Preliminary safety evaluation of a taurocholate-conjugated low-molecular-weight heparin derivative (LHT7): a potent angiogenesis inhibitor

Recent Progress on Heparin–Protamine Particles for Biomedical Application

Biomolecules are attractive building blocks with self-assembly ability, structural diversity, and excellent functionality for creating artificial materials. Heparin and protamine, a clinically relevant pair of biomolecules used in cardiac and vascular surgery, have been shown to coassemble into particulate polyelectrolyte complexes in vitro. The resulting heparin–protamine particles exhibit adhesive properties that enable advantageous interactions with proteins, cells, and various other substances and have been employed as functional materials for biomedical applications. In this review article, we summarize recent progress in research on the use of heparin–protamine particles as drug carriers, cell adhesives, and cell labels. Studies have demonstrated that heparin–protamine particles are potentially versatile in biomedical fields from drug delivery and regenerative medicine to plastic surgery.

Anticancer Effect of Heparin-Taurocholate Conjugate on Orthotopically Induced Exocrine and Endocrine Pancreatic Cancer

Simple Summary

Pancreatic cancer has a less than 9% 5-year survival rate among patients because it is very difficult to detect and diagnose early. Combinatorial chemotherapy with surgery or radiotherapy is a potential remedy to treat pancreatic cancer. However, these strategies still have side effects such as hair loss, skin soreness and fatigue. To overcome these side effects, angiogenesis inhibitors such as sunitinib are used to deliver targeted blood vessels around tumor tissues, including pancreatic cancer tumors. It is still controversial whether antiangiogenesis therapy is sufficient to treat pancreatic cancer. So far, many scientists have not been focused on the tumor types of pancreatic cancer when they have developed antipancreatic cancer medication. Here, we used heparin–taurocholate (LHT) as an anticancer drug to treat pancreatic cancer through inhibition of angiogenic growth factors. In this study, we examined the anticancer efficacy of LHT on various types of pancreatic cancer in an orthotopic model.

Abstract

Pancreatic cancers are classified based on where they occur, and are grouped into those derived from exocrine and those derived from neuroendocrine tumors, thereby experiencing different anticancer effects under medication. Therefore, it is necessary to develop anticancer drugs that can inhibit both types. To this end, we developed a heparin–taurocholate conjugate, i.e., LHT, to suppress tumor growth via its antiangiogenic activity. Here, we conducted a study to determine the anticancer efficacy of LHT on pancreatic ductal adenocarcinoma (PDAC) and pancreatic neuroendocrine tumor (PNET), in an orthotopic animal model. LHT reduced not only proliferation of cancer cells, but also attenuated the production of VEGF through ERK dephosphorylation. LHT effectively reduced the migration, invasion and tube formation of endothelial cells via dephosphorylation of VEGFR, ERK1/2, and FAK protein. Especially, these effects of LHT were much stronger on PNET (RINm cells) than PDAC (PANC1 and MIA PaCa-2 cells). Eventually, LHT reduced ~50% of the tumor weights and tumor volumes of all three cancer cells in the orthotopic model, via antiproliferation of cancer cells and antiangiogenesis of endothelial cells. Interestingly, LHT had a more dominant effect in the PNET-induced tumor model than in PDAC in vivo. Collectively, these findings demonstrated that LHT could be a potential antipancreatic cancer medication, regardless of pancreatic cancer types.

Anti-tumoral effects of low molecular weight heparins: A focus on the treatment of esophageal cancer

Esophageal cancer is one of the most prevalent types of cancer globally. With current treatment options, the survival is poor, and there are ongoing efforts to find new and more efficient therapeutic approaches. There are several reports on the anti-tumoral effects of low-molecular-weight heparins (LMWH). We have assessed the possible survival benefits and underlying mechanisms of LMWHs in malignancies with a focus on esophageal cancer. We conclude that the effects of LMWHs on survival of cancer patients is probably due to a combination of direct anti-tumoral, anti-angiogenic, and immunomodulatory effects and indirect effects on the coagulation system.

Low molecular weight heparin and cancer survival: clinical trials and experimental mechanisms

INTRODUCTION

The relationship between cancer and thrombosis is complex, as the hemostatic system is inextricably linked to the mechanisms of cancer growth and metastasis. The coagulation system thus appears to be a site for oncogenic events and necessary for the survival and spread of malignant cells. Although several meta-analyses on the effectiveness of unfractionated heparin and low molecular weight heparin (LMWH) in the treatment of venous thromboembolism (VTE) have suggested a lower mortality risk in cancer patients receiving LMWH, this contention has not received general acceptance. In fact, there exist no sufficiently powered studies to date supporting the routine use of LMWH to improve cancer survival. Meanwhile, the molecular mechanism underlying the anti-neoplastic effect of LMWH which is independent of its anti-coagulant function is largely unexplored and is a topic of active investigation.

MATERIALS AND METHODS

In this communication, we aimed to review comprehensively evidences from clinical trials, meta-analysis as well as experimental molecular research and to identify future research areas of importance so as to stimulate future research on the potential anti-tumor action of LMWH.

CONCLUSION

Although benefit of LMWH on cancer patients' survival is controversial depending on the tumor type, cancer stage as well as LMWH type, it appears to be associated with a reduction in VTE and increased bleeding is minor and controllable; thus, randomized controlled trials targeting the survival benefit of certain specific LWMH are needed and justified, and more in-depth experimental researches are imperative to elucidate the anti-tumor effect of anticoagulants.

Safety studies on intravenous infusion of a potent angiogenesis inhibitor: taurocholate-conjugated low molecular weight heparin derivative LHT7 in preclinical models

CONTEXT

As a class of angiogenesis inhibitors, heparin conjugates have shown significant effectiveness in several studies.

OBJECTIVES

The purpose of our current study is to evaluate the effectiveness and safety of infusing the conjugate of low molecular weight heparin and taurocholate (LHT7), which has been developed as a potent angiogenesis inhibitor.

METHODS

To evaluate its safety, the method of intravenous infusion was compared with its i.v. bolus administration. Intravenous infusion was administered at a rate of 400 μl/min/kg of body weight for 30 min. Pharmacokinetic (PK) analysis, organ accumulation, and plasma concentration profiles of LHT7 were measured. The anticancer effect of LHT7 was evaluated in murine and human xenograft models, and preclinical studies were performed in SD rats and beagle dogs.

RESULTS

The results of the PK studies showed reduced organ accumulation in mice and the AUC(0-96 h) (area under the curve) was increased up to 1485 ± 125 h × μg/ml. The efficacy, at dose 1 mg/kg/2 d was higher for i.v. infusion than for i.v. bolus administration in both murine and human cancer models. The preclinical studies showed the safety dose of LHT7 is less than 20 mg/kg in SD rats and in the next safety analysis in beagle dogs showed that there were no organ-specific adverse effects in higher doses, such as, 12 mg/kg. LHT7 showed sustained effects with minimized adverse events when administered through i.v. infusion.

CONCLUSIONS

LHT7 (i.v. infusion) could be safely used for further clinical development as a multi-targeting anti-angiogenic agent.

Chemical Conjugate of Low Molecular Weight Heparin and Suramin Fragment Inhibits Tumor Growth Possibly by Blocking VEGF165

Low molecular weight heparin (LMWH) and its derivatives have been reported to possess antiangiogenic effect via electrostatic interaction with various angiogenic growth factors such as VEGF165. However, clinical applications of LMWH for anticancer therapy have been restricted due to its anticoagulant effect and insufficient therapeutic efficacy. To overcome these limitations and enhance the antiangiogenic efficacy, LMWH was conjugated with suramin fragments that have a binding affinity to the heparin-binding domain (HBD) of proteins. The conjugation of suramin fragments to LMWH enhanced the antiangiogenic effect of LMWH by increasing the binding affinity to VEGF165, while decreasing its anticoagulant activity. The chemical conjugate of LMWH and suramin fragments (LHsura) showed a substantial inhibitory effect on VEGF165-mediated cell proliferation, migration, and tube formation of HUVECs without significant cytotoxicity in vitro. Finally, we confirmed the anticancer effect of LHsura (61.4% vs control) in a SCC7-bearing mouse model.