Directing-Group-Free Arene C(sp2)-H Amination Using Bulky Aminium Radicals and DFT Analysis of Regioselectivity.

A hydroxylamine-derived electrophilic aminating reagent produces a transient and bulky aminium radical intermediate upon in situ activation by either TMSOTf or TFA and a subsequent electron transfer from an iron(II) catalyst. Density functional theory calculations were used to examine the regioselectivity of arene C-H amination reactions on diversely substituted arenes. The calculations suggest a simple charge-controlled regioselectivity model that enables prediction of the major C(sp2)-H amination product.

Synthesis and evaluation of multivalent nitroimidazole-based near-infrared fluorescent agents for neuroblastoma and colon cancer imaging.

Hypoxia is one of key characteristics of microenvironments of solid tumors, and evaluation of hypoxia status in solid tumors is important to determine cancer stage and appropriate treatment. In the present study, novel, multivalent, near-infrared (NIR) fluorescent imaging agents were developed to measure tumor hypoxia. These agents were synthesized using an amino acid as a backbone to connect mono-, bis-, or tris-2-nitroimidazole as a hypoxia-sensitive moiety to enhance uptake by the tumor and to attach sulfo-Cyanine 5.5 as an NIR fluorophore to visualize tumor accumulation. Studies of physical characteristics demonstrated that the novel NIR imaging agents showed suitable optical properties for in vitro and in vivo imaging and were stable in serum. In vitro cellular uptake studies in SK-N-BE(2) and SW620 cell lines demonstrated that NIR imaging agents bearing 2-nitroimidazole structures showed significantly higher tumor uptake in hypoxic cells than in normoxic cells. Moreover, in vivo optical imaging studies using SK-N-BE(2) and SW620 xenografted mice demonstrated that novel, multivalent, 2-nitroimadazole NIR imaging agents with two or three 2-nitroimidazole moieties showed higher uptake in tumor than the control agents with only one 2-nitroimidazole. These observations suggest that novel, multivalent, NIR agents could serve as potential optical imaging agents for evaluating tumor hypoxia.

Evaluation of the Inhibitory Effects of Pyridylpyrazole Derivatives on LPS-Induced PGE2 Productions and Nitric Oxide in Murine RAW 264.7 Macrophages.

A series of thirteen triarylpyrazole analogs were investigated as inhibitors of lipopolysaccharide (LPS)-induced prostaglandin E2 (PGE2) and nitric oxide (NO) production in RAW 264.7 macrophages. The target compounds 1a-m have first been assessed for cytotoxicity against RAW 264.7 macrophages to determine their non-cytotoxic concentration(s) for anti-inflammatory testing to make sure that the inhibition of PGE2 and NO production would not be caused by cytotoxicity. It was found that compounds 1f and 1m were the most potent PGE2 inhibitors with IC50 values of 7.1 and 1.1 µM, respectively. In addition, these compounds also showed inhibitory effects of 11.6% and 37.19% on LPS-induced NO production, respectively. The western blots analysis of COX-2 and iNOS showed that the PGE2 and NO inhibitory effect of compound 1m are attributed to inhibition of COX-2 and iNOS protein expression through inactivation of p38.

Synthesis and Evaluation of Multifunctional Fluorescent Inhibitors with Synergistic Interaction of Prostate-Specific Membrane Antigen and Hypoxia for Prostate Cancer.

Prostate cancer is one of the most common cancers in the world. It is widely known that prostate-specific membrane antigen (PSMA) is highly expressed in prostate cancer, and hypoxia is a common characteristic of many solid tumors, including prostate cancer. In this study, we designed multifunctional fluorescent inhibitors to target PSMA and tumor hypoxia in order to increase the tumor uptake of inhibitors. Novel PSMA inhibitors were prepared using lysine as the backbone to connect three different functional groups: the glutamate-urea-lysine (GUL) structure for inhibiting PSMA, 2-nitroimidazole for the hypoxia-sensitive moiety, and a near-infrared fluorophore (sulfo-Cyanine 5.5). According to the in vitro PSMA binding assay, novel fluorescent inhibitors were demonstrated to have nanomolar binding affinities. Multifunctional inhibitor 2 with one 2-nitroimidazole had a similar inhibitory activity to inhibitor 1 that did not contain the hypoxia targeting moiety, but multifunctional inhibitor 3 with two 2-nitroimidazoles showed lower inhibitory activity than inhibitor 1 due to the bulky structure of the hypoxia-sensitive group. However, in vivo optical imaging and ex vivo biodistribution studies indicated that both multifunctional inhibitors 2 and 3 had higher accumulation in tumors than inhibitor 1 due to a synergistic combination of PSMA and hypoxia targeting moieties. These observations suggest that this novel multifunctional strategy might be a promising approach to improve the diagnosis and therapy of prostate cancer.

Chemoselective Radiosyntheses of Electron-Rich [18F]Fluoroarenes from Aryl(2,4,6-trimethoxyphenyl)iodonium Tosylates.

Hypervalent diaryliodonium salts have been used to produce various [18F]fluoroarenes. The iodonium salt approach as a labeling precursor has been established to equally afford complex 18F-fluorinated molecules. Because of the inherent two aryl ring system connected to a central iodine atom, safeguarding the chemoselectivity during radiofluorination using diaryliodonium salts is important. Herein, we introduce a superior chemoselective radiosynthesis of [18F]fluoroarenes using an aryl(2,4,6-trimethoxyphenyl)iodonium tosylate as a precursor for 18F-incorporation, even on electron-rich aryl rings.

Synthesis and evaluation of novel potent TSPO PET ligands with 2-phenylpyrazolo[1,5-a]pyrimidin-3-yl acetamide.

Translocator protein (TSPO) expression is closely related with neuroinflammation and neuronal damage which might cause several central nervous system diseases. Herein, a series of TSPO ligands (11a-c and 13a-d) with a 2-phenylpyrazolo[1,5-a]pyrimidin-3-yl acetamide structure were prepared and evaluated via an in vitro binding assay. Most of the novel ligands exhibited a nano-molar affinity for TSPO, which was better than that of DPA-714. Particularly, 11a exhibited a subnano-molar TSPO binding affinity with suitable lipophilicity for in vivo brain studies. After radiolabeling with fluorine-18, [18F]11a was used for a dynamic positron emission tomography (PET) study in a rat LPS-induced neuroinflammation model; the inflammatory lesion was clearly visualized with a superior target-to-background ratio compared to [18F]DPA-714. An immunohistochemical examination of the dissected brains confirmed that the uptake location of [18F]11a in the PET study was consistent with a positively activated microglia region. This study proved that [18F]11a could be employed as a potential PET tracer for detecting neuroinflammation and could give possibility for diagnosis of other diseases, such as cancers related with TSPO expression.

Synthesis of novel multivalent fluorescent inhibitors with high affinity to prostate cancer and their biological evaluation.

Prostate-specific membrane antigen (PSMA) is an important biological target for therapy and diagnosis of prostate cancer. In this study, novel multivalent PSMA inhibitors with glutamate-urea-lysine structures were designed to improve inhibition characteristics. Precursors of the novel inhibitors were prepared from glutamic acid with di-tert-butyl ester. A near-infrared molecular dye, sulfo-Cy5.5, was introduced into the precursors to generate the final PSMA fluorescent inhibitors, compounds 12-14, to visualize prostate cancer. Biological behaviors of the inhibitors were evaluated using in vitro inhibition assays, in vivo fluorescent imaging, and ex vivo biodistribution assays. Ki values from inhibition studies indicated that dimeric inhibitor 13 with a glutamine linker showed approximately 3-fold more inhibitory activity than monomeric inhibitor 12. According to other biological studies using a mouse model of prostate cancer, dimeric inhibitor compounds 13 and 14 had higher tumor accumulation than the monomer. However, glutamine-based dimeric inhibitor 13 showed lower liver uptake than dimeric inhibitor 14, which had a benzene structure. Thus, these studies suggest that glutamine-based dimeric inhibitor 13 can be a promising optical inhibitor of prostate cancer.

18F-labelled BODIPY dye as a dual imaging agent: Radiofluorination and applications in PET and optical imaging.

Dual Positron emission tomography (PET)/optical imaging techniques have captured scientific interest for clinical applications due to their potential as an effective tool for visualizing in vivo information such as disease processes. 4,4'-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) dye has been considered an ideal platform strategy to achieve dual PET/optical imaging due to its photochemical nature and chemical structure. Various radiofluorination methods to prepare [18F]BODIPY dye have been developed and established, ranging from nucleophilic substitution reactions to isotope exchange reactions. In addition, 18F-labelled BODIPY dyes for biologically important targets have been used for in vivo and ex vivo studies. These studies proved the practicality of [18F]BODIPY dyes as a hybrid PET/optical imaging probe. In this review, recent advances in the synthesis and biological evaluation of 18F-labelled BODIPY dyes are described.

Late-Stage 18F/19F Isotopic Exchange for the Synthesis of 18F-Labeled Sulfamoyl Fluorides.

Synthesis of sulfamoyl [18F]fluorides has been a challenging topic owing to the inefficient nucleophilic radiofluorination of sulfamoyl derivatives. Herein, we report an 18F/19F isotopic exchange approach to synthesize various sulfamoyl [18F]fluorides, otherwise inaccessible via direct synthesis from amines, with high radiochemical yields up to 97% (30 examples). This late-stage labeling protocol offers an efficient route to yield functionalized molecules by diversifying the chemical library possessing sulfamoyl functionalities through nucleophilic 18F incorporation within nitrogen-containing sulfur(VI) frameworks.

Deregulation of miR-519a, 153, and 485-5p and its clinicopathological relevance in ovarian epithelial tumours.

AIMS: The pathological and clinical significance of aberrant miRNA expression in ovarian tumours has yet to be adequately documented. The aim of this study was to assess the differences in miRNA expression of human ovarian tumours according to histological subtype, and to determine whether miRNAs are potential diagnostic and prognostic markers in ovarian cancers. METHOD AND RESULTS: The miRNA expression profiles of 103 human ovarian tumours were evaluated. Via a bead-based miRNA microarray, five aberrant miRNAs were selected which were expressed differentially in malignant serous tumours from borderline and benign ovarian tumours, including miRNA (miR)-519a, miR-18b (up-regulation) and miR-153, miR-511 and miR-485-5p (down-regulation). We conducted quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) in order to confirm that these miRNAs are differentially expressed in different histological subtypes of ovarian tumours, and compared the expression profiles of these miRNAs between different clinical subsets. The expression of these miRNAs was correlated with clinicopathological parameters. miR-519a, miR-153 and miR-485-5p were differentially expressed in four major histotypes of ovarian cancers (P < 0.05), which suggests that they might be of potential importance as diagnostic biomarkers. Down-regulation of miR-153 and miR-485-5p was correlated significantly with FIGO grade 3 (P < 0.05). Down-regulation of miR-153 and up-regulation of miR-519a were correlated significantly with advanced clinical stage (P < 0.05). The results of Kaplan-Meier survival analysis indicated that the higher expression of miR-519a in late stage serous carcinoma was associated significantly with poor progression-free survival (P = 0.0058). CONCLUSIONS: A significant correlation was detected between the deregulation of specific types of miRNAs, such as miR-519a, miR-153 and miR-485-5p, and clinical variables as well as histological subtypes in ovarian cancers. Hence, these miRNAs may perform functions as diagnostic or prognostic biomarkers.

Novel multifunctional 18F-labelled PET tracer with prostate-specific membrane antigen-targeting and hypoxia-sensitive moieties.

Prostate cancer is one of the most frequently found cancers in men worldwide. Prostate-specific membrane antigen (PSMA) is typically highly expressed in prostate cancer, and the Glu-Urea-Lys (GUL) structure has recently received considerable attention as a key unit of PSMA-targeting agents. Additionally, one of the common characteristics of many solid tumors, such as prostate cancer, is hypoxia. In this study, novel multifunctional PSMA inhibitors containing a PSMA-targeting moiety either with or without a hypoxia-sensitive moiety (18F-PEG3-ADIBOT-2NI-GUL and 18F-PEG3-ADIBOT-GUL, respectively; ADIBOT: azadibenzocyclooctatriazole, 2NI: 2-nitroimidazole) were designed and synthesized, and their feasibility as PET tracers for prostate cancer imaging studies was examined. The compounds labelled with 18F via the copper-free click reaction were stable in human serum and showed nanomolar binding affinities in in vitro PSMA binding assays. Micro-PET and biodistribution studies indicate that both 18F-labelled inhibitors successfully accumulated in prostate cancer regions, and 18F-PEG3-ADIBOT-2NI-GUL showed a 2-fold higher tumor-to-total non-target organ ratio than that of 18F-PEG3-ADIBOT-GUL, suggesting that the synergistic effects of the PSMA-targeting GUL moiety and the hypoxia-sensitive 2-nitroimidazole moiety can increase tumor uptake of the novel PET tracers in prostate cancer. These findings suggest that this novel multifunctional PET tracer with an 18F-labelled PSMA inhibitor and a 2-nitroimidazole moiety is a potent candidate to provide better diagnosis of prostate cancer via PET imaging studies.

Synthesis of 18F-Labeled Aryl Fluorosulfates via Nucleophilic Radiofluorination.

Sulfuryl fluoride gas is a key reagent for SO2F transfer. However, conventional SO2F transfer reactions have limited 18F-radiochemistry translation, due to the inaccessibility of gaseous [18F]SO2F2. Herein, we report the first SO2F2-free synthesis of aryl [18F]fluorosulfates from both phenolic and isolated aryl imidazylate precursors with cyclotron-produced 18F-. The radiochemical yields ranged from moderate to good with excellent functional group tolerance. The reliability of our approach was validated by the automated radiosynthesis of 4-acetamidophenyl [18F]fluorosulfate.

Catalyst-Free Aromatic Radiofluorination via Oxidized Iodoarene Precursors.

Oxidized iodoarenes (OIAs), prepared via mCPBA-mediated oxidation, have been demonstrated as versatile precursors for the synthesis of [18F]fluoroarenes in the absence of catalysts. OIAs have been identified as intermediates in single-pot syntheses of iodonium salts and ylides but have never been recognized as radiofluorination precursors. Here, the isolated OIAs were used without any catalysts to produce functionalized [18F]fluoroarenes, regardless of the electronic nature of the arenes. This method was also applied to the production of radiolabeling synthons for use as aromatic 18F-labeled building blocks.

Novel potential pyrazolopyrimidine based translocator protein ligands for the evaluation of neuroinflammation with PET.

Translocator protein (TSPO) is an interesting biological target because TSPO overexpression is associated with microglial activation caused by neuronal damage or neuroinflammation, and these activated microglia are involved in several central nervous system diseases. Herein, novel fluorinated ligands (14a-c and 16a-c) based on a 2-phenylpyrazolo[1,5-a]pyrimidin-3-yl acetamide scaffold were synthesized, and in vitro characterization of each of the novel ligands was performed to elucidate structure activity relationships. All of the newly synthesized ligands displayed nano-molar affinity for TSPO. Particularly, an in vitro affinity study suggests that 2-(5,7-diethyl-2-(4-(3-fluoro-2-methylpropoxy)phenyl)pyrazolo[1,5-a]pyrimidin-3-yl)-N,N-diethylacetamide (14a), which exhibited high nano-molar affinity for TSPO and proper lipophilicity, was suitable for in vivo brain studies. Thus, radiosynthesis from tosylate precursor 13a using fluorine-18 was performed, and [18F]14a was obtained in a 31% radiochemical yield (decay-corrected). Dynamic positron emission tomography (PET) imaging studies were performed in a lipopolysaccharide (LPS)-induced neuroinflammation rat model using [18F]14a to identify the location of inflammation in the brain with a high target-to-background signal ratio. In addition, we validated that the locations of inflammatory lesions found by PET imaging were consistent with the locations observed by histological examination of dissected brains using antibodies. These results suggest that [18F]14a is a novel promising PET imaging agent for diagnosing neuroinflammation, and it may also prove to be applicable for diagnosing other diseases, including cancers associated with altered TSPO expression, using PET techniques.

Korean Guidelines for the Pharmacological Treatment of Social Anxiety Disorder: Initial Treatment Strategies.

OBJECTIVE: The aim of the present study was to provide clinical consensus and evidence regarding initial treatment strategies for the pharmacological treatment of social anxiety disorder (SAD) in Korea. METHODS: We prepared a questionnaire to derive a consensus from clinicians regarding their preference for the pharmacological treatment of SAD in Korea. Data regarding medication regimens and psychotropic drugs used during initial treatment, the doses used, and the pharmacological treatment duration were obtained. Responses were obtained from 66 SAD experts, and their opinions were classified into three categories (first-line, second-line, third-line) using a chi-square analysis. RESULTS: Clinicians agreed upon first-line regimens for SAD involving monotherapy with selective serotonin reuptake inhibitors (SSRIs) or the serotonin-norepinephrine reuptake inhibitor (SNRI) venlafaxine, or combined therapy using antidepressants with betablockers or benzodiazepines on a standing or as-needed basis. First-line psychotropic drug choices for initial treatment included the following: escitalopram, paroxetine, sertraline, venlafaxine, and propranolol. The medication dosage used by domestic clinicians was found to be comparable with foreign guidelines. Domestic clinicians tended to make treatment decisions in a shorter amount of time and preferred a similar duration of maintenance treatment for SAD when compared with foreign clinicians. CONCLUSION: This study may provide significant information for developing SAD pharmacotherapy guidelines in Korea, especially in the early stage of treatment.

MicroRNAs overexpressed in ovarian ALDH1-positive cells are associated with chemoresistance.

BACKGROUND: Ovarian carcinoma is the leading cause of cancer death worldwide among gynecological malignancies, and the majority of cases are related with recurrence and chemoresistance. Cancer stem cells (CSCs) are believed to be one of the causes of recurrent or chemoresistant ovarian cancer, and microRNAs are regulatory molecules newly implicated to control a variety of cellular processes, including CSCs. Therefore, we identified ovarian CSC-specific microRNAs and investigated their clinicopathological implication in ovarian carcinomas. METHODS: We isolated ALDH1 (+) cell population using the Aldefluor assay, and examined the differential expression pattern of miRNAs between ALDH1 (+) and ALDH1 (-) cells using a high-throughput microRNA microarray. We further investigated the expression patterns of differentially expressed miRNAs in human ovarian cancer samples using the real-time reverse transcription-polymerase chain reaction and analyzed their clinical impact in patients with ovarian cancer. RESULTS: We found that high ALDH1 expression was associated with chemoresistance in in vitro and ex vivo samples (p = 0.024). We identified six miRNAs, including miR-23b, miR-27a, miR-27b, miR-346, miR-424, and miR-503, overexpressed in ALDH1 (+) cells, and they were significantly upregulated in chemoresistant ovarian cancer cells (1.4 ~ 3.5-fold) and tumor samples (2.8 ~ 5.5-fold) compared with chemosensitive group. Upregulation of ALDH1 (p = 0.019) and miR-503 (p = 0.033) correlated with high clinical stage, and upregulation of miR-27a was related with distant metastasis (p = 0.046) in patients with ovarian cancer. CONCLUSION: Our findings indicate that ALDH1 is a useful marker for enriching ovarian CSCs, and high expression of ALDH1 and its related miRNAs, particularly miR-23b, miR-27b, miR-424, and miR-503, are significantly implicated in chemoresistance and tumor progression in ovarian cancer.

Potential side effects of dendritic cells pulsed with allogenic melanoma cell lysate in mice.

An attempt has been made to investigate the toxicity of cancer immunotherapy based on the dendritic cells pulsed with lysate of allogenic melanoma cell, DM401. Dendritic cells pulsed with lysate of clone M3 were subcutaneously administered once a week eight times to C57BL/6 mice at 0, 2.5, 5, and 10 x 10(7) cells/kg. No changes attributable to the administration were observed in clinical signs and food and water consumption. The administration induced slight increases in body weights, white blood cells, total protein, total cholesterol, triglyceride, phospholipids, and absolute spleen weights, but a slight decrease in albumin/globulin ratio. Microscopic examinations revealed the infiltration of inflammatory cells in the lung, mainly in the pulmonary arteriole, in which the tunica media thickened, and in the pulmonary alveoli and alveolar space. Thickened tunica media of pulmonary arteriole was observed in both males and females at all selected doses. In addition, the subcutis at the test substance-application site showed inflammation and fibrosis. In conclusion, lung is a target organ of DM401, and most of the changes including the findings in lung are considered as the immunomodulatory functions of dendritic cells.