115 research outputs found
Retinoid metabolism and all-trans retinoic acid-induced growth inhibition in head and neck squamous cell carcinoma cell lines.
Retinoids can reverse potentially premalignant lesions and prevent second primary tumours in patients with head and neck squamous cell carcinoma (HNSCC). Furthermore, it has been reported that acquired resistance to all-trans retinoic acid (RA) in leukaemia is associated with decreased plasma peak levels, probably the result of enhanced retinoid metabolism. The aim of this study was to investigate the metabolism of retinoids and relate this to growth inhibition in HNSCC. Three HNSCC cell lines were selected on the basis of a large variation in the all-trans RA-induced growth inhibition. Cells were exposed to 9.5 nM (radioactive) for 4 and 24 h, and to 1 and 10 microM (nonradioactive) all-trans RA for 4, 24, 48 and 72 h, and medium and cells were analysed for retinoid metabolites. At all concentrations studied, the amount of growth inhibition was proportional to the extent at which all-trans-, 13- and 9-cis RA disappeared from the medium as well as from the cells. This turnover process coincided with the formation of a group of as yet unidentified polar retinoid metabolites. The level of mRNA of cellular RA-binding protein II (CRABP-II), involved in retinoid homeostasis, was inversely proportional to growth inhibition. These findings indicate that for HNSCC retinoid metabolism may be associated with growth inhibition
Extended Field Laser Confocal Microscopy (EFLCM): Combining automated Gigapixel image capture with in silico virtual microscopy
<p>Abstract</p> <p>Background</p> <p>Confocal laser scanning microscopy has revolutionized cell biology. However, the technique has major limitations in speed and sensitivity due to the fact that a single laser beam scans the sample, allowing only a few microseconds signal collection for each pixel. This limitation has been overcome by the introduction of parallel beam illumination techniques in combination with cold CCD camera based image capture.</p> <p>Methods</p> <p>Using the combination of microlens enhanced Nipkow spinning disc confocal illumination together with fully automated image capture and large scale <it>in silico </it>image processing we have developed a system allowing the acquisition, presentation and analysis of maximum resolution confocal panorama images of several Gigapixel size. We call the method Extended Field Laser Confocal Microscopy (EFLCM).</p> <p>Results</p> <p>We show using the EFLCM technique that it is possible to create a continuous confocal multi-colour mosaic from thousands of individually captured images. EFLCM can digitize and analyze histological slides, sections of entire rodent organ and full size embryos. It can also record hundreds of thousands cultured cells at multiple wavelength in single event or time-lapse fashion on fixed slides, in live cell imaging chambers or microtiter plates.</p> <p>Conclusion</p> <p>The observer independent image capture of EFLCM allows quantitative measurements of fluorescence intensities and morphological parameters on a large number of cells. EFLCM therefore bridges the gap between the mainly illustrative fluorescence microscopy and purely quantitative flow cytometry. EFLCM can also be used as high content analysis (HCA) instrument for automated screening processes.</p
Changes in the status of p53 affect drug sensitivity to thymidylate synthase (TS) inhibitors by altering TS levels
Colorectal cancer (CRC) resistance to fluoropyrimidines and other inhibitors of thymidylate synthase (TS) is a serious clinical problem often associated with increased intracellular levels of TS. Since the tumour suppressor gene p53, which is mutated in 50% of CRC, regulates the expression of several genes, it may modulate TS activity, and changes in the status of p53 might be responsible for chemoresistance. Therefore, this study was aimed to investigate TS levels and sensitivity to TS inhibitors in wild-type (wt) and mutant (mt) p53 CRC cells, Lovo and WiDr, respectively, transfected with mt and wt p53. Lovo 175X2 cells (transfected with mt p53) were more resistant to 5-fluorouracil (5-FU; 2-fold), nolatrexed (3-fold), raltitrexed (3-fold) and pemetrexed (10-fold) in comparison with the wt p53 parental cells Lovo 92. Resistance was associated with an increase in TS protein expression and catalytic activity, which might be caused by the loss of the inhibitory effect on the activity of TS promoter or by the lack of TS mRNA degradation, as suggested by the reversal of TS expression to the levels of Lovo 92 cells by adding actinomycin. In contrast, Lovo li cells, characterized by functionally inactive p53, were 3-13-fold more sensitive to nolatrexed, raltitrexed and pemetrexed, and had a lower TS mRNA, protein expression and catalytic activity than Lovo 92. However, MDM-2 expression was significantly higher in Lovo li, while no significant differences were observed in Lovo 175X2 cells with respect to Lovo 92. Finally, mt p53 WiDr transfected with wt p53 were not significantly different from mt p53 WiDr cells with respect to sensitivity to TS inhibitors or TS levels. Altogether, these results indicate that changes in the status of p53, can differently alter sensitivity to TS inhibitors by affecting TS levels, depending on activity or cell line, and might explain the lack of clear correlation between mutations in p53 and clinical outcome after chemotherapy with TS inhibitors
DPHL: A DIA Pan-human Protein Mass Spectrometry Library for Robust Biomarker Discovery
To address the increasing need for detecting and validating protein biomarkers in clinical specimens, mass spectrometry (MS)-based targeted proteomic techniques, including the selected reaction monitoring (SRM), parallel reaction monitoring (PRM), and massively parallel data-independent acquisition (DIA), have been developed. For optimal performance, they require the fragment ion spectra of targeted peptides as prior knowledge. In this report, we describe a MS pipeline and spectral resource to support targeted proteomics studies for human tissue samples. To build the spectral resource, we integrated common open-source MS computational tools to assemble a freely accessible computational workflow based on Docker. We then applied the workflow to generate DPHL, a comprehensive DIA pan-human library, from 1096 data-dependent acquisition (DDA) MS raw files for 16 types of cancer samples. This extensive spectral resource was then applied to a proteomic study of 17 prostate cancer (PCa) patients. Thereafter, PRM validation was applied to a larger study of 57 PCa patients and the differential expression of three proteins in prostate tumor was validated. As a second application, the DPHL spectral resource was applied to a study consisting of plasma samples from 19 diffuse large B cell lymphoma (DLBCL) patients and 18 healthy control subjects. Differentially expressed proteins between DLBCL patients and healthy control subjects were detected by DIA-MS and confirmed by PRM. These data demonstrate that the DPHL supports DIA and PRM MS pipelines for robust protein biomarker discovery. DPHL is freely accessible at https://www.iprox.org/page/project.html?id=IPX0001400000
Detection of circulating tumor cells in breast cancer may improve through enrichment with anti-CD146
Most assays to detect circulating tumor cells (CTCs) rely on EpCAM expression on tumor cells. Recently, our group reported that in contrast to other molecular breast cancer subtypes, "normal-like" cell lines lack EpCAM expression and are thus missed when CTCs are captured with EpCAM-based technology [J Natl Cancer Inst 101(1):61-66, 2009]. Here, the use of CD146 is introduced to detect EpCAM-negative CTCs, thereby improving CTC detection. CD146 and EpCAM expression were assessed in our panel of 41 breast cancer cell lines. Cells from 14 cell lines, 9 of which normal-like, were spiked into healthy donor blood. Using CellSearch (TM) technology, 7.5 ml whole blood was enriched for CTCs by adding ferrofluids loaded with antibodies against EpCAM and/or CD146 followed by staining for Cytokeratin and DAPI. Hematopoietic cells and circulating endothelial cells (CECs) were counterstained with CD45 and CD34, respectively. A similar approach was applied for blood samples of 20 advanced breast cancer patients. Eight of 9 normal-like breast cancer cell lines lacked EpCAM expression but did express CD146. Five of these 8 could be adequately recovered by anti-CD146 ferrofluids. Of 20 advanced breast cancer patients whose CTCs were enumerated with anti-EpCAM and anti-CD146 ferrofluids, 9 had CD146+ CTCs. Cells from breast cancer cell lines that lack EpCAM expression frequently express CD146 and can be recovered by anti-CD146 ferrofluids. CD146+ CTCs are present in the peripheral blood of breast cancer patients with advanced disease. Combined use of anti-CD146 and anti-EpCAM is likely to improve CTC detection in breast cancer patients
Detection and localization of early- and late-stage cancers using platelet RNA
Cancer patients benefit from early tumor detection since treatment outcomes are more favorable for less advanced cancers. Platelets are involved in cancer progression and are considered a promising biosource for cancer detection, as they alter their RNA content upon local and systemic cues. We show that tumor-educated platelet (TEP) RNA-based blood tests enable the detection of 18 cancer types. With 99% specificity in asymptomatic controls, thromboSeq correctly detected the presence of cancer in two-thirds of 1,096 blood samples from stage I–IV cancer patients and in half of 352 stage I–III tumors. Symptomatic controls, including inflammatory and cardiovascular diseases, and benign tumors had increased false-positive test results with an average specificity of 78%. Moreover, thromboSeq determined the tumor site of origin in five different tumor types correctly in over 80% of the cancer patients. These results highlight the potential properties of TEP-derived RNA panels to supplement current approaches for blood-based cancer screening
SIPcharts using uniform ultra-thin and thin fluorescent layers for z-response measurements in two-photon excitation fluorescence microscopy
Layer-by-Layer or self-assembly techniques can be used to prepare fluorescent polymer samples on glass coverslips serving as benchmark for two-photon excitation microscopy from conventional to 4Pi set-up, or more in general for sectioning microscopy.1-3 Layers can be realized as ultra-thin ( 6a 100 nm) or thin (approx. 100 nm) characteristics coupled to different fluorescent molecules to be used for different microscopy applications. As well, stacks hosting different fluorescent molecules can be also produce. Thanks to their controllable thickness, uniformity and fluorescence properties, these polymer layers may serve as a simple and applicable standard to directly measure the z-response of different scanning optical microscopes. In two-photon excitation microscopy z-sectioning plays a central role and uniformity of illumination is crucial due to the non-linear behaviour of emission. Since the main characteristics of a particular image formation situation can be efficiently summarized in a Sectioned Imaging property chart (SIPchart),3 we think that coupling this calibration sample with SIPchart is a very important step towards quantitative microscopy. In this work we use these polymer layers to measure the z-response of confocal, two-photon excitation and 4Pi laser scanning microscopes, selecting properly ultra-thin and thin layers. Due to their uniformity over a wide region, i.e. coverslip surface, it is possible to quantify the zresponse of the system over a full field of view area. These samples are also useful for monitoring photobleaching behavior as function of the illumination intensity. Ultrathin layers are also useful to supersede the conventional technique of calculating the derivative of the axial edges of a thick fluorescent layer. Polymer layers can be efficiently used for real time alignment of the microscope
SIPcharts using uniform ultra-thin and thin layers for Z-response measurements in two-photon excitation fluorescence microscopy
Layer-by-Layer or self-assembly techniques can be used to prepare fluorescent polymer samples on glass coverslips serving as benchmark for two-photon excitation microscopy from conventional to 4Pi set-up, or more in general for sectioning microscopy.1-3 Layers can be realized as ultra-thin (≪ 100 nm) or thin (approx. 100 nm) characteristics coupled to different fluorescent molecules to be used for different microscopy applications. As well, stacks hosting different fluorescent molecules can be also produce. Thanks to their controllable thickness, uniformity and fluorescence properties, these polymer layers may serve as a simple and applicable standard to directly measure the z-response of different scanning optical microscopes. In two-photon excitation microscopy z-sectioning plays a central role and uniformity of illumination is crucial due to the non-linear behaviour of emission. Since the main characteristics of a particular image formation situation can be efficiently summarized in a Sectioned Imaging property chart (SIPchart),3 we think that coupling this calibration sample with SIPchart is a very important step towards quantitative microscopy. In this work we use these polymer layers to measure the z-response of confocal, two-photon excitation and 4Pi laser scanning microscopes, selecting properly ultra-thin and thin layers. Due to their uniformity over a wide region, i.e. coverslip surface, it is possible to quantify the zresponse of the system over a full field of view area. These samples are also useful for monitoring photobleaching behavior as function of the illumination intensity. Ultrathin layers are also useful to supersede the conventional technique of calculating the derivative of the axial edges of a thick fluorescent layer. Polymer layers can be efficiently used for real time alignment of the microscope
An optimized methodology for combined phenotyping and genotyping on CYP2D6 and CYP2C19
A method for simultaneous phenotyping and genotyping for CYP2D6 and CYP2C19 was tested. Six healthy volunteers were selected (three extensive and three poor metabolisers for CYP2D6). CYP2D6 was probed with dextromethorphan and metoprolol and CYP2C19 was probed with omeprazole. Blood samples were collected and analysed for dextromethorphan, dextrorphan, metoprolol, alpha -hydroxymetoprol, omeprazole and 5-hydroxyomeprazole by HPLC. Genotyping was performed for both CYP2D6 and CYP2C19. Generally, plasma levels could be measured up to 8 h post-dose except for alpha -hydroxymetoprolol in poor metabolizers (PMs) and dextromethorphan in extensive metabolizers (EMs) (35% below quantification limit). The correlation between the metabolic ratio based on timed individual measurements and the metabolic ratio based on the AUC(0-12) values was significant at 3 h postdose for all probes. In conclusion, the following procedure is suggested: administer metoprolol (100 mg) and omeprazole (40 mg); after 3 h, take a blood sample to assess the genotype and the metabolic ratio for CYP2D6 (metoprolol over alpha -hydroxymetoprolol) and CYP2C19 (omeprazole over 5-hydroxyomeprazole) in plasma. With this procedure, all necessary information on the individual CYP2D6 and CYP2C19 metabolising capacity can be obtained in a practical, single-sample approach.</p
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