Wen-Xue Chen

Study on metabonomic characteristics of human lung cancer using high resolution magic-angle spinning 1H NMR spectroscopy and multivariate data analysis

Lung cancer causes serious health problems. Clinical diagnosis of lung cancer relies on histopathological evalution of tissue specimen. However, extensive knowledge of the metabolic biochemistry of tumors can potentially provide important information for accurate diagnosis of lung cancer. High resolution magic‐angle spinning NMR spectroscopy has emerged and be widely acknowledged as an excellent tool in investigating tissue metabolism. Moreover, the combination of high resolution magic‐angle spinning NMR technique and multivariate data analysis has become an important metabonomics platform for studying the intact biological tissues. This study reported the metabonomic characteristics of 51 lung tissues from 17 patients with lung cancer using the high resolution magic‐angle spinning 1H NMR spectroscopy and the multivariate data analysis methods including principal component analysis and orthogonal partial least squares‐discriminant analysis. Clear differences among the metabonomic characteristics of lung cancer tissues at various sites were disclosed. Compared with the adjacent noninvolved tissues, the lung cancer tissues had significantly high levels of aspartate, phosphocholine, glycerophosphocholine and lactate but significantly low levels of glucose and valine. Furthermore, significantly positive (or negative) correlations were observed between the levels of some metabolites such as lactate, fatty acids, valine, phosphocholine, and glycerophosphocholine. Magn Reson Med, 2011.

Asymmetric Synthesis of the HMG-CoA Reductase Inhibitor Atorvastatin Calcium: An Organocatalytic Anhydride Desymmetrization and Cyanide-Free Side Chain Elongation Approach

An efficient asymmetric synthesis of atorvastatin calcium has been achieved from commercially available diethyl 3-hydroxyglutarate through a novel approach that involves an organocatalytic enantioselective cyclic anhydride desymmetrization to establish C(3) stereogenicity and cyanide-free assembly of C7 amino type side chain via C5+C2 strategy as the key transformations.

Pyrimidine sulfonylacetanilides with improved potency against key mutant viruses of HIV-1 by specific targeting of a highly conserved residue

Based on molecular simulation, the etravirine-VRX-480773 hybrids previously disclosed by our group were optimized to yield novel pyrimidine sulfonylacetanilides 8 with improved activity against a panel of seven clinically relevant single and double mutant strains of HIV-1. The improvement in potency in this in vitro model of HIV RNA replication partly validates the mechanism by which this class of allosteric pyrimidine derivatives inhibits the reverse transcriptase (RT), and represents a remarkable step forward in the development of anti-HIV drugs.

Grade classification of neuroepithelial tumors using high-resolution magic-angle spinning proton nuclear magnetic resonance spectroscopy and pattern recognition

Clinical data have shown that survival rates vary considerably among brain tumor patients, according to the type and grade of the tumor. Metabolite profiles of intact tumor tissues measured with high-resolution magic-angle spinning proton nuclear magnetic resonance spectroscopy (HRMAS 1H NMRS) can provide important information on tumor biology and metabolism. These metabolic fingerprints can then be used for tumor classification and grading, with great potential value for tumor diagnosis. We studied the metabolic characteristics of 30 neuroepithelial tumor biopsies, including two astrocytomas (grade I), 12 astrocytomas (grade II), eight anaplastic astrocytomas (grade III), three glioblastomas (grade IV) and five medulloblastomas (grade IV) from 30 patients using HRMAS 1H NMRS. The results were correlated with pathological features using multivariate data analysis, including principal component analysis (PCA). There were significant differences in the levels of N-acetyl-aspartate (NAA), creatine, myo-inositol, glycine and lactate between tumors of different grades (P<0.05). There were also significant differences in the ratios of NAA/creatine, lactate/creatine, myo-inositol/creatine, glycine/creatine, scyllo-inositol/creatine and alanine/creatine (P<0.05). A soft independent modeling of class analogy model produced a predictive accuracy of 87% for high-grade (grade III–IV) brain tumors with a sensitivity of 87% and a specificity of 93%. HRMAS 1H NMR spectroscopy in conjunction with pattern recognition thus provides a potentially useful tool for the rapid and accurate classification of human brain tumor grades.

Development of Bifunctional Thiourea Organocatalysts Derived from a Chloramphenicol Base Scaffold and their Use in the Enantioselective Alcoholysis of meso Cyclic Anhydrides

The synthesis of new chloramphenicol‐base‐derived thiourea organocatalysts, (1S,2R)‐12 a–f and (1R,2R)‐15 a–c, and their use in the enantioselective alcoholysis of meso‐anhydrides are described. In particular, hemiesters afforded excellent enantioselectivities if low loadings of (1S,2R)‐12 a–f were used. Almost no enantioselectivities were achieved with the use of (1R,2R)‐15 a–c. This technique was used to synthesize (R)‐(−)‐baclofen.

Metabonomic characteristics and biomarker research of human lung cancer tissues by HR1H NMR spectroscopy

BACKGROUND The combination of NMR spectroscopy and multivariate data analysis (MVDA), such as orthogonal partial least squares-discriminant analysis (OPLS-DA), has been collectively acknowledged as an excellent tool to investigate tissue metabolism and provide metabolite information for the diagnosis of disease, and become an important metabonomic platform for studies in biological tissues so far. METHODS Both ex vivo high resolution magic-angle spinning1H NMR and in vitro1H NMR spectroscopy technique were synchronously employed to analyze the metabonomic characteristics of 102 lung tissues from 34 patients with lung cancer in hope to identify potential diagnostic biomarkers for malignancy detection in lung tissues. RESULTS Significant elevations in the levels of lipids and lactate and significant reductions in the levels of myo-inositol and valine in the cancer tissues had been identified when compared with the adjacent non-involved tissues. Furthermore, the OPLSDA models calculated by two1H NMR spectra provided for relatively high sensitivity, specificity and good prediction accuracy in the identification of class membership regardless of the number of metabolites involved. CONCLUSIONS MVDA in combination with1H NMR spectra highlighted the potential of metabonomics in clinical settings so that the techniques might be further exploited for future lung cancer biomarker research or identification.

Synthesis and biological evaluation of CHX-DAPYs as HIV-1 non-nucleoside reverse transcriptase inhibitors

A series of new diarylpyrimidines (DAPYs) characterized by a halogen atom on the methylene linker between wing I and the central pyrimidine ring was synthesized and evaluated for their anti-HIV activity in MT-4 cell cultures. The two most promising compounds 7f and 7g showed excellent activity against wild-type HIV-1 with low nanomolar EC50 values of 0.005 and 0.009 μM, respectively, which were comparable to or more potent than all the reference drugs zidovudine (AZT), lamivudine (3TC), nevirapine (NEV), efavirenz (EFV), delaviridine (DLV) and etravirine (ETV). In particular, 7g also displayed strong activity against the double mutant strain 103N + 181C with an EC50 value of 8.2 μM. The preliminary structure-activity relationship (SAR) and molecular docking analysis of this new series of CHX-DAPYs were also investigated.

Synthesis and biological evaluation of DAPY-DPEs hybrids as non-nucleoside inhibitors of HIV-1 reverse transcriptase.

A series of new DAPY-DPEs hybrids, combined the important pharmacophores of DAPYs and DPEs, has been synthesized and biologically evaluated for their anti-HIV activities against wild-type HIV-1 strain IIIB, double RT mutant (K103N+Y181C) strain RES056 and HIV-2 strain ROD in MT-4 cell cultures. Many promising candidates with potent inhibitory activity (wild-type) within the EC50 range from 0.16 to 0.013 μM were obtained. In particular, 3c, 3p, 3r and 3s displayed low nM level EC50 values (35, 13, 50 and 17 nM, respectively) and high selectivity (9342, 25131, 2890 and 11338, respectively), which were much more potent than NVP (EC50=0.31 μM, SI=48), 3TC (EC50=2.24 μM, SI>39), DDI (EC50=23.20 μM, SI>9) and DLV (EC50=0.65 μM, SI>67), and comparable to AZT (EC50=0.0071 μM, SI>13144) and EFV (EC50=0.0062 μM, SI>1014). The HIV-1 reverse transcriptase inhibitory assay confirmed that these DAPY-DPEs hybrids targeted HIV-1 RT. Molecular simulation was performed to investigate the potential binding mode of the newly synthesized compounds. And reasonable explanation for the activity results was discussed with docking method.

Anti-HIV diarylpyrimidine–quinolone hybrids and their mode of action

A molecular hybridization approach is a powerful tool in the design of new molecules with improved affinity and efficacy. In this context, a series of diarylpyrimidine-quinolone hybrids were synthesized and evaluated against both wt HIV-1 and mutant viral strains. The most active hybrid 5a displayed an EC50 value of 0.28±0.07μM against HIV-1 IIIB. A couple of enzyme-based assays clearly pinpoint a RT-targeted mechanism of action. Docking studies revealed that these hybrids could be well located in the NNIBP of HIV-1 RT despite the bulky and polar properties of a quinolone 3-carboxylic acid moiety in the molecules.

A Novel and Practical Synthesis of 2-Amino-5-hydroxypropiophenone

In connection with our recent development of an efficient asymmetric total synthesis of irinotecan (CPT-11, 1), an analogue of the natural product camptothecin, approved by the FDA for treatment of refractory colorectal cancer,1,2 2-amino-5-hydroxypropiophenone (2) was required as a key intermediate for the construction of the AB ring with (4 ′ S)-tricyclic hydroxylactone 3, another known intermediate bearing CDE ring skeleton for the synthesis of CPT-11 through a Friedlander condensation strategy.3 Two precedents for the preparation of this intermediate 2 have been appeared in earlier works based on the