Optimisation of Folate-Mediated Liposomal Encapsulated Arsenic Trioxide for Treating HPV-Positive Cervical Cancer Cells In Vitro.

High-risk human papilloma virus (HPV) infection is directly associated with cervical cancer development. Arsenic trioxide (ATO), despite inducing apoptosis in HPV-infected cervical cancer cells in vitro, has been compromised by toxicity and poor pharmacokinetics in clinical trials. Therefore, to improve ATO's therapeutic profile for HPV-related cancers, this study aims to explore the effects of length of ligand spacers of folate-targeted liposomes on the efficiency of ATO delivery to HPV-infected cells. Fluorescent ATO encapsulated liposomes with folic acid (FA) conjugated to two different PEG lengths (2000 Da and 5000 Da) were synthesised, and their cellular uptake was examined for HPV-positive HeLa and KB and HPV-negative HT-3 cells using confocal microscopy, flow cytometry, and spectrophotometer readings. Cellular arsenic quantification and anti-tumour efficacy was evaluated through inductively coupled plasma-mass spectrometry (ICP-MS) and cytotoxicity studies, respectively. Results showed that liposomes with a longer folic acid-polyethylene glycol (FA-PEG) spacer (5000 Da) displayed a higher efficiency in targeting folate receptor (FR) + HPV-infected cells without increasing any inherent cytotoxicity. Targeted liposomally delivered ATO also displayed superior selectivity and efficiency in inducing higher cell apoptosis in HPV-positive cells per unit of arsenic taken up than free ATO, in contrast to HT-3. These findings may hold promise in improving the management of HPV-associated cancers.

Effective Delivery of Arsenic Trioxide to HPV-Positive Cervical Cancer Cells Using Optimised Liposomes: A Size and Charge Study.

Despite the success of arsenic trioxide (ATO) in treating haematological malignancies, its potential to treat solid tumours has not been fully exploited, owing to its dose-limiting toxicity and poor pharmacokinetics. In order to overcome this hurdle, liposomal encapsulation of the drug with different surface charges (neutral, negative, and positive) and sizes (100, 200 and 400 nm) were synthesised and tested on human papilloma virus (HPV)-positive HeLa and HPV-negative HT-3 cervical cancer cell lines. Two epithelial cell lines-human keratinocytes (HK) and human colon cells (CRL-1790)-were used as controls. The synthesised liposomes were tested for their physico-chemical characteristics, drug loading efficiency, and toxicity on the studied cell lines. Neutral liposomes of 100 nm in size were the chosen formulation for delivering ATO into the studied cells, as they showed the least intrinsic cytotoxicity and the highest loading efficiency. The findings demonstrated that the optimised formulation of liposomes was an effective drug delivery method for HPV-infected cervical cancer cells. Furthermore, the toxicity vs. uptake ratio was highest for HeLa cells, while a reduced or minimal toxic effect was observed for non-HPV-infected cervical cancer cells and control cells. These findings may provide a promising therapeutic strategy for effectively managing cervical cancers.

Shared features in ear and kidney development - implications for oto-renal syndromes.

The association between ear and kidney anomalies has long been recognized. However, little is known about the underlying mechanisms. In the last two decades, embryonic development of the inner ear and kidney has been studied extensively. Here, we describe the developmental pathways shared between both organs with particular emphasis on the genes that regulate signalling cross talk and the specification of progenitor cells and specialised cell types. We relate this to the clinical features of oto-renal syndromes and explore links to developmental mechanisms.

Liposome­delivered baicalein induction of myeloid leukemia K562 cell death via reactive oxygen species generation.

Baicalein (BL), a potential cancer chemopreventative flavone, has been reported to inhibit cancer cell growth by inducing apoptosis and causing cell cycle arrest in various human cancer cell models. Delivery of BL via nanoliposomes has been shown to improve its oral bioavailability and long­circulating property in vivo. However, the role of BL in the inhibition of human chronic myeloid leukemia (CML) K562 cell growth and its underlying mechanisms has yet to be elucidated. In the present study, BL was formulated into liposomes with different sizes to improve its solubility and stability. The cytotoxic and pro­apoptotic effects of free BL and liposomal BL were also evaluated. The results demonstrated that 100 nm liposomes were the most stable formulation when compared with 200 and 400 nm liposomes. Liposomal BL inhibited K562 cell growth as efficiently as free BL (prepared in DMSO), indicating that the liposome may be a potential vehicle to deliver BL for the treatment of CML. Flow cytometry analysis showed that there was significant (P<0.005) cell cycle arrest in the sub­G1 phase (compared with vehicle control), indicating cell apoptosis following 20 µM liposomal BL or free BL treatment of K562 cells for 48 h. The induction of cell apoptosis by all BL preparations was further confirmed through the staining of treated cells with Annexin V­fluorescein isothiocyanate/propidium iodide. A significant increase in reactive oxygen species (ROS) gene-ration was observed in free BL and liposomal BL treated cells, with a higher level of ROS produced from those treated with free BL. This indicated that cell apoptosis induced by BL may be via ROS generation and liposome delivery may further extend the effect through its long­circulating property.

Emerging applications of nanotechnology for diagnosis and therapy of disease: a review.

Nanotechnology is of increasing interest in the fields of medicine and physiology over recent years. Its application could considerably improve disease detection and therapy, and although the potential is considerable, there are still many challenges that need to be addressed before it is accepted in routine clinical use. This review focuses on emerging applications that nanotechnology could enhance or provide new approaches in diagnoses and therapy. The main focus of recent research centres on targeted therapies and enhancing imaging; however, the introduction of nanomaterial into the human body must be controlled, as there are many issues with possible toxicity and long-term effects. Despite these issues, the potential for nanotechnology to provide new methods of combating cancer and other disease conditions is considerable. There are still key challenges for researchers in this field, including the means of delivery and targeting in the body to provide effective treatment for specific disease conditions. Nanoparticles are difficult to measure due to their size and physical properties; hence there is still a great need to improve physiological measurement methods in the field to ascertain how effective their use is in the human subject. This review is a brief snapshot into the fast changing research field of measurement and physiological links to nanoparticle use and its potential in the future.

Detection of the tau protein in human serum by a sensitive four-electrode electrochemical biosensor.

This study presents a novel approach based on a four-electrode electrochemical biosensor for the detection of tau protein - one of the possible markers for the prediction of Alzheimer's disease (AD). The biosensor is based on the formation of stable antibody-antigen complexes on gold microband electrodes covered with a layer of a self-assembled monolayer and protein G. Antibodies were immobilized on the gold electrode surface in an optimal orientation by protein G interaction. Electrochemical impedance spectroscopy was used to analyze impedance change, which revealed a linear response with increasing tau concentrations. The assay is fast (<1h for incubation and measurement) and very sensitive. The limit of quantification for the full-length 2N4R tau protein is 0.03pM, a value unaltered when the assay was processed in bovine serum albumin or human serum. This technology could be adapted for the detection of other biomarkers to provide a multiple assay to identify AD progression in a point of care setting.

Inhibition of HIV Virus by Neutralizing Vhh Attached to Dual Functional Liposomes Encapsulating Dapivirine.

Although highly active antiretroviral therapy (HAART) has greatly improved the life expectancy of HIV/AIDS patients, the treatment is not curative. It is a global challenge which fosters an urgent need to develop an effective drug or neutralizing antibody delivery approach for the prevention and treatment of this disease. Due to the low density of envelope spikes with restricted mobility present on the surface of HIV virus, which limit the antibody potency and allow virus mutation and escape from the immune system, it is important for a neutralizing antibody to form bivalent or multivalent bonds with the virus. Liposome constructs could fulfil this need due to the flexible mobility of the membrane with its attached antibodies and the capacity for drug encapsulation. In this study, we evaluated the neutralization activity of a range of liposome formulations in different sizes coated with anti-gp120 llama antibody fragments (Vhhs) conjugated via either non-covalent metal chelation or a covalent linkage. The non-covalent construct demonstrated identical binding affinity to HIV-1 envelope glycoprotein gp120 and neutralizing ability for HIV virus as free Vhh. Although covalently linked Vhh showed significant binding affinity to gp120, it unexpectedly had a lower neutralization potency. This may be due to the comparability in size of the viral and liposome particles restricting the number which can be bound to the liposome surface so involving only a fraction of the antibodies, whereas non-covalently attached antibodies dissociate from the surface after acting with gp120 and free the remainder to bind further viruses. Covalently conjugated Vhh might also trigger the cellular uptake of a liposome-virion complex. To explore the possible ability of the antibody-coated liposomes to have a further function, we encapsulated the hydrophobic antiviral drug dapivirine into both of the non-covalently and covalently conjugated liposome formulations, both of which revealed high efficacy in reducing viral replication in vitro. Thus, dual function liposomes may lead to a novel strategy for the prophylaxis of HIV/AIDS by combining the neutralizing activity of Vhh with antiviral effects of high drug concentrations.