Human phosphodiesterase 4D7 (PDE4D7) expression is increased in TMPRSS2-ERG-positive primary prostate cancer and independently adds to a reduced risk of post-surgical disease progression.

BACKGROUND: There is an acute need to uncover biomarkers that reflect the molecular pathologies, underpinning prostate cancer progression and poor patient outcome. We have previously demonstrated that in prostate cancer cell lines PDE4D7 is downregulated in advanced cases of the disease. To investigate further the prognostic power of PDE4D7 expression during prostate cancer progression and assess how downregulation of this PDE isoform may affect disease outcome, we have examined PDE4D7 expression in physiologically relevant primary human samples. METHODS: About 1405 patient samples across 8 publically available qPCR, Affymetrix Exon 1.0 ST arrays and RNA sequencing data sets were screened for PDE4D7 expression. The TMPRSS2-ERG gene rearrangement status of patient samples was determined by transformation of the exon array and RNA seq expression data to robust z-scores followed by the application of a threshold>3 to define a positive TMPRSS2-ERG gene fusion event in a tumour sample. RESULTS: We demonstrate that PDE4D7 expression positively correlates with primary tumour development. We also show a positive association with the highly prostate cancer-specific gene rearrangement between TMPRSS2 and the ETS transcription factor family member ERG. In addition, we find that in primary TMPRSS2-ERG-positive tumours PDE4D7 expression is significantly positively correlated with low-grade disease and a reduced likelihood of progression after primary treatment. Conversely, PDE4D7 transcript levels become significantly decreased in castration resistant prostate cancer (CRPC). CONCLUSIONS: We further characterise and add physiological relevance to PDE4D7 as a novel marker that is associated with the development and progression of prostate tumours. We propose that the assessment of PDE4D7 levels may provide a novel, independent predictor of post-surgical disease progression.

Examination of surface-bound Ku-DNA complexes in an aqueous environment using MAC mode atomic force microscopy.

In the development of biosensors, it is essential to understand how the signal-transducing element may perturb surface-bound proteins and nucleic acids. The tip of the atomic force microscope is such an element in atomic force microscopy. In this paper, we describe the influence of tip-sample interactions on the measured height of the DNA repair protein, Ku, that has been adsorbed onto a mica surface which was submerged in aqueous solution. We find that the measured height of the Ku molecule depends critically on whether or not it is associated with DNA. Additionally, we observed that the conditions (time and concentration) under which Ku is incubated with DNA, affect the appearance (number and type) of the DNA-Ku complexes observed.

Particle size does not affect the rate of intracellular routing for ligands internalized by non-adsorptive pinocytosis.

The rate at which three different species of a fluid phase marker (horseradish peroxidase) reached the lysosomal compartment of mouse LM fibroblasts was compared. Initial observations suggested that the rate was a function of particle size. Adjustment of the concentrations of the various species of HRP to equal numbers of physical particles negated the apparent affect. Thus, particle size does not affect the intracellular routing of a ligand entering fibroblasts by non-adsorptive pinocytosis.

Modulation of fibrin assembly and polymerization by the beta-amyloid of Alzheimer's disease.

Vascular deposition of amyloid beta protein (A beta P) is associated with recurrent intracerebral hemorrhages in certain disease states. Based upon these findings, we studied the effect of A beta P on fibrin (Fn) formation and fibrinolysis. We utilized electron microscopy and light scattering studies to examine alterations in the nature of the Fn clots obtained in the presence of the amyloid of Alzheimer's disease (AD), A beta P 1-40. Electron microscopic analysis revealed a network of FN and amyloid fibers formed in the presence of A beta P with significantly decreased lateral Fn-Fn interactions. Additional evidence for the assembly of an altered Fn matrix was obtained from kinetic assays that included fibrinogen (Fg), plasminogen, tissue-type plasminogen activator, and thrombin, in the presence of a fibril forming peptide derived from A beta P (A beta P 34-42). Turbidometric analysis of Fn clots showed that thrombin-treated Fg forms increasingly denser and more compact Fn fibers in the presence of increasing molar equivalents of A beta P 1-40. This conclusion was based upon the observed increases in the mass-to-length ratios, fiber radii, fiber densities, and the calculated number of Fn monomers per fiber cross-section. These results taken together suggest that amyloid forming peptides and proteins of AD significantly alter the nature of the Fn obtained in their presence.

Methods for measuring the strength of discriminable drug effects.

Drug discriminations can be used to investigate a variety of preclinical psychopharmacological issues. These discriminations are based on the so-called "discriminable" or "discriminative stimulus" effects of drugs. In order to conduct some types of drug discrimination studies, it is helpful or necessary to know the amount or degree of discriminability of the various drugs employed. This paper describes several methods for determining the degree of discriminability of drugs, and evaluates these methods primarily using data obtained by training rats to discriminate drug vs. no drug in a shock-escape T-maze task. The results suggest that useful indices of degree of discriminability can be computed from the rapidity with which drug discriminations are learned. Indices based on average accuracy during acquisition were found to be somewhat superior to indices based on sessions to criterion.

Cytophotometric studies in suspicious cervical smears.

Papanicolaou stained smears of various cervical lesions diagnosed as "suspicious" by routine cytology were reviewed with regard to different cell types leading to this diagnosis. The smears were then submitted to Feulgen hydrolysis and redyed by Acriflavin-SO2 for fluorescence-cytophotometry. In nine of 14 cases measured, the DNA content of all types of "suspicious" cells was increased with DNA modes at euploid levels of 2 n, 4 n and 8 n indicating that the "suspicious" cells in those cases are polyploid. However, in five cases aneuploid DNA-distribution patterns were found similar to those observed in carcinoma in situ or severe dysplasia. Since polyploidization may be considered as a cellular response to higher functional requirement (i.e. inflammation or regeneration) a "suspicious" cervical smear with a polyploid DNA-distribution pattern may reverse to normal cervical epithelium after normal conditions are restored. However, a "suspicious" smear with an aneuploid DNA-distribution pattern should be considered more seriously as being related to a precancerous lesion requiring immediate surgical treatment.