The elucidation of species-specific receptor pharmacology: a case study using subtype selective para- and meta-carborane estrogen receptor agonists.

Estrogen receptors are essential pharmacological targets for treating hormonal disorders and estrogen-dependent malignancies. Selective activation of estrogen receptor (ER) ß is hypothesized to provide therapeutic benefit with reduced risk of unwanted estrogenic side-effects associated with ERα activity. However, activating ERß without activating α is challenging due to the high sequence and structural homology between the receptor subtypes. We assessed the impact of structural modifications to the parent compound OSU-ERß-12 on receptor subtype binding selectivity using cell-free binding assays. Functional selectivity was evaluated by transactivation in HEK-293 cells overexpressing human or murine estrogen receptors. In vivo selectivity was examined through the uterotrophic effects of the analogs after oral administration in estrogen-naïve female mice. Furthermore, we evaluated the in vivo pharmacokinetics of the analogs following single dose IV and oral administration. Regarding selectivity, a single compound exhibited greater functional selectivity than OSU-ERß-12 for human ERß. However, like others in the meta-carborane series, its poor in vivo pharmacokinetics limit its suitability for further development. Surprisingly, and at odds with their pharmacokinetic and in vitro human activity data, most analogs potently induced uterotrophic effects in estrogen-naïve female mice. Further investigation of activity in HEK293 cells expressing murine estrogen receptors revealed species-specific differences in the ER-subtype selectivity of these analogs. Our findings highlight species-specific receptor pharmacology and the challenges it poses to characterizing developmental therapeutics in preclinical species. Significance Statement This study investigates para- and meta-substituted carborane analogs targeting estrogen receptors, revealing the greater selectivity of carborane analogs for human ERß compared to the mouse homolog. These findings shed light on the intricacies of using preclinical species in drug development to predict human pharmacology. The report also provides insights for the refinement and optimization of carborane analogs as potential therapeutic agents for estrogen-related disease states.

Real-world application of comprehensive genomic profiling for gynecological malignancies: a multicenter observational study.

BACKGROUND: The actual status of comprehensive genomic profiling (CGP) applications in Japan has not been clarified. We conducted a multicenter study to investigate the real-world application of CGP in gynecological malignancies. METHODS: Nine designated cancer hospitals participated in this study. Patients who underwent CGP in 2020-2021 were assigned to the CGP group (n = 134). For the population that would have been eligible for CGP, patients who received initial treatment in 2015-2016 and were either alive with disease or died of disease at 5 years follow up were included in the control group (n = 316). We compared clinicopathological characteristics including tumor type (cervix, corpus, ovary, and others including sarcoma) and age. We also investigated the context of CGP-recommended treatment. RESULTS: The CGP group had significantly fewer cervical cases and more others cases (cervix/corpus/ovary/others: CGP, 22/44/56/12; control, 89/79/142/6; p = 0.0003). The CGP group was significantly younger than the control group (median: CGP, 54.0; control, 65.0; p < 0.0001). Subgroup analyses revealed that patients with cervical and ovarian cancers were significantly younger in the CGP group. Among the CGP group, 17 patients (12.7%) received CGP-recommended treatments, 15 of which were not covered by public insurance. The survival time after CGP in 17 patients was longer than in the other 117 cases (median 21 vs. 11 months). CONCLUSION: There was significant selection bias in tumor type and age for the application of CGP for gynecological malignancies in clinical practice in Japan. While CGP often recommended drugs not covered by public insurance, prognosis can be improved by use of CGP.

Ultra-fast One-Handed Helix Induction and Its Static Helicity Memory in a Poly(biphenylylacetylene) with a Catalytic Amount of Chiral Ammonium Salts.

We report an ultra-fast helix induction and subsequent static helicity memory in poly(biphenylylacetylene) (PBPA-A) assisted by a catalytic amount of nonracemic ammonium salts comprised of non-coordinating tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF- ) as a counter anion. The remarkable acceleration of the helix-induction rate in PBPA-A accompanied by the significant amplification of the asymmetry relies on the two methoxymethoxy groups of the biphenyl pendants, which can gain access to enfold the chiral ammoniums in a crown-ether manner in specific aromatic solvents, leading to ultra-fast helicity induction, which is completed within 30 s. In aromatic solvents, helicity memory is lost rapidly, but is quite stable in long-chain hydrocarbons. The best use of specific solvents for helicity induction and static helicity memory, respectively, provides a highly sensitive chirality sensing system toward a small amount of chiral amines and amino acids when complexed with BArF- .

Evaluation of foot ulcer incidence in diabetic patients at a diabetic foot ulcer prevention clinic over a 10-year period.

The present study aimed to evaluate diabetes patients over a 10-year period that visited our outpatient clinic for prevention of diabetic foot ulcers and then investigate the incidence and aetiology of diabetic foot ulcers. The Department of Diabetes and Metabolic Diseases of a university hospital was in charge of the clinic that provided diabetes patients with individual education via the use of visualisation techniques. In this prospective cohort study, a total of 942 diabetes patients who visited the clinic were evaluated for neuropathy, angiopathy and medical history between November 2006 and March 2017. Using the patients' medical records, diabetic foot ulcer development was evaluated between the day of the first visit and December 31, 2018, with 20 out of 942 participants developing these ulcers. Over a period of 12, 60 and 120 months, the diabetic foot ulcer cumulative incidence was 0.2%, 2.4% and 5.8%, respectively. A history of diabetic foot ulcers and the male sex were shown by a Cox regression analysis to be correlated with diabetic foot ulcer development (Hazard Ratio [HR] 11.55, 95%CI 4.600-29.004, p < 0.001; and HR 3.55, 95%CI 1.031-12.196, p = 0.045, respectively). However, only five out of 20 participants with ulceration returned to the clinic for re-examination. In conclusion, a 12-month evaluation showed there was a low incidence of diabetic foot ulcers. These results might suggest that patients with a diabetic foot ulcer history need to undergo at least an annual follow-up in order to further reduce diabetic foot ulcer incidence, although studies involving control groups needs to be conducted, in presenting these as evidence.

Association Between Anxiety and Depressive Symptoms During Prehospitalization Waiting Period and Quality of Recovery at Postoperative Day 3 in Perioperative Cancer Patients.

PURPOSE: Perioperative depressive symptoms are associated with poor postoperative quality of life (QOL), leading to prolonged hospital stays, and delayed return to society. Previous studies show that physical and mental states change on the third day after surgery, and there is a correlation between quality of recovery (QoR) on this day and QOL at 3 months after surgery. QoR after surgery is an important indicator of postoperative QOL. However, there are no reports on the association between depressive symptoms, and postoperative QoR. Therefore, the study purpose was to clarify the relationship between depressive symptoms in perioperative cancer patients during the prehospitalization waiting period, and QoR on the third postoperative day. DESIGN: This was a prospective cohort study. METHODS: We examined whether depressive symptoms during the prehospitalization waiting period were related to QoR on day 3 after surgery in perioperative cancer patients. Subjects were patients with primary tumors who underwent surgery under general anesthesia. Subjects completed self-administered questionnaires during the prehospitalization waiting period and on postoperative day 3. The presence and/or absence of depressive symptoms was measured using the Hospital Anxiety and Depression Scale. Subjects were divided into two groups: depressive symptoms or non-depressive symptoms. Postoperative QoR was determined using the QoR-40 questionnaire and we calculated the rate of change in QoR-40 global and dimension scores from preoperation to postoperation. FINDINGS: 231 individuals met the inclusion criteria and agreed to participate in the study. Of these, 173 were included in the analysis. Only the rate of change in emotional state differed significantly between groups (P = .022). Both global and dimension QoR-40 scores were lower in the depressive symptoms group than in the non-depressive symptoms group. CONCLUSIONS: These findings demonstrate the need to provide both psychological and physical support continuously from the preoperative to early postoperative stage for cancer patients with depressive symptoms in the prehospitalization waiting period.

Vacuolar H+-Pyrophosphatase and Cytosolic Soluble Pyrophosphatases Cooperatively Regulate Pyrophosphate Levels in Arabidopsis thaliana.

Inorganic pyrophosphate (PPi) is a phosphate donor and energy source. Many metabolic reactions that generate PPi are suppressed by high levels of PPi. Here, we investigated how proper levels of cytosolic PPi are maintained, focusing on soluble pyrophosphatases (AtPPa1 to AtPPa5; hereafter PPa1 to PPa5) and vacuolar H+-pyrophosphatase (H+-PPase, AtVHP1/FUGU5) in Arabidopsis thaliana In planta, five PPa isozymes tagged with GFP were detected in the cytosol and nuclei. Immunochemical analyses revealed a high abundance of PPa1 and the absence of PPa3 in vegetative tissue. In addition, the heterologous expression of each PPa restored growth in a soluble PPase-defective yeast strain. Although the quadruple knockout mutant plant ppa1 ppa2 ppa4 ppa5 showed no obvious phenotypes, H+-PPase and PPa1 double mutants (fugu5 ppa1) exhibited significant phenotypes, including dwarfism, high PPi concentrations, ectopic starch accumulation, decreased cellulose and callose levels, and structural cell wall defects. Altered cell arrangements and weakened cell walls in the root tip were particularly evident in fugu5 ppa1 and were more severe than in fugu5 Our results indicate that H+-PPase is essential for maintaining adequate PPi levels and that the cytosolic PPa isozymes, particularly PPa1, prevent increases in PPi concentrations to toxic levels. We discuss fugu5 ppa1 phenotypes in relation to metabolic reactions and PPi homeostasis.

A cell-wall protein SRPP provides physiological integrity to the Arabidopsis seed.

Seed and root hair protective protein (SRPP) is expressed in seeds and root hairs, localized in the cell wall, and involved in cell wall integrity. We analyzed a loss-of-function mutant of SRPP, focusing on siliques and seeds. The srpp-1 plants generated dark brown shrunken seeds at a high rate. The germination rate of these defect seeds of srpp-1 was less than 6%, although apparently normal srpp-1 seeds germinated at a rate of 83%. The production ratio of severe phenotypic seeds was dependent on the growth conditions. When the srpp-1 plants were cultivated at low humidity, the defect ratio was 73%, which was significantly higher than that at normal humidity. Defects of the silique and seeds could be detected on day 7 after pollination and the apical region of the siliques displayed a severe phenotype at a high frequency. Complementation with an SRPP gene under the control of promoters specific to the embryo, seed coat, or valve (carpel) partially rescued the phenotype, and complementation using the SRPP promoter fully rescued the phenotype. Furthermore, overexpression of SRPP enhanced the thermotolerance. After the treatment of seeds at 50 °C for 2 h, the germination rate of the seeds from overexpression with the 35S promoter increased to levels twice that of the wild-type seeds. Under the same conditions, no srpp-1 seeds germinated. These results indicate that SRPP is essential for the production of normal viable seeds in siliques under stress conditions. It is possible that modification of the SRPP gene improves seed integrity.

Biochemical, Structural and Physiological Characteristics of Vacuolar H+-Pyrophosphatase.

Proton-translocating inorganic pyrophosphatase (H+-PPase) actively translocates protons across membranes coupled with the hydrolysis of inorganic pyrophosphate (PPi). H+-PPase, which is composed of a single protein and uses a simple compound as a substrate, has been recognized as a new type of ion pump in addition to the P-, F- and V-type ion-translocating ATPases. H+- and Na+-PPases are distributed in various organisms including plants, parasitic protozoa, Archaebacteria and bacteria, but are not present in animals or yeast. Vacuolar H+-PPase has dual functions in plant cells: hydrolysis of cytosolic PPi to maintain the levels of PPi, and translocation of protons into vacuoles to maintain the acidity of the vacuolar lumen. Acidification performed with the vacuolar-type H+-ATPase and H+-PPase is essential to maintain acidic conditions, which are necessary for vacuolar hydrolytic enzymes and for supplying energy to secondary active transporters. Recent studies using loss-of-function mutant lines of H+-PPase and complementation lines with soluble PPases have emphasized the physiological importance of the scavenging role of PPi. An overview of the main features of H+-PPases present in the vacuolar membrane is provided in terms of tissue distribution in plants, intracellular localization, structure-function relationship, biochemical potential as a proton pump and functional stability.

Clinical significance of initial symptoms in endometriosis-associated ovarian cancer.

Objective: Endometriosis is associated with various symptoms, but their severity varies from case to case. In this study, we investigated the reality of symptoms presented by patients with clinically early-stage endometriosis-associated ovarian cancer (EAOC) and explored the relationship between symptoms and laboratory/imaging findings, pathological findings, and prognosis. Materials and Methods: This was a retrospective case-control study of patients who received initial surgical treatment and were diagnosed with clinically early-stage EAOC, including ovarian endometrioid carcinoma (OEC), ovarian clear cell carcinoma (OCCC), and seromucinous borderline tumor (SMBT). Patients with OEC/OCCC diagnosed between 2006 and 2016 and those with SMBT diagnosed between 2006 and 2020 were included. Chi-square and Kaplan-Meier estimates were used for statistical analyses. Results: One hundred-seven patients (OEC, n=31; OCCC, n=39; SMBT, n=37) were included. Fifty-nine (55.1%) patients presented with symptoms, and the proportion of patients with OEC who presented with symptoms was significantly higher than that of others (OEC, 77.4%; OCCC, 43.6%; SMBT, 48.6%). The details of symptoms differed significantly among the pathological types (lower abdominal pain/abdominal discomfort/abnormal bleeding, OEC: 11/8/9; OCCC: 6/12/1; SMBT: 15/5/3). Only in the OEC group did symptomatic patients show significantly higher white blood cell (WBC) count and neutrophil/lymphocyte (N/L) ratio (symptomatic vs. asymptomatic, median: WBC count: 7250 vs. 5000, p=0.008; N/L ratio: 4.6 vs. 1.7, p=0.013). None of the asymptomatic patients showed recurrence during follow-up. Conclusion: Patients with EAOC show varying symptoms depending on the histological type of the tumor. Laboratory findings underlying symptoms also vary by histopathological type, which may reflect differences in the carcinogenesis process.

Development of an inducible excision system of a visual marker Ipomoea batatas Myb gene from the genome of transgenic cells.

In the plant genetic transformation process, single selection by a chemical-resistant marker gene occasionally allows the proliferation of non-transgenic cells, escaping selection pressure. The additional use of a visual marker gene is effective for accurate selection. For instance, R2R3-MYB genes are used for regulating anthocyanin biosynthesis; however, constitutive Myb expression in transgenic plants is not always desirable and may cause developmental abnormalities due to excess anthocyanin accumulation. To overcome the remaining problems in the use of Myb as a visible marker, we developed T-DNA. Ipomoea batatas Myb (IbMyb) and Cre expression cassettes were inserted between two loxP sequences, and the hygromycin phosphotransferase (HPT) and green fluorescent protein (GFP) expression cassettes were located outside of the loxP-IbMyb-Cre-loxP region. In the developed system, IbMyb and Cre were excised from the genomes of transgenic cells using heat-inducible Cre-loxP recombination. Upon heat treatment in a general incubator, green shoots emerged from purple tobacco transgenic calli that were pigmented with IbMyb expression. The excision of IbMyb from the genome of green shoots was confirmed using polymerase chain reaction (PCR) and sequencing. GFP expression was observed in the roots of the obtained green transgenic plants. We report that the system developed here operated successfully in tobacco, showing the potential to provide an easier and cheaper visual selection of transgenic cells in the genetic transformation process.

Why and by How Much is Insulin Absorption Reduced by Insulin-derived Amyloidosis? A Scoping Review.

Insulin therapy is one of the central treatments for diabetes mellitus. Insulin-derived localized amyloidosis (IDLA) is a known skin-related complication of insulin injection. This is one of the causes of poor glycemic control in diabetic patients on insulin therapy. The aim of this study was to review and update the findings on the extent and mechanism of reduced insulin absorption in IDLA. A literature search was conducted on decreased insulin absorption and its mechanisms, and nine references were selected, with seven of these on decreased insulin absorption and four on mechanisms. Insulin absorption at IDLA sites was reported to be 27-94% lower compared with normal sites. In addition, a comparison between nonpalpable and palpable IDLA sites revealed a significant decrease in insulin absorption at the palpable IDLA site. The mechanism of insulin malabsorption was found to be a reduction in insulin absorption at the palpable IDLA sites. Four mechanisms of decreased insulin absorption were identified: decreased subcutaneous blood flow, adsorption of administered insulin onto insulin amyloid fibers, impaired diffusion of insulin subcutaneously, and physical factors such as shaking of the insulin preparation. These mechanisms should be investigated in vivo in the future.

Impact of diabetes and Krebs von den Lungen-6 on coronavirus disease 2019 severity: A single-center study from Japan.

AIMS/INTRODUCTION: Diabetes mellitus is reported as a risk factor for increased coronavirus disease 2019 (COVID-19) severity and mortality, but there have been few reports from Japan. Associations between diabetes mellitus and COVID-19 severity and mortality were investigated in a single Japanese hospital. MATERIALS AND METHODS: Patients aged ≥20 years admitted to Osaka City General Hospital for COVID-19 treatment between April 2020 and March 2021 were included in this retrospective, observational study. Multivariable logistic regression analysis was carried out to examine whether diabetes mellitus contributes to COVID-19-related death and severity. RESULTS: Of the 262 patients included, 108 (41.2%) required invasive ventilation, and 34 (13.0%) died in hospital. The diabetes group (n = 92) was significantly older, more obese, had longer hospital stays, more severe illness and higher mortality than the non-diabetes group (n = 170). On multivariable logistic regression analysis, age (odds ratio [OR] 1.054, 95% confidence interval [CI] 1.023-1.086), body mass index (OR 1.111, 95% CI 1.028-1.201), history of diabetes mellitus (OR 2.429, 95% CI 1.152-5.123), neutrophil count (OR 1.222, 95% CI 1.077-1.385), C-reactive protein (OR 1.096, 95% CI 1.030-1.166) and Krebs von den Lungen-6 (OR 1.002, 95% CI 1.000-1.003) were predictors for COVID-19 severity (R2 = 0.468). Meanwhile, age (OR 1.104, 95% CI 1.037-1.175) and Krebs von den Lungen-6 (OR 1.003, 95% CI 1.001-1.005) were predictors for COVID-19-related death (R2 = 0.475). CONCLUSIONS: Diabetes mellitus was a definite risk factor for COVID-19 severity in a single Japanese hospital treating moderately-to-severely ill patients.

Lack of Vacuolar H+ -Pyrophosphatase and Cytosolic Pyrophosphatases Causes Fatal Developmental Defects in Arabidopsis thaliana.

The cytosolic level of inorganic pyrophosphate (PPi) is finely regulated, with PPi hydrolyzed primarily by the vacuolar H+-pyrophosphatase (H+-PPase, VHP1/FUGU5/AVP1) and secondarily by five cytosolic soluble pyrophosphatases (sPPases; PPa1-PPa5) in Arabidopsis thaliana. Loss-of-function mutants of H+-PPase (fugu5s) have been reported to show atrophic phenotypes in their rosette leaves when nitrate is the sole nitrogen source in the culture medium. For this phenotype, two questions remain unanswered: why does atrophy depend on physical contact between shoots and the medium, and how does ammonium prevent such atrophy. To understand the mechanism driving this phenotype, we analyzed the growth and phenotypes of mutants on ammonium-free medium in detail. fugu5-1 showed cuticle defects, cell swelling, reduced ß-glucan levels, and vein malformation in the leaves, suggesting cell wall weakening and cell lethality. Based on the observation in the double mutants fugu5-1 ppa1 and fugu5-1 ppa4 of more severe atrophy compared to fugu5-1, the nitrogen-dependent phenotype might be linked to PPi metabolism. To elucidate the role of ammonium in this process, we examined the fluctuations of sPPase mRNA levels and the possibility of alternative PPi-removing factors, such as other types of pyrophosphatase. First, we found that both the protein and mRNA levels of sPPases were unaffected by the nitrogen source. Second, to assess the influence of other PPi-removing factors, we examined the phenotypes of triple knockout mutants of H+-PPase and two sPPases on ammonium-containing medium. Both fugu5 ppa1 ppa2 and fugu5 ppa1 ppa4 had nearly lethal embryonic phenotypes, with the survivors showing striking dwarfism and abnormal morphology. Moreover, fugu5 ppa1+/- ppa4 showed severe atrophy at the leaf margins. The other triple mutants, fugu5 ppa1 ppa5 and fugu5 ppa2 ppa4, exhibited death of root hairs and were nearly sterile due to deformed pistils, respectively, even when grown on standard medium. Together, these results suggest that H+-PPase and sPPases act in concert to maintain PPi homeostasis, that the existence of other PPi removers is unlikely, and that ammonium may suppress the production of PPi during nitrogen metabolism rather than stimulating PPi hydrolysis.

Macromolecular helicity control of poly(phenyl isocyanate)s with a single stimuli-responsive chiral switch.

The introduction of a single chiral substituent with a switchable conformer equilibrium at the poly(phenyl isocyanate) terminus allowed the control of the helical sense of the polymer backbone using various external stimuli. Helical sense enhancement was achieved through a domino effect, where the helical sense was assigned by VCD spectroscopy and DFT calculations.

Lack of H(+)-pyrophosphatase Prompts Developmental Damage in Arabidopsis Leaves on Ammonia-Free Culture Medium.

The plant vacuolar H(+)-pyrophosphatase (H(+)-PPase) functions as a proton pump coupled with the hydrolysis of pyrophosphate (PPi). Loss-of-function mutants (fugu5s and vhp1) of the H(+)-PPase of Arabidopsis thaliana show clear morphological phenotypes in the cotyledons, caused by inhibition of gluconeogenesis from seed storage lipids due to excessive accumulation of PPi. In this study, we investigated the phenotypes of the fugu5 and vhp1 mutants during vegetative growth under a specific nitrogen nutritional regime. When nitrate in the culture medium was the sole nitrogen source, growth of the mutant rosette leaves was severely compromised. Interestingly, trypan blue staining revealed notable cell death at the leaf blade-petiole junctions of young leaves, a region known to have meristematic features. Physical contact of the leaf tip with the culture medium also triggered leaf atrophy, suggesting that absorption of some elements through the hydathodes was probably involved in this phenotype. Prevention of such leaf-medium contact resulted in a marked decrease in phosphate content in the shoots, and suppressed leaf atrophy. Furthermore, fugu5 necrotic symptoms were rescued completely by heterologous expression of yeast cytosolic soluble pyrophosphatase IPP1 or uncoupling-type H(+)-PPases that retained only PPi-hydrolysis activity, indicating that the damage of actively proliferating cells was caused by the loss of the PPi-hydrolyzing function of H(+)-PPase. Importantly, cell death and growth defects of the fugu5 leaves were suppressed completely by the simple addition of ammonium (>1 mM) to the culture medium. The PPi content in the shoots of fugu5 grown on ammonium-free medium was 70% higher than that of the wild type, and PPi levels were restored to normal upon growth on ammonium-supplemented medium. Together, these findings suggest that the PPi-hydrolyzing activity of H(+)-PPase is essential to maintain the PPi contents at optimal levels when grown on ammonium-free culture medium, and any direct contact of the leaves with the culture medium may raise PPi levels in the leaves through increased phosphate uptake.

Effects of novel small compounds targeting TrkB on neuronal cell survival and depression-like behavior.

Brain-derived neurotrophic factor (BDNF) and its high affinity receptor tyrosine kinase receptor B (TrkB) are involved in neuronal survival, maintenance, differentiation and synaptic plasticity. Deficiency of BDNF was reported to be associated with psychological disorders such as depression. Hence we examined proliferative effect of 11 candidate TrkB agonistic compounds in TrkB-expressing SH-SY5Y cells, via a hypothesis that some candidate compounds identified in our previous in silico screening for a small molecule targeting the BDNF binding domain of TrkB should activate TrkB signaling. In the present study, two promising compounds, 48 and 56, were identified and subsequently assessed for their ability to induce TrkB phosphorylation in vitro and in vivo. Likewise those seen in BDNF, the compounds mediated TrkB phosphorylation was blocked by the Trk inhibitor, K252a. Since BDNF-TrkB signaling deficiency is associated with the pathogenesis of depression and reactivation of this signaling by antidepressants is a cause of the pathogenic state recovery, the compounds were subjected to the assessment for forced swim test, which is a mouse model of depression. We found that compound 48 significantly reduced mouse immobility time compared with the control vehicle injection, suggesting the confirmation of hypothetical antidepressant-like efficacy of 48 compound in vivo. Thus, our present study demonstrated that compound 48, selected through in silico screening, is a novel activator of TrkB signaling and a potential antidepressant molecule.

Identification of novel candidate compounds targeting TrkB to induce apoptosis in neuroblastoma.

Neuroblastoma (NB) is one of the most frequent solid tumors in children and its prognosis is still poor. The neurotrophin receptor TrkB and its ligand brain-derived neurotrophic factor (BDNF) are expressed at high levels in high-risk NBs and are involved in defining the poor prognosis of the patients. However, the TrkB targeting therapy has never been realized in the clinic. We performed an in silico screening procedure utilizing an AutoDock/grid computing technology in order to identify novel small chemical compounds targeting the BDNF-binding domain of TrkB. For the first screening, a library of three million synthetic compounds was screened in silico and was ranked according to the Docking energy. The top-ranked 37 compounds were further functionally screened for cytotoxicity by using NB cell lines. We have finally identified seven compounds that kill NB cells with the IC50 values of 0.07-4.6 µmol/L. The terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay showed that these molecules induce apoptosis accompanied by p53 activation in NB cell lines. The candidate compounds and BDNF demonstrated an antagonistic effect on cell growth, invasion, and colony formation, possibly suggesting competition at the BDNF-binding site of TrkB. The candidate compounds had tumor-suppressive activity in xenograft and in vivo toxicity tests (oral and intravenous administrations) using mice, and did not show any abnormal signs. Using in silico Docking screening we have found new candidate TrkB inhibitors against high-risk NBs, which could lead to new anti-cancer drugs.