[Detection of BRAF mutation in canine prostatic diseases]. / Nachweis der BRAF-Mutation bei kaninen Prostataerkrankungen.

OBJECTIVE: In the literature, the BRAF mutation is reported to have been identified in 80 % of the examined canine prostate carcinomas (PCa). The objectives of this study were to test for the BRAF mutation in canine PCa in our cohort of canine patients, to determine the specificity and sensitivity of the test for this mutation, as well as to identify the association between the presence of the BRAF mutation and the histologic picture of PCa. Moreover, the method was to be established in cytology samples. MATERIAL AND METHODS: Biopsy samples (n = 70) and cytologic slides (n = 17) of 87 dogs with prostatic diseases were selected. Prostatic diseases were classified according to the literature as benign prostate hyperplasia (BPH, n = 22), prostatitis (n = 14), squamous cell metaplasia of the prostate (PM, n = 2), atrophy following castration (n = 3) und PCa (n = 46; histologic diagnosis n = 35, cytologic diagnosis n = 11). Additionally, the Gleason score was determined for each PCa. DNA isolation was performed using commercially available kits. Exon 15 was examined using the TaqMan® SNP assay. The specificity and sensitivity of the test were calculated. RESULTS: A Gleason score of 6 and 7 was shown in 1 PCa each, in 33 cases the score ranged between 8 and 10. Sufficient amount of good-quality DNA was isolated from all samples. 28/46 PCa were tested positive for the BRAF mutation (sensitivity 61 %). The BRAF mutation was not evident in any of the dogs with BPH, prostatitis, PM or atrophy (specificity 100 %). PCa positive for the BRAF mutation exhibited a significantly higher Gleason score (p = 0.002) in comparison to PCa without this mutation. CONCLUSION AND CLINICAL RELEVANCE: BRAF mutation analysis is a highly specific method and may aid in confirming the diagnosis of PCa in histologically and cytologically questionable cases. PCa positive for BRAF mutation exhibited more criteria of malignancy than PCa without this mutation. The clinical, therapeutic, and prognostic relevance of these findings needs to be evaluated by further studies.

Channelrhodopsin-1 Phosphorylation Changes with Phototactic Behavior and Responds to Physiological Stimuli in Chlamydomonas.

The unicellular alga Chlamydomonas (Chlamydomonas reinhardtii) exhibits oriented movement responses (phototaxis) to light over more than three log units of intensity. Phototaxis thus depends on the cell's ability to adjust the sensitivity of its photoreceptors to ambient light conditions. In Chlamydomonas, the photoreceptors for phototaxis are the channelrhodopsins (ChR)1 and ChR2; these light-gated cation channels are located in the plasma membrane. Although ChRs are widely used in optogenetic studies, little is known about ChR signaling in algae. We characterized the in vivo phosphorylation of ChR1. Its reversible phosphorylation occurred within seconds as a graded response to changes in the light intensity and ionic composition of the medium and depended on an elevated cytosolic Ca2+ concentration. Changes in the phototactic sign were accompanied by alterations in the phosphorylation status of ChR1. Furthermore, compared with the wild type, a permanently negative phototactic mutant required higher light intensities to evoke ChR1 phosphorylation. C-terminal truncation of ChR1 disturbed its reversible phosphorylation, whereas it was normal in ChR2-knockout and eyespot-assembly mutants. The identification of phosphosites in regions important for ChR1 function points to their potential regulatory role(s). We propose that multiple ChR1 phosphorylation, regulated via a Ca2+-based feedback loop, is an important component in the adaptation of phototactic sensitivity in Chlamydomonas.

Correlation of BRAF Variant V595E, Breed, Histological Grade and Cyclooxygenase-2 Expression in Canine Transitional Cell Carcinomas.

The presence of BRAF variant V595E, as well as an increased cyclooxygenase-2 (COX-2) expression in canine transitional cell carcinoma (TCC) are well-described in the literature. The aim of the present study was to investigate the correlation between breed (terrier versus non-terrier dogs), histological grade, COX-2 expression, and BRAF mutation in canine TCC. Therefore, transmural TCC biopsies from 65 dogs (15 terriers, 50 non-terriers) were graded histologically into low- and high-grade. Immunohistochemical evaluation of the intensity of COX-2 expression was performed using an immunoreactive score (IRS). Exon 15 of chromosome 16 was examined for the BRAF variant c.1799T>A by TaqMan® SNP assay. TCC was low-grade in 20 cases (one terrier, 19 non-terriers) and high-grade in 45 cases (14 terriers, 31 non-terriers). Contrary to humans, histological grade was not significantly correlated to the intensity of COX-2 expression. BRAF mutation was detected in 11/15 (73%) TCC of terriers and in 18/50 (36%) TCC of non-terriers. Histological grade and BRAF mutation were not correlated significantly (p = 0.2912). Terriers had a considerably higher prevalence of high-grade tumors (p < 0.0001), as well as of BRAF mutation (p ≤ 0.05) compared to non-terriers. In non-terriers, neoplasms with BRAF mutation showed a significantly higher intensity of COX-2 expression than those without BRAF mutation (p ≤ 0.05). In conclusion, in contrast to humans, testing for BRAF mutation in canine TCC is a sensitive diagnostic method especially in terriers (73%) and may be recommended as a screening test. However, evidence of BRAF mutation in canine TCC is not a predictor for the histological grade. Moreover, a positive correlation between histological grade and the intensity of COX-2 expression was not found. Further studies are necessary to clarify the clinical and prognostic relevance of the elevated intensity of COX-2 expression of TCC with BRAF mutation detected in non-terriers.