Coumarin-chalcone hybrid LM-021 and indole derivative NC009-1 targeting inflammation and oxidative stress to protect BE(2)-M17 cells against α-synuclein toxicity.

Parkinson's disease (PD) is featured mainly by the loss of dopaminergic neurons and the presence of α-synuclein-containing aggregates in the substantia nigra of brain. The α-synuclein fibrils and aggregates lead to increased oxidative stress and neural toxicity in PD. Chronic inflammation mediated by microglia is one of the hallmarks of PD pathophysiology. In this report, we showed that coumarin-chalcone hybrid LM-021 and indole derivative NC009-1 reduced the expression of major histocompatibility complex-II, NLR family pyrin domain containing (NLRP) 3, caspase-1, inducible nitric oxide synthase, interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α in α-synuclein-activated mouse BV-2 microglia. Release of pro-inflammatory mediators including nitric oxide, IL-1ß, IL-6 and TNF-α was also mitigated. In BE(2)-M17 cells expressing A53T α-synuclein aggregates, LM-021 and NC009-1 reduced α-synuclein aggregation, neuroinflammation, oxidative stress and apoptosis, and promoted neurite outgrowth. These protective effects were mediated by downregulating NLRP1, IL-1ß and IL-6, and their downstream pathways including nuclear factor (NF)-κB inhibitor alpha (IκBα)/NF-κB P65 subunit (P65), c-Jun N-terminal kinase (JNK)/proto-oncogene c-Jun (JUN), mitogen-activated protein kinase 14 (P38)/signal transducer and activator of transcription (STAT) 1, and Janus kinase 2 (JAK2)/STAT3. The study results indicate LM-021 and NC009-1 as potential new drug candidates for PD.

Investigating Therapeutic Effects of Indole Derivatives Targeting Inflammation and Oxidative Stress in Neurotoxin-Induced Cell and Mouse Models of Parkinson's Disease.

Neuroinflammation and oxidative stress have been emerging as important pathways contributing to Parkinson's disease (PD) pathogenesis. In PD brains, the activated microglia release inflammatory factors such as interleukin (IL)-ß, IL-6, tumor necrosis factor (TNF)-α, and nitric oxide (NO), which increase oxidative stress and mediate neurodegeneration. Using 1-methyl-4-phenylpyridinium (MPP+)-activated human microglial HMC3 cells and the sub-chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD, we found the potential of indole derivative NC009-1 against neuroinflammation, oxidative stress, and neurodegeneration for PD. In vitro, NC009-1 alleviated MPP+-induced cytotoxicity, reduced NO, IL-1ß, IL-6, and TNF-α production, and suppressed NLR family pyrin domain containing 3 (NLRP3) inflammasome activation in MPP+-activated HMC3 cells. In vivo, NC009-1 ameliorated motor deficits and non-motor depression, increased dopamine and dopamine transporter levels in the striatum, and reduced oxidative stress as well as microglia and astrocyte reactivity in the ventral midbrain of MPTP-treated mice. These protective effects were achieved by down-regulating NLRP3, CASP1, iNOS, IL-1ß, IL-6, and TNF-α, and up-regulating SOD2, NRF2, and NQO1. These results strengthen the involvement of neuroinflammation and oxidative stress in PD pathogenic mechanism, and indicate NC009-1 as a potential drug candidate for PD treatment.

Pathomechanism characterization and potential therapeutics identification for SCA3 targeting neuroinflammation.

Polyglutamine (polyQ)-mediated spinocerebellar ataxias (SCA) are caused by mutant genes with expanded CAG repeats encoding polyQ tracts. The misfolding and aggregation of polyQ proteins result in increased reactive oxygen species (ROS) and cellular toxicity. Inflammation is a common manifestation of oxidative stress and inflammatory process further reduces cellular antioxidant capacity. Increase of activated microglia in the pons of SCA type 3 (SCA3) patients suggests the involvement of neuroinflammation in the disease pathogenesis. In this study, we evaluated the anti-inflammatory potentials of indole compound NC009-1, 4-aminophenol-arachidonic acid derivative AM404, quinoline compound VB-037 and chalcone-coumarin derivative LM-031 using human HMC3 microglia and SCA3 ATXN3/Q75-GFP SH-SY5Y cells. The four tested compounds displayed anti-inflammatory activity by suppressing NO, IL-1ß, TNF-α and IL-6 production and CD68 expression of IFN-γ-activated HMC3 microglia. In retinoic acid-differentiated ATXN3/Q75-GFP SH-SY5Y cells inflamed with IFN-γ-primed HMC3 conditioned medium, treatment with the tested compounds mitigated the increased caspase 1 activity and lactate dehydrogenase release, reduced polyQ aggregation and ROS and/or promoted neurite outgrowth. Examination of IL-1ß- and TNF-α-mediated signaling pathways revealed that the tested compounds decreased IκBα/P65, JNK/JUN and/or P38/STAT1 signaling. The study results suggest the potential of NC009-1, AM404, VB-037 and LM-031 in treating SCA3 and probable other polyQ diseases.

Neuroprotection of Indole-Derivative Compound NC001-8 by the Regulation of the NRF2 Pathway in Parkinson's Disease Cell Models.

Parkinson's disease (PD) is a common neurodegenerative disease accompanied by a loss of dopaminergic (DAergic) neurons. The development of therapies to prevent disease progression is the main goal of drug discovery. There is increasing evidence that oxidative stress and antioxidants may contribute to the pathogenesis and treatment of PD, respectively. In the present study, we investigated the antioxidative protective effects of the indole-derivative compound NC001-8 in DAergic neurons derived from SH-SY5Y cells and PD-specific induced pluripotent stem cells (PD-iPSCs) carrying a PARKIN ex5del mutation. In SH-SY5Y-differentiated DAergic neurons under 1-methyl-4-phenylpyridinium (MPP+) treatment, NC001-8 remarkably reduced the levels of reactive oxygen species (ROS) and cleaved caspase 3; upregulated nuclear factor erythroid 2-related factor 2 (NRF2) and NAD(P)H dehydrogenase, quinone 1 (NQO1); and promoted neuronal viability. In contrast, NRF2 knockdown abolished the effect of NC001-8 on the reduction of ROS and improvement of neuronal viability. In H2O2-treated DAergic neurons differentiated from PD-iPSCs, NC001-8 rescued the aberrant increase in ROS and cleaved caspase 3 by upregulating NRF2 and NQO1. Our results demonstrated the protective effect of NC001-8 in DAergic neurons via promoting the NRF2 antioxidative pathway and reducing ROS levels. We anticipate that our present in vitro assays may be a starting point for more sophisticated in vivo models or clinical trials that evaluate the potential of NC001-8 as a disease modifier for PD.

Indole Compound NC009-1 Augments APOE and TRKA in Alzheimer's Disease Cell and Mouse Models for Neuroprotection and Cognitive Improvement.

Alzheimer's disease (AD), associated with abnormal accumulation of amyloid-ß (Aß), is the most common cause of dementia among older people. A few studies have identified substantial AD biomarkers in blood but their results were inconsistent. Here we screened gene expression alterations on Aß-GFP SH-SY5Y neuronal model for AD, and evaluated the findings on peripheral leukocytes from 78 patients with AD and 56 healthy controls. The therapeutic responses of identified biomarker candidates were further examined in Aß-GFP SH-SY5Y neuronal and APP/PS1/Tau triple transgenic (3×Tg-AD) mouse models. Downregulation of apolipoprotein E (APOE) and tropomyosin receptor kinase A (TRKA) were detected in Aß-GFP SH-SY5Y cells and validated by peripheral leukocytes from AD patients. Treatment with an in-house indole compound NC009-1 upregulated the expression of APOE and TRKA accompanied with improvement of neurite outgrowth in Aß-GFP SH-SY5Y cells. NC009-1 further rescued the downregulated APOE and TRKA and reduced Aß and tau levels in hippocampus and cortex, and ameliorated cognitive deficits in streptozocin-induced hyperglycemic 3×Tg-AD mice. These results suggest the role of APOE and TRKA as potential peripheral biomarkers in AD, and offer a new drug development target of AD treatment. Further studies of a large series of AD patients will be warranted to verify the findings and confirm the correlation between these markers and therapeutic efficacy.

The indole compound NC009-1 inhibits aggregation and promotes neurite outgrowth through enhancement of HSPB1 in SCA17 cells and ameliorates the behavioral deficits in SCA17 mice.

Spinocerebellar ataxia type 17 (SCA17) is caused by the expansion of translated CAG repeat in the TATA box binding protein (TBP) gene encoding a long polyglutamine (polyQ) tract in the TBP protein, which leads to intracellular accumulation of aggregated TBP and cell death. The molecular chaperones act in preventing protein aggregation to ameliorate downstream harmful events. In this study, we used Tet-On cells with inducible SCA17 TBP/Q79-GFP expression to test five in-house NC009 indole compounds for neuroprotection. We found that both aggregation and polyQ-induced reactive oxygen species can be significantly prohibited by the tested NC009 compounds in Tet-On TBP/Q79 293 cells. Among the five indole compounds, NC009-1 up-regulated expression of heat shock protein family B (small) member 1 (HSPB1) chaperone to reduce polyQ aggregation and promote neurite outgrowth in neuronal differentiated TBP/Q79 SH-SY5Y cells. The increased HSPB1 thus ameliorated the increased BH3 interacting domain death agonist (BID), cytochrome c (CYCS) release, and caspase 3 (CASP3) activation which result in apoptosis. Knock down of HSPB1 attenuated the effects of NC009-1 on TBP/Q79 SH-SY5Y cells, suggesting that HSPB1 might be one of the major pathways involved for NC009-1 effects. NC009-1 further reduced polyQ aggregation in Purkinje cells and ameliorated behavioral deficits in SCA17 TBP/Q109 transgenic mice. Our results suggest that NC009-1 has a neuroprotective effect on SCA17 cell and mouse models to support its therapeutic potential in SCA17 treatment.

A triazole-conjugated benzoxazone induces reactive oxygen species and promotes autophagic apoptosis in human lung cancer cells.

Numerous approaches suggested that compounds with conjugated triazole moieties or benzoxazone pharmacores are effective to antagonize proliferation of human tumors. The current study reported that a synthetic triazole-conjugated benzoxazone, 4-((5-benzyl-1H-1,2,3-triazol-3-yl)-methyl)-7-methoxy-2H-benzo[b][1,4]-oxazin-3(4H)-one (BTO), inhibited growth rates of human non-small cell lung cancer cells. The cytotoxicity can be enhanced with increasing drug concentrations. More evidence supported that the induced reactive oxygen species lead to ultimate apoptotic cell death by recruiting autophagy. The mechanistic pathway as elucidated involved tumor suppressor p53 activation and LC3-1 conversion followed by PARP and procaspase-3 cleavage. Autophagy inhibition reverted apoptotic death and restored cell viabilities. BTO suppressed the development of A549 cell xenograft tumors by activating autophagy and apoptosis simultaneously. As an efficient tumor growth inhibitor with relatively small molecular weight, BTO is a viable addition to the existing list of lung cancer treatment.

A potent indolylquinoline alleviates growth of human lung cancer cell tumorspheres.

To fight cancer at its roots by targeting cancer stem cells is a promising approach for therapy. Previously, an indolylquinoline derivative, 3-((7-ethyl-1H-indol-3-yl)-methyl)-2-methylquinoline (EMMQ), was reported effectively inhibiting the growth of lung cancer cells through impairment of cellular mitochondria functions. To address more on drug efficiency, the study further exploited if EMMQ can impede the propagation of tumorspheres stemmed from non-small cell lung cancer cells. EMMQ inhibited proliferation of spheroids in culture. In animal models, administration of the drug attenuated the spheroid tumorigenicity. The activated apoptosis alleviated growth of xenograft tumors in immune-deficient mice as established by the enriched tumorspheres. More evidence suggested that the reduced stemness of the spheroid tumors is attributed to apoptotic death. The findings supported that EMMQ is an eligible approach to eradicate the minor but tumorigenic lung cancer tumorspheres.

Using gene expression database to uncover biology functions of 1,4-disubstituted 1,2,3-triazole analogues synthesized via a copper (I)-catalyzed reaction.

We have synthesized bioactive 1,4-disubstituted 1,2,3-triazole analogues containing 2H-1,4-benzoxazin-3-(4H)-one derivatives via 1,3-dipolar cycloaddition in the presence of CuI. All the reactions proceeded smoothly and afforded its desired products in excellent yields. Among these analogues, 3y exhibited a better cytotoxic effect on human hepatocellular carcinoma (HCC) Hep 3B cells and displayed less cytotoxicity on normal human umbilical vein endothelial cells, compared with Sorafenib, a targeted therapy for advanced HCC. 3y also induced stronger apoptosis and autophagy. Addition of curcumin enhanced 3y-induced cytotoxicity by further induction of autophagy. Using gene expression signatures of 3y to query Connectivity Map, a glycogen synthase kinase-3 inhibitor (AR-A014418) was predicted to display similar molecular action of 3y. Experiments further demonstrate that AR-A014418 acted like 3y, and vice versa. Overall, our data suggest the chemotherapeutic potential of 3y on HCC.

An indolylquinoline derivative activates DNA damage response and apoptosis in human hepatocellular carcinoma cells.

Human liver cancer is one of the most frequently diagnosed cancers worldwide. The development of resistance to therapy limits the application against the disease. To improve treatment, new effective anticancer agents are constantly pursued. Previously, we reported that an indolylquinoline, 3-((7-ethyl-1H-indol-3-yl)-methyl)-2-methylquinoline (EMMQ), is effective in suppressing the growth of human lung cancer by impairing mitochondria functions. The present study revealed that EMMQ inhibited cell growth and induced apoptosis in liver cancer cells, but not in normal cells. This study demonstrated that EMMQ induced DNA damage by activating p53 and γ-H2AX and cell arrest by suppressing cyclin D1 and CDK2. Damaged DNA injured mitochondrial functions by lowering the membrane potential and producing reactive oxygen species. The subsequent mitochondrial cytochrome c release attenuated pro-survival signals and increased apoptotic characteristics. Introduction of p53 shRNA abrogated drug effects by reducing DNA damage while maintaining mitochondria integrity. In brief, the study demonstrates that the effectiveness of EMMQ accentuated apoptosis of hepatocarcinoma cells by activating p53. Based on these collective findings, the study offered a new perspective of EMMQ that was shown to be a promising candidate to treat liver cancer.

A triazole derivative elicits autophagic clearance of polyglutamine aggregation in neuronal cells.

Trinucleotide CAG repeat expansion in the coding region of genes has a propensity to form polyglutamine (polyQ) aggregates that contribute to neuronal disorders. Strategies in elevating autophagy to disintegrate the insoluble aggregates without injuring cells have become a major goal for therapy. In this work, a triazole derivative, OC-13, was found accelerating autophagic clearance of polyQ aggregation in human neuroblastoma cells following induction of the enhanced green fluorescence-conjugated chimeric protein that enclosed 79 polyQ repeats (Q79-EGFP). OC-13 accelerated autophagy development and removed nuclear Q79-EGFP aggregates. The increase of Beclin-1, turnover of LC3-I to LC3-II and degradation of p62 supported autophagy activation. Pretreatment of autophagy inhibitor, bafilomycin A1, not only suppressed autophagolysome fusion, but also impeded aggregate eradication. The study also showed that c-Jun N-terminal kinase/Beclin-1 pathway was activated during OC-13 treatment and c-Jun N-terminal kinase inhibitor impaired autophagy and final breakdown. Autophagic clearance of the insoluble aggregates demonstrated the feasibility of OC-13 in alleviating neuronal disorders because of expanded glutamine stretches.

An indolylquinoline derivative promotes apoptosis in human lung cancer cells by impairing mitochondrial functions.

A number of effective anti-cancer drugs contain either indole or quinoline group. Compounds fused indole and quinoline moieties altogether as indolylquinoline were rarely reported as anti-cancer agents. We reported here that a synthetic indolylquinoline derivative, 3-((7-ethyl-1H-indol-3-yl)-methyl)-2-methylquinoline (EMMQ), inhibited the growth of human non-small cell lung cancer (NSCLC) cells in dose- and time-dependent manners. The cytotoxicity was mediated through apoptotic cell death that began with mitochondrial membrane potential interruption and DNA damage. EMMQ caused transient elevation of p53 that assists in cytochrome c release, cleavage of downstream PARP and procaspase-3 and mitochondria-related apoptosis. The degree of apoptotic cell death depends on the status of tumor suppressor p53 of the target cells. H1299 cells with stable ectopic expression of p53 induced cytotoxicity by disrupting mitochondria functions that differed with those transfected with mutant p53. Knocking-down of p53 attenuated drug effects. EMMQ suppressed the growth of A549 tumor cells in xenograft tumors by exhibiting apoptosis characteristics. Given its small molecular weight acting as an effective p53 regulator in NSCLC cells, EMMQ could be an addition to the current list of lung cancer treatment.

Indole and synthetic derivative activate chaperone expression to reduce polyQ aggregation in SCA17 neuronal cell and slice culture models.

In spinocerebellar ataxia type 17 (SCA17), the expansion of a translated CAG repeat in the TATA box binding protein (TBP) gene results in a long polyglutamine (polyQ) tract in the TBP protein, leading to intracellular accumulation of aggregated TBP and cell death. The molecular chaperones act in preventing protein aggregation to ameliorate downstream harmful events. In this study, we used Tet-On SH-SY5Y cells with inducible SCA17 TBP/Q79-green fluorescent protein (GFP) expression to test indole and synthetic derivative NC001-8 for neuroprotection. We found that indole and NC001-8 up-regulated chaperone expression to reduce polyQ aggregation in neuronal differentiated TBP/Q79 cells. The effects on promoting neurite outgrowth and on reduction of aggregation on Purkinje cells were also confirmed with cerebellar primary and slice cultures of SCA17 transgenic mice. Our results demonstrate how indole and derivative NC001-8 reduce polyQ aggregation to support their therapeutic potentials in SCA17 treatment.

Molecular iodine-mediated reaction of 2-(2-phenylethynyl)-Morita-Baylis-Hillman adducts: an easy route to naphthyl ketones and iodo-substituted isochromenes.

The molecular iodine-promoted reaction of 2-(2-phenylethynyl)-Morita-Baylis-Hillman adducts is reported. In the presence of I2, naphthyl ketone derivatives are produced, whereas in the presence of I2/K3PO4, iodo-substituted isochromene derivatives are produced.

The potential of indole and a synthetic derivative for polyQ aggregation reduction by enhancement of the chaperone and autophagy systems.

In polyglutamine (polyQ)-mediated disorders, the expansion of translated CAG repeats in the disease genes result in long polyQ tracts in their respective proteins, leading to intracellular accumulation of aggregated polyQ proteins, production of reactive oxygen species, and cell death. The molecular chaperones act in preventing protein misfolding and aggregation, thus inhibiting a wide range of harmful downstream events. In the circumstance of accumulation of aggregated polyQ proteins, the autophagic pathway is induced to degrade the misfolded or aggregated proteins. In this study, we used Flp-In 293/SH-SY5Y cells with inducible SCA3 ATXN3/Q75-GFP expression to test the effect of indole and synthetic derivatives for neuroprotection. We found that ATXN3/Q75 aggregation can be significantly prohibited in Flp-In 293 cells by indole and derivative NC001-8. Meanwhile, indole and NC001-8 up-regulated chaperones and autophagy in the same cell models. Both of them further promote neurite outgrowth in neuronal differentiated SH-SY5Y ATXN3/Q75-GFP cells. Our results demonstrate how indole and derivative NC001-8 are likely to work in reduction of polyQ-aggregation and provide insight into the possible effectual mechanism of indole compounds in polyQ spinocerebellar ataxia (SCA) patients. These findings may have therapeutic applications in a broad range of clinical situations.

Synthesis and evaluation of the cytotoxicities of tetraindoles: observation that the 5-hydroxy tetraindole (SK228) induces G2 arrest and apoptosis in human breast cancer cells.

Current chemical and biological interest in indole-3-carbinol (I3C) and its metabolites has resulted in the discovery of new biologically active indoles. As part of a program aimed at the development of indole analogues, tetraindoles 1-15 were prepared and their antiproliferative effects on human breast cancer cells were evaluated. The results show that the 5-hydroxy-tetraindole 8 (SK228) has optimum antiproliferative activity against breast adenocarcinoma (MCF 7 and MDA-MB-231) cells and that this activity involves G(2)-phase arrest of the cell cycle with a distinctive increase in the expression of cyclin B1 and phospho-cdc2. Further observations suggest that 5-hydroxy-tetraindole 8 induces apoptosis through externalization of membrane phosphatidylserine, DNA fragmentation, and activation of caspase-3. Given the fact that I3C and its metabolites have been shown to improve therapeutic efficacy and to have a broad range of antitumor activities in human cancer cells, the current findings have important pharmacological relevance as they open a promising route to the development of a potential chemotherapeutic application of tetraindoles as agents for the treatment of breast cancer.

Synthesis of isoxazoline N-oxides via [hydroxy(tosyloxy)iodo]benzene (HTIB)-mediated oxidative N-O coupling.

An HTIB mediated oxidative N-O coupling strategy for the synthesis of some isoxazoline N-oxide derivatives from ß-hydroxyketoximes is described, along with a comparative study of the efficiency of N-O coupling in two different solvents. A plausible mechanism for the conversion is proposed.

Synthesis and structure-activity relationships of novel furazan-3,4-diamide analogs as potent anti-cancer agents.

This study describes the synthesis and structure-activity relationships of a series of furazan-3,4-diamide analogs. 1,2,5-Oxadiazole ring and electron-withdrawing substituent on the phenyl ring are proposed to be the important elements which contribute to a significant extent maximal potency of anti-proliferation effect.

Novel 2-step synthetic indole compound 1,1,3-tri(3-indolyl)cyclohexane inhibits cancer cell growth in lung cancer cells and xenograft models.

BACKGROUND: The clinical responses to chemotherapy in lung cancer patients are unsatisfactory. Thus, the development of more effective anticancer drugs for lung cancer is urgently needed. METHODS: A 2-step novel synthetic compound, referred to as 1,1,3-tri(3-indolyl)cyclohexane (3-indole), was generated in high purity and yield. 3-Indole was tested for its biologic activity in A549, H1299, H1435, CL1-1, and H1437 lung cancer cells. Animal studies were also performed. RESULTS: The data indicate that 3-indole induced apoptosis in various lung cancer cells. Increased cytochrome-c release from mitochondria to cytosol, decreased expression of antiapoptotic Bcl-2, and increased expression of proapoptotic Bax were observed. In addition, 3-indole stimulated caspases-3, -9, and to a lesser extent caspase-8 activities in cancer cells, suggesting that the intrinsic mitochondria pathway was the potential mechanism involved in 3-indole-induced apoptosis. 3-Indole-induced a concentration-dependent mitochondrial membrane potential dissipation and an increase in reactive oxygen species (ROS) production. Activation of c-Jun N-terminal kinase (JNK) and triggering of DNA damage were also apparent. Note that 3-indole-induced JNK activation and DNA damage can be partially suppressed by an ROS inhibitor. Apoptosis induced by 3-indole could be abrogated by ROS or JNK inhibitors, suggesting the importance of ROS and JNK stress-related pathways in 3-indole-induced apoptosis. Moreover, 3-indole showed in vivo antitumor activities against human xenografts in murine models. CONCLUSIONS: On the basis of its potent anticancer activity in cell and animal models, the data suggest that this 2-step synthetic 3-indole compound of high purity and yield is a potential candidate to be tested as a lead pharmaceutical compound for cancer treatment.