Magnifying endoscopic observation of the gastric mucosa, particularly in patients with atrophic gastritis

Towards an emerging role for anticoagulants in cancer therapy: a systematic review and meta-analysis

Background

Anticoagulants, renowned for their role in preventing blood clot formation, have captivated researchers' attention for the exploitation of their potential to inhibit cancer in pre-clinical models.

Objectives

To undertake a systematic review and meta-analysis of the effects of anticoagulants in murine cancer research models. Further, to present a reference tool for anticoagulant therapeutic modalities relating to future animal pre-clinical models of cancer and their translation into the clinic.

Methods

Four databases were utilized including Medline (Ovid), Embase (Ovid), Web of science, and Scopus databases. We included studies relating to any cancer conducted in murine models that assessed the effect of traditional anticoagulants (heparin and its derivatives and warfarin) and newer oral anticoagulants on cancer.

Results

A total of 6,158 articles were identified in an initial multi-database search. A total of 157 records were finally included for data extraction. Studies on heparin species and warfarin demonstrated statistically significant results in favour of tumour growth and metastasis inhibition.

Conclusion

Our findings constitute a valuable reference guide for the application of anticoagulants in cancer research and explore the promising utilization of non-anticoagulants heparin in preclinical cancer research.

Systematic Review Registration

PROSPERO [CRD42024555603].

Therapeutic Potentials of Medicinal Leech in Chinese Medicine

The use of medicinal leeches in clinical therapy has been employed for a long time, as it was originally recognized for exerting antithrombin effects. These effects were due to the ability of the leech to continuously suck blood while attached to human skin. According to Chinese Pharmacopoei, leeches used in traditional Chinese medicine mainly consist of Whitmania pigra Whitman, Hirudo nipponia Whitman, and Whitmania acranulata, but the latter two species are relatively scarce. The main constituents of leeches are protein and peptide macromolecules. They can be categorized into two categories based on their pharmacological effects. One group consists of active ingredients that directly target the coagulation system, such as hirudin, heparin, and histamine, which are widely known. The other group comprises protease inhibitor components like Decorsin and Hementin. Among these, hirudin secreted by the salivary glands of the leech is the most potent thrombin inhibitor and served as the sole remedy for preventing blood clotting until the discovery of heparin. Additionally, leeches play a significant role in various traditional Chinese medicine formulations. In recent decades, medicinal leeches have been applied in fields including anti-inflammatory treatment, cardiovascular disease management, antitumor treatment, and many other medical conditions. In this review, we present a comprehensive overview of the historical journey and medicinal applications of leeches in various medical conditions, emphasizing their pharmaceutical significance within traditional Chinese medicine. This review offers valuable insights for exploring additional therapeutic opportunities involving the use of leeches in various diseases and elucidating their underlying mechanisms for future research.

Antiproliferative Properties of Scandium Exopolysaccharide Complexes on Several Cancer Cell Lines

Antimetastatic properties on both murine and human osteosarcoma cell lines (POS-1 and KHOS) have been evidenced using exopolysaccharide (EPS) derivatives, produced by Alteromonas infernus bacterium. These derivatives had no significant effect on the cell cycle neither a pro-apoptotic effect on osteosarcoma cells. Based on this observation, these EPSs could be employed as new drug delivery systems for therapeutic uses. A theranostic approach, i.e., combination of a predictive biomarker with a therapeutic agent, has been developed notably by combining with true pair of theranostic radionuclides, such as scandium ⁴⁷Sc/⁴⁴Sc. However, it is crucial to ensure that, once complexation is done, the biological properties of the vector remain intact, allowing the molecular tropism of the ligand to recognize its molecular target. It is important to assess if the biological properties of EPS evidenced on osteosarcoma cell lines remain when scandium is complexed to the polymers and can be extended to other cancer cell types. Scandium-EPS complexes were thus tested in vitro on human cell lines: MNNG/HOS osteosarcoma, A375 melanoma, A549 lung adenocarcinoma, U251 glioma, MDA231 breast cancer, and Caco2 colon cancer cells. An xCELLigence Real Cell Time Analysis (RTCA) technology assay was used to monitor for 160 h, the proliferation kinetics of the different cell lines. The tested complexes exhibited an anti-proliferative effect, this effect was more effective compared to EPS alone. This increase of the antiproliferative properties was explained by a change in conformation of EPS complexes due to their polyelectrolyte nature that was induced by complexation. Alterations of both growth factor-receptor signaling, and transmembrane protein interactions could be the principal cause of the antiproliferative effect. These results are very promising and reveal that EPS can be coupled to scandium for improving its biological effects and also suggesting that no major structural modification occurs on the ligand.

A systematic review on the efficacy and safety of low molecular weight heparin as an anticancer therapeutic in preclinical animal models

OBJECTIVE

The therapeutic effects of low molecular weight heparins (LMWH) may extend past thrombosis prevention, with preclinical evidence demonstrating anti-metastatic properties. Clinical evidence on the topic, however, remains controversial. A systematic review of preclinical evidence may help elucidate reasons for this contradictory evidence. The objective of our systematic review is to assess the anti-metastatic properties of LMWHs in solid tumour animal models.

METHODS

MEDLINE, Embase, Web of Science and PubMed were searched from inception to May 12th, 2020. All articles were screened independently and in duplicate. Studies that compared LMWH to a placebo or no treatment arm in solid tumour animal models were included. The primary outcome was the burden of metastasis. Secondary outcomes included primary tumour growth and mortality. The risk of bias was assessed in duplicate using a modified Cochrane Risk of Bias tool.

RESULTS

Forty-two studies were included in the review. Administration of a LMWH was associated with a significant decrease in the burden of metastasis (SMD -2.18; 95% CI -2.66 to -1.70). Additionally, the administration of a LMWH was also associated with a significant reduction in primary tumour growth (SMD -1.95; 95% CI -2.56 to -1.34) and risk of death (RR 0.39; 95% CI 0.16-0.97). All included studies were deemed to be at an unclear risk of bias for at least one methodological criterion.

CONCLUSIONS

Our results demonstrate that LMWH can effectively reduce metastatic burden and reduce tumour growth in preclinical animal models of solid tumour malignancies. Reasons for the contradiction with clinical evidence require further exploration.

In vitro antitumor and anti-angiogenic activities of a shrimp chondroitin sulfate

Thrombin triggers cellular responses that are crucial for development and progression of cancer, such as proliferation, migration, oncogene expression and angiogenesis. Thus, biomolecules capable of inhibiting this protease have become targets in cancer research. The present work describes the in vitro antitumor properties of a chondroitin sulfate with anti-thrombin activity, isolated from the Litopenaeus vannamei shrimp (sCS). Although the compound was unable to induce cytotoxicity or cell death and/or cell cycle changes after 24 h incubation, it showed a long-term antiproliferative effect, reducing the tumor colony formation of melanoma cells by 75% at 100 μg/mL concentration and inhibiting the anchorage-independent colony formation. sCS reduced 66% of melanoma cell migration in the wound healing assay and 70% in the transwell assay. The compound also decreased melanin and TNF-α content of melanoma cells by 52% and 75% respectively. Anti-angiogenic experiments showed that sCS promoted 100% reduction of tubular structure formation at 100 μg/mL. These results are in accordance with the sCS-mediated in vitro expression of genes related to melanoma development (Cx-43, MAPK, RhoA, PAFR, NFKB1 and VEGFA). These findings bring a new insight to CS molecules in cancer biology that can contribute to ongoing studies for new approaches in designing anti-tumor therapy.

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.

The direct oral anticoagulants rivaroxaban and dabigatran do not inhibit orthotopic growth and metastasis of human breast cancer in mice

Essentials Factor Xa (FXa)-targeting direct oral anticoagulants (DOACs) reduce venous thromboembolism (VTE) The effects of FXa-targeting DOACs on cancer progression remain to be studied In xenograft models, a FXa-targeting DOAC did not inhibit breast cancer growth and metastasis A thrombin-targeting DOAC, dabigatran, also did not inhibit breast cancer growth and metastasis ABSTRACT: Background Factor Xa-targeting DOACs were recently found to reduce recurrent VTE efficiently in cancer patients when compared to the standard treatment with low-molecular-weight heparins (LMWHs). While the anticancer effects of LMWHs have been extensively studied in preclinical cancer models, the effects of FXa-targeting DOACs on cancer progression remain to be studied. Objective We investigated whether the FXa-targeting DOAC rivaroxaban and the thrombin-targeting DOAC dabigatran etexilate (DE) affected human breast cancer growth and metastasis in orthotopic xenograft models. Methods/results Mice that were put on a custom-made chow diet supplemented with rivaroxaban (0.4 or 1.0 mg/g diet) or dabigatran etexilate (DE) (10 mg/g diet) showed prolonged ex vivo coagulation times (prothrombin time [PT] and activated partial thromboplastin time [aPTT] assay, respectively). However, rivaroxaban and DE did not inhibit MDA-MB-231 tumor growth and metastasis formation in lungs or livers of 7-week-old fully immunodeficient NOD/SCID/ƴC-/- (NSG) mice. Comparable data were obtained for rivaroxaban-treated mice when using NOD-SCID mice. Rivaroxaban and DE treatment also did not significantly inhibit tumor growth and metastasis formation when using another human triple negative breast cancer (TNBC) cell line (HCC1806) in NOD-SCID mice. The FXa and thrombin-induced gene expression of the downstream target CXCL8 in both cell lines, but FXa and thrombin, did not significantly stimulate migration, proliferation, or stemness in vitro. Conclusion Although effectively inhibiting coagulation, the DOACs rivaroxaban and DE did not inhibit orthotopic growth and metastasis of human TNBC. It remains to be investigated whether DOACs exert antitumorigenic effects in other types of cancer.

Low molecular weight heparin and direct oral anticoagulants influence tumour formation, growth, invasion and vascularisation by separate mechanisms

The bidirectional association between coagulation and cancer has been established. However, anticoagulant therapies have been reported to have beneficial outcomes by influencing the vascularisation of the tumours. In this study the influence of a set of anticoagulants on tumour formation, invasion and vascularisation was examined. WM-266-4 melanoma and AsPC-1 pancreatic cancer cell lines were treated with LMWH (Tinzaparin and Dalteparin), and DOAC (Apixaban and Rivaroxaban) and the rate of tumour formation, growth and invasion were measured in vitro. In addition, the influence of these anticoagulants on vascularisation was examined using the chorioallantoic membrane assay (CAM) model and compared to the outcome of treatment with Bevacizumab. Using this model the influence of pharmacological concentrations of the anticoagulant on the growth, invasion and vascularisation of tumours derived from WM-266-4 and AsPC-1 cells was also measured in vivo. Tinzaparin and Daltepain reduced tumour formation and invasion by the cell lines in vitro, but with dissimilar potencies. In addition, treatment of CAM with LMWH reduced the local vascular density beyond that achievable with Bevacizumab, particularly suppressing the formation of larger-diameter blood vessels. In contrast, treatment with DOAC was largely ineffective. Treatment of CAM-implanted tumours with LMWH also reduced tumour vascularisation, while treatment of tumours with Apixaban reduced tumour growth in vivo. In conclusion, LMWH and DOAC appear to have anti-cancer properties that are exerted through different mechanisms.

Endothelial barrier protective properties of low molecular weight heparin: A novel potential tool in the prevention of cancer metastasis?

BACKGROUND

One of the key events in the progression of cancer metastasis is the trans-endothelial migration of circulating tumor cells. Moreover, inhibition of tumor-induced vascular permeability has been shown to inhibit metastasis in vivo. Low molecular weight heparin (LMWH) appears to confer a survival benefit in cancer but the underlying mechanisms are poorly understood.

OBJECTIVE

To characterise LMWH-mediated endothelial barrier protection and to explore strategies to limit the LMWH-associated haemorrhagic risk in this setting.

METHODS

Endothelial barrier function was assessed using in vitro assays of endothelial permeability and tumor cell trans-endothelial migration. Thrombin-mediated activation of PAR-1 signalling was assessed by flow cytometry and western blotting. LMWH anticoagulant activity was assessed by calibrated automated thrombography and plasma anti-factor Xa activity assay.

RESULTS

LMWH tinzaparin enhanced endothelial barrier function and reduced tumor cell trans-endothelial migration (73.9±5.7% of baseline; P<.05). Tinzaparin-mediated attenuation of thrombin-induced permeability was not mediated through an inhibition of thrombin proteolytic activity. In addition, fractions of LMWH with diminished anticoagulant activity retained endothelial barrier protective properties and a marked synergistic effect on barrier function was observed using combinations of sub-anticoagulant concentrations of tinzaparin with simvastatin (which exhibits endothelial barrier protective properties in vitro), with almost complete protection against agonist-induced endothelial barrier permeability achieved (7.9±0.2% of baseline; P<.05).

CONCLUSION

Collectively, these results suggest that LMWH supports endothelial barrier function in a manner which does not appear to be dependent on its anticoagulant activity. If replicated in vivo, these findings could represent a novel therapeutic approach to the suppression of metastasis.

Anticoagulants versus cancer

Venous thromboembolism (VTE) and cancer are strongly associated, and present a major challenge in cancer patient treatment. Cancer patients have a higher risk of developing VTE, although the risk differs widely between tumour types. VTE prophylaxis is routinely given to cancer patients, in the form of vitamin K antagonists (VKA) or low molecular weight heparin (LMWH). Several studies have reported that cancer patients receiving anticoagulants show prolonged survival and this effect was more pronounced in patients with a good prognosis, although the mechanism is poorly understood. Tissue Factor (TF) is the initiator of extrinsic coagulation, but its non-haemostatic signalling via protease-activated receptors (PARs) is a potent driver of tumour angiogenesis. Furthermore, coagulation activation is strongly implicated in tumour cell migration and metastasis. This review discusses the effects of anticoagulants on cancer progression in patients, tumour cell behaviour, angiogenesis, and metastasis in in vitro and in vivo models. Inhibition of TF signalling shows great promise in curbing angiogenesis and in vivo tumour growth, but whether this translates to patients is not yet known. Furthermore, non-haemostatic properties of coagulation factors in cancer progression are discussed, which provide exciting opportunities on limiting oncologic processes without affecting blood coagulation.

Emodin-Loaded PLGA-TPGS Nanoparticles Combined with Heparin Sodium-Loaded PLGA-TPGS Nanoparticles to Enhance Chemotherapeutic Efficacy Against Liver Cancer

PURPOSE

Heparin sodium (HS)-loaded polylactic-co-glycolic acid-D-α-tocopheryl polyethylene glycol 1000 succinate (PLGA-TPGS) nanoparticles (HPTNs) were prepared as a sustained and targeting delivery carrier and combined with emodin (EMO)-loaded PLGA-TPGS nanoparticles (EPTNs), which were investigated previously to form a combination therapy system for the treatment of liver cancer.

METHODS

To assess cellular uptake and evaluate the liver-targeting capacity by analyzing the drug concentrations and frozen slices, HS/eosin-loaded PLGA-TPGS nanoparticles, HS/fluorescein- loaded PLGA-TPGS nanoparticles and EMO/C6-loaded PLGA-TPGS nanoparticles, which contained eosin, fluorescein and C6 as fluorescent probes, respectively, were also prepared. All of these nanoparticles were characterized in terms of their size, size distribution, surface charge, drug loading, encapsulation efficiency, in vitro release profile and cellular uptake. The apoptosis of HepG2 cells induced by EPTNs in combination with HPTNs was determined by Annexin V-FITC staining and PI labelling.

RESULTS

Transmission electron microscopy indicated that these nanoparticles were stably dispersed spheres with sizes ranging from 100 to 200 nm. The results demonstrated that fluorescent nanoparticles were internalized into HepG2 and HCa-F cells efficiently and had improved liver-targeting properties. The combination of EPTNs and HPTNs effectively inhibited cell growth in vitro and had a remarkable synergistic anticancer effect in vivo. EPTNs combined with HPTNs induced HepG2 cell apoptosis with synergistic effects. The liver H&E slice images of a hepatocarcinogenic mouse model indicated that EPTNs in combination with HPTNs significantly suppressed tumour growth in vivo.

CONCLUSIONS

The research suggests that the combination therapy system of EPTNs and HPTNs could be a new direction for liver cancer therapy.

Extracellular vesicles from malignant effusions induce tumor cell migration: inhibitory effect of LMWH tinzaparin

Elevated levels of extracellular vesicles (EVs) have been correlated with inflammatory diseases as well as progressive and metastatic cancer. By presenting tissue factor (TF) on their membrane surface, cellular microparticles (MPs) activate both the coagulation system and cell-signaling pathways such as the PAR/ERK pathway. We have shown before that malignant effusions are a rich source of tumor cell-derived EVs. Here, we used EVs from malignant effusions from three different patients after serial low-speed centrifugation steps as recommended by the ISTH (lsEV). Significant migration of human pancreatic carcinoma cells could be induced by lsEVs and was effectively inhibited by pre-incubation with tinzaparin, a low-molecular-weight heparin. Tinzaparin induced tissue factor pathway inhibitor (TFPI) release from tumor cells, and recombinant TFPI inhibited EV-induced tumor cell migration. EVs also induced ERK phosphorylation, whereas inhibitors of PAR2 and ERK suppressed EV-induced tumor cell migration. LsEVs have been characterized by high-resolution flow cytometry and, after elimination of smaller vesicles including exosomes, by further high-speed centrifugation (hsEV). The remaining population consisting primarily of MPs is indeed the main migration-inducing population with tenase activity. Compared to other LMWHs, tinzaparin is suggested to have high potency to induce TFPI release from epithelial cells. The migration-inhibitory effect of TFPI and the interruption of tumor cell migration by inhibitors of PAR2 and ERK suggest that lsEVs induce tumor cell migration by activating the PAR2 signaling pathway. Tinzaparin might inhibit this process at least partly by inducing the release of TFPI from tumor cells, which blocks PAR-activating TF complexes. The clinical relevance of the results is discussed.

Low-molecular-weight heparins and cancer: focus on antitumoral effect

A close relationship between cancer and thrombosis does exist, documented by the fact that an overall 7-fold increased risk of venous thromboembolism (VTE) has been reported in patients with malignancy compared to non-malignancy. The potential impact of antithrombotic agents in cancer-associated VTE has long been recognized, and, in particular, several clinical trials in the last 20 years have reported the safety and efficacy of low-molecular-weight heparins (LMWHs) for treatment and prophylaxis of VTE in patients with various types of cancer. More recently, a number of preclinical and clinical studies have suggested that LMWHs may improve survival in cancer patients with mechanisms that are different from its antithrombotic effect but are linked to the ability of influencing directly the tumor biology. This paper reviews the evidence around the potential survival benefits of LMWHs by analyzing the suggested mechanisms and the available clinical data.

Significantly inhibitory effects of low molecular weight heparin (Fraxiparine) on the motility of lung cancer cells and its related mechanism

Low molecular weight heparin (LMWH) improving the cancer survival has been attracting attention for many years. Our previous study found that LMWH (Fraxiparine) strongly downregulated the invasive, migratory, and adhesive ability of human lung adenocarcinoma A549 cells. Here, we aimed to further identify the antitumor effects and possible mechanisms of Fraxiparine on A549 cells and human highly metastatic lung cancer 95D cells. The ability of cell invasion, migration, and adhesion were measured by Transwell, Millicell, and MTT assays. FITC-labeled phalloidin was used to detect F-actin bundles in cells. Chemotactic migration was analyzed in a modified Transwell assay. Measurement of protein expression and phosphorylation activity of PI3K, Akt, and mTOR was performed with Western blot. Our studies found that Fraxiparine significantly inhibited the invasive, migratory, and adhesive characteristics of A549 and 95D cells after 24 h incubation and showed a dose-dependent manner. Fraxiparine influenced the actin cytoskeleton rearrangement of A549 and 95D cells by preventing F-actin polymerization. Moreover, Fraxiparine could significantly inhibit CXCL12-mediated chemotactic migration of A549 and 95D cells in a concentration-dependent manner. Furthermore, Fraxiparine might destroy the interaction between CXCL12-CXCR4 axis, then suppress the PI3K-Akt-mTOR signaling pathway in lung cancer cells. For the first time, our data indicated that Fraxiparine could significantly inhibit the motility of lung cancer cells by restraining the actin cytoskeleton reorganization, and its related mechanism might be through inhibiting PI3K-Akt-mTOR signaling pathway mediated by CXCL12-CXCR4 axis. Therefore, Fraxiparine would be a potential drug for lung cancer metastasis therapy.

Heparan sulfate proteoglycans and heparin regulate melanoma cell functions

BACKGROUND

The solid melanoma tumor consists of transformed melanoma cells, and the associated stromal cells including fibroblasts, endothelial cells, immune cells, as well as, soluble macro- and micro-molecules of the extracellular matrix (ECM) forming the complex network of the tumor microenvironment. Heparan sulfate proteoglycans (HSPGs) are an important component of the melanoma tumor ECM. Importantly, there appears to be both a quantitative and a qualitative shift in the content of HSPGs, in parallel to the nevi-radial growth phase-vertical growth phase melanoma progression. Moreover, these changes in HSPG expression are correlated to modulations of key melanoma cell functions.

SCOPE OF REVIEW

This review will critically discuss the roles of HSPGs/heparin in melanoma development and progression.

MAJOR CONCLUSIONS

We have correlated HSPGs' expression and distribution with melanoma cell signaling and functions as well as angiogenesis.

GENERAL SIGNIFICANCE

The current knowledge of HSPGs/heparin biology in melanoma provides a foundation we can utilize in the ongoing search for new approaches in designing anti-tumor therapy. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties.

Heparin plays a key regulatory role via a p53/FAK-dependent signaling in melanoma cell adhesion and migration

Heparin and its various derivatives affect cancer progression in humans. In this study, we show that heparin uptaken intracellularly by melanoma cells activated a signaling cascade, which in turn inhibited melanoma cell adhesion and migration. The reduced ability of M5 cells to adhere onto the fibronectin (FN) substrate was directly correlated to a decrease in the expression of focal adhesion kinase (FAK), which is a key regulator of melanoma motility. Cell treatment with heparin caused a marked downregulation in FAK expression (P ≤ 0.01). This is followed by an analogous inhibition of both constitutive and FN-induced FAK Y397-phosphorylation (P ≤ 0.01). Moreover, heparin stimulated the p53 expression (P ≤ 0.001) of M5 cells and its increased accumulation in the nucleus. This favors a decrease in FAK promoter activation and explains the reduced FAK transcript and protein levels. In conclusion, the results of this study clearly demonstrate that the action of heparin in the regulation of melanoma cell adhesion and migration involves a p53/FAK/signaling pathway, which may be of importance in molecular targeted therapy of the disease.

Inhibitory effect of dalteparin sodium on the growth of early-stage hepatocellular carcinoma

AIM: To investigate the inhibition of dalteparin sodium (low molecular weight heparins) on early hepatocellular carcinoma (HCC) in nude mice.

METHODS: The metastatic model of HCC was established in 40 nude mice, which were randomly divided into 4 groups: control group (treated with saline), chemotherapy group (treated with 5-fluorouracil and cis-dichlorodiamine platinum), dalteparin sodium treatment group, and combined treatment group (treated with dalteparin sodium, 5-fluorouracil and cis-dichlorodiamine platinum). The following parameters, such as tumor size, tumor inhibition rates, alpha fetoprotein (AFP) and intratumoral microvessel density (MVD), were evaluated respectively 14 d after operation.

RESULTS: In comparison with that in the control group, the tumor size was significantly reduced in the chemotherapy group, dalteparin sodium group and combined group (26.25 ± 11.55, 33.70 ± 14.78, 17.25 ± 6.80 mm³vs 68.47 ± 22.04 mm³; all P < 0.05); the tumor inhibition rates showed that dalteparin sodium had a satisfactory depressing effect on tumor growth. The MVD values were markedly lower in the dalteparin sodium group and combined group than those in the control group and chemotherapy group (5.2 ± 1.55, 4.7 ± 2.21 vs 19.34 ± 3.57, 17.1 ± 3.03; all P < 0.05). Moreover, the level of alpha-fetoprotein was significantly decreased in the chemotherapy group, dalteparin sodium group and combined group as compared with that in the control group (14.56 ± 8.87 mg/L, 13.36 ± 7.60 mg/L, 11.57 ± 7.82 mg/L vs 22.20 ± 6.29 mg/L, all P < 0.05).

CONCLUSION: Dalteparin sodium can suppress tumor growth and metastasis by inhibiting tumor angiogenesis of early-stage HCC.

A recombinant peptide, hirudin, potentiates the inhibitory effects of stealthy liposomal vinblastine on the growth and metastasis of melanoma

The metastasis of tumor cells is one of the major obstacles to successful clinical therapy. A treatment strategy by incorporating a specific inhibitor of thrombin, recombinant hirudin with stealthy liposomal vinblastine, was used in this study for inhibiting the metastasis of tumor cells and enhancing the efficacy of anti-tumor agents. In vitro cytotoxicity, cell adhesion to extracellular matrix (ECM) proteins, and cell invasion and migration assays were performed on human A375 melanoma cell line. In vivo measurement of coagulation parameters, inhibition of tumor growth, and inhibition of metastasis were assessed in female BALB/c mice. In vitro, vinblastine or stealthy liposomal vinblastine alone was effective to inhibit the growth of A375 cells. On the contrary, hirudin had no influence on either cytotoxicity when treating with hirudin alone or hirudin plus vinblastine. In addition, in vitro results showed that hirudin had no impact on the adhesion of tumor cells to extracellular matrix proteins, and metastasis and invasion of tumor cells. In mice, hirudin significantly inhibited the activity of thrombin. Furthermore, administered at the initial implantation of murine B16 melanoma cells, hirudin evidently delayed the growth of tumor, and depressed the occurrence of experimental lung metastasis. A subsequent administration of stealthy liposomal vinblastine resulted in further inhibiting growth and metastasis of tumor, indicating that hirudin plus stealthy liposomal vinblastine exhibited a significant anti-metastasis effect and slightly potent effect against tumor growth as compared with stealthy liposomal vinblastine alone. In conclusion, administration of recombinant hirudin followed by giving stealthy liposomal vinblastine may be beneficial for inhibiting the growth and metastasis of melanoma in vivo. The likely mechanism could be associated with inhibition of thrombin after administration of hirudin.

The thrombin inhibitor Argatroban reduces breast cancer malignancy and metastasis via osteopontin-dependent and osteopontin-independent mechanisms

Osteopontin (OPN) has been clinically and experimentally associated with breast cancer metastasis. Proteolytic cleavage of OPN by thrombin has been reported to increase its biologic activity. The purpose of this study was to determine if inhibition of thrombin could reduce the malignancy-promoting effects of OPN on breast cancer cell behavior in vitro and in vivo. MDA-MB-468 human breast cancer cells were stably transfected to overexpress OPN (468-OPN) or a control vector (468-CON) and compared for functional differences in malignant/metastatic behavior in response to treatment with the thrombin-specific inhibitor Argatroban. Western blot analysis revealed that both 468-CON and 468-OPN cells produce thrombin and the thrombin-related protein tissue factor, and express very low levels of thrombin receptor (PAR-1). In vitro assays demonstrated that Argatroban treatment (25 microg/ml) of 468-OPN cells resulted in decreased cell growth, colony-forming ability, adhesion, and migration relative to untreated controls (P < 0.05), but did not have a significant effect on 468-CON cells. Following mammary fat pad injection, treatment with Argatroban (9 mg/kg/day) increased the in vivo tumor latency of both 468-CON and 468-OPN cells, and reduced primary tumor growth of 468-OPN cells (relative to untreated controls; P < 0.05). Furthermore, Argatroban treatment significantly decreased lymphatic metastasis of both 468-CON (P < 0.04) and 468-OPN (P < 0.01) cells relative to untreated controls. These novel findings indicate that inhibition of thrombin can reduce malignant and metastatic behavior of MDA-MB-468 breast cancer cells using both OPN-dependent and OPN-independent mechanisms, and suggest that thrombin inhibitors such as Argatroban may hold potential as therapeutic agents to combat breast cancer progression.

Toxicogenomics of A375 human malignant melanoma cells

Toxicogenomics applications are increasingly applied to the evaluation of preclinical drug safety, and to explain toxicities associated with compounds at the mechanism level. In this review, we aim to describe the application of toxicogenomics tools for studying the genotoxic effect of active compounds on the gene-expression profile of A375 human malignant melanoma cells, through the other molecular functions of target genes, regulatory pathways and mechanisms of malignant melanomas. It also includes the current systems biology approaches, which are very useful for analyzing the biological system and understanding the entire mechanisms of malignant melanomas. We believe that this review would be very potent and useful for studying the toxicogenomics of A375 melanoma cells, and for further diagnostic and therapeutic applications.

Mechanisms of heparin induced anti-cancer activity in experimental cancer models

BACKGROUND

Retrospective analyses of clinical trials and prospective clinical studies have suggested that heparins may have an effect on cancer survival. This putative anti-cancer activity of heparins is supported by data from studies in animal tumour models.

OBJECTIVE

To clarify the various potential mechanisms of heparin anti-cancer activity we evaluated the data from pre-clinical studies in which heparins have been tested as anti-cancer therapy.

METHODS

Pre-clinical studies, published between 1960 and 2005 were assessed. Data were collected on the type and dose of heparin used, duration of exposure to heparin, interval between heparin administration and cancer cell inoculation, and the animal tumour model used. In addition, a distinction was made in the analysis between heparin effects on the primary tumour or on established metastases and effects on the metastatic potential of infused cells.

RESULTS

Heparins seemed to affect the formation of metastasis rather than the growth of primary tumours. Chemically modified heparins with no or limited anticoagulant activity also showed anti-metastatic properties. Possible mechanisms to explain the effects on the process of metastases include inhibition of blood coagulation, inhibition of cancer cell-platelet and -endothelial interactions by selectin inhibition and inhibition of cell invasion and angiogenesis.

CONCLUSION

The anti-cancer activity of heparins depends more on inhibition of metastasis formation than on the effects on primary tumour growth. These effects are probably related to both coagulation and non-coagulation dependent factors. For a definitive proof of the anti-cancer activity of heparins in the clinic, prospective randomized trials especially in patients with early metastatic disease or in the adjuvant setting are urgently needed.