Targeting antigens to dendritic cell receptors for vaccine development

Dendritic cells (DCs) are highly specialized antigen presenting cells of the immune system which play a key role in regulating immune responses. Depending on the method of antigen delivery, DCs stimulate immune responses or induce tolerance. As a consequence of the dual function of DCs, DCs are studied in the context of immunotherapy for both cancer and autoimmune diseases. In vaccine development, a major aim is to induce strong, specific T-cell responses. This is achieved by targeting antigen to cell surface molecules on DCs that efficiently channel the antigen into endocytic compartments for loading onto MHC molecules and stimulation of T-cell responses. The most attractive cell surface receptors, expressed on DCs used as targets for antigen delivery for cancer and other diseases, are discussed

Exploring the interactions of irbesartan and irbesartan–2-hydroxypropyl-β-cyclodextrin complex with model membranes

The interactions of irbesartan (IRB) and irbesartan–2-hydroxypropyl-β-cyclodextrin (HP-β-CD) complex with Dipalmitoyl Phosphatidylcholine (DPPC) bilayers have been explored utilizing an array of biophysical techniques ranging from Differential Scanning Calorimetry (DSC), Small angle X-ray Scattering (SAXS), ESI Mass-Spectrometry (ESI-MS) and solid state Nuclear Magnetic Resonance (ssNMR). Molecular Dynamics (MD) calculations have been also conducted to complement the experimental results. Irbesartan was found to be embedded in the lipid membrane core and to affect the phase transition properties of the DPPC bilayers. SAXS studies revealed that irbesartan alone does not display perfect solvation since some coexisting irbesartan crystallites are present. In its complexed form IRB gets fully solvated in the membranes showing that encapsulation of IRB in HP-β-CD may have beneficial effects in the ADME properties of this drug. MD experiments revealed the topological and orientational integration of irbesartan into the phospholipid bilayer being placed at about 1 nm from the membrane centre

Arginine deprivation alters microglia polarity and synergises with radiation to eradicate non arginine auxotrophic glioblastoma tumors

New approaches for the management of glioblastoma (GBM) are an urgent and unmet clinical need. Here, we illustrate that the efficacy of radiotherapy for GBM is strikingly potentiated by concomitant therapy with the arginine depleting agent ADI-PEG20 in a non-arginine auxotrophic cellular background (Arginine Succinate Synthetase 1 positive). Moreover, this combination led to durable and complete radiological and pathological response with extended disease-free survival in an orthotopic immune competent model of GBM with no significant toxicity. ADI-PEG20 not only enhances the cellular sensitivity of Arginine succinate synthetase 1 positive GBM to ionising radiation by elevated production of nitric oxide (NO) and hence generation of cytotoxic peroxynitrites, but also promotes glioma-associated macrophages/microglia infiltration into tumors and turns their classical anti-inflammatory (pro-tumor) phenotype into a pro-inflammatory (anti-tumor) phenotype. Our results provide an effective, well-tolerated and simple strategy to improve GBM treatment which merits consideration for early evaluation in clinical trials

Molecular Biomechanics: The Molecular Basis of How Forces Regulate Cellular Function

Recent advances have led to the emergence of molecular biomechanics as an essential element of modern biology. These efforts focus on theoretical and experimental studies of the mechanics of proteins and nucleic acids, and the understanding of the molecular mechanisms of stress transmission, mechanosensing and mechanotransduction in living cells. In particular, single-molecule biomechanics studies of proteins and DNA, and mechanochemical coupling in biomolecular motors have demonstrated the critical importance of molecular mechanics as a new frontier in bioengineering and life sciences. To stimulate a more systematic study of the basic issues in molecular biomechanics, and attract a broader range of researchers to enter this emerging field, here we discuss its significance and relevance, describe the important issues to be addressed and the most critical questions to be answered, summarize both experimental and theoretical/computational challenges, and identify some short-term and long-term goals for the field. The needs to train young researchers in molecular biomechanics with a broader knowledge base, and to bridge and integrate molecular, subcellular and cellular level studies of biomechanics are articulated.National Institutes of Health (U.S.) (grant UO1HL80711-05 to GB)National Institutes of Health (U.S.) (grant R01GM076689-01)National Institutes of Health (U.S.) (grant R01AR033236-26)National Institutes of Health (U.S.) (grant R01GM087677-01A1)National Institutes of Health (U.S.) (grant R01AI44902)National Institutes of Health (U.S.) (grant R01AI38282)National Science Foundation (U.S.) (grant CMMI-0645054)National Science Foundation (U.S.) (grant CBET-0829205)National Science Foundation (U.S.) (grant CAREER-0955291

Spin Labeling of Surface Cysteines Using a Bromoacrylaldehyde Spin Label

Structural investigations of proteins and their biological complexes are now frequently complemented by distance constraints between spin labeled cysteines generated using double electron–electron resonance (DEER) spectroscopy, via site directed spin labeling (SDSL). Methanethiosulfonate spin label (MTSSL), has become ubiquitous in the SDSL of proteins, however, has limitations owing to its high number of rotamers, and reducibility. In this article we introduce the use of bromoacrylaldehyde spin label (BASL) as a cysteine spin label, demonstrating an advantage over MTSSL due to its increased selectivity for surface cysteines, eliminating the need to ‘knock out’ superfluous cysteine residues. Applied to the multidomain protein, His domain protein tyrosine phosphatase (HD-PTP), we show that BASL can be easily added in excess with selective labeling, whereas MTSSL causes protein precipitation. Furthermore, using DEER, we were able to measure a single cysteine pair distance in a three cysteine domain within HD-PTP. The label has a further advantage of comprising a sulfide in a three-bond tether, making it a candidate for protein binding and in-cell studies

Encapsulation of temozolomide in a calixarene nanocapsule improves its stability and enhances its therapeutic efficacy against glioblastoma

The alkylating agent temozolomide (TMZ) is the first-line chemotherapeutic for glioblastoma (GBM), a common and aggressive primary brain tumour in adults. However, its poor stability and unfavourable pharmacokinetic profile limit its clinical efficacy. There is an unmet need to tailor the therapeutic window of TMZ, either through complex derivatization or by utilizing pharmaceutical excipients. To enhance stability and aqueous solubility, we encapsulated TMZ in a p-sulphonatocalix[4]arene (Calix) nanocapsule and employed 1H-NMR, LC-MS and UV-Vis spectroscopy to chart the stability of this novel TMZ@Calix complex according to FDA and EMA guidelines. LC-MS/MS plasma stability assays were conducted in mice to further explore the stability profile of TMZ@Calix in vivo. The therapeutic efficacy of TMZ@Calix was compared to that of unbound TMZ in GBM cell lines and patient derived primary cells with known O6-methylguanine-DNA methyltransferase (MGMT) expression status and in vivo in an intracranial U87 xenograft mouse model. Encapsulation significantly enhanced the stability of TMZ in all conditions tested. TMZ@Calix was more potent than native TMZ at inhibiting the growth of established GBM cell lines and patient derived primary lines expressing MGMT and highly resistant to TMZ. In vivo, native TMZ was rapidly degraded in mouse plasma, whereas the stability of TMZ@Calix was enhanced 3-fold with increased therapeutic efficacy in an orthotopic model. In the absence of new effective therapies, this novel formulation is of clinical importance serving as an inexpensive and highly efficient treatment that could be made readily available to GBM patients and warrants further pre-clinical and clinical evaluation

Development of a validated LC-MS/MS method for the in vitro and in vivo quantitation of sunitinib in glioblastoma cells and cancer patients

Sunitinib is a multi-targeted tyrosine kinase inhibitor approved for the treatment of renal cell carcinoma and imatinib-resistant gastrointestinal stromal tumor and is currently being investigated against other forms of malignant tumors. Recently great interest has emerged for the application of sunitinib to glioblastoma treatment. In order to have a method with broad applicability it will be of importance to have access to a method that could be applied both in human plasma and cell uptake studies. No method has been reported thus far for the estimation of sunitinib uptake in glioma cells. We therefore set out to develop a method that could be applied for quantifying sunitinib in human plasma and in cell uptake studies. The method was validated and accredited according to ISO 17025:2005 guideline in human plasma and successfully applied to cancer patient plasma. Also, the method was effectively recruited to establish a protocol for the evaluation of sunitinib accumulation into M095K glioma cells. This method could significantly contribute to developmental phases in repurposing this drug in different cancer types

Splint ligation of RNA with T4 DNA ligase

Splint ligation of RNA, whereby specific RNA molecules are ligated together, can be carried out using T4 DNA ligase and a bridging DNA oligonucleotide complementary to the RNAs. This method takes advantage of the property of T4 DNA ligase to join RNA molecules when they are in an RNA:DNA hybrid. Splint ligation is a useful tool for the introduction of modified nucleotides into RNA molecules, insertion of a radiolabel into a specific position within an RNA and for the assembly of smaller synthetic RNAs into longer RNA molecules. Such modifications enable a wide range of experiments to be carried out with the modified RNA including structural studies, co-immunoprecipitations, and the ability to map sites of RNA:RNA and RNA:protein interactions

Novel imatinib derivatives with altered specificity between Bcr-Abl and FMS, KIT, and PDGF receptors.

Imatinib is a clinically important ATP analogue inhibitor that targets the tyrosine kinase domain of the intracellular Abl kinase and the PDGF receptor family. Imatinib has revolutionised the treatment of chronic myeloid leukaemia, which is caused by the oncogene Bcr-Abl and certain solid tumours that harbor oncogenic mutations of the PDGF receptor family. As a leading kinase inhibitor, imatinib also provides an excellent model system to investigate how changes in drug design impact biological activity, which is an important consideration for rational drug design. Herein we report a new series of imatinib derivatives that in general have greater activity against the family of PDGF receptors and poorer activity against Abl, as a result of modifications of the phenyl and N-methylpiperazine rings. These new compounds provide a platform for further drug development against the therapeutically important PDGF receptor family and they also provide insight into the engineering of drugs with altered biological activity