ARv7 Represses Tumor-Suppressor Genes in Castration-Resistant Prostate Cancer.

Androgen deprivation therapy for prostate cancer (PCa) benefits patients with early disease, but becomes ineffective as PCa progresses to a castration-resistant state (CRPC). Initially CRPC remains dependent on androgen receptor (AR) signaling, often through increased expression of full-length AR (ARfl) or expression of dominantly active splice variants such as ARv7. We show in ARv7-dependent CRPC models that ARv7 binds together with ARfl to repress transcription of a set of growth-suppressive genes. Expression of the ARv7-repressed targets and ARv7 protein expression are negatively correlated and predicts for outcome in PCa patients. Our results provide insights into the role of ARv7 in CRPC and define a set of potential biomarkers for tumors dependent on ARv7.

3D Carbon Scaffolds for Neural Stem Cell Culture and Magnetic Resonance Imaging.

3D glassy carbon structures with percolated macropores are obtained by pyrolysis of chemically synthesized cryogels featuring tunable porosity. These batch-fabricated structures are used as scaffolds for culturing neural stem cells (NSCs) and are characterized by magnetic resonance imaging (MRI). With the aid of MRI, the successful cultivation of NSCs on a glassy carbon surface and the precise 3D locations of these cell clusters within the opaque scaffold are demonstrated. MRI also yields pore morphology and porosity analyses, pre- and post-pyrolysis. This integrated approach yields a complete 3D dataset of the NSC network, which enables the visual inspection of the morphological details of individual cell clusters without disturbing them or destroying the scaffold. Reported experimental methodology is expected to have an impact on studies designed to understand the mechanism of neurodegenerative disease (ND) development, and can serve as a protocol for the culture of various other types of cells that display compatibility with glassy carbon surfaces.

Long-Term Stability of Polymer-Coated Surface Transverse Wave Sensors for the Detection of Organic Solvent Vapors.

Arrays with polymer-coated acoustic sensors, such as surface acoustic wave (SAW) and surface transverse wave (STW) sensors, have successfully been applied for a variety of gas sensing applications. However, the stability of the sensors' polymer coatings over a longer period of use has hardly been investigated. We used an array of eight STW resonator sensors coated with different polymers. This sensor array was used at semi-annual intervals for a three-year period to detect organic solvent vapors of three different chemical classes: a halogenated hydrocarbon (chloroform), an aliphatic hydrocarbon (octane), and an aromatic hydrocarbon (xylene). The sensor signals were evaluated with regard to absolute signal shifts and normalized signal shifts leading to signal patterns characteristic of the respective solvent vapors. No significant time-related changes of sensor signals or signal patterns were observed, i.e., the polymer coatings kept their performance during the course of the study. Therefore, the polymer-coated STW sensors proved to be robust devices which can be used for detecting organic solvent vapors both qualitatively and quantitatively for several years.

Silk scaffolds connected with different naturally occurring biomaterials for prostate cancer cell cultivation in 3D.

In the present work, different biopolymer blend scaffolds based on the silk protein fibroin from Bombyx mori (BM) were prepared via freeze-drying method. The chemical, structural, and mechanical properties of the three dimensional (3D) porous silk fibroin (SF) composite scaffolds of gelatin, collagen, and chitosan as well as SF from Antheraea pernyi (AP) and the recombinant spider silk protein spidroin (SSP1) have been systematically investigated, followed by cell culture experiments with epithelial prostate cancer cells (LNCaP) up to 14 days. Compared to the pure SF scaffold of BM, the blend scaffolds differ in porous morphology, elasticity, swelling behavior, and biochemical composition. The new composite scaffold with SSP1 showed an increased swelling degree and soft tissue like elastic properties. Whereas, in vitro cultivation of LNCaP cells demonstrated an increased growth behavior and spheroid formation within chitosan blended scaffolds based on its remarkable porosity, which supports nutrient supply matrix. Results of this study suggest that silk fibroin matrices are sufficient and certain SF composite scaffolds even improve 3D cell cultivation for prostate cancer research compared to matrices based on pure biomaterials or synthetic polymers.

Superporous Poly(ethylene glycol) Diacrylate Cryogel with a Defined Elastic Modulus for Prostate Cancer Cell Research.

The physical and mechanical properties of the tumor microenvironment are crucial for the growth, differentiation and migration of cancer cells. However, such microenvironment is not found in the geometric constraints of 2D cell culture systems used in many cancer studies. Prostate cancer research, in particular, suffers from the lack of suitable in vitro models. Here a 3D superporous scaffold is described with thick pore walls in a mechanically stable and robust architecture to support prostate tumor growth. This scaffold is generated from the cryogelation of poly(ethylene glycol) diacrylate to produce a defined elastic modulus for prostate tumor growth. Lymph node carcinoma of the prostate (LNCaP) cells show a linear growth over 21 d as multicellular tumor spheroids in such a scaffold with points of attachments to the walls of the scaffold. These LNCaP cells respond to the growth promoting effects of androgens and demonstrate a characteristic cytoplasmic-nuclear translocation of the androgen receptor and androgen-dependent gene expression. Compared to 2D cell culture, the expression or androgen response of prostate cancer specific genes is greatly enhanced in the LNCaP cells in this system. This scaffold is therefore a powerful tool for prostate cancer studies with unique advantages over 2D cell culture systems.

Surface Acoustic Wave (SAW) biosensors: coupling of sensing layers and measurement.

Surface acoustic wave (SAW) devices based on horizontally polarized surface shear waves enable direct and label-free detection of proteins in real time. Signal response changes result mainly from mass increase and viscoelasticity changes on the device surface. With an appropriate sensor configuration all types of binding reactions can be detected by determining resonant frequency changes of an oscillator. To create a biosensor, SAW devices have to be coated with a sensing layer binding specifically to the analyte. Intermediate hydrogel layers used within the coating have been proven to be very suitable to easily immobilize capture molecules or ligands corresponding to the analyte. However, aside from mass increase due to analyte binding, the SAW signal response in a subsequent binding experiment strongly depends on the morphology of the sensing layer, as this may lead to different relative changes of viscoelasticity. Bearing these points in mind, we present two basic biosensor coating procedures, one with immobilized capture molecule and a second with immobilized ligand, allowing reliable SAW biosensor signal responses in subsequent binding assays.

Biosensors for diagnostic applications.

Biosensors combine a transducer with a biorecognition element and thus are able to transform a biochemical event on the transducer surface directly into a measurable signal. By this they have the potential to provide rapid, real-time, and accurate results in a comparatively easy way, which makes them promising analytical devices. Since the first biosensor was introduced in 1962 as an "enzyme electrode" for monitoring glucose in blood, medical applications have been the main driving force for further biosensor development. In this chapter we outline potential biosensor setups, focusing on transduction principles, biorecognition layers, and biosensor test formats, with regard to potential applications. A summary of relevant aspects concerning biosensor integration in efficient analytical setups is included. We describe the latest applications of biosensors in diagnostic applications focusing on detection of molecular biomarkers in real samples. An overview of the current state and future trends of biosensors in this field is given.

Surface modification of an acoustic biosensor allowing the detection of low concentrations of cancer markers.

Analyte detection with biosensors is strongly influenced by the preparation of the biosensor surface including choice of sensing layers and coupling methods for corresponding capture molecules. We investigated the influence of different coupling procedures, especially considering coupling chemistry and incubation times for reagents, by means of surface acoustic wave (SAW) biosensors. The effect on the signal response was tested in two subsequent protein assays. Our optimized coupling procedure allowed the detection of the breast cancer markers HER-2 (human epidermal growth factor receptor-2) and TIMP-1 (tissue inhibitor of metalloproteinase-1) below the respective clinical cutoff values of only a few nanograms per milliliter.

Biosensors with label-free detection designed for diagnostic applications.

Since the first biosensor was introduced in 1962 by Clark and Lyons, there has been increasing demand for such analytical devices in diagnostic applications. Research initially focussed mainly on detector principles and recognition elements, whereas the packaging of the biosensors and the microfluidic integration has been discussed only more recently. However, to obtain a user-friendly and well-performing analytical device, those components have to be considered all together. This review outlines the requirements and the solutions suggested for the integration of suitable biosensors in packaging and the integration of those encapsulated biosensors into a microfluidic surrounding resulting in a complete and efficient analytical device for diagnostic applications. The components required for a complete biosensor instrument are described and the latest developments which meet the requirements for diagnostic applications, such as single-use components and arrays for multiparameter detection, are discussed. The current state and the future of biosensors in the field of clinical diagnostics are outlined, particularly on the basis of label-free assay formats and the detection of prominent biomarkers for cancer and autoimmune disorders.