A covalent fragment-based strategy targeting a novel cysteine to inhibit activity of mutant EGFR kinase.

Several generations of ATP-competitive anti-cancer drugs that inhibit the activity of the intracellular kinase domain of the epidermal growth factor receptor (EGFR) have been developed over the past twenty years. The first-generation of drugs such as gefitinib bind reversibly and were followed by a second-generation such as dacomitinib that harbor an acrylamide moiety that forms a covalent bond with C797 in the ATP binding pocket. Resistance emerges through mutation of the T790 gatekeeper residue to methionine, which introduces steric hindrance to drug binding and increases the Km for ATP. A third generation of drugs, such as osimertinib were developed which were effective against T790M EGFR in which an acrylamide moiety forms a covalent bond with C797, although resistance has emerged by mutation to S797. A fragment-based screen to identify new starting points for an EGFR inhibitor serendipitously identified a fragment that reacted with C775, a previously unexploited residue in the ATP binding pocket for a covalent inhibitor to target. A number of acrylamide containing fragments were identified that selectively reacted with C775. One of these acrylamides was optimized to a highly selective inhibitor with sub-1 µM activity, that is active against T790M, C797S mutant EGFR independent of ATP concentration, providing a potential new strategy for pan-EGFR mutant inhibition.

Comparison of therapeutic effects of mesenchymal stem cells derived from superficial and deep subcutaneous adipose tissues.

BACKGROUND: Fibrosis is a common histological feature in the process from chronic organ injury to organ failure. Chronic tissue injury causes inflammatory cell infiltration into the injured tissue. The persistence of this inflammatory cell infiltration leads to fibrosis and organ failure. Adipose-derived mesenchymal stem cells (ASCs) have received much attention as a regenerative therapeutic tool to prevent progression from organ injury to failure. Subcutaneous abdominal adipose tissue is divided into superficial and deep layers by a superficial fascia. Adipose tissue easily collected by liposuction is usually obtained from a deep layer, so ASCs derived from a deep layer are generally used for regenerative medicine. However, no research has been conducted to investigate differences in the therapeutic effects of ASCs from the superficial and deep layers (Sup-ASCs and Deep-ASCs, respectively). Therefore, we compared the therapeutic potencies of Sup-ASCs and Deep-ASCs. METHODS: ASCs were isolated from superficial and deep subcutaneous abdominal adipose tissues collected from patients who underwent breast reconstruction. We first compared cell characteristics, such as morphology, cell proliferation, cell surface markers, adipogenic and osteogenic differentiation, cell senescence markers, and expression of coagulation and anticoagulant factors between Sup-ASCs and Deep-ASCs. Furthermore, we compared their ability to promote polarization of M2 macrophages and to inhibit transforming growth factor (TGF)-ß/Smad signaling using THP-1 cells and TGF-ß1 stimulated HK-2 cells incubated with conditioned media from Sup-ASCs or Deep-ASCs. In in vivo experiments, after renal ischemia-reperfusion injury (IRI) procedure, Sup-ASCs or Deep-ASCs were injected through the abdominal aorta. At 21 days post-injection, the rats were sacrificed and their left kidneys were collected to evaluate fibrosis. Finally, we performed RNA-sequencing analysis of Sup-ASCs and Deep-ASCs. RESULTS: Sup-ASCs had greater proliferation and adipogenic differentiation compared with Deep-ASCs, whereas both ASC types had similar morphology, cell surface markers, senescence markers, and expression of coagulation and anticoagulant factors. Conditioned media from Sup-ASCs and Deep-ASCs equally promoted polarization of M2 macrophages and suppressed TGF-ß/Smad signaling. Moreover, administration of Sup-ASCs and Deep-ASCs equally ameliorated renal fibrosis induced by IRI in rats. RNA-sequencing analysis revealed no significant difference in the expression of genes involved in anti-inflammatory and anti-fibrotic effects between Sup-ASCs and Deep-ASCs. CONCLUSIONS: These results indicate that both Sup-ASCs and Deep-ASCs can be used effectively and safely as an intravascular ASC therapy for organ injury.

Age estimation using post-mortem computed tomography and fetal dental radiographic findings in an early to mid-pregnancy fetus: A case report.

Parameters for body size growth are essential to evaluate the relationship between fetal growth and accurate age estimation in forensics. Size values measured postmortem are also affected by the postmortem environment. On the contrary, when using hard tissue maturation criteria, age estimation remains unaffected by the degree of fetal preservation. In Japan, a fetus dying 12 weeks after pregnancy must be reported as a stillbirth. A Japanese stillborn infant buried without reporting to the authorities underwent a forensic autopsy. The gestational age was 4-5 months, based on the mother's description. The body was not fixed, and it was macerated and flattened along the sagittal plane; therefore it was difficult to correctly measure indicators involving soft tissue. The bone size and tooth development were evaluated using postmortem computed tomography (CT) images and intraoral radiography to estimate the age. Considering all the information, including age estimation based on bone sizes referenced in a Japanese study, calcified upper central incisors, we estimated fetal gestational age for our sample as 14-17 gestational weeks finally. However, there were discrepancies between age estimations based on bone size (20-25 gestational weeks, bone radiographic imaging standards; or 4-6 gestational months, an average of the extremity-bones by a Japanese study) and tooth development (14-17 gestational weeks). Deep discussions based on multiple indices with professionals should be applied to forensic age estimation since existing methods may be based on data for different races, use other measurement tools, or apply different sample conditions even if the targets are the same.

Dental radiographic information of term newborn babies within the first month: Analyzing five radiographic cases along with physical attributes in Japan.

BACKGROUND: Although dental radiography is a valuable tool for age estimation in forensic anthropology and odontology, very limited radiological data are available regarding tooth development in healthy newborn babies during the first month of life. AIM: This study aimed to describe the radiological findings of tooth development in babies aged 0 days to 1 month. DESIGN: We analyzed the postmortem findings of five newborn babies with no known natural cause of death who had undergone autopsy, computed tomography (CT), and dental radiography. We estimated the gestational age for the babies aged 0 days and analyzed the condition of mandibular symphysis, existence of tooth germs, and presence or absence of calcification of the first permanent molars of all the babies. RESULTS: The calcified form of 20 deciduous teeth, tooth germs of the permanent upper and lower first molars, and non-calcified mandibular symphysis were observed in each case. However, calcification of the first permanent molar was observed in only two 1-month-old babies. CONCLUSION: The dental radiographic findings and anthropometric measurements of non-skeletonized, non-mummified term babies confirmed calcification of all the deciduous teeth and the first permanent molar at the age of 0 days and 1 month, respectively.

Four cases of cytokine storm after COVID-19 vaccination: Case report.

The global coronavirus disease 2019 (COVID-19) pandemic has led to the rapid development of vaccines against this disease. Despite the success of the international vaccination program, adverse events following vaccination, and the mechanisms behind them, remain poorly understood. Here we present four cases of death following receipt of a second dose of COVID-19 vaccine, with no obvious cause identified at autopsy. Using RNA sequencing, we identified genes that were differentially expressed between our post-vaccination cases and a control group that died of blood loss and strangulation. Three hundred and ninety genes were found to be upregulated and 115 genes were downregulated in post-vaccination cases compared with controls. Importantly, genes involved in neutrophil degranulation and cytokine signaling were upregulated. Our results suggest that immune dysregulation occurred following vaccination. Careful observation and care may be necessary if an abnormally high fever exceeding 40°C occurs after vaccination, even with antipyretic drugs.

Novel LCAT (Lecithin:Cholesterol Acyltransferase) Activator DS-8190a Prevents the Progression of Plaque Accumulation in Atherosclerosis Models.

OBJECTIVE: Enhancement of LCAT (lecithin:cholesterol acyltransferase) activity has possibility to be beneficial for atherosclerosis. To evaluate this concept, we characterized our novel, orally administered, small-molecule LCAT activator DS-8190a, which was created from high-throughput screening and subsequent derivatization. We also focused on its mechanism of LCAT activation and the therapeutic activity with improvement of HDL (high-density lipoprotein) functionality. Approach and Results: DS-8190a activated human and cynomolgus monkey but not mouse LCAT enzymes in vitro. DS-8190a was orally administered to cynomolgus monkeys and dose dependently increased LCAT activity (2.0-fold in 3 mg/kg group on day 7), resulting in HDL cholesterol elevation without drastic changes of non-HDL cholesterol. Atheroprotective effects were then evaluated using Ldl-r KO×hLcat Tg mice fed a Western diet for 8 weeks. DS-8190a treatment achieved significant reduction of atherosclerotic lesion area (48.3% reduction in 10 mg/kg treatment group). Furthermore, we conducted reverse cholesterol transport study using Ldl-r KO×hLcat Tg mice intraperitoneally injected with J774A.1 cells loaded with [3H]-cholesterol and confirmed significant increases of [3H] count in plasma (1.4-fold) and feces (1.4-fold on day 2 and 1.5-fold on day3) in the DS-8190a-treated group. With regard to the molecular mechanism involved, direct binding of DS-8190a to human LCAT protein was confirmed by 2 different approaches: affinity purification by DS-8190a-immobilized beads and thermal shift assay. In addition, the candidate binding site of DS-8190a in human LCAT protein was identified by photoaffinity labeling. CONCLUSIONS: This study demonstrates the potential of DS-8190a as a novel therapeutic for atherosclerosis. In addition, this compound proves that a small-molecule direct LCAT activator can achieve HDL-C elevation in monkey and reduction of atherosclerotic lesion area with enhanced HDL function in rodent.

U.S. Phase I First-in-human Study of Taletrectinib (DS-6051b/AB-106), a ROS1/TRK Inhibitor, in Patients with Advanced Solid Tumors.

PURPOSE: Taletrectinib (DS-6051b/AB-106) is an oral, tyrosine kinase inhibitor of ROS1 and NTRK with potent preclinical activity against ROS1 G2032R solvent-front mutation among others. We report the first-in-human U.S. phase I results of taletrectinib. PATIENTS AND METHODS: Patients ≥18 years old with neuroendocrine tumors, with tumor-induced pain, or tumors harboring ROS1/NTRK rearrangements were eligible. Accelerated titration followed by modified continuous reassessment method and escalation with overdose control was used (50-1,200 mg once daily or 400 mg twice daily). Primary objectives were safety/tolerability, and MTD determination. Secondary objectives were food-effect pharmacokinetics and antitumor activity. RESULTS: A total of 46 patients were enrolled. Steady-state peak concentration (C max) and exposure (AUC0-8) increased dose dependently from 50-mg to 800-mg once-daily doses. The ratio of the geometric mean of AUC0-24 between low-fat-diet-fed/fasted state was 123% (90% confidence interval, 104%-149%). Dose-limiting toxicities (grade 3 transaminases increase) occurred in two patients (1,200-mg once-daily dose). MTD was 800 mg once daily. Most common treatment-related adverse events were nausea (47.8%), diarrhea (43.5%), and vomiting (32.6%). Pain score reductions were observed in the 800-mg once-daily dose cohort. Confirmed objective response rate was 33.3% among the six patients with RECIST-evaluable crizotinib-refractory ROS1+ NSCLC. One patient with TPM3-NTRK1 differentiated thyroid cancer achieving a confirmed partial response of 27 months at data cutoff. We identified a cabozantinib-sensitive ROS1 L2086F as an acquired taletrectinib-resistance mutation. CONCLUSIONS: Taletrectinib has manageable toxicities at the MTD of 800 mg daily. Preliminary efficacy was observed in patients with crizotinib-refractory ROS1+ NSCLC.

The new-generation selective ROS1/NTRK inhibitor DS-6051b overcomes crizotinib resistant ROS1-G2032R mutation in preclinical models.

ROS1 gene rearrangement was observed in around 1-2 % of NSCLC patients and in several other cancers such as cholangiocarcinoma, glioblastoma, or colorectal cancer. Crizotinib, an ALK/ROS1/MET inhibitor, is highly effective against ROS1-rearranged lung cancer and is used in clinic. However, crizotinib resistance is an emerging issue, and several resistance mechanisms, such as secondary kinase-domain mutations (e.g., ROS1-G2032R) have been identified in crizotinib-refractory patients. Here we characterize a new selective ROS1/NTRK inhibitor, DS-6051b, in preclinical models of ROS1- or NTRK-rearranged cancers. DS-6051b induces dramatic growth inhibition of both wild type and G2032R mutant ROS1-rearranged cancers or NTRK-rearranged cancers in vitro and in vivo. Here we report that DS-6051b is effective in treating ROS1- or NTRK-rearranged cancer in preclinical models, including crizotinib-resistant ROS1 positive cancer with secondary kinase domain mutations especially G2032R mutation which is highly resistant to crizotinib as well as lorlatinib and entrectinib, next generation ROS1 inhibitors.

Identification of the 5,5-dioxo-7,8-dihydro-6H-thiopyrano[3,2-d]pyrimidine derivatives as highly selective PDE4B inhibitors.

A PDE4B subtype selective inhibitor is expected to have a wider therapeutic window than non-selective PDE4 inhibitors. In this Letter, two series of 7,8-dihydro-6H-thiopyrano[3,2-d]pyrimidine derivatives and 5,5-dioxo-7,8-dihydro-6H-thiopyrano[3,2-d]pyrimidine derivatives were evaluated for their PDE4B subtype selectivity using human PDE4B2 and PDE4D2 full length enzymes. To improve their PDE4B selectivity over PDE4D, we optimized the substituents on the pyrimidine ring and the side chain phenyl ring, resulting in several derivatives with more than 100-fold selectivity for PDE4B. Consequently, we identified 2-(3-chloro-4-methoxy-phenyl)-5,5-dioxo-7,8-dihydro-6H-thiopyrano[3,2-d]pyrimidine derivative 54 as a highly selective PDE4B inhibitor, which had potent hPDE4B inhibitory activity with an IC50 value of 3.0 nM and 433-fold PDE4B selectivity over PDE4D.

Reassessment of the unique mode of binding between angiotensin II type 1 receptor and their blockers.

While the molecular structures of angiotensin II (Ang II) type 1 (AT1) receptor blockers (ARBs) are very similar, they are also slightly different. Although each ARB has been shown to exhibit a unique mode of binding to AT1 receptor, different positions of the AT1 receptor have been analyzed and computational modeling has been performed using different crystal structures for the receptor as a template and different kinds of software. Therefore, we systematically analyzed the critical positions of the AT1 receptor, Tyr(113), Tyr(184), Lys(199), His(256) and Gln(257) using a mutagenesis study, and subsequently performed computational modeling of the binding of ARBs to AT1 receptor using CXCR4 receptor as a new template and a single version of software. The interactions between Tyr(113) in the AT1 receptor and the hydroxyl group of olmesartan, between Lys(199) and carboxyl or tetrazole groups, and between His(256) or Gln(257) and the tetrazole group were studied. The common structure, a tetrazole group, of most ARBs similarly bind to Lys(199), His(256) and Gln(257) of AT1 receptor. Lys(199) in the AT1 receptor binds to the carboxyl group of EXP3174, candesartan and azilsartan, whereas oxygen in the amidecarbonyl group of valsartan may bind to Lys(199). The benzimidazole portion of telmisartan may bind to a lipophilic pocket that includes Tyr(113). On the other hand, the n-butyl group of irbesartan may bind to Tyr(113). In conclusion, we confirmed that the slightly different structures of ARBs may be critical for binding to AT1 receptor and for the formation of unique modes of binding.

Synthesis and biological evaluation of 5-carbamoyl-2-phenylpyrimidine derivatives as novel and potent PDE4 inhibitors.

5-Carbamoyl-2-phenylpyrimidine derivative 2 has been identified as a phosphodiesterase 4 (PDE4) inhibitor with moderate PDE4B inhibitory activity (IC50=200 nM). Modification of the carboxylic acid moiety of 2 gave N-neopentylacetamide derivative 10f, which had high in vitro PDE4B inhibitory activity (IC50=8.3 nM) and in vivo efficacy against lipopolysaccharide (LPS)-induced pulmonary neutrophilia in mice (ID50=16 mg/kg, ip). Furthermore, based on the X-ray crystallography of 10f bound to the human PDE4B catalytic domain, we designed 7,8-dihydro-6H-pyrido[4,3-d]pyrimidin-5-one derivative 39 which has a fused bicyclic lactam scaffold. Compound 39 exhibited excellent inhibitory activity against LPS-induced tumor necrosis factor alpha (TNF-α) production in mouse splenocytes (IC50=0.21 nM) and in vivo anti-inflammatory activity against LPS-induced pulmonary neutrophilia in mice (41% inhibition at a dose of 1.0 mg/kg, i.t.).

Identification of the fused bicyclic 4-amino-2-phenylpyrimidine derivatives as novel and potent PDE4 inhibitors.

2-Phenyl-4-piperidinyl-6,7-dihydrothieno[3,4-d]pyrimidine derivative (2) was found to be a new PDE4 inhibitor with moderate PDE4B activity (IC50=150 nM). A number of derivatives with a variety of 4-amino substituents and fused bicyclic pyrimidines were synthesized. Among these, 5,5-dioxo-7,8-dihydro-6H-thiopyrano[3,2-d]pyrimidine derivative (18) showed potent PDE4B inhibitory activity (IC50=25 nM). Finally, N-propylacetamide derivative (31b) was determined as a potent inhibitor for both PDE4B (IC50=7.5 nM) and TNF-α production in mouse splenocytes (IC50=9.8 nM) and showed good in vivo anti-inflammatory activity in the LPS-induced lung inflammation model in mice (ID50=18 mg/kg). The binding mode of the new inhibitor (31e) in the catalytic site of PDE4B is presented based on an X-ray crystal structure of the ligand-enzyme complex.

[Living situation of the in-home patients suffering from amyotrophic lateral sclerosis in Aichi prefecture, Japan].

It is essential that we know the real situation of at-home patients with amyotrophic lateral sclerosis (ALS) in order to improve their medical support system. We indirectly investigated the daily living status of ALS patients and their families at home by conducting on individual questionnaires survey for nurses working at public health centers in Aichi prefecture, Japan. Detailed information about 136 cases was obtained, and we could clarify the need for variety of communication methods, plasticity of medical interrelations and care between neurologists and home doctors, incomplete utilization of social resources including various official support, overwork among single caregivers, and underdeveloped immature individual medical care support programs for them. Thus it might be important that we should promote the sure utilization of social resources and programming the individual medical care support in their earlier stages. And moreover, we should also consider constructing a general support system for at-home patients with ALS, in which each professional would owe the dividing responsibility, without role duplications. These strategies would lead to overall the better quality of life among ALS patients, and their families.

Small molecules with similar structures exhibit agonist, neutral antagonist or inverse agonist activity toward angiotensin II type 1 receptor.

Small differences in the chemical structures of ligands can be responsible for agonism, neutral antagonism or inverse agonism toward a G-protein-coupled receptor (GPCR). Although each ligand may stabilize the receptor conformation in a different way, little is known about the precise conformational differences. We synthesized the angiotensin II type 1 receptor blocker (ARB) olmesartan, R239470 and R794847, which induced inverse agonism, antagonism and agonism, respectively, and then investigated the ligand-specific changes in the receptor conformation with respect to stabilization around transmembrane (TM)3. The results of substituted cysteine accessibility mapping studies support the novel concept that ligand-induced changes in the conformation of TM3 play a role in stabilizing GPCR. Although the agonist-, neutral antagonist and inverse agonist-binding sites in the AT(1) receptor are similar, each ligand induced specific conformational changes in TM3. In addition, all of the experimental data were obtained with functional receptors in a native membrane environment (in situ).

[A case of intravascular malignant lymphomatosis presenting as slowly progressive paraplegia].

We present a case of a 62-year-old female was admitted with complaints of slowly developing paraplegia ascending from the distal portions, and a 7-month history of recto-urinary dysfunction. T2-weighted magnetic resonanse imaging (MRI) of the spinal cord showed hyperintense lesions in the thoracic and sacral cord. Multiple sclerosis was assumed, and steroid pulse therapy was therefore administered: this temporarily improved the symptoms and imaging findings. However, the symptoms recurred in 2 months. The patient died after ineffective steroid therapy. Large B-cell lymphoma cells were identified on bone marrow biopsy. Macroscopic neuropathology revealed neoplastic cells in the blood vessels of the cauda equina. Paraplegia appeared to have developed slowly and in a non-stepwise manner, since the cauda equina has been gradually invaded by intravascular malignant lymphomatosis.

Clinical and genetic characterizations of 16q-linked autosomal dominant spinocerebellar ataxia (AD-SCA) and frequency analysis of AD-SCA in the Japanese population.

Autosomal dominant spinocerebellar ataxias (AD-SCAs) form a clinically and genetically heterogeneous group of neurodegenerative disorders. Recently, a single nucleotide substitution in the 5'-untranslated region of the puratrophin-1 gene was found to be associated with one type of AD-SCA linked to chromosome 16q (16q-SCA). To obtain further insight into the contribution of the C-to-T substitution in the puratrophin-1 gene to the clinical and genetic characteristics of patients with 16q-SCA, we analyzed 686 families with 719 individuals diagnosed with progressive ataxia. We found C-to-T substitution in the puratrophin-1 gene in 57 unrelated families with 65 affected individuals. The mean age at onset in the patients with 16q-SCA was 59.1 (range, 46-77). Ataxia is the most common initial symptom. The elderly patients over 65 occasionally showed other accompanying clinical features including abnormalities in tendon reflexes, involuntary movements, and reduced vibration sense. We also examined the frequency of the AD-SCA subtype, considering the effects of age at onset. In the 686 AD-SCA families, SCA6 and Machado-Joseph disease/SCA3 are frequent subtypes, followed by dentatorubral-pallidoluysian atrophy and 16q-SCA. 16q-SCA is not a rare subtype of Japanese AD-SCA, particularly in patients with ages at onset over 60.

Multiple endocrine neoplasia type I and Cushing's syndrome due to an aggressive ACTH producing thymic carcinoid.

Thymic carcinoid in multiple endocrine neoplasia type 1 (MEN 1) is previously reported as a non-ACTH producing tumor. The present case is a 39-year-old man with mortal outcome from thymic carcinoid and Cushing's syndrome with high plasma ACTH. The symptom was first observed at age 29 and was relieved after extended thymectomy, with reduction of ACTH level. The tumor was positive for ACTH, Grimelius silver staining and Chromogranin A. The finding of primary hyperparathyroidism, pituitary adenoma, and a novel germline nonsense mutation (W423X) established the diagnosis of MEN 1. Cushing's syndrome due to ACTH producing thymic carcinoid should be also considered as one phenotype of the MEN 1 spectrum.

Growth hormone insensitivity syndrome associated with syringomyelia and type I Chiari malformation.

A 49-year-old man with syringomyelia and a Type I Arnold-Chiari malformation (Chiari-I) was diagnosed with growth hormone insensitivity syndrome (GHIS). He was short in stature, had high circulating levels of GH, and low circulating levels of insulin-like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3). His GH responses to the administration of growth hormone-releasing hormone (GHRH) and L-DOPA were normal, but his levels of IGF-I and IGFBP-3 did not increase after the administration of exogenous GH. Direct genomic DNA sequencing revealed neither a mutation nor deletion in this patient's GH receptor (GHR) gene, though one polymorphism was detected, indicating that his GHR gene was normal. This is the first reported case of an association of GHIS with syringomyelia and Chiari-I malformation.