Antiangiogenic effect of bile acid acylated heparin derivative

Nanoarchitectured conjugates targeting angiogenesis: investigating heparin-taurocholate acid conjugates (LHT7) as an advanced anti-angiogenic therapy for brain tumor treatment

BACKGROUND

Glioblastoma is a highly malignant brain tumor associated with poor prognosis. Conventional therapeutic approaches have limitations due to their toxic effects on normal tissue and the development of tumor cell resistance. This study aimed to explore alternative mechanisms for glioblastoma treatment by targeting angiogenesis.

METHODS

The study investigated the anti-angiogenic properties of heparin in glioblastoma treatment. To overcome the limitations of heparin, a heparin-taurocholate conjugate (LHT7) was synthesized by conjugating heparin to taurocholic acid. The study utilized the U87MG human glioblastoma cell line and human umbilical vein endothelial cells (HUVEC) as experimental models. Cell viability assays and sprouting assays were performed to assess the effects of LHT7. Additionally, phosphorylation of angiogenesis-related proteins, such as phospho-ERK and phospho-VEGFR2, was measured. The anti-angiogenic effects of LHT7 were further evaluated using a glioblastoma orthotopic mouse model.

RESULTS

Treatment with LHT7 resulted in a dose-dependent reduction in cell viability in U87MG human glioblastoma cells. The sprouting of HUVEC cells was significantly decreased upon LHT7 treatment. Furthermore, LHT7 treatment led to a decrease in the phosphorylation of angiogenesis-related proteins, including phospho-ERK and phospho-VEGFR2. In the glioblastoma orthotopic mouse model, LHT7 exhibited anti-angiogenic effects, supporting its potential as a therapeutic agent.

CONCLUSIONS

The conjugation of heparin and taurocholic acid to create LHT7 offers several advantages over conventional therapeutic approaches for glioblastoma. LHT7 demonstrated anti-angiogenic properties, as evidenced by the reduction in cell viability and inhibition of endothelial cell sprouting. Moreover, LHT7 modulated the phosphorylation of angiogenesis-related proteins. These findings suggest that LHT7 holds promise as a medication for glioblastoma treatment, offering potential implications for improving patient outcomes.

Bile Acids: Physiological Activity and Perspectives of Using in Clinical and Laboratory Diagnostics

Bile acids play a significant role in the digestion of nutrients. In addition, bile acids perform a signaling function through their blood-circulating fraction. They regulate the activity of nuclear and membrane receptors, located in many tissues. The gut microbiota is an important factor influencing the effects of bile acids via enzymatic modification. Depending on the rate of healthy and pathogenic microbiota, a number of bile acids may support lipid and glucose homeostasis as well as shift to more toxic compounds participating in many pathological conditions. Thus, bile acids can be possible biomarkers of human pathology. However, the chemical structure of bile acids is similar and their analysis requires sensitive and specific methods of analysis. In this review, we provide information on the chemical structure and the biosynthesis of bile acids, their regulation, and their physiological role. In addition, the review describes the involvement of bile acids in various diseases of the digestive system, the approaches and challenges in the analysis of bile acids, and the prospects of their use in omics technologies.

Research Progress of Bile Acids in Cancer

Bile acids (BAs) were originally known as detergents to facilitate the digestion and absorption of lipids. And our current knowledge of BAs has been extended to potential carcinogenic or cancer suppressor factors due to constant research. In fact, BAs were regarded as a tumor promoters as early as the 1940s. Differential bile acid signals emitted by various bile acid profiles can produce distinct pathophysiological traits, thereby participating in the occurrence and development of tumors. Nevertheless, in recent years, more and more studies have noticed the value of BAs as therapeutic targets. And several studies have applied BAs as a therapeutic agent for various diseases including cancer. Based on the above evidence, we acknowledge that the role of BAs in cancer has yet to be exploited, although considerable efforts have been made to probe the functions of BAs. In this review, we describe the characteristics of BAs as a double-edged sword in cancer, hoping to provide references for future cancer treatments.

Physiology and Physical Chemistry of Bile Acids

Bile acids (BAs) are facial amphiphiles synthesized in the body of all vertebrates. They undergo the enterohepatic circulation: they are produced in the liver, stored in the gallbladder, released in the intestine, taken into the bloodstream and lastly re-absorbed in the liver. During this pathway, BAs are modified in their molecular structure by the action of enzymes and bacteria. Such transformations allow them to acquire the chemical-physical properties needed for fulling several activities including metabolic regulation, antimicrobial functions and solubilization of lipids in digestion. The versatility of BAs in the physiological functions has inspired their use in many bio-applications, making them important tools for active molecule delivery, metabolic disease treatments and emulsification processes in food and drug industries. Moreover, moving over the borders of the biological field, BAs have been largely investigated as building blocks for the construction of supramolecular aggregates having peculiar structural, mechanical, chemical and optical properties. The review starts with a biological analysis of the BAs functions before progressively switching to a general overview of BAs in pharmacology and medicine applications. Lastly the focus moves to the BAs use in material science.

Molecular Targeting of VEGF with a Suramin Fragment-DOCA Conjugate by Mimicking the Action of Low Molecular Weight Heparins

Molecular targeting of growth factors has shown great therapeutic potential in pharmaceutical research due to their roles in pathological conditions. In the present study, we developed a novel suramin fragment and deoxycholic acid conjugate (SFD) that exhibited the potential to bind to the heparin-binding site (HBD) of vascular endothelial growth factor (VEGF) and to inhibit its pathogenic action for the first time. Notably, SFD was optimally designed for binding to the HBD of VEGF using the naphthalenetrisulfonate group, allowing to observe its excellent binding efficacy in a surface plasmon resonance (SPR) study, showing remarkable binding affinity (K_D = 3.8 nM) as a small molecule inhibitor. In the tubular formation assay, it was observed that SFD could bind to HBD and exhibit antiangiogenic efficacy by inhibiting VEGF, such as heparins. The cellular treatment of SFD resulted in VEGF-inhibitory effects in human umbilical vein endothelial cells (HUVECs). Therefore, we propose that SFD can be employed as a novel drug candidate to inhibit the pathophysiological action of VEGF in diseases. Consequently, SFD, which has a molecular structure optimized for binding to HBD, is put forward as a new chemical VEGF inhibitor.

LMWH and its derivatives represent new rational for cancer therapy: construction strategies and combination therapy

Low-molecular-weight heparin (LMWH) has attracted increasing attention as a tumor treatment because of its board range of physiological functions. Over the past decade, diverse LMWH derivatives have increased the variety of antitumor strategies available, serving not only as anti-tumor agents, but also as drug delivery platforms. In this review, we introduce the basic strategy for structural modification of LMWH to attenuate its antitumor activity while reducing its risk of bleeding and immune responses, as well as highlighting current applications of LMWH and its derivatives in cancer therapy. We select representative drug delivery systems involving LMWH derivatives and discuss the construction principles and therapeutic effects associated with their use. We also analyze progress made in the development of antitumor combination therapies, in which LMWH has shown synergistic or combined effects with other treatment strategies.

Anti-angiogenic activity and antitumor efficacy of amphiphilic twin drug from ursolic acid and low molecular weight heparin

Heparin, a potential blood anti-coagulant, is also known for its binding ability to several angiogenic factors through electrostatic interactions due to its polyanionic character. However, the clinical application of heparin for cancer treatment is limited by several drawbacks, such as unsatisfactory therapeutic effects and severe anticoagulant activity that could induce hemorrhaging. Herein, low molecular weight heparin (LMWH) was conjugated to ursolic acid (UA), which is also an angiogenesis inhibitor, by binding the amine group of aminoethyl-UA (UA-NH2) with the carboxylic groups of LMWH. The resulting LMWH-UA conjugate as an amphiphilic twin drug showed reduced anticoagulant activity and could also self-assemble into nanomicelles with a mean particle size ranging from 200-250 nm. An in vitro endothelial tubular formation assay and an in vivo Matrigel plug assay were performed to verify the anti-angiogenic potential of LMWH-UA. Meanwhile, the in vivo antitumor effect of LMWH-UA was also evaluated using a B16F10 mouse melanoma model. LMWH-UA nanomicelles were shown to inhibit angiogenesis both in vitro and in vivo. In addition, the i.v. administration of LMWH-UA to the B16F10 tumor-bearing mice resulted in a significant inhibition of tumor growth as compared to the free drug solutions. These findings demonstrate the therapeutic potential of LMWH-UA as a new therapeutic remedy for cancer therapy.

Comparison of Topical Low-Molecular-Weight Heparin-Taurocholate and Bevacizumab for Treatment and Prevention of Corneal Neovascularization

PURPOSE

To compare the therapeutic and preventive effects of topically administered 7-taurocholic acid-conjugated low-molecular-weight heparin (LHT7) and bevacizumab in experimentally induced corneal neovascularization (CoNV).

METHODS

CoNV was induced using sutures in the right eyes of 24 mice. To investigate the therapeutic effects, CoNV was allowed to develop for 1 week before treatment. To ascertain the preventive effects, the treatments were applied immediately after the suture. In each experiment, 12 eyes were divided into 3 groups and treated topically using bevacizumab (bevacizumab group), LHT7 (LHT7 group), and normal saline (control group). The treatments were instilled 3 times daily for 2 weeks. The CoNV area was measured before instillation and after 1 and 2 weeks after instillation.

RESULTS

In the investigation of therapeutic effects, the CoNV area had decreased significantly 1 week after treatment in the bevacizumab group (1.58-0.75 mm; P = 0.036) and LHT7 group (1.38-0.74 mm; P = 0.018). Two weeks after treatment, the CoNV area was significantly smaller in the bevacizumab groups (0.60 mm; P = 0.005) and LHT7 group (0.64 mm; P = 0.015) than in the control group (1.68 mm), but the bevacizumab group did not differ significantly from the LHT7 group. In the experiment addressing the preventive effects, CoNV was less developed in the bevacizumab group (0.70 mm; P = 0.003) and LHT7 group (0.54 mm; P = 0.003) than in the control group (1.75 mm), and the CoNV area was smaller in the LHT7 group than in the bevacizumab group (P = 0.021).

CONCLUSIONS

The effects of LHT7 on CoNV regression are comparable to those of bevacizumab. Topical administration of LHT7 prevents CoNV more effectively than bevacizumab.

End-Site-Specific Conjugation of Enoxaparin and Tetradeoxycholic Acid Using Nonenzymatic Glycosylation for Oral Delivery

Heparin and low molecular weight heparins (LMWHs) have been the drug of choice for the treatment or the prevention of thromboembolic disease. Different methods are employed to prepare the LMWHs that are clinically approved for the market currently. In particular, enoxaparin, which has a reducing sugar moiety at the end-site of polysaccharide, is prepared by alkaline depolymerization. Focusing on this end-site-specific activity of LMWHs, we conjugated the tetraoligomer of deoxycholic acid (TetraDOCA; TD) at the end-site of enoxaparin via nonenzymatic glycosylation reaction. The end-site-specific conjugation is important for polysaccharide drug development because of the heterogeneity of polysaccharides. This study also showed that orally active enoxaparin and tetraDOCA conjugate (EnoxaTD) had therapeutic effect on deep vein thrombosis (DVT) without bleeding in animal models. Considering the importance of end-specific conjugation, these results suggest that EnoxaTD could be a drug candidate for oral heparin development.

Self-assembling lipid modified glycol-split heparin nanoparticles suppress lipopolysaccharide-induced inflammation through TLR4-NF-κB signaling

Self-assembling heparin nanoparticles have attracted much attention as promising drug carriers for various drugs, genes and imaging agents. In the present investigation, we found that heparin nanoparticles are selective Toll-like receptor 4 (TLR-4) antagonists and have a much greater anti-inflammatory effect than native heparin. More specifically, we developed self-assembling nanoparticles composed of glycol-split heparin/D-erythro-sphingosine conjugates (NAHNP), characterized their physicochemical properties and anti-inflammatory effect in vitro. Unlike native heparin, NAHNP significantly inhibited lipopolysaccharide-induced activation of MyD88-dependent NF-κB signaling pathway and production of pro-inflammatory cytokines such as TNF-alpha from mouse macrophages with IC50 = 0.019 mg/mL. Furthermore, we investigated the structure-activity relationship of the conjugates and identified the length of attached alkyl chains of d-erythro-sphingosine to be critical for anti-inflammatory effect. Decrease in alkyl chain length of NAHNP resulted in loss of inhibitory activity. In line with these findings, 6-O-sulfate groups of D-glucosamine residue were essential for effective inhibition, while removal of 2-O-sulfo and 3-O-sulfo groups as well as replacement of N-sulfo groups with N-acetyl did not alter anti-inflammatory activity. Therefore, NAHNP would be a promising candidate in acute and chronic inflammatory disorders, in addition to the nature of a drug carrier.

Subconjunctival injection of low-molecular-weight heparin-taurocholate 7 inhibits corneal neovascularization

PURPOSE

To evaluate the effects of a subconjunctival injection of low-molecular-weight heparin-taurocholate 7 (LHT7) on corneal neovascularization (CoNV) in rats.

METHODS

Twenty-four Sprague-Dawley rats were divided into 4 groups of 6 animals each. Corneal centers were cauterized by the application of a silver/potassium nitrate solution for 8 seconds. Either 0.02 or 0.04 mL of 25 mg/mL of LHT7 (low- and high-LHT7 groups, respectively) was subconjunctivally injected on days 2 and 4 after the cauterization was done; 0.02 mL of 25 mg/mL of bevacizumab was injected into rats in the positive control group, with normal saline (NS) being administered to a negative control group. Digital photographs of the cornea were taken 1 and 2 weeks later to calculate the percentage of CoNV using the area of the neovascularized cornea. To compare the differences in CoNV between weeks 1 and 2, the change in CoNV was calculated by subtracting the percentage of CoNV at 1 week from that at 2 weeks.

RESULTS

The percentage of CoNV did not differ among the 4 groups either 1 or 2 weeks after the cauterization (P > 0.05). In all groups except the NS group, the percentage of CoNV significantly decreased at 2 weeks compared with that at 1 week (all P < 0.05). Moreover, the changes of CoNV in the high-LHT7 and bevacizumab groups significantly decreased compared with that in the NS group (all P < 0.05). Two corneal stromal hemorrhages occurred, 1 in each LHT7 group.

CONCLUSIONS

Despite complications, including corneal stromal hemorrhage, subconjunctival injection of LHT7 attenuated CoNV after chemical cauterization.

Heparan sulfate mediates trastuzumab effect in breast cancer cells

Background

Trastuzumab is an antibody widely used in the treatment of breast cancer cases that test positive for the human epidermal growth factor receptor 2 (HER2). Many patients, however, become resistant to this antibody, whose resistance has become a major focus in breast cancer research. But despite this interest, there are still no reliable markers that can be used to identify resistant patients. A possible role of several extracellular matrix (ECM) components—heparan sulfate (HS), Syn-1(Syndecan-1) and heparanase (HPSE1)—in light of the influence of ECM alterations on the action of several compounds on the cells and cancer development, was therefore investigated in breast cancer cell resistance to trastuzumab.

Methods

The cDNA of the enzyme responsible for cleaving HS chains from proteoglycans, HPSE1, was cloned in the pEGFP-N1 plasmid and transfected into a breast cancer cell lineage. We evaluated cell viability after trastuzumab treatment using different breast cancer cell lines. Trastuzumab and HS interaction was investigated by confocal microscopy and Fluorescence Resonance Energy Transfer (FRET). The profile of sulfated glycosaminoglycans was also investigated by [³⁵S]-sulfate incorporation. Quantitative RT-PCR and immunofluorescence were used to evaluate HPSE1, HER2 and Syn-1 mRNA expression. HPSE1 enzymatic activity was performed using biotinylated heparan sulfate.

Results

Breast cancer cell lines responsive to trastuzumab present higher amounts of HER2, Syn-1 and HS on the cell surface, but lower levels of secreted HS. Trastuzumab and HS interaction was proven by FRET analysis. The addition of anti-HS to the cells or heparin to the culture medium induced resistance to trastuzumab in breast cancer cells previously sensitive to this monoclonal antibody. Breast cancer cells transfected with HPSE1 became resistant to trastuzumab, showing lower levels of HER2, Syn-1 and HS on the cell surface. In addition, HS shedding was increased significantly in these resistant cells.

Conclusion

Trastuzumab action is dependent on the availability of heparan sulfate on the surface of breast cancer cells. Furthermore, our data suggest that high levels of heparan sulfate shed to the medium are able to capture trastuzumab, blocking the antibody action mediated by HER2. In addition to HER2 levels, heparan sulfate synthesis and shedding determine breast cancer cell susceptibility to trastuzumab.

Multivalency of non-peptide integrin αVβ3 antagonist slows tumor growth

Multivalency is a powerful strategy for achieving high-affinity molecular binding of compounds to increase their therapeutic potency or imaging potential. In our study, multivalent non-peptide integrin αvβ3 antagonists (IA) were designed for antitumor therapy. Docking and molecular dynamics were employed to explore the binding modes of IA monomer, dimer, and trimer. In silico, one IA unit binds tightly in the active site with similar pose to native ligand RGD and other parts of dimer and trimer contribute extra binding affinities by interacting with residues in vicinity of the original site. In vitro studies demonstrated that increasing valency results in increasing antiproliferative and antiorganizational effects against endothelial cells (HUVECs), and a much weaker effect on melanoma B16F10 cells. The antitumor efficacies of the IA multivalent compounds were evaluated in subcutaneous B16F10 melanoma tumor-bearing mice. At 30 mg/kg dose, the mean masses of tumors harvested 18 days after inoculation were significantly reduced (p<10(-7)) by 36±9%, 49±8%, and 71±7% for the IA monomer, dimer, and trimer groups, relative to control. The importance of multivalency was demonstrated to be highly significant beyond the additive effect of the extra pharmacological sites (p=0.00011). These results suggest that the major target of these anti-αvβ3 compounds is the neovasculature rather than the cancer cells, and the success of a multivalent strategy depends on the details of the components and linker. This is the first integrin αvβ3 multivalent ligand showing clear enhancement in antitumor effectiveness.

Anticancer steroids: linking natural and semi-synthetic compounds

Steroids, a widespread class of natural organic compounds occurring in animals, plants and fungi, have shown great therapeutic value for a broad array of pathologies. The present overview is focused on the anticancer activity of steroids, which is very representative of a rich structural molecular diversity and ability to interact with various biological targets and pathways. This review encompasses the most relevant discoveries on steroid anticancer drugs and leads through the last decade and comprises 668 references.

Cyclic RGDyk-conjugated LMWH-taurocholate derivative as a targeting angiogenesis inhibitor

LMWH-taurocholate derivative (LHT7) has been reported as a novel angiogenesis inhibitor, due to its ability to bind to several kinds of growth factors, which play critical roles in tumor angiogenesis. In this study, we have highlighted the enhanced antiangiogenic activity of LHT7, by using cyclic RGDyk (cRGD), a targeting moiety that was chemically conjugated to LHT7 via amide bond. The SPR study revealed that cRGD-LHT7 bound to α(v)β(3) integrin as strongly as cRGD, and it bound to VEGF as strongly as LHT7. Importantly, in vitro anti-angiogenesis studies revealed that cRGD-LHT7 had a significant inhibition effect on HUVEC tubular formation. Finally, cRGD-LHT7 showed a greater inhibitory efficiency on the tumor growth in the U87MG xenograft model than the original LHT7, which was owed to its ability to target the tumor cells. All of these findings demonstrated that cRGD-LHT7 targeted α(v)β(3) integrin-positive cancer cells and endothelial cells, resulting in a greater anti-angiogenesis effect on the solid tumors.

Potentiation of anti-angiogenic activity of heparin by blocking the ATIII-interacting pentasaccharide unit and increasing net anionic charge

Heparin, a potent anticoagulant used for the prevention of venous thromboembolism, has been recognized as a tumor angiogenesis inhibitor. Its limitation in clinical application for cancer therapy, however, arises from its strong anticoagulant activity, which causes associated adverse effects. In this study, we show the structural correlation of LHT7, a previously developed heparin-based angiogenesis inhibitor, with its influence on VEGF blockade and its decreased anticoagulant activity. LHT7 was characterized as having average seven molecules of sodium taurocholates conjugated to one molecule of low-molecular-weight heparin (LMWH). This study showed that the conjugation of sodium taurocholates selectively blocked interaction with antithrombin III (ATIII) while enhancing the binding with VEGF. This resulted in LHT7 to have negligible anticoagulant activity but potent anti-angiogenic activity. Following up on this finding, we showed that the bidirectional effect of sodium taurocholate conjugation was due to its unique structure, that is, the sterane core hindering the ATIII-binding pentasaccharide unit of LMWH with its bulky and rigid structural characteristics while the terminal sulfate group interacts with VEGF to produce stronger binding. In addition, we showed that LHT7 was localized in the tumor, especially on the endothelial cells. One explanation for this might be that LHT7 was delivered to the tumor via platelets.

High antiangiogenic and low anticoagulant efficacy of orally active low molecular weight heparin derivatives

Heparin, an anticoagulant that is widely used clinically, is also known to bind to several kinds of proteins through electrostatic interactions because of its polyanionic character. These interactions are mediated by the physicochemical properties of heparin such as sequence composition, sulfation patterns, charge distribution, overall charge density, and molecular size. Although this electrostatic character mediates its binding to many proteins related with tumor progression, thereby providing its antiangiogenic property, the administration of heparin for treating cancer is limited in clinical applications due to several drawbacks, such as its low oral absorption, unsatisfactory therapeutic effects, and strong anticoagulant activity which induces hemorrhaging. Here, we evaluated novel, orally active, low molecular weight heparin (LMWH) derivatives (LHD) conjugated with deoxycholic acid (DOCA) that show reduced anticoagulant activity and enhanced antiangiogenic activity. The chemical conjugate of LMWH and DOCA was synthesized by conjugating the amine group of N-deoxycholylethylamine (EtDOCA) with the carboxylic groups of heparin at various DOCA conjugation ratios. The LMWH-DOCA conjugate series (LHD1, LHD1.5, LHD2, and LHD4) were further formulated with poloxamer 407 as a solubilizer for oral administration. An in vitro endothelial tubular formation and in vivo Matrigel plug assay were performed to verify the antiangiogenic potential of LHD. Finally, we evaluated tumor growth inhibition of oral LHD administration in a SCC7 model as well as in A549 human cancer cell lines in a mouse xenograft model. Increasing DOCA conjugation ratios showed decreased anticoagulant activity, eventually to zero. LHD could block angiogenesis in the tubular formation assay and the Matrigel plug assay. In particular, oral administration of LHD4, which has 4 molecules of DOCA per mole of LMWH, inhibited tumor growth in SCC7 mice model as well as A549 mice xenograft model. LHD4 was orally absorbable, showed minimal anticoagulant activity and inhibits tumor growth via antiangiogenesis. These findings demonstrate the therapeutic potential of LHD4 as a new oral anti-cancer drug.

Modest anti-cancer activity of a bile acid acylated heparin derivative in a PC14PE6 induced orthotopic lung cancer model

PURPOSE

A novel chemically modified heparin derivative, heparin-deoxycholic acid nano-particles, has lower anticoagulant activity, and was recently reported to have significant anti-tumor effects on squamous head and neck cancer cells. Therefore, the aim of this study was to evaluate the anti-tumor effects of heparin-deoxycholic acid nano-particles in a human lung adenocarcinoma cell line.

MATERIALS AND METHODS

An orthotopic lung cancer model in 16 mice was developed using intra-thoracic injections of 0.5x10(6) PC14PE6 cells. Ten days after inoculation, the mice were divided into two groups. PBS and Heparin-DOCA particles were injected once a day every 3 days in the tail vein, for a total of 5 injections. The body weight and survival of each mouse were monitored and the tumor size in the lung was measured by SPECT-CT before and after heparin-DOCA nano-particle treatment.

RESULTS

IThe HD particles had no significant cytotoxicity when the PC9 cells were treated in vitro. There was no statistical difference in tumor size, body weight and survival between the HD treated and control groups in vivo. Furthermore, there was no difference in the amount of CD31 between tumor tissues in the two study groups.

CONCLUSION

HD synthesized with unfractionated heparin had no apparent inhibitory effects on tumor growth in a PC14PE6 cell induced orthotopic lung cancer mouse model. The HD particles did not significantly inhibit tumor-induced angiogenesis at the tumor sites.

Des-gamma-carboxy prothrombin stimulates human vascular endothelial cell growth and migration

Des-gamma-carboxy prothrombin (DCP) is an aberrant prothrombin produced by hepatocellular carcinoma (HCC) cells. Serum and tissue DCP expressions are thought to reflect the biological malignant potential of HCC. However, the role of DCP in the development of angiogenesis is not well understood. Herein, we report the effects of DCP on growth and migration of human vascular endothelial cells. DCP significantly stimulated the proliferation of HUVEC (ECV304) cells in a dose and time dependent manner, as measured by the MTT assay. A continuous rapid migration of ECV304 cells was observed in the presence of DCP measured by the scratch wound assay. The continuous rapid invasive activity, measured by transwell chamber assay also showed that DCP increased endothelial cells migration through the reconstituted extracellular matrix (Matrigel). Further, the tube formation of vascular endothelial cells on 3-D Matrigel showed an increased number of branch points of ECV304 cells induced by DCP in a dose dependent manner. The levels of vascular endothelial cell growth-related angiogenic factors and matrix metalloproteinase were also examined. DCP significantly stimulated the expression levels of epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and matrix metalloproteinase (MMP)-2 (latent and active). Together, these data suggest that DCP is a novel type of vascular endothelial growth factor that possesses potent mitogenic and migrative activities in angiogenesis of HCC.

Following up tumour angiogenesis: from the basic laboratory to the clinic

Preceded by three decades of intense basic research on tumour angiogenesis, we are assisting to the translation of anti-antiangiogenic therapies as medical oncologists are increasingly using pioneering anti-angiogenic drugs in combination with standard treatments. While basic knowledge in the field of angiogenesis is reaching maturity and our level of understanding of the complex process of vessel development and growth in health and disease has been enriched at the molecular and cellular levels, the translation of this knowledge to the clinic is still in its infancy. Identifying the most suitable drugs, and the optimal dosage and schedule, as well as monitoring patients' responses to anti-angiogenic therapy, remain challenging issues that currently limit the benefit of this new therapeutic approach in cancer. This review will focus on a comprehensive description of the experimental assays in which angiogenesis research has been founded and how the different assays complement and provide relevant information for the task of characterising the angiogenic properties of diverse tumours, giving us a variety of tools to follow up tumour angiogenesis in research models. Following up tumour angiogenesis in patients and their response to antiangiogenic therapy is a more challenging task that will benefit in the near future from the use of non-invasive imaging methods as well as molecular and cellular biomarkers of angiogenesis suitable for clinical oncology. As both the design of the anti-angiogenic therapies and monitoring of the response are improved in the coming years to properly tailor them to the angiogenic profile of every patient, we hope to achieve increasing response and benefit of including antiangiogenic drugs as standard in cancer therapy.

Antimetastatic effect of an orally active heparin derivative on experimentally induced metastasis

PURPOSE

Orally active anticancer drugs have great advantages for the treatment of cancer. Compelling data suggest that heparin exhibits critical antimetastatic effects via interference with P-selectin-mediated cell-cell binding. However, heparin should be given parenterally because it is not orally absorbed. Here, we evaluated the inhibitory effect of orally absorbable heparin derivative (LHD) on experimentally induced metastasis.

EXPERIMENTAL DESIGN

We developed LHD, which is a chemical conjugate of low molecular weight heparin and deoxycholic acid, and measured the plasma concentration of LHD after oral administration. To evaluate the antimetastatic effect of LHD, we carried out experimental lung metastasis assays in vivo using murine melanoma or human lung carcinoma cells and interruption assay between murine melanoma cells and activated platelets and human umbilical vascular endothelial cells in vitro.

RESULTS

In mice, the plasma concentration was approximately 7 microg/mL at 20 minutes after oral administration of LHD (10 mg/kg), indicating that bleeding was not induced at this dose. Interestingly, we found that LHD dramatically attenuated metastasis experimentally induced by murine melanoma or human lung carcinoma cells and that its antimetastatic activity was attributed to the interruption of the interactions between melanoma cells and activated platelets and between melanoma cells and human umbilical vascular endothelial cells by blocking selectin-mediated interactions. Furthermore, it prevented tumor growth in secondary organs.

CONCLUSIONS

On the basis of these findings, the present study shows the possibility of LHD as a suitable first-line anticancer drug that can be used for preventing metastasis and recurrence because it has therapeutic potential as an antimetastatic drug, has lower side effects, and can be orally absorbed.

Glucosylated heparin derivatives as non-toxic anti-cancer drugs

Heparin, which has been widely used as an anti-coagulant agent, has potential anti-tumor effects; in particular, low molecular weight heparin (LMWH) may inhibit tumor angiogenesis and/or metastasis with reduced toxicity. For decades, it has been known that malignant cancer cells display abnormally enhanced glucose uptake rates and overexpress glucose transporters (GLUTs) compared to normal cells. With these findings in mind, we introduced a glucose moiety to heparin for the purpose of increasing the concentration of heparin at the tumor site by targeting GLUTs. Three glucosylated heparin (GH) derivatives were prepared by conjugation of glucosamine and heparin in different mole ratios. To evaluate the potential of GH derivatives as anti-cancer drugs, their anti-coagulant activities, inhibitory effects on glucose analog uptake, cellular interactions, tumor growth inhibitory effects and sub-acute toxicities were investigated. The anti-coagulant activities of GH derivatives decreased proportionally to the degree of glucosylation. In vitro, GH derivatives inhibited HUVEC proliferation to a greater extent than heparin. GH derivatives mainly existed outside of cells and interacted with GLUTs on the cell surface, thereby inhibiting glucose uptake into cells. In vivo, GH derivatives significantly suppressed tumor growth compared to control, without systemic toxicity. Therefore, GH derivatives are proposed as potent non-toxic anti-cancer drugs.

Combination Therapy of Heparin–Deoxycholic Acid Conjugate and Doxorubicin against Squamous Cell Carcinoma and B16F10 Melanoma

PURPOSE

Our previous study confirmed that heparin-deoxycholic acid conjugate (HD) had a potent antiangiogenic effect and safety to use for long-term treatment. Herein, the combined therapeutic effect of HD and doxorubicin (DOX) was evaluated against squamous cell carcinoma (SCC7) and B16F10 melanoma.

METHODS

The inhibitory effect of cell proliferation and cellular uptake of HD was studied in SCC7 and B16F10. The combination effects of HD and DOX were evaluated by measuring cytotoxicity and apoptosis as well as tumor growth and apoptosis in vivo against SCC7 and B16F10 tumor-bearing mice.

RESULTS

HD displayed potent inhibitory effect on SCC7 and B16F10 cell proliferation, but it showed a low cytotoxic effect. Concurrent treatment of HD and DOX displayed enhanced cytotoxic effects and apoptosis on SCC7 and B16F10. The cellular uptake of HD and DOX was affected by the collective cytotoxic effects of these two drugs: each drug suppressed the tumor growth, and their combined treatment enhanced apoptosis and collectively inhibited the tumor growth of SCC7 and B16F10 in vivo.

CONCLUSION

These results demonstrated that HD with cytostatic and antiangiogenetic activities, enhanced the antitumor activity of DOX against SCC7 and B16F10, and the combined treatment of these two drugs might have enhanced therapeutic efficacy.

The attenuation of experimental lung metastasis by a bile acid acylated-heparin derivative

The inhibitory efficacies of new bile acid acylated-heparin derivative (heparin-DOCA) were evaluated on experimental lung metastasis. We evaluated the effect of heparin-DOCA on intercellular interactions including those between B16F10 and thrombin-activated platelets and TNF-alpha-activated HUVECs, and between B16F10 and immobilized mouse P-selectin. In addition, the inhibitory effects of heparin-DOCA on adhesion and invasion of B16F10 to Matrigel were studied. In an animal mouse study, the blood clot formation and the retention of red fluorescence protein (RFP)-B16F10 in lungs were assessed after heparin-DOCA and RFP-B16F10 intravenous administration. Furthermore, we investigated the anti-metastatic effect of heparin-DOCA against lung metastasis induced by B16F10 and SCC7. Heparin-DOCA inhibited intercellular interactions between B16F10 and activated platelets or activated HUVECs by blocking P- and E-selectin-mediated interactions. Moreover, it reduced adhesion and invasion of B16F10 to ECM, thereby affecting the reduction of early retention of B16F10 in the lung. Heparin-DOCA attenuated lung colony formation on the surfaces and in interior of the lung, and attenuated metastasis by B16F10 and SCC7. These results suggest that heparin-DOCA may have potentials as therapeutic agent that prevents tumor metastasis and progression.

Antiangiogenic and apoptotic properties of a novel amphiphilic folate-heparin-lithocholate derivative having cellular internality for cancer therapy

PURPOSE

Anitangiogenic and apoptotic properties of a novel chemically modified heparin derivative with low anticoagulant activity were evaluated on the experimental in vitro and in vivo model.

MATERIALS AND METHODS

Heparin-lithocholate conjugate (HL) was initially synthesized by covalently bonding lithocholate to heparin. Folate-HL conjugate (FHL) was further synthesized by conjugating folate to HL. Antiangiogenic and apoptotic abilities of HL and FHL were characterized in vitro and in vivo experimentations.

RESULTS

Compared to unmodified heparin, both HL and FHL represented a low anticoagulant activity (38 and 28%, respectively). HL and FHL maintained antiangiogenic activity even further modification from the results of Matrigel plugs assay. FHL specifically induced apoptosis on KB cells having highly expressed folate receptor after cellular internalization. Both administered HL and FHL had similar antiangiogenic activity and inhibitory effect on tumor growth in vivo although FHL induced higher apoptosis on tumor tissues.

CONCLUSIONS

In vivo tumor growth inhibition was possibly due to the decrease of vessel density and apoptotic cell death, although antiangiogenic effect of FHL seemed more actively affected on growth inhibition than apoptotic potential in vivo system. Thus, Low anticoagulant FHL having antiangiogenic and apoptotic properties would provide benefits for the development of a new class of anticancer agent.