A New Analogue of Echinomycin and a New Cyclic Dipeptide from a Marine-Derived Streptomyces sp. LS298.

Quinomycin G (1), a new analogue of echinomycin, together with a new cyclic dipeptide, cyclo-(l-Pro-4-OH-l-Leu) (2), as well as three known antibiotic compounds tirandamycin A (3), tirandamycin B (4) and staurosporine (5), were isolated from Streptomyces sp. LS298 obtained from a marine sponge Gelliodes carnosa. The planar and absolute configurations of compounds 1 and 2 were established by MS, NMR spectral data analysis and Marfey's method. Furthermore, the differences in NMR data of keto-enol tautomers in tirandamycins were discussed for the first time. Antibacterial and anti-tumor activities of compound 1 were measured against 15 drug-sensitive/resistant strains and 12 tumor cell lines. Compound 1 exhibited moderate antibacterial activities against Staphylococcuse pidermidis, S. aureus, Enterococcus faecium, and E. faecalis with the minimum inhibitory concentration (MIC) values ranged from 16 to 64 µg/mL. Moreover, it displayed remarkable anti-tumor activities; the highest activity was observed against the Jurkat cell line (human T-cell leukemia) with an IC50 value of 0.414 µM.

[The anti-tumor activity and molecular mechanisms of an Aurora kinase inhibitor ZLJ213 in suppressing colon cancer growth].

The aim of this study is to evaluate anti-tumor activities and mechanism of a novel kinase inhibitor ZLJ213 which targeted Aurora A and vascular endothelial growth factor receptor (VEGFR) in vitro and in vivo against human colon cancer. Results showed that ZLJ213 inhibited cell proliferation and induced cell cycle arrest and apoptosis of HCT1 16 and SW48 cell lines. In HCT116-derived xenograft, ZLJ213 dosed at 100 mg · kg(-1) inhibited tumor growth by 73.24%. The IC50 of ZLJ213 on the expression of p-Aurora A was 0.258 µmol · L(-1) analyzed by ELISA. Under the concentration of 0.08 µmol · L(-1), ZLJ213 could inhibit the activities of Aurora A, Histone H3 and VEGFR of HCT116 and SW48 cell lines. Simultaneously, ZLJ213 induced activation of Caspase 3 and PARP cleavage. Above data suggested that ZLJ213 had the ability to inhibit cell proliferation and induce cell apoptosis both in vitro and in vivo in colon cancer, and down-regulate the expression of p-Aurora A and p-VEGFR. ZLJ213 might be a potential therapeutic agent against colon cancer.

[Development of a novel screening assay for inhibitors targeting HIF-1alpha and P300 interaction].

Hypoxia is a general characteristic of most solid malignancies and intimately related to cancer progression. Homeostatic response to hypoxia is primarily mediated by hypoxia inducible factor-1alpha (HIF-1alpha) that elicits transcriptional activity through recruitment P300 coactivator. Targeting the interaction of HIF- alpha and P300 would thus constitute a novel approach for cancer treatment by suppressing tumor angiogenesis and metastasis. Here, a screening assay was developed for inhibitors targeting the interaction between HIF-1alpha and P300. The nucleotide sequence of human HIF-1alpha and P300 were cloned into pBIND and pACT vectors, named pBIND-HIF1alpha and pACT-P300. The interaction of HIF-1alpha and P300 was identified in HEK293 cell using mammalian two-hybrid system. And compound chetomin decreased their interaction in this mammalian two-hybrid system. We further verified HIF-1 inhibition effect of chetomin in U251-HRE cells. Therefore, we established a screening assay combined HIF-1alpha and P300 mammalian two-hybrid system and U251-HRE reporter assay for HIF-1 selective inhibitors.

[Anti-tumor activity and mechanism of T03 in vitro and in vivo].

The purpose of this study is to investigate the activity and mechanism of a new anti-tumor agent T03. MTT and colony formation assay were performed to determine anti-proliferation activity of T03 in vitro. Antitumor activity was observed by Renca xenograft model in vivo. The effect of T03 on cell cycle and apoptosis were measured by FCM analysis. Western blotting was performed to investigate the expression level of proteins in HepG2 cell lines treated with T03. T03 had anti-tumor activity by inhibiting tumor cell growth and colony formation in vitro, especially on hepatocellular carcinoma cells (HCC). At the concentration of 10 micromol x L(-1), T03 induced cell apoptosis and cell cycle arrest in HCC. Moreover, it proved that T03 reduced the tumor weight with the rate of 42.30% without any obviously side effect in Renca xenograft model. At the concentration of 2.0 micromol x L(-1), T03 was able to reduce the level of p-c-Raf (Ser259), and thus blocked Raf/MEK/ERK and AKT signaling in HepG2 cell lines. The result suggested that T03 has the potential to inhibit cell proliferation and induce cell apoptosis both in vitro and in vivo, particularly active against HCC, indicating T03 and its analogues may serve as a new anti-cancer drug against hepatocellular carcinoma.

[Design, synthesis and biological evaluation of fingolimod analogues containing diphenyl ether moiety].

A novel series of fingolimod analogues containing diphenyl ether moiety were designed and synthesized based on the modification of immunosuppressive agent fingolimod used in the treatment of multiple sclerosis. Compounds were evaluated in vivo for lymphopenic activity and heart rate affection. Most compounds showed moderate lymphopenic activity. It is worth noting that compounds 6c, 6d and 14c-14e showed considerable immunosuppressive activities comparable to fingolimod. And compound 14e had no effect on heart rate.

[Effect of a novel selective S1P1 agonist, Syl948, on mouse skin transplantation].

Syl948 is a synthesized selective S1P1 agonist with novel structure. HTRF-IP1 test indicated that Syl948-P, the active form of Syl948 in vitro, has strong activity against S1P1 (EC50: 83 +/- 16 nmol x L(-1)), but its effect on S1P3 was very weak (EC50: 1 026 +/- 90 nmol x L(-1)). In SD rats, oral administration of Syl948 10 mg x kg(-1) significantly decreased the peripheral blood lymphocytes (PBL), with the maximal PBL inhibition rate of 63%, which was as similar as equal dose of fingolimod (FTY720). Oral administration of Syl948 10 mg x kg(-1) had no effect on heart rate of SD rats, which was better than FTY720. Daily oral administration with Syl948 (2 or 4 mg x kg(-1)) significantly prolonged the survival time of the allografts of skin slice on mice. In summary, the above results demonstrated that Syl948 has great selectivity in vitro and good activity in vivo, which indicated its potential use as an anti-rejection drug in skin transplantation.

[Mechanism about therapeutic effect of meisoindigo on psoriasis via down-regulation of the TLR4-TAK-NF-kappaB pathways].

Meisoindigo is an indigo natural derivative commonly used in anti-cancer therapy. In the clinical application, it was also found to have good therapeutic effect on psoriasis. In order to further understand its mechanism of action, human normal keratinocyte cell line HaCaT and RAW 264.7 were used to identify if meisoindigo could affect the inflammatory factors such as NO and other important cytokines which were highly involved in psoriasis. Our results indicated that meisoindigo decreased the production of NO in LPS-stimulated RAW 264.7 cells and reduced the expression of cytokines in LPS-stimulated HaCaT cells. And TLR4-TAK-NF-kappaB was a possible pathway mainly involved in the attenuation of iNOS and pro-inflammatory cytokine production by meisoindigo, which may take part in the therapeutic effect of meisoindigo on psoriasis.

[Immunosuppressive effect of S1P1 receptor agonist FTY720].

FTY720 is a synthetic compound derived from the metabolites of Isaria sinclairii. Its unique chemical structure and mechanism appear to be distinctive from other known immunosuppressors. In the present study, the effect of FTY720 on immunosuppression and toxicity to heart was evaluated by detection of lymphocytes count, heart rate in rats, the survival time of the allografts of skin slice in mice and binding to S1P1 and S1P3 receptors by confocal. The results showed that FTY720 could induce lymphopenia, reduce the heart rates in rats and prolong the survival time of the allografts of skin slice in mice. The assay results on confocal showed that FTY720 can bind with S1P1 and S1P3 on surface of CHO-S1P1 and CHO-S1P3 cells. FTY720 could be developed for wide application for organ transplantation and self-immunity diseases.