Anti-angiogenesis and anti-tumor effects of AdNT4-anginex

HM-3-HSA exhibits potent anti-angiogenesis and antitumor activity in hepatocellular carcinoma

HM-3-HSA is an antitumor fusion protein which improved the pharmacokinetics of HM-3. Previous studies reported that HM-3-HSA enhanced antitumor activity of HM-3 in melanoma cells. However, the efficacy and the mechanism of HM-3-HSA in hepatocellular carcinoma, especially its effect on tumor angiogenesis, have not been elucidated. Herein, we showed that HM-3-HSA significantly inhibited the H22 and SMMC-7721 tumor xenografts growth and tumor angiogenesis in vivo, indicating the antitumor activity exerted by HM-3-HSA was closely corrected with its potency on tumor angiogenesis. To investigate the anti-angiogenic mechanism, we evaluated the efficacy of HM-3-HSA in HUVECs in vitro. The results showed that multiple steps of tumor angiogenesis, including endothelial cell proliferation, migration, invasion and tube formation, were substantially inhibited by HM-3-HSA. Mechanism investigations revealed that HM-3-HSA could bind HUVECs via integrin αvβ3 and α5β1 and inhibited phosphorylation of the downstream protein kinases including FAK, Src and PI3 K. Our study was the first to report the activity of HM-3-HSA against hepatocellular carcinoma and tumor angiogenesis as well as the underlying mechanism by which HM-3-HSA to exert its anti-angiogenic activity.

A DNA Aptamer Targeting Galectin-1 as a Novel Immunotherapeutic Strategy for Lung Cancer

Galectin-1 (Gal-1) is a pleiotropic homodimeric β-galactoside-binding protein with a single carbohydrate recognition domain. It has been implicated in several biological processes that are important during tumor progression. Several lines of evidence have indicated that Gal-1 is involved in cancer immune escape and induces T cell apoptosis. These observations all emphasized Gal-1 as a novel target for cancer immunotherapy. Here, we developed a novel Gal-1-targeting DNA aptamer (AP-74 M-545) and demonstrated its antitumor effect by restoring immune function. AP-74 M-545 binds to Gal-1 with high affinity. AP-74 M-545 targets tumors in murine tumor models but suppresses tumor growth only in immunocompetent C57BL/6 mice, not in immunocompromised non-obese diabetic (NOD)/severe combined immunodeficiency (SCID) mice. Immunohistochemistry revealed increased CD4⁺ and CD8⁺ T cells in AP-74 M-545-treated tumor tissues. AP-74 M-545 suppresses T cell apoptosis by blocking the binding of Gal-1 to CD45, the main receptor and apoptosis mediator of Gal-1 on T cells. Collectively, our data suggest that the Gal-1 aptamer suppresses tumor growth by blocking the interaction between Gal-1 and CD45 to rescue T cells from apoptosis and restores T cell-mediated immunity. These results indicate that AP-74 M-545 may be a potential strategy for cancer immunotherapy.

Glycosylation in health and disease

The glycome describes the complete repertoire of glycoconjugates composed of carbohydrate chains, or glycans, that are covalently linked to lipid or protein molecules. Glycoconjugates are formed through a process called glycosylation and can differ in their glycan sequences, the connections between them and their length. Glycoconjugate synthesis is a dynamic process that depends on the local milieu of enzymes, sugar precursors and organelle structures as well as the cell types involved and cellular signals. Studies of rare genetic disorders that affect glycosylation first highlighted the biological importance of the glycome, and technological advances have improved our understanding of its heterogeneity and complexity. Researchers can now routinely assess how the secreted and cell-surface glycomes reflect overall cellular status in health and disease. In fact, changes in glycosylation can modulate inflammatory responses, enable viral immune escape, promote cancer cell metastasis or regulate apoptosis; the composition of the glycome also affects kidney function in health and disease. New insights into the structure and function of the glycome can now be applied to therapy development and could improve our ability to fine-tune immunological responses and inflammation, optimize the performance of therapeutic antibodies and boost immune responses to cancer. These examples illustrate the potential of the emerging field of 'glycomedicine'.

Combination of anginex gene therapy and radiation decelerates the growth and pulmonary metastasis of human osteosarcoma xenografts

Investigate whether rAAV-anginex gene therapy combined with radiotherapy could decrease growth and pulmonary metastasis of osteosarcoma in mice and examine the mechanisms involved in this therapeutic strategy. During in vitro experiment, multiple treatment regimes (rAAV-eGFP, radiotherapy, rAAV-anginex, combination therapy) were applied to determine effects on proliferation of endothelial cells (ECs) and G-292 osteosarcoma cells. During in vivo analysis, the same multiple treatment regimes were applied to osteosarcoma tumor-bearing mice. Use microcomputed tomography to evaluate tumor size. Eight weeks after tumor cell inoculation, immunohistochemistry was used to assess the therapeutic efficacy according to microvessel density (MVD), proliferating cell nuclear antigen (PCNA), and terminal-deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) assays. Metastasis of lungs was also evaluated by measuring number of metastatic nodules and wet weight of metastases. The proliferation of ECs and the tumor volumes in combination therapy group were inhibited more effectively than the other three groups at end point (P < 0.05). Cell clone assay showed anginex had radiosensitization effect on ECs. Immunohistochemistry showed tumors from mice treated with combination therapy exhibited the lowest MVD and proliferation rate, with highest apoptosis rate, as confirmed by IHC staining for CD34 and PCNA and TUNEL assays (P < 0.05). Combination therapy also induced the fewest metastatic nodules and lowest wet weights of the lungs (P < 0.05). rAAV-anginex combined with radiotherapy induced apoptosis of osteosarcoma cells and inhibited tumor growth and pulmonary metastasis on the experimental osteosarcoma models. We conclude that the primary mechanism of this process may be due to sensitizing effect of anginex to radiotherapy.

Antiangiogenic effects of AA-PMe on HUVECs in vitro and zebrafish in vivo

Angiogenesis plays a vital role in many physiological and pathological processes and several diseases are connected with its dysregulation. Asiatic acid (AA) has demonstrated anticancer properties and we suspect this might be attributable to an effect on angio-genesis. A modified derivative of AA, N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-L-proline methyl ester (AA-PMe), has improved efficacy over its parent compound, but its effect on blood vessel development remains unclear.

Methods

In this study, we investigated the antiangiogenic activity of AA and AA-PMe in zebrafish embryos and human umbilical vein endothelial cells (HUVECs). First of all, we treated HUVECs with increasing concentrations of AA-PMe or AA, with or without vascular endothelial growth factor (VEGF) present, and assessed cell viability, tube formation, and cell migration and invasion. Quantitative real-time polymerase chain reaction and Western blot analysis were later used to determine the role of vascular endothelial growth factor receptor 2 (VEGFR2)-mediated signaling in AA-PMe inhibition of angiogenesis. We extended these studies to follow angiogenesis using Tg(fli:EGFP) transgenic zebrafish embryos. For these experiments, embryos were treated with varying concentrations of AA-PMe or AA from 24 to 72 hours postfertilization prior to morphological observation, angiogenesis assessment, and endogenous alkaline phosphatase assay. VEGFR2 expression in whole embryos following AA-PMe treatment was also determined.

Results

We found AA-PMe decreased cell viability and inhibited migration and tube formation in a dose-dependent manner in HUVECs. Similarly, AA-PMe disrupted the formation of intersegmental vessels, the dorsal aorta, and the posterior cardinal vein in zebrafish embryos. Both in vitro and in vivo AA-PMe surpassed AA in its ability to block angiogenesis by suppressing VEGF-induced phosphorylation of VEGFR2 and disrupting downstream extracellular regulated protein kinase and AKT signaling.

Conclusion

For the first time, this study reveals that AA-PMe acts as a potent VEGFR2 kinase inhibitor and exerts powerful antiangiogenic activity, suggesting it to be a promising therapeutic candidate for further research.

Galectin Targeted Therapy in Oncology: Current Knowledge and Perspectives

The incidence and mortality of cancer have increased over the past decades. Significant progress has been made in understanding the underpinnings of this disease and developing therapies. Despite this, cancer still remains a major therapeutic challenge. Current therapeutic research has targeted several aspects of the disease such as cancer development, growth, angiogenesis and metastases. Many molecular and cellular mechanisms remain unknown and current therapies have so far failed to meet their intended potential. Recent studies show that glycans, especially oligosaccharide chains, may play a role in carcinogenesis as recognition patterns for galectins. Galectins are members of the lectin family, which show high affinity for β-galactosides. The galectin–glycan conjugate plays a fundamental role in metastasis, angiogenesis, tumor immunity, proliferation and apoptosis. Galectins’ action is mediated by a structure containing at least one carbohydrate recognition domain (CRD). The potential prognostic value of galectins has been described in several neoplasms and helps clinicians predict disease outcome and determine therapeutic interventions. Currently, new therapeutic strategies involve the use of inhibitors such as competitive carbohydrates, small non-carbohydrate binding molecules and antibodies. This review outlines our current knowledge regarding the mechanism of action and potential therapy implications of galectins in cancer.

Coptis japonica Makino extract suppresses angiogenesis through regulation of cell cycle-related proteins

Angiogenesis, neovascularization from pre-existing vessels, is a key step in tumor growth and metastasis, and anti-angiogenic agents that can interfere with these essential steps of cancer development are a promising strategy for human cancer treatment. In this study, we characterized the anti-angiogenic effects of Coptis japonica Makino extract (CJME) and its mechanism of action. CJME significantly inhibited the proliferation, migration, and invasion of vascular endothelial growth factor (VEGF)-stimulated HUVECs. Furthermore, CJME suppressed VEGF-induced tube formation in vitro and VEGF-induced microvessel sprouting ex vivo. According to our study, CJME blocked VEGF-induced cell cycle transition in G1. CJME decreased expression of cell cycle-regulated proteins, including Cyclin D, Cyclin E, Cdk2, and Cdk4 in response to VEGF. Taken together, the results of our study indicate that CJME suppresses VEGF-induced angiogenic events such as proliferation, migration, and tube formation via cell cycle arrest in G1.

Recombinant adeno-associated virus-delivered anginex inhibits angiogenesis and growth of HUVECs by regulating the Akt, JNK and NF-κB signaling pathways

Anginex is an artificial synthetic small molecule β-sheet-forming peptide shown to have anti-angiogenesis and antitumor effects in various solid tumors. However, its molecular mechanism remains largely unclear and efficient delivery methods for anginex remains to be developed. We report on the development of recombinant adeno-associated virus (rAAV2)-delivered anginex and the underlying mechanism of anti-angiogenesis and antitumor effects of anginex. We have successfully developed the rAAV2 vector to efficiently express anginex (rAAV2‑anginex). Transduction of rAAV2-anginex significantly induced apoptosis, and inhibited the proliferation, migration, invasion and tube formation of human umbilical vein endothelial cells in vitro. Western blot analysis revealed that rAAV2‑anginex inhibited the phosphorylation of Akt, while inducing the phosphorylation of JNK and activation of the NF-κB signaling pathway. In an in vivo CAM assay and xenograft model of SKOV3, rAAV2-anginex significantly reduced microvessel density (MVD) and vascular endothelial growth factor 165 (VEGF165), as demonstrated by immunohistochemistry analysis. Importantly, rAAV2-anginex inhibited tumor growth in an ovarian cancer SKOV3 cell nude mouse xenograft model. Our results suggest that rAAV2-anginex may inhibit tumor angiogenesis and growth through regulating Akt, JNK and NF-κB signaling pathways.

Inhibitors of Galectins and Implications for Structure-Based Design of Galectin-Specific Therapeutics

Galectins are a family of galactoside-specific lectins that are involved in a myriad of metabolic and disease processes. Due to roles in cancer and inflammatory and heart diseases, galectins are attractive targets for drug development. Over the last two decades, various strategies have been used to inhibit galectins, including polysaccharide-based therapeutics, multivalent display of saccharides, peptides, peptidomimetics, and saccharide-modifications. Primarily due to galectin carbohydrate binding sites having high sequence identities, the design and development of selective inhibitors targeting particular galectins, thereby addressing specific disease states, is challenging. Furthermore, the use of different inhibition assays by research groups has hindered systematic assessment of the relative selectivity and affinity of inhibitors. This review summarises the status of current inhibitors, strategies, and novel scaffolds that exploit subtle differences in galectin structures that, in conjunction with increasing available data on multiple galectins, is enabling the feasible design of effective and specific inhibitors of galectins.

Advances and prospects of anginex as a promising anti-angiogenesis and anti-tumor agent

Anginex, a novel artificial cytokine-like peptide (βpep-25), is designed by using basic folding principles and incorporating short sequences from the β-sheet domains of anti-angiogenic agents, including platelet factor-4 (PF4), interleukin-8 (IL-8), and bactericidal-permeability increasing protein 1 (BP1). Anginex can specially block the adhesion and migration of the angiogenically activated endothelial cells (ECs), leading to apoptosis and ultimately to the inhibition of angiogenesis and tumor growth. In vitro and in vivo studies have proved its inhibitory effects on the formation of new blood vessels and tumor growth even though the mechanism is not clear. The inhibitory effects of anginex can be enhanced when it is applied in combination with other therapies, such as chemotherapy, radiotherapy and other anti-angiogenic agents. The limitations of anginex, including poor stability, short half life, complicated synthesis and low purity, have been conquered by modifying its structure or designing novel compound anginex and recombinant anginex, which makes possible the clinical application of anginex. Here, we summarize the basic and preclinical trials of anginex and discuss the prospects of anginex in clinical application. We come to the conclusion that anginex and compound or recombinant anginex can be used as effective anti-angiogenic agents.

Quercetin-4'-O-β-D-glucopyranoside (QODG) inhibits angiogenesis by suppressing VEGFR2-mediated signaling in zebrafish and endothelial cells

BACKGROUND

Angiogenesis plays an important role in many physiological and pathological processes. Identification of small molecules that block angiogenesis and are safe and affordable has been a challenge in drug development. Hypericum attenuatum Choisy is a Chinese herb medicine commonly used for treating hemorrhagic diseases. The present study investigates the anti-angiogenic effects of quercetin-4'-O-β-D-glucopyranoside (QODG), a flavonoid isolated from Hypericum attenuatum Choisy, in vivo and in vitro, and clarifies the underlying mechanism of the activity.

METHODOLOGY/PRINCIPAL FINDINGS

Tg(fli1:EGFP) transgenic zebrafish embryos were treated with different concentrations of quercetin-4'-O-β-D-glucopyranoside (QODG) (20, 60, 180 µM) from 6 hours post fertilisation (hpf) to 72 hpf, and adult zebrafish were allowed to recover in different concentrations of QODG (20, 60, 180 µM) for 7 days post amputation (dpa) prior morphological observation and angiogenesis phenotypes assessment. Human umbilical vein endothelial cells (HUVECs) were treated with or without VEGF and different concentrations of QODG (5, 20, 60, 180 µM), then tested for cell viability, cell migration, tube formation and apoptosis. The role of VEGFR2-mediated signaling pathway in QODG-inhibited angiogenesis was evaluated using quantitative real-time PCR (qRT-PCR) and Western blotting.

CONCLUSION/SIGNIFICANCE

Quercetin-4'-O-β-D-glucopyranoside (QODG) was shown to inhibit angiogenesis in human umbilical vein endothelial cells (HUVECs) in vitro and zebrafish in vivo via suppressing VEGF-induced phosphorylation of VEGFR2. Our results further indicate that QODG inhibits angiogenesis via inhibition of VEGFR2-mediated signaling with the involvement of some key kinases such as c-Src, FAK, ERK, AKT, mTOR and S6K and induction of apoptosis. Together, this study reveals, for the first time, that QODG acts as a potent VEGFR2 kinase inhibitor, and exerts the anti-angiogenic activity at least in part through VEGFR2-mediated signaling pathway.

5-Formylhonokiol exerts anti-angiogenesis activity via inactivating the ERK signaling pathway

Our previous report has demonstrated that 5-formylhonokiol (FH), a derivative of honokiol (HK), exerts more potent anti-proliferative activities than honokiol in several tumor cell lines. In present study, we first explored the antiangiogenic activities of 5-formylhonokiol on proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs) for the first time in vitro. Then we investigated the in vivo antiangiogenic effect of 5-formylhonokiol on zebrafish angiogenesis model. In order to clarify the underlying molecular mechanism of 5-formylhonokiol, we investigated the signaling pathway involved in controlling the angiogenesis process by western blotting assay. Wound-healing results showed that 5-formylhonokiol significantly and dose-dependently inhibited migration of cultured human umbilical vein enthothelial cells. The invasiveness of HUVEC cells was also effectively suppressed at a low concentration of 5-formylhonokiol in the transwell assay. Further F-actin imaging revealed that inhibitory effect of 5-formylhonokiol on invasion may partly contribute to the disruption of assembling stress fiber. Tube formation assay, which is associated with endothelial cells migration, further confirmed the anti-angiogenesis effect of 5-formylhonokiol. In in vivo zebrafish angiogenesis model, we found that 5-formylhonokiol dose-dependently inhibited angiogenesis. Furthermore, western blotting showed that 5-formylhonokiol significantly down-regulated extracellular signal-regulated kinase (ERK) expression and inhibited the phosphorylation of ERK but not affecting the total protein kinase B (Akt) expression and related phosphorylation, suggesting that 5-formylhonokiol might exert anti-angiogenesis capacity via down-regulation of the ERK signal pathway. Taken together, these data suggested that 5-formylhonokiol might be a viable drug candidate in antiangiogenesis and anticancer therapies.

Efficient delivery of payload into tumor cells in a controlled manner by TAT and thiolytic cleavable PEG co-modified liposomes

Recently, PEGylation has been extensively employed to increase the circulation time of liposomes and enhance their accumulation in tumor tissue via the enhanced permeability and retention (EPR) effect; however, poly(ethylene glycol) (PEG) is unfavorable for the uptake of liposomes by tumor cells because of its steric hindrance. In this study, thiolytic cleavable PEG modified liposomes were used to solve this dilemma. Before arrival at the tumor tissue, PEG presents on the surface of liposomes, which is useful for passive accumulation in tumor tissue. Upon reaching the tumor tissues, the PEG chain could be removed by a safe cleaving reagent l-cysteine (l-Cys), and thus, the steric hindrance of PEG could be overcome conveniently. To further improve the uptake of liposomes, a "functional molecule" cell-penetrating peptide TAT was attached to the distal end of a shorter PEG spacer anchored to the surface of the liposomes, which could be shielded by cleavable PEG during circulation; upon arriving at tumor tissue, PEG was removed and thus the "functional molecule" TAT was exposed, and then TAT could mediate the uptake of the liposomes with high efficiency. In this study, thiolytic cleavable PEG was synthesized via a disulfide bridge, DOPE-PEG(1600)-TAT was synthesized by sulfhydryl-maleimide reaction, and then Rh-PE labeled liposomes composed of 2% DOPE-PEG(1600)-TAT and various amounts of cleavable PEG(5000) (2%, 4%, and 8%) were prepared, with particle size around 100 nm and slightly negative charge. These liposomes showed good stability in the presence of 10% serum. Their uptake by tumor cells HepG2 in vitro was assessed qualitatively and quantitatively. Liposomes modified with 2% DOPE-PEG(1600)-TAT and 8% DOPE-S-S-mPEG(5000) were regarded as the optimal formulation. In this preparation, nearly no uptake could be observed before addition of l-Cys, which meant undesired uptake during circulation could be avoided, while the uptake upon addition of l-Cys was 4 times as high as that in the absence of l-Cys. For the uptake in vivo, calcein loaded and Rh-PE labeled 8% cleavable PEG + 2% TAT modified liposomes were injected intratumorally into H22 tumor bearing mice. Confocal laser scanning microscopy (CLSM) showed that the uptake of 8% cleavable PEG + 2% TAT modified liposomes was much higher than that of 8% noncleavable PEG + 2% TAT modified liposomes in the presence of l-Cys. Thus, tumor targeted delivery could be achieved efficiently by the liposomal drug delivery system developed here in a controlled manner.