation during the differentiation of 3T3-L1 preadipocytes into adipocytes. However, meridianin C treatment was largely cytotoxic to 3T3-L1 adipocytes. On mechanistic levels, compound 7b reduced not only the expressions of CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), and fatty acid synthase (FAS) but also the phosphorylation levels of signal transducer and activator of transcription-3 (STAT-3) and STAT-5 during adipocyte differentiation. Moreover, compound 7b repressed leptin, but not adiponectin, expression during adipocyte differentiation. Collectively, these findings demonstrate that a meridianin C derivative inhibits adipogenesis by down-regulating expressions and/or phosphorylations of C/EBP-α, PPAR-γ, FAS, STAT-3 and STAT-5.

Synthesis and evaluation of 5-(3-(pyrazin-2-yl)benzylidene)thiazolidine-2,4-dione derivatives as pan-pim kinases inhibitors.

Pim kinases play a key role in the regulation of signaling pathways including proliferation, migration, and metabolism and are a potential target for cancer therapy. A series of 5-benzylidenethiazolidine-2,4-diones were synthesized as pim kinase inhibitors. The structure-activity relationships (SAR) of the analogues in inhibiting in vitro pim kinase activity as well as the proliferation of leukemia cell lines were examined. SAR studies indicated that a hydroxyl group at the 2-position of the benzene ring of 5-benzylidenethiazolidine-2,4-dione plays an important role in the inhibitory activity against all three pim kinases and replacement with a pyrazinyl group at the 5-position of the benzene ring of 5-benzylidenethiazolidine-2,4-dione improved activity significantly. The compounds exerted anti-proliferative activity against the three leukemia cell lines we tested. The most potent compound, 5i, had an EC50 value of 0.8 µM in the MV4-11 cell line. The result of kinase profiling indicated that compound 5i was highly selective for pim-kinases.

Synthesis and anti-proliferative activity evaluation of N3-acyl-N5-aryl-3,5-diaminoindazole analogues as anti-head and neck cancer agent.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is the 11th leading cancer by incidence worldwide. Surgery and radiotherapy have been the major treatment for patients with HNSCC while chemotherapy has become an important treatment option for locally advanced HNSCC. Understanding of the molecular mechanisms underlying HNSCC impelled the development of targeted therapeutic agents. The development and combinations of targeted therapies in different cellular pathways may be needed to fulfill the unmet needs of current HNSCC chemotherapy. RESULTS: A series of N3-acyl-N5-aryl-3,5-diaminoindazoles were synthesized and their anti-proliferative activities were evaluated against human cancer cell lines, Caki, A549, AMC-HN1, AMC-HN3, AMC-HN4, AMC-HN6, and SNU449. The cellular selectivity of compound was obtained by the modification of substituent at N5-aryl group of 3,5-diaminoindazole. Compound 9a and 9b showed more than 7-fold selectivity for AMC-HN4 and AMC-HN3, respectively. CONCLUSIONS: N3-acyl-N5-aryl-3,5-diaminoindazole analogues can be used as hits in the development of anticancer drug for HNSCC.

KMU-191 Induces Apoptosis in Human Clear Cell Renal Cell Carcinoma Caki Cells Through Modulation of Bcl-xL, Mcl-1 (L), c-FLIP (L), and p53 Proteins.

The anti-proliferative effects of a newly developed N3-acyl-N5-aryl-3,5-diaminoindazole analog, KMU-191, have been previously evaluated in various cancer cells. However, the detailed anti-cancer molecular mechanisms of KMU-191 remain unknown. In this study, we investigated anti-cancer mechanisms by which KMU-191 regulates apoptosis-related genes in human clear cell renal cell carcinoma Caki cells. KMU-191 induced poly ADP-ribose polymerase cleavage and caspase-dependent apoptosis. In addition, KMU-191 induced down-regulation of the long form of cellular FADD-like IL-1ß-converting enzyme inhibitory protein (c-FLIP (L)) at the transcriptional level as well as that of long form of myeloid cell leukemia (Mcl-1 (L)) and B-cell lymphoma-extra large at the post-transcriptional level. Furthermore, KMU-191-induced apoptosis was closely associated with the Mcl-1 (L) down-regulation, but also partially associated with c-FLIP (L) down-regulation. In contrast, KMU-191 up-regulated p53, which is closely related to KMU-191-induced apoptosis. Although KMU-191 showed cytotoxicity of normal cells, it unusually did not induce cardiotoxicity. Taken together, these results suggest that a multi-target small molecule, N3-acyl-N5-aryl-3,5-diaminoindazole analog, KMU-191 is a potential anti-cancer agent that does not induce cardiotoxicity.

Identification and Kinetic Characterization of Serum- and Glucocorticoid-Regulated Kinase Inhibitors Using a Fluorescence Polarization-Based Assay.

The serum- and glucocorticoid-regulated kinase (SGK) family consists of three isoforms (SGK1, SGK2, and SGK3) that have been implicated in the regulation of tumor growth, metastasis, autophagy, and epithelial ion transport. SGK1 and SGK3 play essential roles in protein kinase B (AKT or PKB)-independent phosphoinositide 3-kinases (PI3K)-mediated tumorigenesis, as evidenced by the significantly elevated expression levels of SGK1 and SGK3 in many cancers, including prostate cancer, colorectal carcinoma, estrogen-dependent breast cancer, and glioblastoma. Therefore, SGK is a potential target for anticancer therapy. A small kinase-focused library comprising 160 compounds was screened against SGK1 using a fluorescence polarization-based kinase assay that yielded a Z'-factor of 0.82. Among the 39 compounds obtained as initial hits in a primary screen, 12 compounds contained the thiazolidine-2,4-dione scaffold. The inhibitory mechanisms of the most potent hit, KMU010402, were further investigated using kinetic analyses, followed by determination of the inhibition constants for SGK1, SGK2, and SGK3. Molecular modeling was used to propose a potential binding mode of KMU010402 to SGK1.

Discovery of Potent Selective Nonzinc Binding Autotaxin Inhibitor BIO-32546.

Autotaxin (ATX) is a lysophospholipase D that is the main enzyme responsible for generating LPA in body fluids. Although ATX was isolated from a conditioned medium of melanoma cells, later it was discovered to play a critical role in vascular and neuronal development. ATX has also been implicated in primary brain tumor, fibrosis, and rheumatoid arthritis, as well as neurological diseases such as multiple sclerosis, Alzheimer's disease, and neuropathic pain. As ATX and LPA levels are increased upon neuronal injury, a selective ATX inhibitor could provide a new approach to treat neuropathic pain. Herein we describe the discovery of a novel series of nonzinc binding reversible ATX inhibitors, particularly a potent, selective, orally bioavailable, brain-penetrable tool compound BIO-32546, as well as its synthesis, X-ray cocrystal structure, pharmacokinetics, and in vivo efficacy.

Development and Application of a High-Throughput Fluorescence Polarization Assay to Target Pim Kinases.

Pim proteins consisting of three isoforms (Pim-1, Pim-2, and Pim-3) are a family of serine/threonine kinases that regulate fundamental cellular responses such as cell growth, differentiation, and apoptosis. Overexpression of the Pim kinases has been linked to a wide variety of hematological and solid tumors. Thus, all three Pim kinases have been studied as promising targets for anticancer therapy. Here, we report on the development and optimization of an immobilized metal ion affinity partitioning (IMAP) fluorescence polarization (FP) method for Pim kinases. In this homogeneous 384-well assay method, fluorescein-labeled phosphopeptides are captured on cationic nanoparticles through interactions with immobilized trivalent metals, resulting in high polarization values. The apparent Km values for adenosine triphosphate (ATP) were determined to be 45 ± 7, 6.4 ± 2, and 29 ± 5 µM for Pim-1, Pim-2, and Pim-3, respectively. The assay yielded robustness with Z'-factors of >0.75 and low day-to-day variability (CV <5%) for all three Pim kinases. The IMAP FP assay was further validated by determining IC50 values for staurosporine and a known Pim inhibitor. We have also used an IMAP FP assay to examine whether compound 1, an ATP mimetic inhibitor designed through structure-based drug design, is indeed an ATP-competitive inhibitor of Pim kinases. Kinetic analysis based on Lineweaver-Burk plots showed that the inhibition mechanism of compound 1 is ATP competitive against all three Pim isoforms. The optimized IMAP assay for Pim kinases not only allows for high-throughput screening but also facilitates the characterization of novel Pim inhibitors for drug development.

The novel anti-adipogenic effect and mechanisms of action of SGI-1776, a Pim-specific inhibitor, in 3T3-L1 adipocytes.

The proviral integration site for moloney murine leukemia virus (Pim) kinases, consisting of Pim-1, Pim-2 and Pim-3, belongs to a family of serine/threonine kinases that are involved in controlling cell growth and differentiation. Pim kinases are emerging as important mediators of adipocyte differentiation. SGI-1776, an inhibitor of Pim kinases, is widely used to assess the physiological roles of Pim kinases, particularly cell functions. In the present study, we examined the effects of SGI-1776 on adipogenesis. The anti­adipogenic effect of SGI­1776 was measured by Oil Red O staining and AdipoRed assays. The effect of SGI­1776 on the growth of 3T3­L1 adipocytes was determined by cell count analysis. The effects of SGI­1776 on the protein and mRNA expression of adipogenesis-related proteins and adipokines in 3T3­L1 adipocytes were also evaluated by western blot analysis and RT­PCR, respectively. Notably, SGI-1776 markedly inhibited lipid accumulation during the differentiation of 3T3-L1 preadipocytes into adipocytes. On a mechanistic level, SGI-1776 inhibited not only the expression of CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ) and fatty acid synthase (FAS), but also the phosphorylation of signal transducer and activator of transcription-3 (STAT-3). Moreover, SGI-1776 decreased the expression of adipokines, including the expression of leptin and regulated on activation, normal T cell expressed and secreted (RANTES) during adipocyte differentiation. These findings demonstrate that SGI-1776 inhibits adipogenesis by downregulating the expression and/or phosphorylation levels of C/EBP-α, PPAR-γ, FAS and STAT-3.

AMIGO2, a novel membrane anchor of PDK1, controls cell survival and angiogenesis via Akt activation.

The phosphoinositide 3-kinase-Akt signaling pathway is essential to many biological processes, including cell proliferation, survival, metabolism, and angiogenesis, under pathophysiological conditions. Although 3-phosphoinositide-dependent kinase 1 (PDK1) is a primary activator of Akt at the plasma membrane, the optimal activation mechanism remains unclear. We report that adhesion molecule with IgG-like domain 2 (AMIGO2) is a novel scaffold protein that regulates PDK1 membrane localization and Akt activation. Loss of AMIGO2 in endothelial cells (ECs) led to apoptosis and inhibition of angiogenesis with Akt inactivation. Amino acid residues 465-474 in AMIGO2 directly bind to the PDK1 pleckstrin homology domain. A synthetic peptide containing the AMIGO2 465-474 residues abrogated the AMIGO2-PDK1 interaction and Akt activation. Moreover, it effectively suppressed pathological angiogenesis in murine tumor and oxygen-induced retinopathy models. These results demonstrate that AMIGO2 is an important regulator of the PDK1-Akt pathway in ECs and suggest that interference of the PDK1-AMIGO2 interaction might be a novel pharmaceutical target for designing an Akt pathway inhibitor.

Antioxidant activity of 3,4,5-trihydroxyphenylacetamide derivatives.

A series of amide derivatives of 3,4,5-trihydroxyphenylacetic acid was synthesized in two steps. The antioxidant activities were evaluated by using four different in vitro models such as ABTS and DPPH radical scavenging activity and FTC and TBA anti-lipid peroxidation activity. Most of compounds were more powerful radical scavengers than vitamin C and were comparable to Trolox. It was found that there were no direct correlations between radical scavenging and anti-peroxidation activities. The inhibitory activity of compound on lipid peroxidation showed remarkable dependency on both the number of phenolic hydroxyl group and the length of methylene linker in N-arylalkyl group of amide. Compound 14, a conjugate of 3,4,5-trihydroxyphenylacetic acid and dopamine, was found as powerful antioxidant as propyl gallate in all four antioxidant assays.

Identification of KMU-3, a novel derivative of gallic acid, as an inhibitor of adipogenesis.

Differentiation of preadipocyte, also called adipogenesis, leads to the phenotype of mature adipocyte. Excessive adipogenesis, however, is largely linked to the development of obesity. Herein we investigated a library of 53 novel chemicals, generated from a number of polyphenolic natural compounds, on adipogenesis. Strikingly, among the chemicals tested, KMU-3, a derivative of gallic acid, strongly suppressed lipid accumulation during the differentiation of 3T3-L1 preadipocytes into adipocytes. On mechanistic levels, KMU-3 inhibited expressions of CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), and fatty acid synthase (FAS) during adipocyte differentiation. Moreover, KMU-3 reduced expressions of adipokines, including retinol binding protein-4 (RBP-4), leptin, and regulated on activation, normal T cell expressed and secreted (RANTES) during adipocyte differentiation. Of further note, KMU-3 rapidly blocked the phosphorylation of signal transducer and activator of transcription-3 (STAT-3) during the early stage of adipogenesis. Importantly, pharmacological inhibition studies revealed that AG490, a JAK-2/STAT-3 inhibitor suppressed adipogenesis and STAT-3 phosphorylation, implying that early blockage of STAT-3 activity is crucial for the KMU-3-mediated anti-adipogenesis. These findings demonstrate firstly that KMU-3 inhibits adipogenesis by down-regulating STAT-3, PPAR-γ, C/EBP-α, and FAS. This work shows that KMU-3 is an inhibitor of adipogenesis and thus may have therapeutic potential against obesity.