Rapid Report

Coexpression of KCNQ2 and KCNQ3 channels results in a 10-fold increased current amplitude compared to that of KCNQ2 alone, suggesting the formation of heteromultimeric channels. There is no interaction of either channel with KCNQ1. We evaluated the C-terminus as a potential interaction domain by construction of chimeras with interchanged C-termini of KCNQ1, KCNQ2 and KCNQ3 and functional expression in Xenopus oocytes. The chimera of KCNQ1 with a KCNQ2 C-terminus (Q1ctQ2) showed an 8-fold increase in current amplitude, and Q1ctQ3 a 3-fold increase when coexpressed with KCNQ3 and KCNQ2, respectively, indicating that the C-terminus contains an interaction domain. To characterize this interacting region, we studied further chimeras of KCNQ1 containing different parts of the KCNQ3 C-terminus for interaction with KCNQ2. We also evaluated short sequences of the KCNQ2 C-terminus for a dominant-negative effect on Q1ctQ3. According to the results of these experiments, functional interaction of KCNQ2 and KCNQ3 requires a highly conserved region of about 80 amino acids, previously called the A-domain, plus either 40 residues downstream of the A-domain (B-domain) or the proximal C-terminus between S6 and the A-domain. Furthermore, the chimeras Q1ctQ3 and Q2ctQ3 showed > 10-fold increased current amplitudes compared to KCNQ1 or KCNQ2 alone and a strong depolarizing shift of voltage-dependent activation. The proximal part of the KCNQ3 C-terminus was necessary to produce these effects. Our results indicate that specific parts of the C-terminus enable the interaction between KCNQ2 and KCNQ3 channels and that different parts of the KCNQ3 C-terminus are important for regulating current amplitude.     

A whole-slide imaging based workflow reduces the reading time of pathologists

Even though entirely digitized microscopic tissue sections (whole slide images, WSIs) are increasingly being used in histopathology diagnostics, little data is still available on the effect of this technique on pathologists' reading time. This study aimed to compare the time required to perform the microscopic assessment by pathologists between a conventional workflow (an optical microscope) and digitized WSIs. WSI was used in primary diagnostics at the Laboratory for Pathology Eastern Netherlands for several years (LabPON, Hengelo, The Netherlands). Cases were read either in a traditional workflow, with the pathologist recording the time required for diagnostics and reporting, or entirely digitally. Reading times were extracted from image management system log files, and the digitized workflow was fully integrated into the laboratory information system. The digital workflow saved time in the majority of case categories, with prostate biopsies saving the most (68% time gain). Taking into account case distribution, the digital workflow produced an average gain of 12.3%. Using WSI instead of conventional microscopy significantly reduces pathologists' reading times. Pathologists must work in a fully integrated environment to fully reap the benefits of a digital workflow.     

Investigation of an outbreak of amoebiasis in Georgia

Entamoeba histolytica, a protozoan parasite, occurs worldwide and 12% of the world's population are estimated to be infected. The prevalence of infection varies between 1% in industrialised countries to between 50% and 80% in tropical countries, where tra     

IGF-1R pathway activation as putative biomarker for linsitinib therapy to revert tamoxifen resistance in ER-positive breast cancer

Preclinical studies indicate that activated IGF-1R can drive endocrine resistance in ER-positive (ER+) breast cancer, but its clinical relevance is unknown. We studied the effect of IGF-1R signaling on tamoxifen benefit in patients and we searched for approaches to overcome IGF-1R-mediated tamoxifen failure in cell lines. Primary tumor blocks from postmenopausal ER+ breast cancer patients randomized between adjuvant tamoxifen versus nil were recollected. Immunohistochemistry for IGF-1R, p-IGF-1R/InsR, p-ERα(Ser118), p-ERα(Ser167) and PI3K/MAPK pathway proteins was performed. Multivariate Cox models were employed to assess tamoxifen efficacy. The association between p-IGF-1R/InsR and PI3K/MAPK pathway activation in MCF-7 and T47D cells was analyzed with Western blots. Cell proliferation experiments were performed under various growth-stimulating and -inhibiting conditions. Patients with ER+, IGF-1R-positive breast cancer without p-IGF-1R/InsR staining (n = 242) had tamoxifen benefit (HR 0.41, p = 0.0038), while the results for p-IGF-1R/InsR-positive patients (n = 125) were not significant (HR 0.95, p = 0.3). High p-ERα(Ser118) or p-ERα(Ser167) expression was associated with less tamoxifen benefit. In MCF-7 cells, IGF-1R stimulation increased phosphorylation of PI3K/MAPK proteins and ERα(Ser167) regardless of IGF-1R overexpression. This could be abrogated by the dual IGF-1R/InsR inhibitor linsitinib, but not by the IGF-IR-selective antibody 1H7. In MCF-7 and T47D cells, stimulation of the IGF-1R/InsR pathway resulted in cell proliferation regardless of tamoxifen. Abrogation of cell growth was regained by addition of linsitinib. In conclusion, p-IGF-1R/InsR positivity in ER+ breast cancer is associated with reduced benefit from adjuvant tamoxifen in postmenopausal patients. In cell lines, stimulation rather than overexpression of IGF-1R is driving tamoxifen resistance to be abrogated by linsitinib.     

The rate of cell growth is governed by cell cycle stage

Cell growth is an essential requirement for cell cycle progression. While it is often held that growth is independent of cell cycle position, this relationship has not been closely scrutinized. Here we show that in budding yeast, the ability of cells to grow changes during the cell cycle. We find that cell growth is faster in cells arrested in anaphase and G1 than in other cell cycle stages. We demonstrate that the establishment of a polarized actin cytoskeleton—either as a consequence of normal cell division or through activation of the mating pheromone response—potently attenuates protein synthesis and growth. We furthermore show by population and single-cell analysis that growth varies during an unperturbed cell cycle, slowing at the time of polarized growth. Our study uncovers a fundamental relationship whereby cell cycle position regulates growth.