Panax notoginseng saponins normalises tumour blood vessels by inhibiting EphA2 gene expression to modulate the tumour microenvironment of breast cancer.

BACKGROUND: Panax notoginseng saponins (PNS), the main active component of Panax notoginseng, can promote vascular microcirculation. PNS exhibits antitumor effects in various cancers. However, the molecular basis of the relationship between PNS and tumor blood vessels remains unclear. PURPOSE: To study the relationship between PNS inhibiting the growth and metastasis of breast cancer and promoting the normalization of blood vessels. METHODS: We performed laser speckle imaging of tumor microvessels and observed the effects of PNS on tumor growth and metastasis of MMTV-PyMT (FVB) spontaneous breast cancer in a transgenic mouse model. Immunohistochemical staining of Ki67 and CD31 was performed for tumors, scanning electron microscopy was used to observe tumor vascular morphology, and flow cytometry was used to detect tumor tissue immune microenvironment (TME). RNA-seq analysis was performed using the main vessels of the tumor tissues of the mice. HUVECs were cultured in tumor supernatant in vitro to simulate tumor microenvironment and verify the sequencing differential key genes. RESULTS: After treatment with PNS, we observed that tumor growth was suppressed, the blood perfusion of the systemic tumor microvessels in the mice increased, and the number of lung metastases decreased. Moreover, the vascular density of the primary tumor increased, and the vascular epidermis was smoother and flatter. Moreover, the number of tumor-associated macrophages in the tumor microenvironment was reduced, and the expression levels of IL-6, IL-10, and TNF-α were reduced in the tumor tissues. PNS downregulated the expression of multiple genes associated with tumor angiogenesis, migration, and adhesion. In vitro tubule formation experiments revealed that PNS promoted the formation and connection of tumor blood vessels and normalized the vessel morphology primarily by inhibiting EphA2 expression. In addition, PNS inhibited the expression of tumor vascular marker proteins and vascular migration adhesion-related proteins in vivo. CONCLUSION: In this study, we found that PNS promoted the generation and connection of tumor vascular endothelial cells, revealing the key role of EphA2 in endothelial cell adhesion and tumor blood vessel morphology. PNS can inhibit the proliferation and metastasis of breast cancer by inhibiting EphA2, improving the immune microenvironment of breast cancer and promoting the normalization of tumor blood vessels.

Sorafenib blocks the activation of the HIF-2α/VEGFA/EphA2 pathway, and inhibits the rapid growth of residual liver cancer following high-intensity focused ultrasound therapy in vivo.

BACKGROUND: Insufficient high-intensity focused ultrasound (HIFU) can promote the rapid progression of the residual tumor through the hypoxia inducible factor-2α +(HIF-2α)/vascular endothelial growth factor A (VEGFA)/ephrin type-A receptor 2 (EphA2) pathway. Although sorafenib has been shown to significantly improve the survival of patients with advanced liver cancer, the use of sorafenib in residual tumor tissues following HIFU has rarely been elucidated. Thus, this study aimed to investigate the potential adjuvant therapeutic effects of sorafenib following HIFU in order to reduce the relapse rate following insufficient HIFU. METHODS: Xenograft tumors were established using nude mice injected with liver cancer cells. At approximately 4 weeks after the inoculation of the tumor cells (tumors reached 1.3-1.5 cm), all mice were randomly divided into 3 groups as follows: i) The control group (no treatment); ii) the HIFU-alone group, and iii) the combination group (HIFU + sorafenib), with 6 mice per group. The residual tumor volume was determined among the different treatment groups. The protein expression levels of HIF-2α, VEGFA and EphA2 were determined by immunohistochemistry and western blotting, and the mRNA levels were detected by RT-qPCR. The microvessel density (MVD) was calculated by CD31 immunohistochemistry staining. RESULTS: The results revealed that by comparing the control group, insufficient HIFU promoted HIF-2α, VEGFA and EphA2 expression (P < 0.05). Compared with the HIFU-alone group, the protein and mRNA levels of HIF-2α, VEGFA and EphA2 were markedly decreased in the group that received combined treatment with HIFU and sorafenib (P < 0.05). Similar results were obtained for MVD expression. Synergistic tumor growth inhibitory effects were also observed between the control group and HIFU group (P < 0.05). CONCLUSIONS: The findings of this study demonstrate that the expression of HIF-2α, VEGFA and EphA2 can be inhibited by sorafenib, and that sorafenib is likely to provide an effective adjunct treatment for patients with HCC following HIFU ablation.

Quantitative phosphoproteomic analysis identifies the potential therapeutic target EphA2 for overcoming sorafenib resistance in hepatocellular carcinoma cells.

Limited therapeutic options are available for advanced-stage hepatocellular carcinoma owing to its poor diagnosis. Drug resistance to sorafenib, the only available targeted agent, is commonly reported. The comprehensive elucidation of the mechanisms underlying sorafenib resistance may thus aid in the development of more efficacious therapeutic agents. To clarify the signaling changes contributing to resistance, we applied quantitative phosphoproteomics to analyze the differential phosphorylation changes between parental and sorafenib-resistant HuH-7 cells. Consequently, an average of ~1500 differential phosphoproteins were identified and quantified, among which 533 were significantly upregulated in resistant cells. Further bioinformatic integration via functional categorization annotation, pathway enrichment and interaction linkage analysis led to the discovery of alterations in pathways associated with cell adhesion and motility, cell survival and cell growth and the identification of a novel target, EphA2, in resistant HuH-7R cells. In vitro functional analysis indicated that the suppression of EphA2 function impairs cell proliferation and motility and, most importantly, overcomes sorafenib resistance. The attenuation of sorafenib resistance may be achieved prior to its development through the modulation of EphA2 and the subsequent inhibition of Akt activity. Binding analyses and in silico modeling revealed a ligand mimic lead compound, prazosin, that could abate the ligand-independent oncogenic activity of EphA2. Finally, data obtained from in vivo animal models verified that the simultaneous inhibition of EphA2 with sorafenib treatment can effectively overcome sorafenib resistance and extend the projected survival of resistant tumor-bearing mice. Thus our findings regarding the targeting of EphA2 may provide an effective approach for overcoming sorafenib resistance and may contribute to the management of advanced hepatocellular carcinoma.

[Inhibitory effect of Qilan Capsules on the expressions of vasculogenic mimicry-related proteins in prostate cancer].

Objective: To investigate the effect of Qilan Capsules (QLC) on the expressions of the related proteins HIF-1α, VEGF-α, EphA2 and MMP-1 in the formation of vasculogenic mimicry (VM) in prostate cancer. METHODS: Prostate cancer PC-3 cells were cultured, transfected with siRNA, and divided into eight groups, blank control, HIF-1α siRNA, VEGF-α siRNA, EphA2 siRNA, QLC intervention, QLC + HIF-1α siRNA, QLC + VEGF-α siRNA, and QLC + EphA2 siRNA. The expressions of the HIF-1α, VEGF-α and EphA2 proteins in the pathway of VEGF were determined by Western blot. RESULTS: Compared with the blank control group, the expression of HIF-1α was evidently decreased in the HIF-lα siRNA and QLC + HIF-lα siRNA groups (0.624 7 ± 0.042 8 vs 0.032 8 ± 0.002 5 and 0.036 8 ± 0.018 1, P < 0.05), so were that of VEGF-α in the VEGF-α siRNA and QLC + VEGF-α siRNA groups (0.068 9 ± 0.005 1 vs 0.016 9 ± 0.000 7 and 0.010 9 ± 0.000 8, P < 0.05), that of EphA2 in the EphA2 siRNA and QLC + EphA2 siRNA groups though with no statistically significant difference (0.1684 ± 0.0126 vs 0.134 5 ± 0.028 6 and 0.165 4 ± 0.039 8, P > 0.05), and that of MMP-1 in the HIF-lα siRNA, VEGF-α siRNA and EphA2 siRNA groups (1.696 1 ± 0.152 7 vs 0.435 9 ± 0.036 9, 0.198 7 ± 0.009 0 and 0.0218 ± 0.000 7, P < 0.05). CONCLUSIONS: Qilan Capsules can suppress VM formation in prostate cancer by inhibiting the expressions of HIF-1α, VEGF-α and MMP-1, which plays a role in the clinical treatment of prostate cancer by checking the growth and development of the blood supply system in the tumor tissue.

Ophiopogonin B suppresses the metastasis and angiogenesis of A549 cells in vitro and in vivo by inhibiting the EphA2/Akt signaling pathway.

Lung adenocarcinoma is the most common metastatic cancer, and is associated with high patient mortality. Therefore, investigation of anti­metastatic treatments for lung adenocarcinoma is crucial. Ophiopogonin B (OP­B) is a bioactive component of Radix Ophiopogon Japonicus, which is often used in Chinese traditional medicine to treat pulmonary disease. Screening of transcriptome and digital gene expression (DGE) profiling data in NSCLC cell lines showed that OP­B regulated the epithelial­mesenchymal transition (EMT) pathway in A549 cells. Further results showed that 10 µmol/l OP­B downregulated EphA2 expression and phosphorylation (Ser897) in A549 cells but upregulated them in NCI­H460 cells. Meanwhile, the Ras/ERK pathway was unaffected in A549 cells and stimulated in NCI­H460 cells. More importantly, detection of the EMT pathway showed that OP­B treatment increased the epithelial markers ZO­1 and E­cadherin and decreased the expression of the mesenchymal marker N­cadherin and the transcriptional repressors Snail, Slug and ZEB1. Furthermore, through Transwell migration and scratch wound healing assays, we found that 10 µmol/l OP­B significantly reduced the invasion and migration of A549 cells. In vivo, we found that 75 mg/kg OP­B inhibited A549 cell metastasis in a pulmonary metastasis nude mouse model. In addition, we also found that 10 µmol/l OP­B significantly inhibited tube formation in EA.hy926 cells. The expression of VEGFR2 and Tie­2, the phosphorylation of Akt (S473) and PLC (S1248), and the levels of EphA2 and phosphorylated EphA2 (S897) were all inhibited by OP­B in this cell line. In vivo, using a Matrigel plug assay, we found that OP­B inhibited angiogenesis and the hemoglobin content of A549 transplanted tumors. Taken together, OP­B inhibited the metastasis and angiogenesis of A549 cells by inhibiting EphA2/Akt and the corresponding pathway. The investigation gives new recognition to the anticancer mechanism of OP­B in NSCLC and this compound is a promising inhibitor of metastasis and angiogenesis of lung adenocarcinoma cells.

17ß-estradiol attenuates ovariectomy­induced bone deterioration through the suppression of the ephA2/ephrinA2 signaling pathway.

The present study aimed to investigate whether 17ß­estradiol (E2) exerts protective effects on bone deterioration induced by ovariectomy (OVX) through the ephA2/ephrinA2 signaling pathway in rats. Female rats were subjected to OVX, sham surgeryor OVX+E2 treatment. Levels of biomarkers were measured in serum and urine. Hematoxylin and eosin staining was performed on paraffin­embedded bone sections. Expression of genes and proteins was analyzed by reverse transcription­quantitative polymerase chain reaction and western blotting, respectively. Bone mineral density (BMD) was analyzed by dual­energy X­ray absorptiometry. Trabecular bone microarchitecture was also evaluated. Osteoclastogenesis was induced by in vitro culturing with mouse receptor activator of nuclear factor κB ligand (RANKL) and macrophage colony­stimulating factor 1. small interfering RNA was designed to knockdown ehpA2 receptor and its ligand ephrinA2. Results of the present study demonstrated that E2 had suppressive effects on OVX­induced body weight gain and bone turnover factors in serum and urine. E2 inhibited the bone resorption function of osteoclasts by inhibiting the production of tartrate­resistant acid phosphatase­5b and RANKL, and induced bone formation function of osteoblasts by prompting runt­related transcription factor 2, Sp7 transcription factor and collagen alpha­1(I) chain expression in bone marrow cells. E2 treatment significantly increased the tibia BMD and prevented the deterioration of trabecular microarchitecture compared with the OVX group. Moreover, E2 significantly decreased the OVX­stimulated expression of ephA2 and ephrinA2. EphA2 or ephrin A2 knockdown significantly suppressed osteoclastogenesis in vitro. In conclusion, E2 can attenuate OVX­induced bone deterioration partially through the suppression of the ephA2/ephrinA2 signaling pathway. Therefore EphA2/ephrinA2 signaling pathway may be a potential target for osteoporosis treatment.

Inhibitory effect of Qilan Capsules on the expressions of vasculogenic mimicry-related proteins in prostate cancer / 中华男科学杂志

<p><b>Objective</b>To investigate the effect of Qilan Capsules (QLC) on the expressions of the related proteins HIF-1α, VEGF-α, EphA2 and MMP-1 in the formation of vasculogenic mimicry (VM) in prostate cancer.</p><p><b>METHODS</b>Prostate cancer PC-3 cells were cultured, transfected with siRNA, and divided into eight groups, blank control, HIF-1α siRNA, VEGF-α siRNA, EphA2 siRNA, QLC intervention, QLC + HIF-1α siRNA, QLC + VEGF-α siRNA, and QLC + EphA2 siRNA. The expressions of the HIF-1α, VEGF-α and EphA2 proteins in the pathway of VEGF were determined by Western blot.</p><p><b>RESULTS</b>Compared with the blank control group, the expression of HIF-1α was evidently decreased in the HIF-lα siRNA and QLC + HIF-lα siRNA groups (0.624 7 ± 0.042 8 vs 0.032 8 ± 0.002 5 and 0.036 8 ± 0.018 1, P < 0.05), so were that of VEGF-α in the VEGF-α siRNA and QLC + VEGF-α siRNA groups (0.068 9 ± 0.005 1 vs 0.016 9 ± 0.000 7 and 0.010 9 ± 0.000 8, P < 0.05), that of EphA2 in the EphA2 siRNA and QLC + EphA2 siRNA groups though with no statistically significant difference (0.1684 ± 0.0126 vs 0.134 5 ± 0.028 6 and 0.165 4 ± 0.039 8, P > 0.05), and that of MMP-1 in the HIF-lα siRNA, VEGF-α siRNA and EphA2 siRNA groups (1.696 1 ± 0.152 7 vs 0.435 9 ± 0.036 9, 0.198 7 ± 0.009 0 and 0.0218 ± 0.000 7, P < 0.05).</p><p><b>CONCLUSIONS</b>Qilan Capsules can suppress VM formation in prostate cancer by inhibiting the expressions of HIF-1α, VEGF-α and MMP-1, which plays a role in the clinical treatment of prostate cancer by checking the growth and development of the blood supply system in the tumor tissue.</p>

Effect of magnolol on cerebral injury and blood brain barrier dysfunction induced by ischemia-reperfusion in vivo and in vitro.

Magnolol, a neolignan compound isolated from traditional Chinese medicine Magnolia officinalis, has a potentially therapeutic influence on ischemic stroke. Previous studies have demonstrated that cerebral ischemia-reperfusion (I-R) and blood-brain barrier (BBB) are involved in the pathogeneses of stroke. Therefore, in vivo and in vitro studies were designed to investigate the effects of magnolol on I-R-induced neural injury and BBB dysfunction. In cerebral I-R model of mice, cerebral infarct volumes, brain water content, and the exudation of Evans blue were significantly reduced by intravenous injection with magnolol at the doses of 1.4, 7.0, and 35.0 µg/kg. When primary cultured microglial cells were treated with 1 µg/ml lipopolysaccharide (LPS) plus increasing concentrations of magnolol, ranging from 0.01 to 10 µmol/L, magnolol could statistically inhibit LPS-induced NO release, TNF-α secretion, and expression of p65 subunit of NF-κB in the nucleus of microglial cells. In the media of brain microvascular endothelial cells (BMECs), oxygen and glucose deprivation-reperfusion (OGD-R) could remarkably lead to the elevation of TNF-α and IL-1ß levels, while magnolol evidently reversed these effects. In BBB model in vitro, magnolol dose- and time-dependently declined BBB hyperpermeability induced by oxygen and glucose deprivation (OGD), OGD-R, and ephrin-A1 treatment. More importantly, magnolol could obviously inhibit phosphorylation of EphA2 (p-EphA2) not only in ephrin-A1-treated BMECs but also in cerebral I-R model of mice. In contrast to p-EphA2, magnolol significantly increased ZO-1 and occludin levels in BMECs subjected to OGD. Taken together, magnolol can protect neural damage from cerebral ischemia- and OGD-reperfusion, which may be associated with suppressing cerebral inflammation and improving BBB function.

Preclinical Mammalian Safety Studies of EPHARNA (DOPC Nanoliposomal EphA2-Targeted siRNA).

To address the need for efficient and biocompatible delivery systems for systemic siRNA delivery, we developed 1,2-Dioleoyl-sn-Glycero-3-Phosphatidylcholine (DOPC) nanoliposomal EphA2-targeted therapeutic (EPHARNA). Here, we performed safety studies of EPHARNA in murine and primate models. Single dosing of EPHARNA was tested at 5 concentrations in mice (N = 15 per group) and groups were sacrificed on days 1, 14, and 28 for evaluation of clinical pathology and organ toxicity. Multiple dosing of EPHARNA was tested in mice and Rhesus macaques twice weekly at two dose levels in each model. Possible effects on hematologic parameters, serum chemistry, coagulation, and organ toxicity were assessed. Following single-dose EPHARNA administration to mice, no gross pathologic or dose-related microscopic findings were observed in either the acute (24 hours) or recovery (14 and 28 days) phases. The no-observed-adverse-effect level (NOAEL) for EPHARNA is considered >225 µg/kg when administered as a single injection intravenously in CD-1 mice. With twice weekly injection, EPHARNA appeared to stimulate a mild to moderate inflammatory response in a dose-related fashion. There appeared to be a mild hemolytic reaction in the female mice. In Rhesus macaques, minimal to moderate infiltration of mononuclear cells was found in some organs including the gastrointestinal tract, heart, and kidney. No differences attributed to EPHARNA were observed. These results demonstrate that EPHARNA is well tolerated at all doses tested. These data, combined with previously published in vivo validation studies, have led to an ongoing first-in-human phase I clinical trial (NCT01591356). Mol Cancer Ther; 16(6); 1114-23. ©2017 AACR.

Clostridium perfringens enterotoxin as a potential drug for intravesical treatment of bladder cancer.

The current intravesical treatment of bladder cancer (BC) is limited to a few chemotherapeutics that show imperfect effectiveness and are associated with some serious complications. Thus, there is an urgent need for alternative therapies, especially for patients with high-risk non-muscle invasive (NMIBC). Clostridium perfringens enterotoxin (CPE), cytolytic protein binds to its receptors: claudin 3 and 4 that are expressed in epithelial cells. This binding is followed by rapid cell death. Claudin 4 is present in several epithelial tissue including bladder urothelium and its expression is elevated in some forms of BC. In addition to directly targeting BC cells, binding of CPE to claudins increases urothelium permeability that creates conditions for better accession of the tumor. Therefore, we evaluated CPE as a candidate for intravesical treatment of BC using a cellular model. We examined cytotoxicity of CPE against BC cells lines and 3D cultures of cells derived from surgical samples. To better elucidate cellular mechanisms, activated by CPE and to consider the use of CPE non-toxic fragment (C-CPE) for combination treatment with other drugs we synthesized C-CPE, compared its cytotoxic activity with CPE and examined claudin 4 expression and intracellular localization after C-CPE treatment. CPE induced cell death after 1 h in low aggressive RT4 cells, in moderately aggressive 5637 cells and in the primary 3D cultures of BC cells derived from NMIBC. Conversely, non-transformed urothelial cells and cells derived from highly aggressive tumor (T24) survived this treatment. The reason for this resistance to CPE might be the lower expression of CLDNs or their inaccessibility for CPE in these cells. C-CPE treatment for 48 h did not affect cell viability in tested cells, but declined expression of CLDN4 in RT4 cells. C-CPE increased sensitivity of RT4 cells to Mitommycin C and Dasatinib. To better understand mechanisms of this effect we examined expression and phosphorylation status of EphA2 and Src after C-CPE treatment and found changes in expression and phosphorylated status of these regulatory molecules. These observations show that after additional preclinical studies CPE and C-CPE in combinations with other drugs can be considered as a potential modalities for intravesical treatment of BC because of its ability to effectively destroy BC cells expressing claudin 4 and low toxicity against normal urothelium.

Targeting Nanomedicines to Prostate Cancer: Evaluation of Specificity of Ligands to Two Different Receptors In Vivo.

PURPOSE: This manuscript utilised in vivo multispectral imaging to demonstrate the efficacy of two different nanomedicine formulations for targeting prostate cancer. METHODS: Pegylated hyperbranched polymers were labelled with fluorescent markers and targeting ligands against two different prostate cancer markers; prostate specific membrane antigen (PSMA) and the protein kinase, EphrinA2 receptor (EphA2). The PSMA targeted nanomedicine utilised a small molecule glutamate urea inhibitor of the protein, while the EphA2 targeted nanomedicine was conjugated to a single-chain variable fragment based on the antibody 4B3 that has shown high affinity to the receptor. RESULTS: Hyperbranched polymers were synthesised bearing the different targeting ligands. In the case of the EphA2-targeting nanomedicine, significant in vitro uptake was observed in PC3 prostate cancer cells that overexpress the receptor, while low uptake was observed in LNCaP cells (that have minimal expression of this receptor). Conversely, the PSMA-targeted nanomedicine showed high uptake in LNCaP cells, with only minor uptake in the PC3 cells. In a dual-tumour xenograft mouse model, the nanomedicines showed high uptake in tumours in which the receptor was overexpressed, with only minimal non-specific accumulation in the low-expression tumours. CONCLUSIONS: This work highlighted the importance of clearly defining the target of interest in next-generation nanomedicines, and suggests that dual-targeting in such nanomedicines may be a means to achieve greater efficacy.

Preclinical and clinical development of siRNA-based therapeutics.

The discovery of RNA interference, first in plants and Caenorhabditis elegans and later in mammalian cells, led to the emergence of a transformative view in biomedical research. Knowledge of the multiple actions of non-coding RNAs has truly allowed viewing DNA, RNA and proteins in novel ways. Small interfering RNAs (siRNAs) can be used as tools to study single gene function both in vitro and in vivo and are an attractive new class of therapeutics, especially against undruggable targets for the treatment of cancer and other diseases. Despite the potential of siRNAs in cancer therapy, many challenges remain, including rapid degradation, poor cellular uptake and off-target effects. Rational design strategies, selection algorithms, chemical modifications and nanocarriers offer significant opportunities to overcome these challenges. Here, we review the development of siRNAs as therapeutic agents from early design to clinical trial, with special emphasis on the development of EphA2-targeting siRNAs for ovarian cancer treatment.

Metabolite profiling of polyphenols in a Terminalia chebula Retzius ayurvedic decoction and evaluation of its chemopreventive activity.

ETHNOPHARMACOLOGICAL RELEVANCE: The decoction of Terminalia chebula fruit is an ayurvedic remedy whose prolonged oral administration is prized as a generic intestinal and hepatic detoxifying agent. Its administration is suggested also under the perspective of a reduced risk of cancer, metabolic and cardiovascular diseases. AIM OF THE STUDY: To evaluate the phytochemical profile and the chemopreventive potential of Terminalia chebula fruit decoction prepared according to the ayurvedic decoction recipe. MATERIALS AND METHODS: The quali- and quantitative metabolite profiling of polyphenols was obtained using HPLC-UV/DAD and HPLC-ESI-MS. The crude decoction and purified compounds were tested for their capability to interact with the EphA2-ephrin-A1 system and for their antimutagenic properties against dietary and environmental mutagens (AA, 2-NF, NaN3, and heterocyclic amines IQ, MeIQ, MeIQx, Glu-P1, Glu-P2,) in the Ames-Salmonella/microsome assay, with and without enzymatic induction. RESULTS: The decoction was found to contain 3,4,6-tri-O-galloyl-d-glucose (55.87 mg/g), chebulic acid (54.03 mg/g), ß-punicalagin (41.25mg/g), corilagin (40.31 mg/g), α-punicalagin (35.55 mg/g), chebulagic acid (29.09 mg/g), gallic acid (27.96 mg/g) 1,3,4,6-tri-O-galloyl-ß-d-glucose (24.25mg/g) chebulinic acid (20.23 mg/g), 1,2,3,4,6-penta-O-galloyl-d-glucose (13.53 mg/g), ellagic acid (8.00 mg/g), 1,6-di-O-galloyl-d-glucose (4.16 mg/g). An inhibitory effect was recorded in both Salmonella typhimurium TA98 and TA100 strains against the mutagenic activity of heterocyclic amines (22-61%), promutagen AA (91-97%) and directly acting mutagen 2-NF (52%) with but not against NaN3 (7%). Galloyl derivatives allowed an inhibition of mutagenicity induced by MeIQ above 80% at 0.01 mol/plate. Both decoction and purified compounds were able to modulate the EphA2-ephrinA1 system, suggesting a potential multiple chemopreventive mechanism. CONCLUSIONS: The traditional ayurvedic decoction of Terminalia chebula may harbour a potential as a safe and low-cost chemopreventive agent at the intestinal level, if administered according to the ayurvedic specifications. Moreover, its recourse may enhance the presence of some polyphenolic constituents.

Polyphenol rich botanicals used as food supplements interfere with EphA2-ephrinA1 system.

The Eph tyrosine kinase receptors and their ephrin ligands play a central role in several human cancers and their deregulated expression or function promotes tumorigenesis, inducing aggressive tumor phenotypes. Green tea extracts (GTE) have been recently found to inhibit Eph-kinase phosphorylation. In order to evaluate the potential contribution of edible and medicinal plants on EphA2-ephrinA1 modulation, 133 commercially available plant extracts used as food supplements, essential and fixed oils were screened with an ELISA-based binding assay. Nine plant extracts, rich of polyphenols, reversibly inhibited binding in a dose-dependent manner (IC50 0.83-24 µg/ml). Functional studies on PC3 prostate adenocarcinoma cells revealed that active extracts antagonized ephrinA1-Fc-induced EphA2-phosphorylation at non-cytotoxic concentrations (IC50 0.31-11.3 µg/ml) without interfering with EGF-induced EGFR activation, suggesting a specific effect. These findings could furnish an interesting starting point regarding the potential relationship between diet, edible plant secondary metabolites and Eph-ephrin system, suggesting their possible involvement in cancer development modulation.

Internalizing cancer antibodies from phage libraries selected on tumor cells and yeast-displayed tumor antigens.

A number of approaches have been utilized to generate antibodies to cancer cell surface receptors that can be used as potential therapeutics. A number of these therapeutic approaches, including antibody-drug conjugates, immunotoxins, and targeted nucleic acid delivery, require antibodies that not only bind receptor but also undergo internalization into the cell upon binding. We previously reported on the ability to generate cancer cell binding and internalizing antibodies directly from human phage antibody libraries selected for internalization into cancer cell lines. While a number of useful antibodies have been generated using this approach, limitations include the inability to direct the selections to specific antigens and to identify the antigen bound by the antibodies. Here we show that these limitations can be overcome by using yeast-displayed antigens known to be associated with a cell type to select the phage antibody output after several rounds of selection on a mammalian cell line. We used this approach to generate several human phage antibodies to yeast-displayed EphA2 and CD44. The antibodies bound both yeast-displayed and mammalian cell surface antigens, and were endocytosed upon binding to mammalian cells. This approach is generalizable to many mammalian cell surface proteins, results in the generation of functional internalizing antibodies, and does not require antigen expression and purification for antibody generation.

Soy phytoestrogens modify DNA methylation of GSTP1, RASSF1A, EPH2 and BRCA1 promoter in prostate cancer cells.

BACKGROUND: The aim of this study was to determine the effects of soy phytoestrogens on the methylation of promoter genes in prostate tumors. The incidence of prostate cancer in Asia is thirty percent lower than in Western countries. Since soy phytoestrogens represent a large portion of the Asian diet, evidence suggests their protective effect against prostate cancer. MATERIALS AND METHODS: In three human prostate cancer cell lines, methylation-specific-PCR was used to determine the effect of soy isoflavones (genistein and daidzein), compared to known demethylating agent 5-azacytidine as control in the promoter regions of glutathione S-transferase P1 (GSTP1), Ras association domain family 1 (RASSF1A), ephrin B2 (EPHB2) and breast cancer 1 (BRCA1) genes. In parallel, immunohistochemistry was used to assess the effects of genistein, daidzein and 5-azacytidine treatment on the corresponding protein expression. RESULTS: All studied promoters, with the exception of that for BRCA1, were strongly methylated without treatment. After treatment by phytoestrogens, demethylation of GSTP1 and EPHB2 promoter regions was observed and an increase in their protein expression was demonstrated by immunohistochemistry. CONCLUSION: Epigenetic modifications of DNA, such as the promoter CpG island demethylation of tumor suppressor genes, might be related to the protective effect of soy on prostate cancer.

Preclinical rationale for combined use of endocrine therapy and 5-fluorouracil but neither doxorubicin nor paclitaxel in the treatment of endocrine-responsive breast cancer.

PURPOSE: Our previous study indicated that concurrent administration of 4-OH-tamoxifen (TAM) and 5-fluorouracil (5-FU), but not doxorubicin (Dox), resulted in additive antitumor effects on endocrine-responsive breast cancer cells. We further clarified the effects of combined administration of endocrine therapy with chemotherapeutic agents in this study. METHODS: Concurrent treatment with 4-OH-TAM and paclitaxel (Ptx) was investigated in estrogen receptor (ER)-positive breast cancer cells. Additionally, the combined effects of estrogen depletion from culture medium mimicking estrogen ablative therapy with 5-FU, Dox, and Ptx were investigated. RESULTS: Concurrent treatment with 4-OH-TAM and Ptx yielded less than additive antitumor effects in ER-positive breast cancer cells, as observed with Dox in our previous study. More interestingly, estrogen depletion with 5-FU, but with neither Dox nor Ptx, yielded additive antitumor effects on these cells. We also performed preliminary experiments to elucidate the mechanisms of action responsible for the combined antitumor effects observed. Ptx upregulated the level of expression of one of the molecules related to TAM resistance, Eph-A2, as observed with Dox in our previous study. Estrogen depletion down-regulated the level of expression of one of the molecules related to 5-FU resistance, thymidylate synthase, as observed with 4-OH-TAM in our previous study. CONCLUSIONS: These findings, together with those of our previous study, suggest that concurrent treatment with endocrine therapy, administration of TAM, or estrogen ablative therapy and 5-FU but neither Dox nor Ptx may yield additive antitumor effects on endocrine-responsive breast cancer.

Blockade of EphA receptor tyrosine kinase activation inhibits vascular endothelial cell growth factor-induced angiogenesis.

Angiogenesis is a multistep process involving a diverse array of molecular signals. Ligands for receptor tyrosine kinases (RTKs) have emerged as critical mediators of angiogenesis. Three families of ligands, vascular endothelial cell growth factors (VEGFs), angiopoietins, and ephrins, act via RTKs expressed in endothelial cells. Recent evidence indicates that VEGF cooperates with angiopoietins to regulate vascular remodeling and angiogenesis in both embryogenesis and tumor neovascularization. However, the relationship between VEGF and ephrins remains unclear. Here we show that interaction between EphA RTKs and ephrinA ligands is necessary for induction of maximal neovascularization by VEGF. EphA2 RTK is activated by VEGF through induction of ephrinA1 ligand. A soluble EphA2-Fc receptor inhibits VEGF-, but not basic fibroblast growth factor-induced endothelial cell survival, migration, sprouting, and corneal angiogenesis. As an independent, but complementary approach, EphA2 antisense oligonucleotides inhibited endothelial expression of EphA2 receptor and suppressed ephrinA1- and VEGF-induced cell migration. Taken together, these data indicate an essential role for EphA receptor activation in VEGF-dependent angiogenesis and suggest a potential new target for therapeutic intervention in pathogenic angiogenesis.

Involvement of EphA2 in the formation of the tail notochord via interaction with ephrinA1.

Eph receptors have been implicated in cell-to-cell interaction during embryogenesis. We generated EphA2 mutant mice using a gene trap method. Homozygous mutant mice developed short and kinky tails. In situ hybridization using a Brachyury probe found the notochord to be abnormally bifurcated at the caudal end between 11.5 and 12.5 days post coitum. EphA2 was expressed at the tip of the tail notochord, while one of its ligands, ephrinA1, was at the tail bud in normal mice. In contrast, EphA2-deficient notochordal cells were spread broadly into the tail bud. These observations suggest that EphA2 and its ligands are involved in the positioning of the tail notochord through repulsive signals between cells expressing these molecules on the surface.

Characterization of a novel Src-like adapter protein that associates with the Eck receptor tyrosine kinase.

The Eph family of receptor protein tyrosine kinases (RPTKs) is the largest family of RPTKs. The signal transduction pathways initiated by this family have only recently begun to be explored. Using a yeast two-hybrid screen to identify molecules that interact with the cytoplasmic domain of Eck, it was previously shown that activated Eck RPTK bound to and stimulated phosphatidylinositol 3-kinase (Pandey, A., Lazar, D.F., Saltiel, A. R., and Dixit, V.M. (1994) J. Biol. Chem. 269, 30154-30157). Also isolated from this same screen was a novel protein containing SH3 and SH2 adapter modules that had striking homology to those found in the Src family of non-receptor tyrosine kinases. However, unlike other Src family members, it lacked a catalytic tyrosine kinase domain. Hence, this protein was designated SLAP for Src-like adapter protein. Using glutathione S-transferase fusion Proteins, it was demonstrated that SLAP bound to activated Eck receptor tyrosine kinase. Therefore, SLAP is a novel candidate downstream signaling intermediate and the first member of the Src family that resembles an adapter molecule.