Name: oncogenic gene fusion detection using anchored multiplex polymerase chain reaction followed by next generation sequencing
Uploaded: 2019-07-05T14:00:00
Description: Watch this Scientific Journal Video about Oncogenic Gene Fusion Detection Using Anchored Multiplex Polymerase Chain Reaction Followed by Next Generation Sequencing at JoVE.com

This work was supported by the Molecular Pathology Shared Resource of the University of Colorado (National Cancer Institute Cancer Center Support Grant No. P30-CA046934) and by the Colorado Center for Personalized Medicine.

1. Library preparation and sequencing
<ol>
	<li>General assay considerations and pre-assay steps
	<ol>
		<li>Assay runs typically consist of seven clinical samples and one positive control (although the number of samples per library preparation run can be adjusted as necessary). Use a positive control that contains at least several gene fusions (that the assay targets) that have been confirmed by a manufacturer and/or have been confirmed by an orthogonal methodology. A non-template control (NTC) must b...

<ol>
	<li>Mitelman, F., Johansson, B., Mertens, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+impact+of+translocations+and+gene+fusions+on+cancer+causation.">The impact of translocations and gene fusions on cancer causation.</a> Nature Reviews Cancer. 7 (4), 233-245 (2007).</li><li>Daley, G. Q., Van Etten, R. A., Baltimore, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+chronic+myelogenous+leukemia+in+mice+by+the+P210bcr/abl+gene+of+the+Philadelphia+chromosome.">Induction of chronic myelogenous leukemia in mice by the P210bcr/abl gene of the Philadelphia chromosome.</a> Science. 247 (4944), 824-830 (1990).</li><li>Druker, B. 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=Activity+of+a+specific+inhibitor+of+the+BCR-ABL+tyrosine+kinase+in+the+blast+crisis+of+chronic+myeloid+leukemia+and+acute+lymphoblastic+leukemia+with+the+Philadelphia+chromosome.">Activity of a specific inhibitor of the BCR-ABL tyrosine kinase in the blast crisis of chronic myeloid leukemia and acute lymphoblastic leukemia with the Philadelphia chromosome.</a> New England Journal of Medicine. 344 (14), 1038-1042 (2001).</li><li>Solomon, B. 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=First-line+crizotinib+versus+chemotherapy+in+ALK-positive+lung+cancer.">First-line crizotinib versus chemotherapy in ALK-positive lung cancer.</a> New England Journal of Medicine. 371 (23), 2167-2177 (2014).</li><li>Shaw, A. T., 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=Crizotinib+in+ROS1-rearranged+non-small-cell+lung+cancer.">Crizotinib in ROS1-rearranged non-small-cell lung cancer.</a> New England Journal of Medicine. 371 (21), 1963-1971 (2014).</li><li>Drilon, 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=Efficacy+of+Larotrectinib+in+TRK+Fusion-Positive+Cancers+in+Adults+and+Children.">Efficacy of Larotrectinib in TRK Fusion-Positive Cancers in Adults and Children.</a> New England Journal of Medicine. 378 (8), 731-739 (2018).</li><li>Kawai, 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=SYT-SSX+gene+fusion+as+a+determinant+of+morphology+and+prognosis+in+synovial+sarcoma.">SYT-SSX gene fusion as a determinant of morphology and prognosis in synovial sarcoma.</a> New England Journal of Medicine. 338 (3), 153-160 (1998).</li><li>de Alava, E., 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=EWS-FLI1+fusion+transcript+structure+is+an+independent+determinant+of+prognosis+in+Ewing's+sarcoma.">EWS-FLI1 fusion transcript structure is an independent determinant of prognosis in Ewing's sarcoma.</a> Journal of Clinical Oncology. 16 (4), 1248-1255 (1998).</li><li>Pierron, 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=A+new+subtype+of+bone+sarcoma+defined+by+BCOR-CCNB3+gene+fusion.">A new subtype of bone sarcoma defined by BCOR-CCNB3 gene fusion.</a> Nature Genetics. 44 (4), 461-466 (2012).</li><li>Papaemmanuil, E., 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=Genomic+Classification+and+Prognosis+in+Acute+Myeloid+Leukemia.">Genomic Classification and Prognosis in Acute Myeloid Leukemia.</a> New England Journal of Medicine. 374 (23), 2209-2221 (2016).</li><li>Arber, D. 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=The+2016+revision+to+the+World+Health+Organization+classification+of+myeloid+neoplasms+and+acute.">The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute.</a> Blood. 127 (20), 2391-2405 (2016).</li><li>Sanders, H. 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=Exon+scanning+by+reverse+transcriptase-polymerase+chain+reaction+for+detection+of+known+and+novel+EML4-ALK+fusion+variants+in+non-small+cell+lung+cancer.">Exon scanning by reverse transcriptase-polymerase chain reaction for detection of known and novel EML4-ALK fusion variants in non-small cell lung cancer.</a> Cancer Genetics. 204 (1), 45-52 (2011).</li><li>Camidge, D. 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=Optimizing+the+Detection+of+Lung+Cancer+Patients+Harboring+Anaplastic+Lymphoma+Kinase+(ALK)+Gene+Rearrangements+Potentially+Suitable+for+ALK+Inhibitor+Treatment.">Optimizing the Detection of Lung Cancer Patients Harboring Anaplastic Lymphoma Kinase (ALK) Gene Rearrangements Potentially Suitable for ALK Inhibitor Treatment.</a> Clinical Cancer Research. 16 (22), 5581-5590 (2010).</li><li>Mino-Kenudson, 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=A+novel,+highly+sensitive+antibody+allows+for+the+routine+detection+of+ALK-rearranged+lung+adenocarcinomas+by+standard+immunohistochemistry.">A novel, highly sensitive antibody allows for the routine detection of ALK-rearranged lung adenocarcinomas by standard immunohistochemistry.</a> Clinical Cancer Research. 16 (5), 1561-1571 (2010).</li><li>Suehara, Y., 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=Identification+of+KIF5B-RET+and+GOPC-ROS1+fusions+in+lung+adenocarcinomas+through+a+comprehensive+mRNA-based+screen+for+tyrosine+kinase+fusions.">Identification of KIF5B-RET and GOPC-ROS1 fusions in lung adenocarcinomas through a comprehensive mRNA-based screen for tyrosine kinase fusions.</a> Clinical Cancer Research. 18 (24), 6599-6608 (2012).</li><li>Davies, K. 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=Comparison+of+Molecular+Testing+Modalities+for+Detection+of+ROS1+Rearrangements+in+a+Cohort+of+Positive+Patient+Samples.">Comparison of Molecular Testing Modalities for Detection of ROS1 Rearrangements in a Cohort of Positive Patient Samples.</a> Journal of Thoracic Oncology. 13 (10), 1474-1482 (2018).</li><li>Reeser, J. W., 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=Validation+of+a+Targeted+RNA+Sequencing+Assay+for+Kinase+Fusion+Detection+in+Solid+Tumors.">Validation of a Targeted RNA Sequencing Assay for Kinase Fusion Detection in Solid Tumors.</a> Journal of Molecular Diagnostics. 19 (5), 682-696 (2017).</li><li>Beadling, 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=A+Multiplexed+Amplicon+Approach+for+Detecting+Gene+Fusions+by+Next-Generation+Sequencing.">A Multiplexed Amplicon Approach for Detecting Gene Fusions by Next-Generation Sequencing.</a> Journal of Molecular Diagnostics. 18 (2), 165-175 (2016).</li><li>Mamanova, L., 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=Target-enrichment+strategies+for+next-generation+sequencing.">Target-enrichment strategies for next-generation sequencing.</a> Nature Methods. 7 (2), 111-118 (2010).</li><li>Zheng, Z., 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=Anchored+multiplex+PCR+for+targeted+next-generation+sequencing.">Anchored multiplex PCR for targeted next-generation sequencing.</a> Nature Medicine. 20 (12), 1479-1484 (2014).</li><li>Davies, K. 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=Dramatic+Response+to+Crizotinib+in+a+Patient+with+Lung+Cancer+Positive+for+an+HLA-DRB1-MET+Gene+Fusion.">Dramatic Response to Crizotinib in a Patient with Lung Cancer Positive for an HLA-DRB1-MET Gene Fusion.</a> JCO Precision Oncology. 2017 (1), (2017).</li><li>Vendrell, J. 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=Detection+of+known+and+novel+ALK+fusion+transcripts+in+lung+cancer+patients+using+next-generation+sequencing+approaches.">Detection of known and novel ALK fusion transcripts in lung cancer patients using next-generation sequencing approaches.</a> Scientific Reports. 7 (1), 12510 (2017).</li><li>Agaram, N. P., Zhang, L., Cotzia, P., Antonescu, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expanding+the+Spectrum+of+Genetic+Alterations+in+Pseudomyogenic+Hemangioendothelioma+With+Recurrent+Novel+ACTB-FOSB+Gene+Fusions.">Expanding the Spectrum of Genetic Alterations in Pseudomyogenic Hemangioendothelioma With Recurrent Novel ACTB-FOSB Gene Fusions.</a> American Journal of Surgical Pathology. 42 (12), 1653-1661 (2018).</li><li>Skalova, 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=Molecular+Profiling+of+Mammary+Analog+Secretory+Carcinoma+Revealed+a+Subset+of+Tumors+Harboring+a+Novel+ETV6-RET+Translocation:+Report+of+10+Cases.">Molecular Profiling of Mammary Analog Secretory Carcinoma Revealed a Subset of Tumors Harboring a Novel ETV6-RET Translocation: Report of 10 Cases.</a> American Journal of Surgical Pathology. 42 (2), 234-246 (2018).</li><li>Guseva, N. V., 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=Anchored+multiplex+PCR+for+targeted+next-generation+sequencing+reveals+recurrent+and+novel+USP6+fusions+and+upregulation+of+USP6+expression+in+aneurysmal+bone+cyst.">Anchored multiplex PCR for targeted next-generation sequencing reveals recurrent and novel USP6 fusions and upregulation of USP6 expression in aneurysmal bone cyst.</a> Genes Chromosomes and Cancer. 56 (4), 266-277 (2017).</li></ol>

Anchored multiplex PCR-based target enrichment and library preparation followed by next-generation sequencing is well suited for multiplexed gene fusion assessment in clinical tumor samples. By focusing on RNA input rather than genomic DNA, the need to sequence large and repetitive introns is avoided. Additionally, since this approach amplifies gene fusions regardless of the identity of the fusion partner, novel fusions are detected. This is a critical advantage in the clinical realm, and there have been many examples of...

The fusion of two or more genes into a single transcriptional entity can occur as the result of large scale chromosomal variations including deletions, duplications, insertions, inversions, and translocations. Through altered transcriptional control and/or altered functional properties of the expressed gene product, these fusion genes can confer oncogenic properties to cancer cells1. In many cases, fusion genes are known to act as primary oncogenic drivers by directly activating cellular proliferation and survival pathways.
The clinical relevance of gene fusions for cancer patients first became apparent with the discovery of the Philadelphia chromosome and the corresponding BCR-ABL1 fusion gene in chronic myelogenous leukemia (CML)2. The small molecule inhibitor imatinib mesylate was developed to specifically target this fusion gene and demonstrated remarkable efficacy in BCR-ABL1-positive CML patients3. Therapeutic targeting of oncogenic gene fusions has also been successful in solid tumors, with inhibition of ALK and ROS1 fusion genes in non-small cell lung cancer serving as primary examples4,5. Recently, the NTRK inhibitor larotrectinib was FDA approved for NTRK1/2/3 fusion-positive solid tumors, regardless of disease site6. Beyond therapy selection, gene fusion detection also has roles in disease diagnosis and prognosis. This is particularly prevalent in various sarcoma and hematologic malignancy subtypes that are diagnostically defined by the presence of specific fusions and/or for which presence of a fusion directly informs prognosis7,8,9,10,11. These are but a few of the examples of the clinical application of gene fusion detection for cancer patients.
Due to the critical role in clinical decision making, accurate gene fusion detection from clinical samples is of vital importance. Numerous techniques have been applied in clinical laboratories for fusion or chromosomal rearrangement analysis including: cytogenetic techniques, reverse transcription polymerase chain reaction (RT-PCR), fluorescence in situ hybridization (FISH), immunohistochemistry (IHC), and 5&#8217;/3&#8217; expression imbalance analysis (among others)12,13,14,15. Presently, the rapidly expanding list of actionable gene fusions in cancer has resulted in the need to assess fusion status of multiple genes simultaneously. Consequently, some traditional techniques that can only query one or a few genes at a time are becoming inefficient approaches, especially when considering that clinical tumor samples are often very finite and not amenable to being divided among several assays. Next generation sequencing (NGS), however, is an analysis platform that is well suited for multi-gene testing, and NGS-based assays have become common in clinical molecular diagnostic laboratories.
Currently used NGS assays for fusion/rearrangement detection vary in regard to the input material used, the chemistries employed for library preparation and target enrichment, and the number of genes queried within an assay. NGS assays can be based on RNA or DNA (or both) extracted from the sample. Although RNA-based analysis is hampered by the tendency of clinical samples to contain highly degraded RNA, it circumvents the need to sequence large and often repetitive introns that are the targets of DNA-based fusion testing but have proven to be difficult for NGS data analysis16. Target enrichment strategies for RNA-based NGS assays can be largely divided into hybrid capture or amplicon-mediated approaches. While both strategies have been successfully utilized for fusion detection, each contains advantages over the other17,18. Hybrid capture assays generally result in more complex libraries and reduced allelic dropout, whereas amplicon-based assays generally require lower input and result in less off-target sequencing19. However, perhaps the primary limitation of traditional amplicon-based enrichment is the need for primers to all known fusion partners. This is problematic since many clinically important genes are known to fuse with dozens of different partners, and even if primer design allowed for detection of all known partners, novel fusion events would remain undetected. A recently described technique termed anchored multiplex PCR (or AMP for short) addresses this limitation20. In AMP, a &#8216;half-functional&#8217; NGS adapter is ligated to cDNA fragments that are derived from input RNA. Target enrichment is achieved by amplification between gene specific primers and a primer to the adapter. As a result, all fusions to genes of interest, even if a novel fusion partner is involved, should be detected (see Figure 1). This article describes the use of the ArcherDx FusionPlex Solid Tumor kit, an NGS-based assay that employs AMP for target enrichment and library preparation, for the detection of oncogenic gene fusions in solid tumor samples (see Supplementary Table 1 for complete gene list). The wet-bench protocol and data analysis steps have been rigorously validated in a Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory.

<table>
	<tbody>
		<tr>
			<td>10 mM Tris HCl pH 8.0</td>
			<td>IDT</td>
			<td>11-05-01-13</td>
			<td>Used for TNA dilution</td>
		</tr>
		<tr>
			<td>1M Tris pH 7.0</td>
			<td>Thermo Fisher</td>
			<td>AM9850G</td>
			<td>Used in library pooling</td>
		</tr>
		<tr>
			<td>25 mL Reagent Reservoir with divider</td>
			<td>USA Scientific</td>
			<td>9173-2000</td>
			<td>For use with multi-channel pipetters and large reagent volumes</td>
		</tr>
		<tr>
			<td>96-well TemPlate Semi-Skirt 0.1mL PCR plate-natural</td>
			<td>USA Scientific</td>
			<td>1402-9700</td>
			<td>Plate used for thermocycler steps</td>
		</tr>
		<tr>
			<td>Agencourt AMPure XP Beads</td>
			<td>Beckman Coulter</td>
			<td>A63881</td>
			<td>Used in purification after several assay steps</td>
		</tr>
		<tr>
			<td>Agencourt Formapure Kit</td>
			<td>Beckman Coulter</td>
			<td>A33343</td>
			<td>Used in TNA extraction</td>
		</tr>
		<tr>
			<td>Archer FusionPlex Solid Tumor kit</td>
			<td>ArcherDX</td>
			<td>AB0005</td>
			<td>This kit contains most of the reagents necessary to perform library preperation for Illumina sequencing (kits for Ion Torrent sequencing are also available)</td>
		</tr>
		<tr>
			<td>Cold block, 96-well</td>
			<td>Light Labs</td>
			<td>A7079</td>
			<td>Used for keeping samples chilled at various steps</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Decon Labs</td>
			<td>DSP-MD.43</td>
			<td>Used for bead washes</td>
		</tr>
		<tr>
			<td>Library Quantification for Illumina Internal Control Standard</td>
			<td>Kapa Biosystems</td>
			<td>KK4906</td>
			<td>Used for library quantitation</td>
		</tr>
		<tr>
			<td>Library Quantification Primers and ROX Low qPCR mix</td>
			<td>Kapa Biosystems</td>
			<td>KK4973</td>
			<td>Used for library quantitation</td>
		</tr>
		<tr>
			<td>Library Quantification Standards</td>
			<td>Kapa Biosystems</td>
			<td>KK4903</td>
			<td>Used for library quantitation</td>
		</tr>
		<tr>
			<td>Magnet Plate, 96-well (N38 grade)</td>
			<td>Alpaqua</td>
			<td>A32782</td>
			<td>Used in bead purificiation steps</td>
		</tr>
		<tr>
			<td>MBC Adapters Set B</td>
			<td>ArcherDX</td>
			<td>AK0016-48</td>
			<td>Adapters that contain sample-specific indexes to enable multiplex sequencing</td>
		</tr>
		<tr>
			<td>Micro Centrifuge</td>
			<td>USA Scientific</td>
			<td>2641-0016</td>
			<td>Used for spinning down PCR tubes</td>
		</tr>
		<tr>
			<td>MicroAmp EnduraPlate Optical 96 well Plate</td>
			<td>Thermo-Fisher</td>
			<td>4483485</td>
			<td>Used for Pre-Seq QClibrary quantitation</td>
		</tr>
		<tr>
			<td>Microamp Optical Film Compression Pad</td>
			<td>Applied Biosystems</td>
			<td>4312639</td>
			<td>Used for library quantitation</td>
		</tr>
		<tr>
			<td>Mini Plate Spinner</td>
			<td>Labnet</td>
			<td>MPS-1000</td>
			<td>Used for collecing liquid at bottom of plate wells</td>
		</tr>
		<tr>
			<td>MiSeq Reagent Kit v3 (600 cycle)</td>
			<td>Illumina</td>
			<td>MS-102-3003</td>
			<td>Contains components necessary for a MiSeq sequencing run</td>
		</tr>
		<tr>
			<td>MiSeqDx System</td>
			<td>Illumina</td>
			<td></td>
			<td>NGS Sequencing Instrument</td>
		</tr>
		<tr>
			<td>Model 9700 Thermocycler</td>
			<td>Applied Biosystems</td>
			<td></td>
			<td>Used for several steps during assay</td>
		</tr>
		<tr>
			<td>nuclease free water</td>
			<td>Ambion</td>
			<td>9938</td>
			<td>Used as general diluent</td>
		</tr>
		<tr>
			<td>Optical ABI 96-well PCR plate covers</td>
			<td>Thermo-Fisher</td>
			<td>4311971</td>
			<td>Used for Pre-Seq QClibrary quantitation</td>
		</tr>
		<tr>
			<td>PCR Workstation Model 600</td>
			<td>Air Clean Systems</td>
			<td>BZ10119636</td>
			<td>Wet-bench assay steps performed in this &#39;dead air box&#39;</td>
		</tr>
		<tr>
			<td>Proteinase K</td>
			<td>Qiagen</td>
			<td>1019499</td>
			<td>Used in TNA extraction</td>
		</tr>
		<tr>
			<td>QuantStudio 5</td>
			<td>Applied Biosystems</td>
			<td>LSA28139</td>
			<td>qPCR instrument used for PreSeq and library quantitation</td>
		</tr>
		<tr>
			<td>Qubit RNA HS Assay Kit</td>
			<td>Life Technologies</td>
			<td>Q32855</td>
			<td>Use for determing RNA concentration in TNA samples</td>
		</tr>
		<tr>
			<td>RNase Away</td>
			<td>Fisher</td>
			<td>12-402-178</td>
			<td>Used for general RNase decontamination of work areas</td>
		</tr>
		<tr>
			<td>Seraseq FFPE Tumor Fusion RNA Reference Material v2</td>
			<td>SeraCare</td>
			<td>0710-0129</td>
			<td>Used as the assay positive control</td>
		</tr>
		<tr>
			<td>Sodium Hydroxide</td>
			<td>Fisher</td>
			<td>BP359-212</td>
			<td>Used in clean-up steps and for sequencing setup</td>
		</tr>
		<tr>
			<td>SYBR Green Supermix</td>
			<td>Bio Rad</td>
			<td>172-5120</td>
			<td>Component of PreSeq QC Assay</td>
		</tr>
		<tr>
			<td>TempAssure PCR 8-tube Strips</td>
			<td>USA Scientific</td>
			<td>1402-2700</td>
			<td>Used for reagent and sample mixing etc.</td>
		</tr>
		<tr>
			<td>Template RT PCR film</td>
			<td>USA Scientific</td>
			<td>2921-7800</td>
			<td>Used for covering 96-well plates</td>
		</tr>
		<tr>
			<td>U-Bottom 96-well Microplate</td>
			<td>LSP</td>
			<td>MP8117-R</td>
			<td>Used during bead purification</td>
		</tr>
	</tbody>
</table>

oncogenic gene fusion detection using anchored multiplex polymerase chain reaction followed by next generation sequencing

Gene fusions frequently contribute to the oncogenic phenotype of many different types of cancer. Additionally, the presence of certain fusions in samples from cancer patients often directly influences diagnosis, prognosis, and/or therapy selection. As a result, the accurate detection of gene fusions has become a critical component of clinical management for many disease types. Until recently, clinical gene fusion detection was predominantly accomplished through the use of single-gene assays. However, the ever-growing list of gene fusions with clinical significance has created a need for assessing fusion status of multiple genes simultaneously. Next generation sequencing (NGS)-based testing has met this demand through the ability to sequence nucleic acid in massively parallel fashion. Multiple NGS-based approaches that employ different strategies for gene target enrichment are now available for use in clinical molecular diagnostics, each with its own strengths and weaknesses. This article describes the use of anchored multiplex PCR (AMP)-based target enrichment and library preparation followed by NGS to assess for gene fusions in clinical solid tumor specimens. AMP is unique among amplicon-based enrichment approaches in that it identifies gene fusions regardless of the identity of the fusion partner. Detailed here are both the wet-bench and data analysis steps that ensure accurate gene fusion detection from clinical samples.

Shown in Figure 3, Figure 4 and Figure 5 are screenshots from the analysis user interface demonstrating results from a lung adenocarcinoma sample. In Figure 3, the sample summary is shown (top) that lists the called strong evidence fusions, as well as the QC status (circled in red). The ADCK4-NUMBL fusion (of which 3 isoforms are listed) is immediately ignored because it is a persistent transcr...

Watch this Scientific Journal Video about Oncogenic Gene Fusion Detection Using Anchored Multiplex Polymerase Chain Reaction Followed by Next Generation Sequencing at JoVE.com

Oncogenic Gene Fusion Detection Using Anchored Multiplex Polymerase Chain Reaction Followed by Next Generation Sequencing

This article details the use of an anchored multiplex polymerase chain reaction-based library preparation kit followed by next-generation sequencing to assess for oncogenic gene fusions in clinical solid tumor samples. Both wet-bench and data analysis steps are described.

Gene fusions frequently contribute to the oncogenic phenotype of many different types of cancer. Additionally, the presence of certain fusions in samples ...

This protocol is used for the detection of critically informative gene fusions for patient tumor samples. The fusion status of dozens of genes is assessed simultaneously in a single assay. The advantage of this technique is that I can identify gene fusions regardless of the identity of the fusion partner from tumor samples that have been processed by formulative fixation.The detection of certain gene fusion in clinical tumor sample directly informs diagnosis, prognosis and treatment selection in many cancer types. It is critical to understand that many fusions called by the analysis algorithm are artifacts. The most difficult task when analyzing data is distinguishing between artifact and real fusion calls.Begin by diluting total nucleic acid to achieve the desired concentration of RNA. For each sample, transfer 20 microliters of the dilution into the random priming reagent strip tubes in a pre-chilled aluminum block and mix by pipetting up and down six to eight times. Briefly spin down the samples, transfer the entire volume to a 96-well PCR plate, and seal with plate sealer film.Insert the plate into a thermocycler, cover with the compression pad, and close the lid. Incubate at 65 degree Celsius for five minutes. After the incubation, transfer the entire volume of the random priming product in the first strand reagent strip tubes.Mix by pipetting up and down and briefly spin down. Transfer the entire volume to a 96-well PCR plate and seal with RT film. Insert the plate into the thermocycler and run the reaction according to the manuscript directions.Perform second strand cDNA synthesis, and repair, and ligation step one according to the manuscript directions and proceed to the second ligation step. To number the molecular barcode or MBC adapter strip tubes, position the tubes horizontally with hinges to the back and use a permanent marker. Take the bead purification plate from the first ligation step and transfer 40 microliters of each sample into the MBC adapter strip tubes, taking care not to disturb the bead pellet.Mix the reagents by pipetting, spin down the tubes, and transfer the entire volume to the ligation step two reagent strip tubes. Mix the samples, spin them down, and place in a thermocycler block. Leave the heated lid off and run the thermocycler at 22 degrees Celsius for five minutes, followed by 4 degrees Celsius hold.Next, prepare the ligation cleanup beads by vortexing them and adding 50 microliters to a new set of PCR strip tubes. Incubate on the magnet for one minute and discard the supernatant. Remove the strip tubes from the magnet and resuspend the beads in 50 microliters of ligation cleanup buffer by pipetting up and down.Transfer the entire sample volume from the second ligation step into the ligation cleanup bead strip. Vortex the samples to mix and leave them at room temperature for 10 minutes. Vortex the sample once halfway through the incubation.Afterwards, vortex the samples, spin them down, and incubate on the magnet for one minute. Discard the supernatant and add 200 microliters of fresh ligation cleanup buffer. Vortex to resuspend, spin down, and place on the magnet for one minute.After the two washes, perform a third wash using ultrapure water instead of buffer. Resuspend the beads in 20 microliters of 5 millimeters sodium hydroxide and transfer the samples to a 96-well PCR plate. Place the plate into a thermocycler with a compression pad and run it at 75 degrees Celsius for 10 minutes, followed by a 4 degrees Celsius hold.Once the samples have cooled to 4 degrees Celsius, place the plate on a magnet for at least three minutes and proceed with the first PCR. Prepare the PCR reactions by adding two microliters of GSP1 primers to each well of the first PCR reagent strip. Transfer 18 microliters of the second ligation cleanup product to the first PCR reagent strip tubes and mix by pipetting up and down.Spin down the samples and transfer them to a 96-well PCR plate. Place them into the thermocycler and run PCR according to the manuscript directions. Proceed with bead purification by adding 20 microliters of the PCR product to a U-bottom plate filled with 24 microliters of purification beads per well.Pipette up and down to mix and leave the plate at room temperature for five minutes, then incubate the plate on the magnet for two minutes. Discard the supernantant from the beads and wash them twice with 200 microliters of 70%ethanol. After the final wash, remove all of the ethanol and let the sample air dry for two minutes.Remove the plate from the magnet and resuspend the beads in 24 microliters of 10 millimeter Tris-HCl and pH 8.0. Incubate off the magnet for three minutes and then place the plate back on the magnet for two minutes. Begin library quantitation by preparing one to five dilutions of the second PCR product in 10 millimeter Tris-HCl.Follow this by a serial dilution of 1:199, 1:199, and 20:80 in 10 millimeter Tris-HCl with 05%polysorbate. Set up key PCR by adding six microliters of master mix to each well of a optical 96-well plate, followed by four microliters of the appropriate dilution or standard. Spin down the plate and load it into the qPCR instrument.Perform qPCR according to the manuscript directions. After library quantification is complete, dilute all libraries to two nanomolar with 10 millimeter Tris-HCl. Make a library pool by combining 10 microliters of each normalized library into one 1.5 milliliter microcentrifuge tube.Next, prepare the denatured amplicon library, or DAL pool, by combining 10 microliters of the library pool with 10 microliters of 0.2 normal sodium hydroxide and incubating the mixture for five minutes at room temperature. After the incubation, add 10 microliters of 200 millimeter Tris-HCl at pH 7.0, followed by 970 microliters of HT1 Hybridization Buffer. Make the final load tube by combining 300 microliters of HT1, 25 microliters of 20 picomolar PhiX, and 675 microliters of the DAL pool.Add the entire volume of the load tube to the sample well of the sequencer reagent cartridge and load the cartridge in to the sequencer. Start by selecting the positive control sample and ensure that all expected fusions and oncogenic isoforms have been detected and are listed in the strong evidence tab. For each sample, inspect the average unique start sites per GSP2 control value, then visualize the supporting reads for each potential fusion by clicking the Visualize link which takes the user to a web-based JBrowse view of pileups of individual fusion supporting reads.Confirm that the reads are mostly free of mismatch, but more than 30 bases of the reads align with the fusion partner, and that sequences adjacent to the breakpoint between the genes and primer binding sites are free of insertions or deletions. It is critical to ensure that every call fusion is generally free of misalignment and that a significant portion of the reads align to the fusion partner. This protocol has been used to investigate gene fusion status in a lung adenocarcinoma sample.The summary shows strong evidence fusions and the Read Statistics page shows metrics of the sample. This sample exhibits good RNA quality so negative results would be reported if no fusions were found. A legitimate fusion call has a high number of supporting reads, a high percent of reads from the primer supporting the fusion, and a high number of start sites.Visualization of the reads demonstrates good alignment to large regions of the fusion partner. Conversely, an artifactual fusion call has lower supporting metrics and a high error rate when mapping to the partner. Artifactual fusion calls made by the analysis algorithm are common.It is critical to manually inspect every call to ensure that it represents a real gene fusion in the patient sample.

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Research

JoVE Journal

Cancer Research

Next Generation Sequencing for the Detection of Actionable Mutations in Solid and Liquid Tumors

As our understanding of the driver mutations necessary for initiation and progression of cancers improves, we gain critical information on how specific molecular profiles of a tumor may predict responsiveness to therapeutic agents or provide knowledge about prognosis. At our institution a tumor genotyping program was established as part of routine clinical care, screening both hematologic and solid tumors for a wide spectrum of mutations using two next-generation sequencing (NGS) panels: a custom, 33 gene hematological malignancies panel for use with peripheral blood and bone marrow, and a commercially produced solid tumor panel for use with formalin-fixed paraffin-embedded tissue that targets 47 genes commonly mutated in cancer. Our workflow includes a pathologist review of the biopsy to ensure there is adequate amount of tumor for the assay followed by customized DNA extraction is performed on the specimen. Quality control of the specimen includes steps for quantity, quality and integrity and only after the extracted DNA passes these metrics an amplicon library is generated and sequenced. The resulting data is analyzed through an in-house bioinformatics pipeline and the variants are reviewed and interpreted for pathogenicity. Here we provide a snapshot of the utility of each panel using two clinical cases to provide insight into how a well-designed NGS workflow can contribute to optimizing clinical outcomes.

This manuscript describes clinical protocols for two next-generation sequencing panels. One panel interrogates hematologic malignancies while the other panel targets genes commonly mutated in solid tumors. Molecular classification of driver mutations in human malignancies offers valuable prognostic and predictive information.

As our understanding of the driver mutations necessary for initiation and progression of cancers improves, we gain critical information on how specific ...

Detection of Rare Mutations in CtDNA Using Next Generation Sequencing

The analysis of circulating tumor DNA (ctDNA) using next-generation sequencing (NGS) has become a valuable tool for the development of clinical oncology. However, the application of this method is challenging due to its low sensitivity in analyzing the trace amount of ctDNA in the blood. Furthermore, the method may generate false positive and negative results from this sequencing and subsequent analysis. To improve the feasibility and reliability of ctDNA detection in the clinic, here we present a technique which enriches rare mutations for sequencing, Enrich Rare Mutation Sequencing (ER-Seq). ER-Seq can distinguish a single mutation out of 1 x 107 wild-type nucleotides, which makes it a promising tool to detect extremely low frequency genetic alterations and thus will be very useful in studying disease heterogenicity. By virtue of the unique sequencing adapter&#39;s ligation, this method enables an efficient recovery of ctDNA molecules, while at the same time correcting for errors bidirectionally (sense and antisense). Our selection of 1021 kb probes enriches the measurement of target regions that cover over 95% of the tumor-related driver mutations in 12 tumors. This cost-effective and universal method enables a uniquely successful accumulation of genetic data. After efficiently filtering out background error, ER-seq can precisely detect rare mutations. Using a case study, we present a detailed protocol demonstrating probe design, library construction, and target DNA capture methodologies, while also including the data analysis workflow. The process to carry out this method typically takes 1-2 days.

This manuscript describes a technique for detecting mutations of low frequency in ctDNA, ER-Seq. This method is differentiated by its unique use of two-directional error correction, a special background filter, and efficient molecular acquirement.

The analysis of circulating tumor DNA (ctDNA) using next-generation sequencing (NGS) has become a valuable tool for the development of clinical oncology. ...

Looking for Driver Pathways of Acquired Resistance to Targeted Therapy: Drug Resistant Subclone Generation and Sensitivity Restoring by Gene Knock-down

The past two decades have seen a shift from cytotoxic drugs to targeted therapy in medical oncology. Although targeted therapeutic agents have shown more impressive clinical efficacy and minimized adverse effects than traditional treatments, drug resistance has become the main limitation to their benefits. Several preclinical in vitro/in vivo models of acquired resistance to targeted agents in clinical practice have been developed mainly by using two strategies: i) genetic manipulation for modeling genotypes of acquired resistance, and ii) in vitro/in vivo selection of resistant models. In the present work, we propose a unifying framework, for investigating the underlying mechanisms responsible for acquired resistance to targeted therapeutic agents, starting from the generation of drug-resistant cellular subclones to the description of silencing procedures used for restoring the sensitivity to the inhibitor. This simple time- and cost-effective approach is widely applicable, and could be easily extended to investigate resistance mechanisms to other targeted therapeutic drugs in different tumor histotypes.

This is a time- and cost-effective in vitro protocol investigating the mechanisms of acquired resistance to targeted therapeutic agents, which is a highly unmet medical need in cancer management.

The past two decades have seen a shift from cytotoxic drugs to targeted therapy in medical oncology. Although targeted therapeutic agents have shown more ...

Using CRISPR/Cas9 Gene Editing to Investigate the Oncogenic Activity of Mutant Calreticulin in Cytokine Dependent Hematopoietic Cells

Clustered regularly interspaced short palindromic repeats (CRISPR) is an adaptive immunity system in prokaryotes that has been repurposed by scientists to generate RNA-guided nucleases, such as CRISPR-associated (Cas) 9 for site-specific eukaryotic genome editing. Genome engineering by Cas9 is used to efficiently, easily and robustly modify endogenous genes in many biomedically-relevant mammalian cell lines and organisms. Here we show an example of how to utilize the CRISPR/Cas9 methodology to understand the biological function of specific genetic mutations. We model calreticulin (CALR) mutations in murine interleukin-3 (mIL-3) dependent pro-B (Ba/F3) cells by delivery of single guide RNAs (sgRNAs) targeting the endogenous Calr locus in the specific region where insertion and/or deletion (indel) CALR mutations occur in patients with myeloproliferative neoplasms (MPN), a type of blood cancer. The sgRNAs create double strand breaks (DSBs) in the targeted region that are repaired by non-homologous end joining (NHEJ) to give indels of various sizes. We then employ the standard Ba/F3 cellular transformation assay to understand the effect of physiological level expression of Calr mutations on hematopoietic cellular transformation. This approach can be applied to other genes to study their biological function in various mammalian cell lines.

Targeted gene editing using CRISPR/Cas9 has greatly facilitated the understanding of the biological functions of genes. Here, we utilize the CRISPR/Cas9 methodology to model calreticulin mutations in cytokine-dependent hematopoietic cells in order to study their oncogenic activity.

Clustered regularly interspaced short palindromic repeats (CRISPR) is an adaptive immunity system in prokaryotes that has been repurposed by scientists to ...

Digital Polymerase Chain Reaction Assay for the Genetic Variation in a Sporadic Familial Adenomatous Polyposis Patient Using the Chip-in-a-tube Format

The quantitative analysis of human genetic variation is crucial for understanding the molecular characteristics of serious medical conditions, such as tumors. Because digital polymerase chain reactions (PCR) enable the precise quantification of DNA copy number variants, they are becoming an essential tool for detecting rare genetic variations, such as drug-resistant mutations. It is expected that molecular diagnoses using digital PCR (dPCR) will be available in clinical practice in the near future; thus, how to efficiently conduct dPCR with human genetic material is a hot topic. Here, we introduce a method to detect Adenomatous polyposis coli (APC) somatic mosaicism using dPCR with the chip-in-a-tube format, which allows eight dPCR reactions to be simultaneously conducted. Care should be taken when filling and sealing the reaction mixture on the chips. This article demonstrates how to avoid the over- and underestimation of positive partitions. Furthermore, we present a simple procedure for collecting the dPCR product from the partitions on the chips, which can then be used to confirm the specific amplification. We hope that this methods report will help promote the dPCR with the chip-in-a-tube method in genetic research.

Digital polymerase chain reaction (PCR) is a useful tool for the high-sensitivity detection of single nucleotide variants and DNA copy number variants. Here, we demonstrate key considerations for measuring rare variants in the human genome using digital PCR with the chip-in-a-tube format.

The quantitative analysis of human genetic variation is crucial for understanding the molecular characteristics of serious medical conditions, such as ...

Droplet Digital TRAP (ddTRAP): Adaptation of the Telomere Repeat Amplification Protocol to Droplet Digital Polymerase Chain Reaction

The telomere repeat amplification protocol (TRAP) is the most widely used assay to detect telomerase activity within a given a sample. The polymerase chain reaction (PCR)-based method allows for robust measurements of enzyme activity from most cell lysates. The gel-based TRAP with fluorescently labeled primers limits sample throughput, and the ability to detect differences in samples is restricted to two fold or greater changes in enzyme activity. The droplet digital TRAP, ddTRAP, is a highly sensitive approach that has been modified from the traditional TRAP assay, enabling the user to perform a robust analysis on 96 samples per run and obtain absolute quantification of the DNA (telomerase extension products) input within each PCR. Therefore, the newly developed ddTRAP assay overcomes the limitations of the traditional gel-based TRAP assay and provides a more efficient, accurate, and quantitative approach to measuring telomerase activity within laboratory and clinical settings.

Droplet Digital TRAP ddTRAP: Adaptation of the Telomere Repeat Amplification Protocol to Droplet Digital Polymerase Chain Reaction

We successfully converted the standard telomere repeat amplification protocol (TRAP) assay to be employed in droplet digital polymerase chain reactions. This new assay, called ddTRAP, is more sensitive and quantitative, allowing for better detection and statistical analysis of telomerase activity within various human cells.

The telomere repeat amplification protocol (TRAP) is the most widely used assay to detect telomerase activity within a given a sample. The polymerase ...

Mapping the Structure-Function Relationships of Disordered Oncogenic Transcription Factors Using Transcriptomic Analysis

Many cancers are characterized by chromosomal translocations which result in the expression of oncogenic fusion transcription factors. Typically, these proteins contain an intrinsically disordered domain (IDD) fused with the DNA-binding domain (DBD) of another protein and orchestrate widespread transcriptional changes to promote malignancy. These fusions are often the sole recurring genomic aberration in the cancers they cause, making them attractive therapeutic targets. However, targeting oncogenic transcription factors requires a better understanding of the mechanistic role that low-complexity, IDDs play in their function. The N-terminal domain of EWSR1 is an IDD involved in a variety of oncogenic fusion transcription factors, including EWS/FLI, EWS/ATF, and EWS/WT1. Here, we use RNA-sequencing to investigate the structural features of the EWS domain important for transcriptional function of EWS/FLI in Ewing sarcoma. First shRNA-mediated depletion of the endogenous fusion from Ewing sarcoma cells paired with ectopic expression of a variety of EWS-mutant constructs is performed. Then RNA-sequencing is used to analyze the transcriptomes of cells expressing these constructs to characterize the functional deficits associated with mutations in the EWS domain. By integrating the transcriptomic analyses with previously published information about EWS/FLI DNA binding motifs, and genomic localization, as well as functional assays for transforming ability, we were able to identify structural features of EWS/FLI important for oncogenesis and define a novel set of EWS/FLI target genes critical for Ewing sarcoma. This paper demonstrates the use of RNA-sequencing as a method to map the structure-function relationship of the intrinsically disordered domain of oncogenic transcription factors.

Intrinsically disordered domains are important for oncogenic fusion transcription factor function. To therapeutically target these proteins, a more detailed understanding of the regulatory mechanisms employed by these domains is required. Here, we use transcriptomics to map important structural features of the intrinsically disordered EWS domain in Ewing sarcoma.

Many cancers are characterized by chromosomal translocations which result in the expression of oncogenic fusion transcription factors. Typically, these ...

In Vitro Evaluation of Oncogenic Transformation in Human Mammary Epithelial Cells

Tumorigenesis is a multi-step process in which cells acquire capabilities&#160;that allow their growth, survival, and dissemination under hostile conditions. Different tests seek to identify and quantify these hallmarks of cancerous cells; however, they often focus on a single aspect of cellular transformation and, in fact, multiple tests are required for their proper characterization. The purpose of this work is to provide researchers with a set of tools to assess cellular transformation in vitro from a broad perspective, thereby making it possible to draw sound conclusions.
A sustained proliferative signaling activation is the major feature of tumoral tissues and can be easily monitored under in vitro conditions by calculating the number of population doublings achieved over time. Besides, the growth of cells in 3D cultures allows their interaction with surrounding cells, resembling what occurs in vivo. This enables the evaluation of cellular aggregation and, together with immunofluorescent labeling of distinctive cellular markers, to obtain information on another relevant feature of tumoral transformation: the loss of proper organization. Another remarkable characteristic of transformed cells is their capacity to grow without attachment to other cells and to the extracellular matrix, which can be evaluated with the anchorage assay.
Detailed experimental procedures to evaluate cell growth rate, to perform immunofluorescent labeling of cell lineage markers in 3D cultures, and to test anchorage-independent cell growth in soft agar are provided. These methodologies are optimized for Breast Primary Epithelial Cells (BPEC) due to its relevance in breast cancer; however, procedures can be applied to other cell types after some adjustments.

This protocol provides experimental in vitro tools to evaluate the transformation of human mammary cells. Detailed steps to follow-up cell proliferation rate, anchorage-independent growth capacity, and distribution of cell lineages in 3D cultures with basement membrane matrix are described.

Tumorigenesis is a multi-step process in which cells acquire capabilities&#160;that allow their growth, survival, and dissemination under hostile ...

Spatial Profiling of Protein and RNA Expression in Tissue: An Approach to Fine-Tune Virtual Microdissection

Multiplexing enables the assessment of several markers on the same tissue while providing spatial context. Spatial Omics technologies allow both protein and RNA multiplexing by leveraging photo-cleavable oligo-tagged antibodies and probes, respectively. Oligos are cleaved and quantified from specific regions across the tissue to elucidate the underlying biology. Here, the study demonstrates that automated custom antibody visualization protocols can be utilized to guide ROI selection in conjunction with spatial proteomics assays. This specific method did not show acceptable performance with spatial transcriptomics assays. The protocol describes the development of a 3-plex immunofluorescent (IF) assay for marker visualization on an automated platform, using tyramide signal amplification (TSA) to amplify the fluorescent signal from a given protein target and increase the antibody pool to choose from. The visualization protocol was automated using a thoroughly validated 3-plex assay to ensure quality and reproducibility. In addition, the exchange of DAPI for SYTO dyes was evaluated to allow imaging of TSA-based IF assays on the spatial profiling platform. Additionally, we tested the ability of selecting small ROIs using the spatial transcriptomics assay to allow the investigation of highly-specific areas of interest (e.g., areas enriched for a given cell type). ROIs of 50 &#181;m and 300 &#181;m diameter were collected, which corresponds to approximately 15 cells and 100 cells, respectively. Samples were made into libraries and sequenced to investigate the capability to detect signals from small ROIs and profile-specific regions of the tissue. We determined that spatial proteomics technologies highly benefit from automated, standardized protocols to guide ROI selection. While this automated visualization protocol was not compatible with spatial transcriptomics assays, we were able to test and confirm that specific cell populations can successfully be detected even in small ROIs with the standard manual visualization protocol.

Here, we describe a protocol for fine-tuning regions of interest (ROIs) for Spatial Omics technologies to better characterize the tumor microenvironment and identify specific cell populations. For proteomics assays, automated customized protocols can guide ROI selection, while transcriptomics assays can be fine-tuned utilizing ROIs as small as 50 &#181;m.

Multiplexing enables the assessment of several markers on the same tissue while providing spatial context. Spatial Omics technologies allow both protein ...

Transmitochondrial Cybrid Generation From Suspension-Growing Cancer Cells

Transmitochondrial Cybrid Generation Using Cancer Cell Lines

In recent years, the number of studies dedicated to ascertaining the connection between mitochondria and cancer has significantly risen. However, more efforts are still needed to fully understand the link involving alterations in mitochondria and tumorigenesis, as well as to identify tumor-associated mitochondrial phenotypes. For instance, to evaluate the contribution of mitochondria in tumorigenesis and metastasis processes, it is essential to understand the influence of mitochondria from tumor cells in different nuclear environments. For this purpose, one possible approach consists of transferring mitochondria into a different nuclear background to obtain the so-called cybrid cells. In the traditional cybridization techniques, a cell line lacking mtDNA (&#961;0, nuclear donor cell) is repopulated with mitochondria derived from either enucleated cells or platelets. However, the enucleation process requires good cell adhesion to the culture plate, a feature that is partially or completely lost in many cases in invasive cells. In addition, another difficulty found in the traditional methods is achieving complete removal of the endogenous mtDNA from the mitochondrial-recipient cell line to obtain pure nuclear and mitochondrial DNA backgrounds, avoiding the presence of two different mtDNA species in the generated cybrid. In this work, we present a mitochondrial exchange protocol applied to suspension-growing cancer cells based on the repopulation of rhodamine 6G-pretreated cells with isolated mitochondria. This methodology allows us to overcome the limitations of the traditional approaches, and thus can be used as a tool to expand the comprehension of the mitochondrial role in cancer progression and metastasis.

Author Spotlight: Transmitochondrial Cybrid Generation Using Cancer Cell Lines  

This protocol describes a technique for cybrid generation from suspension-growing cancer cells as a tool to study the role of mitochondria in the tumorigenic process.

In recent years, the number of studies dedicated to ascertaining the connection between mitochondria and cancer has significantly risen. However, more ...