A novel synthetic small molecule YF-452 inhibits tumor growth through antiangiogenesis by suppressing VEGF receptor 2 signaling

Tumor angiogenesis is characterized by abnormal vessel morphology, endowing tumor with highly hypoxia and unresponsive toward treatment. To date, mounting angiogenic factors have been discovered as therapeutic targets in antiangiogenic drug development. Among them, vascular endothelial growth factor receptor 2 (VEGFR2) inhibitors exerts potent antiangiogenic activity in tumor therapy. Therefore, it may provide a valid strategy for cancer treatment through targeting the tumor angiogenesis via VEGFR2 pathway. In this study, we established a high-profile compounds library and certificated a novel compound named N-(N-pyrrolidylacetyl)-9-(4-bromobenzyl)-1,3,4,9-tetrahydro-β-carboline (YF-452), which remarkably inhibited the migration, invasion and tube-like structure formation of human umbilical vein endothelial cells (HUVECs) with little toxicity invitro. Rat thoracic aorta ring assay indicated that YF-452 significantly blocked the formation of microvascular exvivo. In addition, YF-452 inhibited angiogenesis in chick chorioallantoic membrane (CAM) and mouse corneal micropocket assays. Moreover, YF-452 remarkably suppressed tumor growth in xenografts mice model. Furthermore, investigation of molecular mechanism revealed that YF-452 inhibited VEGF-induced phosphorylation of VEGFR2 kinase and the downstream protein kinases including extracellular signal regulated kinase (ERK), focal adhesion kinase (FAK) and Src. These results indicate that YF-452 inhibits angiogenesis and may be a potential antiangiogenic drug candidate for cancer therapy.

Novel hemostatic agents based on gelatin-microbial transglutaminase mix

Hemostasis is a major challenge in surgical procedures and traumas. Conventional hemostatic methods have limited efficacy and may cause additional tissue damage. In this study, we designed a novel hemostatic agent based on the in situ gel formation of gelatin cross-linked by a novel microbial transglutaminase(mTGase), in which the amino acid sequences differed from commercial mTGases. The new hemostatic agent showed the same biochemical crosslinking chemistry as the final stages of the blood coagulation cascade while using gelatin as a "structural" protein(rather than fibrin) and a calcium-independent mTGase as the crosslinking catalyst(rather than factor XIIIa). In rat liver hemostasis models, the hemostatic agent not only showed a similar hemostatic effect as that of SURGIFLO~(positive control), but also stronger adhesion strength and elasticity than SURGIFLO~.Therefore, this biomimetic gelatin-mTGase mix hemostatic is a novel and effective surgical sealant.

Structural insights reveal the specific recognition of meiRNA by the Mei2 protein

In the fission yeast Schizosaccharomyces pombe,Mei2,an RNA-binding protein essential for entry into meiosis,regulates meiosis initiation.Mei2 binds to a specific non-coding RNA species,meiRNA,and accumulates at the sme2 gene locus,which encodes meiRNA.Previous research has shown that the Mei2 C-terminal RNA recognition motif(RRM3)physically interacts with the meiRNA 5'region in vitro and stimulates meiosis in vivo.However,the underlying mechanisms still remain elusive.We first employed an in vitro crosslinking and immunoprecipitation sequencing(CLIP-seq)assay and demonstrated a preference for U-rich motifs of meiRNA by Mei2 RRM3.We then solved the crystal structures of Mei2 RRM3 in the apo form and complex with an 8 mer RNA fragment,derived from meiRNA,as detected by in vitro CLIP-seq.These results provide structural insights into the Mei2 RRM3-meiRNA complex and reveal that Mei2 RRM3 binds specifically to the Uuc(U)sequence.Furthermore,a structure-based Mei2 mutation,Mei2F644A causes defective karyogamy,suggesting an essential role of the RNA-binding ability of Mei2 in regulating meiosis.