Name: employing digital droplet pcr to detect braf v600e mutations in formalin-fixed paraffin-embedded reference standard cell lines
Uploaded: 2015-10-08T14:00:00
Description: Watch this Scientific Journal Video about Employing Digital Droplet PCR to Detect BRAF V600E Mutations in Formalin-fixed Paraffin-embedded Reference Standard Cell Lines at JoVE.com

This research was supported by the R&#38;D Program for the Society&#160;of the National Research Foundation (NRF), funded by the Ministry of Science, ICT &#38; Future Planning (Grant No. 2013M3C8A1075908).

1. DNA Extraction from FFPE Reference Standard Cell Lines
Note: For this procedure, DNA extraction was performed from FFPE reference standard cell lines (HD598, HD593, HD617, HD273 and wildtype (WT)) using the FFPE Tissue DNA isolation kit as described in the protocol below. Automated DNA extraction was achieved by following the manufacturer&#39;s instructions for total DNA isolation.
<ol>
	<li>Using a microtome and the original FFPE block, manually prepare fresh sections prior to DNA extrac...

<ol>
	<li>Vogelstein, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+alterations+during+colorectal-tumor+development.">Genetic alterations during colorectal-tumor development.</a> The New England journal of medicine. 319, 525-532 (1988).</li><li>Davies, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutations+of+the+BRAF+gene+in+human+cancer.">Mutations of the BRAF gene in human cancer.</a> Nature. 417, 949-954 (2002).</li><li>Solit, D. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BRAF+mutation+predicts+sensitivity+to+MEK+inhibition.">BRAF mutation predicts sensitivity to MEK inhibition.</a> Nature. 439, 358-362 (2006).</li><li>Wong, K. 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J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-Throughput+Droplet+Digital+PCR+System+for+Absolute+Quantitation+of+DNA+Copy+Number.">High-Throughput Droplet Digital PCR System for Absolute Quantitation of DNA Copy Number.</a> Anal Chem. 83, 8604-8610 (1021).</li><li>Pinheiro, L. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+a+Droplet+Digital+Polymerase+Chain+Reaction+Format+for+DNA+Copy+Number+Quantification.">Evaluation of a Droplet Digital Polymerase Chain Reaction Format for DNA Copy Number Quantification.</a> Anal Chem. 84, 1003-1011 (1021).</li><li>Jones, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low+copy+target+detection+by+Droplet+Digital+PCR+through+application+of+a+novel+open+access+bioinformatic+pipeline,+'definetherain'.">Low copy target detection by Droplet Digital PCR through application of a novel open access bioinformatic pipeline, 'definetherain'.</a> Journal of virological methods. 202, 46-53 (2014).</li><li>Strain, M. 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A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determining+lower+limits+of+detection+of+digital+PCR+assays+for+cancer-related+gene+mutations.">Determining lower limits of detection of digital PCR assays for cancer-related gene mutations.</a> Biomolecular detection and quantification. 1, 8-22 (2014).</li><li>Zhu, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+Sensitive+Droplet+Digital+PCR+Method+for+Detection+of+EGFR+Activating+Mutations+in+Plasma+Cell-Free+DNA+from+Patients+with+Advanced+Non-Small+Cell+Lung+Cancer.">Highly Sensitive Droplet Digital PCR Method for Detection of EGFR Activating Mutations in Plasma Cell-Free DNA from Patients with Advanced Non-Small Cell Lung Cancer.</a> The Journal of molecular diagnostics: JMD. , (2015).</li><li>Fan, H., Gulley, M. 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Here, we highlight the applicability of ddPCR and DNA isolation from FFPE reference standard cell line samples for a specific gene mutation assessment. In this study, TPS automated DNA isolation method is used which can be readily adapted, automated, and can accommodate up to 48 different samples simultaneously, allowing for larger scale experiments and lower variability. One of the limitations of the DNA isolation in the present work is that every FFPE sample is unique, and will vary one another in surface contaminants,...

The accumulation of genetic mutations in key regulatory genes alters normal cell programing like cell proliferation, differentiation, and survival, leading to cancer1. The RAS-RAF-MAP kinase pathway mediates cellular responses to growth signals. Oncogenic BRAF mutations can result from driver mutations in the&#160;BRAF&#160;gene, which may cause the BRAF oncoprotein to become overactive2.&#160;Mutations in the&#160;BRAF&#160;gene also result in overactive downstream signaling via MEK and ERK3, which, in turn, leads to excessive cell growth and proliferation independently of growth&#160;factor-mediated regulation4-6.
Several tools are available for DNA mutation profiling, such as quantitative real-time&#160;BRAF V600E mutations in formalin-fixed, paraffin-embedded (FFPE) reference standard cell lines by ddPCR. ddPCR is an PCR-based method for absolute quantification offering higher accuracy compared to conventional quantitative real-time PCR (qPCR)7,8. ddPCR also provides higher resolving power and accuracy for the detection of rare mutations in DNA templates, enabling more informative cancer research and diagnosis9. Additional advantages of ddPCR over conventional qPCR include its enhanced sensitivity and accuracy when studying low template copy numbers10-12. Herein, a protocol for automatically extracting DNA from FFPE reference standard cell lines, followed by determining the presence or absence of BRAF V600E mutations by ddPCR is demonstrated. The usage of software for data analysis and a graphical representation of the results are also described. The entire procedure is relatively simple and totally depends on the number of samples to be profiled and the number of conventional PCR and ddPCR machines available.
The following protocol describes standard procedures for BRAF V600E-positive FFPE reference standard cell lines (HD598, HD593, HD617, HD273 and wildtype (WT)) is performed in a fully automated instrument using the Tissue Preparation System (TPS) protocol. Subsequently, isolated DNA samples are analyzed for the presence of BRAF V600E mutations using ddPCR system. Targeted mutation analysis is performed after all samples have been profiled and the data has been loaded into the data analysis software. Depending on the number of samples/groups studied, data analysis may require from one to several hours. The experimental component of the methodology requires accuracy in handling&#160;<a href="http://www.jove.com/science-education/5096/isolating-nucleic-acids-from-yeast" title="Isolating Nucleic Acids from Yeast, a JoVE Science Education video explaining more about about the context of RNA">DNA</a>&#160;and <a href="http://www.jove.com/science-education/5034/introduction-to-serological-pipettes-and-pipettors" title="Introduction to Serological Pipettes and Pipettors, a JoVE Science Education video explaining more about about the context of pipetting">pipetting</a>&#160;into 96 well plates, while data analysis is performed using software.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>&#160;Hamilton MICROLAB STARlet IVD instrument</td>
			<td>Siemens</td>
			<td>10701001</td>
			<td>Automated DNA isolation instrument</td>
		</tr>
		<tr>
			<td>QX200 Droplet Generator&#160;</td>
			<td>Bio-Rad</td>
			<td>772BR1119</td>
			<td></td>
		</tr>
		<tr>
			<td>QX200 Droplet Reader</td>
			<td>Bio-Rad</td>
			<td>771BR1497</td>
			<td></td>
		</tr>
		<tr>
			<td>Conventional PCR machine capable of ramp-time adjustment</td>
			<td></td>
			<td>621BR17718</td>
			<td></td>
		</tr>
		<tr>
			<td>PX1 PCR plate sealer</td>
			<td>Bio-Rad</td>
			<td>770BR1575</td>
			<td></td>
		</tr>
		<tr>
			<td>QuantaSoft software</td>
			<td>Bio-Rad</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>DNA isolation kit&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>VERSANT Tissue Preparation Reagents Box 1&#160;</td>
			<td>Siemens</td>
			<td>10632398</td>
			<td></td>
		</tr>
		<tr>
			<td>VERSANT Tissue Preparation Reagents Box 1&#160;</td>
			<td>Siemens</td>
			<td>10632399</td>
			<td></td>
		</tr>
		<tr>
			<td>CO-RE tips</td>
			<td>Siemens</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ddPCR mutation analysis</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ddPCR Supermix&#160;</td>
			<td>Bio-Rad&#160;</td>
			<td>BR186-3010</td>
			<td>2X concentration</td>
		</tr>
		<tr>
			<td>DG8 cartridge&#160;</td>
			<td>Bio-Rad&#160;</td>
			<td>BR186-4008</td>
			<td></td>
		</tr>
		<tr>
			<td>Droplet Generator oil</td>
			<td>Bio-Rad&#160;</td>
			<td>BR-186-3005</td>
			<td></td>
		</tr>
		<tr>
			<td>Gasket</td>
			<td>Bio-Rad&#160;</td>
			<td>BR186-3006</td>
			<td></td>
		</tr>
		<tr>
			<td>Droplet reader oil</td>
			<td>Bio-Rad&#160;</td>
			<td>BR-186-3004</td>
			<td></td>
		</tr>
	</tbody>
</table>

employing digital droplet pcr to detect braf v600e mutations in formalin-fixed paraffin-embedded reference standard cell lines

ddPCR is a highly sensitive PCR method that utilizes a water-oil emulsion system. Using a droplet generator, an extracted nucleic acid sample is partitioned into ~20,000 nano-sized, water-in-oil droplets, and PCR amplification occurs in individual droplets. The ddPCR approach is in identifying sequence mutations, copy number alterations, and select structural rearrangements involving targeted genes. Here, we demonstrate the use of ddPCR as a powerful technique for precisely quantitating rare BRAF V600E mutations in FFPE reference standard cell lines, which is helpful in identifying individuals with cancer. In conclusion, ddPCR technique offers the potential to precisely profile the specific rare mutations in different genes in various types of FFPE samples.

For our ddPCR analysis, we studied the BRAF V600E mutation FFPE reference standard cell lines. The droplet reader connects to a laptop computer running data analysis software. Each individual droplet is defined on the basis of fluorescent amplitude as being either positive or negative. The software provided by manufacturer also allows a user-defined cutoff to be entered to define the threshold between the positive and negative droplets. The number of positive and negative droplets in a sample is used to calculat...

Watch this Scientific Journal Video about Employing Digital Droplet PCR to Detect BRAF V600E Mutations in Formalin-fixed Paraffin-embedded Reference Standard Cell Lines at JoVE.com

Employing Digital Droplet PCR to Detect BRAF V600E Mutations in Formalin-fixed Paraffin-embedded Reference Standard Cell Lines

The goal of this video is to demonstrate how to perform&#160;automated DNA extraction from formalin-fixed paraffin-embedded (FFPE) reference standard cell lines and digital droplet PCR&#160;(ddPCR) analysis to detect rare mutations in a clinical setting. Detecting mutations in FFPE samples demonstrates the clinical utility of ddPCR in FFPE samples.

ddPCR is a highly sensitive PCR method that utilizes a water-oil emulsion system. Using a droplet generator, an extracted nucleic acid sample is ...

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Biology

Paraffin-Embedded and Frozen Sections of Drosophila Adult Muscles

The molecular characterization of muscular dystrophies and myopathies in humans has revealed the complexity of muscle disease and genetic analysis of muscle specification, formation and function in model systems has provided valuable insight into muscle physiology. Therefore, identifying and characterizing molecular mechanisms that underlie muscle damage is critical. The structure of adult Drosophila multi-fiber muscles resemble vertebrate striated muscles 1 and the genetic tractability of Drosophila has made it a great system to analyze dystrophic muscle morphology and characterize the processes affecting muscular function in ageing adult flies 2. Here we present the histological technique for preparing paraffin-embedded and frozen sections of Drosophila thoracic muscles. These preparations allow for the tissue to be stained with classical histological stains and labeled with protein detecting dyes, and specifically cryosections are ideal for immunohistochemical detection of proteins in intact muscles. This allows for analysis of muscle tissue structure, identification of morphological defects, and detection of the expression pattern for muscle/neuron-specific proteins in Drosophila adult muscles. These techniques can also be slightly modified for sectioning of other body parts.

Paraffin-Embedded and Frozen Sections of Drosophila Adult Muscles

Identification of mechanisms underlying muscle damage is crucial. Here we present the histological technique for preparing paraffin-embedded and frozen sections of Drosophila thoracic muscles. This allows analysis of muscle morphology and localization of protein and other muscle cell components.

The molecular characterization of muscular dystrophies and myopathies in humans has revealed the complexity of muscle disease and genetic analysis of ...

DNA Extraction from Paraffin Embedded Material for Genetic and Epigenetic Analyses

Disease development and progression are characterized by frequent genetic and epigenetic aberrations including chromosomal rearrangements, copy number gains and losses and DNA methylation. Advances in high-throughput, genome-wide profiling technologies, such as microarrays, have significantly improved our ability to identify and detect these specific alterations. However as technology continues to improve, a limiting factor remains sample quality and availability. Furthermore, follow-up clinical information and disease outcome are often collected years after the initial specimen collection. Specimens, typically formalin-fixed and paraffin embedded (FFPE), are stored in hospital archives for years to decades. DNA can be efficiently and effectively recovered from paraffin-embedded specimens if the appropriate method of extraction is applied. High quality DNA extracted from properly preserved and stored specimens can support quantitative assays for comparisons of normal and diseased tissues and generation of genetic and epigenetic signatures 1. To extract DNA from paraffin-embedded samples, tissue cores or microdissected tissue are subjected to xylene treatment, which dissolves the paraffin from the tissue, and then rehydrated using a series of ethanol washes. Proteins and harmful enzymes such as nucleases are subsequently digested by proteinase K. The addition of lysis buffer, which contains denaturing agents such as sodium dodecyl sulfate (SDS), facilitates digestion 2. Nucleic acids are purified from the tissue lysate using buffer-saturated phenol and high speed centrifugation which generates a biphasic solution. DNA and RNA remain in the upper aqueous phase, while proteins, lipids and polysaccharides are sequestered in the inter- and organic-phases respectively. Retention of the aqueous phase and repeated phenol extractions generates a clean sample. Following phenol extractions, RNase A is added to eliminate contaminating RNA. Additional phenol extractions following incubation with RNase A are used to remove any remaining enzyme. The addition of sodium acetate and isopropanol precipitates DNA, and high speed centrifugation is used to pellet the DNA and facilitate isopropanol removal. Excess salts carried over from precipitation can interfere with subsequent enzymatic assays, but can be removed from the DNA by washing with 70% ethanol, followed by centrifugation to re-pellet the DNA 3. DNA is re-suspended in distilled water or the buffer of choice, quantified and stored at -20&deg;C. Purified DNA can subsequently be used in downstream applications which include, but are not limited to, PCR, array comparative genomic hybridization 4 (array CGH), methylated DNA Immunoprecipitation (MeDIP) and sequencing, allowing for an integrative analysis of tissue/tumor samples.

This video demonstrates the protocol for DNA extraction from formalin-fixed paraffin-embedded material. This is a multi-day procedure in which tissue sections are deparaffinized with xylene, rehydrated with ethanol and treated with proteinase K to purify and isolate DNA for subsequent gene-specific or genome-wide analysis.

Disease development and progression are characterized by frequent genetic and epigenetic aberrations including chromosomal rearrangements, copy number ...

Use of LysoTracker to Detect Programmed Cell Death in Embryos and Differentiating Embryonic Stem Cells

Programmed cell death (PCD) occurs in adults to maintain normal tissue homeostasis and during embryological development to shape tissues and organs1,2,6,7. During development, toxic chemicals or genetic alterations can cause an increase in PCD or change PCD patterns resulting in developmental abnormalities and birth defects3-5. To understand the etiology of these defects, the study of embryos can be complemented with in vitro assays that use differentiating embryonic stem (ES) cells.
Apoptosis is a well-studied form of PCD that involves both intrinsic and extrinsic signaling to activate the caspase enzyme cascade. Characteristic cell changes include membrane blebbing, nuclear shrinking, and DNA fragmentation. Other forms of PCD do not involve caspase activation and may be the end-result of prolonged autophagy. Regardless of the PCD pathway, dying cells need to be removed. In adults, the immune cells perform this function, while in embryos, where the immune system has not yet developed, removal occurs by an alternative mechanism. This mechanism involves neighboring cells (called "non-professional phagocytes") taking on a phagocytic role-they recognize the 'eat me' signal on the surface of the dying cell and engulf it8-10. After engulfment, the debris is brought to the lysosome for degradation. Thus regardless of PCD mechanism, an increase in lysosomal activity can be correlated with increased cell death.
To study PCD, a simple assay to visualize lysosomes in thick tissues and multilayer differentiating cultures can be useful. LysoTracker dye is a highly soluble small molecule that is retained in acidic subcellular compartments such as the lysosome11-13. The dye is taken up by diffusion and through the circulation. Since penetration is not a hindrance, visualization of PCD in thick tissues and multi-layer cultures is possible12,13. In contrast, TUNEL (Terminal deoxynucleotidyl transferase dUTP nick end labeling) analysis14, is limited to small samples, histological sections, and monolayer cultures because the procedure requires the entry/permeability of a terminal transferase.
In contrast to Aniline blue, which diffuses and is dissolved by solvents, LysoTracker Red DND-99 is fixable, bright, and stable. Staining can be visualized with standard fluorescent or confocal microscopy in whole-mount or section using aqueous or solvent-based mounting media12,13. Here we describe protocols using this dye to look at PCD in normal and sonic hedgehog null mouse embryos. In addition, we demonstrate analysis of PCD in differentiating ES cell cultures and present a simple quantification method. In summary, LysoTracker staining can be a great complement to other methods of detecting PCD.

We present a simple protocol to visualize regions of programmed cell death (PCD) in mouse embryos and differentiating embryonic stem (ES) cell cultures using a highly soluble dye called LysoTracker.

Programmed cell death (PCD) occurs in adults to maintain normal tissue homeostasis and during embryological development to shape tissues and ...

Proteomic Sample Preparation from Formalin Fixed and Paraffin Embedded Tissue

Preserved clinical material is a unique source for proteomic investigation of human disorders. Here we describe an optimized protocol allowing large scale quantitative analysis of formalin fixed and paraffin embedded (FFPE) tissue. The procedure comprises four distinct steps. The first one is the preparation of sections from the FFPE material and microdissection of cells of interest. In the second step the isolated cells are lysed and processed using 'filter aided sample preparation' (FASP) technique. In this step, proteins are depleted from reagents used for the sample lysis and are digested in two-steps using endoproteinase LysC and trypsin. 
After each digestion, the peptides are collected in separate fractions and their content is determined using a highly sensitive fluorescence measurement. Finally, the peptides are fractionated on 'pipette-tip' microcolumns. The LysC-peptides are separated into 4 fractions whereas the tryptic peptides are separated into 2 fractions. In this way prepared samples allow analysis of proteomes from minute amounts of material to a depth of 10,000 proteins. Thus, the described workflow is a powerful technique for studying diseases in a system-wide-fashion as well as for identification of potential biomarkers and drug targets.

Archival formalin fixed and paraffin embedded (FFPE) clinical samples are valuable material for investigation of diseases. Here we demonstrate a sample preparation workflow allowing in-depth proteomic analysis of microdissected FFPE tissue.

Preserved clinical material is a unique source for proteomic investigation of human disorders. Here we describe an optimized protocol allowing large scale ...

MicroRNA In situ Hybridization for Formalin Fixed Kidney Tissues

In this article we describe a method for colorimetric detection of miRNA in the kidney through in situ hybridization with digoxigenin tagged microRNA probes. This protocol, originally developed by Kloosterman and colleagues for broad use with Exiqon miRNA probes1, has been modified to overcome challenges inherent in miRNA analysis in kidney tissues. These include issues such as structure identification and hard to remove residual probe and antibody. Use of relatively thin, 5 mm thick, tissue sections allowed for clear visualization of kidney structures, while a strong probe signal was retained in cells. Additionally, probe concentration and incubation conditions were optimized to facilitate visualization of microRNA expression with low background and nonspecific signal. Here, the optimized protocol is described, covering the initial tissue collection and preparation through the mounting of slides at the end of the procedure. The basic components of this protocol can be altered for application to other tissues and cell culture models.

MicroRNA In situ Hybridization for Formalin Fixed Kidney Tissues

This article describes an in situ hybridization protocol optimized for colormetric detection of microRNA expression in formalin fixed kidney sections.

In this article we describe a method for colorimetric detection of miRNA in the kidney through in situ hybridization with digoxigenin tagged microRNA ...

Profiling Individual Human Embryonic Stem Cells by Quantitative RT-PCR

Heterogeneity of stem cell population hampers detailed understanding of stem cell biology, such as their differentiation propensity toward different lineages. A single cell transcriptome assay can be a new approach for dissecting individual variation. We have developed the single cell qRT-PCR method, and confirmed that this method works well in several gene expression profiles. In single cell level, each human embryonic stem cell, sorted by OCT4::EGFP positive cells, has high expression in OCT4, but a different level of NANOG expression. Our single cell gene expression assay should be useful to interrogate population heterogeneities.

Single cell gene expression assay is needed for understanding stem cell heterogeneities.

Heterogeneity of stem cell population hampers detailed understanding of stem cell biology, such as their differentiation propensity toward different ...

qPCR Is a Sensitive and Rapid Method for Detection of Cytomegaloviral DNA in Formalin-fixed, Paraffin-embedded Biopsy Tissue

It is crucial to identify cytomegalovirus (CMV) infection in the gastrointestinal (GI) tract of immunosuppressed patients, given their greater risk for developing severe infection. Many laboratory methods for the detection of CMV infection have been developed, including serology, viral culture, and molecular methods. Often, these methods reflect systemic involvement with CMV and do not specifically identify local tissue involvement. Therefore, detection of CMV infection in the GI tract is frequently done by traditional histology of biopsy tissue. Hematoxylin and eosin (H&#38;E) staining in conjunction with immunohistochemistry (IHC) have remained the mainstays of examining these biopsies. H&#38;E and IHC sometimes result in atypical (equivocal) staining patterns, making interpretation difficult. It was shown that quantitative polymerase chain reaction (qPCR) for CMV can successfully be performed on formalin-fixed, paraffin-embedded (FFPE) biopsy tissue for very high sensitivity and specificity. The goal of this protocol is to demonstrate how to perform qPCR testing for the detection of CMV in FFPE biopsy tissue in a clinical laboratory setting. This method is likely to be of great benefit for patients in cases of equivocal staining for CMV in GI biopsies.

This protocol describes qPCR detection of cytomegalovirus in formalin-fixed, paraffin-embedded biopsy tissue, which is rapid, sensitive, specific, and useful for interpreting equivocal hematoxylin and eosin or immunohistochemical staining patterns.

It is crucial to identify cytomegalovirus (CMV) infection in the gastrointestinal (GI) tract of immunosuppressed patients, given their greater risk for ...

Preparation of Formalin-fixed Paraffin-embedded Tissue Cores for both RNA and DNA Extraction

Formalin-fixed paraffin embedded tissue (FFPET) represents a valuable, well-annotated substrate for molecular investigations. The utility of FFPET in molecular analysis is complicated both by heterogeneous tissue composition and low yields when extracting nucleic acids. A literature search revealed a paucity of protocols addressing these issues, and none that showed a validated method for simultaneous extraction of RNA and DNA from regions of interest in FFPET. This method addresses both issues. Tissue specificity was achieved by mapping cancer areas of interest on microscope slides and transferring annotations onto FFPET blocks. Tissue cores were harvested from areas of interest using 0.6 mm microarray punches. Nucleic acid extraction was performed using a commercial FFPET extraction system, with modifications to homogenization, deparaffinization, and Proteinase K digestion steps to improve tissue digestion and increase nucleic acid yields. The modified protocol yields sufficient quantity and quality of nucleic acids for use in a number of downstream analyses, including a multi-analyte gene expression platform, as well as reverse transcriptase coupled real time PCR analysis of mRNA expression, and methylation-specific PCR (MSP) analysis of DNA methylation.

This modified extraction protocol improves RNA and DNA yields from more precisely targeted regions of interest in histopathologic tissue blocks.

Formalin-fixed paraffin embedded tissue (FFPET) represents a valuable, well-annotated substrate for molecular investigations. The utility of FFPET in ...

Magnetic-Activated Cell Sorting Strategies to Isolate and Purify Synovial Fluid-Derived Mesenchymal Stem Cells from a Rabbit Model

Mesenchymal stem cells (MSCs) are the main cell source for cell-based therapy. MSCs from articular cavity synovial fluid could potentially be used for cartilage tissue engineering. MSCs from synovial fluid (SF-MSCs) have been considered promising candidates for articular regeneration, and their potential therapeutic benefit has made them an important research topic of late. SF-MSCs from the knee cavity of the New Zealand white rabbit can be employed as an optimized translational model to assess human regenerative medicine. By means of CD90-based magnetic activated cell sorting (MACS) technologies, this protocol successfully obtains rabbit SF-MSCs (rbSF-MSCs) from this rabbit model and further fully demonstrates the MSC phenotype of these cells by inducing them to differentiate to osteoblasts, adipocytes, and chondrocytes. Therefore, this approach can be applied in cell biology research and tissue engineering using simple equipment and procedures.

This article presents a simple and economic protocol for the straightforward isolation and purification of mesenchymal stem cells from New Zealand white rabbit synovial fluid.

Mesenchymal stem cells (MSCs) are the main cell source for cell-based therapy. MSCs from articular cavity synovial fluid could potentially be used for ...

Quantitative Immunoblotting of Cell Lines as a Standard to Validate Immunofluorescence for Quantifying Biomarker Proteins in Routine Tissue Samples

Quantification of proteins of interest in formalin-fixed, paraffin-embedded (FFPE) tissue samples is important in clinical and research applications. An optimal method of quantification is accurate, has a broad linear dynamic range and maintains the structural integrity of the sample to allow for identification of individual cell types. Current methods such as immunohistochemistry (IHC), mass spectrometry, and immunoblotting each fail to meet these stipulations due to their categorical nature or need to homogenize the sample. As an alternative method, we propose the use of immunofluorescence (IF) and image analysis to determine the relative abundance of a protein of interest in FFPE tissues. Herein we demonstrate that this method is easily optimized, yields a wide dynamic range, and is linearly quantifiable as compared to the gold standard of quantitative immunoblotting. Furthermore, this method permits the maintenance of the structural integrity of the sample and allows for the distinction of various cell types, which may be crucial in diagnostic applications. Overall, this is a robust method for the relative quantification of proteins in FFPE samples and can be easily adapted to suit clinical or research needs.

We describe the use of quantitative immunoblotting to validate immunofluorescence histology coupled with image analysis as a means of quantifying a protein of interest in formalin-fixed, paraffin-embedded (FFPE) tissue samples. Our results demonstrate the utility of immunofluorescence histology for ascertaining the relative quantity of biomarker proteins in routine biopsy samples.

Quantification of proteins of interest in formalin-fixed, paraffin-embedded (FFPE) tissue samples is important in clinical and research applications. An ...