Optimization Efforts for Identification of Novel Highly Potent Keap1-Nrf2 Protein-Protein Interaction Inhibitors.

In research focused on protein-protein interaction (PPI) inhibitors, the optimization process to achieve both high inhibitory activity and favorable physicochemical properties remains challenging. Our previous study reported the discovery of novel and bioavailable Keap1-Nrf2 PPI inhibitor 8 which exhibited moderate in vivo activity in rats. In this work, we present our subsequent efforts to optimize this compound. Two distinct approaches were employed, targeting high energy water molecules and Ser602 as "hot spots" from the anchor with good aqueous solubility, metabolic stability, and membrane permeability. Through ligand efficiency (LE)-guided exploration, we identified two novel inhibitors 22 and 33 with good pharmacokinetics (PK) profiles and more potent in vivo activities, which appear to be promising chemical probes among the existing inhibitors.

Discovery and SAR of JTE-151: A Novel RORγ Inhibitor for Clinical Development.

A number of RORγ inhibitors have been reported over the past decade. There were also several examples advancing to human clinical trials, however, none of them has reached the market yet, suggesting that there could be common obstacles for their future development. As was expected from the general homology of nuclear receptor ligands, insufficient selectivity as well as poor physicochemical properties were identified as potential risks for a RORγ program. Based on such considerations, we conducted a SAR investigation by prioritizing drug-like properties to mitigate such potential drawbacks. After an intensive SAR exploration with strong emphasis on "drug-likeness" indices, an orally available RORγ inhibitor, JTE-151, was finally generated and was advanced to a human clinical trial. The compound was confirmed to possess highly selective profiles along with good metabolic stability, and most beneficially, no serious adverse events (SAE) and good PK profiles were observed in the human clinical trial.

Structure-based drug design of novel and highly potent pyruvate dehydrogenase kinase inhibitors.

Pyruvate dehydrogenase kinases (PDHKs) are fascinating drug targets for numerous diseases, including diabetes and cancers. In this report, we describe the result of our structure-based drug design from tricyclic lead compounds that led to the discovery of highly potent PDHK2 and PDHK4 dual inhibitors in enzymatic assay. The C3-position of the tricyclic core was explored, and the PDHK2 X-ray structure with a representative compound revealed a novel ATP lid conformation in which the phenyl ring of Phe326 mediated the interaction of the Arg258 sidechain and the compound. Compounds with amide linkers were designed to release the ATP lid by forming an intramolecular pi-pi interaction, and these compounds showed single-digit nM IC50 values in an enzymatic assay. We also explored the C4-position of the tricyclic core to reproduce the interaction observed with the C3-position substitution, and the pyrrolidine compound showed the same level of IC50 values. By optimizing an interaction with the Asn255 sidechain through a docking simulation, compounds with 2-carboxy pyrrole moiety also showed single-digit nM IC50 values without having a cation-pi interaction with the Arg258 sidechain.

Discovery of a Janus Kinase Inhibitor Bearing a Highly Three-Dimensional Spiro Scaffold: JTE-052 (Delgocitinib) as a New Dermatological Agent to Treat Inflammatory Skin Disorders.

Dermatologic disorders such as atopic dermatitis arise from genetic and environmental causes and are complex and multifactorial in nature. Among possible risk factors, aberrant immunological reactions are one of the leading etiologies. Immunosuppressive agents including topical steroids are common treatments for these disorders. Despite their reliability in clinical settings, topical steroids display side effects, typified by skin thinning. Accordingly, there is a need for alternate effective and well-tolerated therapies. As part of our efforts to investigate new immunomodulators, we have developed a series of JAK inhibitors, which incorporate novel three-dimensional spiro motifs and unexpectedly possess both excellent physicochemical properties and antidermatitis efficacy in the animal models. One of these compounds, JTE-052 (ent-60), also known as delgocitinib, has been shown to be effective and well-tolerated in human clinical trials and has recently been approved in Japan for the treatment of atopic dermatitis as the first drug among Janus kinase inhibitors.

Androgen deprivation therapy prevents bladder cancer recurrence.

Although accumulating preclinical evidence indicates the involvement of androgen receptor signals in bladder cancer (BC) development, its clinical relevance remains unclear. We aimed to evaluate the predictive role of androgen deprivation therapy (ADT) in BC recurrence in prostate cancer (PC) patients. We retrospectively reviewed 20,328 patients with PC diagnosed during 1991-2013 and identified 239 (1.2%) men having primary BC. After excluding ineligible patients, 162 patients made up a final cohort. With a median follow-up of 62 months, 38 (50%) of 76 control patients without ADT experienced BC recurrence, while 19 (22%) of 86 did in ADT group. Thus, patients having received ADT for their PC showed a significantly lower risk of BC recurrence (5-year actuarial recurrence-free survival: 76% v 40%; P < 0.001) and also had a significantly smaller number of recurrence episodes (5-year cumulative recurrence: 0.44 v 1.54; P < 0.001), compared to the control patients. A multivariable analysis revealed ADT as an independent prognosticator (hazard ratio, 0.29; 95% confidence interval, 0.17-0.49) for BC recurrence. This is the first clinical study showing that ADT significantly reduces the risk of BC recurrence.

Induction of extracytoplasmic function sigma factors in Bacillus subtilis cells with membranes of reduced phosphatidylglycerol content.

The Bacillus subtilis gene pgsA, which codes for the phosphatidylglycerophosphate synthase that catalyzes the committed step for the synthesis of phosphatidylglycerol (PG), is essential since Pspac-pgsA cells require IPTG for growth. Removal of the inducer caused a dramatic decrease of PG content in the membranes of cells and retarded growth. At 60 min and 120 min after removal, it was reduced to 14.1% and 8.9% of total lipid, respectively, from an initial content of 28.1%. We conjectured that the activity of some extracytoplasmic function (ECF) sigma factors, most of which are caught and regulated directly by cognate transmembrane anti-sigma factors, are affected by altered lipid composition of the membranes. Induction of the activities of ECF sigma factors (sigma(M) and sigma(V)) was observed after removal of IPTG, though that of sigma(V) was small. But other ECF sigma factors (sigma(W), sigma(X), sigma(Y), sigma(YlaC) and sigma(Z)) and the general stress sigmas sigma(B) and sigma(I) were not induced. Especially sigma(M) was activated strongly with the reduction of PG content and sustained a high level of activity, in contrast to the transient activation in PG normal cells after exposure to high salinity. This study demonstrates a new relationship between the alterations of lipid composition in the membranes and the activation of ECF sigma factors.

Involvement of PlsX and the acyl-phosphate dependent sn-glycerol-3-phosphate acyltransferase PlsY in the initial stage of glycerolipid synthesis in Bacillus subtilis.

The gene responsible for the first acylation of sn-glycerol-3-phosphate (G3P) in Bacillus subtilis has not yet been determined with certainty. The product of this first acylation, lysophosphatidic acid (LPA), is subsequently acylated again to form phosphatidic acid (PA), the primary precursor to membrane glycerolipids. A novel G3P acyltransferase (GPAT), the gene product of plsY, which uses acyl-phosphate formed by the plsX gene product, has recently been found to synthesize LPA in Streptococcus pneumoniae. We found that in B. subtilis growth arrests after repression of either a plsY homologue or a plsX homologue were overcome by expression of E. coli plsB, which encodes an acyl-acylcarrier protein (acyl-ACP)-dependent GPAT, although in the case of plsX repression a high level of plsB expression was required. B. subtilis has, therefore, a capability to use the acyl-ACP dependent GPAT of PlsB. Simultaneous expression of plsY and plsX suppressed the glycerol requirement of a strict glycerol auxotrophic derivative of the E. coli plsB26 mutant, although either one alone did not. Membrane fractions from B. subtilis cells catalyzed palmitoylphosphate-dependent acylation of [14C]-labeled G3P to synthesize [14C]-labeled LPA, whereas those from DeltaplsY cells did not. The results indicate unequivocally that PlsY is an acyl-phosphate dependent GPAT. Expression of plsX corrected the glycerol auxotrophy of a DeltaygiH (the deleted allele of an E. coli homologue of plsY) derivative of BB26-36 (plsB26 plsX50), suggesting an essential role of plsX other than substrate supply for acyl-phosphate dependent LPA synthesis. Two-hybrid examinations suggested that PlsY is associated with PlsX and that each may exist in multimeric form.

[Multi-center trial on the early effects of silodosin on lower urinary tract symptoms associated with benign prostatic hyperplasia].

Silodosin (URIEF), a new so-called 3rd generation alpha-1 blocker, is widely expected to be effective and useful for lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH), due to its high specificity to alpha-1A receptor. We evaluated the efficacy of Silodosin, on 187 males 50 years old or over with the diagnosis of BPH. Silodosin significantly improved the International Prostate Symptom Score (IPSS) and quality of life (QOL) score from the day after administration was started. Among 166 patients whose data were available for the analysis of efficacy of Silodosin, 77.5% showed apparent subjective improvement. Eighty three patients, who had been taking another alpha-1 blocker but without satisfactory effects, showed almost the same improvements in IPSS and QOL score after switching to Silodosin as the remaining 83 patients who had no preceding treatment with an alpha-1 blocker. The improvements were not only in voiding symptoms but also in storage symptoms. The patients, who had serious storage symptoms, responded rather well to Silodosin and showed significant improvement. Taken together, Silodosin showed a quick effect for improving subjective symptoms and QOL, and was found to be useful for the management of LUTS with BPH.

Further studies on hepatitis C virus NS5B RNA-dependent RNA polymerase inhibitors toward improved replicon cell activities: benzimidazole and structurally related compounds bearing the 2-morpholinophenyl moiety.

Following the discovery of JTK-109 (1) as a potent inhibitor of hepatitis C virus NS5B RNA-dependent RNA polymerase, [(a) Hirashima, S.; Suzuki, T.; Ishida, T.; Noji, S.; Yata, S.; Ando, I.; Komatsu, M.; Ikeda, S.; Hashimoto, H. J. Med. Chem.2006, 49, 4721. (b) Hashimoto, H.; Mizutani, K.; Yoshida, A. Int. Patent Appl. WO 01/47883, 2001.] further studies toward the improvement of the cellular potency have been performed. A greater than 40-fold improvement was achieved through replacing the biphenyl moiety with a 2-morpholinophenyl group and the benzimidazole ring with the tetracyclic scaffold to afford compound 7 with an excellent replicon potency (EC(50)=7.6 nM).

Discovery of conformationally constrained tetracyclic compounds as potent hepatitis C virus NS5B RNA polymerase inhibitors.

We report a new series of hepatitis C virus NS5B RNA polymerase inhibitors containing a conformationally constrained tetracyclic scaffold. SAR studies led to the identification of 6,7-dihydro-5H-benzo[5,6][1,4]diazepino[7,1-a]indoles (19 and 20) bearing a basic pendent group with high biochemical and cellular potencies. These compounds displayed a very small shift in cellular potency when the replicon assay was performed in the presence of human serum albumin.

[A case of small cell carcinoma of kidney; solitary splenic metastasis].

A 67-year-old male visited a hospital with a complaint of right flank pain. A computed tomography and magnetic resonance imaging demonstrated a right renal tumor, lymphadenopathy, and a splenic tumor. Right radical nephrectomy, lymph node dissection, and splenectomy were performed. Histological examination of the renal tumor and lymph node revealed small cell anaplastic carcinoma. A dilated renal pelvis was focally covered with transitional cell carcinoma grade 2. Splenic tumor revealed a mixture of small cell and giant cell anaplastic carcinoma. Immunostaining for NSE and cytokeratin were positive. He received 2 courses of adjuvant chemotherapy with cisplatin and etoposide. The patient is alive for 10 months after surgery and free of carcinoma. This is the 10th case of renal small cell carcinoma reported in Japan. The clinical features and managements of these rare tumors are discussed.

Acute scrotum caused by Henoch-Schönlein purpura.

A boy aged 3 years and 11 months with arthralgia and purpuric skin rash was diagnosed with Henoch-Schönlein purpura (HSP) following an acute occurrence of his scrotal pain and swelling 17 days after the appearance of arthralgia. Immediate scrotal exploration was performed to confirm vasculitis of the left epididymis compatible with a scrotal manifestation of HSP. Postoperative course was uneventful. Twenty-five cases of HSP with acute scrotum reported in Japan, including this case, are calculated and discussed.