Name: monitoring hippo signaling pathway activity using a luciferase-based large tumor suppressor (lats) biosensor
Uploaded: 2018-09-13T15:00:00
Description: Watch this Scientific Journal Video about Monitoring Hippo Signaling Pathway Activity Using a Luciferase-based Large Tumor Suppressor LATS Biosensor at JoVE.com

This work was supported by grants from the Canadian Institute of Health Research (CIHR#119325, 148629) and the Canadian Breast Cancer Foundation (CBCF) to XY. TA is supported by the Vanier Canada Graduate Scholarship and the Ontario International Graduate Scholarship. HJJVR is supported by a Queen Elizabeth II Graduate Scholarship in Science and Technology.

1. Investigation of a Putative Regulator of Hippo Signaling Using the LATS-BS
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	<li>Plating and transfection of cells
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		<li>Preparation of cell culture
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			<li>Warm 1x PBS, DMEM containing 10% FBS and 1% penicillin/streptomycin, and 0.25% trypsin-EDTA to 37 &#176;C in a water bath for approximately 30 min.</li>
			<li>Thoroughly clean a biosafety cabinet with 70% ethanol.</li>
			<li>Place tissue culture dishes, Pasteur pipettes, serological pipettes, and pipette tips into the tissue cu...

<ol>
	<li>Justice, R. W., Zilian, O., Woods, D. F., Noll, M., Bryant, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Drosophila+tumor+suppressor+gene+warts+encodes+a+homolog+of+human+myotonic+dystrophy+kinase+and+is+required+for+the+control+of+cell+shape+and+proliferation.">The Drosophila tumor suppressor gene warts encodes a homolog of human myotonic dystrophy kinase and is required for the control of cell shape and proliferation.</a> Genes &amp; Development. 9 (5), 534-546 (1995).</li><li>Xu, T., Wang, W., Zhang, S., Stewart, R. A., Yu, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identifying+tumor+suppressors+in+genetic+mosaics:+the+Drosophila+lats+gene+encodes+a+putative+protein+kinase.">Identifying tumor suppressors in genetic mosaics: the Drosophila lats gene encodes a putative protein kinase.</a> Development. 121 (4), 1053-1063 (1995).</li><li>Taha, Z., Janse van Rensburg, H. 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J., Yang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+roles+of+the+Hippo+pathway+in+cancer+metastasis.">The roles of the Hippo pathway in cancer metastasis.</a> Cellular Signalling. 28 (11), 1761-1772 (2016).</li><li>Yeung, B., Yu, J., Yang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Roles+of+the+Hippo+pathway+in+lung+development+and+tumorigenesis.">Roles of the Hippo pathway in lung development and tumorigenesis.</a> International Journal of Cancer. 138 (3), 533-539 (2016).</li><li>Zhao, Y., Yang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Hippo+pathway+in+chemotherapeutic+drug+resistance.">The Hippo pathway in chemotherapeutic drug resistance.</a> International Journal of Cancer. 137 (12), 2767-2773 (2015).</li><li>Yu, F. -. 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K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+visualization+of+multiple+protein+interactions+in+living+cells+using+multicolor+fluorescence+complementation+analysis.">Simultaneous visualization of multiple protein interactions in living cells using multicolor fluorescence complementation analysis.</a> Nature Biotechnology. 21 (5), 539-545 (2003).</li><li>Hosseinkhani, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+enigma+of+multicolor+bioluminescence+of+firefly+luciferase.">Molecular enigma of multicolor bioluminescence of firefly luciferase.</a> Cellular and Molecular Life Sciences. 68 (7), 1167-1182 (2011).</li><li>Paulmurugan, R., Gambhir, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combinatorial+library+screening+for+developing+an+improved+split-firefly+luciferase+fragment-assisted+complementation+system+for+studying+protein-protein+interactions.">Combinatorial library screening for developing an improved split-firefly luciferase fragment-assisted complementation system for studying protein-protein interactions.</a> Analytical Chemistry. 79 (6), 2346-2353 (2007).</li><li>Azad, 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=A+LATS+biosensor+screen+identifies+VEGFR+as+a+regulator+of+the+Hippo+pathway+in+angiogenesis.">A LATS biosensor screen identifies VEGFR as a regulator of the Hippo pathway in angiogenesis.</a> Nature Communications. 9 (1), 1061 (2018).</li><li>Moroishi, 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=A+YAP/TAZ-induced+feedback+mechanism+regulates+Hippo+pathway+homeostasis.">A YAP/TAZ-induced feedback mechanism regulates Hippo pathway homeostasis.</a> Genes &amp; Development. 29 (12), 1271-1284 (2015).</li></ol>

While the Hippo pathway plays critical roles in various biological processes, and dysregulation of the Hippo pathway leads to cancer6, how the Hippo pathway is regulated in response to various stimuli is not completely understood. In addition, there has been no quantitative and real-time system to assess the activity of core Hippo components. Recently, we developed and validated a novel biosensor for measuring LATS kinase activity in the Hippo pathway24. This biosensor can ...

The Hippo signaling pathway was first identified in Drosophila as a novel regulator of cell growth and animal size1,2. Since its initial discovery, mounting evidence has convincingly shown that the Hippo pathway plays critical roles in the development (e.g., early embryonic development, organ size control, and three-dimensional [3-D] morphology), tumorigenesis (e.g., tumor development, metastasis, angiogenesis, immune evasion, genomic instability, stress response, and drug resistance), and tissue homeostasis (e.g., stem cell renewal and differentiation and tissue regeneration after injury)3,4,5,6,7,8,9,10. Hippo signaling is frequently dysregulated in various cancers7,8,9,10,11,12. Therefore, elucidating functions of the Hippo pathway in cancer biology and therapeutics and regenerative medicine has become one of the hottest areas in biomedical research.
In brief, in the Hippo pathway, upon activation by upstream regulators (e.g., cell-cell contact, nutrient stress, and extracellular matrix [ECM]), MST1/2 (MST; mammalian homologs of Drosophila Hippo) serine/threonine (S/T) kinases phosphorylate/activate adaptor proteins hMOB1 and WW45, as well as LATS1/2 (LATS) kinases which, subsequently, phosphorylate transcriptional co-activator YAP and its paralog TAZ at conserved HX(H/R/K)XX(S/T) (H, histidine; R, arginine; K, lysine; S, serine; T, threonine; X, any amino acids) motifs, including YAP-S127 and TAZ-S8911,12. S127-phosphorylated YAP (YAP-pS127) and S89-phosphorylated TAZ (TAZ-pS89) are degraded by ubiquitination or bind to cytoplasmic protein 14-3-3 and are prevented from interacting with TEAD1-4 transcription factors in the nucleus to transactivate downstream genes involved in the cell proliferation and apoptosis (Figure 1). Despite the tremendous interest in the Hippo pathway, few tools for measuring Hippo signaling exist and those that do have been historically limited to reporters of YAP/TAZ/TEAD transcriptional output. Indeed, until very recently, there were no tools for measuring the dynamics and activity of the Hippo signaling components in a quantitative, real-time, high-throughput, and non-invasive manner both in vitro and in vivo.
Given our emerging understanding of the role of protein-protein interactions in physiology and pathology, there is great interest in the development of tools that can be used to study these interactions in a quantitative and real-time manner13,14,15,16. Indeed, there has been significant progress in the development of bio-analytical strategies, including the yeast two-hybrid (Y2H)17, the surface plasmon resonance (SPR)18, and F&#246;rster resonance energy transfer (FRET)19 assays, to evaluate protein-protein interactions. However, these approaches carry the limitation of requiring significant optimization of the reporter orientation, such that many constructs must be tested to find an efficient one. Further, these approaches also have a relatively low signal-to-noise ratio, such that discerning a true positive signaling can be challenging.
Protein complementation assays were developed to overcome these limitations. The first generation of protein complementation assays was based on split multicolor fluorescence proteins and could not solve the aforementioned limitations20. Multicolor fluorescence proteins consist of only one domain, making it difficult to split them into two separate stable fragments with low affinity and background noise21. Subsequently, firefly luciferase was identified as a new candidate for use in developing split protein complementation assays. In this approach, firefly luciferase is split into two fragments (N-terminal and C-terminal luciferase [NLuc and CLuc]) with each fragment fused to a target protein of interest. If the NLuc and CLuc are brought into proximity upon the interaction of the two target proteins, luciferase activity is reconstituted and bioluminescent light is generated in the presence of luciferin substrate and ATP22. In 2001, by performing a combinatorial screening using a library containing NLuc and CLuc fragments cut at various sites and attached to proteins with different linkers, Paulmurugan and Gambhir at Stanford University developed an optimized split-firefly luciferase fragment-assisted complementation system for protein-protein interactions23. In this system, firefly luciferase is cut at amino acid (aa) 398 to form NLuc and CLuc, which are attached to two proteins of interest using a flexible linker of eight glycine residues and two serine residues.
Using a similar approach, we recently developed a new LATS-BS by fusing NLuc to 15 aa of YAP surrounding the LATS phosphorylation site at S127 (YAP15) and CLuc with 14-3-3. The full-length YAP protein was not used, to avoid confounding signals by post-translational modifications of YAP (e.g., phosphorylation at other sites and ubiquitination) by other upstream regulators. The LATS-BS presented here can non-invasively monitor Hippo signaling activity both in vitro in living cells and in vivo in mice20,24 (Figure 2). Here, we describe a detailed protocol for measuring LATS kinase activity in vitro using the LATS-BS. First, we show how the LATS-BS can be used to investigate the effect of an overexpressed protein on LATS activity. Then, we show how the biosensor can be used to monitor the activity of the Hippo pathway after treatment with agents regulating the Hippo pathway. This protocol could be used to identify and characterize signaling pathways or stimuli regulating LATS kinase activity.

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			<td height="42" style="height:42px;width:267px;">Trypsin-EDTA&#160;</td>
			<td style="width:121px;">Life Technologies</td>
			<td style="width:91px;">2520056</td>
			<td style="width:213px;">0.25%</td>
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			<td height="21" style="height:21px;">Fetal Bovine Serum (FBS)</td>
			<td style="width:121px;">Sigma</td>
			<td style="width:91px;">F1051</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">DMEM</td>
			<td style="width:121px;">Sigma</td>
			<td style="width:91px;">D6429-500ml</td>
			<td>DMEM with high glucose&#160;</td>
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			<td height="42" style="height:42px;width:267px;">Penicillin Streptomycin</td>
			<td style="width:121px;">Life Technologies</td>
			<td style="width:91px;">15140122</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PolyJet In Vitro DNA Transfection Reagent&#160;</td>
			<td style="width:121px;">Signagen</td>
			<td style="width:91px;">SL100688.5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:267px;">5x Passive lysis buffer</td>
			<td style="width:121px;">Promega</td>
			<td style="width:91px;">E194A</td>
			<td>30 ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:267px;">Dual-Glo&#174; Luciferase Assay System</td>
			<td style="width:121px;">Promega</td>
			<td style="width:91px;">E2940</td>
			<td>100 ml kit</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:267px;">20/20 luminometer</td>
			<td style="width:121px;">Turner Biosystems</td>
			<td style="width:91px;">998-2036</td>
			<td>Single tube reader luminometer</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:267px;">GloMax&#174;Navigator with dual injectors</td>
			<td style="width:121px;">Promega</td>
			<td style="width:91px;">GM2010</td>
			<td>96-well plates reader luminometer</td>
		</tr>
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monitoring hippo signaling pathway activity using a luciferase-based large tumor suppressor (lats) biosensor

The Hippo signaling pathway is a conserved regulator of organ size and has important roles in the development and cancer biology. Due to technical challenges, it remains difficult to assess the activity of this signaling pathway and interpret it within a biological context. The existing literature on large tumor suppressor (LATS) relies on methods that are qualitative and cannot easily be scaled-up for screening. Recently, we have developed a bioluminescence-based biosensor to monitor the kinase activity of LATS-a core component of the Hippo kinase cascade. Here, we describe procedures for how this LATS biosensor (LATS-BS) can be used to characterize Hippo pathway regulators. First, we provide a detailed protocol for investigating the effect of an overexpressed protein candidate (e.g., VEGFR2) on LATS activity using the LATS-BS. Then, we show how the LATS-BS can be used for a small-scale kinase inhibitor screen. This protocol can feasibly be scaled-up to perform larger screens, which undoubtedly will identify novel regulators of the Hippo pathway.

The LATS-BS was cotransfected with different genes to evaluate their effect on LATS activity (Figure 3). In this experiment, Renilla was used as an internal control. The transient expression of YAP-5SA, a constitutive active form of YAP, causes increasing levels of YAP transcriptional targets and a subsequent increase in LATS kinase activity through an established feedback pathway25. MST, the upstream activator of LATS in the ...

Watch this Scientific Journal Video about Monitoring Hippo Signaling Pathway Activity Using a Luciferase-based Large Tumor Suppressor LATS Biosensor at JoVE.com

Monitoring Hippo Signaling Pathway Activity Using a Luciferase-based Large Tumor Suppressor LATS Biosensor

Here we present a luciferase-based biosensor to quantify the kinase activity of large tumor suppressor (LATS)-a central kinase in the Hippo signaling pathway. This biosensor has diverse applications in basic and translational research aimed at investigating Hippo pathway regulators in vitro and in vivo.

Monitoring Hippo Signaling Pathway Activity Using a Luciferase-based Large Tumor Suppressor (LATS) Biosensor

The Hippo signaling pathway is a conserved regulator of organ size and has important roles in the development and cancer biology. Due to technical ...

My lab has been studying the role of Hippo pathway in breast and lung cancer, and recently, we have developed a novel biosensor to monitor Hippo signaling activity. This method can be used to answer key questions about cellular signaling networks, such as how the Hippo pathway responds to factors and how it interacts with other signaling pathways. The main advantage of this technique over existing methods is its great sensitivity and also the large number of the samples can be processed quickly and simultaneously.This technique has diverse applications in basic and translational research to investigate regulators of the Hippo signaling pathway both in vitro and in vivo. To begin, mini-prep LATS-BS plasmids fresh from DH5-Alpha bacteria liquid culture. An hour prior to transfection, aspirate the medium from the plate, and add 500 microliters of growth medium to each well.One important point is that LATS biosensor must be prepared fresh in order to get maximum expression and activity. Also, it is recommended to always use an upstream regulator of the Hippo pathway, such as MSD, as a positive control when performing luciferase assay. After this, return the cells to the incubator.Next, prepare solution A, a DNA solution, and solution B, a diluted polymer-based transfection reagent, as described in the text protocol. After this, immediately add solution B to solution A, and gently pipette up and down to mix. Incubate the sample at room temperature for 15 minutes to allow the transfection complexes to form.Then add the total volume of transfection complexes drop-wise to each well of the plate with gentle swirling. Incubate the cells overnight at 37 degrees Celsius. The next day, remove the transfection complex-containing media and replace it with fresh complete media.Then culture the cells at 37 degrees Celsius for one more day. Dilute an appropriate amount of 5x Passive lysis buffer with distilled water. Then, completely aspirate the media from the plate.Add one milliliter of PBS to each well, and swirl the plate gently to remove detached cells and residual growth media. Then aspirate the PBS completely. Next, add 250 microliters of 1xPLB to each well.Place the culture plate on a rocking platform for 15 minutes to ensure even coverage of the cell monolayer with PLB. After this, transfer the lysate to a 1.5 milliliter microcentrifuge tube. Remove the LAR-2 from 80 degrees Celsius storage, and equilibrate it to room temperature.Then, prepare Renilla detection reagent for an appropriate quantity of assays. Add the Renilla detection reagent to 50x substrate and its buffer. Next, dispense 10 microliters of each cell lysate into 1.5 milliliter tubes.Then, program a luminometer to perform a two second pre-measurement delay, followed by a 10 second measurement period. Carefully, transfer 20 microliters of LAR-2 reagent into one tube, and quickly pipette up and down to mix. Then, immediately place the tube in the luminometer and initiate the reading.After the reading, remove the sample tube from the luminometer, add 20 microliters of Renilla reagent, and pipette up and down to mix. Then, place the sample in the luminometer and initiate the next reading. First, culture, detach, count, and plate HEK293 Ad-cells as described in the text protocol.Then, one hour before transfection, aspirate the media from the plate and replace it with five milliliters of fresh complete growth media. Finally, add diluted solution B to solution A, and pipette up and down to mix. Then, incubate the sample at room temperature for 15 minutes before adding the total volume of the transfection complexes to the plate, while swirling gently.Incubate the cells overnight at 37 degrees Celsius. The next day, trypsinize and count the cells. Plate 10, 000 to 20, 000 cells into each well of a 96-well plate in a total volume of 100 microliters of media per well.After this, incubate the cells for one more day. One to four hours prior to performing the luciferase assay, add agents potentially regulating the Hippo pathway, at a final concentration of 10 micromolar per well. Next, aspirate the media completely from the cells and wash the cells in each well with 100 microliters of PBS.Then, add 20 microliters of PLB to each well. Place the culture plate on a rocking platform for 15 minutes. Then, transfer 20 microliters of LAR-2 reagent to each well of the plate, and pipette up and down to mix.Immediately after this, place the plate into a plate-reading luminometer and initiate the reading. In the first part of this protocol, the LATS-BS was cotransfected with different genes to evaluate their effect on LATS kinase activity. In the second protocol, LATS-BS was transfected into HEK293-Ad, and the cells were passed into 96-well plates.40 hours after transfection, the cells were treated with different known small molecule regulators of Hippo signaling, followed by a luciferase assay. When interpreting the results of these assays, it should be noted that proteins and drug treatments may activate feedback pathways that influence biosensor activity. Further experiments will be necessary to confirm a relationship between the candidate and the Hippo signaling pathway.Following this procedure, other methods like quantitative Real-Time PCR, or Western Blot, can be used to answer additional questions about LATS kinase activity. After its development, this technique paved the way for the researchers in the field of cancer biology to explore the dynamics and activity of LATS kinase and Hippo signaling pathway in many biological and biochemical processes. Don't forget that drugs for screening can be extremely hazardous, and appropriate precautions should always be taken while performing this procedure.

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Cancer Research

A Murine Orthotopic Bladder Tumor Model and Tumor Detection System

This protocol describes the generation of bladder tumors in female C57BL/6J mice using the murine bladder cancer cell line MB49, which has been modified to secrete human Prostate Specific Antigen (PSA), and the procedure for the confirmation of tumor implantation. In brief, mice are anesthetized using injectable drugs and are made to lay in the dorsal position. Urine is vacated from the bladder and 50 &#181;L of poly-L-lysine (PLL) is slowly instilled at a rate of 10 &#181;L/20 s using a 24 G IV catheter. It is left in the bladder for 20 min by stoppering the catheter. The catheter is removed and PLL is vacated by gentle pressure on the bladder. This is followed by instillation of the murine bladder cancer cell line (1 x 105 cells/50 &#181;L) at a rate of 10 &#181;L/20 s. The catheter is stoppered to prevent premature evacuation. After 1 h, the mice are revived with a reversal drug, and the bladder is vacated. The slow instillation rate is important, as it reduces vesico-ureteral reflux, which can cause tumors to occur in the upper urinary tract and in the kidneys. The cell line should be well re-suspended to reduce clumping of cells, as this can lead to uneven tumor sizes after implantation.
This technique induces tumors with high efficiency. Tumor growth is monitored by urinary PSA secretion. PSA marker monitoring is more reliable than ultrasound or fluorescence imaging for the detection of the presence of tumors in the bladder. Tumors in mice generally reach a maximum size that negatively impacts health by about 3 - 4 weeks if left untreated. By monitoring tumor growth, it is possible to differentiate mice that were cured from those that were not successfully implanted with tumors. With only end-point analysis, the latter may be mistakenly assumed to have been cured by therapy.

This protocol describes the generation of murine orthotopic bladder tumors in female C57BL/6J mice and the monitoring of tumor growth.

This protocol describes the generation of bladder tumors in female C57BL/6J mice using the murine bladder cancer cell line MB49, which has been modified ...

Characterization of Tumor Cells Using a Medical Wire for Capturing Circulating Tumor Cells: A 3D Approach Based on Immunofluorescence and DNA FISH

Circulating tumor cells (CTCs) are associated with poor survival in metastatic cancer. Their identification, phenotyping, and genotyping could lead to a better understanding of tumor heterogeneity and thus facilitate the selection of patients for personalized treatment. However, this is hampered because of the rarity of CTCs. We present an innovative approach for sampling a high volume of the patient blood and obtaining information about presence, phenotype, and gene translocation of CTCs. The method combines immunofluorescence staining and DNA fluorescent-in-situ-hybridization (DNA FISH) and is based on a functionalized medical wire. This wire is an innovative device that permits the in vivo isolation of CTCs from a large volume of peripheral blood. The blood volume screened by a 30-min administration of the wire is approximately 1.5-3 L. To demonstrate the feasibility of this approach, epithelial cell adhesion molecule (EpCAM) expression and the chromosomal translocation of the ALK gene were determined in non-small-cell lung cancer (NSCLC) cell lines captured by the functionalized wire and stained with an immuno-DNA FISH approach. Our main challenge was to perform the assay on a 3D structure, the functionalized wire, and to determine immuno-phenotype and FISH signals on this support using a conventional fluorescence microscope. The results obtained indicate that catching CTCs and analyzing their phenotype and chromosomal rearrangement could potentially represent a new companion diagnostic approach and provide an innovative strategy for improving personalized cancer treatments.

We present a new approach to characterize tumor cells. We combined immunofluorescence with DNA fluorescent-in-situ-hybridization to evaluate cells captured by a functionalized medical wire capable of in vivo enriching CTCs directly from patient blood.

Circulating tumor cells (CTCs) are associated with poor survival in metastatic cancer. Their identification, phenotyping, and genotyping could lead to a ...

Live Cell Imaging of the TGF-	&beta;/Smad3 Signaling Pathway In Vitro and In Vivo Using an Adenovirus Reporter System

Transforming Growth Factor &#946; (TGF-&#946;) signaling regulates many important functions required for cellular homeostasis and is commonly found overexpressed in many diseases, including cancer. TGF-&#946; is strongly implicated in metastasis during late stage cancer progression, activating a subset of migratory and invasive tumor cells. Current methods for signaling pathway analysis focus on endpoint models, which often attempt to measure signaling post-hoc of the biological event and do not reflect the progressive nature of the disease. Here, we demonstrate a novel adenovirus reporter system specific for the TGF-&#946;/Smad3 signaling pathway that can detect transcriptional activation in live cells. Utilizing an Ad-CAGA12-Td-Tom reporter, we can achieve a 100% infection rate of MDA-MB-231 cells within 24 h in vitro. The use of a fluorescent reporter allows for imaging of live single cells in real-time with direct identification of transcriptionally active cells. Stimulation of infected cells with TGF-&#946; displays only a subset of cells that are transcriptionally active and involved in specific biological functions. This approach allows for high specificity and sensitivity at a single cell level to enhance understanding of biological functions related to TGF-&#946; signaling in vitro. Smad3 transcriptional activity can also be reported in vivo in real-time through the application of an Ad-CAGA12-Luc reporter. Ad-CAGA12-Luc can be measured in the same manner as traditional stably transfected luciferase cell lines. Smad3 transcriptional activity of cells implanted in vivo can be analyzed through conventional IVIS imaging and monitored live during tumor progression, providing unique insight into the dynamics of the TGF-&#946; signaling pathway. Our protocol describes an advantageous reporter delivery system allowing for quick high-throughput imaging of live cell signaling pathways both in vitro and in vivo. This method can be expanded to a range of image based assays and presents as a sensitive and reproducible approach for both basic biology and therapeutic development.

Live Cell Imaging of the TGF-	&amp;beta;/Smad3 Signaling Pathway &lt;em&gt;In Vitro&lt;/em&gt; and &lt;em&gt;In Vivo&lt;/em&gt; Using an Adenovirus Reporter System

Here, we present a protocol for live cell imaging of TGF-&#946;/Smad3 signaling activity using an adenovirus reporter system. This system tracks transcriptional activity in real-time and can be applied to both single cells in vitro and in live animalmodels.

Transforming Growth Factor &#946; (TGF-&#946;) signaling regulates many important functions required for cellular homeostasis and is commonly found ...

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 ...

Longitudinal Morphological and Physiological Monitoring of Three-dimensional Tumor Spheroids Using Optical Coherence Tomography

Tumor spheroids have been developed as a three-dimensional (3D) cell culture model in cancer research and anti-cancer drug discovery. However, currently, high-throughput imaging modalities utilizing bright field or fluorescence detection, are unable to resolve the overall 3D structure of the tumor spheroid due to limited light penetration, diffusion of fluorescent dyes and depth-resolvability. Recently, our lab demonstrated the use of optical coherence tomography (OCT), a label-free and non-destructive 3D imaging modality, to perform longitudinal characterization of multicellular tumor spheroids in a 96-well plate. OCT was capable of obtaining 3D morphological and physiological information of tumor spheroids growing up to about 600 &#181;m in height. In this article, we demonstrate a high-throughput OCT (HT-OCT) imaging system that scans the whole multi-well plate and obtains 3D OCT data of tumor spheroids automatically. We describe the details of the HT-OCT system and construction guidelines in the protocol. From the 3D OCT data, one can visualize the overall structure of the spheroid with 3D rendered and orthogonal slices, characterize the longitudinal growth curve of the tumor spheroid based on the morphological information of size and volume, and monitor the growth of the dead-cell regions in the tumor spheroid based on optical intrinsic attenuation contrast. We show that HT-OCT can be used as a high-throughput imaging modality for drug screening as well as characterizing biofabricated samples.

Optical coherence tomography (OCT), a three-dimensional imaging technology, was used to monitor and characterize the growth kinetics of multicellular tumor spheroids. Precise volumetric quantification of tumor spheroids using a voxel counting approach, and label-free dead tissue detection in the spheroids based on intrinsic optical attenuation contrast, were demonstrated.

Tumor spheroids have been developed as a three-dimensional (3D) cell culture model in cancer research and anti-cancer drug discovery. However, currently, ...

Predicting In Vivo Payloads Delivery using a Blood-brain Tumor-barrier in a Dish

Highly selective by nature, the blood-brain barrier (BBB) is essential for the brain homeostasis in physiological conditions. However, in the context of brain tumors, the molecular selectivity of BBB also shields the neoplastic cells by blocking the delivery of peripherally administered chemotherapies. The development of novel drugs (including nanoparticles) targeting malignant brain tumors ideally requires the use of preclinical animal models to study the drug&#8217;s transcytosis and antitumor efficacy. In order to comply with the 3R principle (refine, reduce, and replace) to reduce the number of laboratory animals in experimental setup and perform the high-throughput screening of a large library of antitumor agents, we developed a reproducible in vitro human and murine mimic of the blood-brain tumor-barrier (BBTB) using three-layered cultures of endothelial cells, astrocytes, and patient-derived glioblastoma spheres. For higher scalability and reproducibility, commercial cell lines or immortalized cells have been used in tailored conditions to allow the formation of a barrier resembling the actual BBB. Here we describe a protocol to obtain a BBTB mimic by culturing endothelial cells in contact with astrocytes at specific cell densities on inserts. This BBTB mimic can be used, for instance, for the quantification and confocal imaging of the nanoparticle passage through the endothelial and astrocytic barriers, in addition to the evaluation of the tumor cell targeting within the same assay. Moreover, we show that the obtained data can be used to predict the behavior of nanoparticles in preclinical animal models. In a broader perspective, this in vitro model could be adapted to other neurodegenerative diseases for the determination of the passage of new therapeutic molecules through the BBB and/or be supplemented with brain organoids to directly evaluate the efficacy of drugs.

Drug targeting to central nervous system tumors is a major challenge. Here we describe a protocol to produce an in vitro mimic of the blood-brain tumor-barrier using murine and/or human cells and discuss their relevance for the predictability of central nervous system tumor targeting in vivo.

Highly selective by nature, the blood-brain barrier (BBB) is essential for the brain homeostasis in physiological conditions. However, in the context of ...

Detection and Monitoring of Tumor Associated Circulating DNA in Patient Biofluids

Complications associated with upfront and repeat surgical tissue sampling present the need for minimally invasive platforms capable of molecular sub-classification and temporal monitoring of tumor response to therapy. Here, we describe our dPCR-based method for the detection of tumor somatic mutations in cell free DNA (cfDNA), readily available in&#160;patient biofluids. Although limited in the number of mutations that can be tested for in each assay, this method provides a high level of sensitivity and specificity. Monitoring of mutation abundance, as calculated by MAF, allows for the evaluation of tumor response to therapy, thereby providing a much-needed supplement to radiographic imaging.

Here, we present a protocol to detect tumor somatic mutations in circulating DNA present in patient biological fluids (biofluids). Our droplet digital polymerase chain reaction (dPCR)-based method enables quantification of the tumor mutation allelic frequency (MAF), facilitating a minimally invasive complement to diagnosis and temporal monitoring of tumor response.

Complications associated with upfront and repeat surgical tissue sampling present the need for minimally invasive platforms capable of molecular ...

Characterize Disease-related Mutants of RAF Family Kinases by Using a Set of Practical and Feasible Methods

The rapidly accelerated fibrosarcoma (RAF) family kinases play a central role in cell biology and their dysfunction leads to cancers and developmental disorders. A characterization of disease-related RAF mutants will help us select appropriate therapeutic strategies for treating these diseases. Recent studies have shown that RAF family kinases have both catalytic and allosteric activities, which are tightly regulated by dimerization. Here, we constructed a set of practical and feasible methods to determine the catalytic and allosteric activities and the relative dimer affinity/stability of RAF family kinases and their mutants. Firstly, we amended the classical in vitro kinase assay by reducing the detergent concentration in buffers, utilizing a gentle quick wash procedure, and employing a glutathione S-transferase (GST) fusion to prevent RAF dimers from dissociating during purification. This enables us to measure the catalytic activity of constitutively active RAF mutants appropriately. Secondly, we developed a novel RAF co-activation assay to evaluate the allosteric activity of kinase-dead RAF mutants by using N-terminal truncated RAF proteins, eliminating the requirement of active Ras in current protocols and thereby achieving a higher sensitivity. Lastly, we generated a unique complementary split luciferase assay to quantitatively measure the relative dimer affinity/stability of various RAF mutants, which is more reliable and sensitive compared to the traditional co-immunoprecipitation assay. In summary, these methods have the following advantages: (1) user-friendly; (2) able to carry out effectively without advanced equipment; (3) cost-effective; (4) highly sensitive and reproducible.

In this article, we presented a set of practical and feasible methods for characterizing disease-related mutants of RAF family kinases, which include in vitro kinase assay, RAF co-activation assay, and complementary split luciferase assay.

The rapidly accelerated fibrosarcoma (RAF) family kinases play a central role in cell biology and their dysfunction leads to cancers and developmental ...

Identification of Transcription Factor Regulators using Medium-Throughput Screening of Arrayed Libraries and a Dual-Luciferase-Based Reporter

Transcription factors can alter the expression of numerous target genes that influence a variety of downstream processes making them good targets for anti-cancer therapies. However, directly targeting transcription factors is often difficult and can cause adverse side effects if the transcription factor is necessary in one or more adult tissues. Identifying upstream regulators that aberrantly activate transcription factors in cancer cells offers a more feasible alternative, particularly if these proteins are easy to drug. Here, we describe a protocol that can be used to combine arrayed medium-scale lentiviral libraries and a dual-luciferase-based transcriptional reporter assay to identify novel regulators of transcription factors in cancer cells. Our approach offers a quick, easy, and inexpensive way to test hundreds of genes in a single experiment. To demonstrate the use of this approach, we performed a screen of an arrayed lentiviral RNAi library containing several regulators of Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), two transcriptional co-activators that are the downstream effectors of the Hippo pathway. However, this approach could be modified to screen for regulators of virtually any transcription factor or co-factor and could also be used to screen CRISPR/CAS9, cDNA, or ORF libraries.

To identify novel regulators of transcription factors, we developed an approach to screen arrayed lentiviral or retroviral RNAi libraries using a dual-luciferase-based transcriptional reporter assay. This approach offers a quick and relatively inexpensive way to screen hundreds of candidates in a single experiment.

Transcription factors can alter the expression of numerous target genes that influence a variety of downstream processes making them good targets for ...

Impedance-based Real-time Measurement of Cancer Cell Migration and Invasion

Cancer arises due to uncontrolled proliferation of cells initiated by genetic instability, mutations, and environmental and other stress factors. These acquired abnormalities in complex, multilayered molecular signaling networks induce aberrant cell proliferation and survival, extracellular matrix degradation, and metastasis to distant organs. Approximately 90% of cancer-related deaths are estimated to be caused by the direct or indirect effects of metastatic dissemination. Therefore, it is important to establish a highly reliable, comprehensive system to characterize cancer cell behaviors upon genetic and environmental manipulations. Such a system can give a clear understanding of the molecular regulation of cancer metastasis and the opportunity for successful development of stratified, precise therapeutic strategies. Hence, accurate determination of cancer cell behaviors such as migration and invasion with gain or loss of function of gene(s) allows assessment of the aggressive nature of cancer cells. The real-time measurement system based on cell impedance enables researchers to continually acquire data during a whole experiment and instantly compare and quantify the results under various experimental conditions. Unlike conventional methods, this method does not require fixation, staining, and sample processing to analyze cells that migrate or invade. This method paper emphasizes detailed procedures for real-time determination of migration and invasion of glioblastoma cancer cells.

Cancer is a lethal disease due to its ability to metastasize to different organs. Determining the ability of cancer cells to migrate and invade under various treatment conditions is crucial to assessing therapeutic strategies. This protocol presents a method to assess the real-time metastatic abilities of a glioblastoma cancer cell line.&#160;

Cancer arises due to uncontrolled proliferation of cells initiated by genetic instability, mutations, and environmental and other stress factors. These ...