A Functional Screening Identifies a New Organic Selenium Compound Targeting Cancer Stem Cells: Role of c-Myc Transcription Activity Inhibition in Liver Cancer.

Cancer stem cells (CSCs) are reported to play essential roles in chemoresistance and metastasis. Pathways regulating CSC self-renewal and proliferation, such as Hedgehog, Notch, Wnt/ß-catenin, TGF-ß, and Myc, may be potential therapeutic targets. Here, a functional screening from the focused library with 365 compounds is performed by a step-by-step strategy. Among these candidate molecules, phenyl-2-pyrimidinyl ketone 4-allyl-3-amino selenourea (CU27) is chosen for further identification because it proves to be the most effective compound over others on CSC inhibition. Through ingenuity pathway analysis, it is shown CU27 may inhibit CSC through a well-known stemness-related transcription factor c-Myc. Gene set enrichment analysis, dual-luciferase reporter assays, expression levels of typical c-Myc targets, molecular docking, surface plasmon resonance, immunoprecipitation, and chromatin immunoprecipitation are conducted. These results together suggest CU27 binds c-Myc bHLH/LZ domains, inhibits c-Myc-Max complex formation, and prevents its occupancy on target gene promoters. In mouse models, CU27 significantly sensitizes sorafenib-resistant tumor to sorafenib, reduces the primary tumor size, and inhibits CSC generation, showing a dramatic anti-metastasis potential. Taken together, CU27 exerts inhibitory effects on CSC and CSC-associated traits in hepatocellular carcinoma (HCC) via c-Myc transcription activity inhibition. CU27 may be a promising therapeutic to treat sorafenib-resistant HCC.

Asymmetric Synthesis and Absolute Configuration Assignment of a New Type of Bedaquiline Analogue.

Bedaquiline is the first FDA-approved new chemical entity to fight multidrug-resistant tuberculosis in the last forty years. Our group replaced the quinoline ring with a naphthalene ring, leading to a new type of triarylbutanol skeleton. An asymmetric synthetic route was established for our bedaquiline analogues, and the goal of assigning their absolute configurations was achieved by comparison of experimental and calculated electronic circular dichroism spectra, and was confirmed by the combined use of circular dichroism and NMR spectroscopy.

Synthesis and biological evaluation of substituted 4-(thiophen-2-ylmethyl)-2H-phthalazin-1-ones as potent PARP-1 inhibitors.

We have developed a series of substituted 4-(thiophen-2-ylmethyl)-2H-phthalazin-1-ones as potent PARP-1 inhibitors. Preliminary biological evaluation indicated that most compounds possessed inhibitory potencies comparable to, or higher than AZD-2281. Among these compounds, 18q appeared to be the most notable one, which displayed an 8-fold improvement in enzymatic activity compared to AZD-2281. These efforts lay the foundation for our further investigation.

An efficient synthesis of enantiopure (R)-heteroarylpyrimidine analogs.

An efficient synthesis of enantiopure (R)-heteroarylpyrimidine analogs is described here, which involves introduction of a chiral group, formation and separation of diasteroisomers and final transformation of an amide to an ester. The absolute configuration of the enantiopure HAPs is confirmed by X-ray analysis of their intermediates.

[The observation of the effects of a micromolecular compound J2 on rat corneal allograft using atomic force microscopy].

OBJECTIVE: To study the cell membrane of corneal endothelium with a micromolecular compound J2 in corneal allograft of rat using atomic force microscopy (AFM). METHODS: Cohort study. Subjects were divided into two groups: group A (n = 15): experimental group; group B (n = 15): placebo control group. At the fifth, tenth, fifteen, twentieth, twenty-fifth day after penetrating keratoplasty, the donor implant was separated from receipt bed, one part of which was stained by HE and the others fixed into AFM sample. Amplitude and height images were obtained in the tapping mode with a scan rate of 2 Hz and an integral gain of 0.3 to 0.5. Statistical analysis was performed using single-factor analysis of variance and P value was calculated. RESULTS: The average transplant survival time in group A was (33.12 ± 6.80) d, and those in group B was (18.87 ± 4.19) d. There were significant difference between two group (F = 47.7449, P = 0.00). There were obvious differences on ultrastructure measured by AFM between two groups. At the fifth day after penetrating keratoplasty, regular hexagonal structure of corneal endothelium was observed by AFM in both two group. The diameter of corneal endothelium was about 15 µm, uneven microstructure of cell could be found. The time being, different changes were arose in two group: a clear microstructure could be found in group A, however the microstructure of cell could not be recognized in group B. One way analysis of variance showed that significant differences on parameters (Ra, Rp and Rv) were found between two groups (P < 0.05). At the fifth day after penetrating keratoplasty, group A: Ra (97.64 ± 31.58) nm, Rp (297.79 ± 25.19) nm, Rv (545.55 ± 25.83) nm; group B: Ra (112.61 ± 34.29) nm, Rp (265.06 ± 24.17) nm, Rv (544.41 ± 21.78) nm (Fa = 30.9416, P = 0.0000; Fp = 263.6018, P = 0.0000; Pv = 1.2013, P = 0.2735). At the tenth day after penetrating keratoplasty, group A: Ra (102.98 ± 32.98) nm, Rp (711.38 ± 21.94) nm, Rv (639.89 ± 22.58) nm; group B: Ra (222.85 ± 31.28) nm, Rp (111.22 ± 20.35) nm, Rv (746.49 ± 23.17) nm (Fa = 2086.4535, P = 0.0000; Fp = 53768.4676, P = 0.0000; Pv = 3257.3178, P = 0.0000). At the fifteenth day after penetrating keratoplasty, group A: Ra (87.44 ± 34.97) nm, Rp (344.18 ± 21.09) nm, Rv (482.61 ± 22.27) nm; group B: Ra (197.64 ± 35.72) nm, Rp (510.76 ± 24.98) nm, Rv (545.62 ± 23.17) nm (Fa = 1458.1057, P = 0.0000; Fp = 7788.6963, P = 0.0000; Pv = 1153.2860, P = 0.0000). At the twentieth day after penetrating keratoplasty, group A: Ra (85.85 ± 32.53) nm, Rp (348.69 ± 21.26) nm, Rv (367.65 ± 23.12) nm; group B: Ra (201.36 ± 34.12) nm, Rp (788.58 ± 20.34) nm, Rv (563.33 ± 21.01) nm (Fa = 1801.1215, P = 0.0000; Fp = 67 057.9516, P = 0.0000; Fv = 11 770.2195, P = 0.0000). At the twenty-fifth day after penetrating keratoplasty, group A: Ra (104.97 ± 32.47) nm, Rp (395.05 ± 20.38) nm, Rv (396.17 ± 21.59) nm; group B: Ra (43.85 ± 31.28) nm, Rp (249.88 ± 20.79) nm, Rv (154.88 ± 22.37) nm (Fa = 551.4134, P = 0.0000; Fp = 7458.9255, P = 0.0000; Pv = 18 070.5189, P = 0.0000). CONCLUSIONS: The morphology and ultrastructure of corneal endothelium in group A with J2 were different from group B by observation with AFM. J2 was an effect micromolecular in prevention of corneal allograft rejection.

[On-line coupling of microcolumn electrophoresis and UV-Vis spectrophotometry].

In the present paper, a laboratory-made high-performance electrophoresis microcolumn unit was prepared for UV-Vis spectrophotometer. X-ray diffraction was used in the preparation of electrophoretic microcolumns. And an analytical technique of microcolumn electrophoresis coupled with UV-Vis spectrophotometry was introduced. Uniform quartz microncrystals were prepared by hydrothermal synthesis. Their crystalline phase and morphology were identified by X-ray diffraction and scanning electron microscope, respectively. The quartz microncrystals were packed into a 2-mm i. d. fused-silica tube to prepare the electrophoretic microcolumn. With 1.5 mmol x L(-1) disodium phosphate buffer solution (pH 11.5) containing 25% (phi) methanol and 10% (phi) acetonitrile, tryptophan, phenylalanine and tyrosine were on-line separated on line and detected by microcolumn electrophoresis coupled with UV-Vis spectrophotometry without derivatization. The limits of detection were 0.037, 0.20 and 0.20 micromol x L(-1), respectively. The separation efficiency of tryptophan was 4.5 x 10(4) plates/m. The sample capacity of the electrophoretic microcolumn achieved 35 microL. It was found that the electrophoretic microcolumn packed with quartz microncrystals was able to limit Joule heat, increase sample capacity and enhance detection sensitivity. The laboratory-made electrophoretic microcolumn could be a high-performance separation unit for conventional UV-Vis spectrophotometer. The on-line coupling of microcolumn electrophoresis and UV-Vis spectrophotometry could separate and determine samples with complicated matrices, reduce zone broadening and enhance separation efficiency, so expand the analytical function of spectrophotometer in the trace analysis of mixed components with overlapped spectra.

Electrophoretic separation with 2-mm inner diameter fused-silica microcolumn packed with quartz microncrystals and its application.

The feasibility of a microcolumn electrophoresis technique was investigated with a 100mm length, 2mm I.D. fused-silica microcolumn packed with uniform quartz microncrystals prepared by hydrothermal synthesis. To evaluate the separation technique, tryptophan, phenylalanine and tyrosine were primarily separated by the microcolumn electrophoresis and detected at 216 nm without derivatization by an ordinary spectrophotometer. The separation conditions of the amino acids were optimized. With 1.5 mmol/L disodium phosphate buffer solution (pH 11.5) containing 25% (v/v) methanol and 10% (v/v) acetonitrile, the three amino acids were separated and the separation efficiency of tryptophan was 4.5x10(4)plates/m. The limits of detection were 0.035, 0.22 and 0.20 micromol/L, respectively. The sample capacity of the electrophoretic microcolumn achieved 35 microL. The proposed method was used to determine these amino acids in compound amino acid injection samples without derivatization. For the simplicity and portability of the microcolumn electrophoresis, it is studied as one of the high-performance separation techniques for an in situ and real-time electrokinetic flow analysis system. For its high detection sensitivity and large sample capacity, it can be developed for preparative electrophoresis.

Determination of polyphenol components in herbal medicines by micellar electrokinetic capillary chromatography with Tween 20.

A simple and convenient method of micellar electrokinetic capillary chromatography (MEKC) using polyoxyethylene sorbitan monolaurate (Tween 20) to form single micelle and methanol as a buffer additive was introduced for the simultaneous determination of five polyphenols, including scopoletin, rutin, esculetin, chlorogenic acid and caffeic acid. A running buffer solution of pH 9.3, 20 mmol/L sodium tetraborate containing 64 mmol/L Tween 20 and 9% (v/v) methanol was adopted in the separation. Because rutin and esculetin were difficult to be separated by capillary zone electrophoresis (CZE) and SDS-based MEKC, Tween 20-based MEKC was adopted and the polyphenols were separated satisfactorily. The proposed method was used to determine the polyphenol components in the herbal medicine of Cortex fraxini. The separation mechanism of Tween 20-based MEKC for the polyphenols was discussed preliminarily.

Determination of amino acids in tobacco samples by capillary electrophoresis/indirect absorbance detection with isolation of the electrolysis compartment and p-Aminobenzoic acid as a background electrolyte.

A fast, convenient and sensitive method of capillary zone electrophoresis (CZE) and indirect UV detection was proposed for the determination of 16 amino acids. p-Aminobenzoic acid (PAB) was selected as a background electrolyte (BGE). An isolated cell included a BGE buffer part and an electrode buffer one, which were jointed with a glass frit. The isolated cell can prevent PAB from the electrode reaction and improve the stability of the detection baseline. The separation conditions of amino acids were investigated, such as different BGEs, BGE concentration, buffer pH and electroosmotic flow (EOF) modifiers. Under the selected separation conditions, 14 amino acid peaks could be separated in 12 min. The detection limits of the amino acids were in the range of 1.7 - 4.5 micromol/L. The isolated cell is suitable for reagents reacting on the electrodes in capillary electrophoresis. The proposed method has been successfully applied to the determination of the amino acids in tobacco samples.

Study on pressurizing electroosmosis pump for chromatographic separation.

A porous core electroosmosis pump was studied and improved in accordance with the electroosmosis theory. Hexamethylene tetraamine (HMTA) was used as the additive of pump carrier solution to improve the flow rate stability and delivery efficiency. The influences of the electric field strength, porous core dimension and acetonitrile concentration of carrier solution on the pump flow rate and output pressure were investigated in detail. The improved electroosmosis pump can provide not only steady flow rate and large flow range, but also moderate output pressure. With the pump carrier solution of 0.5mmol/L HMTA and the working voltage of 4950V, the pump output pressure, flow rate and delivery efficiency achieved 1.1MPa, 1.3mL/min and 3.2mL/(minmA), respectively. The pump can be employed for mobile phase delivery in the reversed-phase chromatographic separation of monolithic silica columns.

Reversed-phase electrochromatography with a monolithic microcolumn prepared in a 2.2-mm-inner diameter fused-silica tube.

Capillary electrochromatography possesses advantages of high separation efficiency and velocity, but it also has its disadvantages due to its small inner diameter, such as poor detection sensitivity, low sample capacity, and some trouble in its column preparation. To overcome these shortcomings, a monolithic microcolumn with a surface area larger than 200 m2/g was prepared by sol-gel polycondensation of tetraethoxysilane-hydrochloric acid-poly(ethylene glycol) and filling with fine quartz sand in a 2.2-mm-i.d. fused-silica tube. The prepared microcolumn was used in the separation of aromatic compounds by reversed-phase electrochromatography. Some factors that affected electroosmotic flow were explored, such as electric field strength, buffer concentration, and buffer pH. Acetonitrile concentration in the mobile phase was investigated for phenol, benzene, and naphthalene separation. The separation results were satisfying with the electrochromatographic microcolumns. The detection limits of phenol, benzene, and naphthalene were 0.07, 0.26, and 0.04 mg/L, respectively.

Effects of a fatty acid synthase inhibitor on adipocyte differentiation of mouse 3T3-L1 cells.

AIM: To investigate the influence of C75, a fatty acid synthase inhibitor, on adipocyte differentiation. METHODS: Mouse 3T3-L1 preadipocytes were induced to differentiation by insulin, isobutylmethylxanthine, and dexamethasone. Oil red O staining was performed and activity of glycerol-3-phosphate dehydrogenase (GPDH) was measured. The level of peroxisome proliferators-activated receptor gamma (PPARgamma) mRNA was assayed by semi-quantitative reverse transcription PCR. RESULTS: C75 blocked the adipogenic conversion in a dose-dependent manner and the inhibitory effects occurred both in the early phases (48 h) and in the latter phases (8 d) of the process. Treatment with C75 for 8 d induced more decrease in lipid content than 48 h (P<0.01). Treatment with C75 50 mg/L for 48 h or 8 d decreased GPDH activity by 52.8 % and 31.2 % of Vehicle, respectively. Treatment with C75 10-50 mg/L for 48 h or 8 d down-regulated PPARgamma mRNA expression compared with control (P<0.01). CONCLUSION: C75 blocked the adipocyte differentiation, which was related with down-regulation of PPARgamma mRNA.