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

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.

Improved survival rate and minimal side effects of doxorubicin for lung metastasis using engineered discoidal polymeric particles

Despite advances in cancer therapy, the discovery of effective cancer treatments remains challenging. In this study, a simple method was developed to increase the efficiency of doxorubicin (DOX) delivery in a lung metastasis model. This method comprises a simple configuration to increase the delivery efficiency via precise engineering of the size, shape, loading content, and biodegradability of the drug delivery system. This system had a 3 μm discoidal shape and exerted approximately 90% burst release of the drug within the first 24 h. There was no cytotoxicity of the drug carrier up to a concentration of 1 mg ml^-1, and DOX from the carrier was delivered into the cancer cells, exhibiting an anticancer effect comparable to that of the free drug. The ex vivo results revealed a strong correlation between the location of cancer cells in the lung and the location of DOX delivered by this drug delivery system. These drug carriers were confirmed to intensively deliver DOX to cancer cells in the lung, with minimal off-target effects. These findings indicate that this delivery system can be a new approach to improving the survival rate and reducing the side effects caused by anticancer drugs without the use of targeting ligands and polyethylene glycol.

Multiple-therapy strategies via polysaccharides-based nano-systems in fighting cancer

Polysaccharide-based biomaterials (e.g., chitosan, dextran, hyaluronic acid, chondroitin sulfate and heparin) have received great attention in healthcare, particularly in drug delivery for tumor therapy. They are naturally abundant and available, outstandingly biodegradable and biocompatible, and they generally have negligible toxicity and low immunogenicity. In addition, they are easily chemically or physically modified. Therefore, PSs-based nanoparticles (NPs) have been extensively investigated for the enhancement of tumor treatment. In this review, we introduce the synthetic pathways of amphiphilic PS derivatives, which allow the constructs to self-assemble into NPs with various structures. We especially offer an overview of the emerging applications of self-assembled PSs-based NPs in tumor chemotherapy, photothermal therapy (PTT), photodynamic therapy (PDT), gene therapy and immunotherapy. We believe that this review can provide criteria for a rational and molecular level-based design of PS-based NPs, and comprehensive insight into the potential of PS-based NPs used in multiple cancer therapies.

Research progress in the application of bile acid-drug conjugates: A "trojan horse" strategy

Bile acid transporters are highly expressed in intestinal cells and hepatocytes, and they determine the uptake of drugs in cells by modulating cellular entry and exit. In order to improve the oral bioavailability of drugs and investigate the potential application prospects of drugs used to target cancer, numerous studies have adopted these transporters to identify prodrug strategies. Through the connection of covalent bonds between drugs and bile acids, the resulting bile acid-drug conjugates continue to be recognized as similar to natural unmodified bile acid and is translocated by the transporter. The present mini-review provides a brief summary of recent progress of the application of bile acid-drug conjugates based primarily on ASBT, NTCP, and OATP, with the hope of contributing to subsequent research.

Drug delivery carriers with therapeutic functions

Design of micro- or nanocarriers for drug delivery has primarily been focused on properties such as hydrophobicity, biodegradability, size, shape, surface charge, and toxicity, so that they can achieve optimal delivery with respect to drug loading, release kinetics, biodistribution, cellular uptake, and biocompatibility. Incorporation of stimulus-sensitive moieties into the carriers would lead to "smart" delivery systems. A further evolution would be to endow the carrier with a therapeutic function such that it no longer serves as a mere passive entity to release the drug at the target tissue but can be viewed as a therapeutic agent in itself. In this review, we will discuss recent and ongoing efforts over the past decade to design therapeutic drug carriers that confer a biological benefit, including ROS scavenging or generating, pro- or anti-inflammatory, and immuno-evasive properties, to enhance the overall therapeutic efficacy of the delivery systems.

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.

Development of low molecular weight heparin based nanoparticles for metastatic breast cancer therapy

Tumor metastasis is the primary obstacle in cancer treatment and is always the leading cause of human death. And heparin and its derivatives are potential anti-metastatic agents with good biocompatibility. In this work, low molecular weight heparin (LMWH) based LMWH-Cholesterol (LHC) conjugates were prepared for intravenous delivery of doxorubicin (DOX). The DOX/LHC nanoparticles (DOX/LHC NPs) exhibited a spherical shape with a mean diameter of 135.5±2.2nm and had a longer circulation time than that of DOX. The in vitro results confirmed that the DOX/LHC NPs was more effectively taken up by 4T1 cells and showed a stronger anti-metastatic effect by cell invasion and cell migration compared with DOX. Meanwhile, DOX/LHC NPs also exhibited superior anti-metastatic effects in the pulmonary metastasis model compared with other groups. The reason may be account for the synergistic effect between the cytotoxic drug of DOX and its drug carrier of LMWH based nanoparticles, which is capable of anti-metastatic and anti-angiogenic efficiency. Thus DOX/LHC nanoparticles could be a promising anti-metastatic drug delivery system for postoperative chemotherapy.

Improving intestinal absorption and oral bioavailability of curcumin via taurocholic acid-modified nanostructured lipid carriers

The expression of multiple receptors on intestinal epithelial cells enables an actively targeted carrier to significantly enhance the oral delivery of payloads. Conjugating the receptors' ligands on the surfaces of a particulate-delivery system allows site-specific targeting. Here, we used taurocholic acid (TCA) as a ligand for uptake of nanostructured lipid carriers (NLCs) mediated by a bile-acid transporter to improve oral bioavailability of curcumin (Cur). First, synthesis of TCA-polyethylene glycol 100-monostearate (S100-TCA) was carried out. Then, the physical and chemical properties of S100-TCA-modified Cur-loaded NLCs (Cur-TCA NLCs) with varying levels of S100-TCA modifications were investigated. Small particle size (<150 nm), high drug encapsulation (>90%), drug loading (about 3%), negative ζ-potential (-7 to -3 mV), and sustained release were obtained. In situ intestinal perfusion studies demonstrated improved absorption rate and permeability coefficient of Cur-TCA NLCs. Depending on the degree of modification, Cur-TCA NLCs displayed about a five- to 15-fold higher area under the curve in rats after oral administration than unmodified Cur NLCs, which established that the addition of S100-TCA to the NLCs boosted absorption of Cur. Further investigations of TCA NLCs might reveal a bright future for effective oral delivery of poorly bioavailable drugs.

The Interaction of Selectins and PSGL-1 as a Key Component in Thrombus Formation and Cancer Progression

Cellular interaction is inevitable in the pathomechanism of human disease. Formation of heterotypic cellular aggregates, between distinct cells of hematopoietic and nonhematopoietic origin, may be involved in events leading to inflammation and the complex process of cancer progression. Among adhesion receptors, the family of selectins with their ligands have been considered as one of the major contributors to cell-cell interactions. Consequently, the inhibition of the interplay between selectins and their ligands may have potential therapeutic benefits. In this review, we focus on the current evidence on the selectins as crucial modulators of inflammatory, thrombotic, and malignant disorders. Knowing that there is promiscuity in selectin binding, we outline the importance of a key protein that serves as a ligand for all selectins. This dimeric mucin, the P-selectin glycoprotein ligand 1 (PSGL-1), has emerged as a major player in inflammation, thrombus, and cancer development. We discuss the interaction of PSGL-1 with various selectins in physiological and pathological processes with particular emphasis on mechanisms that lead to severe disease.

Engineered Human Ferritin Nanoparticles for Direct Delivery of Tumor Antigens to Lymph Node and Cancer Immunotherapy

Efficient delivery of tumor-specific antigens (TSAs) to lymph nodes (LNs) is essential to eliciting robust immune response for cancer immunotherapy but still remains unsolved. Herein, we evaluated the direct LN-targeting performance of four different protein nanoparticles with different size, shape, and origin [Escherichia coli DNA binding protein (DPS), Thermoplasma acidophilum proteasome (PTS), hepatitis B virus capsid (HBVC), and human ferritin heavy chain (hFTN)] in live mice, using an optical fluorescence imaging system. Based on the imaging results, hFTN that shows rapid LN targeting and prolonged retention in LNs was chosen as a carrier of the model TSA [red fluorescence protein (RFP)], and the flexible surface architecture of hFTN was engineered to densely present RFPs on the hFTN surface through genetic modification of subunit protein of hFTN. The RFP-modified hFTN rapidly targeted LNs, sufficiently exposed RFPs to LN immune cells during prolonged period of retention in LNs, induced strong RFP-specific cytotoxic CD8⁺ T cell response, and notably inhibited RFP-expressing melanoma tumor growth in live mice. This suggests that the strategy using protein nanoparticles as both TSA-carrying scaffold and anti-cancer vaccine holds promise for clinically effective immunotherapy of cancer.

The effect of a tertiary bile acid, taurocholic acid, on the morphology and physical characteristics of microencapsulated probucol: potential applications in diabetes: a characterization study

In recent studies, we designed multi-compartmental microcapsules as a platform for the targeted oral delivery of lipophilic drugs in an animal model of type 2 diabetes (T2D). Probucol (PB) is a highly lipophilic, antihyperlipidemic drug with potential antidiabetic effects. PB has low bioavailability and high inter-individual variations in absorption, which limits its clinical applications. In a new study, the bile acid, taurocholic acid (TCA), exerted permeation enhancing effects in vivo. Accordingly, this study aimed to design and characterize TCA-based PB microcapsules and examine the effects of TCA on the microcapsules' morphology, stability, and release profiles. Microcapsules were prepared using the polymer sodium alginate (SA). Two types of microcapsules were produced, one without TCA (PB-SA, control) and one with TCA (PB-TCA-SA, test). Microcapsules were studied in terms of morphology, surface structure and composition, size, drug contents, cross-sectional imaging (using microtomography (Micro-CT) analysis), Zeta potential, thermal and chemical profiles, rheological parameters, swelling, mechanical strength, and release studies at various temperature and pH values. The production yield and the encapsulation efficiency were also studied together with in vitro efficacy testing of cell viability at various glucose concentrations and insulin and TNF-α production using clonal-mouse pancreatic β-cells. PB-TCA-SA microcapsules showed uniform structure and even distribution of TCA within the microcapsules. Drug contents, Zeta potential, size, rheological parameters, production yield, and the microencapsulation efficiency remained similar after TCA addition. In vitro testing showed PB-TCA-SA microcapsules improved β-cell survival under hyperglycemic states and reduced the pro-inflammatory cytokine TNF-α while increasing insulin secretions compared with PB-SA microcapsules. PB-TCA-SA microcapsules also showed good stability, better mechanical (p < 0.01) and swelling (p < 0.01) characteristics, and optimized controlled release at pH 7.8 (p < 0.01) compared with control, suggesting desirable targeted release properties and potential applications in the oral delivery of PB in T2D.

Modulating the SDF-1/CXCL12-induced cancer cell growth and adhesion by sulfated K5 polysaccharides in vitro

Stromal cell-derived factor-1 (SDF-1)/chemokine (CXC motif) ligand 12 (CXCL12) is involved in the process of tumor progression. Sulfated K5 polysaccharides have shown anti-cancer activity by acting on multiple targets, though it remains unclear whether sulfated K5 polysaccharides would disrupt SDF-1/CXCL12-stimulated cancer biology. This study aimed to investigate the effects of sulfated K5 polysaccharides on cell growth, adhesion in murine B16 melanoma cells and the underlying mechanism by targeting SDF-1/CXCL12. Results indicated that K5-NS,OS inhibited the proliferation of B16 melanoma cells, induced the cell cycle arrest mainly at the G0/G1 phase, and suppressed cancer cell proliferation or adhesion induced by SDF-1/CXCL12. It was possible that K5-NS,OS appeared to interact with CXCL12 and block the subsequent biological functions. This work suggests that the existence of O- and N-sulfate groups is more effective in targeting CXCL12 and exhibiting anti-cancer activity.

A low-molecular-weight heparin-coated doxorubicin-liposome for the prevention of melanoma metastasis

Tumor metastasis is the biggest challenge in cancer therapy. During the metastasis process, metastatic cells could acquire stealth ability toward immune system through the formation of a protection cloak by hijacking platelets (PTs). Heparins, a heterogeneous mixture of glycosaminoglycans, can inhibit metastatic cascades by blocking P-selectin-mediated intercellular adhesion between tumor cells and PTs. In this study, low-molecular-weight heparin-coated doxorubicin-loaded liposome (LMWH-DOX-Lip) was developed for metastasis preventative therapy. The formation of LMWH-DOX-Lip was based on electrostatic interactions between the negatively charged heparins and cationic lipids. LMWH-DOX-Lip prepared at the optimum prescription possessed high entrapment efficiency, ideal particle size and zeta potential. Morphology of LMWH-DOX-Lip was characterized by atomic force microscopy and transmission electron microscopy. The results of confocal microscopic observations and flow cytometry analysis indicated that LMWH-DOX-Lip mediated an efficient cellular uptake in B16F10 melanoma cell line. Besides, LMWH-DOX-Lip displayed an increased cytotoxic over their unmodified counterparts. Furthermore, the inhibition effect of LMWH-DOX-Lip on adhesion between tumor cells and PTs/P-selectin was observed. In vivo study performed on a pulmonary melanoma mouse model revealed a substantially tumor metastasis prevention by LMWH-DOX-Lip. All these results suggested that LMWH-DOX-Lip could significantly inhibit metastasis through preventing the tumor cell-platelet interactions and in the meantime suppressed tumor growth.

Non-invasive optical imaging of cathepsin B with activatable fluorogenic nanoprobes in various metastatic models

An increasing number of treatments of metastases rely on diagnostics and imaging these days. The facts that the activity of cathepsin B (CB) is markedly linked to the metastatic process and that CB is found highly expressed in the pericellular regions in this process make CB an attractive target for diagnosing metastases. We have developed a CB-sensitive nanoprobe (CB-CNP) consisting of self-quenched CB-sensitive fluorogenic peptide probes conjugated onto the surface of tumor-targeting glycol chitosan nanoparticles (CNPs). The freshly prepared CB-CNP formed a spherical nanoparticle structure (280 nm in diameter) and the fluorescence intensity of CB-CNP was strongly quenched in physiological condition. However, self-quenched CB-CNP boosted strong fluorescence signals in the presence of CB, not of cathepsin l or cathepsin d, due to the CB-specific cleavage of self-quenched peptide probes. Importantly, the intravenously injected CB-CNP demonstrated the potential to discriminate metastases in vivo in three metastatic mouse models, including 4T1-luc2 liver metastases, RFP-B16F10 lung metastases and HT1080 peritoneal metastases. Indeed, Western blot analysis confirmed that the CB expression of metastases had increased compared to normal organ in these metastatic mouse models. CB-CNPs may be useful for depicting metastases through non-invasive CB molecular imaging.

Oral delivery of taurocholic acid linked heparin-docetaxel conjugates for cancer therapy

We have synthesized taurocholic acid (TCA) linked heparin-docetaxel (DTX) conjugates for oral delivery of anticancer drug. The ternary biomolecular conjugates formed self-assembly nanoparticles where docetaxel was located inside the core and taurocholic acid was located on the surface of the nanoparticles. The coupled taurocholic acid in the nanoparticles had enhanced oral absorption, presumably through the stimulation of a bile acid transporter of the small intestine. The oral absorption profile demonstrated that the concentration of the conjugates in plasma is about 6 fold higher than heparin alone. An anti-tumor study in MDA-MB231 and KB tumor bearing mice showed significant tumor growth inhibition activity by the ternary biomolecular conjugates. Ki-67 histology study also showed evidence of anticancer activity of the nanoparticles. Finally, noninvasive imaging using a Kodak Molecular Imaging System demonstrated that the nanoparticles were accumulated efficiently in tumors. Thus, this approach for oral delivery using taurocholic acid in the ternary biomolecular conjugates is promising for treatment of various types of cancer.

Recent advances in stealth coating of nanoparticle drug delivery systems

Modifying surfaces of nanoparticles (NPs) with polyethylene glycol (PEG), the so-called PEGylation, is the most commonly used method for reducing premature clearance of NPs from the circulation. However, several reports point out that PEGylation may negatively influence the performance of NPs as a drug carrier. Alternative surface modification strategies, including substitute polymers, conditional removal of PEG, and biomimetic surface modification, may provide solutions for the limitations of PEG.

Real-time and non-invasive optical imaging of tumor-targeting glycol chitosan nanoparticles in various tumor models

Recently, various nanoparticle systems have been developed for tumor-targeted delivery of imaging agents or drugs. However, large amount of them still have insufficient tumor accumulation and this limits their further clinical applications. Moreover, the in vivo characteristics of nanoparticles have been largely unknown, because there are few proper technologies to achieve the direct and non-invasive characterization of nanoparticles in live animals. In this paper, we determined the key factors of nanoparticles for in vivo tumor-targeting using our glycol chitosan nanoparticles (CNPs) which have proved their tumor-targeting ability in many previous papers. For this study, CNPs were labeled with near-infrared fluorescence (NIRF) dye, Cy5.5 for in vivo analysis by non-invasive optical imaging techniques. With these Cy5.5-CNPs, the factors such as in vitro/in vivo stability, deformability, and rapid uptake into target tumor cells and their effects on in vivo tumor-targeting were evaluated in various tumor-bearing mice models. In flank tumor models, Cy5.5-CNPs were selectively localized in tumor tissue than other organs, and the real-time intravascular tracking of CNPs proved the enhanced permeation and retention (EPR) effect of nanoparticles in tumor vasculature. Importantly, tumor-targeting CNPs showed an excellent tumor-specificity in brain tumors, liver tumors, and metastasis tumor models, indicating their great potential in both cancer imaging and therapy.

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.

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.