Name: retrospective microrna sequencing: complementary dna library preparation protocol using formalin-fixed paraffin-embedded rna specimens
Uploaded: 2018-05-05T13:00:00.000+00:00
Duration: 12 min 24 s
Description: Watch this Scientific Journal Video about Retrospective MicroRNA Sequencing: Complementary DNA Library Preparation Protocol Using Formalin-fixed Paraffin-embedded RNA Specimens at JoVE.com

We thank Dr. Thomas Tuschl, head of the laboratory for RNA molecular biology, as well as members of his laboratory for their support and for sharing the technology developed in his laboratory and providing access to the RNAworld pipeline. We also thank Dr. Markus Hafner for sharing his protocol and providing detailed descriptions on all biochemical and enzymatic steps used in his initial procedure.

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Pathol. 62, 84-88 (2009).</li><li>Jang, J. S., Simon, V. A., Feddersen, R. M., Rakhshan, F., Schultz, D. A., Zschunke, M. A., Lingle, W. L., Kolbert, C. P., Jen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+miRNA+expression+analysis+using+fluidigm+microfluidics+dynamic+arrays.">Quantitative miRNA expression analysis using fluidigm microfluidics dynamic arrays.</a> BMC Genomics. 12, 144 (2011).</li><li>Andreasen, D., Fog, J. U., Biggs, W., Salomon, J., Dahslveen, I. K., Baker, A., Mouritzen, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+microRNA+quantification+in+total+RNA+from+clinical+samples.">Improved microRNA quantification in total RNA from clinical samples.</a> Methods. 50 (4), S6-S9 (2010).</li><li>Kelly, A. D., Hill, K. E., Correll, M., Wang, Y. E., Rubio, R., Duan, S., 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=Next-generation+sequencing+and+microarray-based+interrogation+of+microRNAs+from+formalin-fixed,+paraffin-embedded+tissue:+preliminary+assessment+of+cross-platform+concordance.">Next-generation sequencing and microarray-based interrogation of microRNAs from formalin-fixed, paraffin-embedded tissue: preliminary assessment of cross-platform concordance.</a> Genomics. 102, 8-14 (2013).</li><li>Visone, R., Croce, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MiRNAs+and+cancer.">MiRNAs and cancer.</a> Am. J. Pathol. 174, 1131-1138 (2009).</li><li>Lu, J., Getz, G., Miska, E. A., Alvarez-Saavedra, E., Lamb, J., Peck, D., 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=MicroRNA+expression+profiles+classify+human+cancers.">MicroRNA expression profiles classify human cancers.</a> Nature. 435, 834-838 (2005).</li><li>Cho, W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MicroRNAs:+potential+biomarkers+for+cancer+diagnosis,+prognosis+and+targets+for+therapy.">MicroRNAs: potential biomarkers for cancer diagnosis, prognosis and targets for therapy.</a> Int. J. Biochem. Cell. Biol. 42, 1273-1281 (2010).</li><li>Hui, A., How, C., Ito, E., Liu, F. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micro-RNAs+as+diagnostic+or+prognostic+markers+in+human+epithelial+malignancies.">Micro-RNAs as diagnostic or prognostic markers in human epithelial malignancies.</a> BMC Cancer. 11, 500 (2011).</li><li>Tam, S., de Borja, R., Tsao, M. S., McPherson, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Robust+global+microRNA+expression+profiling+using+next-generation+sequencing+technologies.">Robust global microRNA expression profiling using next-generation sequencing technologies.</a> Lab. Invest. 94, 350-358 (2014).</li><li>Loudig, O., Wan, T., Ye, K., Lin, J., Wang, Y., Ramnauth, 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=Evaluation+and+Adaptation+of+a+Laboratory+Based+cDNA+Library+Preparation+Protocol+for+Retrospective+Sequencing+of+Archived+MicroRNAs+from+up+to+35-Year-Old+Clinical+FFPE+Specimens.">Evaluation and Adaptation of a Laboratory Based cDNA Library Preparation Protocol for Retrospective Sequencing of Archived MicroRNAs from up to 35-Year-Old Clinical FFPE Specimens.</a> Int J Mol Sci. 18, e627 (2017).</li><li>Kotorashvili, A., Ramnauth, A., Liu, C., Lin, J., Ye, K., Kim, R., 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=Effective+DNA/RNA+co-extraction+for+analysis+of+microRNAs,+mRNAs,+and+genomic+DNA+from+formalin-fixed+paraffin-embedded+specimens.">Effective DNA/RNA co-extraction for analysis of microRNAs, mRNAs, and genomic DNA from formalin-fixed paraffin-embedded specimens.</a> PLoS One. 7 (4), e34683 (2012).</li><li>Hafner, M., Renwick, N., Farazi, T. A., Mihailovi&#263;, A., Pena, J. T., Tuschl, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Barcoded+cDNA+library+preparation+for+small+RNA+profiling+by+next-generation+sequencing.">Barcoded cDNA library preparation for small RNA profiling by next-generation sequencing.</a> Methods. 58 (2), 164-170 (2012).</li><li>Loudig, O., Brandwein-Gensler, M., Kim, R. S., Lin, J., Isayeva, T., Liu, C., 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=Illumina+whole-genome+complementary+DNA-mediated+annealing,+selection,+extension+and+ligation+platform:+assessing+its+performance+in+formalin-fixed,+paraffin-embedded+samples+and+identifying+invasion+pattern-related+genes+in+oral+squamous+cell+carcinoma.">Illumina whole-genome complementary DNA-mediated annealing, selection, extension and ligation platform: assessing its performance in formalin-fixed, paraffin-embedded samples and identifying invasion pattern-related genes in oral squamous cell carcinoma.</a> Hum. Pathol. 42 (12), 1911-1922 (2011).</li></ol>

The authors wish to disclose that a publication containing some of the data presented in this manuscript was published in the International Journal of Molecular Sciences by Loudig et al.21.

A highly reproducible and robust cDNA library preparation protocol for NGS of small RNAs archived in FFPE RNA specimens is presented in this protocol, which is a modified and optimized version of the procedure described by Hafner et al.22
All steps of this protocol have been optimized for use with older archived and compromised total RNA recovered from FFPE specimens. The key step of this protocol, for processing small amounts of FFPE RNA, resides in the poolin...

miRNAs are remarkably well conserved in formalin-fixed paraffin-embedded (FFPE) specimens1,2,3. Previous work has demonstrated that the expression of these short regulatory non-coding single stranded RNA molecules can be successfully evaluated using total RNA from FFPE samples and provide relevant gene expression data when compared to the original fresh tissues4,5,6,7,8. When compared to large-size messenger RNAs, which have been shown to be critically affected by FFPE tissue processing (formaldehyde, heat, desiccation, etc.), endogenous RNases, and the age of the specimens, the small size of miRNAs (~18&#8211;24 nucleotides) appears to make them resistant to degradation and resilient to long-term storage, also demonstrated through miRNA expression studies that outperform high-throughput mRNA studies in archived specimens9. miRNA expression studies using archived clinical specimens, which have mostly been performed in small-scale analyses, have demonstrated that single or multiplexed quantitative PCR assays, different types of microarray technologies, and most recently NGS can be used to assess the expression of preserved miRNAs after optimization of these assays10,11,12,13,14.
Given that dysregulation of miRNA expression has been associated with the development of a variety of human malignancies and that there is potentially an enormous supply of clinically annotated archived specimens, it has become apparent that these small RNA molecules represent a promising source of potential cancer biomarkers15,16,17,18. The use of a high-throughput gene expression technology such as NGS has the advantage of providing a global evaluation of all miRNA transcripts when compared to targeted technologies such as PCR and/or microarrays19. For this reason, an optimized, affordable, and easily applicable protocol for cDNA library preparation of small RNAs from older archived specimens for NGS was optimized to enable large-scale retrospective studies20.
We previously established a simultaneous RNA/DNA extraction protocol for separate recovery of RNA and DNA from older archived specimens, which we found to outperform contemporary commercial kits21. Using this extraction protocol, to obtain total RNA from FFPE tissues archived for extended period of times, we optimized the preparation of cDNA libraries for NGS of miRNAs preserved in clinical specimens for up to 35 years. Furthermore, in a recently published study where we prepared cDNA libraries from clinically classified ductal carcinoma in situ (DCIS) specimens, we identified differentially expressed miRNAs that were validated by quantitative PCR, which indicated that specific miRNA expression changes may be detectable in DCIS lesions from patients who develop breast cancer when compared to DCIS lesions from patients who do not develop breast cancer.
Considering the cost of commercial kits for preparation of small RNA cDNA libraries, the potential for their discontinuation, as well as the use of copyright/patent-protected reagents that cannot be optimized, we decided to adapt a previously published laboratory-based and kit-free 3&#39; barcoded cDNA library preparation protocol for NGS of small RNAs archived in FFPE specimens, allowing simultaneous analysis of 18 samples22. This protocol provides an ideal and robust step-by-step procedure with visual and technical evaluation checkpoints, which were critical for adaptation to FFPE RNA specimens, and has a strong potential for application to other sources of compromised or difficult to use RNA material. The original protocol&#39;s applicability was improved by replacing radioactively labeled size markers with fluorescent (e.g., SYBR Gold) detectable RNA size markers used during selection of ligated libraries on large polyacrylamide gels. This optimized protocol relies on the ligation of 3&#39; barcoded adapters to 18 individual FFPE RNA specimens, which are then pooled together to undergo 5&#39; adapter ligation, reverse-transcription, and a pilot PCR analysis for tailored amplification of the final cDNA library prior to large-scale PCR amplification, purification, and NGS on a high throughput sequencer.

<table><tbody><tr><td>1% Triton x-100</td><td>Invitrogen</td><td>HFH10</td><td></td></tr><tr><td>10mM ATP</td><td>Ambion</td><td>AM8110G</td><td></td></tr><tr><td>10X dNTPs</td><td>Ambion</td><td>AM8110G</td><td></td></tr><tr><td>10x TBE</td><td>Thermofisher Scientific</td><td>15581044</td><td></td></tr><tr><td>14M Mercaptoethanol</td><td>Sigma</td><td>O3445I-100</td><td></td></tr><tr><td>20 nt ladder</td><td>Jena Bioscience</td><td>M-232S</td><td></td></tr><tr><td>20mg/ml Bovine Serum Albumine</td><td>Sigma</td><td>B8894-5ML</td><td></td></tr><tr><td>50X Titanium Taq</td><td>Clontech Laboratories</td><td>639208</td><td></td></tr><tr><td>Ammonium Persulfate</td><td>Fisher Scientific</td><td>7727-54-0</td><td></td></tr><tr><td>BRL Vertical Gel Electrophoresis System with glass plates and combs</td><td>GIBCO</td><td>V16</td><td></td></tr><tr><td>Dimethyl sulfoxide (DMSO)</td><td>Sigma</td><td>D9170-5VL</td><td></td></tr><tr><td>Eppendorf microcentrifuge 5424R</td><td>USA scientific</td><td>4054-4537Q</td><td></td></tr><tr><td>Eppndorf Thermomixer</td><td>USA scientific</td><td>4053-8223Q</td><td></td></tr><tr><td>Fisherbrand&amp;trade; Siliconized Low-Retention Microcentrifuge Tubes 1.5ml</td><td>Fisher Scientific</td><td>02-681-320</td><td></td></tr><tr><td>Gel Breaker Tube 0.5 ml</td><td>IST Engineering Inc,</td><td>3388-100</td><td></td></tr><tr><td>Gel electrophoresis apparatus 7cm x10cm- Mini-sub Cell GT with gel trays and combs</td><td>Biorad</td><td>1704446</td><td></td></tr><tr><td>Glycoblue</td><td>Ambion</td><td>AM9516</td><td></td></tr><tr><td>Jersey-Cote</td><td>LabScientific, Inc</td><td>1188</td><td></td></tr><tr><td>KcL 2M</td><td>Ambion</td><td>AM9640G</td><td></td></tr><tr><td>MgCl2 1M</td><td>Ambion</td><td>AM9530G</td><td></td></tr><tr><td>Minifuge dual rotor personal centrifuge</td><td>USA scientific</td><td>2641-0016</td><td></td></tr><tr><td>Model V16 polyacrylamide gel electrophoresis apparatus, glasses, combs, and spacers</td><td>Ciore Life Science</td><td>21070010</td><td></td></tr><tr><td>Oligonucleotides</td><td>IDT</td><td>Defined during order</td><td></td></tr><tr><td>Owl EasyCast B2 mini electrophoresis system- with gel trays and combs</td><td>Thermofisher Scientific</td><td>B2</td><td></td></tr><tr><td>Qiaquick Gel Extraction kit</td><td>Qiagen</td><td>28704</td><td></td></tr><tr><td>Restriction enzyme PmeI</td><td>NEB</td><td>R0560S</td><td></td></tr><tr><td>RNase-free water</td><td>Ambion</td><td>AM9932</td><td></td></tr><tr><td>Safe Imager 2.0</td><td>Life Technologies</td><td>G6600</td><td></td></tr><tr><td>Safe Imager 2.0 blue light transilluminator</td><td>Thermofisher</td><td>G6600</td><td></td></tr><tr><td>SeaKem LE agarose</td><td>Lonza</td><td>50002</td><td></td></tr><tr><td>Superscript III reverse transcription kit</td><td>Invitrogen</td><td>18080-044</td><td></td></tr><tr><td>SybrGold</td><td>Life Technologies</td><td>S11494</td><td></td></tr><tr><td>T4 RNA Ligase 1</td><td>NEB</td><td>M0204S</td><td></td></tr><tr><td>T4 RNA Ligase 2 Truncated K227Q</td><td>NEB</td><td>0351L</td><td></td></tr><tr><td>TEMED</td><td>Fisher Scientific</td><td>O3446I-100</td><td></td></tr><tr><td>Themocycler with heated lid</td><td>Applied Biosystem</td><td>4359659</td><td></td></tr><tr><td>Tris 1M pH 7.5</td><td>Invitrogen</td><td>15567027</td><td></td></tr><tr><td>Tris 1M pH8.0</td><td>Ambion</td><td>AM9855G</td><td></td></tr><tr><td>UltraPure Sequagel system concentrate, diluent, and buffer</td><td>National Diagnostics</td><td>EC-833</td><td></td></tr></tbody></table>

retrospective microrna sequencing: complementary dna library preparation protocol using formalin-fixed paraffin-embedded rna specimens

&#8211;Archived, clinically classified formalin-fixed paraffin-embedded (FFPE) tissues can provide nucleic acids for retrospective molecular studies of cancer development. By using non-invasive or pre-malignant lesions from patients who later develop invasive disease, gene expression analyses may help identify early molecular alterations that predispose to cancer risk. It has been well described that nucleic acids recovered from FFPE tissues have undergone severe physical damage and chemical modifications, which make their analysis difficult and generally requires adapted assays. MicroRNAs (miRNAs), however, which represent a small class of RNA molecules spanning only up to ~18&#8211;24 nucleotides, have been shown to withstand long-term storage and have been successfully analyzed in FFPE samples. Here we present a 3&#39; barcoded complementary DNA (cDNA) library preparation protocol specifically optimized for the analysis of small RNAs extracted from archived tissues, which was recently demonstrated to be robust and highly reproducible when using archived clinical specimens stored for up to 35 years. This library preparation is well adapted to the multiplex analysis of compromised/degraded material where RNA samples (up to 18) are ligated with individual 3&#39; barcoded adapters and then pooled together for subsequent enzymatic and biochemical preparations prior to analysis. All purifications are performed by polyacrylamide gel electrophoresis (PAGE), which allows size-specific selections and enrichments of barcoded small RNA species. This cDNA library preparation is well adapted to minute RNA inputs, as a pilot polymerase chain reaction (PCR) allows determination of a specific amplification cycle to produce optimal amounts of material for next-generation sequencing (NGS). This approach was optimized for the use of degraded FFPE RNA from specimens archived for up to 35 years and provides highly reproducible NGS data.

As described in the method here, a total of 18 individual FFPE RNA samples (100 ng each) are set up in separate tubes to undergo 3&#39; adenylated barcoded oligonucleotide T4 ligation overnight. The next day, the enzymatic reactions are heat-deactivated, combined, and precipitated in a single tube. The RNA pellet is resuspended and the ligated RNA molecules are separated on a 15% denaturing polyacrylamide gel (PAGE), where RNA oligonucleotide size markers that migrated in adjacent wells o...

Watch this Scientific Journal Video about Retrospective MicroRNA Sequencing: Complementary DNA Library Preparation Protocol Using Formalin-fixed Paraffin-embedded RNA Specimens at JoVE.com

Retrospective MicroRNA Sequencing: Complementary DNA Library Preparation Protocol Using Formalin-fixed Paraffin-embedded RNA Specimens

Formalin-fixed paraffin-embedded specimens represent a valuable source of molecular biomarkers of human diseases. Here we present a laboratory-based cDNA library preparation protocol, initially designed with fresh frozen RNA, and optimized for the analysis of archived microRNAs from tissues stored up to 35 years.

&#8211;Archived, clinically classified formalin-fixed paraffin-embedded (FFPE) tissues can provide nucleic acids for retrospective molecular studies of ...

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9.3K Views.  Hackensack University Medical Center. Formalin-fixed paraffin-embedded specimens represent a valuable source of molecular biomarkers of human diseases. Here we present a laboratory-based cDNA library preparation protocol, initially designed with fresh frozen RNA, and optimized for the analysis of archived microRNAs from tissues stored up to 35 years.

Video: Retrospective MicroRNA Sequencing: Complementary DNA Library Preparation Protocol Using Formalin-fixed Paraffin-embedded RNA Specimens

Isolating, Sequencing and Analyzing Extracellular MicroRNAs from Human Mesenchymal Stem Cells

Extracellular and circulating RNAs (exRNA) are produced by many cell types of the body and exist in numerous bodily fluids such as saliva, plasma, serum, milk and urine. One subset of these RNAs are the posttranscriptional regulators &#8211; microRNAs (miRNAs). To delineate the miRNAs produced by specific cell types, in vitro culture systems can be used to harvest and profile exRNAs derived from one subset of cells. The secreted factors of mesenchymal stem cells are implicated in alleviating numerous diseases and is used as the in vitro model system here. This paper describes the process of collection, purification of small RNA and library generation to sequence extracellular miRNAs. ExRNAs from culture media differ from cellular RNA by being low RNA input samples, which calls for optimized procedures. This protocol provides a comprehensive guide to small exRNA sequencing from culture media, showing quality control checkpoints at each step during exRNA purification and sequencing.

This protocol demonstrates how to purify extracellular microRNAs from cell culture media for small RNA library construction and next generation sequencing. Various quality control checkpoints are described to allow readers to understand what to expect when working with low input samples like exRNAs.

Extracellular and circulating RNAs (exRNA) are produced by many cell types of the body and exist in numerous bodily fluids such as saliva, plasma, serum, ...

A Complete Pipeline for Isolating and Sequencing MicroRNAs, and Analyzing Them Using Open Source Tools

Half of all human transcripts are thought to be regulated by microRNAs. Therefore, quantifying microRNA expression can reveal underlying mechanisms in disease states and provide therapeutic targets and biomarkers. Here, we detail how to accurately quantify microRNAs. Briefly, this method describes isolating microRNAs, ligating them to adaptors suitable for high-throughput sequencing, amplifying the final products, and preparing a sample library. Then, we explain how to align the obtained sequencing reads to microRNA hairpins, and quantify, normalize, and calculate their differential expression. Versatile and robust, this combined experimental workflow and bioinformatic analysis enables users to begin with tissue extraction and finish with microRNA quantification.

Here, we describe a step-by-step strategy for isolating small RNAs, enriching for microRNAs, and preparing samples for high-throughput sequencing. We then describe how to process sequence reads and align them to microRNAs, using open source tools.

Half of all human transcripts are thought to be regulated by microRNAs. Therefore, quantifying microRNA expression can reveal underlying mechanisms in ...

Identification of Circular RNAs using RNA Sequencing

Circular RNAs (circRNAs) are a class of non-coding RNAs involved in functions including micro-RNA (miRNA) regulation, mediation of protein-protein interactions, and regulation of parental gene transcription. In classical next generation RNA sequencing (RNA-seq), circRNAs are typically overlooked as a result of poly-A selection during construction of mRNA libraries, or are found at very low abundance, and are therefore difficult to isolate and detect. Here, a circRNA library construction protocol was optimized by comparing library preparation kits, pre-treatment options and various total RNA input amounts. Two commercially available whole transcriptome library preparation kits, with and without RNase R pre-treatment, and using variable amounts of total RNA input (1 to 4 &#181;g), were tested. Lastly, multiple tissue types; including liver, lung, lymph node, and pancreas; as well as multiple brain regions; including the cerebellum, inferior parietal lobe, middle temporal gyrus, occipital cortex, and superior frontal gyrus; were compared to evaluate circRNA abundance across tissue types. Analysis of the generated RNA-seq data using six different circRNA detection tools (find_circ, CIRI, Mapsplice, KNIFE, DCC, and CIRCexplorer) revealed that a stranded total RNA library preparation kit with RNase R pre-treatment and 4 &#181;g RNA input is the optimal method for identifying the highest relative number of circRNAs. Consistent with previous findings, the highest enrichment of circRNAs was observed in brain tissues compared to other tissue types.

Circular RNAs (circRNAs) are non-coding RNAs that may have roles in transcriptional regulation and mediating interactions between proteins. Following assessment of different parameters for construction of circRNA sequencing libraries, a protocol was compiled utilizing stranded total RNA library preparation with RNase R pre-treatment and is presented here.

Circular RNAs (circRNAs) are a class of non-coding RNAs involved in functions including micro-RNA (miRNA) regulation, mediation of protein-protein ...

Sequencing Small Non-coding RNA from Formalin-fixed Tissues and Serum-derived Exosomes from Castration-resistant Prostate Cancer Patients

Ablation of androgen receptor (AR) signaling by androgen deprivation is the goal of the first line of therapy for prostate cancer that initially results in cancer regression. However, in a significant number of cases, the disease progresses to advanced, castration-resistant prostate cancer (CRPC), which has limited therapeutic options and is often aggressive. Distant metastasis is mostly observed at this stage of the aggressive disease. CRPC is treated by a second generation of AR pathway inhibitors that improve survival initially, followed by the emergence of therapy resistance. Neuroendocrine prostate cancer (NEPC) is a rare variant of prostate cancer (PCa) that often develops as a result of therapy resistance via a transdifferentiation process known as neuroendocrine differentiation (NED), wherein PCa cells undergo a lineage switch from adenocarcinomas and show increased expression of neuroendocrine (NE) lineage markers. In addition to the genomic alterations that drive the progression and transdifferentiation to NEPC, epigenetic factors and microenvironmental cues are considered essential players in driving disease progression. This manuscript provides a detailed protocol to identify the epigenetic drivers (i.e., small non-coding RNAs) that are associated with advanced PCa. Using purified microRNAs from formalin-fixed paraffin-embedded (FFPE) metastatic tissues and corresponding serum-derived extracellular vesicles (EVs), the protocol describes how to prepare libraries with appropriate quality control for sequencing microRNAs from these sample sources. Isolating RNA from both FFPE and EVs is often challenging because most of it is either degraded or is limited in quantity. This protocol will elaborate on different methods to optimize the RNA inputs and cDNA libraries to yield most specific reads and high-quality data upon sequencing.

Therapy resistance often develops in patients with advanced prostate cancer, and in some cases, cancer progresses to a lethal subtype called neuroendocrine prostate cancer. Assessing the small non-coding RNA-mediated molecular changes that facilitate this transition would allow better disease stratification and identification of causal mechanisms that lead to development of neuroendocrine prostate cancer.

Ablation of androgen receptor (AR) signaling by androgen deprivation is the goal of the first line of therapy for prostate cancer that initially results ...

Cancer Research

Optimization for Sequencing and Analysis of Degraded FFPE-RNA Samples

Gene expression analysis by RNA sequencing (RNA-seq) enables unique insights into clinical samples that can potentially lead to mechanistic understanding of the basis of various diseases as well as resistance and/or susceptibility mechanisms. However, FFPE tissues, which represent the most common method for preserving tissue morphology in clinical specimens, are not the best sources for gene expression profiling analysis. The RNA obtained from such samples is often degraded, fragmented, and chemically modified, which leads to suboptimal sequencing libraries. In turn, these generate poor quality sequence data that may not be reliable for gene expression analysis and mutation discovery. In order to make the most of FFPE samples and obtain the best possible data from low quality samples, it is important to take certain precautions while planning experimental design, preparing sequencing libraries, and during data analysis. This includes the use of appropriate metrics for precise sample quality control (QC), identifying the best methods for various steps during the sequencing library generation, and careful library QC. In addition, applying correct software tools and parameters for sequence data analysis is critical in order to identify artifacts in RNA-seq data, filter out contamination and low quality reads, assess uniformity of gene coverage, and measure the reproducibility of gene expression profiles among biological replicates. These steps can ensure high accuracy and reproducibility for profiling of very heterogeneous RNA samples. Here we describe the various steps for sample QC, library preparation and QC, sequencing, and data analysis that can help to increase the amount of useful data obtained from low quality RNA, such as that obtained from FFPE-RNA tissues.

This method describes the steps to improve the quality and quantity of sequence data that can be obtained from formalin-fixed paraffin-embedded (FFPE) RNA samples. We describe the methodology to more accurately assess the quality of FFPE-RNA samples, prepare sequencing libraries, and analyze the data from FFPE-RNA samples.

Gene expression analysis by RNA sequencing (RNA-seq) enables unique insights into clinical samples that can potentially lead to mechanistic understanding ...

Preparation of Small RNA Libraries for Sequencing from Early Mouse Embryos

MicroRNAs (miRNAs) are important for the complex regulation of cell fate decisions and developmental timing. In vivo studies of the contribution of miRNAs during early development are technically challenging due to the limiting cell number. Moreover, many approaches require a miRNA of interest to be defined in assays such as northern blotting, microarray, and qPCR. Therefore, the expression of many miRNAs and their isoforms have not been studied during early development. Here, we demonstrate a protocol for small RNA sequencing of sorted cells from early mouse embryos to enable relatively unbiased profiling of miRNAs in early populations of neural crest cells. We overcome the challenges of low cell input and size selection during library preparation using amplification and gel-based purification. We identify embryonic age as a variable accounting for variation between replicates and stage-matched mouse embryos must be used to accurately profile miRNAs in biological replicates. Our results suggest that this method can be broadly applied to profile the expression of miRNAs from other lineages of cells. In summary, this protocol can be used to study how miRNAs regulate developmental programs in different cell lineages of the early mouse embryo.

We describe a technique for profiling microRNAs in early mouse embryos. This protocol overcomes the challenge of low cell input and small RNA enrichment. This assay can be used to analyze changes in miRNA expression over time in different cell lineages of the early mouse embryo.

MicroRNAs (miRNAs) are important for the complex regulation of cell fate decisions and developmental timing. In vivo studies of the contribution of miRNAs ...

Developmental Biology

Single Read and Paired End mRNA-Seq Illumina Libraries from 10 Nanograms Total RNA

Whole transcriptome sequencing by mRNA-Seq is now used extensively to perform global gene expression, mutation, allele-specific expression and other genome-wide analyses. mRNA-Seq even opens the gate for gene expression analysis of non-sequenced genomes. mRNA-Seq offers high sensitivity, a large dynamic range and allows measurement of transcript copy numbers in a sample. Illumina&#x2019;s genome analyzer performs sequencing of a large number (&gt; 107) of relatively short sequence reads (&lt; 150 bp).The &quot;paired end&quot; approach, wherein a single long read is sequenced at both its ends, allows for tracking alternate splice junctions, insertions and deletions, and is useful for de novo transcriptome assembly.
One of the major challenges faced by researchers is a limited amount of starting material. For example, in experiments where cells are harvested by laser micro-dissection, available starting total RNA may measure in nanograms. Preparation of mRNA-Seq libraries from such samples have been described1, 2 but involves significant PCR amplification that may introduce bias. Other RNA-Seq library construction procedures with minimal PCR amplification have been published3, 4 but require microgram amounts of starting total RNA.
Here we describe a protocol for the Illumina Genome Analyzer II platform for mRNA-Seq sequencing for library preparation that avoids significant PCR amplification and requires only 10 nanograms of total RNA. While this protocol has been described previously and validated for single-end sequencing5, where it was shown to produce directional libraries without introducing significant amplification bias, here we validate it further for use as a paired end protocol. We selectively amplify polyadenylated messenger RNAs from starting total RNA using the T7 based Eberwine linear amplification method, coined &quot;T7LA&quot; (T7 linear amplification). The amplified poly-A mRNAs are fragmented, reverse transcribed and adapter ligated to produce the final sequencing library. For both single read and paired end runs, sequences are mapped to the human transcriptome6 and normalized so that data from multiple runs can be compared. We report the gene expression measurement in units of transcripts per million (TPM), which is a superior measure to RPKM when comparing samples7.

Here we describe a method for preparation of both single read and paired end Illumina mRNA-Seq sequencing libraries for gene expression analysis based on T7 linear RNA amplification. This protocol requires only 10 nanograms of starting total RNA and generates highly consistent libraries representing whole transcripts.

Whole transcriptome sequencing by mRNA-Seq is now used extensively to perform global gene expression, mutation, allele-specific expression and other ...

Biology

Highly Efficient Ligation of Small RNA Molecules for MicroRNA Quantitation by High-Throughput Sequencing

MiRNA cloning and high-throughput sequencing, termed miR-Seq, stands alone as a transcriptome-wide approach to quantify miRNAs with single nucleotide resolution. This technique captures miRNAs by attaching 3&#8217; and 5&#8217; oligonucleotide adapters to miRNA molecules and allows de novo miRNA discovery. Coupling with powerful next-generation sequencing platforms, miR-Seq has been instrumental in the study of miRNA biology. However, significant biases introduced by oligonucleotide ligation steps have prevented miR-Seq from being employed as an accurate quantitation tool. Previous studies demonstrate that biases in current miR-Seq methods often lead to inaccurate miRNA quantification with errors up to 1,000-fold for some miRNAs1,2. To resolve these biases imparted by RNA ligation, we have developed a small RNA ligation method that results in ligation efficiencies of over 95% for both 3&#8217; and 5&#8242; ligation steps. Benchmarking this improved library construction method using equimolar or differentially mixed synthetic miRNAs, consistently yields reads numbers with less than two-fold deviation from the expected value. Furthermore, this high-efficiency miR-Seq method permits accurate genome-wide miRNA profiling from in vivo total RNA samples2.

MicroRNAs (miRNAs) are a widely conserved class of regulatory molecules. Here we describe a miRNA cloning method that relies upon two potent ligation steps followed by high-throughput sequencing. Our method permits accurate genome-wide quantitation of miRNAs.

MiRNA cloning and high-throughput sequencing, termed miR-Seq, stands alone as a transcriptome-wide approach to quantify miRNAs with single nucleotide ...

Targeted RNA Sequencing Assay to Characterize Gene Expression and Genomic Alterations

RNA sequencing (RNAseq) is a versatile method that can be utilized to detect and characterize gene expression, mutations, gene fusions, and noncoding RNAs. Standard RNAseq requires 30 - 100 million sequencing reads and can include multiple RNA products such as mRNA and noncoding RNAs. We demonstrate how targeted RNAseq (capture) permits a focused study on selected RNA products using a desktop sequencer. RNAseq capture can characterize unannotated, low, or transiently expressed transcripts that may otherwise be missed using traditional RNAseq methods. Here we describe the extraction of RNA from cell lines, ribosomal RNA depletion, cDNA synthesis, preparation of barcoded libraries, hybridization and capture of targeted transcripts and multiplex sequencing on a desktop sequencer. We also outline the computational analysis pipeline, which includes quality control assessment, alignment, fusion detection, gene expression quantification and identification of single nucleotide variants. This assay allows for targeted transcript sequencing to characterize gene expression, gene fusions, and mutations.

We describe a targeted RNA sequencing-based method that includes preparation of indexed cDNA libraries, hybridization and capture with custom probes and data analysis to interrogate selected transcripts for gene expression, mutations, and gene fusions. Targeted RNAseq permits cost-effective, rapid evaluation of selected transcripts on a desktop sequencer.

RNA sequencing (RNAseq) is a versatile method that can be utilized to detect and characterize gene expression, mutations, gene fusions, and noncoding ...

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 ...