Ovarian cancer is one of the most common gynecological diseases with high mortality rates. Previous studies have shown that microRNA (miR)‑638 is associated with tumorigenesis. The present study aimed to assess the role and underlying mechanisms of miR‑638 in ovarian cancer. miR‑638 expression was detected in ovarian cancer tissues and miR‑638 was overexpressed or knocked down in ovarian cancer OVCAR‑3 and Caov‑3 cells. The clinical results revealed that miR‑638 expression was downregulated in ovarian cancer tissues compared with in adjacent normal tissues. miR‑638 expression was also found to be relatively low in OVCAR‑3 cells whilst being relatively high in Caov‑3 cells among the five ovarian cancer cell lines tested. miR‑638 overexpression inhibited cell viability, arrested the cell cycle at the G1 phase and promoted apoptosis in OVCAR‑3 cells. By contrast, miR‑638 knockdown increased Caov‑3 cell viability, facilitated cell cycle progression and inhibited apoptosis. miR‑638 reduced the expression of high mobility group A1 (HMGA1) by directly targeting its 3' untranslated region. HMGA1 overexpression reversed the inhibition of proliferation induced by miR‑638 overexpression in OVCAR‑3 cells. These results suggest that miR‑638 may serve to be a suppressor of ovarian cancer by regulating HMGA1, which may provide a potential therapeutic target for ovarian cancer.
Abstract Neural crest derived tumors express high levels of a unique class of lipid linked glycan known as gangliosides. Gangliosides are involved in growth factor signaling by regulating complexes in lipid rafts. Genetic studies show that through aberrant expression of gangliosides, these tumors acquire aggressive growth properties. Prior to this research, the only ganglioside inhibitors identified were non-specific and broadly blocked virtually all glycolipid classes. These non-specific glycolipid inhibitors demonstrated anti-cancer activity in animal models of neural crest tumors. However, due to substantial off-target dose-limiting toxicity from lack of specificity for the ganglioside sub-class, they effectively cannot be used in humans for cancer treatment. Selective inhibition of gangliosides without affecting other glycan classes could potentially avoid these problems and provide an effective treatment for neural crest and other ganglioside-dependent tumors. To identify the first known selective inhibitors of gangliosides, we developed a novel molecular screening strategy for identifying selective small-molecule ganglioside inhibitors. This platform identified the first drug-like selective inhibitors of gangliosides. ZP10395, a lead compound, selectively and dose-dependently reduces gangliosides in multiple tumor cell lines and is 10-15 fold more potent than the existing non-specific inhibitors. Importantly, it does not inhibit other glycolipid classes associated with dose-limiting toxicity. Administering ZP10395 to a mouse xenograph melanoma model significantly reduced ganglioside production and slowed tumor growth in the presence of a reduced T-cell response. These results demonstrate the potential utility of specific ganglioside inhibitors for treating ganglioside dependent tumors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2934. doi:10.1158/1538-7445.AM2011-2934
All four members of the human epidermal growth factor (EGF) receptor (HER) family are implicated in human cancers. Although efficacious in a subset of patients, resistance to single-targeted anti-HER therapy [i.e., cetuximab (Erbitux) and trastuzumab (Herceptin)] is often associated with coexpression of other HER family members. This may be overcome by a HER ligand binding molecule that sequesters multiple EGF-like ligands, preventing ligand-dependent receptor activation. Toward this end, we have combined the HER-1/EGFR and HER-3 ligand binding domains, dimerized with fusion of an Fc fragment of human IgG1. This resulted in a mixture of HER-1/Fc homodimer (HFD100), HER-3/Fc homodimer (HFD300), and HER-1/Fc:HER-3/Fc heterodimer (RB200), also termed Hermodulins. The purified first-generation RB200 bound EGF and neuregulin 1 (NRG1)-beta1 ligands, determined by cross-linking and direct binding studies. The binding affinity for both was approximately 10 nmol/L by dissociation-enhanced lanthanide fluorescence immunoassay using europium (Eu)-labeled ligands. Competition studies with RB200 using Eu-EGF or Eu-NRG1-beta1 revealed that RB200 bound HER-1 ligands, including transforming growth factor-alpha and heparin-binding EGF, and HER-3 ligands NRG1-alpha and NRG1-beta3. RB200 inhibited EGF- and NRG1-beta1-stimulated tyrosine phosphorylation of HER family proteins, proliferation of a diverse range of tumor cells in monolayer cell growth assays, tumor cell proliferation as a single agent and in synergy with tyrosine kinase inhibitors, lysophosphatidic acid-stimulated cell proliferation, and tumor growth in two human tumor xenograft nude mouse models. Taken together, the data reveal that RB200 has the potential to sequester multiple HER ligands and interfere with signaling by HER-1, HER-2, and HER-3.
Blue tides at the head of Tokyo Bay are a hydro-environmental phenomenon where seawater appears to be milky blue because of the reflection of the sunlight off surface water containing large amounts of sulphur particles. Its appearance is due to the coastal upwelling of bottom oxygen-depleted water induced by northeasterly wind-driven circulation. Blue tides cause the death of many shellfish and other aquatic animals across the head of Tokyo Bay and consequently result in substantial economic losses to coastal fisheries. This paper examines the occurrence of wind-driven blue tides in Tokyo Bay, based on a simplified hydrodynamic model and observational analysis. The model assumed a two-layer structure with a wind-driven upper layer and an oxygen-depleted lower layer. In this study, we derived a simple analytical solution to determine a critical wind condition for which the lower layer outcrops at the surface if the wind forcing is sufficiently strong, resulting in the mixing of the two layers and giving rise to blue tide. The results of sensitivity analyses of the analytical solution to all incorporated factors were found to be in accordance with a qualitative understanding of the blue tide phenomenon. More importantly, comparisons of observational data with real cases of blue tide during 1978–2016 and without blue tide during 2003–2016 suggested that this analytical solution was mostly valid. This study would be helpful for gaining a better understanding of the hydro-dynamical mechanism of blue tide.
Mutant cell lines provide an excellent model for studying the structure, assembly and function of proteoglycans under the controlled conditions of tissue culture. Numerous proteoglycan-deficient strains have been isolated, mostly in Chinese hamster ovary cells, and in many cases the defects have been characterized both genetically and biochemically (see Table 1). Biochemical analysis of the mutants has confirmed that various enzyme activities detected in cell-free extracts using synthetic substrates actually play a role in proteoglycan assembly in vivo. The cell lines have allowed investigators to study how altering the composition of proteoglycans affects fundamental properties of cells, such as adhesion and signaling. Moreover, animal cell mutants provide the background for predicting the phenotype of organismal mutants defective in proteoglycan assembly. Table 1 Cell Mutants with Defined Defects in Glycosaminoglycan Biosynthesis ComplementationGroup Biochemical Defect Phenotype pgsA (CHO) (28) Xylosyltransferase Glycosaminoglycan-deficient pgsB (CHO) (29) Galactosyltransferase I Glycosaminoglycan-deficient pgsG (CHO) (20) Glucuronosyltransferase I Glycosaminoglycan-deficient pgsD (CHO) (30) N-acetylglucosaminyl/glucuronosyltransferase (EXT-1) Heparan sulfate-deficient Gro2C (mouse L-cells) (3,31) N-acetylglucosaminyl/glucuronosyltransferase (EXT-1) Heparan sulfate-deficient ldlD (CHO) (32,33) UDP-glucose/galactose (GlcNAc/GalNAc) 4-epimerase Chondroitin sulfate-deficient when starved for GalNAc; GAG-deficient when starved for galactose pgsC (CHO) (34) Sulfate transporter Normal glycosaminoglycans; deficient labeling with 35SO4 pgsE (CHO) (35) N-deacetylase/N-sulfotransferase 1 (NDST-1) Undersulfated heparan sulfate CM-15 (COS cells) (36) N-deacetylase/N-sulfotransferase (undefined locus) Undersulfated heparan sulfate pgsF (CHO) (26) 2-O-sulfotransferase Deficient 2-O-sulfation of heparan sulfate
4076 Receptor tyrosine kinases such as members of the HER family are well-validated targets for cancer therapy. However, anti-cancer agents directed at only one HER family member often encounter endogenous or acquired resistance due to multiple HER co-activation or increased production of HER1 or HER3 ligands by tumor cells. To target multiple members of the HER family and block their function, we have developed a novel bi-specific HER1/HER3 heterodimeric ligand trap comprised of optimized HER1 and HER3 extracellular domains fused with the Fc portion of human IgG1. We investigated binding activities of a prototypic Hermodulin, RB200, using europium-labeled ligands to compare ligand binding affinities of RB200 with those of Hermodulin variants obtained via a high throughput rational mutagenesis process (optimized Hermodulins). Our data show that RB200 retains specific binding to various HER ligands, such as EGF, TGF-alpha, HB-EGF and neuregulin (NRG1-beta1) (Kd = 10 to 30 nM). Optimized Hermodulins have improved ligand binding affinities (Kd = 0.5 to 2 nM) for both HER1 and HER3 ligands with greater Bmax. We also developed a sensitive ELISA specific for Hermodulins, and studied the pharmacokinetics in rodent models in order to provide dosing strategies and interpret future studies evaluating the efficacy and tolerability of Hermodulins. RB200 was administered as a single iv or ip dose of 15-30 mg/kg in rats and mice, and plasma samples were analyzed via ELISA. RB200 exhibited high bioavailability, a low volume of distribution, and a prolonged terminal half-life consistent with expectations for Fc-fusion proteins and therapeutic monoclonal antibodies. Together these data suggest that Hermodulins act as bi-specific HER1/HER3 ligand traps and have desirable in vivo pharmacokinetic characteristics. These results support continued development of Hermodulins for cancer therapy.
AACR Centennial Conference: Translational Cancer Medicine-- July 20-23, 2008; Monterey, CA
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Resistance to single-targeted anti-HER agents has been attributed to multiple HER co-activation that occurs through receptor dimerization. We constructed and purified novel molecules comprising HER1/EGFR and HER3 ligand binding domains tethered to a human Ig Fc region. By design, these Hermodulins bind the majority of HER ligands and provide a therapeutic anti-cancer strategy similar to clinically-proven molecules developed for both TNF-alpha and VEGF-related diseases. RB200, a prototypic Hermodulin, was evaluated for activity against a spectrum of cell lines derived from human malignancies. Effects on monolayer cell growth in the presence of serum were measured. Dose-dependent inhibition of cell growth by RB200 was demonstrated in many cell lines. Synergistic growth inhibition in vitro was also demonstrated when RB200 was combined with small molecule tyrosine kinase inhibitors (TKIs) and conventional cytotoxic chemotherapies. Nude mice bearing established subcutaneous human NSCLC tumors, derived from the H1437 tumor cell line, were used to evaluate in vivo activity of RB200. Mice (N=10/group) were treated with RB200, PBS or cetuximab. Tumor sizes were measured via external calipers. These studies showed ~70% inhibition of tumor growth at 10 mg/kg vs. PBS control. Greater anti-tumor effects were observed when RB200 was combined with the TKIs. Optimized versions of Hermodulins with enhanced activity are being developed.
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