Heparin as an anticancer therapeutic

The Tumorigenicity of Breast Cancer Cells Is Reduced upon Treatment with Small Extracellular Vesicles Isolated from Heparin Treated Cell Cultures

As a member of the HPSG family, heparin is often used as a specific probe of their role in cell physiology; indeed, we have previously shown a reduction in the tumorigenicity of breast cancer cells when cultured in its presence. However, a partial reversal of the anti-tumorigenic effect occurred when the treated cells were cultured in fresh medium without heparin, which led us to consider whether a more persistent effect could be achieved by treatment of the cells with small extracellular vesicles (sEV) from heparin-treated cells. The tumorigenicity was analyzed using sEV isolated from the culture medium of heparin-treated MCF-7 and MDA-MB231 breast cancer cells (sEV-HT) or from conditioned medium following the termination of treatment (heparin discontinued, sEV-HD). Tumorigenicity was reduced in cells cultured in the presence of sEV-HT compared to that of cells cultured in the presence of sEV from untreated cells (sEV-Ctrl). sEV-HD were also observed to exert an anti-tumorigenic effect on the expression of pro-tumorigenic and cell cycle regulatory proteins, as well as signaling activities when added to fresh cultures of MCF-7 and MDA-MB231 cells. The anti-tumorigenic activity of the heparin-derived sEV may arise from observed changes in the miRNA content or from heparin, which was observed to be bound to the sEV. sEV may constitute a relatively stable reservoir of circulating heparin, allowing heparin activity to persist in the circulation even after therapy has been discontinued. These findings can be considered as a special additional pharmacological characteristic of heparin clinical therapy.

Heparin Biofunctionalized Selenium Nanoparticles as Potential Antiangiogenic-Chemotherapeutic Agents for Targeted Doxorubicin Delivery

Combining antiangiogenic and chemotherapeutic agents has shown promising clinical benefits in cancer cures when the therapeutic intervention takes into account the tissue and molecular targets. Moreover, the risk of induced drug resistance is minimized when multiple pathways are involved in the treatment regimen, yielding a better therapeutic outcome. Nanodrug delivery systems have proven to be a prudent approach to treating complex disease pathologies. As such, combining antiangiogenic and chemotherapeutic drugs within multimodal nanocarriers synergistically augments the clinical efficiency of the drugs. This study reports the combinatorial efficacy of heparin (Hep), selenium NPs (SeNPs), and doxorubicin (Dox) to inhibit tumor growth and progression. Both Se@Hep-NPs and Se@Hep-Dox-NPs with excellent water dispersity having a size and charge in the range of 250 ± 5 and 253 ± 5 nm and -53 ± 0.4 and -48.4 ± 6.4 mV, respectively, showed strong anticancer potential assessed through in vitro assays like cell viability, specificity, colony formation, and wound scratch in MCF7 cells. Strong synergistic interactions among SeNPs, Hep, and Dox in Se@Hep-Dox-NPs render it to be an antiangiogenic and proapoptotic cancer cell death inducers. In vivo imaging highlights the dual-mode attributes of Se@Hep-NPs with desirable passive tumor targeting and biomedical imaging ability when tagged with Cy7.5, while Se@Hep-Dox-NPs significantly reduce the tumor burden and prolong the longevity of subcutaneous EAC-bearing mice. Histopathology studies reveal no signs of toxicity in major organs. Collectively, these results qualify Se@Hep-Dox-NPs as a plausible clinical therapeutic candidate.

A 2,5-Dihydroxybenzoic Acid-Gelatin Conjugate Inhibits the Basal and Hsp90-Stimulated Migration and Invasion of Tumor Cells

The extracellular cell surface-associated and soluble heat shock protein 90 (Hsp90) is known to participate in the migration and invasion of tumor cells. Earlier, we demonstrated that plasma membrane-associated heparan sulfate proteoglycans (HSPGs) bind the extracellular Hsp90 and thereby promote the Hsp90-mediated motility of tumor cells. Here, we showed that a conjugate of 2,5-dihydroxybenzoic acid with gelatin (2,5-DHBA–gelatin), a synthetic polymer with heparin-like properties, suppressed the basal (unstimulated) migration and invasion of human glioblastoma A-172 and fibrosarcoma HT1080 cells, which was accompanied by the detachment of a fraction of Hsp90 from cell surface HSPGs. The polymeric conjugate also inhibited the migration/invasion of cells stimulated by exogenous soluble native Hsp90, which correlated with the inhibition of the attachment of soluble Hsp90 to cell surface HSPGs. The action of the 2,5-DHBA–gelatin conjugate on the motility of A-172 and HT1080 cells was similar to that of heparin. The results demonstrate a potential of the 2,5-DHBA–gelatin polymer for the development of antimetastatic drugs targeting cell motility and a possible role of extracellular Hsp90 in the suppression of the migration and invasion of tumor cells mediated by the 2,5-DHBA–gelatin conjugate and heparin.

Traditional Chinese medicine combined with hepatic targeted drug delivery systems: A new strategy for the treatment of liver diseases

Liver diseases are clinically common and present a substantial public health issue. Many of the currently available drugs for the treatment of liver diseases suffer from limitations that include low hepatic distribution, lack of target effects, poor in vivo stability and adverse effects on other organs. Consequently, conventional treatment of hepatic diseases is ineffective. TCM is commonly used in the treatment of liver diseases worldwide, particularly in China, and has advantages over conventional therapy. HTDDS can be designed to enhance clinical efficacy in the treatment of liver diseases. We have conducted an extensive review of 335 studies reported since 1964. These included about 166 references involving the treatment of liver diseases with TCM (covering active components of TCM, single TCM and Chinese medicine formulas), 169 reports on HTDDS and background studies on liver-related diseases. Here we review the long history of TCM in the treatment of liver diseases.We have also reviewed the status of studies on active components of TCM using nanotechnology-based targeted delivery systems to provide support for further research and development of TCM-based targeted preparations for the treatment of liver disease.

Recent Developments in the Separation of Low Molecular Weight Heparin Anticoagulants

The general function of anticoagulants is to prevent blood clotting and growing of the existing clots in blood vessels. In recent years, there has been a significant improvement in developing methods of prevention as well as pharmacologic and surgical treatment of thrombosis. For over the last two decades, low molecular weight heparins (LMWHs) have found their application in the antithrombotic diseases treatment. These types of drugs are widely used in clinical therapy. Despite the biological and medical importance of LMWHs, they have not been completely characterized in terms of their chemical structure. Due to both, the structural complexity of these anticoagulants and the presence of impurities, their structural characterization requires the employment of advanced analytical techniques. Since separation techniques play the key role in these endeavors, this review will focus on the presentation of recent developments in the separation of LMWH anticoagulants.

Targeting heparin and heparan sulfate protein interactions

Heparin and heparan sulfate glycosaminoglycans are long, linear polysaccharides that are made up of alternating dissacharide sequences of sulfated uronic acid and amino sugars. Unlike heparin, which is only found in mast cells, heparan sulfate is ubiquitously expressed on the cell surface and in the extracellular matrix of all animal cells. These negatively-charged glycans play essential roles in important cellular functions such as cell growth, adhesion, angiogenesis, and blood coagulation. These biomolecules are also involved in pathophysiological conditions such as pathogen infection and human disease. This review discusses past and current methods for targeting these complex biomolecules as a novel therapeutic strategy to treating disorders such as cancer, neurodegenerative diseases, and infection.

Anticoagulation, ferrotoxicity and the future of translational lung cancer research

Numerous studies have shown that elements of coagulation reactions mediate tumor cell proliferation, motility (invasiveness), tissue remodeling and metastasis. Coagulation activation is virtually a universal feature of human malignancy that differs from the clotting response to injury in that it is self-perpetuating rather than self-attenuating. Coagulation activation participates in tumor matrix deposition and local inflammation, and predicts subsequent cancer risk and adverse cancer outcomes. Several clinical trials of anticoagulants have shown improved outcomes in small cell carcinoma of the lung (SCCL) that have been correlated with assembly on the tumor cells of an intact coagulation pathway. However, variable efficacy of anticoagulant therapy has raised doubts about the coagulation hypothesis. Recently, initiators of coagulation and fibrinolytic pathways have been identified that mediate tumor inception and progression. Notable among these is oxidative stress driven by iron-catalyzed reactive oxygen species that may be the basis for local coagulation activation, tumor matrix deposition, inflammation and aberrant properties characteristic of the malignant phenotype. Recognition of important biological characteristics of individual tumor types, disease stage, choice of standard therapy including chemotherapy and the iron status of the host may clarify mechanisms. All of these are subject to modification based on controlled clinical trial design. Further tests of the coagulation hypothesis may lead to novel, low cost and relatively non-toxic approaches to treatment of malignancy including lung cancer that contrast with certain current cancer treatment paradigms.

Circulating Tumor Cell Analyses in Patients With Esophageal Squamous Cell Carcinoma Using Epithelial Marker-Dependent and -Independent Approaches

In several epithelial malignancies, detection of circulating tumor cells (CTCs) in the peripheral blood has diagnostic, prognostic, and therapeutic implications. However, the clinical relevance of CTCs in esophageal squamous cell carcinoma (ESCC) has not yet been ascertained. The study was conducted with the aim of determining the clinical significance of CTCs in patients with ESCC by using 2 CTC detection systems, one epithelial marker-dependent and the other epithelial marker-independent. Paired peripheral blood samples were prospectively obtained from 61 ESCC patients before treatment and were analyzed for CTCs isolated by the CellSearch system (CS) and the method of isolation by size of epithelial tumor (ISET). Blood samples from 22 healthy volunteers were used as controls. Out of 61 study subjects, CTCs were detected in 20 patients (32.8%) by the ISET method and in only 1 patient (1.6%) by the CS method. Circulating tumor microemboli (CTM) were observed in 3 of 61 (4.9%) patients using ISET, but were undetectable in any of the patient by CS method. No CTCs/CTM were detected by either method in control groups. By ISET method, the presence of CTCs appeared to correlate with the stage of ESCC and with the baseline median platelet levels. No correlation with any other relevant clinicopathological variables was observed. Our results clearly indicate the ability of both CS and ISET methods to detect CTCs in peripheral blood samples from ESCC patients. However, the CellSearch system appears to have a poorer sensitivity as compared with the ISET method. Further studies are essential for assessing the role of such technologies in ESCC.

Heparin in malignant glioma: review of preclinical studies and clinical results

Glioblastoma multiforme (GBM) is the most common primary brain tumor that is invariably lethal. Novel treatments are desperately needed. In various cancers, heparin and its low molecular weight derivatives (LMWHs), commonly used for the prevention and treatment of thrombosis, have shown therapeutic potential. Here we systematically review preclinical and clinical studies of heparin and LMWHs as anti-tumor agents in GBM. Even though the number of studies is limited, there is suggestive evidence that heparin may have various effects on GBM. These effects include the inhibition of tumor growth and angiogenesis in vitro and in vivo, and the blocking of uptake of extracellular vesicles. However, heparin can also block the uptake of (potential) anti-tumor agents. Clinical studies suggest a non-significant trend of prolonged survival of LMWH treated GBM patients, with some evidence of increased major bleedings. Heparin mimetics lacking anticoagulant effect are therefore a potential alternative to heparin/LMWH and are discussed as well.

Analysis of incidence and clinical outcomes in patients with thromboembolic events and invasive exocrine pancreatic cancer

BACKGROUND

Pancreatic adenocarcinoma is among the most common malignancies associated with thromboembolic events (TEs); however, reported incidence figures vary significantly and contain small patient cohorts. Pancreatic cancer-specific thrombosis studies examining the correlation between clinical variables, including thrombosis timing and the impact of thrombosis on survival, have not been reported.

METHODS

Survival analyses were performed relating to the development and timing of a TE in 1915 patients administered chemotherapy at Memorial Sloan-Kettering Cancer Center with invasive exocrine pancreatic cancer from January 1, 2000 to December 31, 2009. TE timing, relative to clinical parameters including laboratory data, erythropoietin-stimulating agent use, and body mass index (BMI), were also analyzed.

RESULTS

A thrombosis was identified in 690 (36%) patients. After adjusting for patients with pancreatic surgery and thrombosis (n = 127), developing a TE significantly increased the risk of death (hazard ratio [HR], 2.6; 95% confidence interval [CI], 2.3-2.8; P < .01). Patients with an early TE (within 1.5 months from pancreatic cancer diagnosis) had a significantly higher risk of death (HR, 2.1; 95% CI, 1.7-2.5; P < .01) compared with patients with late TE or no TE. Erythropoietin-stimulating agent use and an elevated international normalized ratio were associated with significantly shorter time to thrombosis. Low BMI was associated with significantly longer time to thrombosis.

CONCLUSIONS

TEs are common in exocrine pancreatic cancer, with coagulopathy, erythropoietin-stimulating agent use, and underweight BMI influencing thrombosis timing. TEs, particularly early ones, confer a significantly worse prognosis, suggesting a biological significance, underscoring the relevance of ongoing prophylaxis trials, and raising the question of whether early TEs should be considered a stratification factor for clinical trials.

The low-molecular-weight heparin, nadroparin, inhibits tumour angiogenesis in a rodent dorsal skinfold chamber model

BACKGROUND

Recently, low-molecular-weight heparins (LMWHs) were found to confer a survival advantage in cancer patients. The mechanism underlying this observation is unclear, but may involve inhibition of tumour angiogenesis. We aimed to examine the effects of nadroparin on tumour angiogenesis using a dorsal skinfold window chamber model in the Syrian hamster.

METHODS

AMel-3 and HAP-T1 tumours were grown in donor animals and fragments implanted in the window chambers. Animals (N=46) were treated with 200 IU of nadroparin or saline for 10 days. Repeated intravital fluorescence microscopy was performed to calculate functional microcirculatory parameters: number (N) and length (L) of microvessels, vascular area fraction (AF), and red blood cell velocity (V). Microvessel density (MVD), fractal dimension, and pericyte coverage were assessed histologically.

RESULTS

Active angiogenesis was observed in control animals, resulting in a significant increase in N, L, and AF. In nadroparin-treated animals, however, N and L did not increase whereas AF decreased significantly. Both groups showed an initial increase in V, but nadroparin treatment resulted in an earlier decrease in red blood cell velocity over time. Compared with control animals, nadroparin-treated animals showed a significantly lower MVD and fractal dimension but significantly higher pericyte coverage index (PCI).

CONCLUSIONS

Taken together, these results suggest that the LMWH nadroparin inhibits tumour angiogenesis and results in microvessel normalisation.

Deadly allies: the fatal interplay between platelets and metastasizing cancer cells

The general notion that functional platelets are important for successful hematogenous tumor metastasis has been inaugurated more than 4 decades ago and has since been corroborated in numerous experimental settings. Thorough preclinical investigations have, at least in part, clarified some specifics regarding the involvement of platelet adhesion receptors, such as thrombin receptors or integrins, in the metastasis cascade. Pivotal preclinical experiments have demonstrated that hematogenous tumor spread was dramatically diminished when platelets were depleted from the circulation or when functions of platelet surface receptors were inhibited pharmacologically or genetically. Such insight has inspired researchers to devise novel antitumoral therapies based on targeting platelet receptors. However, several mechanistic aspects underlying the impact of platelet receptors on tumor metastasis are not fully understood, and agents directed against platelet receptors have not yet found their way into the clinic. In addition, recent results suggesting that targeted inhibition of certain platelet surface receptors may even result in enhanced experimental tumor metastasis have demonstrated vividly that the role of platelets in tumor metastasis is more complex than has been anticipated previously. This review gives a comprehensive overview on the most important platelet receptors and their putative involvement in hematogenous metastasis of malignant tumors.

Modular synthesis of heparan sulfate oligosaccharides for structure-activity relationship studies

Although hundreds of heparan sulfate binding proteins have been identified and implicated in a myriad of physiological and pathological processes, very little information is known about the ligand requirements for binding and mediating biological activities by these proteins. This difficulty results from a lack of technology for establishing structure-activity relationships, which in turn is due to the structural complexity of natural heparan sulfate (HS) and difficulties of preparing well-defined HS oligosaccharides. To address this deficiency, we developed a modular approach for the parallel combinatorial synthesis of HS oligosaccharides that utilizes a relatively small number of selectively protected disaccharide building blocks, which can easily be converted into glycosyl donors and acceptors. The utility of the modular building blocks has been demonstrated by the preparation of a library of 12 oligosaccharides, which has been employed to probe the structural features of HS for inhibiting the protease, BACE-1. The complex variations in activity with structural changes support the view that important functional information is embedded in HS sequences. Furthermore, the most active derivative provides an attractive lead compound for the preparation of more potent compounds, which may find use as a therapeutic agent for Alzheimer's disease.