G Protein-Coupled Estrogen Receptor-Mediated Anti-Inflammatory and Mucosal Healing Activity of a Trimethylpyridinol Analogue in Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is characterized by abnormal immune responses, including elevated proinflammatory cytokines, such as tumor necrosis factor-α (TNFα) and interleukin-6 (IL-6) in the gastrointestinal (GI) tract. This study presents the synthesis and anti-inflammatory evaluation of 2,4,5-trimethylpyridin-3-ol analogues, which exhibit dual inhibition of TNFα- and IL-6-induced inflammation. Analysis using in silico methods, including 3D shape-based target identification, modeling, and docking, identified G protein-coupled estrogen receptor 1 (GPER) as the molecular target for the most effective analogue, 6-26, which exhibits remarkable efficacy in ameliorating inflammation and restoring colonic mucosal integrity. This was further validated by surface plasmon resonance (SPR) assay results, which showed direct binding to GPER, and by the results showing that GPER knockdown abolished the inhibitory effects of 6-26 on TNFα and IL-6 actions. Notably, 6-26 displayed no cytotoxicity, unlike G1 and G15, a well-known GPER agonist and an antagonist, respectively, which induced necroptosis independently of GPER. These findings suggest that the GPER-selective compound 6-26 holds promise as a therapeutic candidate for IBD.

Structure Confirmation of Dechlorotrichotoxin A through Stereoselective Total Synthesis.

The stereoselective total synthesis of dechlorotrichotoxin A, alongside the synthesis of a 1:1 10E/Z mixture of trichotoxin A, was successfully achieved, commencing from the natural monoterpenoid (-)-citronellal. Key steps in the synthesis involved introducing three alkenes and establishing a stereogenic secondary alcohol center. These transformations were accomplished through olefin cross-metathesis, Tebbe olefination, and enantioselective allylation using a chiral phosphoric acid. A comparison of the spectroscopic data between the synthetic dechlorotrichotoxin A and the reported spectra confirmed that the polyketide isolated from a Smenospongia species corresponds to trichotoxin A rather than dechlorotrichotoxin A.

Antitumor effect of 3-(quinolin-2-ylmethylene)-4,6-dimethyl-5-hydroxy-7-azaoxindole down-regulating the Gas6-Axl axis.

In this study, a new series of 3-arylidene-4,6-dimethyl-5-hydroxy-7-azaoxindole compounds with a wide range of functional groups were designed, synthesized, and evaluated for their antitumor activity. Among the 35 compounds, compound 6-15, with a quinoline moiety, showed cytotoxic IC50 values superior to those of sunitinib against the seven cancer cell lines (MCF-7, MDA-MB-231, HT-29, DU145, U937, A549, and PANC-1). However, its inhibitory activity against receptor tyrosine kinases (VEGFR2, PDGFRß, c-KIT, FGFR1, FLT3, CSF1R, EGFR, Axl, and Axl mutant) was 100 -3000-fold weaker than that of sunitinib. Interestingly, compound 6-15 exerted a 3.6-fold stronger cytotoxicity than sunitinib in the gemcitabine-resistant PANC-1 cell line and significantly inhibited Axl, which was in contrast with the effect of sunitinib. Nonetheless, both compounds suppressed the expression of growth arrest-specific 6 (Gas6), the ligand of Axl. The inhibitory effect of compound 6-15 on the Gas6-Axl axis was similar to that of Gas6 knockdown by siRNA in PANC-1 cells in terms of apoptosis induction, increase in Bax/Bcl-2 ratio, Axl down-regulation, and PI3K/Akt inhibition. The inhibitory effect of compound 6-15 on tumor growth in mouse tumor models with A549 and PANC-1 xenografts was much greater than that of cisplatin or gemcitabine. Taken together, the current findings demonstrate that compound 6-15 is a promising anticancer drug candidate that acts by inhibiting the Gas6-Axl axis.

Antitumor activity of a pexidartinib bioisostere inhibiting CSF1 production and CSF1R kinase activity in human hepatocellular carcinoma.

Macrophage colony-stimulating factor (M-CSF, also known as CSF1) in tumor tissues stimulates tumor growth and tumor-induced angiogenesis through an autocrine and paracrine action on CSF1 receptor (CSF1R). In the present study, novel bioisosteres of pexidartinib (1) were synthesized and evaluated their inhibitory activities against CSF1R kinase and tumor growth. Among newly synthesized bioisosteres, compound 3 showed the highest inhibition (95.1%) against CSF1R tyrosine kinase at a fixed concentration (1 µM). The half maximal inhibitory concentration (IC50) of pexidartinib (1) and compound 3 was 2.7 and 57.8 nM, respectively. Unlike pexidartinib (1), which cross-reacts to three targets with structural homology, such as CSF1R, c-KIT, and FLT3, compound 3 inhibited CSF1R, c-KIT, but not FLT3, indicating compound 3 may be a more selective CSF1R inhibitor than pexidartinib (1). The inhibitory effect of compound 3 on the proliferation of various cancer cell lines was the strongest in U937 cells followed by THP-1 cells. In the case of cancer cell lines derived from solid tumors, the anti-proliferative activity of compound 3 was weaker than pexidartinib (1), except for Hep3B. However, compound 3 was safer than pexidartinib (1) in terminally differentiated normal cells such as macrophages. Pexidartinib (1) and compound 3 suppressed the production of CSF1 in Hep3B liver cancer cells as well as in the co-culture of Hep3B cells and macrophages. Also, pexidartinib (1) and compound 3 decreased the population ratio of the M2/M1 phenotype and inhibited their migration. Importantly, compound 3 preferentially inhibited M2 phenotype over M1, and the effect was about 4 times greater than that of pexidartinib (1). In addition, compound 3 inhibited maintenance of cancer stem cell population. In a chick chorioallantoic membrane (CAM) tumor model implanted with Hep3B cells, tumor growth and tumor-induced angiogenesis were significantly blocked by compound 3 to a similar extent as pexidartinib (1). Overall, compound 3, a bioisostere of pexidartinib, is an effective dual inhibitor to block CSF1R kinase and CSF1 production, resulting in significant inhibition of tumor growth.

Combining NMR and MS to Describe Pyrrole-2-Carbaldehydes in Wheat Bran of Radiation.

Nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) are indispensable analytical tools to provide chemical fingerprints in metabolomics studies. The present study evaluated radiation breeding wheat lines for chemical changes by non-targeted NMR-based metabolomics analysis of bran extracts. Multivariate analysis following spectral binning suggested pyrrole-2-carbaldehydes as chemical markers of four mutant lines with distinct NMR fingerprints in a δH range of 9.28-9.40 ppm. Further NMR and MS data analysis, along with chromatographic fractionation and synthetic preparation, aimed at structure identification of marker metabolites and identified five pyrrole-2-carbaldehydes. Quantum-mechanical driven 1H iterative full spin analysis (QM-HiFSA) on synthetic pyrrole-2-carbaldehydes provided a precise description of complex peak patterns. Biological evaluation of pyrrole-2-carbaldehydes was performed with nine synthetic products, and six compounds showed hepatoprotective effects via modulation of reactive oxygen species production. Given that three out of five identified in wheat bran of radiation were described for hepatoprotective activity, the value of radiation mutation to greatly enhance pyrrole-2-carbaldehyde production was supported.

Synthesis of Pyridoxine-Derived Dimethylpyridinols Fused with Aminooxazole, Aminoimidazole, and Aminopyrrole.

Described in this paper are studies on the preparation of three classes of dimethylpyridinols derived from pyridoxine fused with aminooxazole, aminoimidazole, and aminopyrrole. The key feature of this synthetic strategy is the manipulation of hydroxymethyl moiety of C(5)-position of the pyridoxine starting material along with the installation of an amino group at C(6)-position. Efficient and practical synthesis for the oxazole- and imidazole-fused targets was accomplished, while the instability of the pyrrole-fused one was observed.

6-Amino-2,4,5-trimethylpyridin-3-ol and 2-amino-4,6-dimethylpyrimidin-5-ol derivatives as selective fibroblast growth factor receptor 4 inhibitors: design, synthesis, molecular docking, and anti-hepatocellular carcinoma efficacy evaluation.

A novel series of aminotrimethylpyridinol and aminodimethylpyrimidinol derivatives were designed and synthesised for FGFR4 inhibitors. Structure-activity relationship on the FGFR4 inhibitory activity of the new compounds was clearly elucidated by an intensive molecular docking study. Anti-cancer activity of the compounds was evaluated using hepatocellular carcinoma (HCC) cell lines and a chick chorioallantoic membrane (CAM) tumour model. Compound 6O showed FGFR4 inhibitory activity over FGFR1 - 3. Compared to the positive control BLU9931, compound 6O exhibited at least 8 times higher FGFR4 selectivity. Strong anti-proliferative activity of compound 6O was observed against Hep3B, an HCC cell line which was a much more sensitive cell line to BLU9931. In vivo anti-tumour activity of compound 6O against Hep3B-xenografted CAM tumour model was almost similar to BLU9931. Overall, compound 6O, a novel derivative of aminodimethylpyrimidinol, was a selective FGFR4 kinase inhibitor blocking HCC tumour growth.

Novel Pyridine Bioisostere of Cabozantinib as a Potent c-Met Kinase Inhibitor: Synthesis and Anti-Tumor Activity against Hepatocellular Carcinoma.

Two novel bioisosteres of cabozantinib, 3 and 4, were designed and synthesized. The benzene ring in the center of the cabozantinib structure was replaced by trimethylpyridine (3) and pyridine (4), respectively. Surprisingly, the two compounds showed extremely contrasting mesenchymal-epithelial transition factor (c-Met) inhibitory activities at 1 µM concentration (4% inhibition of 3 vs. 94% inhibition of 4). The IC50 value of compound 4 was 4.9 nM, similar to that of cabozantinib (5.4 nM). A ligand-based docking study suggested that 4 includes the preferred conformation for the binding to c-Met in the conformational ensemble, but 3 does not. The anti-proliferative activity of compound 4 against hepatocellular carcinoma (Hep3B and Huh7) and non-small-cell lung cancer (A549 and H1299) cell lines was better than that of cabozantinib, whereas 3 did not show a significant anti-proliferative activity. Moreover, the tumor selectivity of compound 4 toward hepatocellular carcinoma cell lines was higher than that of cabozantinib. In the xenograft chick tumor model, compound 4 inhibited Hep3B tumor growth to a much greater extent than cabozantinib. The present study suggests that compound 4 may be a good therapeutic candidate against hepatocellular carcinoma.

Synthesis and anti-hepatocellular carcinoma activity of aminopyridinol-sorafenib hybrids.

Sorafenib is recommended as the primary therapeutic drug for patients with hepatocellular carcinoma. To discover a new compound that avoids low response rates and toxic side effects that occur in sorafenib therapy, we designed and synthesized new hybrid compounds of sorafenib and 2,4,5-trimethylpyridin-3-ols. Compound 6 was selected as the best of 24 hybrids that inhibit each of the four Raf kinases. The anti-proliferative activity of 6 in HepG2, Hep3B, and Huh7 cell lines was slightly lower than that of sorafenib. However, in H6c7 and CCD841 normal epithelial cell lines, the cytotoxicity of 6 was much lower than that of sorafenib. In addition, similar to sorafenib, compound 6 inhibited spheroid forming ability of Hep3B cells in vitro and tumour growth in a xenograft tumour model of the chick chorioallantoic membrane implanted with Huh7 cells. Compound 6 may be a promising candidate targeting hepatocellular carcinoma with low toxic side effects on normal cells.

Synthesis and activity of N-(5-hydroxy-3,4,6-trimethylpyridin-2-yl)acetamide analogues as anticolitis agents via dual inhibition of TNF-α- and IL-6-induced cell adhesions.

Tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) are the critical pro-inflammatory cytokines involved in the pathogenesis of inflammatory bowel disease (IBD). Inhibition of these cytokines and related signaling pathways has been a target for the development of IBD therapeutics. In the current study, 6-acetamido-2,4,5-trimethylpyridin-3-ol (1) and various analogues with the amido scaffold were synthesized and examined for their inhibitory activities in in vitro and in vivo IBD models. The parent compound 1 (1 µM) showed an inhibitory activity against TNF-α- and IL-6-induced adhesion of monocytes to colon epithelial cells, which was similar to tofacitinib (1 µM), a JAK inhibitor, but much better than mesalazine (1,000 µM). All the analogues showed a positive relationship (R2 = 0.8943 in a linear regression model) between the inhibitory activities against TNF-α-induced and those against IL-6-induced adhesion. Compound 2-19 turned out to be the best analogue and showed much better inhibitory activity against TNF-α- and IL-6-induced adhesion of the cells than tofacitinib. In addition, oral administration of compound 1 and 2-19 resulted in a significant suppression of clinical signs of TNBS-induced rat colitis, including weight loss, colon tissue edema, and myeloperoxidase activity, a marker for inflammatory cell infiltration in colon tissues. More importantly, compound 2-19 (1 mg/kg) was more efficacious in ameliorating colitis than compound 1 and sulfasalazine (300 mg/kg), the commonly prescribed oral IBD drug. Taken together, the results suggest that compound 2-19 can be a novel platform for dual-acting IBD drug discovery targeting both TNF-α and IL-6 signaling.

Synthesis and anticancer evaluation of 6-azacyclonol-2,4,6-trimethylpyridin-3-ol derivatives: M3 muscarinic acetylcholine receptor-mediated anticancer activity of a cyclohexyl derivative in androgen-refractory prostate cancer.

We recently reported 2,4,5-trimethylpyridin-3-ol with C(6)-azacyclonol, whose code name is BJ-1207, showing a promising anticancer activity by inhibiting NOX-derived ROS in A549 human lung cancer cells. The present study was focused on structural modification of the azacyclonol moiety of BJ-1207 to find a compound with better anticancer activity. Ten new compounds (3A-3J) were prepared and evaluated their inhibitory actions against proliferation of eighteen cancer cell lines as a primary screening. Among the ten derivatives of BJ-1207, the effects of compounds 3A and 3J on DU145 and PC-3, androgen-refractory cancer cell lines (ARPC), were greater than the parent compound, and compound 3A showed better activity than 3J. Antitumor activity of compound 3A was also observed in DU145-xenografted chorioallantoic membrane (CAM) tumor model. In addition, the ligand-based target prediction and molecular docking study using DeepZema® server showed compound 3A was a ligand to M3 muscarinic acetylcholine receptor (M3R) which is overexpressed in ARPC. Carbachol, a muscarinic receptor agonist, concentration dependently increased proliferation of DU145 in the absence of serum, and it also activated NADPH oxidase (NOX). The carbachol-induced proliferation and NOX activity was significantly blocked by compounds 3A in a concentration-dependent manner. This finding might become a new milestone in the development of pyridinol-based anti-cancer agents against ARPC.

Antioxidant Analogue 6-Amino-2,4,5-Trimethylpyridin-3-ol Ameliorates Experimental Colitis in Mice.

BACKGROUND: Oxidative stress has been suggested to be a factor contributing to the disease severity of inflammatory bowel disease (IBD). BJ-1108, a derivative of 6-amino-2,4,5-trimethylpyridin-3-ol, is reported to significantly inhibit the generation of reactive oxygen species (ROS) in vitro. However, whether this molecule affects intestinal inflammation is largely unknown. We aimed to investigate the effect of BJ-1108 on dextran sulfate sodium (DSS)-induced experimental colitis in mice. METHODS: Colitis was induced in mice with DSS, and disease severity was estimated by evaluating body weight, colon length, histology, immune cell infiltration, and intestinal permeability. We examined the protective effects of BJ-1108 on barrier function using Caco-2 cells. Last, we estimated the impact of BJ-1108 on the phosphorylation of NF-kB, PI3K/AKT, and mitogen-activated protein kinases. RESULTS: Mice treated with BJ-1108 exhibited improved disease severity, as indicated by evaluations of body weight, histological scores, spleen weight, and infiltrates of T cells and macrophages. The administration of BJ-1108 inhibited the colonic mRNA expression of IL-6 and IL-1ß in vivo. Additionally, BJ-1108 limited intestinal permeability and enhanced the expression of tight junction (TJ) proteins such as claudin-1 and claudin-3 in the DSS-induced colitis model. In an in vitro model using Caco-2 cells, BJ-1108 ameliorated cytokine-induced ROS generation in a dose-dependent manner and remarkably recovered barrier dysfunction as estimated by evaluating transepithelial electrical resistance and TJ protein expression. BJ-1108 suppressed the NF-kB/ERK/PI3K pathway. CONCLUSIONS: This study demonstrated that BJ-1108 ameliorated intestinal inflammation in an experimental colitis mouse model, suggesting possible therapeutic implications for IBD.

Inhibition of colitis by ring-modified analogues of 6-acetamido-2,4,5-trimethylpyridin-3-ol.

6-Aminopyridin-3-ol scaffold has shown an excellent anti-inflammatory bowel disease activity. Various analogues with the scaffold were synthesized in pursuit of the diversity of side chains tethering on the C(6)-position. Structure-activity relationship among the analogues was investigated to understand the effects of the side chains and their linkers on their anti-inflammatory activities. In this study, structural modification moved beyond side chains on the C(6)-position and reached to pyridine ring itself. It expedited us to synthesize diverse ring-modified analogues of a representative pyridine-3-ol, 6-acetamido-2,4,5-trimethylpyridin-3-ol (9). In the evaluation of compounds on their inhibitory actions against TNF-α-induced adhesion of monocytic cells to colonic epithelial cells, an in vitro model mimicking colon inflammation, the effects of compounds 9, 17, and 19 were greater than tofacitinib, an orally available anti-colitis drug, and compound 17 showed the greatest activity. In addition, TNF-α-induced angiogenesis, which permits more inflammatory cell migration into inflamed tissues, was significantly blocked by compounds 17 and 19 in a concentration-dependent manner. In the comparison of in vivo therapeutic effects of compounds 9, 17, and 19 on dextran sulfate sodium (DSS)-induced colitis in mice, compound 17 was the most potent and efficacious, and compound 19 was better than compound 9 which showed a similar degree of inhibitory effect to tofacitinib. Taken together, it seems that either the trimethyl system or the hydroxyl group on the pyridinol ring is essential to the activity. This finding might become a new milestone in the development of pyridinol-based anti-inflammatory bowel disease agents.

Potent Inhibitory Effect of BJ-3105, a 6-Alkoxypyridin-3-ol Derivative, on Murine Colitis Is Mediated by Activating AMPK and Inhibiting NOX.

Inflammatory bowel disease (IBD) is a chronic relapsing inflammation in the gastrointestinal tract. Biological therapeutics and orally available small molecules like tofacitinib (a JAK inhibitor) have been developed to treat IBD, but half of the patients treated with these drugs fail to achieve sustained remission. In the present study, we compared the therapeutic effects of BJ-3105 (a 6-alkoxypyridin-3-ol derivative) and tofacitinib in IBD. BJ-3105 induced activation of AMP-activated protein kinase (AMPK) in the kinase activity measurement and recovery from cytokine-induced AMPK deactivation in HT-29 human colonic epithelial cells. Similar to tofacitinib and D942 (an AMPK activator), BJ-3105 inhibited IL-6-induced JAK2/STAT3 phosphorylation and TNF-α-stimulated activation of IKK/NF-κB, and consequently, stimulus-induced upregulations of inflammatory cytokines and inflammasome components. In addition, unlike tofacitinib or D942, BJ-3105 inhibited NADPH oxidase (NOX) activation and consequent superoxide production induced by activators (mevalonate and geranylgeranyl pyrophosphate) of the NOX cytosolic component Rac. In mice, oral administration with BJ-3105 ameliorated dextran sulfate sodium (DSS)-induced colitis and azoxymethane/DSS-induced colitis-associated tumor formation (CAT) much more potently than that with tofacitinib. Moreover, BJ-3105 suppressed the more severe form of colitis and CAT formation in mice with AMPK knocked-out in macrophages (AMPKαfl/fl-Lyz2-Cre mice) with much greater efficacy than tofacitinib. Taken together, our findings suggest BJ-3105, which exerted a much better anti-colitis effect than tofacitinib through AMPK activation and NOX inhibition, is a promising candidate for the treatment of IBD.

AMPK is essential for IL-10 expression and for maintaining balance between inflammatory and cytoprotective signaling.

BACKGROUND: AMP-activated protein kinase (AMPK) exerts its anti-inflammatory effects by suppressing redox-sensitive nuclear factor kappa B (NF-κB) and pro-inflammatory cytokines including TNF-α. However, it is unclear whether AMPK regulates anti-inflammatory cytokine expressions in the presence of oxidative stress-induced inflammation. We sought to elucidate the mechanisms whereby AMPK regulates inflammatory cytokine expressions under NADPH oxidase (NOX)-induced oxidative stress. METHODS: HT-29 human colonic epithelial cells transfected with AMPKα shRNA and mouse models with AMPKα knocked out in epithelial cells (AMPKαfl/fl-Vil-Cre) or macrophages (AMPKαfl/fl-Lyz2-Cre) were used to examine the effects of AMPK and NOX on signaling pathways and cytokine expressions. RESULTS: In HT-29 cells, 5-hydroxytryptamine (5-HT)-induced NOX activity was enhanced by AMPKα silencing, and resulted in inflammatory cell death. AMPKα deletion specific for colon epithelial cells (AMPKαfl/fl-Vil-Cre) or macrophages (AMPKαfl/fl-Lyz2-Cre) intensified 5-HT- or dextran sulfate sodium (DSS)-induced upregulations of NOX2, TNF-α, and IL-6, but completely abolished basal and 5-HT- or DSS-induced upregulation of IL-10 in colon epithelium. Furthermore, 5-HT- and DSS-induced changes were accompanied by marked upregulations of increased inflammatory signaling pathways linked to NF-κB, AP-1, and STAT3 transcription factors, and to GATA, a cell fate-directing signaling. In addition, AMPKα deletion significantly fortified 5-HT- or DSS-induced downregulations of cytoprotective signaling pathways (Nrf2, HIF-1α, and KLF4). CONCLUSION: Basal AMPKα maintains an anti-inflammatory state by inhibiting NOX, balancing pro-/anti-inflammatory signaling pathways, and directing IL-10 production. When these regulatory roles of AMPK are diminished by oxidative stress, colon epithelium undergoes inflammation despite IL-10 production.

Synthesis, activity and mechanism of alkoxy-, carbamato-, sulfonamido-, thioureido-, and ureido-derivatives of 2,4,5-trimethylpyridin-3-ol against inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic immuno-inflammation in gastrointestinal tract. We have evaluated the activity of the compounds to inhibit the adhesion of monocytes to colon epithelial cells is triggered by a pro-inflammatory cytokine, tumour necrosis factor (TNF)-α. The in vitro activity of the compounds, 13b (an ureido-derivative), 14c, 14j, 14k, 14n (thioureido-), 18c and 18d (sulfonamido-), was in correlation with in vivo anti-colitis activity revealed as significant recovery in body- and colon-weights and colon myeloperoxidase level, a biochemical marker of inflammation reflecting neutrophil infiltration. In vivo, TNBS-induced changes in the expression of inflammatory cytokines (TNF-α, IL-6, IL-1ß, IL-10, and TGF-ß), NLRP3 inflammasome components (NLRP-3, Caspase-1, and IL-18), and epithelial junction molecules (E-cadherin, claudin2/3, and ZO-1) were blocked and recovered by oral administration of the compounds (1 mg/kg). Compound 14n which showed the best efficacy can be a promising lead for orally available therapeutics for pathology of IBD.

Participation of xCT in melanoma cell proliferation in vitro and tumorigenesis in vivo.

Our research group demonstrated that riluzole, an inhibitor of glutamatergic signaling reduced melanoma cell proliferation in vitro and tumor progression in vivo. The underlying mechanisms of riluzole are largely unknown. Microarray analyses on two human melanoma cell lines revealed that riluzole stimulates expression of the cystine-glutamate amino acid antiporter, xCT (SLC7A11). Western immunoblot analysis from cultured human melanoma or normal melanocytic cells showed that xCT was significantly overexpressed in most melanomas, but not normal cells. Studies using human tumor biopsy samples demonstrated that overexpression of xCT was correlated with cancer stage and progression. To further investigate if xCT is involved in melanoma cell growth, we derived several stable clones through transfection of exogenous xCT to melanoma cells that originally showed very low expression of xCT. The elevated xCT expression promoted cell proliferation in vitro and inversely, these melanoma clones showed a dose-dependent decrease in cell proliferation in response to riluzole treatment. Xenograft studies showed that these clones formed very aggressive tumors at a higher rate compared to vector controls. Conversely, treatment of xenograft-bearing animals with riluzole down-regulated xCT expression suggesting that xCT is a molecular target of riluzole. Furthermore, protein lysates from tumor biopsies of patients that participated in a riluzole monotherapy phase II clinical trial showed a reduction in xCT levels in post-treatment specimens from patients with stable disease. Taken together, our results show that xCT may be utilized as a marker to monitor patients undergoing riluzole-based chemotherapies.

Down-regulation of cathepsin S and matrix metalloproteinase-9 via Src, a non-receptor tyrosine kinase, suppresses triple-negative breast cancer growth and metastasis.

Triple-negative breast cancer (TNBC) is a highly metastatic breast cancer with poor prognosis. In the present study, we demonstrated that Src, a non-receptor tyrosine kinase, might provide an effective therapeutic strategy to overcome TNBC invasion and metastasis, which are mediated via the synergistic action of the lysosomal enzyme cathepsin S (CTSS) and gelatinase MMP-9. Knock-down of MMP-9 and CTSS using siRNAs resulted in a synergistic suppression of MDA-MB-231 cell invasion, which was similarly observed with pharmacological inhibitors. During the screening of new drug candidates that suppress both CTSS and MMP-9, BJ-2302, a novel 7-azaindolin-2-one derivative, was discovered. Src, an upstream activator of both pathways (PI3K/Akt and Ras/Raf/ERK) responsible for the expression of CTSS and MMP-9, was identified as a high-affinity target of BJ-2302 (IC90: 3.23 µM) through a Src kinase assay and a drug affinity responsive target stability (DARTS) assay. BJ-2302 effectively suppressed MDA-MB-231 cell invasion (Matrigel invasion assay) and metastasis (chorioallantoic membrane assay xenografted with MDA-MB-231-luc2-tdTomato cancer cells). Unlike Z-FL-COCHO (potent CTSS inhibitor), BJ-2302 did not induce any cytotoxicity in MCF-10A normal breast epithelial cells. Additionally, BJ-2302 (1 mg/kg) strongly suppressed TNBC cell proliferation in vitro and tumor growth in a xenograft mouse tumor model. The anti-metastatic and anti-tumor effects of BJ-2302 were superior to those of Z-FL-COCHO (1 mg/kg) or batimastat (30 mg/kg), a pan-MMP inhibitor. In summary, inhibition of Src kinase suppressed TNBC tumor growth and metastasis, and Src inhibitors such as BJ-2302 may constitute a novel therapeutic tool to treat breast cancer that expresses high levels of CTSS and MMP-9.

Antitumor activity of BJ-1207, a 6-amino-2,4,5-trimethylpyridin-3-ol derivative, in human lung cancer.

Enhanced expression of NADPH oxidase (NOX) and the subsequent production of reactive oxygen species (ROS) are associated with lung cancer. In the present study, fifty 6-amino-2,4,5-trimethylpyridin-3-ol derivatives were screened for anticancer activity by targeting NOX2-derived ROS. The compounds suppressed ROS production and decreased cancer cell viability (R2 = 0.79). Among the derivatives, the compound coded BJ-1207, which contained a 4-(hydroxydiphenylmethyl)piperidine moiety, exhibited the most effective anticancer activity against A549 lung cancer cell line and eight other cancer cell lines, including H1299, MCF-7, MDA-MB-231, HT-29, SW620, Mia PaCa-2, PANC-1, and U937. BJ-1207 also showed significantly lower inhibitory effects on kinase insert domain receptor (KDR) and c-KIT tyrosine kinase but higher inhibitory activity on NOX than those of sunitinib, a multi-receptor tyrosine kinase (RTK) inhibitor. In addition, BJ-1207-induced inhibition of RTK-downstream signaling pathways, such as ROS production, and expression of target genes, such as stem cell factor and transforming growth factor-α, were similar to those induced by sunitinib. In the xenograft chick tumor model, BJ-1207 inhibited lung tumor growth to a similar or much greater extent than that of sunitinib or cisplatin, respectively. Overall, the present study showed that BJ-1207, a vitamin B6-derived 2,4,5-trimethylpyridin-3-ol compound with azacyclonol moiety at C (6)-position of the pyridine ring, inhibited NOX activity and that it is a promising lead compound for developing anticancer drugs against lung cancer.

Synthesis and evaluation of 6-heteroarylamino-2,4,5-trimethylpyridin-3-ols as inhibitors of TNF-α-induced cell adhesion and inflammatory bowel disease.

Inflammatory bowel disease (IBD) is an inflammatory disease of the gastrointestinal tract with complex pathogenesis. Here, we synthesized 6-heteroarylamino analogues to inhibit TNF-α-induced adhesion of monocytes to colon epithelial cells which are implicated in the initial inflammation process of IBD. The best analogue, 16a, showed IC50 = 0.29 µM, which is about five orders of magnitude better than that of 5-aminosalicylic acid (5-ASA), a positive control. Oral administration of 6f and 16a dramatically ameliorated 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colon inflammation in rat. The ameliorating effects were accompanied by a high level of recovery in colon and body weights and in the myeloperoxidase (MPO) level. Consistently, the compounds suppressed the expression of intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein 1 (MCP-1). Moreover, they significantly suppressed the expression of pro-inflammatory cytokines such as TNF-α, IL-1ß, and IL-6 while increasing the level of IL-10, an anti-inflammatory cytokine.