Name: using the e1a minigene tool to study mrna splicing changes
Uploaded: 2021-04-22T13:30:00
Description: Watch this Scientific Journal Video about Using the E1A Minigene Tool to Study mRNA Splicing Changes at JoVE.com

We thank Funda&#231;&#227;o de Amparo a Pesquisa do Estado de S&#227;o Paulo (FAPESP, through Grant Tem&#225;tico 2017/03489-1 to JK and fellowship to FLB 2018/05350-3) and the Conselho Nacional de Desenvolvimento Cientifico e Tecnol&#243;gico (CNPq) for funding this research. We would like to thank Dr Adrian Krainer for providing the pMTE1A plasmid and Zerler and colleagues for their work in E1A cloning. We also thank Prof. Dr. Patr&#237;cia Moriel, Prof. Dr. Wanda Pereira Almeida, Prof. Dr. Marcelo Lancellotti and Prof. Dr. Karina Kogo Cogo M&#252;ller to allow us to use their laboratory space and equipment.

1. Plating cells
NOTE: In this described protocol, HEK293 stable cell lines, previously generated for stable inducible expression of Nek4 were used21, however, the same protocol is suitable to many other cell lines, such as HEK29322, HeLa23,24,25,26, U-2 OS27, COS728, SH-SY5...

<ol>
	<li>Ule, J., Blencowe, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alternative+Splicing+Regulatory+Networks:+Functions,+Mechanisms,+and+Evolution.">Alternative Splicing Regulatory Networks: Functions, Mechanisms, and Evolution.</a> Molecular Cell. 76 (2), 329-345 (2019).</li><li>Pan, Q., Shai, O., Lee, L. J., Frey, B. J., Blencowe, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deep+surveying+of+alternative+splicing+complexity+in+the+human+transcriptome+by+high-throughput+sequencing.">Deep surveying of alternative splicing complexity in the human transcriptome by high-throughput sequencing.</a> Nature Genetics. 40 (12), 1413-1415 (2008).</li><li>Nilsen, T. W., Graveley, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expansion+of+the+eukaryotic+proteome+by+alternative+splicing.">Expansion of the eukaryotic proteome by alternative splicing.</a> Nature. 463 (7280), 457-463 (2010).</li><li>Stamm, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Signals+and+their+transduction+pathways+regulating+alternative+splicing:+a+new+dimension+of+the+human+genome.">Signals and their transduction pathways regulating alternative splicing: a new dimension of the human genome.</a> Human Molecular Genetics. 11 (20), 2409-2416 (2002).</li><li>Kornblihtt, A. 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=Alternative+splicing:+a+pivotal+step+between+eukaryotic+transcription+and+translation.">Alternative splicing: a pivotal step between eukaryotic transcription and translation.</a> Nature Reviews Molecular Cell Biology. 14 (3), 153-165 (2013).</li><li>Zhong, X. -. Y., Ding, J. -. H., Adams, J. A., Ghosh, G., Fu, X. -. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+SR+protein+phosphorylation+and+alternative+splicing+by+modulating+kinetic+interactions+of+SRPK1+with+molecular+chaperones.">Regulation of SR protein phosphorylation and alternative splicing by modulating kinetic interactions of SRPK1 with molecular chaperones.</a> Genes &amp; Development. 23 (4), 482-495 (2009).</li><li>Misteli, T., C&#225;ceres, J. F., Clement, J. Q., Krainer, A. R., Wilkinson, M. F., Spector, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serine+Phosphorylation+of+SR+Proteins+Is+Required+for+Their+Recruitment+to+Sites+of+Transcription+In+Vivo.">Serine Phosphorylation of SR Proteins Is Required for Their Recruitment to Sites of Transcription In Vivo.</a> Journal of Cell Biology. 143 (2), 297-307 (1998).</li><li>Kanopka, 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=Regulation+of+adenovirus+alternative+RNA+splicing+by+dephosphorylation+of+SR+proteins.">Regulation of adenovirus alternative RNA splicing by dephosphorylation of SR proteins.</a> Nature. 393 (6681), 185-187 (1998).</li><li>Anufrieva, K. 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=Therapy-induced+stress+response+is+associated+with+downregulation+of+pre-mRNA+splicing+in+cancer+cells.">Therapy-induced stress response is associated with downregulation of pre-mRNA splicing in cancer cells.</a> Genome Medicine. 10 (1), 49 (2018).</li><li>Shultz, J. 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=SRSF1+Regulates+the+Alternative+Splicing+of+Caspase+9+Via+A+Novel+Intronic+Splicing+Enhancer+Affecting+the+Chemotherapeutic+Sensitivity+of+Non-Small+Cell+Lung+Cancer+Cells.">SRSF1 Regulates the Alternative Splicing of Caspase 9 Via A Novel Intronic Splicing Enhancer Affecting the Chemotherapeutic Sensitivity of Non-Small Cell Lung Cancer Cells.</a> Molecular Cancer Research. 9 (7), 889-900 (2011).</li><li>Gabriel, 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=Role+of+the+splicing+factor+SRSF4+in+cisplatin-induced+modifications+of+pre-mRNA+splicing+and+apoptosis.">Role of the splicing factor SRSF4 in cisplatin-induced modifications of pre-mRNA splicing and apoptosis.</a> BMC Cancer. 15, (2015).</li><li>Lee, S. C. -. W., Abdel-Wahab, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Therapeutic+targeting+of+splicing+in+cancer.">Therapeutic targeting of splicing in cancer.</a> Nature Medicine. 22 (9), 976-986 (2016).</li><li>Cooper, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+minigene+systems+to+dissect+alternative+splicing+elements.">Use of minigene systems to dissect alternative splicing elements.</a> Methods. 37 (4), 331-340 (2005).</li><li>Stoss, O., Stoilov, P., Hartmann, A. M., Nayler, O., Stamm, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+in+vivo+minigene+approach+to+analyze+tissue-specific+splicing.">The in vivo minigene approach to analyze tissue-specific splicing.</a> Brain Research Protocols. 4 (3), 383-394 (1999).</li><li>Zerler, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adenovirus+E1A+coding+sequences+that+enable+ras+and+pmt+oncogenes+to+transform+cultured+primary+cells.">Adenovirus E1A coding sequences that enable ras and pmt oncogenes to transform cultured primary cells.</a> Molecular and Cellular Biology. 6 (3), 887-899 (1986).</li><li>Gattoni, R., Schmitt, P., Stevenin, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+splicing+of+adenovirus+E1A+transcripts:+characterization+of+novel+reactions+and+of+multiple+branch+points+abnormally+far+from+the+3'+splice+site.">In vitro splicing of adenovirus E1A transcripts: characterization of novel reactions and of multiple branch points abnormally far from the 3' splice site.</a> Nucleic Acids Research. 16 (6), 2389-2409 (1988).</li><li>Stephens, C., Harlow, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+splicing+yields+novel+adenovirus+5+E1A+mRNAs+that+encode+30+kd+and+35+kd+proteins.">Differential splicing yields novel adenovirus 5 E1A mRNAs that encode 30 kd and 35 kd proteins.</a> The EMBO journal. 6 (7), 2027-2035 (1987).</li><li>Ulfendahl, P. 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=A+novel+adenovirus-2+E1A+mRNA+encoding+a+protein+with+transcription+activation+properties.">A novel adenovirus-2 E1A mRNA encoding a protein with transcription activation properties.</a> The EMBO journal. 6 (7), 2037-2044 (1987).</li><li>Berk, A. J., Sharp, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+the+adenovirus+2+early+mRNAs.">Structure of the adenovirus 2 early mRNAs.</a> Cell. 14 (3), 695-711 (1978).</li><li>Svensson, C., Pettersson, U., Akusj&#228;rvi, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Splicing+of+adenovirus+2+early+region+1A+mRNAs+is+non-sequential.">Splicing of adenovirus 2 early region 1A mRNAs is non-sequential.</a> Journal of Molecular Biology. 165 (3), 475-495 (1983).</li><li>Basei, F. L., Meirelles, G. V., Righetto, G. L., dos Santos Migueleti, D. L., Smetana, J. H. C., Kobarg, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+interaction+partners+for+Nek4.1+and+Nek4.2+isoforms:+from+the+DNA+damage+response+to+RNA+splicing.">New interaction partners for Nek4.1 and Nek4.2 isoforms: from the DNA damage response to RNA splicing.</a> Proteome Science. 13 (1), 11 (2015).</li><li>Zhou, 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=The+Akt-SRPK-SR+Axis+Constitutes+a+Major+Pathway+in+Transducing+EGF+Signaling+to+Regulate+Alternative+Splicing+in+the+Nucleus.">The Akt-SRPK-SR Axis Constitutes a Major Pathway in Transducing EGF Signaling to Regulate Alternative Splicing in the Nucleus.</a> Molecular Cell. 47 (3), 422-433 (2012).</li><li>Caceres, J., Stamm, S., Helfman, D., Krainer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+alternative+splicing+in+vivo+by+overexpression+of+antagonistic+splicing+factors.">Regulation of alternative splicing in vivo by overexpression of antagonistic splicing factors.</a> Science. 265 (5179), 1706-1709 (1994).</li><li>Zhong, X. -. Y., Ding, J. -. H., Adams, J. A., Ghosh, G., Fu, X. -. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+SR+protein+phosphorylation+and+alternative+splicing+by+modulating+kinetic+interactions+of+SRPK1+with+molecular+chaperones.">Regulation of SR protein phosphorylation and alternative splicing by modulating kinetic interactions of SRPK1 with molecular chaperones.</a> Genes &amp; Development. 23 (4), 482-495 (2009).</li><li>Naro, 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=The+centrosomal+kinase+NEK2+is+a+novel+splicing+factor+kinase+involved+in+cell+survival.">The centrosomal kinase NEK2 is a novel splicing factor kinase involved in cell survival.</a> Nucleic Acids Research. 42 (5), 3218-3227 (2014).</li><li>Lu, C. -. C., Chen, T. -. H., Wu, J. -. R., Chen, H. -. H., Yu, H. -. Y., Tarn, W. -. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phylogenetic+and+Molecular+Characterization+of+the+Splicing+Factor+RBM4.">Phylogenetic and Molecular Characterization of the Splicing Factor RBM4.</a> PLoS ONE. 8 (3), 59092 (2013).</li><li>Jarn&#230;ss, 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=Splicing+Factor+Arginine/Serine-rich+17A+(SFRS17A)+Is+an+A-kinase+Anchoring+Protein+That+Targets+Protein+Kinase+A+to+Splicing+Factor+Compartments.">Splicing Factor Arginine/Serine-rich 17A (SFRS17A) Is an A-kinase Anchoring Protein That Targets Protein Kinase A to Splicing Factor Compartments.</a> Journal of Biological Chemistry. 284 (50), 35154-35164 (2009).</li><li>Bressan, G. 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=Functional+association+of+human+Ki-1/57+with+pre-mRNA+splicing+events.">Functional association of human Ki-1/57 with pre-mRNA splicing events.</a> FEBS Journal. 276 (14), 3770-3783 (2009).</li><li>Vivarelli, 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=Paraquat+Modulates+Alternative+Pre-mRNA+Splicing+by+Modifying+the+Intracellular+Distribution+of+SRPK2.">Paraquat Modulates Alternative Pre-mRNA Splicing by Modifying the Intracellular Distribution of SRPK2.</a> PLoS ONE. 8 (4), 61980 (2013).</li><li>Russell, W. C., Graham, F. L., Smiley, J., Nairn, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characteristics+of+a+Human+Cell+Line+Transformed+by+DNA+from+Human+Adenovirus+Type+5.">Characteristics of a Human Cell Line Transformed by DNA from Human Adenovirus Type 5.</a> Journal of General Virology. 36 (1), 59-72 (1977).</li><li>Aranda, P. S., LaJoie, D. M., Jorcyk, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bleach+gel:+A+simple+agarose+gel+for+analyzing+RNA+quality.">Bleach gel: A simple agarose gel for analyzing RNA quality.</a> Electrophoresis. 33 (2), 366-369 (2012).</li><li>Schindelin, 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=Fiji:+an+open-source+platform+for+biological-image+analysis.">Fiji: an open-source platform for biological-image analysis.</a> Nature Methods. 9 (7), 676-682 (2012).</li><li>Bai, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+3'+splice+site+choice+in+vivo+by+ASF/SF2+and+hnRNP+A1.">Control of 3' splice site choice in vivo by ASF/SF2 and hnRNP A1.</a> Nucleic Acids Research. 27 (4), 1126-1134 (1999).</li><li>Cote, G. J., Nguyen, N., Lips, C. J. M., Berget, S. M., Gagel, R. F. <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+an+in+vitro+RNA+processing+system+for+CT/CGRP+precursor+mRNA.">Validation of an in vitro RNA processing system for CT/CGRP precursor mRNA.</a> Nucleic Acids Research. 19 (13), 3601-3606 (1991).</li></ol>

Minigenes are important tools to determine the effects in global alternative splicing in vivo. The adenoviral minigene E1A has been used successfully for decades to evaluate the role of proteins by increasing the amount of these in the cell13,14. Here, we propose the minigene E1A use for evaluating alternative splicing after chemotherapeutic exposure. A stable cell line expressing Nek4 isoform 1 was used, avoiding the artifacts of overexpression caused by transie...

Splicing is among the most important steps in eukaryotic mRNA processing that occurs simultaneously to 5&#180;mRNA capping and 3&#180;mRNA polyadenylation, comprising of intron removal followed by exon junction. The recognition of the splicing sites (SS) by the spliceosome, a ribonucleoprotein complex containing small ribonucleoproteins (snRNP U1, U2, U4 and U6), small RNAs (snRNAs) and several regulatory proteins1 is necessary for splicing.
Besides intron removal (constitutive splicing), in eukaryotes, introns can be retained and exons can be excluded, configuring the process called mRNA alternative splicing (AS). The alternative pre-mRNA splicing expands the coding capacity of eukaryotic genomes allowing the production of a large and diverse number of proteins from a relatively small number of genes. It is estimated that 95-100% of human mRNAs that contain more than one exon can undergo alternative splicing2,3. This is fundamental for biological processes like neuronal development, apoptosis activation and cellular stress response4, providing the organism alternatives to regulate cell functioning using the same repertoire of genes.
The machinery necessary for alternative splicing is the same used for constitutive splicing and the usage of the SS is the main determinant for alternative splicing occurrence. Constitutive splicing is related to the use of strong splicing sites, which are usually more similar to consensus motifs for spliceosome recognition5.
Alternative exons are typically recognized less efficiently than constitutive exons once its cis-regulatory elements, the sequences in 5&#180;SS and 3&#180;SS flanking these exons, show an inferior binding capacity to the spliceosome. mRNA also contains regions named enhancers or silencers located in exons (exonic splicing enhancers (ESEs) and exonic splicing silencers (ESSs)) and introns (intronic splicing enhancers (ISEs) and intronic splicing silencers (ISSs)) that enhance or repress exon usage, respectively5. These sequences are recognized by trans-regulatory elements, or splicing factors (SF). SFs are represented mainly by two families of proteins, the serine/arginine rich splicing factors (SRSFs) which bind to ESEs and the family of heterogeneous nuclear ribonucleoproteins (hnRNPs) which bind to ESSs sequences5.
Alternative splicing can be modulated by phosphorylation/ dephosphorylation of trans- factors modifying the interactions partners and cellular localization of splicing factors6,7,8. Identifying new regulators of splicing factors can provide new tools to regulate splicing and, consequently, some cancer treatments.
Anufrieva et al.9, in a mRNA microarray gene expression profile, observed consistent changes in levels of spliceosomal components in 101 cell lines and after different stress conditions (platinum-based drugs, gamma irradiation, topoisomerase inhibitors, tyrosine kinase inhibitors and taxanes). The relationship among splicing pattern and chemotherapy efficacy has already been demonstrated in lung cancer cells, which are chemotherapy resistant, showing changes in caspase-9 variants rate10. HEK293 cells treated with chemotherapeutics panel show changes in splicing with an increase in pro-apoptotic variants. Gabriel et al.11 observed changes in at least 700 events of splicing after cisplatin treatment in different cell lines, pointing out that splicing pathways are cisplatin-affected. Splicing modulators have already demonstrated anti-tumoral activity, showing that splicing is important to tumoral development and, mainly, chemotherapy response12. Hence, characterizing new proteins that regulate splicing after cellular stressors agents, like chemotherapeutics, is very important to discover new strategies of treatment.
The clues of alternative splicing regulation from interactome studies, particularly important to characterize functions of new or uncharacterized proteins, can demand a more general and simple approach to verify the real role of the protein in AS. Minigenes are important tools for analysis of the general role of a protein affecting splicing regulation. They contain segments from a gene of interest containing alternatively spliced and flanking genomic regions13. Using a minigene tool allows the analysis of splicing in vivo with several advantages such as the length of the minigene which is minor and therefore is not a limitation to the amplification reaction; the same minigene can be evaluated in different cell lines; all cellular components, mainly their regulating post-translational modification (phosphorylation and changes in cell compartments) are present and can be addressed13,14. Moreover, changes in alternative splicing pattern can be observed after cellular stress and, the use of a minigene system, allow to identify the pathway being modulated by different stimuli.
There are several minigene systems already described which are specific for different kinds of splicing events13,14, however, as a preliminary assay, the minigene E1A15 is a very well established alternative splicing reporter system for the study of 5&#180;SS selection in vivo. From only one gene, E1A, five mRNAs are produced by alternative splicing based on selection of three different 5&#8242; splice sites and of one major or one minor 3&#8242; splice site16,17,18. The expression of E1A variants changes according to the period of Adenoviral infection19,20.
We have shown previously that both Nek4 isoforms interact with splicing factors such as SRSF1 and hnRNPA1 and while isoform 2 changes minigene E1A alternative splicing, isoform 1 has no effect in that21. Because isoform 1 is the most abundant isoform and changes chemotherapy resistance and DNA damage response, we evaluate if it could change minigene E1A alternative splicing in a stress condition.
Minigene assay is a simple, low-cost and rapid method, since it only needs RNA extraction, cDNA synthesis, amplification and agarose gel analyses, and can be a useful tool to evaluate since a possible effect on alternative splicing by a protein of interests until the effect of different treatments on cellular alternative splicing pattern.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>100 pb DNA Ladder</td>
			<td>Invitrogen</td>
			<td>15628-050</td>
			<td></td>
		</tr>
		<tr>
			<td>6 wells plate</td>
			<td>Sarstedt</td>
			<td>833920</td>
			<td></td>
		</tr>
		<tr>
			<td>Agarose</td>
			<td>Sigma</td>
			<td>A9539-250G</td>
			<td></td>
		</tr>
		<tr>
			<td>Cisplatin</td>
			<td>Sigma</td>
			<td>P4394</td>
			<td></td>
		</tr>
		<tr>
			<td>DEPC water</td>
			<td>ThermoFisher</td>
			<td>AM9920</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>ThermoFisher</td>
			<td>11965118</td>
			<td></td>
		</tr>
		<tr>
			<td>dNTP mix</td>
			<td>ThermoFisher</td>
			<td>10297-018</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum - FBS</td>
			<td>ThermoFisher</td>
			<td>12657029</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluorescent Microscope</td>
			<td>Leica</td>
			<td>DMIL LED FLUO</td>
			<td></td>
		</tr>
		<tr>
			<td>Gel imaging acquisition system - ChemiDoc Gel Imagin System</td>
			<td>Bio-Rad</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>GFP - pEGFPC3</td>
			<td>Clontech</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>HEK293 stable cells - HEK293 Flp-In</td>
			<td></td>
			<td></td>
			<td>Generated from Flp-In&#8482; T-REx&#8482; 293 - Invitrogen and described in ref 21</td>
		</tr>
		<tr>
			<td>Hygromycin B</td>
			<td>ThermoFisher</td>
			<td>10687010</td>
			<td>Used for Flp-In cells maintenemant</td>
		</tr>
		<tr>
			<td>Image processing and analysis software - FIJI software</td>
			<td></td>
			<td></td>
			<td>ref. 32</td>
		</tr>
		<tr>
			<td>Lipid- based transfection reagent - jetOPTIMUS Polyplus Reagent</td>
			<td>Polyplus</td>
			<td>117-07</td>
			<td></td>
		</tr>
		<tr>
			<td>Oligo DT</td>
			<td>ThermoFisher</td>
			<td>18418020</td>
			<td></td>
		</tr>
		<tr>
			<td>Paclitxel</td>
			<td>Invitrogen</td>
			<td>P3456</td>
			<td></td>
		</tr>
		<tr>
			<td>Plate Reader/ UV absorbance</td>
			<td>Biotech</td>
			<td></td>
			<td>Epoch Biotek/ Take3 adapter</td>
		</tr>
		<tr>
			<td>pMTE1A plasmid</td>
			<td></td>
			<td></td>
			<td>Provided by Dr. Adrian Krainer</td>
		</tr>
		<tr>
			<td>pMTE1A F</td>
			<td>Invitrogen</td>
			<td>&#160;5&#8217; -ATTATCTGCCACGGAGGTGT-3</td>
			<td></td>
		</tr>
		<tr>
			<td>pMTE1A R</td>
			<td>Invitrogen</td>
			<td>5&#8217; -GGATAGCAGGCGCCATTTTA-3&#8217;</td>
			<td></td>
		</tr>
		<tr>
			<td>Refrigerated centrifuge</td>
			<td>Eppendorf</td>
			<td>F5810R</td>
			<td></td>
		</tr>
		<tr>
			<td>Reverse Transcriptase - M-MLV</td>
			<td>ThermoFisher</td>
			<td>28025013</td>
			<td></td>
		</tr>
		<tr>
			<td>Reverse transcriptase - Superscript IV</td>
			<td>ThermoFisher</td>
			<td>18090050</td>
			<td></td>
		</tr>
		<tr>
			<td>Ribunuclease inhibitor RNAse OUT</td>
			<td>ThermoFisher</td>
			<td>10777-019</td>
			<td></td>
		</tr>
		<tr>
			<td>RNA extraction phenol-chloroform based reagent - Trizol</td>
			<td>ThermoFisher</td>
			<td>15596018</td>
			<td></td>
		</tr>
		<tr>
			<td>SybrSafe DNA gel stain</td>
			<td>ThermoFisher</td>
			<td>S33102</td>
			<td></td>
		</tr>
		<tr>
			<td>Taq Platinum</td>
			<td>Thermo</td>
			<td>10966026</td>
			<td></td>
		</tr>
		<tr>
			<td>Tetracyclin</td>
			<td>Sigma</td>
			<td>T3383</td>
			<td>Used for Flag empty or Nek4- Flag expression induction</td>
		</tr>
		<tr>
			<td>Thermocycler Bio-Rad</td>
			<td>Bio-Rad</td>
			<td>T100</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin</td>
			<td>Sigma</td>
			<td>T4799</td>
			<td></td>
		</tr>
	</tbody>
</table>

using the e1a minigene tool to study mrna splicing changes

mRNA processing involves multiple simultaneous steps to prepare mRNA for translation, such as 5&#180;capping, poly-A addition and splicing. Besides constitutive splicing, alternative mRNA splicing allows the expression of multifunctional proteins from one gene. As interactome studies are generally the first analysis for new or unknown proteins, the association of the bait protein with splicing factors is an indication that it can participate in mRNA splicing process, but to determine in what context or what genes are regulated is an empirical process. A good starting point to evaluate this function is using the classical minigene tool. Here we present the adenoviral E1A minigene usage for evaluating the alternative splicing changes after different cellular stress stimuli. We evaluated the splicing of E1A minigene in HEK293 stably overexpressing Nek4 protein after different stressing treatments. The protocol includes E1A minigene transfection, cell treatment, RNA extraction and cDNA synthesis, followed by PCR and gel analysis and quantification of the E1A spliced variants. The use of this simple and well-established method combined with specific treatments is a reliable starting point to shed light on cellular processes or what genes can be regulated by mRNA splicing.

A 5&#180; splice sites&#160;assay using E1A minigene was performed to evaluate changes in splicing profile in cells after chemotherapy exposition. The role of Nek4 - isoform 1 in AS regulation in HEK293 stable cells after paclitaxel or cisplatin treatment was evaluated.
Adenoviral E1A region is responsible for the production of three main mRNAs from one RNA precursor because of the use of different splice donors. They share comm...

Watch this Scientific Journal Video about Using the E1A Minigene Tool to Study mRNA Splicing Changes at JoVE.com

Using the E1A Minigene Tool to Study mRNA Splicing Changes

This protocol presents a rapid and useful tool for evaluating the role of a protein with uncharacterized function in alternative splicing regulation after chemotherapeutic treatment.

mRNA processing involves multiple simultaneous steps to prepare mRNA for translation, such as 5&#180;capping, poly-A addition and splicing. Besides ...

The overall goal of this protocol is to provide detailed guidance to use the minigene E1A2 for evaluating global mRNA splicing changes. This is a quick, inexpensive, and simple tool for assessing the function of the target protein in alternative splicing regulation without the necessity of special regimes or laboratory conditions. Begin by culturing HEK 293 cells with stable expression of the gene of interest.Split the cells using 0.25%trypsin EDTA, then plate 300, 000 cells per well in six-well plates and incubate them for 24 hours at 37 degrees Celsius in 5%carbon dioxide. After 24 hours, check the confluence, and transfect HEK 293 stable cells only when 70 to 80%confluent. Carefully remove the cell culture medium with a pipette, then add two milliliters of complete DMEM medium without antibiotics and put the plate back in the incubator.Prepare a tube with the transfection buffer, then add two micrograms of pMTE1A DNA, vortex, and add two microliters of transfection reagent. Vortex again and incubate for 10 minutes at room temperature. Remove the plates from the incubator and carefully add the transfection mixture drop-wise.Six hours after the transfection, add tetracycline to HEK 293 stable cells for Nek4 expression induction. 24 hours after the transfection, verify cell morphology and transfection efficiency using a fluorescent microscope. Use a pipette to remove the cell culture medium, then add cell culture medium with the chemotherapeutics.Incubate the cells for another 24 hours. To collect RNA, discard the cell culture medium, and add 0.5 to 1 milliliter of RNA extraction reagent directly to the well. If wells are very confluent, use one milliliter of RNA extraction reagent to improve RNA quality.Homogenize the cells with a pipette and transfer them to a 1.5 milliliter centrifuge tube. Proceed immediately to the RNA extraction, or store the samples at minus 80 degrees Celsius. Thaw the samples in a fume hood and incubate for five minutes at room temperature.Add 0.1 to 0.2 milliliters of chloroform and agitate vigorously, then incubate for three minutes at room temperature. Centrifuge for 15 minutes at 12, 000 times G and four degrees Celsius, then collect the upper aqueous phase and transfer it to a new 1.5 milliliter centrifuge tube. Collect around 60%of the total volume, but do not collect the DNA or the organic phase.Add 0.25 to 0.5 milliliters of isopropanol and agitate the sample by inversion four times. Incubate for 10 minutes at room temperature, then centrifuge at 12, 000 times G for 10 minutes at four degrees Celsius and discard the supernatant. Wash the RNA pellet twice with ethanol, and centrifuge at 7, 500 times G for five minutes, then discard the ethanol.Remove excess ethanol by inverting the tube on a paper towel, then leave the tube open inside a fume hood to partially dry the pellet for five to 10 minutes. Re-suspend the RNA pellet in 15 microliters of DEPC-treated water. Quantify total RNA and verify RNA quality by measuring absorbance at 230, 260, and 280 nanometers.To verify total RNA quality, run a 1%agarose gel pretreated with 1.2%of a 2.5%sodium hypochlorite solution for 30 minutes. Perform cDNA synthesis using one to two micrograms of total RNA. Combine RNA, one microliter of oligo d-T, one microliter of DNTP, and nuclease-free water to 12 microliters.Incubate the reaction in the Thermo Cycler for five minutes at 65 degrees Celsius. Remove samples from the Thermo Cycler, and add four microliters of reverse transcriptase buffer, two microliters of DTT, and one microliter of ribonuclease inhibitor. Incubate at 37 degrees Celsius for two minutes.Add one microliter of thermo-stable reverse transcriptase, and incubate at 37 degrees Celsius for 50 minutes. Inactivate the enzyme at 70 degrees Celsius for 15 minutes. Perform PCR as described in the text manuscript, then load 20 to 25 microliters of the PCR product on a 3%agarose gel containing nucleic acid stain, and run at 100 volts for approximately one hour.Photograph the gel, avoiding any band saturation, and quantify the bands using an image processing software. The bands at 631, 493, and 156 base pairs correspond to the 13S, 12S, and 9S isoforms respectively. From the software's File menu, open the image file and convert it to gray scale.Adjust Brightness and Contrast, then remove outlier noise if necessary. Draw a rectangle around the first lane with the rectangle selection tool, and select it through the Analyze, Gels, and Select First Lane command, or by using the keyboard shortcut. Use the mouse to click and hold in the middle of the rectangle on the first lane, and drag it over to the next lane.Go to Analyze, Gels, and Select Next Lane. Repeat this step for all remaining lanes. After all the lanes are highlighted and numbered, go to Analyze, Gels, and Plot Lanes to draw a profile plot of each lane.Use the straight line selection tool to draw a line across the base of each peak, corresponding to each band, leaving out the background noise. After all the peaks from every lane have been closed off, select the wand tool and click inside each peak. Measurements should pop up in the results window for each highlighted peak.Consider only the 13S, 12S, and 9S peaks corresponding to 631, 493, and 156 base pairs bands. Copy intensity data for a spreadsheet editor, and sum the intensity from all three bands for each sample, then calculate the percentage for each isoform relative to the total. Plot the percentages of each isoform, or the differences in the percentage relative to the untreated samples.A plasmid containing the minigene from E1A was used to observe the effect on alternative splicing by evaluating the proportion of mRNA from each isoform produced. Basal expression of E1A isoforms variants depended on the cell line and time of E1A expression. The HEK 293 stable cell line, or HEK 293 recombinase containing site, showed a higher expression of 13S in comparison to HeLa cells, but showed similar levels of 13S and 12S isoforms after 48 hours of E1A expression.Cells exposed to cisplatin showed a shift in five prime S-S splicing selection favoring 12S expression. This effect was observed in HEK 293 stably expressing the Flag empty vector, as well as isoform one of Nek4. Changes in alternative splicing after paclitaxel treatment were very discreet, but the directions of the changes were opposite in Flag and Nek4 expressing cells.When performing this protocol, it's important to use untransfected and non-reverse transcriptase controls to avoid misinterpretation with endogenous E1A expression, mainly when using HEK 293 cells. After obtaining positive results, the alternative splicing of specific genes related to the chemotherapeutic response can be evaluated. When some effect is observed, this simple protocol can direct these studies for more consistent pathways, where the protein plays a role regulating alternative splicing in chemotherapy response, for example.

using-the-e1a-minigene-tool-to-study-mrna-splicing-changes

Research

JoVE Journal

Cancer Research

Coculture Assays to Study Macrophage and Microglia Stimulation of Glioblastoma Invasion

Glioblastoma multiforme (grade IV glioma) is a very aggressive human cancer with a median survival of 1 year post diagnosis. Despite the increased understanding of the molecular events that give rise to glioblastomas, this cancer still remains highly refractory to conventional treatment. Surgical resection of high grade brain tumors is rarely complete due to the highly infiltrative nature of glioblastoma cells. Therapeutic approaches which attenuate glioblastoma cell invasion therefore is an attractive option. Our laboratory and others have shown that tumor associated macrophages and microglia (resident brain macrophages) strongly stimulate glioblastoma invasion. The protocol described in this paper is used to model glioblastoma-macrophage/microglia interaction using in vitro culture assays. This approach can greatly facilitate the development and/or discovery of drugs that disrupt the communication with the macrophages that enables this malignant behavior. We have established two robust coculture invasion assays where microglia/macrophages stimulate glioma cell invasion by 5 - 10 fold. Glioblastoma cells labelled with a fluorescent marker or constitutively expressing a fluorescent protein are plated without and with macrophages/microglia on matrix-coated polycarbonate chamber inserts or embedded in a three dimensional matrix. Cell invasion is assessed by using fluorescent microscopy to image and count only invasive cells on the underside of the filter. Using these assays, several pharmacological inhibitors (JNJ-28312141, PLX3397, Gefitinib, and Semapimod), have been identified which block macrophage/microglia stimulated glioblastoma invasion.

Understanding the malignant behavior of cancer requires creating accurate models of how tumor cells interact with components of the tumor microenvironment, such as macrophages. Here we describe two methods to study glioblastoma cell interaction with tumor associated macrophages and microglia where the effect on glioblastoma invasion is assessed.

Glioblastoma multiforme (grade IV glioma) is a very aggressive human cancer with a median survival of 1 year post diagnosis. Despite the increased ...

Conditional Knockdown of Gene Expression in Cancer Cell Lines to Study the Recruitment of Monocytes/Macrophages to the Tumor Microenvironment

siRNA and shRNA-mediated knock down (KD) methods of regulating gene expression are invaluable tools for understanding gene and protein function. However, in the case that the KD of the protein of interest has a lethal effect on cells or the anticipated effect of the KD is time-dependent, unconditional KD methods are not appropriate. Conditional systems are more suitable in these cases and have been the subject of much interest. These include Ecdysone-inducible overexpression systems, Cytochrome P-450 induction system1, and the tetracycline regulated gene expression systems. 
The tetracycline regulated gene expression system enables reversible control over protein expression by induction of shRNA expression in the presence of tetracycline. In this protocol, we present an experimental design using functional Tet-ON system in human cancer cell lines for conditional regulation of gene expression. We then demonstrate the use of this system in the study of tumor cell-monocyte interaction.

This protocol serves as a scheme for setting up a functional Tet-ON system in cancer cell lines and its subsequent use, in particular for studying the role of tumor cell-derived proteins in recruitment of monocytes/macrophages to the tumor microenvironment.

siRNA and shRNA-mediated knock down (KD) methods of regulating gene expression are invaluable tools for understanding gene and protein function. However, ...

Using the Dot Assay to Analyze Migration of Cell Sheets

Although complex organisms appear static, their tissues are under a continuous turnover. As cells age, die, and are replaced by new cells, cells move within tissues in a tightly orchestrated manner. During tumor development, this equilibrium is disturbed, and tumor cells leave the epithelium of origin to invade the local microenvironment, to travel to distant sites, and to ultimately form metastatic tumors at distant sites. The dot assay is a simple, two-dimensional unconstrained migration assay, to assess the net movement of cell sheets into a cell-free area, and to analyze parameters of cell migration using time-lapse imaging. Here, the dot assay is demonstrated using a human invasive, lung colony forming breast cancer cell line, MCF10CA1a, to analyze the cells' migratory response to epidermal growth factor (EGF), which is known to increase malignant potential of breast cancer cells and to alter the migratory phenotype of cells.

Cell migration is essential for development, tissue maintenance and repair, and tumorigenesis, and is regulated by growth factors, chemokines, and cytokines. This protocol describes the dot assay, a two-dimensional, unconstrained migration assay to assess the migratory phenotype of attached, cohesive cell sheets in response to microenvironmental cues.

Although complex organisms appear static, their tissues are under a continuous turnover. As cells age, die, and are replaced by new cells, cells move ...

Dried Blood and Serum Spots As A Useful Tool for Sample Storage to Evaluate Cancer Biomarkers

Blood sample quality is crucial to ensure accurate downstream analyses such as real-time PCR or ELISA. Correct storage of biological materials is the starting point to achieve reproducible and reliable results. All samples should be treated in the same way from blood collection to storage. Depending on the analyses to be performed, whole blood and serum samples should be stored at -20 &#176;C or -80 &#176;C until use. Blood/serum samples should also be aliquoted to avoid multiple freeze-thawing. Another important issue is the sample conditions during shipment from one laboratory to another. If dry ice is not available or the shipment takes longer than a few days, alternative approaches are needed. One option is to use filter paper for blood collection. Here, we propose a method for blood and serum sample collection that takes advantage of dried blood spots (DBS) and dried serum spots (DSS). We developed the procedure to extract DNA from DBS for the downstream evaluation of some single nucleotide polymorphisms (SNPs) by real time PCR. We also optimized an ELISA assay starting from proteins eluted from DSS. This method can be used with other ELISA assays or procedures evaluating proteins.

This protocol describes a simple and useful method to store peripheral blood and serum/plasma for downstream analyses such as single nucleotide polymorphism (SNP) evaluation and ELISA assay.

Blood sample quality is crucial to ensure accurate downstream analyses such as real-time PCR or ELISA. Correct storage of biological materials is the ...

Utilizing 18F-FDG PET/CT Imaging and Quantitative Histology to Measure Dynamic Changes in the Glucose Metabolism in Mouse Models of Lung Cancer

A hallmark of advanced tumors is a switch to aerobic glycolysis that is readily measured by [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) imaging. Co-mutations in the KRAS proto-oncogene and the LKB1 tumor suppressor gene are frequent events in lung cancer that drive hypermetabolic, glycolytic tumor growth. A critical pathway regulating the growth and metabolism of these tumors is the mechanistic target of the rapamycin (mTOR) pathway, which can be effectively targeted using selective catalytic mTOR kinase inhibitors. The mTOR inhibitor MLN0128 suppresses glycolysis in mice bearing tumors with Kras and Lkb1 co-mutations, referred to as KL mice. The therapy response in KL mice is first measured by 18F-FDG PET and computed tomography (CT) imaging before and after the delivery of MLN0128. By utilizing 18F-FDG PET/CT, researchers are able to measure dynamic changes in the glucose metabolism in genetically engineered mouse models (GEMMs) of lung cancer following a therapeutic intervention with targeted therapies. This is followed by ex vivo autoradiography and a quantitative immunohistochemical (qIHC) analysis using morphometric software. The use of qIHC enables the detection and quantification of distinct changes in the biomarker profiles following treatment as well as the characterization of distinct tumor pathologies. The coupling of PET imaging to quantitative histology is an effective strategy to identify metabolic and therapeutic responses in vivo in mouse models of disease.

Utilizing 18F-FDG PET/CT Imaging and Quantitative Histology to Measure Dynamic Changes in the Glucose Metabolism in Mouse Models of Lung Cancer

In this protocol, we describe how to utilize [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography and computed tomography (18F-FDG PET/CT) imaging to measure the tumor metabolic response to the targeted therapy MLN0128 in a Kras/Lkb1 mutant mouse model of lung cancer and coupled imaging with high resolution ex vivo autoradiography and quantitative histology.

A hallmark of advanced tumors is a switch to aerobic glycolysis that is readily measured by [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography ...

A Syngeneic Pancreatic Cancer Mouse Model to Study the Effects of Irreversible Electroporation

Pancreatic cancer (PC), a disease which kills approximately 40,000 patients each year in the US, has successfully evaded several therapeutic approaches including the promising immunotherapeutic strategies. Irreversible electroporation (IRE) is a non-thermal ablation technique that induces tumor cell death without destruction of adjacent collagenous structures, thus enabling the procedure to be performed in tumors very close to blood vessels. Unlike thermal ablation techniques, IRE results in gradual apoptotic cell death, along with immediate ablation induced necrosis, and is currently in clinical use for selected patients with locally advanced PC. An ablative, non-target specific procedure like IRE can induce a myriad of responses in the tumor microenvironment. A few studies have addressed the effects of IRE on tumor growth in other tumor types, but none have focused on PC. We have developed a syngeneic mouse model of PC in which subcutaneous (SQ) and orthotopic tumors can be successfully treated with IRE in a highly controlled setting, facilitating various longitudinal studies post procedure. This animal model serves as a robust system to study the effects of IRE and ways to improve the clinical efficacy of IRE.

Irreversible electroporation (IRE) is a non-thermal ablation technique used for the treatment of locally advanced pancreatic cancer. Being a relatively new technique, the effects of IRE on the tumor growth are poorly understood. We have developed a syngeneic mouse model that facilitates studying the effects of IRE on pancreatic cancer.

Pancreatic cancer (PC), a disease which kills approximately 40,000 patients each year in the US, has successfully evaded several therapeutic approaches ...

Live-Cell Imaging Assays to Study Glioblastoma Brain Tumor Stem Cell Migration and Invasion

Glioblastoma (GBM) is an aggressive brain tumor that is poorly controlled with the currently available treatment options. Key features of GBMs include rapid proliferation and pervasive invasion into the normal brain. Recurrence is thought to result from the presence of radio- and chemo-resistant brain tumor stem cells (BTSCs) that invade away from the initial cancerous mass and, thus, evade surgical resection. Hence, therapies that target BTSCs and their invasive abilities may improve the otherwise poor prognosis of this disease. Our group and others have successfully established and characterized BTSC cultures from GBM patient samples. These BTSC cultures demonstrate fundamental cancer stem cell properties such as clonogenic self-renewal, multi-lineage differentiation, and tumor initiation in immune-deficient mice. In order to improve on the current therapeutic approaches for GBM, a better understanding of the mechanisms of BTSC migration and invasion is necessary. In GBM, the study of migration and invasion is restricted, in part, due to the limitations of existing techniques which do not fully account for the in vitro growth characteristics of BTSCs grown as neurospheres. Here, we describe rapid and quantitative live-cell imaging assays to study both the migration and invasion properties of BTSCs. The first method described is the BTSC migration assay which measures the migration toward a chemoattractant gradient. The second method described is the BTSC invasion assay which images and quantifies a cellular invasion from neurospheres into a matrix. The assays described here are used for the quantification of BTSC migration and invasion over time and under different treatment conditions.

Here, we describe live-cell imaging techniques to quantitatively measure the migration and invasion of glioblastoma brain tumor stem cells over time and under multiple treatment conditions.

Glioblastoma (GBM) is an aggressive brain tumor that is poorly controlled with the currently available treatment options. Key features of GBMs include ...

In Vitro Assay to Study Tumor-macrophage Interaction

Tumor associated macrophages (TAMs) account for a large percentage of cells in the tumor mass for different types of cancers. Glioblastoma (GBM), a malignant brain tumor with no cure, has up to a half the tumor mass TAMs. TAMs can be pro-tumoral or anti-tumoral, depending on the activation of specific genes in the cells. Genetic mutations in the tumors, through regulating cytokine expression, can affect recruitment of TAMs to the tumor microenvironment. Here, we describe a quantitative cell-based assay to assess macrophage recruitment by the conditioned medium from the tumor cells. This assay uses the human macrophage cell line MV-4-11 to study macrophage attraction by the conditioned medium from glioblastoma, allowing for high reproducibility and low variability. Data generated with this assay can contribute to a better understanding of the interaction between the tumor and the tumor microenvironment. Similar assay can be used to assess interaction between the tumor cells and other immune cells, including T cells and natural killer (NK) cells.

This article represents a useful in vitro assay to evaluate the capability of conditioned medium from tumor cells to attract macrophages.

Tumor associated macrophages (TAMs) account for a large percentage of cells in the tumor mass for different types of cancers. Glioblastoma (GBM), a ...

Using the Chicken Chorioallantoic Membrane In Vivo Model to Study Gynecological and Urological Cancers

Mouse models are the benchmark tests for in vivo cancer studies. However, cost, time, and ethical considerations have led to calls for alternative in vivo cancer models. The chicken chorioallantoic membrane (CAM) model provides an inexpensive, rapid alternative that permits direct visualization of tumor development and is suitable for in vivo imaging. As such, we sought to develop an optimized protocol for engrafting gynecological and urological tumors into this model, which we present here. Approximately 7 days postfertilization, the air cell is moved to the vascularized side of the egg, where an opening is created in the shell. Tumors from murine and human cell lines and primary tissues can then be engrafted. These are typically seeded in a mixture of extracellular matrix and medium to avoid cellular dispersal and provide nutrient support until the cells recruit a vascular supply. Tumors may then grow for up to an additional 14 days prior to the eggs hatching. By implanting cells stably transduced with firefly luciferase, bioluminescence imaging can be used for the sensitive detection of tumor growth on the membrane and cancer cell spread throughout the embryo. This model can potentially be used to study tumorigenicity, invasion, metastasis, and therapeutic effectiveness. The chicken CAM model requires significantly less time and financial resources compared to traditional murine models. Because the eggs are immunocompromised and immune tolerant, tissues from any organism can potentially be implanted without costly transgenic animals (e.g., mice) required for implantation of human tissues. However, many of the advantages of this model could potentially also be limitations, including the short tumor generation time and immunocompromised/immune tolerant status. Additionally, although all tumor types presented here engraft in the chicken chorioallantoic membrane model, they do so with varying degrees of tumor growth.

We present the chicken chorioallantoic membrane model as an alternative, transplantable, in vivo model for the engraftment of gynecological and urological cancer cell lines and patient-derived tumors.

Mouse models are the benchmark tests for in vivo cancer studies. However, cost, time, and ethical considerations have led to calls for alternative in vivo ...

Portal Vein Injection of Colorectal Cancer Organoids to Study the Liver Metastasis Stroma

Hepatic metastasis of colorectal cancer (CRC) is a leading cause of cancer-related death. Cancer-associated fibroblasts (CAFs), a major component of the tumor microenvironment, play a crucial role in metastatic CRC progression and predict poor patient prognosis. However, there is a lack of satisfactory mouse models to study the crosstalk between metastatic cancer cells and CAFs. Here, we present a method to investigate how liver metastasis progression is regulated by the metastatic niche and possibly could be restrained by stroma-directed therapy. Portal vein injection of CRC organoids generated a desmoplastic reaction, which faithfully recapitulated the fibroblast-rich histology of human CRC liver metastases. This model was tissue-specific with a higher tumor burden in the liver when compared to an intra-splenic injection model, simplifying mouse survival analyses. By injecting luciferase-expressing tumor organoids, tumor growth kinetics could be monitored by in vivo imaging. Moreover, this preclinical model provides a useful platform to assess the efficacy of therapeutics targeting the tumor mesenchyme. We describe methods to examine whether adeno-associated virus-mediated delivery of a tumor-inhibiting stromal gene to hepatocytes could remodel the tumor microenvironment and improve mouse survival. This approach enables the development and assessment of novel therapeutic strategies to inhibit hepatic metastasis of CRC.

Portal vein injection of colorectal cancer (CRC) organoids generates stroma-rich liver metastasis. This mouse model of CRC hepatic metastasis represents a useful tool to study tumor-stroma interactions and develop novel stroma-directed therapeutics such as adeno-associated virus-mediated gene therapies.

Hepatic metastasis of colorectal cancer (CRC) is a leading cause of cancer-related death. Cancer-associated fibroblasts (CAFs), a major component of the ...