Transcriptional factors smad1 and smad9 act redundantly to mediate zebrafish ventral specification downstream of smad5.

Bone morphogenetic proteins (BMPs) are multifunctional growth factors that play crucial roles during embryonic development and cell fate determination. Nuclear transduction of BMP signals requires the receptor type Smad proteins, Smad1, Smad5, and Smad9. However, how these Smad proteins cooperate in vivo to regulate various developmental processes is largely unknown. In zebrafish, it was widely believed that the maternally expressed smad5 is essential for dorso-ventral (DV) patterning, and the zygotically transcribed smad1 is not required for normal DV axis establishment. In the present study, we have identified zygotically expressed smad9, which cooperates with smad1 downstream of smad5, to mediate zebrafish early DV patterning in a functional redundant manner. Although knockdown of smad1 or smad9 alone does not lead to visible dorsalization, double knockdown strongly dorsalizes zebrafish embryos, which cannot be efficiently rescued by smad5 overexpression, whereas the dorsalization induced by smad5 knockdown can be fully rescued by overexpression of smad1 or smad9. We have further revealed that the transcription initiations of smad1 and smad9 are repressed by each other, that they are direct transcriptional targets of Smad5, and that smad9, like smad1, is required for myelopoiesis. In conclusion, our study uncovers that smad1 and smad9 act redundantly to each other downstream of smad5 to mediate ventral specification and to regulate embryonic myelopoiesis.

Synthesis and in vitro cytotoxic activity evaluation of novel heterocycle bridged carbothioamide type isosteviol derivatives as antitumor agents.

Two series of novel carbothioamide-substituted pyrazole and isoxazolidine derivatives were facilely prepared by functional interconversions in ring D of the tetracyclic diterpene isosteviol. The in vitro cytotoxic activities against four human tumor cell lines were evaluated. Our results indicated that carbothioamide-substituted pyrazole derivatives exhibited noteworthy cytotoxic activities. Specifically, compound 12p (IC(50)=6.51 µM) had the most potent cytotoxicity against Raji cell, which may be exploitable as a lead compound for the development of potent antitumor agents.

Ethyl ent-15α-[(2-meth-oxy-benz-yloxy)meth-yl]-16-oxobeyeran-20-oate.

The title compound, C(31)H(44)O(5), was synthesized from isostev-iol (systematic name: ent-16-ketobeyeran-19-oic acid). In the mol-ecule, the three six-membered rings adopt chair conformations and the stereochemistry of the A/B and B/C ring junctions are trans. The five-membered ring D adopts an envelope conformation with the methyl-ene C atom as the flap.

A systematic study of chiral homoprolinols and their derivatives in the catalysis of enantioselective addition of diethylzinc to aldehydes.

Homoprolinol analogs, a class of optically active γ-amino alcohols, were examined systematically in the enantioselective addition reactions of diethylzinc to aldehydes. By comparison of the results catalyzed by these γ-amino alcohols with those by the ß-amino alcohols based on pyrrolidine architecture reported in the literature references, we have observed that the γ-amino alcohols are superior to the corresponding ß-amino alcohols when the nitrogen and the oxygen are unsubstituted. Among the homoprolinols we tested, gave the best results (45-88% yields, 44-81% ee) in the addition reactions. To the best of our knowledge, has been noticed as one of the most efficient γ-amino alcohol catalysts based on pyrrolidine framework.

PSMB8 regulates glioma cell migration, proliferation, and apoptosis through modulating ERK1/2 and PI3K/AKT signaling pathways.

Glioma has been considered as one of the most aggressive and popular brain tumors of patients. It is essential to explore the mechanism of glioma. In this study, we established PSMB8 as a therapeutic target for glioma treatment. Expression of PSMB8 as well as Ki-67 was higher in glioma tissues demonstrated by western blot and immunohistochemistry. Then, the role of PSMB8 in migration and proliferation of glioma cells was investigated by conducting wound-healing, trans-well assay, cell counting kit (CCK)-8, flow cytometry assay and colony formation analysis. The data showed that interfering PSMB8 may inhibit the migration and proliferation of glioma cells by reducing expression of cyclin A, cyclin B1, cyclin D1, Vimentin, and N-cadherin, and by increasing expression of E-cadherin. Additionally, interfering PSMB8 may induce apoptosis of glioma cells by upregulating caspase-3 expression. Furthermore, these in vitro findings were validated in vivo and the ERK1/2 and PI3k/AKT signaling pathways were involved in PSMB8-triggered migration and proliferation of glioma cells. In an in vivo model, downregulation of PSMB8 suppressed tumor growth. In conclusion, PSMB8 is closely associated with migration, proliferation, and apoptosis of glioma cells, and might be considered as a novel prognostic indicator in patients with gliomas.

Tissue-specific derepression of TCF/LEF controls the activity of the Wnt/ß-catenin pathway.

Upon stimulation by Wnt ligands, the canonical Wnt/ß-catenin signalling pathway results in the stabilization of ß-catenin and its translocation into the nucleus to form transcriptionally active complexes with sequence-specific DNA-binding T-cell factor/lymphoid enhancer factor (TCF/LEF) family proteins. In the absence of nuclear ß-catenin, TCF proteins act as transcriptional repressors by binding to Groucho/Transducin-Like Enhancer of split (TLE) proteins that function as co-repressors by interacting with histone deacetylases whose activity leads to the generation of transcriptionally silent chromatin. Here we show that the transcription factor Ladybird homeobox 2 (Lbx2) positively controls the Wnt/ß-catenin signalling pathway in the posterior lateral and ventral mesoderm of the zebrafish embryo at the gastrula stage, by directly interfering with the binding of Groucho/TLE to TCF, thereby preventing formation of transcription repressor complexes. These findings reveal a novel level of regulation of the canonical Wnt/ß-catenin signalling pathway occurring in the nucleus and involving tissue-specific derepression of TCF by Lbx2.

Subtractive phage display technology identifies zebrafish marcksb that is required for gastrulation.

In the present study, we used a phage display technique to screen differentially expressed proteins from zebrafish post-gastrula embryos. With a subtractive screening approach, 6 types of single-chain Fv fragments (scFvs) were screened out from an scFv antibody phage display library by biopanning against zebrafish embryonic homogenate. Four scFv fragments (scFv1, scFv3, scFv4 and scFv6) showed significantly stronger binding to the tailbud embryos than to the 30%-epiboly embryos. A T7 phage display cDNA library was constructed from zebrafish tailbud embryos and used to identify the antigens potentially recognized by scFv1, which showed the highest frequency and strongest binding against the tailbud embryos. We acquired 4 candidate epitopes using scFv1 and the corresponding genes showed significantly higher expression levels at tailbud stage than at 30%-epiboly. The most potent epitope of scFv1 was the clone scFv1-2, which showed strong homology to zebrafish myristoylated alanine-rich C-kinase substrate b (Marcksb). Western blot analysis confirmed the high expression of marcksb in the post-gastrula embryos, and the endogenous expression of Marcksb was interfered by injection of scFv1. Zebrafish marcksb showed dynamic expression patterns during embryonic development. Knockdown of marcksb strongly affected gastrulation movements. Moreover, we revealed that zebrafish marcksb is required for cell membrane protrusion and F-actin alignment. Thus, our study uncovered 4 types of scFvs binding to zebrafish post-gastrula embryos, and the epitope of scFv1 was found to be required for normal gastrulation of zebrafish. To our knowledge, this was the first attempt to combine phage display technique with the embryonic and developmental study of vertebrates, and we were able to identify zebrafish marcksb that was required for gastrulation.

Design and stereoselective synthesis of novel isosteviol-fused pyrazolines and pyrazoles as potential anticancer agents.

Two series of novel isosteviol-fused pyrazoline and pyrazole derivatives were facilely synthesized via intramolecular 1,3-dipolar cycloaddition and condensation reaction, respectively. All compounds were characterized by NMR, IR and HRMS spectra. The stereochemistry of compounds 9b, 10, 11a and 11v were further confirmed by X-ray crystallographic analysis. The antiproliferative activities of the structurally related pyrazoline and pyrazole derivatives were tested in vitro on four human malignant cell lines (SGC 7901, A549, Raji and HeLa): Our results revealed that isosteviol-fused pyrazole derivatives exhibited noteworthy cytotoxic activities. Among them, 2,4-di-Cl-phenylpyrazole derivative 11t displayed better cytotoxities with IC50 values: 2.71, 3.18, 1.09 and 13.52 µM against SGC 7901, A549, Raji and HeLa, respectively, compared to cisplatin (IC50 values: 7.56, 17.78, 17.32 and 14.31 µM, respectively).