Tumor-Derived Microvesicles Induce Proangiogenic Phenotype in Endothelial Cells via Endocytosis

Background: Increasing evidence indicates that tumor endothelial cells (TEC) differ from normal endothelial cells (NEC). Our previous reports also showed that TEC were different from NEC. For example, TEC have chromosomal abnormality and proangiogenic properties such as high motility and proliferative activity. However, the mechanism by which TEC acquire a specific character remains unclear. To investigate this mechanism, we focused on tumor-derived microvesicles (TMV). Recent studies have shown that TMV contain numerous types of bioactive molecules and affect normal stromal cells in the tumor microenvironment. However, most of the functional mechanisms of TMV remain unclear. Methodology/Principal Findings: Here we showed that TMV isolated from tumor cells were taken up by NEC through endocytosis. In addition, we found that TMV promoted random motility and tube formation through the activation of the phosphoinositide 3-kinase/Akt pathway in NEC. Moreover, the effects induced by TMV were inhibited by the endocytosis inhibitor dynasore. Our results indicate that TMV could confer proangiogenic properties to NEC partly via endocytosis. Conclusion: We for the first time showed that endocytosis of TMV contributes to tumor angiogenesis. These findings offer new insights into cancer therapies and the crosstalk between tumor and endothelial cells mediated by TMV in the tumor microenvironment

Dual-ligand modification of PEGylated liposomes shows better cell selectivity and efficient gene delivery

The objective of this study was to develop an efficient dual-ligand based PEGylated liposomal delivery system that had target specificity as well as properties that would enhance cellular uptake. PEGylated liposomes (PEG-LP) were prepared by the lipid film hydration method by adding distearoyl phosphoethanolamine-polyethylene-glycol-2000 conjugate (DSPE-PEG2000) to a lipid mixture. The cyclic RGD (Arg-Gly-Asp) peptide, a specific ligand with affinity for Integrin αvβ3 was coupled to the distal end of the PEG on the PEG-LP (RGD-PEG-LP). Stearylated octaarginine (STR-R8) was incorporated on the surface of the RGD-PEG-LP as dual-ligand (R8/RGD-PEG-LP) that functions as a cell penetrating peptide (CPP). RGD-PEG-LP and R8/RGD-PEG-LP were preferentially taken up by caveolae-mediated and clathrin-mediated endocytosis pathways, respectively. Compared to PEG-LP, R8/RGD-PEG-LP showed an enhanced cellular uptake as well as a higher transfection efficiency in Integrin αvβ3 expressing cells. However, the amount of cellular uptake or gene expression by the single ligand versions was negligible, even in Integrin αvβ3 expressing cells. No remarkable difference in cellular uptake or gene expression was observed for cells in which the expression of targeted receptors was absent. It can be concluded that dual-ligand modified PEG-LP possesses a strong capability for the efficient internalization of PEG-LP and consequently would be an effective tool for the targeted delivery of macromolecules or chemotherapeutics through accelerated cellular uptake

The effect of liposomal size on the targeted delivery of doxorubicin to Integrin alpha v beta 3-expressing tumor endothelial cells

Size of the liposomes (LPs) specially governs its biodistribution. In this study, LPs were developed with controlled sizes, where variation in LP size dictates the ligand receptor interaction, cellular internalization and its distribution within the tumor microenvironment. The therapeutic efficacies of doxorubicin (DOX)-loaded RGD modified small size (similar to 100 nm in diameter, dnm) and large size (similar to 300 dnm) PEGylated LPs (RGD-PEG-LPs) were compared to that of Doxil (a clinically used DOX-loaded PEG-LP, similar to 100 dnm) in DOX resistant OSRC-2 (Renal cell carcinoma, RCC) tumor xenografts. Doxil, which accumulated in tumor tissue via the enhanced permeability and retention (EPR) effect, failed to suppress tumor growth. Small size RGD-PEG-LP, that targets the tumor endothelial cells (TECs) and extravasates to tumor cells, failed to provide anti-tumor effect. Large size RGD-PEG-LP preferentially targets the TECs via minimization of the EPR effect, and significantly reduced the tumor growth, which was exerted through its strong anti-angiogenic activity on the tumor vasculature rather than having a direct effect on DOX resistant RCC. The prepared large size RGD-PEG-LP that targets the TECs via interacting with Integrin alpha v beta 3, is a potentially effective and alternate therapeutic strategy for the treatment of DOX resistant tumor cells by utilizing DOX, in cases where Doxil is ineffective. (C) 2013 Elsevier Ltd. All rights reserved

Design of a dual-ligand system using a specific ligand and cell penetrating peptide, resulting in a synergistic effect on selectivity and cellular uptake

In this study, a dual-ligand liposomal system comprised of a specific ligand and a cell penetrating peptide (CPP) is described to enhance selectivity and cellular uptake. Dual-ligand PEGylated liposomes were prepared by modifying the end of the PEG with an NGR motif peptide, followed by a surface coating of the liposomes with stearylated oligoarginine (STR-RX) The NGR motif recognizes CD13. a marker protein located on tumor endothelial cells A suitable number of RX units was determined to be R4, since it can be masked by the PEG aqueous layer Although no enhanced cellular uptake was observed when a single modification of PEGylated liposomes with either NGR- or STR-R4 was used, the dual-modification with NGR and STR-R4 stimulated uptake of PEGylated liposomes by CD13 positive cells, and this uptake was superior to that obtained by PEG-unmodified liposomes modified with STR-R4 The dual-ligand system shows a synergistic effect on cellular uptake Collectively, the dual-ligand system promises to be useful in the development efficient and specific drug delivery systems. (C) 2010 Elsevier B V All rights reserved

A liposomal delivery system that targets liver endothelial cells based on a new peptide motif present in the ApoB-100 sequence

Liver dysfunction is associated with a variety of liver diseases, including viral or alcoholic hepatitis, fibrosis, cirrhosis, and portal hypertension. A targeted drug delivery system would be very useful in the treatment of these diseases. We herein describe the development of a system comprised of a new peptide-lipid conjugate for the efficient delivery of molecules to LEC. The RLTRKRGLK sequence (3359-3367), which mediates the association of LDL with arterial CSPG and an LDL receptor, was utilized as a ligand for achieving this goal. The peptide modified PEG-LPs (RLTR-PEG-LPs) were efficiently taken up by primary liver endothelial cells (liver ECs) and other types of cells. In vivo biodistribution and confocal microscopy analysis showed that RLTR-PEG-LPs became widely accumulated in LECs within a short time. Distribution of RLTR-PEG-LPs was greatly reduced with a pretreatment of unlabeled RLTR-PEG-LPs, not cationic LPs, indicating that the sequence is important for LECs. The findings indicate that a reverse sequence of RLTR (KLGR) modified PEG-LPs (KLGR-PEG-LP) did the same pattern compared with RLTR-PEG- LPs, suggesting that the RKR or RXXR sequence might be essential for LECs targeting. Collectively RLTR-PEG-LPs and KLGR-PEG-LPs have the potential for delivering drugs to LECs. (C) 2013 Elsevier B.V. All rights reserved

Rapid internal root resorption of the permanent incisor teeth after trauma : a case report

Internal root resorption of permanent teeth is a rare condition. Although its etiology and pathogenesis are not fully understood, trauma has been considered a contributing factor. The treatment and prognosis of internal root resorption of permanent teeth is very challenging. In this report, we describe a patient who experienced internal root resorption of the permanent incisors soon after a traumatic episode. This suggests conservation of permanent teeth may be enhanced by early detection and treatment of this condition

Size-controlled, dual-ligand modified liposomes that target the tumor vasculature show promise for use in drug-resistant cancer therapy

Anti-angiogenic therapy is a potential chemotherapeutic strategy for the treatment of drug resistant cancers. However, a method for delivering such drugs to tumor endothelial cells remains to be a major impediment to the success of anti-angiogenesis therapy. We designed liposomes (LPs) with controlled diameter of around 300 nm, and modified them with a specific ligand and a cell penetrating peptide (CPP) (a dual-ligand LP) for targeting CD13-expressing neovasculature in a renal cell carcinoma (RCC). We modified the LPs with an NGR motif peptide on the top of poly(ethylene glycol) and tetra-arginine (R4) on the surface of the liposome membrane as a specific and CPP ligand, respectively. The large size prevented extravasation of the dual-ligand LP, which allowed it to associate with target vasculature. While a single modification with either the specific or CPP ligand showed no increase in targetability, the dual-ligand enhanced the amount of delivered liposomes after systemic administration to OS-RC-2 xenograft mice. The anti-tumor activity of a dual-ligand LP encapsulating doxorubicin was evaluated and the results were compared with Doxil®, which is clinically used to target tumor cells. Even though Doxil showed no anti-tumor activity, the dual-ligand LP suppressed tumor growth because the disruption of tumor vessels was efficiently induced. The comparison showed that tumor endothelial cells (TECs) were more sensitive to doxorubicin by 2 orders than RCC tumor cells, and the disruption of tumor vessels was efficiently induced. Collectively, the dual-ligand LP is promising carrier for the treatment of drug resistant RCC via the disruption of TECs

Significance of anti-angiogenic therapy in head and neck cancer—Heterogeneity of tumor endothelium

Tumor angiogenesis is necessary for solid tumor progression and metastasis. Thus, targeting tumor blood vessels is an important strategy for cancer therapy. Especially, it would give large benefit to head and neck cancer patients if ideal anti-angiogenic drug is developed. Tumor blood vessels have been shown to differ from their normal counterparts, for example, by changes in morphology. An important concept in tumor angiogenesis is that tumor endothelial cells are assumed to be genetically normal, even though these endothelial cells are structurally and functionally abnormal. To date, many anti-angiogenic drugs have been developed, but it has been also reported to cause toxic side effects. To develop ideal anti-angiogenic therapies, understanding tumor endothelial cell abnormalities is important. We have isolated tumor endothelial cells from mouse tumor xenografts and have shown that tumor endothelial cells are abnormal. Tumor endothelial cells upregulate many genes, such as epidermal growth factor receptor. Tumor endothelial cells are also more sensitive to EGF. Unexpectedly, tumor endothelial cells were cytogenetically abnormal. In marked contrast, freshly isolated normal endothelial cells were diploid. We conclude that tumor endothelial cells can acquire cytogenetic abnormalities while in the tumor microenvironment. Here, we provide an overview of the current studies on tumor endothelial cell abnormalities

Current international consensus on burning mouth syndrome : systematic review of recent review articles

Burning mouth syndrome (BMS) is a type of chronic orofacial pain, which is difficult to diagnose and treat. Patients suffer from BMS worldwide. The pathophysiology of this disorder is not fully understood. This study looked at recent review articles about the classifications, diagnosis and pathophysiology of BMS. PubMed/MEDLINE and WEB of SCIENCE® databases were reviewed to identify articles about BMS, written in English from 2010 to May 2017. Eighteen review articles about BMS were identified, including six systematic reviews, 11 narrative reviews, and one meta-analysis. The most frequently cited classification system for BMS was the International Classification of Headache Disorders (ICHD). Fourteen of the 18 articles (78%) subtyped BMS as primary and secondary BMS, and 16 (89%) of the 18 articles revealed that the main pathophysiology of BMS was pain of neuropathic origin. A review and meta-analysis clearly demonstrated significant relationships between psychological factors and BMS. BMS is most frequently subtyped as primary and secondary. Pain in BMS is regarded as of neuropathic origin, although its etiology may be multifactorial. This paper will discuss these findings and a summary of the reviews will be presented

Construction of an Aptamer Modified Liposomal System Targeted to Tumor Endothelial Cells

We describe herein the development of a high affinity and specific DNA aptamer as a new ligand for use in liposomal nanoparticles to target cultured mouse tumor endothelial cells (mTECs). Active targeted nanotechnology based drug delivery systems are currently of great interest, due to their potential for reducing side effects and facilitating the delivery of cytotoxic drugs or genes in a site specific manner. In this study, we report on a promising aptamer candidate AraHH036 that shows selective binding towards mTECs. The aptamer does not bind to normal cells, normal endothelial cells or tumor cells. Therefore, we synthesized an aptamer-polyethylene glycol (PEG) lipid conjugate and prepared aptamer based liposomes (ALPs) by the standard lipid hydration method. First, we quantified the higher capacity of ALPs to internalize into mTECs by incubating ALPs containing 1 mol%, 5 mol% and 10 mol% aptamer of total lipids and compared the results to those for unmodified PEGylated liposomes (PLPs). A confocal laser scanning microscope (CLSM) uptake study indicated that the ALPs were taken up more efficiently than PLPs. The measured K-d value of the ALPs was 142 nM. An intracellular trafficking study confirmed that most of the rhodamine labeled ALPs were taken up and co-localized with the green lysotracker, thus confirming that they were located in lysosomes. Finally, using an aptamer based proteomics approach, the molecular target protein of the aptamer was identified as heat shock protein 70 (HSP70). The results suggest that these ALPs offer promise as a new carrier molecule for delivering anti-angiogenesis drugs to tumor vasculature