Aiphanol, a multi-targeting stilbenolignan, potently suppresses mouse lymphangiogenesis and lymphatic metastasis.

The high incidence of lymphatic metastasis is closely related to poor prognosis and mortality in cancers. Potent inhibitors to prevent pathological lymphangiogenesis and lymphatic spread are urgently needed. The VEGF-C-VEGFR3 pathway plays a vital role in driving lymphangiogenesis and lymph node metastasis. In addition, COX2 in tumor cells and tumor-associated macrophages (TAMs) facilitates lymphangiogenesis. We recently reported that aiphanol, a natural stilbenolignan, attenuates tumor angiogenesis by repressing VEGFR2 and COX2. In this study, we evaluated the antilymphangiogenic and antimetastatic potency of aiphanol using in vitro, ex vivo and in vivo systems. We first demonstrated that aiphanol directly bound to VEGFR3 and blocked its kinase activity with an half-maximal inhibitory concentration (IC50) value of 0.29 µM in an in vitro ADP-GloTM kinase assay. Furthermore, we showed that aiphanol (7.5-30 µM) dose-dependently counteracted VEGF-C-induced proliferation, migration and tubular formation of lymphatic endothelial cells (LECs), which was further verified in vivo. VEGFR3 knockdown markedly mitigated the inhibitory potency of aiphanol on lymphangiogenesis. In 4T1-luc breast tumor-bearing mice, oral administration of aiphanol (5 and 30 mg· kg-1 ·d-1) dose-dependently decreased lymphatic metastasis and prolonged survival time, which was associated with impaired lymphangiogenesis, angiogenesis and, interestingly, macrophage infiltration. In addition, we found that aiphanol decreased the COX2-dependent secretion of PGE2 and VEGF-C from tumor cells and macrophages. These results demonstrate that aiphanol is an appealing agent for preventing lymphangiogenesis and lymphatic dissemination by synergistically targeting VEGFR3 and inhibiting the COX2-PGE2-VEGF-C signaling axis.

Evaluation of a novel monoclonal antibody mAb109 by immuno-PET/fluorescent imaging for noninvasive lung adenocarcinoma diagnosis.

Monoclonal antibodies are believed to be magic bullets and hold great potential for lots of biological process. About 100 µg of mAb109 was expressed in 5 × 106 cells after 10 days' immunization. 64Cu-NOTA-mAb109 was synthesized with the specific activity of 0.74 MBq/µg and high in vitro stability. The binding affinity of 64Cu-NOTA-mAb109 in A549 cells was determined to be 29.64 nM. 64Cu-NOTA-mAb109 displayed prominent tumor accumulation from 2 h to 60 h p.i. (9.34 ± 0.67 %ID/g). NIRF imaging of Cy5.5-mAb109 showed high accumulation till 9 days p.i., while tumors nearly can not be observed in negative groups, which was confirmed by autoradiography. Immunohistological study confirmed that mAb109 had strong and specific capacity to bind lung adenocarcinoma (concentration to 58 nM). Our study demonstrated mAb109 was a new platform for the development of novel agent for lung adenocarcinoma noninvasive imaging. The resulted 64Cu-NOTA-mAb109/Cy5.5-mAb109 show favorable imaging properties/specificity for A549 tumor and high sensitivity to human lung adenocarcinoma tissues.

A multi-targeting natural product, aiphanol, inhibits tumor growth and metastasis.

Cancer is one of the main causes of death in humans worldwide, the development of more effective anticancer drugs that can inhibit the malignant progression of cancer cells is of great significance. Aiphanol is a natural product identified from the seeds of Arecaceae and the rhizome of Smilax glabra Roxb. Our preliminary studies revealed that it had potential antiangiogenic and antilymphangiogenic activity by directly targeting VEGFR2/3 and COX2 in endothelial cells. However, the influence of aiphanol on cancer cells per se remains largely undefined. In this study, the effects and related mechanisms of aiphanol on cancer growth and metastasis were evaluated in vitro and in vivo. Acute toxicity assay and pharmacokinetic analysis were utilized to investigate the safety profile and metabolism characteristics of aiphanol. We revealed that aiphanol inhibited the proliferation of various types of cancer cells and the growth of xenograft tumors in mice and zebrafish models. The possible mechanism was associated with the inactivation of multiple kinases, including FAK, AKT and ERK, and the upregulation of BAX and cleaved caspase-3 to promote cancer cell apoptosis. Aiphanol significantly inhibited cancer cell migration and invasion, which was related to the inhibition of epithelial-mesenchymal transition (EMT) and F-actin aggregation. Aiphanol effectively attenuated the metastasis of several types of cancer cells in vivo. In addition, aiphanol exerted no significant toxicity and had fast metabolism. Collectively, we demonstrated the anticancer effects of aiphanol and suggested that aiphanol has potential as a safe and effective therapeutic agent to treat cancer.

A high-throughput screening system for G-protein-coupled receptors using ß-lactamase enzyme complementation technology.

AIM: to establish a system for monitoring the activation of G-protein-coupled receptors (GPCRs) using ß-lactamase enzyme fragment complementation (EFC) technology. METHODS: two inactive ß-lactamase deletion fragments, bla(a) and bla(b), were fused to ß-arrestin and GPCR, respectively. A stable cell line named HEK/293-ß2a2, which expressed two fusion proteins, GPCR/bla(b) and ß-arrestin2/bla(a), was generated under antibiotic selection. A natural compound library of high performance liquid chromatography (HPLC)-fractionated samples from the ethanol extracts of Chinese medicinal herbs was used for high-throughput screening (HTS) of ß2-adrenoceptor (ß2AR) agonists against the cell line HEK/293-ß2a2. The interested hits were validated by the measurement of second-messenger cyclic adenosine monophosphate (cAMP) production. RESULTS: the stable cell line HEK/293-ß2a2 responded to ß2AR agonist/antagonist in a dose-dependent manner. The EC(50) value obtained for isoproterenol was 15.5 nmol/L, and the IC(50) value obtained for propranolol was 51.9 nmol/L. Furthermore, HTS was performed to identify ß2AR agonists from the natural compound library we established. The Z' factor value was determined to be 0.68. Three hits were identified from primary screening and found to be as potent as isoproterenol in a camp assay. CONCLUSION: a cell-based high-throughput functional assay was established to directly monitor the activation of GPCRs based on the interaction between agonist-activated GPCR and ß-arrestin using ß-lactamase EFC technology, which can be used to search for leads in the natural compound library.

Elucidation of the pharmacophore of echinocystic acid, a new lead for blocking HCV entry.

To elucidate the pharmacophore of echinocystic acid (EA), an oleanane-type triterpene displaying substantial inhibitory activity on HCV entry, two microbial strains, Rhizopus chinensis CICC 3043 and Alternaria alternata AS 3.4578, were utilized to modify the chemical structure of EA. Eight new metabolites with regio- and stereo-selective introduction of hydroxyl and lactone groups at various inert carbon positions were obtained. The anti-HCV entry activity of the metabolites 2-13, along with their parental compound EA and other analogs 14-15, were evaluated. Most of the metabolites showed no improvement but detrimental effect on potency except compound 5 and 6, which showed similar and even a litter higher anti-HCV entry activity than that of EA. The results demonstrated that ring A, B, C and the left side of ring E of EA are highly conserved, while ring D and the right side of ring E of EA are flexible. Introduction of a hydroxyl group at C-16 enhanced the triterpene potency. Further analysis indicated that the hemolytic effect of EA disappeared upon such modifications.

A system for screening agonists targeting beta2-adrenoceptor from Chinese medicinal herbs.

In order to develop a model for screening the agonists of human beta(2)-adrenoceptor from Chinese medicinal herbs extracts, we used a cell-based functional assay based on a common G protein-coupled receptor (GPCR) regulation mechanism and destabilized enhanced green fluorescent protein (d(2)EGFP) reporter gene technique. The positive cell clone was confirmed by real-time polymerase chain reaction (PCR) and imaging analysis. To assess the value of this model, we screened over 2000 high performance liquid chromatography (HPLC)-fractionated samples from the ethanol extracts of Chinese medicinal herbs. Six fractions (isolated from Panax japonicus, Veratrum nigrum, Phellodendron amurense, Fructus Aurantii Immaturus, Chaenomeles speciosa, and Dictamnus dasycarpus) showed significant effects on active reporter gene expression, three of which (isolated from Phellodendron amurense, Fructus Aurantii Immaturus, and Chaenomeles speciosa) were selected for further concentration response analysis and the half maximal effective concentration (EC(1/2 max)) values were 4.2, 2.7, and 4.8 microg/ml, respectively. Therefore, this reporter gene assay was suitable for screening beta(2)-adrenoceptor agonists. The results suggest that the six herbal extracts are the possible agonists of beta(2)-adrenoceptor.