Discovery and structure-based design of a new series of potent and selective PPARδ agonists utilizing a virtual screening method.

Novel PPARδ agonists, 2-(1-piperidinyl)-1,3-benzothiazole derivatives were discovered by our proprietary docking-based virtual screening technique. Compound 1 as the initial hit was effectively modified to acquire PPARδ agonist activity, resulting in the discovery of compound 12 with high agonistic potency for PPARδ and selectivity over PPARα and PPARγ. Compound 12 also had good ADME profiles and showed in vivo efficacy as a lead.

Determination of Significant Prognostic Factors for Maxillary Gingival Squamous Cell Carcinoma in 90 Cases.

Maxillary gingival squamous cell carcinoma (MGSCC) occurs rather infrequently, compared to tongue and mandibular gingival carcinomas, among the cancers of the oral cavity. Therefore, significant numbers of MGSCC cases have not been statistically analysed. The aim of this study is to clarify the prognostic factors for MGSCC. We performed the statistical analysis of 90 MGSCC cases primarily treated in our department from 1999 to 2014. The patients (male: 36, female: 54) were aged between 38 and 93 years, and the mean age was 68.7 years. The number of patients in each tumour stage according to the TNM classification was as follows: T1: 15 cases, T2: 32 cases, T3: 13 cases, and T4: 30 cases. Forty-two patients were treated only by surgery, 5 only by radiotherapy, 3 by preoperative radiotherapy and surgery, and 40 patients were treated by combination therapy with preoperative chemoradiotherapy and surgery. Neck dissections were performed in 40 cases including 29 cases (11 primary and 18 secondary cases) of histopathologically diagnosed lymph node metastases. Extranodal extension was found in 74.3% cases with metastatic lymph nodes. The 5-year overall survival rate was 81.9%. In univariate analysis, the site of occurrence, stage of tumour, lymph node metastasis, and treatment contributed to the 5-year survival rate. Multivariate analysis demonstrated that the site of occurrence (posterior region) was an independent prognostic factor. Seventeen deaths occurred due to the primary disease, while three deaths were caused by other diseases. The posterior region cancers, according to the classification based on site of occurrence, were independent predictors of poor 5-year overall survival rate.

Identification of Novel Carbocyclic Pyrimidine Cyclic Dinucleotide STING Agonists for Antitumor Immunotherapy Using Systemic Intravenous Route.

Stimulator of Interferon Genes (STING) plays an important role in innate immunity by inducing type I interferon production upon infection with intracellular pathogens. STING activation can promote increased T-cell activation and inflammation in the tumor microenvironment, resulting in antitumor immunity. Natural and synthetic cyclic dinucleotides (CDNs) are known to activate STING, and several synthetic CDN molecules are being investigated in the clinic using an intratumoral administration route. Here, we describe the identification of STING agonist 15a, a cyclic dinucleotide structurally diversified from natural ligands with optimized properties for systemic intravenous (iv) administration. Our studies have shown that STING activation by 15a leads to an acute innate immune response as measured by cytokine secretion and adaptive immune response via activation of CD8+ cytotoxic T-cells, which ultimately provides robust antitumor efficacy.

Discovery of TAK-981, a First-in-Class Inhibitor of SUMO-Activating Enzyme for the Treatment of Cancer.

SUMOylation is a reversible post-translational modification that regulates protein function through covalent attachment of small ubiquitin-like modifier (SUMO) proteins. The process of SUMOylating proteins involves an enzymatic cascade, the first step of which entails the activation of a SUMO protein through an ATP-dependent process catalyzed by SUMO-activating enzyme (SAE). Here, we describe the identification of TAK-981, a mechanism-based inhibitor of SAE which forms a SUMO-TAK-981 adduct as the inhibitory species within the enzyme catalytic site. Optimization of selectivity against related enzymes as well as enhancement of mean residence time of the adduct were critical to the identification of compounds with potent cellular pathway inhibition and ultimately a prolonged pharmacodynamic effect and efficacy in preclinical tumor models, culminating in the identification of the clinical molecule TAK-981.

Does a Vascularized Fibula Free Bone Grafted Immediately After Hemimandibulectomy in a Child Grow or Relapse During Adolescence?

For young growing children before the end of skeletal maturity, the growth activity of the grafted bone after hemimandibulectomy is not well-known. After an adolescence, such a patient may have facial deformity because the anterior growth point of the mandible is in the condylar neck. A 13-year-old boy was performed hemimandibulectomy with immediate mandibular reconstruction by fibula free flap (FFF) because of a huge ameloblastic fibroma. The authors evaluated the length of FFF on the images of computed tomography (CT) at 5 and 60 months after the operation and compared them by calculating growth rates. Five years after surgery, his facial appearance was symmetry and mandibular function was satisfaction. Although the mandibular bone in the contralateral side grew during 5-year follow-up, the vascularized FFF grafted in the child patient did not significantly grow. Moreover, spontaneous regeneration (SR) and the gradual osteosclerosis were confirmed on the left distal edge of the FFF on the CT imaging. The arrival of SR at the left distal edge of the FFF was considered a part of the reason to compensate the unchanging growth rate of the grafted FFF and contribute for the postoperative good functional and esthetic results.

Primary intraosseous squamous cell carcinoma derived from a maxillary cyst: A case report and literature review.

Primary intraosseous squamous cell carcinoma (PIOSCC) is a rare malignant central jaw tumor derived from odontogenic epithelial remnants. PIOSCC predominantly affects the mandible, although both jawbones may be involved. This case report describes a PIOSCC type 2 of the maxilla in a 37-year-old man, treated by partial maxillectomy. Histopathologically, the tumor was diagnosed as PIOSCC derived from an odontogenic cyst. Postoperatively, the patient has been followed up for 53 months, with no recurrence of the disease. We herein describe the clinical details, treatment results and histopathological characteristics of a rare case of PIOSCC derived from a maxillary odontogenic cyst with reference to the relevant literature.

Clinical study on mandibular fracture after marginal resection of the mandible.

OBJECTIVES: Postoperative mandibular fracture (PMF) after marginal resection (MR) of the mandible remains an unresolved issue, and it has been reported that at least 10 mm of postoperative mandibular body height (PMBH) is required to prevent PMF. This study evaluated the clinical, physical, and structural risk factors for PMF in MR patients and determined appropriate preventive measures for PMF. STUDY DESIGN: This retrospective study included 44 patients with lower gingival carcinoma who underwent MR. PMF occurred in four of these patients. Thirteen associated factors identified from medical records and radiographs were statistically analyzed. RESULTS: Mandibular body height (MBH) preservation ratio originally evaluated as less than 0.3, more than 20 remaining teeth after surgery, and inferior alveolar canal (IAC) exposure were significant risk factors for PMF. Prostheses and number of remaining teeth were also correlated with PMF. CONCLUSIONS: The preserved mandibular bone should be reinforced in patients with an MBH preservation ratio of less than 0.3, more than 20 remaining teeth after surgery, and intraoperative IAC exposure. Patients with prostheses are at an increased risk of PMF compared with those without because of stable occlusion and a strong occlusal force. Our novel findings provide useful reference standards for PMF prevention in MR patients.

Clinical Study of 597 Oral Squamous Cell Carcinomas in Our Department - Especially about 318 Tongue Carcinoma.

This clinico-statistical study includes 597 cases of oral squamous cell carcinoma treated at the Maxillofacial Surgery Section of Tokyo Medical and Dental University between January 2002 and December 2011. There were 373 male and 224 female patients (male to female ratio, 1.7 : 1), and the median age was 67 years. The tongue (53.3%) was the most commonly affected site. The 5-year disease-specific survival rate was 84.8%. Survival rates by clinical stage were as follows : Stage 1, 92.1% (n=195).; Stage , 86.0% (n = 221) ; Stage III, 77.7% (n=65) ; and Stage IV, 73.8% (n =116). Survival rates by primary site were as follows: tongue, 85.4% (n=318) ; lower gingiva, 82.8% (n =114) upper gingiva, 83.7% (n=59) ; buccal mucosa, 89.1% (n 54) ; oral floor, 81.4% (n=49) ; and hard palate, 100% (n=3). According to clinical growth patterns of Stage I / I tongue cancer cases, the 5-year disease-specific survival rate was significantly higher for patients with the exophytic/superficial type (97.3%, n =173) than for those with the endophytic type (77.5%, n=145). Among Stage I/II tongue cancer cases, the corresponding survival rate was significantly higher for patients who had not previously undergone invasive treatments (n=201), such as tooth extraction, compared to those who had previously done so (n=54) (92.7% and 79.7%, respectively). In addition, the incidence of secondary cervical lymph node metastasis was significantly higher in patients who had previously undergone invasive treatments.

Amelioration of endotoxin-induced uveitis treated with an IκB kinase ß inhibitor in rats.

PURPOSE: Endotoxin-induced uveitis (EIU) is an animal model for acute ocular inflammation. Several substances play major roles in the development of inflammatory changes in EIU, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, and IL-6. These inflammatory cytokines trigger the degradation of IκB by activating IκB kinases (IKKs). Released nuclear factor kappaB (NFκB) subsequently translocates to the nucleus, where NFκB expresses its proinflammatory function. IMD-0354, N-(3,5-Bis-trifluoromethylphenyl)-5-chloro-2-hydroxybenzamide, selectively inhibits IKKß, particularly when induced by proinflammatory cytokines, such as TNF-α and IL-1ß. In the present study, we examined whether IKKß inhibition has therapeutic effects on EIU by using IMD-0354 and its prodrug IMD-1041. METHODS: Six-week-old male Lewis rats were used. EIU was induced with subcutaneous injections of 200 µg of lipopolysaccharide (LPS) from Escherichia coli that had been diluted in 0.1 ml of phosphate-buffered saline. IMD-0354 was administered intraperitoneally at 30, 10, 3, or 0 mg/kg, suspended in 1.0 ml of 0.5% carboxymethyl cellulose sodium. The prodrug IMD-1041 (100 mg/kg) was also administered orally. The rats were euthanized 24 h after LPS injection, and EIU severity was evaluated histologically. The number of infiltrating cells and the protein, TNF-α, and monocyte chemoattractant protein-1 (MCP-1) concentrations in the aqueous humor were determined. TNF-α and MCP-1 concentrations were quantified with enzyme-linked immunosorbent assay. Eye sections were also stained with anti-NFκB and phosphorylated I-κBα antibodies. RESULTS: The number of infiltrating cells in aqueous humor was 53.6±9.8×10(5), 72.5±17.0×10(5), 127.25±32.0×10(5), and 132.0±25.0×10(5) cells/ml in rats treated with 30, 10, 3, or 0 mg/kg of IMD-0354, respectively. The total protein concentrations of aqueous humor were 92.6±3.1 mg/ml, 101.5±6.8 mg/ml, 112.6±1.9 mg/ml, and 117.33±1.8 mg/ml in rats treated with 30, 10, 3, and 0 mg/kg of IMD-0354, respectively. Infiltrating cells and protein concentrations were significantly decreased by treatment with IMD-0354 (p<0.01). IMD-0354 treatment significantly reduced the concentration of TNF-α (p<0.05) and MCP-1 (p<0.01) in aqueous humor. The number of NFκB positive nuclei was reduced when treated with IMD-0354. Furthermore, IMD-0354-treated EIU rats showed only background levels of phosphorylated I-κBα; however, it was strongly expressed in the iris-ciliary body cell cytoplasm of the IMD-0354 untreated EIU rats. Oral administration of IMD-1041 also decreased the cell number (p<0.01) and protein concentration (p<0.05) of aqueous humor in EIU. CONCLUSIONS: Acute uveitis was ameliorated by inhibition of IKKß in rats. IMD-0354 and its prodrug IMD-1041 seem to be promising candidates for treating intraocular inflammation/uveitis.

Prediction of ligand binding affinity using a multiple-conformations-multiple-protonation scheme: application to estrogen receptor α.

A fast method that can predict the binding affinities of chemicals to a target protein with a high degree of accuracy will be very useful in drug design and regulatory science. We have been developing a scoring function for affinity prediction, which can be applied to extensive protein systems, and also trying to generate a prediction scheme that specializes in each target protein, with as high a predictive power as possible. In this study, we have constructed a prediction scheme with target-specific scores for estimating ligand-binding affinities to human estrogen receptor α (ERα), considering the major conformational change between agonist- and antagonist-bound forms and the change in protonation states of histidine at the ligand-binding site. The generated scheme calibrated with fewer training compounds (23 for the agonist-bound form, 17 for the antagonist-bound form) demonstrated good predictive power (a predictive r(2) of 0.83 for 154 validation compounds); this was also true for compounds with frameworks that were quite different from those of the training compounds. Our prediction scheme will be useful in drug development targeting ERα and in primary screening of endocrine disruptors, and provides a successful method of affinity prediction considering the major conformational changes in a protein.

Starting point to molecular design: efficient automated 3D model builder Key3D.

Obtaining three-dimensional (3D) structures from structural formulae is a crucial process in molecular design. We have developed a new 3D model builder, Key3D, in which the simplified distance geometry technique and structure optimization based on the MMFF force field are combined. In an evaluation study using 598 crystal structures, the high performance and accuracy of Key3D were demonstrated. In the "flexible-fitting" test, which is focused on practical usefulness in the molecular design process, 88% of the Key3D structures acceptably reproduced the reference crystal structures (root-mean-square deviation <0.6 A) upon rotation of acyclic bonds. These results indicate that Key3D will be very effective in providing starting points for practical molecular design.

Effective handling of induced-fit motion in flexible docking.

For structure-based drug design, where various ligand structures need to be docked to a target protein structure, a docking method that can handle conformational flexibility of not only the ligand, but also the protein, is indispensable. We have developed a simple and effective approach for dealing with the local induced-fit motion of the target protein, and implemented it in our docking tool, ADAM. Our approach efficiently combines the following two strategies: a vdW-offset grid in which the protein cavity is enlarged uniformly, and structure optimization allowing the motion of ligand and protein atoms. To examine the effectiveness of our approach, we performed docking validation studies, including redocking in 18 test cases and foreign-docking, in which various ligands from foreign crystal structures of complexes are docked into a target protein structure, in 22 cases (on five target proteins). With the original ADAM, the correct docking modes (RMSD < 2.0 A) were not present among the top 20 models in one case of redocking and four cases of foreign-docking. When the handling of induced-fit motion was implemented, the correct solutions were acquired in all 40 test cases. In foreign-docking on thymidine kinase, the correct docking modes were obtained as the top-ranked solutions for all 10 test ligands by our combinatorial approach, and this appears to be the best result ever reported with any docking tool. The results of docking validation have thus confirmed the effectiveness of our approach, which can provide reliable docking models even in the case of foreign-docking, where conformational change of the target protein cannot be ignored. We expect that this approach will contribute substantially to actual drug design, including virtual screening.

Efficient method for high-throughput virtual screening based on flexible docking: discovery of novel acetylcholinesterase inhibitors.

A method of easily finding ligands, with a variety of core structures, for a given target macromolecule would greatly contribute to the rapid identification of novel lead compounds for drug development. We have developed an efficient method for discovering ligand candidates from a number of flexible compounds included in databases, when the three-dimensional (3D) structure of the drug target is available. The method, named ADAM&EVE, makes use of our automated docking method ADAM, which has already been reported. Like ADAM, ADAM&EVE takes account of the flexibility of each molecule in databases, by exploring the conformational space fully and continuously. Database screening has been made much faster than with ADAM through the tuning of parameters, so that computational screening of several hundred thousand compounds is possible in a practical time. Promising ligand candidates can be selected according to various criteria based on the docking results and characteristics of compounds. Furthermore, we have developed a new tool, EVE-MAKE, for automatically preparing the additional compound data necessary for flexible docking calculation, prior to 3D database screening. Among several successful cases of lead discovery by ADAM&EVE, the finding of novel acetylcholinesterase (AChE) inhibitors is presented here. We performed a virtual screening of about 160 000 commercially available compounds against the X-ray crystallographic structure of AChE. Among 114 compounds that could be purchased and assayed, 35 molecules with various core structures showed inhibitory activities with IC(50) values less than 100 microM. Thirteen compounds had IC(50) values between 0.5 and 10 microM, and almost all their core structures are very different from those of known inhibitors. The results demonstrate the effectiveness and validity of the ADAM&EVE approach and provide a starting point for development of novel drugs to treat Alzheimer's disease.