Prostate Cancer Metastatic to Bone has Higher Expression of the Calcium-Sensing Receptor (CaSR) than Primary Prostate Cancer

The calcium-sensing receptor (CaSR) is the principal regulator of the secretion of parathyroid hormone and plays key roles in extracellular calcium (Ca2+o) homeostasis. It is also thought to participate in the development of cancer, especially bony metastases of breast and prostate cancer. However, the expression of CaSR has not been systematically analyzed in prostate cancer from patients with or without bony metastases. By comparing human prostate cancer tissue sections in microarrays, we found that the CaSR was expressed in both normal prostate and primary prostate cancer as assessed by immunohistochemistry (IHC). We used two methods to analyze the expression level of CaSR. One was the pathological score read by a pathologist, the other was the positivity% obtained from the Aperio positive pixel count algorithm. Both of the methods gave consistent results. Metastatic prostate cancer tissue obtained from bone had higher CaSR expression than primary prostate cancer (P0.05). The expression of CaSR in cancer tissue was not associated with the stage or status of differentiation of the cancer. These results suggest that CaSR may have a role in promoting bony metastasis of prostate cancer, hence raising the possibility of reducing the risk of such metastases with CaSR-based therapeutics

On Determining Dead Layer and Detector Thicknesses for a Position-Sensitive Silicon Detector

In this work, two particular properties of the position-sensitive, thick silicon detectors (known as the "E" detectors) in the High Resolution Array (HiRA) are investigated: the thickness of the dead layer on the front of the detector, and the overall thickness of the detector itself. The dead layer thickness for each E detector in HiRA is extracted using a measurement of alpha particles emitted from a $^{212}$Pb pin source placed close to the detector surface. This procedure also allows for energy calibrations of the E detectors, which are otherwise inaccessible for alpha source calibration as each one is sandwiched between two other detectors. The E detector thickness is obtained from a combination of elastically scattered protons and an energy-loss calculation method. Results from these analyses agree with values provided by the manufacturer.Comment: Accepted for publication in Nuclear Instruments and Methods in Physics Researc

Paclitaxel (Taxol)-induced Gene Expression and Cell Death Are Both Mediated by the Activation of c-Jun NH 2 -terminal Kinase (JNK/SAPK)

Paclitaxel (Taxol) is a novel anti-cancer drug that has shown efficacy toward several malignant tumors, particularly ovarian tumors. We reported previously that paclitaxel can induce interleukin (IL)-8 promoter activation in subgroups of ovarian cancer through the activation of both AP-1 and nuclear factor kappaB. Further analysis of paclitaxel analogs indicates that the degree of IL-8 induction by analysis correlates with the extent of cell death; however, IL-8 itself is not the cause of cell death. This suggests that pathways that lead to IL-8 and cell death may overlap, although IL-8 per se does not kill tumor cells. To decipher the upstream signals for paclitaxel-induced transcriptional activation and cell death, we studied the involvement of protein kinases that lead to the activation of AP-1, specifically the c-Jun NH2-terminal kinase (JNK1), p38, and the extracellular signal-regulated kinase 1 (ERK1). The role of IkappaB in paclitaxel-induced cell death was also analyzed. Paclitaxel activated JNK, and to a lesser degree p38, but not ERK1. Paclitaxel-induced IL-8 promoter activation was inhibited by dominant-inhibitory mutants of JNK, p38, and the super-repressor form of IkappaBalpha, but not by dominant-inhibitory forms of ERK1. Dominant-inhibitory mutants of JNK1 also greatly reduced paclitaxel-induced cell death, and the kinetics of JNK induction was closely followed by DNA fragmentation. These results indicate (i) that paclitaxel activates the JNK signaling pathway and (ii) that JNK activation is a common point of paclitaxel-induced gene induction and cell death

Absolut “copper catalyzation perfected”; robust living polymerization of NIPAM : Guinness is good for SET-LRP

The controlled polymerization of N-isopropyl acrylamide (NIPAM) is reported in a range of international beers, wine, ciders and spirits utilizing Cu(0)-mediated living radical polymerization (SET-LRP). Highly active Cu(0) is first formed in situ by the rapid disproportionation of [Cu(I)(Me6-Tren)Br] in the commercial water–alcohol mixtures. Rapid, yet highly controlled, radical polymerization follows (Đ values as low as 1.05) despite the numerous chemicals of diverse functionality present in these solvents e.g. alpha acids, sugars, phenols, terpenoids, flavonoids, tannins, metallo-complexes, anethole etc. The results herein demonstrate the robust nature of the aqueous SET-LRP protocol, underlining its ability to operate efficiently in a wide range of complex chemical environments

Inverse tuning of metal binding affinity and protein stability by altering charged coordination residues in designed calcium binding proteins

Ca2+ binding proteins are essential for regulating the role of Ca2+ in cell signaling and maintaining Ca2+ homeostasis. Negatively charged residues such as Asp and Glu are often found in Ca2+ binding proteins and are known to influence Ca2+ binding affinity and protein stability. In this paper, we report a systematic investigation of the role of local charge number and type of coordination residues in Ca2+ binding and protein stability using de novo designed Ca2+ binding proteins. The approach of de novo design was chosen to avoid the complications of cooperative binding and Ca2+-induced conformational change associated with natural proteins. We show that when the number of negatively charged coordination residues increased from 2 to 5 in a relatively restricted Ca2+-binding site, Ca2+ binding affinities increased by more than 3 orders of magnitude and metal selectivity for trivalent Ln3+ over divalent Ca2+ increased by more than 100-fold. Additionally, the thermal transition temperatures of the apo forms of the designed proteins decreased due to charge repulsion at the Ca2+ binding pocket. The thermal stability of the proteins was regained upon Ca2+ and Ln3+ binding to the designed Ca2+ binding pocket. We therefore observe a striking tradeoff between Ca2+/Ln3+ affinity and protein stability when the net charge of the coordination residues is varied. Our study has strong implications for understanding and predicting Ca2+-conferred thermal stabilization of natural Ca2+ binding proteins as well as for designing novel metalloproteins with tunable Ca2+ and Ln3+ binding affinity and selectivity

The role of hole transport between dyes in solid-state dye-sensitized solar cells

In dye-sensitized solar cells (DSSCs) photogenerated positive charges are normally considered to be carried away from the dyes by a separate phase of hole-transporting material (HTM). We show that there can also be significant transport within the dye monolayer itself before the hole reaches the HTM. We quantify the fraction of dye regeneration in solid-state DSSCs that can be attributed to this process. By using cyclic voltammetry and transient anisotropy spectroscopy, we demonstrate that the rate of interdye hole transport is prevented both on micrometer and nanometer length scales by reducing the dye loading on the TiO₂ surface. The dye regeneration yield is quantified for films with high and low dye loadings (with and without hole percolation in the dye monolayer) infiltrated with varying levels of HTM. Interdye hole transport can account for >50% of the overall dye regeneration with low HTM pore filling. This is reduced to about 5% when the infiltration of the HTM in the pores is optimized in 2 μm thick films. Finally, we use hole transport in the dye monolayer to characterize the spatial distribution of the HTM phase in the pores of the dyed mesoporous TiO₂

Extracellular Calcium Modulates Actions of Orthosteric and Allosteric Ligands on Metabotropic Glutamate Receptor 1alpha

SUMMARY: Metabotropic glutamate receptor 1α (mGluR1α), a member of the family C G protein-coupled receptors (GPCRs), is emerging as a potential drug target for various disorders including chronic neuronal degenerative diseases. In addition to being activated by glutamate, mGluR1α is also modulated by extracellular Ca2+. However, the underlying mechanism is unknown. Moreover, it has long been challenging to develop receptor-specific agonists due to homologies within the mGluR family, and the Ca2+-binding site(s) on mGluR1α may provide an opportunity for receptor-selective targeting by therapeutics. In the present study, we show that our previously predicted Ca2+-binding site in the hinge region of mGluR1α is adjacent to the site where orthosteric agonists and antagonists bind on the extracellular domain of the receptor. Moreover, we have found that extracellular Ca2+ enhances mGluR1α-mediated intracellular Ca2+ responses evoked by the orthosteric agonist, L-quisqualate. Conversely, extracellular Ca2+ diminishes the inhibitory effect of the mGluR1α orthosteric antagonist, (s)-MCPG. In addition, selective positive (Ro 67-4853) and negative (CPCCOEt) allosteric modulators of mGluR1α potentiate and inhibit responses to extracellular Ca2+, respectively, in a manner similar to their effects on the response of mGluR1α to glutamate. Mutations at residues predicted to be involved in Ca2+-binding, including E325I, have significant effects on the modulation of responses to the orthosteric agonist, L-quisqualate, and the allosteric modulator Ro 67-4853 by extracellular Ca2+. These studies reveal that binding of extracellular Ca2+ to the predicted Ca2+-binding site in the ECD of mGluR1α modulates not only glutamate-evoked signaling but also the actions of both orthosteric ligands and allosteric modulators on mGluR1α