Anca Dragomir

The role of SATB2 as a diagnostic marker for tumors of colorectal origin : Results of a pathology-based clinical prospective study

OBJECTIVES Immunohistochemistry is an important extension to clinical information and morphology, and prevails as an invaluable tool for establishing a correct cancer diagnosis in clinical diagnostic pathology. The applicability of immunohistochemistry is limited by the availability of validated cell- and cancer-type specific antibodies, rendering an unmet need to discover, test, and validate novel markers. The SATB2 protein is selectively expressed in glandular cells from the lower gastrointestinal tract and expression is retained in a large majority of primary and metastatic colorectal cancers. METHODS We analyzed the expression of SATB2 in all clinical cases (n = 840), in which immunohistochemistry for detection of CK20 was deemed necessary for a final diagnosis. RESULTS SATB2 showed a high sensitivity (93%) and specificity (77%) to determine a cancer of colorectal origin and in combination with CK7 and CK20, the specificity increased to 100%. CONCLUSIONS We conclude that SATB2 provides a new and advantageous supplement for clinical differential diagnostics.

CFTR and tight junctions in cultured bronchial epithelial cells.

Airway epithelial salt and water transport takes place through paracellular and transcellular pathways. This transport depends critically on the epithelial sodium channel (ENaC) and the cystic fibrosis transmembrane conductance regulator (CFTR), operating in concert with the paracellular pathway through the tight junctions (TJ). Normal (16HBE14o-), cystic fibrosis (CFBE41o-), and corrected CFBE41o- (CFBE41o-pCep4 overexpressing wtCFTR) airway epithelial cell lines were cultured under isotonic conditions. Transepithelial electrical resistance (TEER) was measured as indicator of the tightness of the cultures. Morphology was investigated by immunofluorescence and paracellular permeability by lanthanum nitrate or [14C] mannitol as permeability markers. The CFTR-defective cell line CFBE41o- developed higher TEER than its corrected counterpart CFBE41o-pCep4. Addition of a specific inhibitor of CFTR (CFTR(inh)-172) to 16HBE14o- and CFBE41o-pCep4 cells resulted in a time-dependent increase in TEER, whereas stimulation of CFTR by IBMX and forskolin caused a decrease. Permeability to lanthanum and [14C] mannitol was lower in CFBE41o- and in 16HBE14o- cells exposed to CFTR(inh)-172, compared to untreated 16HBE14o- and CFBE41o-pCep4 cells, respectively. 16HBE14o- cells exposed to IBMX and forskolin showed higher permeability to lanthanum but lower permeability to [14C] mannitol compared to control. Immunofluorescence revealed a disorganization of F-actin and alpha-tubulin in 16HBE14o- cells and CFBE41o- pCep4 exposed to CFTR(inh)-172 and in CFBE41o- cells. Changes in F-actin and alpha-tubulin in 16HBE14o- cells exposed to IBMX and forskolin were also seen. These results suggest the possibility of an interaction between CFTR and the TJ protein complex, probably via the cytoskeleton.

High BRAF Mutation Frequency and Marked Survival Differences in Subgroups According to KRAS/BRAF Mutation Status and Tumor Tissue Availability in a Prospective Population-Based Metastatic Colorectal Cancer Cohort.

RAS and BRAF mutations impact treatment and prognosis of metastatic colorectal cancer patients (mCRC), but the knowledge is based on trial patients usually not representative for the general cancer population. Patient characteristics, treatment and efficacy according to KRAS, BRAF and MSI status were analyzed in a prospectively collected unselected population-based cohort of 798 non-resectable mCRC patients. The cohort contained many patients with poor performance status (39% PS 2-4) and elderly (37% age>75), groups usually not included in clinical trials. Patients without available tissue micro array (TMA) (42%) had worse prognostic factors and inferior survival (all patients; 7m vs 11m, chemotherapy-treated;12m vs 17m). The 92 patients (21%) with BRAF mutation had a poor prognosis regardless of microsatellite instability, but receipt of 1-2nd chemotherapy was similar to wildtype BRAF patients. Median survival in this cohort varied from 1 month in BRAF mutated patients not given chemotherapy to 26 months in wildtype KRAS/BRAF patients <75 years in good PS. TMA availability, BRAF mutation and KRAS mutation were all independent prognostic factors for survival. The observed 21% BRAF mutation incidence is higher than the previously and repeatedly reported incidence of 5-12% in mCRC. Screening for BRAF mutations before selection of treatment is relevant for many patients, especially outside clinical trials. A BRAF mutation only partly explained the very poor prognosis of many mCRC patients. Survival in unselected metastatic colorectal cancer patients is extremely variable and subgroups have an extremely short survival compared to trial patients. Patients without available TMA had worse prognostic factors and shorter survival, which questions the total generalizability of present TMA studies and implies that we lack information on the biologically worst mCRC cases. Lack of available tissue is an important underexposed issue which introduces sample bias, and this should be recognized more clearly when conclusions are made from translational mCRC studies.

Whole-exome sequencing identifies novel autosomal recessive DSG1 mutations associated with mild SAM syndrome

Whole-exome sequencing identifies novel autosomal recessive DSG1 mutations associated with mild SAM syndrome

Chitosan as a carrier for non‐viral gene transfer in a cystic‐fibrosis cell line

The gene transfer mediated by chitosan in CFBE41o− (a cystic‐fibrosis bronchial epithelial cell line) and HEK (a human embryonic kidney cell line) has been evaluated. Polyplexes based on chitosan and PEI (polyethyleneimine) using a luciferase and enhanced green fluorescent protein reporter plasmid showed that the transfection efficacy of polyplexes in the CFBE41o− cell line was poor compared with that in HEK cells. In the highly differentiated cystic‐fibrosis bronchial epithelial cell line the narrow‐size‐distributed chitosan shows enhanced transfection at a low pH compared with PEI. The enhanced transfection at lower pH could be a result of damage to the cell surface or changes in the cell‐surface charge, leading to better penetration of the cell membrane.

Assessment of chloride secretion in human nasal epithelial cells by X‐ray microanalysis

The genetic disease cystic fibrosis (CF) is due to defective epithelial chloride transport. Different treatments have been proposed that could restore chloride transport in CF patients. A new method is proposed for measuring the chloride secretion in easily accessible epithelial cells.

Survival-associated heterogeneity of marker-defined perivascular cells in colorectal cancer

Perivascular cells (PC) were recently implied as regulators of metastasis and immune cell activity. Perivascular heterogeneity in clinical samples, and associations with other tumor features and outcome, remain largely unknown. Here we report a novel method for digital quantitative analyses of vessel characteristics and PC, which was applied to two collections of human metastatic colorectal cancer (mCRC). Initial analyses identified marker-defined subsets of PC, including cells expressing PDGFR-β or α-SMA or both markers. PC subsets were largely independently expressed in a manner unrelated to vessel density and size. Association studies implied specific oncogenic mutations in malignant cells as determinants of PC status. Semi-quantitative and digital-image-analyses-based scoring of the NORDIC-VII cohort identified significant associations between low expression of perivascular PDGFR-α and -β and shorter overall survival. Analyses of the SPCRC cohort confirmed these findings. Perivascular PDGFR-α and -β remained independent factors for survival in multivariate analyses. Overall, our study identified host vasculature and oncogenic status as determinants of tumor perivascular features. Perivascular PDGFR-α and -β were identified as novel independent markers predicting survival in mCRC. The novel methodology should be suitable for similar analyses in other tumor collections.

X-Ray Microanalysis in the Scanning Electron Microscope

X-ray microanalysis conducted using the scanning electron microscope is a technique that allows the determination of chemical elements in bulk or semi-thick specimens. The lowest concentration of an element that can be detected is in the order of a few mmol/kg or a few hundred parts per million, and the smallest amount is in the order of 10(-18) g. The spatial resolution of the analysis depends on the thickness of the specimen. For biological specimen analysis, care must be taken to prevent displacement/loss of the element of interest (usually ions). Protocols are presented for the processing of frozen-hydrated and freeze-dried specimens, as well as for the analysis of small volumes of fluid, cell cultures, and other specimens. Aspects of qualitative and quantitative analysis are covered, including limitations of the technique.

The effect of S-nitrosoglutathione and L-cysteine on chloride efflux from cystic fibrosis airway epithelial cells

The endogenous bronchodilator, S-nitrosoglutathione (GSNO), has been proposed as a possible pharmacological remedy that reverses the ΔF508-CFTR (cystic fibrosis transmembrane conductance regulator) maturation defect and increases CFTR-mediated chloride efflux in cultured cystic fibrosis airway epithelial cells (CFBE41o(-)). It has also been reported that L-cysteine enhanced S-nitrosothiol uptake and increased the intracellular S-nitrosothiol levels, likely through transnitrosation chemistry. The present study investigated whether L-cysteine augmented the effect of GSNO on chloride efflux from CF airway epithelial cells. Treatment with 10 μM GSNO combined with 20 μM L-cysteine resulted in increased chloride efflux from CFBE41o(-) cells after 5 minutes exposure compared to the control efflux rate and to the efflux rate in the presence of L-cysteine alone as measured using the fluorescent dye N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (MQAE). Chloride efflux rates from these cells after 4h exposure to GSNO and L-cysteine were not different from control. Treatment with 10 μM GSNO alone increased chloride efflux from CFBE41o(-) cells after 4h but not at shorter incubation times. GSNO with or without L-cysteine did not alter epithelial tight junction integrity. In conclusion, a combination of GSNO with L-cysteine led to significant increase in chloride efflux in CFBE41o(-) cells but the effect was transient and not sustained beyond minutes.

Automated detection of cilia in low magnification transmission electron microscopy images using template matching

Ultrastructural analysis using Transmission Electron Microscopy (TEM) is a common approach for diagnosing primary ciliary dyskinesia. The manually performed diagnostic procedure is time consuming and subjective, and automation of the process is highly desirable. We aim at automating the search for plausible cilia instances in images at low magnification, followed by acquisition of high magnification images of regions with detected cilia for further analysis. This paper presents a template matching based method for automated detection of cilia objects in low magnification TEM images, where object radii do not exceed 10 pixels. We evaluate the performance of a series of synthetic templates generated for this purpose by comparing automated detection with results manually created by an expert pathologist. The best template achieves a detection at equal error rate of 47% which suffices to identify densely populated cilia regions suitable for high magnification imaging.