Name: evaporation-reducing culture condition increases the reproducibility of multicellular spheroid formation in microtiter plates
Uploaded: 2017-03-07T14:00:00
Description: Watch this Scientific Journal Video about Evaporation-reducing Culture Condition Increases the Reproducibility of Multicellular Spheroid Formation in Microtiter Plates at JoVE.com

This work was supported by grants from the Czech Ministry of Education, Youth, and Sports (LO1304) and the Technological Agency of the Czech Republic (TE01020028). The authors would like to thank Dr. Lakshman Varanasi for taking the still images of environmental lids.

1. Preparation of Agarose-coated Plates
<ol>
	<li>Weigh 0.75 g of low-melting point agarose and add it to 100 mL of McCoy&#39;s 5A medium (with or without phenol red) without serum. Heat the solution in a microwave and swirl every 1-2 min to completely dissolve the agarose. Autoclave the solution to sterilize it.</li>
	<li>Cool the autoclaved agarose to about 70 &#176;C and filter it through a 500 mL, 0.22 &#181;m filter top by vacuum filtration in a laminar flow box. Aliquot the 0.75% filtered agarose solution (FAS) i...

<ol>
	<li>Kimlin, L. C., Casagrande, G., Virador, V. M. <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+three-dimensional+(3D)+models+in+cancer+research:+An+update.">In vitro three-dimensional (3D) models in cancer research: An update.</a> Mol Carcinog. 52 (3), 167-182 (2013).</li><li>Das, V., Bruzzese, F., Kone&#269;n&#253;, P., Iannelli, F., Budillon, A., Hajd&#250;ch, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathophysiologically+relevant+in+vitro+tumor+models+for+drug+screening.">Pathophysiologically relevant in vitro tumor models for drug screening.</a> Drug Discov. Today. 20 (7), 848-855 (2015).</li><li>Weigelt, B., Ghajar, C. M., Bissell, M. 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+need+for+complex+3D+culture+models+to+unravel+novel+pathways+and+identify+accurate+biomarkers+in+breast+cancer.">The need for complex 3D culture models to unravel novel pathways and identify accurate biomarkers in breast cancer.</a> Adv. Drug Deliv. Rev. , 69-70 (2014).</li><li>Fischbach, C., Kong, H. J., Hsiong, S. X., Evangelista, M. B., Yuen, W., Mooney, D. 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Cell Res. 323 (1), 131-143 (2014).</li><li>Li, Q., 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=3D+Models+of+Epithelial-Mesenchymal+Transition+in+Breast+Cancer+Metastasis:+High-Throughput+Screening+Assay+Development,+Validation,+and+Pilot+Screen.">3D Models of Epithelial-Mesenchymal Transition in Breast Cancer Metastasis: High-Throughput Screening Assay Development, Validation, and Pilot Screen.</a> J. Biomol. Screen. 16 (2), 141-154 (2011).</li><li>Das, V., F&#252;rst, T., Gursk&#225;, S., D&#382;ub&#225;k, P., Hajd&#250;ch, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reproducibility+of+Uniform+Spheroid+Formation+in+384-Well+Plates:+The+Effect+of+Medium+Evaporation.">Reproducibility of Uniform Spheroid Formation in 384-Well Plates: The Effect of Medium Evaporation.</a> J. Biomol. Screen. , (2016).</li><li>Celli, J. P., 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=An+imaging-based+platform+for+high-content,+quantitative+evaluation+of+therapeutic+response+in+3D+tumour+models.">An imaging-based platform for high-content, quantitative evaluation of therapeutic response in 3D tumour models.</a> Sci. Rep. 17 (4), 3751 (2014).</li><li>Solomon, M. A., Lemera, J., D'Souza, G. G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+an+in+vitro+tumor+spheroid+culture+model+amenable+to+high-throughput+testing+of+potential+anticancer+nanotherapeutics.">Development of an in vitro tumor spheroid culture model amenable to high-throughput testing of potential anticancer nanotherapeutics.</a> J. Liposome Res. 26 (3), 246-260 (2016).</li><li>Costa, E. C., Gaspar, V. M., Coutinho, P., Correia, I. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+liquid+overlay+technique+to+formulate+heterogenic+3D+co-cultures+models.">Optimization of liquid overlay technique to formulate heterogenic 3D co-cultures models.</a> Biotechnol. Bioeng. 111 (8), 1672-1685 (2014).</li><li>Walzl, 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=A+Simple+and+Cost+Efficient+Method+to+Avoid+Unequal+Evaporation+in+Cellular+Screening+Assays,+Which+Restores+Cellular+Metabolic+Activity.">A Simple and Cost Efficient Method to Avoid Unequal Evaporation in Cellular Screening Assays, Which Restores Cellular Metabolic Activity.</a> Int. J. Appl. Sci. Technol. 2 (6), 17-25 (2012).</li><li>Berthier, E., Warrick, J., Yu, H., Beebe, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Managing+evaporation+for+more+robust+microscale+assays.+Part+1.+Volume+loss+in+high+throughput+assays.">Managing evaporation for more robust microscale assays. Part 1. Volume loss in high throughput assays.</a> Lab Chip. 8 (6), 852-859 (2008).</li><li>Zanoni, 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=3D+tumor+spheroid+models+for+in+vitro+therapeutic+screening:+a+systematic+approach+to+enhance+the+biological+relevance+of+data+obtained.">3D tumor spheroid models for in vitro therapeutic screening: a systematic approach to enhance the biological relevance of data obtained.</a> Sci. Rep. 6, 19103 (2016).</li><li>Zimmermann, H. F., John, G. T., Trauthwein, H., Dingerdissen, U., Huthmacher, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+Evaluation+of+Oxygen+and+Water+Permeation+through+Microplate+Sealing+Tapes.">Rapid Evaluation of Oxygen and Water Permeation through Microplate Sealing Tapes.</a> Biotechnol. Prog. 19 (3), 1061-1063 (2003).</li><li>Sirenko, O., Mitlo, T., Hesley, J., Luke, S., Owens, W., Cromwell, E. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-Content+Assays+for+Characterizing+the+Viability+and+Morphology+of+3D+Cancer+Spheroid+Cultures.">High-Content Assays for Characterizing the Viability and Morphology of 3D Cancer Spheroid Cultures.</a> Assay Drug Dev. Technol. 13 (7), 402-414 (2015).</li><li>Chen, W., Wong, C., Vosburgh, E., Levine, A. J., Foran, D. J., Xu, E. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-throughput+Image+Analysis+of+Tumor+Spheroids:+A+User-friendly+Software+Application+to+Measure+the+Size+of+Spheroids+Automatically.">High-throughput Image Analysis of Tumor Spheroids: A User-friendly Software Application to Measure the Size of Spheroids Automatically.</a> J. Vis. Exp. (89), e51639 (2014).</li></ol>

Coating 384-Well TC Plates with Filtered Agarose
The standard practice in LOT is to use a 1-1.5% low-melting point agarose to coat the plates, which requires the agarose and/or dispensing unit to be kept heated to prevent the gelling of the agarose6. The gelling of the agarose is of potential concern while preparing multiple plates using liquid dispensing cassettes with small tubing apertures ranging between 0.2 and 0.4 mm in diameter. To overcome the potential issue of cl...

Cancer cells in tumors are physiologically arranged in a complex, 3-dimensional (3D) structure surrounded by extracellular matrix and interacting cells. As nearly all cells in tissues reside in a 3D environment, the need for more physiologically relevant in vitro tumor models that mimic tumor traits has resulted in the development of several 3D culture techniques1,2,3. These models are now becoming fundamental research tools for studying the role of the tumor microenvironment on metastasis and cell response to therapeutics in 3D2. Moreover, compared to 2-dimensional (2D) cell cultures4, 3D models allow for a better understanding of tumor-stroma interactions, which affect cell signaling pathways.
Multicellular tumor spheroids (MCTSes) of cancer cell lines are frequently used in 3D cell culture models due to their relative closeness to in vivo tumors. Out of the several techniques in use, the liquid-overlay technique (LOT) of MCTS generation on agarose-coated plates has gained significant interest for lead optimization and target validation5,6,7,8,9,10,11. This is evident from the recent studies that were successfully able to run pilot screens of compound libraries in MCTS cultures using LOT6,7. However, well-to-well variability in MCTS morphology and growth due to the evaporation-induced uneven loss of medium are common hurdles that accompany the LOT using microtiter plates (MPs). Consequently, the formation of non-uniform MCTSes compromises the significance and relevance of data from pharmacological assays8,12,13. In addition to the reproducibility issues, another practical problem that affects LOT-based high-throughput assays is the coating of the MPs with agarose when using automatic liquid dispensing units. Although the dispensing unit can be kept heated to prevent the gelling of agarose, the clogging of the dispensing cassette and tubing is a potential concern for robotic systems6.
To overcome some of these challenges, we have recently devised a few modifications in the LOT for MCTS culture8. These modifications are mainly based on possible ways to prevent uneven medium loss from the MPs using instruments that are commonly found in high-throughput screening laboratories. A detailed procedure of the modified LOT for the generation of uniformly sized and reproducible MCTSes across 384-well plates (WPs) is presented here. The manuscript also presents a semi-automated routine for the evaluation of MCTS size, particularly in partially disintegrated, drug-treated MCTSes that do not have a clearly defined boundary for the measurement of cross-sectional area.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Agarose</td>
			<td>Sigma-Aldrich</td>
			<td>A9414</td>
			<td>Low-melting</td>
		</tr>
		<tr>
			<td>McCOY&#39;s 5A Medium</td>
			<td>Sigma-Aldrich</td>
			<td>M8403</td>
			<td></td>
		</tr>
		<tr>
			<td>&#8220;rapid&#8221; Filtermax filter</td>
			<td>TPP</td>
			<td>99505</td>
			<td>0.22 &#956;m, 500 mL</td>
		</tr>
		<tr>
			<td>Multidrop&#8482; Combi Reagent Dispenser&#160;</td>
			<td>Thermo Fisher Scientific</td>
			<td>5840300</td>
			<td></td>
		</tr>
		<tr>
			<td>Small Tube Dispensing cassette&#160;</td>
			<td>Thermo Fisher Scientific</td>
			<td>24073295</td>
			<td>Metal tip&#160;</td>
		</tr>
		<tr>
			<td>384-well TC plate&#160;</td>
			<td>PerkinElmer</td>
			<td>6057308</td>
			<td>Plate type- CellCarrier</td>
		</tr>
		<tr>
			<td>Standard Tube Dispensing Cassette</td>
			<td>Thermo Fisher Scientific</td>
			<td>24072670</td>
			<td></td>
		</tr>
		<tr>
			<td>MicroClime Environmental Lid</td>
			<td>Labcyte</td>
			<td>LLS-0310</td>
			<td></td>
		</tr>
		<tr>
			<td>DMSO</td>
			<td>Sigma</td>
			<td>D4540</td>
			<td></td>
		</tr>
		<tr>
			<td>Rotary Incubator (SteriStore )</td>
			<td>HighRes Biosolutions</td>
			<td>23641</td>
			<td>Serial No.: D00384</td>
		</tr>
		<tr>
			<td>Microplate Washer Dispenser&#160;</td>
			<td>BioTek</td>
			<td>Unspecified</td>
			<td>Model: EL406&#160;</td>
		</tr>
		<tr>
			<td>High-Content Imaging System (CellVoyager )</td>
			<td>Yokogawa Electric Corporation</td>
			<td>Unspecified</td>
			<td>Model: CV7000</td>
		</tr>
		<tr>
			<td>Orange G</td>
			<td>New England Biolabs</td>
			<td>B7022S</td>
			<td></td>
		</tr>
		<tr>
			<td>TrypLE&#8482; Express recombinant cell dissociation reagent</td>
			<td>Thermo Fisher Scientific</td>
			<td>12604021</td>
			<td>Phenol red free</td>
		</tr>
	</tbody>
</table>

evaporation-reducing culture condition increases the reproducibility of multicellular spheroid formation in microtiter plates

Tumor models that closely imitate in vivo conditions are becoming increasingly popular in drug discovery and development for the screening of potential anti-cancer drugs. Multicellular tumor spheroids (MCTSes) effectively mimic the physiological conditions of solid tumors, making them excellent in vitro models for lead optimization and target validation. Out of the various techniques available for MCTS culture, the liquid-overlay method on agarose is one of the most inexpensive methods for MCTS generation. However, the reliable transfer of MCTS cultures using liquid-overlay for high-throughput screening may be compromised by a number of limitations, including the coating of microtiter plates (MPs) with agarose and the irreproducibility of uniform MCTS formation across wells. MPs are significantly prone to edge effects that result from excessive evaporation of medium from the exterior of the plate, preventing the use of the entire plate for drug tests. This manuscript provides detailed technical improvements to the liquid-overlay technique to increase the scalability and reproducibility of uniform MCTS formation. Additionally, details on a simple, semi-automatic, and universally applicable software tool for the evaluation of MCTS features after drug treatment is presented.

The uneven loss of medium, particularly from peripheral wells, is a frequently encountered issue in MPs with small culture volumes. Substantially improved culture conditions, such as incubators with well-controlled temperature/humidification systems and evaporation-reducing MPs and plate lids, reduce the significant loss of medium across wells8. To measure the relative evaporation, equal volumes of Orange G (OG) were added to each well, and the change in OG absorba...

Watch this Scientific Journal Video about Evaporation-reducing Culture Condition Increases the Reproducibility of Multicellular Spheroid Formation in Microtiter Plates at JoVE.com

Evaporation-reducing Culture Condition Increases the Reproducibility of Multicellular Spheroid Formation in Microtiter Plates

The uneven loss of medium from microtiter plates affects the reproducibility of uniform multicellular tumor spheroid formation. Improving culture conditions to reduce significant medium loss will improve the reproducibility of spheroid formation and the results of spheroid-based assays using the liquid-overlay technique.

Tumor models that closely imitate in vivo conditions are becoming increasingly popular in drug discovery and development for the screening of potential ...

The overall goal of this procedure is to improve the scalability and reproducibility of uniform spheroid formation using a liquid overlay technique in 384 well plates. The main advantage of this technique is that it reduces excessive medium re-operation from multiple plates, and thereby improving the reproducibility of spheroid formation. We have developed and validated the method of culturing 3D spheroids for arthropod screening tests in our laboratory and our study was to evaluate what is the edge effect in the plates of the multicellular cultures.Today I will demonstrate the procedure together with Sona, a poster from the laboratory. Begin this procedure by weighting out zero point seven five grams of low melting point agarose and add it to 100 milliliters of mccoy's 5a medium with or without phenol red and without serum. Heat the solution in a microwave and swirl it every one to two minutes to completely dissolve the agarose.Then autoclave the solution to sterilize it. After allowing the autoclaved agarose to cool to about 70 degrees Celsius, filter it through a 500 milliliter zero point two two micrometer bottle top filter in a laminar flow box. Next, if the entire solution will not be used at once, aliquot it.Store this ready to use agarose solution aseptically in a cold room or four degree Celsius fridge for up to four weeks. Working in a flow box, install a plastic or metal-tipped dispensing cassette in a combi reagent dispenser. Place the tubing weight into a vessel of 70 percent ethanol and then prime the cassette.Then, move the tubing weight into a vessel of PBS and prime it again. Next, heat a stored aliquot of filtered agarose solution in the microwave to melt it. Prime the dispensing cassette with agarose solution and then start the protocol to coat 384 well tissue culture treated micro plates with 15 microliters of filtered agarose solution.Allow the agarose in the plate to cool for 15 to 20 minutes before either seeding the cells as described in the next section of the video, or storing them at four degrees Celsius and away from direct light. Finally, to clean the dispensing cassette, place the tubing weight in 70 to 80 degree celsius sterile water and press the prime button on the dispenser. This will remove any remaining agarose in the cassette tips and the tubes.The following cell seeding process should be performed under sterile conditions and in a laminar flow box. Begin by removing the required number of agarose coated 384 well tissue culture treated microplates from cold storage and allowing them to equilibrate to room temperature for 15 minutes. In the meantime, prepare the combi reagent dispenser for cell seeing by priming a standard tube dispensing cassette with 70 percent ethanol and sterile PBS.Next, using the manual setting buttons on the dispenser, adjust the seeing volume to the required microliter and the dispensing speed to medium. Use recombinant cell dissociation enzyme to remove adherent human colorectal carcinoma HCT116 cells from a tissue culture flask. In a sterile beaker, make a cell suspension stock with cells at a density of 2.5 time 10 to the fourth cells per milliliter per well in 50 microliters of complete growth medium.If more than one 384 well plate will be seeded, use a magnetic stirrer to prevent them from settling to the bottom of the beaker. Using a dispenser, add the 25 hundred cells to each well of a 384 well plate. Allow the plates to rest for 30 minutes at room temperature.Meanwhile, take an evaporation reducing environmental microplate lid and using a five milliliter pipette, dispense four milliliters of five percent dimethylsulfoxide into the left side trough, sweeping slowly up and down. Repeat this process with the right side trough. Ensure that the liquid added to the side troughs does not merge at the center of the lid and leave a gap for gas exchange.If too much liquid is added, it will seep into the exterior of the lid and subsequently enter the outer well of the 384 tissue culture plate. After 30 minutes has passed, examine the cells under a microscope. Resting of the plates for 30 minutes allows the cells to settle down completely in the well bottom and close to each other, which is important for the formation of single spheroids per well.Centrifuge the seeded plates for 15 minutes at four times G.After the spin, fill the liquid reservoir of the 384 tissue culture plate with sterile water and replace the regular plate lids with the liquid filled environmental lids. Place the plates in a 37 degree celsius rotary incubator with 95 percent humidity, five percent CO2, and 20 percent oxygen and allow the cells to aggregate into multicellular tumor spheroids or MCTS's for four days. Avoid opening the incubator door for too long in the subsequent days so that the humidity level does not drop abruptly.On day four following NCTS formation, use an automated microplate washer dispenser to add 30 microliters of prewarmed medium to each well. Place the MCTSs back in the incubator and allow the MCTSs to grow until they attain the desired size for experimentation. Every three days, to replace the medium, empirically adjust the Z height of the washer manifold and set the dispensing speed and the speed at which the wash manifold travels down into the wells at the lowest rate to minimize turbulence in the wells.Aspirate 30 microliters of medium per well and replace it with 30 microliters of fresh, pre-warmed medium. Then return the cells to the incubator. Image the MCTSs in a high content automated imaging system using a four X air objecting with a numerical aperture of 16.Using the imaging software, set the exposure time to 11 milliseconds and the binning to four by four. Adjust the number and spacing of the z-stacks and the pixel binning as desired for the experiment to capture an entire MCTS in each well. Process the 2D images stepwise to measure the MCTS area, major and minor axis, perimeter, and solidity.Please see the accompanying m-code and text read me files for specific instructions. To determine the potential applicability of the routine, seven day old MCTSs were treated with different concentrations of the anti-cancer drugs, Paclitaxel, PTX, Vincristine, VCR, Oxalyplatin, OXA, Doxyrubicin, DOX, and five flurouracil, 5-FU, at three different concentrations for four days. Images of the MCTSs are shown here.These images were analyzed to determine the area, major and minor axes, perimeter, and solidity of drug treated MCTSs compared to controls, CTLs. The major and minor axes were used to calculate the geometrical volume. There was a concentration dependent decrease in MCTS area and volume after drug treatment.Although point zero one micrograms per milliliter of Vincrystine and zero point four micrograms per milliliter Doxyrubicin and five Fluorouracil resulted in an increase in MCTS area, the volume was significantly increased only following point zero zero one micrograms per milliliters Vincrystine. MCTS perimeter was significantly different only at the highest concentrations of Packlitaxel, Doxyrubicin, and Five Fleurouracil which completely affected the MCTS size. Treament with Packlitaxel and Vincrystine at zero point two five micrograms per milliliter and zero point zero six micrograms per milliliter and Doxyrubicin and Five Fleurouracil at 100 micrograms per milliliter, resulted in a significant decrease in the solidity, indicating a complete to partial disintegration of the MCTSs.Taken together, these data demonstrate the utility of this method in investigating potential anti cancer drugs. Once mastered, this technique can be done in two hours if performed properly. When attempting this procedure, it is important to note that not all cell lines are suitable for a particular 3D culture method and different cell lines form spheroids that show differences in spheroid shapes, size, histology, and growth kinetics.The stimulatory routine that we have developed allows effective evaluation of spheroid size, particularly in partially disintegrated drug treated spheroid that do not have a clearly defined boundary for the measurement of cross sectional area. After watching this video, you should have a good understanding of the fact that modification present here does not require any additional equipment or consumables and can be routinely implemented in your arthropod screening lab.

evaporation-reducing-culture-condition-increases-reproducibility

Research

JoVE Journal

Cancer Research

Utilizing Functional Genomics Screening to Identify Potentially Novel Drug Targets in Cancer Cell Spheroid Cultures

The identification of functional driver events in cancer is central to furthering our understanding of cancer biology and indispensable for the discovery of the next generation of novel drug targets. It is becoming apparent that more complex models of cancer are required to fully appreciate the contributing factors that drive tumorigenesis in vivo and increase the efficacy of novel therapies that make the transition from pre-clinical models to clinical trials.
Here we present a methodology for generating uniform and reproducible tumor spheroids that can be subjected to siRNA functional screening. These spheroids display many characteristics that are found in solid tumors that are not present in traditional two-dimension culture. We show that several commonly used breast cancer cell lines are amenable to this protocol. Furthermore, we provide proof-of-principle data utilizing the breast cancer cell line BT474, confirming their dependency on amplification of the epidermal growth factor receptor HER2 and mutation of phosphatidylinositol-4,5-biphosphate 3-kinase (PIK3CA) when grown as tumor spheroids. Finally, we are able to further investigate and confirm the spatial impact of these dependencies using immunohistochemistry.

Identifying novel drug targets that transition from pre-clinical testing to human trials is a scientific priority. To that end, here we describe a functional genomics approach for examining the impact of gene depletion on cancer cell line spheroids, which more appropriately model human cancers in vivo.

The identification of functional driver events in cancer is central to furthering our understanding of cancer biology and indispensable for the discovery ...

A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s

N-nitrosamines are a well-established group of environmental carcinogens, which require cytochrome P450 oxidation to exhibit activity. The accepted mechanism of metabolic activation involves formation of &#945;-hydroxynitrosamines that spontaneously decompose to DNA alkylating agents. Accumulation of DNA damage and the resulting mutations can ultimately lead to cancer. New evidence indicates that &#945;-hydroxynitrosamines can be further oxidized to nitrosamides processively by cytochrome P450s. Because nitrosamides are generally more stable than &#945;-hydroxynitrosamines and can also alkylate DNA, nitrosamides may play a role in carcinogenesis. In this report, we describe a general protocol for evaluating nitrosamide production from in vitro cytochrome P450-catalyzed metabolism of nitrosamines. This protocol utilizes a general approach to the synthesis of the relevant nitrosamides and an in vitro cytochrome P450 metabolism assay using liquid chromatography-nanospray ionization-high resolution tandem mass spectrometry for detection. This method detected N&#8242;-nitrosonorcotinine as a minor metabolite of N&#8242;-nitrosonornicotine in the example study. The method has high sensitivity and selectively due to accurate mass detection. Application of this method to a wide variety of nitrosamine-cytochrome P450 systems will help determine the generality of this transformation. Because cytochrome P450s are polymorphic and vary in activity, a better understanding of nitrosamide formation could aid in individual cancer risk assessment.

A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s

&#945;-hydroxylation of carcinogenic nitrosamines by cytochrome P450s is the accepted metabolic pathway that produces DNA-damaging intermediates, which cause mutations. However, new data indicates further oxidation to nitrosamides can occur. We describe a general method for detecting nitrosamides produced from in vitro cytochrome P450-catalyzed metabolism of nitrosamines.

N-nitrosamines are a well-established group of environmental carcinogens, which require cytochrome P450 oxidation to exhibit activity. The accepted ...

Therapy Testing in a Spheroid-based 3D Cell Culture Model for Head and Neck Squamous Cell Carcinoma

Current treatment options for advanced and recurrent head and neck squamous cell carcinoma (HNSCC) enclose radiation and chemo-radiation approaches with or without surgery. While platinum-based chemotherapy regimens currently represent the gold standard in terms of efficacy and are given in the vast majority of cases, new chemotherapy regimens, namely immunotherapy are emerging. However, the response rates and therapy resistance mechanisms for either chemo regimen are hard to predict and remain insufficiently understood. Broad variations of chemo and radiation resistance mechanisms are known to date. This study describes the development of a standardized, high-throughput in vitro assay to assess HNSCC cell line&#39;s response to various therapy regimens, and hopefully on primary cells from individual patients as a future tool for personalized tumor therapy. The assay is designed to being integrated into the quality-controlled standard algorithm for HNSCC patients at our tertiary care center; however, this will be subject of future studies. Technical feasibility looks promising for primary cells from tumor biopsies from actual patients. Specimens are then transferred into the laboratory. Biopsies are mechanically separated followed by enzymatic digestion. Cells are then cultured in ultra-low adhesion cell culture vials that promote the reproducible, standardized and spontaneous formation of three-dimensional, spheroid-shaped cell conglomerates. Spheroids are then ready to be exposed to chemo-radiation protocols and immunotherapy protocols as needed. The final cell viability and spheroid size are indicators of therapy susceptibility and therefore could be drawn into consideration in future to assess the patients&#39; likely therapy response. This model could be a valuable, cost-efficient tool towards personalized therapy for head and neck cancer.

We describe the evolution of a spheroid-based, three-dimensional in vitro model that enables us to test the current standard of experimental therapy regimens for head and neck squamous cell carcinoma on cell lines, aiming at evaluating therapy susceptibility and resistance on primary cells from human specimens in the future.

Current treatment options for advanced and recurrent head and neck squamous cell carcinoma (HNSCC) enclose radiation and chemo-radiation approaches with ...

A Comprehensive Procedure to Evaluate the In Vitro Performance of the Putative Hemangioblastoma Neovascularization Using the Spheroid Sprouting Assay

The inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene plays a crucial role in the development of hemangioblastomas (HBs) within the human central nervous system (CNS). However, both the cytological origin and the evolutionary process of HBs (including neovascularization) remain controversial, and anti-angiogenesis for VHL-HBs, based on classic HB angiogenesis, have produced disappointing results in clinical trials. One major obstacle to the successful clinical translation of anti-vascular treatment is the lack of a thorough understanding of neovascularization in this vascular tumor. In this article, we present a comprehensive procedure to evaluate in vitro whether classic tumor angiogenesis exists in HBs, as well as its role in HBs. With this procedure, researchers can accurately understand the complexity of HB neovascularization and identify the function of this common form of angiogenesis in HBs. These protocols can be used to evaluate the most promising anti-vascular therapy for tumors, which has high translational potential either for tumors treatment or for aiding in the optimization of the anti-angiogenic treatment for HBs in future translations. The results highlight the complexity of HB neovascularization and suggest that this common form angiogenesis is only a complementary mechanism in HB neovascularization.

A Comprehensive Procedure to Evaluate the In Vitro Performance of the Putative Hemangioblastoma Neovascularization Using the Spheroid Sprouting Assay

This paper presents a comprehensive procedure to evaluate in vitro whether classic tumor angiogenesis exists in hemangioblastomas (HBs) and its role in HBs. The results highlight the complexity of HB-neovascularization and suggest that this common form of angiogenesis is only a complementary mechanism in the HB-neovascularization.

The inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene plays a crucial role in the development of hemangioblastomas (HBs) within the human ...

Potentiation of Anticancer Antibody Efficacy by Antineoplastic Drugs: Detection of Antibody-drug Synergism Using the Combination Index Equation

Potentiation of hostile monoclonal antibodies (mAb) by chemotherapeutic agents constitutes a valuable strategy for designing effective and safer therapy against cancer. Here we provide a protocol to identify a rational combination at the preclinical step. First, we describe a cell-based assay to assess the synergism between anticancer mAb and cytotoxic drugs, that uses the combination index equation of Chou and Talalay1. This includes the measurement of tumor cell drug- and antibody-sensitivity using an MTT assay, followed by an automated computer analysis to calculate the combination index (CI) values. CI values of &lt;1 indicate synergism between tested mAbs and cytotoxic agents1. To corroborate the in vitro findings in vivo, we further describe a method to assess the combination regimen efficacy in a xenograft tumor model. In this model, the combined regimen significantly delays tumor growth, which results in a significant extended survival in comparison to single-agent controls. Importantly, the in vivo experimentation reveals that the combination regimen is well tolerated. This protocol allows the effective evaluation of anticancer drug combinations in preclinical models and the identification of rational combination to evaluate in clinical trials.

This protocol describes how to assess synergism between an anticancer antibody and antineoplastic drugs in preclinical models by using the combination index equation of Chou and Talalay.

Potentiation of hostile monoclonal antibodies (mAb) by chemotherapeutic agents constitutes a valuable strategy for designing effective and safer therapy ...

Identification, Histological Characterization, and Dissection of Mouse Prostate Lobes for In Vitro 3D Spheroid Culture Models

Genetically engineered mouse models (GEMMs) serve as effective pre-clinical models for investigating most types of human cancers, including prostate cancer (PCa). Understanding the anatomy and histology of the mouse prostate is important for the efficient use and proper characterization of such animal models. The mouse prostate has four distinct pairs of lobes, each with their own characteristics. This article demonstrates the proper method of dissection and identification of mouse prostate lobes for disease analysis. Post-dissection, the prostate cells can be further cultured in vitro for mechanistic understanding. Since mouse prostate primary cells tend to lose their normal characteristics when cultured in vitro, we outline here a method for isolating the cells and growing them as 3D spheroid cultures, which is effective for preserving the physiological characteristics of the cells. These 3D cultures can be used for analyzing cell morphology and behavior in near-physiological conditions, investigating altered levels and localizations of key proteins and pathways involved in the development and progression of a disease, and looking at responses to drug treatments.

Genetically engineered mice are useful models for investigating prostate cancer mechanisms. Here we present a protocol to identify and dissect prostate lobes from a mouse urogenital system, differentiate them based on histology, and isolate and culture the primary prostate cells in vitro as spheroids for downstream analyses.

Genetically engineered mouse models (GEMMs) serve as effective pre-clinical models for investigating most types of human cancers, including prostate ...

A Spheroid Killing Assay by CAR T Cells

Immunotherapy has become a field of growing interest in the fight against cancer otherwise untreatable. Among all immunotherapeutic methods, chimeric antigen receptor (CAR) redirected T cells obtained the most spectacular results, in particular with pediatric B-acute lymphoblastic leukemia (B-ALL). Classical validation methods of CAR T cells rely on the use of specificity and functionality assays of the CAR T cells against target cells in suspension and in xenograft models. Unfortunately, observations made in vitro are often decoupled from results obtained in vivo and a lot of effort and animals could be spared by adding another step: the use of 3D culture. The production of spheroids out of potential target cells that mimic the 3D structure of the tumor cells when they are engrafted into the animal model represents an ideal alternative. Here, we report an affordable, reliable and easy method to produce spheroids from a transduced colorectal cell line as a validation tool for adoptive cell therapy (exemplified here by CD19 CAR T cells). This method is coupled with an advanced live imaging system that can follow spheroid growth, effector cells cytotoxicity and tumor cell apoptosis.

This protocol is designed to assess immunotherapeutic redirected T-cell (CAR T-cell) cytotoxicity against 3D structured cancerous cells (spheroids) in real time.

Immunotherapy has become a field of growing interest in the fight against cancer otherwise untreatable. Among all immunotherapeutic methods, chimeric ...

Fully Human Tumor-based Matrix in Three-dimensional Spheroid Invasion Assay

Two-dimensional cell culture-based assays are commonly used in in vitro cancer research. However, they lack several basic elements that form the tumor microenvironment. To obtain more reliable in vitro results, several three-dimensional (3D) cell culture assays have been introduced. These assays allow cancer cells to interact with the extracellular matrix. This interaction affects cell behavior, such as proliferation and invasion, as well as cell morphology. Additionally, this interaction could induce or suppress the expression of several pro- and anti-tumorigenic molecules. Spheroid invasion assay was developed to provide a suitable 3D in vitro method to study cancer cell invasion. Currently, animal-derived matrices, such as mouse sarcoma-derived matrix (MSDM) and rat tail type I collagen, are mainly used in the spheroid invasion assays. Taking into consideration the differences between the human tumor microenvironment and animal-derived matrices, a human myoma-derived matrix (HMDM) was developed from benign uterus leiomyoma tissue. It has been shown that HMDM induces migration and invasion of carcinoma cells better than MSDM. This protocol provided a simple, reproducible, and reliable 3D human tumor-based spheroid invasion assay using the HMDM/fibrin matrix. It also includes detailed instructions on imaging and analysis. The spheroids grow in a U-shaped ultra-low attachment plate within the HMDM/fibrin matrix and invade through it. The invasion is daily imaged, measured, and analyzed using ilastik and Fiji ImageJ software. The assay platform was demonstrated using human laryngeal primary and metastatic squamous cell carcinoma cell lines. However, the protocol is suitable also for other solid cancer cell lines.

Tumor microenvironment is an essential part of cancer growth and invasion. To mimic carcinoma progression, a biologically relevant human matrix is needed. This protocol introduces an improvement for the in vitro three-dimensional spheroid invasion assay by applying a human leiomyoma-based matrix. The protocol also introduces a computer-based cell invasion analysis.

Two-dimensional cell culture-based assays are commonly used in in vitro cancer research. However, they lack several basic elements that form the tumor ...

Assessing Cell Viability and Death in 3D Spheroid Cultures of Cancer Cells

Three-dimensional spheroids of cancer cells are important tools for both cancer drug screens and for gaining mechanistic insight into cancer cell biology. The power of this preparation lies in its ability to mimic many aspects of the in vivo conditions of tumors while being fast, cheap, and versatile enough to allow relatively high-throughput screening. The spheroid culture conditions can recapitulate the physico-chemical gradients in a tumor, including the increasing extracellular acidity, increased lactate, and decreasing glucose and oxygen availability, from the spheroid periphery to its core. Also, the mechanical properties and cell-cell interactions of in vivo tumors are in part mimicked by this model. The specific properties and consequently the optimal growth conditions, of 3D spheroids, differ widely between different types of cancer cells. Furthermore, the assessment of cell viability and death in 3D spheroids requires methods that differ in part from those employed for 2D cultures. Here we describe several protocols for preparing 3D spheroids of cancer cells, and for using such cultures to assess cell viability and death in the context of evaluating the efficacy of anticancer drugs.

Here, we present several simple methods for evaluating viability and death in 3D cancer cell spheroids, which mimic the physico-chemical gradients of in vivo tumors much better than the 2D culture. The spheroid model, therefore, allows evaluation of the cancer drug efficacy with improved translation to in vivo conditions.

Three-dimensional spheroids of cancer cells are important tools for both cancer drug screens and for gaining mechanistic insight into cancer cell biology. ...

A 3D Spheroid Model for Glioblastoma

Two-dimensional (2D) cell cultures do not mimic in vivo tumor growth satisfactorily. Therefore, three-dimensional (3D) culture spheroid models were developed. These models may be particularly important in the field of neuro-oncology. Indeed, brain tumors have the tendency to invade the healthy brain environment. We describe herein an ideal 3D glioblastoma spheroid-based assay that we developed to study tumor invasion. We provide all technical details and analytical tools to successfully perform this assay.

Here, we describe an easy-to-use invasion assay for glioblastoma. This assay is suitable for glioblastoma stem-like cells. A Fiji macro for easy quantification of invasion, migration, and proliferation is also described.

Two-dimensional (2D) cell cultures do not mimic in vivo tumor growth satisfactorily. Therefore, three-dimensional (3D) culture spheroid models were ...