Novel recombinant human thyroid-stimulating hormone in aiding postoperative assessment of patients with differentiated thyroid cancer-phase I/II study.

PURPOSE: Thyroid hormone withdrawal (THW) inevitably induced hypothyroidism in patients with differentiated thyroid cancer (DTC), and we aimed to evaluate the safety and efficacy of a novel recombinant human thyroid-stimulating hormone (rhTSH, ZGrhTSH) as an alternative of THW in China. METHODS: Totally, 64 DTC patients were enrolled with 24 in the dose-escalation cohort equally grouped into 0.9 mg × 1 day, 0.9 mg × 2 day, 1.8 mg × 1 day, and 1.8 mg × 2 day dosage, and 40 further enrolled into 0.9 mg × 2 day dose-expansion cohort. All patients underwent both ZGrhTSH phase and levothyroxine (L-T4) withdrawal phase for self-comparison in terms of TSH levels, the radioactive iodine (RAI) uptake, stimulated thyroglobulin level, and the quality of life (QoL). RESULTS: In ZGrhTSH phase, no major serious adverse events were observed, and mild symptoms of headache were observed in 6.3%, lethargy in 4.7%, and asthenia in 3.1% of the patients, and mostly resolved spontaneously within 2 days. Concordant RAI uptake was noticed in 89.1% (57/64) of the patients between ZGrhTSH and L-T4 withdrawal phases. The concordant thyroglobulin level with a cut-off of 1 µg/L was noticed in 84.7% (50/59) of the patients without the interference of anti-thyroglobulin antibody. The QoL was far better during ZGrhTSH phase than L-T4 withdrawal phase, with lower Billewicz (- 51.30 ± 4.70 vs. - 39.10 ± 16.61, P < 0.001) and POMS (91.70 ± 16.70 vs. 100.40 ± 22.11, P = 0.011) scores which indicate the lower the better. Serum TSH level rose from basal 0.11 ± 0.12 mU/L to a peak of 122.11 ± 42.44 mU/L 24 h after the last dose of ZGrhTSH. In L-T4 withdrawal phase, a median of 23 days after L-T4 withdrawal was needed, with the mean TSH level of 82.20 ± 31.37 mU/L. The half-life for ZGrhTSH clearance was about 20 h. CONCLUSION: The ZGrhTSH held the promise to be a safe and effective modality in facilitating RAI uptake and serum thyroglobulin stimulation, with better QoL of patients with DTC compared with L-T4 withdrawal.

Novel Tetrahydropyrido[4,3-d]pyrimidines as Potent Inhibitors of Chaperone Heat Shock Protein 90.

Heat shock protein 90 (Hsp90) is a potential target for oncology therapeutics. Some inhibitors have shown antitumor effects in clinical trials, spurring the discovery of small molecule Hsp90 inhibitors. Here, we describe the structural optimization studies of a hit compound, tetrahydropyrido[4,3-d]pyrimidine-based Hsp90 inhibitor 15, which exhibits inhibitory activity against Hsp90. A series of analogues were synthesized, and their structure-activity and structure-property relationships were analyzed. These explorations led to the discovery of compound 73, which exhibited potent in vitro activities, good physicochemical properties, favorable ADME properties, and a potent antitumor effect in an HCT116 xenograft model. Furthermore, 73 exhibited no ocular toxicity in a rat retinal damage model, suggesting it is a relatively safe Hsp90 inhibitor. As a promising antitumor agent, 73 was progressed for further preclinical evaluation.

CPUY201112, a novel synthetic small-molecule compound and inhibitor of heat shock protein Hsp90, induces p53-mediated apoptosis in MCF-7 cells.

Heat-shock protein 90 (Hsp90) is highly expressed in many tumor cells and is associated with the maintenance of malignant phenotypes. Targeting Hsp90 has had therapeutic success in both solid and hematological malignancies, which has inspired more studies to identify new Hsp90 inhibitors with improved clinical efficacy. Using a fragment-based approach and subsequent structural optimization guided by medicinal chemistry principles, we identified the novel compound CPUY201112 as a potent Hsp90 inhibitor. It binds to the ATP-binding pocket of Hsp90 with a kinetic dissociation (Kd) constant of 27 ± 2.3 nM. It also exhibits potent in vitro antiproliferative effects in a range of solid tumor cells. In MCF-7 cells with high Hsp90 expression, CPUY201112 induces the degradation of Hsp90 client proteins including HER-2, Akt, and c-RAF. We prove that treating MCF-7 cells with CPUY201112 results in cell cycle arrest and apoptosis through the wild-type (wt) p53 pathway. CPUY201112 also synergizes with Nutlin-3a to induce cancer cell apoptosis. CPUY201112 significantly inhibited the growth of MCF-7 xenografts in nude mice without apparent body weight loss. These results demonstrate that CPUY201112 is a novel Hsp90 inhibitor with potential use in treating wild-type p53 related cancers.

Identification and optimization of novel Hsp90 inhibitors with tetrahydropyrido[4,3-d]pyrimidines core through shape-based screening.

Rapid Overlay of Chemical Structures (ROCS), which can rapidly identify potentially active compounds by shape comparison, is recognized as a powerful virtual screening tool. By ROCS, a class of novel Hsp90 inhibitors was identified. The calculated binding mode of the most potent hit 36 guided us to design and synthesize a series of analogs (57a-57h). Over 100-fold improvement was achieved in the target-based assay. The most potent compound 57h inhibited Hsp90 with IC50 0.10 ± 0.01 µM. It also showed much improved cell potency and ligand efficiency. Our study showed that ROCS is efficient in the identification of novel cores of Hsp90 inhibitors. 57h can be ideal leads for further optimization.

Synthesis and evaluation of a novel class Hsp90 inhibitors containing 1-phenylpiperazine scaffold.

Previously, we identified 1-(2-(4-bromophenoxy)ethoxy)-3-(4-(2-methoxyphenyl)piperazin-1-yl)propan-2-ol (1) as a novel Hsp90 inhibitor with moderate activity through virtual screening. In this study, we report the optimization process of 1. A series of analogues containing the 1-phenylpiperazine core scaffold were synthesized and evaluated. The structure-activity relationships (SAR) for these compounds was also discussed for further molecular design. This effort afforded the most active inhibitor 13f with improved activity in not only target-based level, but also cell-based level compared with the original hit 1.

Discovery and Bioevaluation of Novel Pyrazolopyrimidine Analogs as Competitive Hsp90 Inhibitors Through Shape-Based Similarity Screening.

Hsp90 as a promising therapeutic target for the treatment of cancer has received great attention. Many Hsp90 inhibitors such as BIIB021 and CUDC-305 have been in clinical. In this paper shape-based similarity screening through ROCS overlays on the basis of CUDC-305, BIIB021, PU-H71 and PU-3 were performed to discover HSP90 inhibitors. A set of 19 novel pyrazolopyrimidine analogues was identified and evaluated on enzyme level and cell-based level as Hsp90 inhibitors. The compound HDI4-04 with IC50 0.35 µM in the Hsp90 ATP hydrolysis assay exhibited potent cytotoxicity against five human cancer cell lines. Western blot analysis and Hsp70 luciferase reporter assay further confirmed that HDI4-04 targeted the Hsp90 protein folding machinery. And according to the biological assay, the SAR was discussed and summarized, which will guide us for further optimization of these compounds.

Hybrids of the Benzofuran Core from Natural Products and the 2,4-Dihydroxy-5-isopropylbenzene Fragment as Potent Hsp90 Inhibitors: Design, Synthesis and Bioevaluation.

Several chemical fragments have been confirmed as highly efficient cores for the design of Hsp90 inhibitors. Molecular hybridization of potent fragments has been widely used as a rational drug discovery strategy. In this study, a novel class of hybrids of benzofuran, a privileged core from natural products, and 2,4-dihydroxy-5-isopropyl phenyl, an efficient fragment in Hsp90 inhibitors, were designed and synthesized. Subsequent evaluation confirmed they inhibited cell proliferation and regulated the level of client proteins through Hsp90 inhibition. Some of the hybrids can serve as leads to obtain novel chemotypes of Hsp90 inhibitors. The methods reported here may expand the range of known structural types accommodated by the ATP binding site of Hsp90.

3-aroylmethylene-2,3,6,7-tetrahydro-1H-pyrazino[2,1-a]isoquinolin-4(11bH)-ones as potent Nrf2/ARE inducers in human cancer cells and AOM-DSS treated mice.

Nrf2-mediated activation of ARE regulates expression of cytoprotective enzymes against oxidative stress, inflammation, and carcinogenesis. We have discovered a novel structure (1) as an ARE inducer via luciferase reporter assay to screen the in-house database of our laboratory. The potency of 1 was evaluated by the expression of NQO-1, HO-1, and nuclear translocation of Nrf2 in HCT116 cells. In vivo potency of 1 was studied using AOM-DSS models, showing that the development of colorectal adenomas was significantly inhibited. Administration with 1 lowered the expression of IL-6, IL-1ß, and promoted Nrf2 nuclear translocation. These results indicated that 1 is a potent Nrf2/ARE activator, both in vitro and in vivo. Forty-one derivatives were synthesized for SAR study, and a more potent compound 17 was identified. To our knowledge, this is a potent ARE activator. Besides, its novel structure makes it promising for further optimization.

Insight into the intermolecular recognition mechanism between Keap1 and IKKß combining homology modelling, protein-protein docking, molecular dynamics simulations and virtual alanine mutation.

Degradation of certain proteins through the ubiquitin-proteasome pathway is a common strategy taken by the key modulators responsible for stress responses. Kelch-like ECH-associated protein-1(Keap1), a substrate adaptor component of the Cullin3 (Cul3)-based ubiquitin E3 ligase complex, mediates the ubiquitination of two key modulators, NF-E2-related factor 2 (Nrf2) and IκB kinase ß (IKKß), which are involved in the redox control of gene transcription. However, compared to the Keap1-Nrf2 protein-protein interaction (PPI), the intermolecular recognition mechanism of Keap1 and IKKß has been poorly investigated. In order to explore the binding pattern between Keap1 and IKKß, the PPI model of Keap1 and IKKß was investigated. The structure of human IKKß was constructed by means of the homology modeling method and using reported crystal structure of Xenopus laevis IKKß as the template. A protein-protein docking method was applied to develop the Keap1-IKKß complex model. After the refinement and visual analysis of docked proteins, the chosen pose was further optimized through molecular dynamics simulations. The resulting structure was utilized to conduct the virtual alanine mutation for the exploration of hot-spots significant for the intermolecular interaction. Overall, our results provided structural insights into the PPI model of Keap1-IKKß and suggest that the substrate specificity of Keap1 depend on the interaction with the key tyrosines, namely Tyr525, Tyr574 and Tyr334. The study presented in the current project may be useful to design molecules that selectively modulate Keap1. The selective recognition mechanism of Keap1 with IKKß or Nrf2 will be helpful to further know the crosstalk between NF-κB and Nrf2 signaling.

Synthesis and bioevaluation of a series of α-pyrone derivatives as potent activators of Nrf2/ARE pathway (part I).

When exposed to electrophiles, human colorectal cancer cells (HCT116) counteract oxidative stress through activating NF-E2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway. To identify new activators, luciferase reporter gene assay was used to screen in-house database of our laboratory, leading to a novel α-pyrone compound 1 as a hit. 2 with 2-fluoro phenyl group exhibited the strongest ARE inductive activity in the first round structure-activity relationship (SAR) study. Biological studies showed the compound induced nuclear translocation of Nrf2 preceded by phosphorylation of ERK1/2. The data encouraged us to use 2 as lead and 20 derivatives were synthesized to discuss a more detailed SAR, leading to a more potent compound 9, which can be the starting compound for further modification.

Novel IKKß inhibitors discovery based on the co-crystal structure by using binding-conformation-based and ligand-based method.

IκB kinase ß (IKKß), an attractive anti-inflammation and anti-cancer target, plays a crucial role in the activation of NF-κB signalling pathway. To identify novel IKKß inhibitors, we combined structure-based and ligand-based methods based on the co-crystal structure of IKKß. According to the chemical similarity, 162 reported IKKß inhibitors were divided into five classes. For each class, a 3D pharmacophore model was established based on the binding conformations of the compounds. The validated models were further used in virtual screening. Twelve drugable compounds were retained for biological test, resulting in two novel inhibitors with IC50 values lower than 10 µM. Compared to other models, our method considers the crystal structure of IKKß for the first time.

Differential acetylcholine and choline concentrations in the cerebrospinal fluid of patients with Alzheimer's disease and vascular dementia.

BACKGROUND: An important aspect of Alzheimer's disease (AD) is loss or impairment of cholinergic neurons. It is controversial whether there is a similar cholinergic impairment and cerebral deficit of acetylcholine (ACh) in the case of vascular dementia (VD). The purpose of this study was to explore the levels of ACh and choline (Ch) in the cerebrospinal fluid (CSF) of patients with AD and VD, and their possible relationship with cognitive impairment. METHODS: Twenty-two AD patients, twenty-two VD patients, and twenty normal controls were recruited and scored with a Mini-Mental State Examination (MMSE). CSF concentrations of ACh and Ch were measured using high-performance liquid chromatography with an electrochemical detector (HPLC-ECD) and the results were then compared to cognitive status. RESULTS: ACh concentrations in CSF of AD patients [(10.7 +/- 5.1) nmol/L] and VD patients [(16.8 +/- 7.4) nmol/L] were both significantly lower than in controls [(34.5 +/- 9.0) nmol/L, t = 10.67, P < 0.001; t = 6.91, P < 0.001]. Both results correlated positively with MMSE scores (rs = 0.88 and rs = 0.85, respectively, P < 0.01). The CSF concentration of Ch was significantly higher in VD patients [(887.4 +/- 187.4) nmol/L] compared to AD patients [(627.6 +/- 145.1) nmol/L, t = 6.4, P < 0.001] and controls [(716.0 +/- 159.4) nmol/L, t = 4.2, P = 0.002]. CSF Ch concentration showed no difference between AD patients and normal controls, nor did it correlate with MMSE score in any of the three groups. CONCLUSIONS: The positive correlation between ACh deficit and cognitive impairment suggests that ACh is an important neurotransmitter for memory. The similar decrease in ACh concentration in AD and VD patients may imply a similar pathogenesis for the process of cognitive impairment involved in these two disorders. The elevated CSF levels of Ch in VD patients compared to AD patients may be useful diagnostically. Cholinesterase inhibitors may be helpful not only for AD patients, but also for VD patients.

[Relationship between learning ability and memory and free radical in hippocampus of old rats].

OBJECTIVE: To study the relationship between the amount of free radical in hippocampus and the learning ability and memory in old rats. METHODS: Morris water maze was used for 10 days to examine the learning scores, latency scores, and the loci of movement in the maze among 46 old rats (aged 20 months), 36 young rats (aged 6 months), and 34 adult rats (aged 12 months). Salicylate was injected intraperitoneally and hippocampus dialysis was performed. Chromatography was used to measure the basic values of 2,3DHBA and 2,5DHBA in dialysis fluid chemiluminometry was used to measure the superoxide dismutrase (SOD) in the sample. The rats were killed and their brains were taken out. Histological examination was conducted to calculate the number of neurons in CA1, CA4, and PM regions in hippocampus. RESULTS: The learning scores on the first, fifth, and tenth days were 36.5 +/- 5.9 sec, 38.6 +/- 5.9 sec, and 39.4 +/- 6.9 sec (P > 0.05) in the old rats; 60.2 +/- 5.4 sec, 156.8 +/- 5.8 sec, and 165.1 +/- 6.8 sec in the young rats; and 61.7 +/- 5.8 sec, 152.3 +/- 6.9 sec, and 168.7 +/- 6.5 sec in adult rats. The learning scores at any time point of old rats were significantly lower than those of the young and adults rats (all P < 0.01). The latency scores of the first, fifth, and tenth days were 25.7 +/- 1.2 sec, 27.5 +/- 1.9 sec, and 27.7 +/- 1.9 sec in the old rats without significant difference between any two of these values (P > 0.05), however, the 3 latency scores of the old rats were all significantly larger than those of the young and adult rats (21.8 +/- 1.7 sec, 5.9 +/- 1.0 sec, and 3.6 +/- 0.6 sec, and 21.8 +/- 1.6 sec, 5.0 +/- 0.9 sec, and 4.8 +/- 0.7 sec respectively, all P < 0.01). The basic value of 2,3DHBA after intraperitoneal injection of salicylate was 20.7 +/- 0.3 pmol/ml in the old rats, 5 times that of the young rats and 6 times that of the adult rats (P < 0.01). The basic value of 2,5DHBA after intraperitoneal injection of salicylate was 60.12 pmol/ml in the old rats, 6 times that of the young rats and 5.8 times that of the adult rats (P < 0.01). The SOD activity was 410 U x g(-1) x min(-1) +/- 50 U x g(-1) x min(-1), significantly lower than those in the young and adult rats (880 U x g(-1) x min(-1) +/- 62 U x g(-1) x min(-1) and 860 U x g(-1) x min(-1) +/- 60 U x g(-1) x min(-1) (both P < 0.01). The values of neuron density in CA1, CA4, and PM regions of the old rats were all significantly lower than those of the young and adult rats (all P < 0.01). CONCLUSION: The decrease of learning ability in old rat is positively correlated with the increase of free radicals and loss of neurons in hippocampus.