Design and synthesis of a monocyclic derivative as a selective ACC1 inhibitor by chemical modification of biphenyl ACC1/2 dual inhibitors.

A structure-activity relationship (SAR) study towards novel ACC1-selective inhibitors was carried out by modifying the molecular length of the linker in biaryl derivative 1 g, an ACC1/2 dual inhibitor. Ultimately, this leads us to discover novel phenoxybenzyloxy derivative 1i as a potent ACC1-selective inhibitor. Further chemical modification of this scaffold to improve cellular potency as well as physicochemical and pharmacokinetic (PK) properties produced N-2-(pyridin-2-ylethyl)acetamide derivative 1n, which showed highly potent ACC1-selective inhibition as well as sufficient PK profile for further in vivo evaluations. Oral administration of 1n significantly reduced the concentration of malonyl-CoA in HCT-116 xenograft tumors at doses of 100 mg/kg. Accordingly, our novel series of potent ACC1-selective inhibitors represents a set of useful orally-available research tools, as well as potential therapeutic agents for cancer and fatty acid-related diseases.

The identification and pharmacological evaluation of potent, selective and orally available ACC1 inhibitor.

In our effort to explore the potential of ACC1-selective inhibitor as in vivo probe molecule, a series of 1,3-benzoxazole derivatives was synthesized. Previously, we reported a series of novel bicyclic and monocyclic ACC1-selective inhibitors. Among them, compound 1a exhibited highly potent cellular activity (acetate uptake IC50 = 0.76 nM) as well as promising in vivo PD efficacy. However, compound 1a caused severe body weight reduction in repeated dose administration in the mouse model. Since 1a showed potent inhibitory activity against mouse ACC1 as well as strong inhibition of mouse ACC2, we further examined a series of 1a analogues in order to reduce undesirable body weight change. The replacement of acetamide moiety with ureido moiety dramatically improved selectivity of mouse ACC1 against ACC2. In addition, analogue 1b displayed favorable bioavailability in mouse cassette dosing PK study, hence in vivo PD studies were also carried out. Oral administration of 1b significantly reduced the concentration of malonyl-CoA in HCT-116 xenograft tumors at doses of more than 30 mg/kg. Furthermore, compound 1b showed significant antitumor efficacy in 786-O xenograft mice at an oral dose of 30 mg/kg (T/C = 0.5%). Accordingly, our novel potent ACC1-selective inhibitor represents a set of useful orally-available research tools, as well as potential therapeutic agents particularly in terms of new cancer therapies.

Design and synthesis of a novel 1H-pyrrolo[3,2-b]pyridine-3-carboxamide derivative as an orally available ACC1 inhibitor.

We initiated our structure-activity relationship (SAR) studies for novel ACC1 inhibitors from 1a as a lead compound. Our initial SAR studies of 1H-Pyrrolo[3,2-b]pyridine-3-carboxamide scaffold revealed the participation of HBD and HBA for ACC1 inhibitory potency and identified 1-methyl-1H-pyrrolo[3,2-b]pyridine-3-carboxamide derivative 1c as a potent ACC1 inhibitor. Although compound 1c had physicochemical and pharmacokinetic (PK) issues, we investigated the 1H-pyrrolo[3,2-b]pyridine core scaffold to address these issues. Accordingly, this led us to discover a novel 1-isopropyl-1H-pyrrolo[3,2-b]pyridine-3-carboxamide derivative 1k as a promising ACC1 inhibitor, which showed potent ACC1 inhibition as well as sufficient cellular potency. Since compound 1k displayed favorable bioavailability in mouse cassette dosing PK study, we conducted in vivo Pharmacodynamics (PD) studies of this compound. Oral administration of 1k significantly reduced the concentration of malonyl-CoA in HCT-116 xenograft tumors at a dose of 100 mg/kg. Accordingly, our novel series of potent ACC1 inhibitors represent useful orally-available research tools, as well as potential therapeutic agents for cancer and fatty acid related diseases.

Prolyl-tRNA synthetase inhibition promotes cell death in SK-MEL-2 cells through GCN2-ATF4 pathway activation.

Protein translation is highly activated in cancer tissues through oncogenic mutations and amplifications, and this can support survival and aberrant proliferation. Therefore, blocking translation could be a promising way to block cancer progression. The process of charging a cognate amino acid to tRNA, a crucial step in protein synthesis, is mediated by tRNA synthetases such as prolyl tRNA synthetase (PRS). Interestingly, unlike pan-translation inhibitors, we demonstrated that a novel small molecule PRS inhibitor (T-3861174) induced cell death in several tumor cell lines including SK-MEL-2 without complete suppression of translation. Additionally, our findings indicated that T-3861174-induced cell death was caused by activation of the GCN2-ATF4 pathway. Furthermore, the PRS inhibitor exhibited significant anti-tumor activity in several xenograft models without severe body weight losses. These results indicate that PRS is a druggable target, and suggest that T-3861174 is a potential therapeutic agent for cancer therapy.

Discovery of Novel and Potent Stearoyl Coenzyme A Desaturase 1 (SCD1) Inhibitors as Anticancer Agents.

A lead compound A was identified previously as an stearoyl coenzyme A desaturase (SCD) inhibitor during research on potential treatments for obesity. This compound showed high SCD1 binding affinity, but a poor pharmacokinetic (PK) profile and limited chemical accessibility, making it suboptimal for use in anticancer research. To identify potent SCD1 inhibitors with more promising PK profiles, we newly designed a series of 'non-spiro' 4, 4-disubstituted piperidine derivatives based on molecular modeling studies. As a result, we discovered compound 1a, which retained moderate SCD1 binding affinity. Optimization around 1a was accelerated by analyzing Hansch-Fujita and Hammett constants to obtain 4-phenyl-4-(trifluoromethyl)piperidine derivative 1n. Fine-tuning of the azole moiety of 1n led to compound 1o (T-3764518), which retained nanomolar affinity and exhibited an excellent PK profile. Reflecting the good potency and PK profile, orally administrated compound 1o showed significant pharmacodynamic (PD) marker reduction (at 0.3mg/kg, bid) in HCT116 mouse xenograft model and tumor growth suppression (at 1mg/kg, bid) in 786-O mouse xenograft model. In conclusion, we identified a new series of SCD1 inhibitors, represented by compound 1o, which represents a promising new chemical tool suitable for the study of SCD1 biology as well as the potential development of novel anticancer therapies.

Acute cardiac support with intravenous milrinone promotes recovery from early brain injury in a murine model of severe subarachnoid haemorrhage.

Early brain injury/ischaemia (EBI) is a serious complication early after subarachnoid haemorrhage (SAH) that contributes to development of delayed cerebral ischaemia (DCI). This study aimed to determine the role of inotropic cardiac support using milrinone (MIL) on restoring acute cerebral hypoperfusion attributable to EBI and improving outcomes after experimental SAH. Forty-three male C57BL/6 mice were assigned to either sham surgery (SAH-sham), SAH induced by endovascular perforation plus postconditioning with 2% isoflurane (Control), or SAH plus isoflurane combined with MIL with and without hypoxia-inducible factor inhibitor (HIF-I) pretreatment. Cardiac output (CO) during intravenous MIL infusion (0.25-0.75 µg/kg/min) between 1.5 and 2.5 hours after SAH induction was monitored with Doppler echocardiography. Magnetic resonance imaging (MRI)-continuous arterial spin labelling was used for quantitative cerebral blood flow (CBF) measurements. Neurobehavioral function was assessed daily by neurological score and open field test. DCI was analyzed 3 days later by determining infarction on MRI. Mild reduction of cardiac output (CO) and global cerebral blood flow (CBF) depression were notable early after SAH. MIL increased CO in a dose-dependent manner (P<.001), which was accompanied by improved hypoperfusion, incidence of DCI and functional recovery than Control (P<.05). The neuroprotective effects afforded by MIL or Control were attenuated by hypoxia-inducible factor (HIF) inhibition (P<.05). These results suggest that MIL improves acute hypoperfusion by its inotropic effect, leading to neurobehavioral improvement in mice after severe SAH, in which HIF may be acting as a critical mediator.

Synthesis and evaluation of hedgehog signaling inhibitor with novel core system.

As we previously reported, N-methylpyrrolo[3,2-c]pyridine derivatives 1 (TAK-441) was discovered as a clinical candidate of hedgehog (Hh) signaling inhibitor by modification of the upper part. We next focused on modification of the lower part including core skeletons to discover new Hh signaling inhibitors with novel core rings. Efforts to find novel chemotypes by using X-ray single crystal structure analysis led to some potent Hh signaling inhibitors (2c, 2d, 2e, 2f) with novel core ring systems, which had benzamide moiety at the 5-position as a key component for potent activity. The suppression of Gli1 expression with these new Hh signaling inhibitors were weaker than that of compound 1 (TAK-441) because of low pharmacokinetic property. We recognized again TAK-441 is a good compound as clinical candidate with good structural and pharmacokinetic advantages.

Acoustic characteristics of biosonar sounds of free-ranging botos (Inia geoffrensis) and tucuxis (Sotalia fluviatilis) in the Negro River, Amazon, Brazil.

Odontoceti emit broadband high-frequency clicks on echolocation for orientation or prey detection. In the Amazon Basin, two odontoceti species, boto (Amazon River dolphin, Inia geoffrensis) and tucuxi (Sotalia fluviatilis), live sympatrically. The acoustic characteristics of the echolocation clicks of free-ranging botos and tucuxis were measured with a hydrophone array consisting of a full-band and an acoustic event recorder (A-tag). The clicks of the two species were short-duration broadband signals. The apparent source level was 201 dB 1 µPa peak-to-peak at 1 m in the botos and 181 dB 1 µPa peak-to-peak at 1 m in the tucuxis, and the centroid frequency was 82.3 kHz in the botos and 93.1 kHz in the tucuxis. The high apparent source level and low centroid frequency are possibly due to the difference in body size or sound production organs, especially the nasal structure, the sound source of clicks in odontoceti.

First atroposelective Chan-Lam coupling for the synthesis of C-N linked biaryls.

The first atroposelective Chan-Lam coupling for the synthesis of C-N axial enantiomers is reported with good yields and ee. MnO2 additive is crucial for the success of the coupling. The longstanding problem of the lack of enantioselective synthesis to make chiral C-N linked atropisomers is solved.

A multimodal detection model of dolphins to estimate abundance validated by field experiments.

Abundance estimation of marine mammals requires matching of detection of an animal or a group of animal by two independent means. A multimodal detection model using visual and acoustic cues (surfacing and phonation) that enables abundance estimation of dolphins is proposed. The method does not require a specific time window to match the cues of both means for applying mark-recapture method. The proposed model was evaluated using data obtained in field observations of Ganges River dolphins and Irrawaddy dolphins, as examples of dispersed and condensed distributions of animals, respectively. The acoustic detection probability was approximately 80%, 20% higher than that of visual detection for both species, regardless of the distribution of the animals in present study sites. The abundance estimates of Ganges River dolphins and Irrawaddy dolphins fairly agreed with the numbers reported in previous monitoring studies. The single animal detection probability was smaller than that of larger cluster size, as predicted by the model and confirmed by field data. However, dense groups of Irrawaddy dolphins showed difference in cluster sizes observed by visual and acoustic methods. Lower detection probability of single clusters of this species seemed to be caused by the clumped distribution of this species.

Discovery of the investigational drug TAK-441, a pyrrolo[3,2-c]pyridine derivative, as a highly potent and orally active hedgehog signaling inhibitor: modification of the core skeleton for improved solubility.

We recently reported the discovery of the novel pyrrolo[3,2-c]quinoline-4-one derivative 1 as a potent inhibitor of Hedgehog (Hh) pathway signaling. However, the PK evaluation of 1 at high dosage (100 mg/kg) revealed the C(max) value 3.63 µg/mL, likely due to poor solubility of this compound. Efforts to improve solubility by reducing the aromatic ring count of the core system led to N-methylpyrrolo[3,2-c]pyridine derivative 11. Further optimization of the 3-alkoxy group led to compound 11d with acceptable solubility and potent Hh inhibitory activity. Compound 11d suppressed transcription factor Gli1 mRNA expression in tumor-associated stromal tissue and inhibited tumor growth (treatment/control ratio, 3%) in a mouse medulloblastoma allograft model owing to the improved PK profile based on increased solubility. Compound 11d (TAK-441) is currently in clinical trials for the treatment of advanced solid tumors.

Discovery of pyrrolo[3,2-c]quinoline-4-one derivatives as novel hedgehog signaling inhibitors.

The Hedgehog (Hh) signaling pathway plays a significant role in the regulation of cell growth and differentiation during embryonic development. Since activation of the Hh signaling pathway is implicated in several types of human cancers, inhibitors of this pathway could be promising anticancer agents. Using high throughput screening, thieno[3,2-c]quinoline-4-one derivative 9a was identified as a compound of interest with potent in vitro activity but poor metabolic stability. Our efforts focused on enhancement of in vitro inhibitory activity and metabolic stability, including core ring conversion and side chain optimization. This led to the discovery of pyrrolo[3,2-c]quinoline-4-one derivative 12b, which has a structure distinct from previously reported Hh signaling inhibitors. Compound 12b suppressed stromal Gli1 mRNA expression in a murine model and demonstrated antitumor activity in a murine medulloblastoma allograft model.

Investigating the Therapeutic Potential of LSD1 Enzyme Activity-Specific Inhibition by TAK-418 for Social and Memory Deficits in Rodent Disease Models.

Inhibition of lysine-specific demethylase 1 (LSD1) enzyme activity is a promising approach to treat diseases associated with epigenetic dysregulation, such as neurodevelopmental disorders. However, this concept has not been fully validated because genetic LSD1 deletion causes embryonic lethality and conventional LSD1 inhibitors cause thrombocytopenia via the dissociation of LSD1-cofactor complex. To characterize the therapeutic potential of LSD1 enzyme inhibition, we used TAK-418 and T-448, the LSD1 enzyme activity-specific inhibitors with minimal impact on the LSD1-cofactor complex. TAK-418 and T-448, by inhibiting brain LSD1 enzyme activity, consistently improved social deficits in animal models of neurodevelopmental disorders without causing thrombocytopenia. Moreover, TAK-418 improved memory deficits caused by aging or amyloid precursor protein overexpression. In contrast, TAK-418 did not improve memory deficits caused by miR-137 overexpression. Thus, miR-137 modulation may be involved in memory improvement by LSD1 inhibition. TAK-418 warrants further investigation as a novel therapeutic agent for diseases with epigenetic dysregulation.

Adiponectin regulates the circadian rhythm of glucose and lipid metabolism.

Adiponectin is a cytokine secreted from adipocytes and regulates metabolism. Although serum adiponectin levels show diurnal variations, it is not clear if the effects of adiponectin are time-dependent. Therefore, this study conducted locomotor activity analyses and various metabolic studies using the adiponectin knockout (APN (-/-)) and the APN (+/+) mice to understand whether adiponectin regulates the circadian rhythm of glucose and lipid metabolism. We observed that the adiponectin gene deficiency does not affect the rhythmicity of core circadian clock genes expression in several peripheral tissues. In contrast, the adiponectin gene deficiency alters the circadian rhythms of liver and serum lipid levels and results in the loss of the time dependency of very-low-density lipoprotein-triglyceride secretion from the liver. In addition, the whole-body glucose tolerance of the APN (-/-) mice was normal at CT10 but reduced at CT22, compared to the APN (+/+) mice. The decreased glucose tolerance at CT22 was associated with insulin hyposecretion in vivo. In contrast, the gluconeogenesis activity was higher in the APN (-/-) mice than in the APN (+/+) mice throughout the day. These results indicate that adiponectin regulates part of the circadian rhythm of metabolism in the liver.

Genetic background affects properties of satellite cells and mdx phenotypes.

Duchenne muscular dystrophy (DMD) is the most common lethal genetic disorder of children. The mdx (C57BL/10 background, C57BL/10-mdx) mouse is a widely used model of DMD, but the histopathological hallmarks of DMD, such as the smaller number of myofibers, accumulation of fat and fibrosis, and insufficient regeneration of myofibers, are not observed in adult C57BL/10-mdx except for in the diaphragm. In this study, we showed that DBA/2 mice exhibited decreased muscle weight, as well as lower myofiber numbers after repeated degeneration-regeneration cycles. Furthermore, the self-renewal efficiency of satellite cells of DBA/2 is lower than that of C57BL/6. Therefore, we produced a DBA/2-mdx strain by crossing DBA/2 and C57BL/10-mdx. The hind limb muscles of DBA/2-mdx mice exhibited lower muscle weight, fewer myofibers, and increased fat and fibrosis, in comparison with C57BL/10-mdx. Moreover, remarkable muscle weakness was observed in DBA/2-mdx. These results indicate that the DBA/2-mdx mouse is a more suitable model for DMD studies, and the efficient satellite cell self-renewal ability of C57BL/10-mdx might explain the difference in pathologies between humans and mice.

Welsh onion attenuates hyperlipidemia in rats fed on high-fat high-sucrose diet.

The effects of two types of Welsh onion, green-leafy and white-sheath types, on hyperlipidemia in rats fed on diets high in fat and sucrose were studied. A significant lowering effect on cholesterol in the plasma and on total lipids, triacylglycerol, and cholesterol in the liver was observed in rats fed on the green, but not white, Welsh onion. These Welsh onions had no significant effect on the hepatic enzyme activities responsible for fatty acid synthesis and degradation. The results suggest that the green Welsh onion might be effective in attenuating hyperlipidemia in a manner other than affecting fatty acid metabolism in the liver. Kaempferol seemed to be one of the components in green Welsh onion acting to lower lipid deposition.

Discovery of a Novel, Highly Potent, and Selective Thieno[3,2-d]pyrimidinone-Based Cdc7 Inhibitor with a Quinuclidine Moiety (TAK-931) as an Orally Active Investigational Antitumor Agent.

In our pursuit of developing a novel, potent, and selective cell division cycle 7 (Cdc7) inhibitor, we optimized the previously reported thieno[3,2-d]pyrimidinone analogue I showing time-dependent Cdc7 kinase inhibition and slow dissociation kinetics. These medicinal chemistry efforts led to the identification of compound 3d, which exhibited potent cellular activity, excellent kinase selectivity, and antitumor efficacy in a COLO205 xenograft mouse model. However, the issue of formaldehyde adduct formation emerged during a detailed study of 3d, which was deemed an obstacle to further development. A structure-based approach to circumvent the adduct formation culminated in the discovery of compound 11b (TAK-931) possessing a quinuclidine moiety as a preclinical candidate. In this paper, the design, synthesis, and biological evaluation of this series of compounds will be presented.

Suppression of macrophage functions impairs skeletal muscle regeneration with severe fibrosis.

When damaged, skeletal muscle regenerates. In the early phases of regeneration, inflammatory cells such as neutrophils/granulocytes and macrophages infiltrate damaged muscle tissue. To reveal the roles of macrophages during skeletal muscle regeneration, we injected an antibody, AFS98 that blocks the binding of M-CSF to its receptor into normal mice that received muscle damages. Anti-M-CSF receptor administration suppressed macrophage but not neutrophil infiltration. Histological study indicated that suppression of macrophages function leads to the incomplete muscle regeneration. In addition FACS and immunohistochemical study showed that the acute lack of macrophages delayed proliferation and differentiation of muscle satellite cells in vivo. Furthermore, mice injected with the anti-M-CSF receptor antibody exhibited not only adipogenesis, but also significant collagen deposition, i.e., fibrosis and continuous high expression of connective tissue growth factor. Finally we indicate that these fibrosis markers were strongly enriched in CD90(+) cells that do not include myogenic cells. These results indicate that macrophages directly affect satellite cell proliferation and that a macrophage deficiency severely impairs skeletal muscle regeneration and causes fibrosis.

Molecular mechanism and potential target indication of TAK-931, a novel CDC7-selective inhibitor.

Replication stress (RS) is a cancer hallmark; chemotherapeutic drugs targeting RS are widely used as treatments for various cancers. To develop next-generation RS-inducing anticancer drugs, cell division cycle 7 (CDC7) has recently attracted attention as a target. We have developed an oral CDC7-selective inhibitor, TAK-931, as a candidate clinical anticancer drug. TAK-931 induced S phase delay and RS. TAK-931-induced RS caused mitotic aberrations through centrosome dysregulation and chromosome missegregation, resulting in irreversible antiproliferative effects in cancer cells. TAK-931 exhibited significant antiproliferative activity in preclinical animal models. Furthermore, in indication-seeking studies using large-scale cell panel data, TAK-931 exhibited higher antiproliferative activities in RAS-mutant versus RAS-wild-type cells; this finding was confirmed in pancreatic patient-derived xenografts. Comparison analysis of cell panel data also demonstrated a unique efficacy spectrum for TAK-931 compared with currently used chemotherapeutic drugs. Our findings help to elucidate the molecular mechanisms for TAK-931 and identify potential target indications.

Discovery of Novel Selective Acetyl-CoA Carboxylase (ACC) 1 Inhibitors.

We initiated our structure-activity relationship (SAR) studies for selective ACC1 inhibitors from 1a as a lead compound. SAR studies of bicyclic scaffolds revealed many potent and selective ACC1 inhibitors represented by 1f; however most of them had physicochemical issues, particularly low aqueous solubility and potent CYP inhibition. To address these two issues and improve the druglikeness of this chemical series, we converted the bicyclic scaffold into a monocyclic framework. Ultimately, this lead us to discover a novel monocyclic derivative 1q as a selective ACC1 inhibitor, which showed highly potent and selective ACC1 inhibition as well as acceptable solubility and CYP inhibition profiles. Since compound 1q displayed favorable bioavailability in mouse cassette dosing testing, we conducted in vivo PD studies of this compound. Oral administration of 1q significantly reduced the concentration of malonyl-CoA in HCT-116 xenograft tumors at doses of more than 30 mg/kg. Accordingly, our novel series of selective ACC1 inhibitors represents a set of useful orally available research tools, as well as potential therapeutic agents for cancer and fatty acid related diseases.