Bakheet Elsadek

Impact of albumin on drug delivery — New applications on the horizon☆☆☆

Over the past decades, albumin has emerged as a versatile carrier for therapeutic and diagnostic agents, primarily for diagnosing and treating diabetes, cancer, rheumatoid arthritis and infectious diseases. Market approved products include fatty acid derivatives of human insulin or the glucagon-like-1 peptide (Levemir(®) and Victoza(®)) for treating diabetes, the taxol albumin nanoparticle Abraxane(®) for treating metastatic breast cancer which is also under clinical investigation in further tumor indications, and (99m)Tc-aggregated albumin (Nanocoll(®) and Albures(®)) for diagnosing cancer and rheumatoid arthritis as well as for lymphoscintigraphy. In addition, an increasing number of albumin-based or albumin-binding drugs are in clinical trials such as antibody fusion proteins (MM-111) for treating HER2/neu positive breast cancer (phase I), a camelid albumin-binding nanobody anti-HSA-anti-TNF-α (ATN-103) in phase II studies for treating rheumatoid arthritis, an antidiabetic Exendin-4 analog bound to recombinant human albumin (phase I/II), a fluorescein-labeled albumin conjugate (AFL)-human serum albumin for visualizing the malignant borders of brain tumors for improved surgical resection, and finally an albumin-binding prodrug of doxorubicin (INNO-206) entering phase II studies against sarcoma and gastric cancer. In the preclinical setting, novel approaches include attaching peptides with high-affinity for albumin to antibody fragments, the exploitation of albumin-binding gadolinium contrast agents for magnetic resonance imaging, and physical or covalent attachment of antiviral, antibacterial, and anticancer drugs to albumin that are permanently or transiently attached to human serum albumin (HSA) or act as albumin-binding prodrugs. This review gives an overview of the expanding field of preclinical and clinical drug applications and developments that use albumin as a protein carrier to improve the pharmacokinetic profile of the drug or to target the drug to the pathogenic site addressing diseases with unmet medical needs.

Clinical impact of serum proteins on drug delivery.

Among serum proteins albumin and transferrin have attracted the most interest as drug carriers in the past two decades. Prior to that, their potential use was overshadowed by the advent of monoclonal antibodies that was initiated by Milstein and Koehler in 1975. Meanwhile intensive pursuit of exploiting transferrin, but above all albumin as an exogenous or endogenous carrier protein for treating various diseases, primarily cancer, rheumatoid arthritis, diabetes and hepatitis has resulted in several marketed products and numerous clinical trials. While the use of transferrin has clinically been primarily restricted to immunotoxins, albumin-based drug delivery systems ranging from albumin drug nanoparticles, albumin fusion protein, prodrugs and peptide derivatives that bind covalently to albumin as well as physically binding antibody fragments and therapeutically active peptides are in advanced clinical trials or approved products. For treating diabetes, Levemir and Victoza that are myristic acid derivatives of human insulin or glucagon-like peptide 1 (GLP-1) act as long-acting peptides by binding to the fatty acid binding sites on circulating albumin to control glucose levels. Levemir from Novo Nordisk has already developed into a blockbuster since its market approval in 2004. Abraxane, an albumin paclitaxel nanoparticle as a water-soluble galenic formulation avoiding the use of cremophor/ethanol, transports paclitaxel through passive targeting as an albumin paclitaxel complex to the tumor site and is superior to conventional Taxol against metastatic breast cancer. INNO-206, an albumin-binding doxorubicin prodrug that also accumulates in solid tumors due to the enhanced permeability and retention (EPR) effect but releases the parent drug through acid cleavage, either intra- or extracellularly, is entering phase II studies against sarcoma. An expanding field is the use of albumin-binding antibody moieties which do not contain the fragment crystallizable (Fc) portion of, conventional immunoglobulin G (IgG) but are comprised of monovalent or bivalent light and/or heavy chains and incorporate an additional albumin-binding peptide or antibody domain. The most advanced antibody of this kind is ATN-103 (Ozoralizumab), a trivalent albumin-binding nanobody that neutralizes the pro-inflammatory tumor necrosis factor alpha (TNF-α) as a causative agent for exacerbating rheumatoid arthritis. ATN-103 is currently in multi-center phase II trials against this debilitating disease. In summary, because albumin as the most abundant circulating protein cannot only be used to improve the pharmacokinetic profile of therapeutically relevant peptides and the targeting moiety of antibodies but also for peptide-based targeting as well as low-molecular weight drugs to inflamed or malignant tissue, it is anticipated that R&D efforts of academia and the pharmaceutical industry in this field of drug delivery will prosper.

In vivo evaluation of a novel albumin-binding prodrug of doxorubicin in an orthotopic mouse model of prostate cancer (LNCaP).

PSA, which is overexpressed in prostate carcinoma, represents a molecular target for selectively releasing an anticancer agent from a prodrug formulation. In this study, we report on the in vivo antitumor efficacy of an efficacious albumin-binding prodrug of doxorubicin (PSA9) that incorporates p-aminobenzyloxycarbonyl (PABC) as a self-immolative spacer in addition to the heptapeptide, Arg-Ser-Ser-Tyr-Tyr-Ser-Leu, which serves as a substrate for PSA. The prodrug is cleaved very efficiently by PSA releasing H-Ser-Leu-PABC-doxorubicin and subsequently doxorubicin in PSA-positive cell lysates and prostate tumor homogenates as the final cleavage product. PSA9 at 3 × 6 mg kg−1 doxorubicin equivalents (intravenous) was compared with conventional doxorubicin at equitoxic doses (at 3 × 3 mg kg−1; intravenous) in an orthotopic mouse model of prostate cancer using LNCaP lentiviral luciferase-neomycin cells transduced with luciferase. Whereas doxorubicin did not show any efficacy against the primary tumor or metastases, the prodrug reduced the primary tumor by 30–50% and circulating PSA levels, and in addition, showed a pronounced reduction in lung and bone metastases by ∼77% and ∼96%, respectively, and a positive trend regarding the activity against liver and lymph-node metastases compared with control and doxorubicin-treated animals. The incorporation of PABC as a self-immolative spacer together with a PSA substrate demonstrates superior antitumor effects over doxorubicin attributed to an efficient cleavage by PSA releasing doxorubicin as the final active agent in prostate tumor homogenates. Using this approach for developing effective prodrugs against prostate cancer, is worthy of further preclinical optimization.

Zinc oxide nanoparticles as a novel anticancer approach; in vitro and in vivo evidences

Currently, the outcomes of conventional chemotherapeutic approaches are unsatisfactory. Clinical application of nanoparticles seems promising. We aim to evaluate the possible antitumor activity of zinc oxide nanoparticles (ZnONPs) as a chemotherapeutic approach in in vitro and in vivo experimental models. An in vitro study was performed on three different cell lines, namely human hepatocellular carcinoma (HEPG2), human prostate cancer (PC3), and none‐small cell lung cancer (A549) cell lines. An in vivo study using diethylnitrosamine (DENA)‐induced HCC in adult male Wistar rats was conducted to investigate the potential antitumor activity of ZnONPs in HCC and the possible underlying mechanisms. Hepatocellular carcinoma (HCC) was induced by oral administration of DENA given in drinking water (100 mg/L) for 8 weeks. Rats were allocated into four groups, namely a control group, an HCC control group receiving DENA alone, a ZnONPs (10 μg/kg per week, intravenous (i.v.) for 1 month) control group, and a ZnONPs treatment group (receiving ZnONPs + DENA). ZnONPs significantly reduced the elevated serum levels of HCC‐related tumor markers alphafetoprotein and alpha‐l‐fucosidase and the apoptotic marker caspase‐3 compared with the untreated HCC rats. In addition, treatment with ZnONPs significantly decreased the elevated levels of hepatocyte integrity and oxidative stress markers as compared with the untreated HCC control group. Furthermore, the histopathological study revealed anaplasia and fibrous degenerations which were significantly corrected by ZnONPs treatment. In conclusion, administration of ZnONPs exhibited a promising preclinical anticancer efficacy in HCC and could be considered as a novel strategy for the treatment HCC in clinical practices.

Implication of Umbilical Cord in Preeclampsia

Objectives: To investigate the role of biochemical changes in the umbilical cord and placenta in developing preeclampsia (PE). Subjects and Methods: Thirty women with PE and 15 healthy pregnant women as controls were enrolled in this study. Vascular endothelial growth factor (VEGF), soluble vascular endothelial growth factor receptor 1 (sVEGFR-1), platelet-derived endothelial cell growth factor (PD-ECGF), neutrophil elastase and nitric oxide (NO) were measured. Results: Both serum (maternal and fetal) and tissue (placenta and umbilical cord) levels of VEGF, sVEGFR-1, PD-ECGF and neutrophil elastase were significantly increased, whereas NO was significantly decreased (except placental tissue showed no changes) in preeclamptic patients. The cord serum level of PD-ECGF was significantly higher in severe PE compared to mild PE and normal pregnant women. The placental and cord tissue levels of PD-ECGF and neutrophil elastase were significantly higher in severe PE, while the cord tissue level of NO was significantly lower in severe PE. Conclusion: Our data showed that umbilical cord vessels and stroma can serve as an additional source of vasoactive and angiogenic substances that contribute to the biochemical changes occurring in PE.

Survivin as a Novel Biomarker in the Pathogenesis of Acne Vulgaris and Its Correlation to Insulin-Like Growth Factor-I

Survivin, a member of the inhibitor of apoptosis protein family, has an important role in cell cycle regulation. Insulin-like growth factor-I (IGF-I) is a polypeptide hormone with wide range of biologic effects including stimulation of lipogenesis in sebaceous glands. Their overexpression in some fibrotic disorders suggests a possible implication of both IGF-I and survivin in the pathogenesis of acne and/or acne scars. The current study aimed to assess and correlate serum levels of IGF-I and survivin in patients with active acne vulgaris and postinflammatory acne scars and to evaluate their lesional expressions in comparison to healthy controls. Serum IGF-I and survivin were estimated using commercially available ELISA kits and their tissues expressions were investigated using Western blotting. Our findings suggest that IGF-I and survivin could play potential roles in the pathogenesis of active acne vulgaris and more importantly in postinflammatory acne scars with significant positive correlation coefficient between serum levels of IGF-I and survivin which support IGF-I-/PI3K-/AKT-mediated downregulation of nuclear expression of FoxO transcription factors resulting in enhanced survivin expression.

The antitumor activity of a lactosaminated albumin conjugate of doxorubicin in a chemically induced hepatocellular carcinoma rat model compared to sorafenib

BACKGROUND Worldwide, consistent survival benefit for chemotherapy in hepatocellular carcinoma (HCC) is a golden goal for concerned researchers. Nexavar® (sorafenib) is the only approved agent that achieved touchable successes in this regard. Thus, there is a pressing medical need for new promising drugs to improve HCC therapy. AIMS our designed lactosaminated albumin conjugate of doxorubicin (L-HSA-DOXO) that rapidly and preferentially accumulates in the liver is compared, for the first time at its MTD, with doxorubicin and sorafenib, not only for antitumor efficacy but also for overall survival. METHODS HCC was induced in male Wistar rats with N-nitrosodiethylamine added to drinking water (100mg/L) for 8 weeks. Endpoints were antitumor efficacy, tolerability and overall survival. RESULTS L-HSA-DOXO proved to be superior at least over doxorubicin in the majority of assessed endpoints. Circulating AFP-L3% was diminished in L-HSA-DOXO (14.5%) and sorafenib (18.4%) groups compared to DENA (31.1%) and doxorubicin (29.5%) groups. This superiority was further confirmed by Western blot analyses of some novel HCC biomarkers. Survival study reinforced consistent benefits of both L-HSA-DOXO and sorafenib. CONCLUSIONS L-HSA-DOXO shows at least comparable activity to sorafenib which clinically achieves only ∼3 months overall survival benefit. Combination of these two agents could act beneficially or synergistically via two different modes of action to fight HCC.

A Novel Model of Cancer-Induced Peripheral Neuropathy and the Role of TRPA1 in Pain Transduction

Background Models of cancer-induced neuropathy are designed by injecting cancer cells near the peripheral nerves. The interference of tissue-resident immune cells does not allow a direct contact with nerve fibres which affects the tumor microenvironment and the invasion process. Methods Anaplastic tumor-1 (AT-1) cells were inoculated within the sciatic nerves (SNs) of male Copenhagen rats. Lumbar dorsal root ganglia (DRGs) and the SNs were collected on days 3, 7, 14, and 21. SN tissues were examined for morphological changes and DRG tissues for immunofluorescence, electrophoretic tendency, and mRNA quantification. Hypersensitivities to cold, mechanical, and thermal stimuli were determined. HC-030031, a selective TRPA1 antagonist, was used to treat cold allodynia. Results Nociception thresholds were identified on day 6. Immunofluorescent micrographs showed overexpression of TRPA1 on days 7 and 14 and of CGRP on day 14 until day 21. Both TRPA1 and CGRP were coexpressed on the same cells. Immunoblots exhibited an increase in TRPA1 expression on day 14. TRPA1 mRNA underwent an increase on day 7 (normalized to 18S). Injection of HC-030031 transiently reversed the cold allodynia. Conclusion A novel and a promising model of cancer-induced neuropathy was established, and the role of TRPA1 and CGRP in pain transduction was examined.

Sequential analysis and staging of a diethylnitrosamine-induced hepatocellular carcinoma in male Wistar albino rat model

Hepatocellular carcinoma (HCC) is one of the most life-threatening cancers. The present study was designed to chronologically analyze the HCC chemically induced by diethylnitrosamine (DEN) in male Wistar rats during a 27-week period. DEN was given to rats in drinking water (100 mg/L) to induce HCC. In the present study, the DEN-administered groups recorded dramatic results in the tumor markers, oxidative stress, lipid profile, liver function, and hematological parameters at all intervals when compared with their corresponding values in the control groups. In addition, the morphometric analysis of livers of the DEN-administered groups (from 9 to 27 weeks) showed gradual enlargement and several grayish white nodules and foci on the peripheral surface of the liver as the features of HCC. In conclusion, the present sequential model chronologically analyzes all steps of hepatocarcinogenesis and presents a new staging system for classification of HCC that may be valuable for investigating the effects of anticarcinogenic compounds at varying stages of hepatocarcinogenesis in vivo.

Expression profiles of TRPV1, TRPV4, TLR4 and ERK1/2 in the dorsal root ganglionic neurons of a cancer-induced neuropathy rat model

Background The spread of tumors through neural routes is common in several types of cancer in which patients suffer from a moderate-to-severe neuropathy, neural damage and a distorted quality of life. Here we aim to examine the expression profiles of transient receptor potential vanilloid 1 (TRPV1) and of transient receptor potential vanilloid 4 (TRPV4), toll-like receptor 4 (TLR4) and extracellular signal-regulated kinase (ERK1/2), and to assess the possible therapeutic strategies through blockade of transient receptor potential (TRP) channels. Methods Cancer was induced within the sciatic nerves of male Copenhagen rats, and tissues from dorsal root ganglia (DRG) were collected and used for measurements of immunofluorescence and Western blotting. The TRPV1 antagonist capsazepine, the selective TRPV4 antagonist HC-067047 and the calcium ions inhibitor ruthenium red were used to treat thermal and/or mechanical hyperalgesia. Results Transient receptor potential vanilloid 1 showed a lower expression in DRGs on days 7 and 14. The expression of TRPV4, TLR4 and ERK1/2 showed an increase on day 3 then a decrease on days 7 and 14. TRPV1 and TLR4 as well as TRPV4 and ERK1/2 co-existed on the same neuronal cells. The neuropathic pain was reversed in dose-dependent manners by using the TRP antagonists and the calcium ions inhibitor. Conclusion The decreased expression of TRPV1 and TRPV4 is associated with high activation. The increased expression of TLR4 and ERK1/2 reveals earlier immune response and tumor progression, respectively, and their ultimate decrease is an indicator of nerve damage. We studied the possible role of TRPV1 and TRPV4 in transducing cancer-induced hyperalgesia. The possible treatment strategies of cancer-induced thermal and/or mechanical hyperalgesia using capsazepine, HC-067047 and ruthenium red are examined.