Name: measurement of the compressibility of cell and nucleus based on acoustofluidic microdevice
Uploaded: 2022-07-14T15:00:00
Description: Watch this Scientific Journal Video about Measurement of the Compressibility of Cell and Nucleus Based on Acoustofluidic Microdevice at JoVE.com

This study was supported by the National Natural Science Foundation of China (Grant numbers 12075330 and U1932165) and the Natural Science Foundation of Guangdong Province, China (Grant number 2020A1515010270).

1. Fabricating and assembly of the acoustofluidic microdevice
<ol>
	<li>Fabrication of the microfluidic chip.
	<ol>
		<li>Design a single-channel chip with only one inlet and outlet as shown in Figure 1. For measuring cells, keep the rectangular cross-section of the microchannel at 740 &#181;m wide and 100 &#181;m deep. For measuring cell nucleus, change the width and depth of the microchannel to 250 &#181;m and 100 &#181;m, respectively.</li>
		<li>Prepare the microchanne...

<ol>
	<li>Wirtz, D., Konstantopoulos, K., Searson, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+physics+of+cancer:+the+role+of+physical+interactions+and+mechanical+forces+in+metastasis.">The physics of cancer: the role of physical interactions and mechanical forces in metastasis.</a> Nature Reviews. Cancer. 11 (7), 512-522 (2011).</li><li>Frame, F. 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=HDAC+inhibitor+confers+radiosensitivity+to+prostate+stem-like+cells.">HDAC inhibitor confers radiosensitivity to prostate stem-like cells.</a> British Journal of Cancer. 109 (12), 3023-3033 (2013).</li><li>Tseng, Y., Kole, T. 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T., Su, H. -. W., Bruus, H., Voldman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Iso-acoustic+focusing+of+cells+for+size-insensitive+acousto-mechanical+phenotyping.">Iso-acoustic focusing of cells for size-insensitive acousto-mechanical phenotyping.</a> Nature Communications. 7 (1), 11556 (2016).</li><li>Cushing, K. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasound+characterization+of+microbead+and+cell+suspensions+by+speed+of+sound+measurements+of+neutrally+buoyant+samples.">Ultrasound characterization of microbead and cell suspensions by speed of sound measurements of neutrally buoyant samples.</a> Analytical Chemistry. 89 (17), 8917-8923 (2017).</li><li>Riaud, A., Wang, W., Thai, A. L. P., Taly, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+characterization+of+cells+and+microspheres+sorted+by+acoustophoresis+with+in-line+resistive+pulse+sensing.">Mechanical characterization of cells and microspheres sorted by acoustophoresis with in-line resistive pulse sensing.</a> Physical Review Applied. 13 (3), 034058 (2020).</li><li>Petersson, F., Aberg, L., Sw&#228;rd-Nilsson, A. -. M., Free Laurell, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=flow+acoustophoresis:+microfluidic-based+mode+of+particle+and+cell+separation.">flow acoustophoresis: microfluidic-based mode of particle and cell separation.</a> Analytical Chemistry. 79 (14), 5117-5123 (2007).</li><li>Griwatz, C., Brandt, B., Assmann, G., Z&#228;nker, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+immunological+enrichment+method+for+epithelial+cells+from+peripheral+blood.">An immunological enrichment method for epithelial cells from peripheral blood.</a> Journal of Immunological Methods. 183 (2), 251-265 (1995).</li><li>Katholnig, K., Poglitsch, M., Hengstschl&#228;ger, M., Weichhart, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lysis+gradient+centrifugation:+a+flexible+method+for+the+isolation+of+nuclei+from+primary+cells.">Lysis gradient centrifugation: a flexible method for the isolation of nuclei from primary cells.</a> Methods in Molecular Biology. 1228, 15-23 (2015).</li><li>Fu, Q., Zhang, Y., Huang, T., Liang, Y., Liu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+cell+compressibility+changes+during+epithelial-mesenchymal+transition+based+on+acoustofluidic+microdevice.">Measurement of cell compressibility changes during epithelial-mesenchymal transition based on acoustofluidic microdevice.</a> Biomicrofluidics. 15 (6), 064101 (2021).</li><li>Zhang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ionizing+radiation-induced+DNA+damage+responses+affect+cell+compressibility.">Ionizing radiation-induced DNA damage responses affect cell compressibility.</a> Biochemical and Biophysical Research Communications. 603, 116-122 (2022).</li><li>Hao, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+properties+of+single+cells:+Measurement+methods+and+applications.">Mechanical properties of single cells: Measurement methods and applications.</a> Biotechnology Advances. 45, 107648 (2020).</li><li>Yousafzai, 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=Effect+of+neighboring+cells+on+cell+stiffness+measured+by+optical+tweezers+indentation.">Effect of neighboring cells on cell stiffness measured by optical tweezers indentation.</a> Journal of Biomedical Optics. 21 (5), 057004 (2016).</li><li>Wei, M. -. 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+comparative+study+of+living+cell+micromechanical+properties+by+oscillatory+optical+tweezers.">A comparative study of living cell micromechanical properties by oscillatory optical tweezers.</a> Optics Express. 16 (12), 8594-8603 (2008).</li><li>Khan, Z. S., Vanapalli, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+the+mechanical+properties+of+brain+cancer+cells+using+a+microfluidic+cell+squeezer+device.">Probing the mechanical properties of brain cancer cells using a microfluidic cell squeezer device.</a> Biomicrofluidics. 7 (1), 011806 (2013).</li><li>Hirawa, S., Masudo, T., Okada, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acoustic+recognition+of+counterions+in+ion-exchange+resins.">Acoustic recognition of counterions in ion-exchange resins.</a> Analytical Chemistry. 79 (7), 3003-3007 (2007).</li><li>Joosse, S. A., Gorges, T. M., Biology Pantel, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=detection,+and+clinical+implications+of+circulating+tumor+cells.">detection, and clinical implications of circulating tumor cells.</a> EMBO Molecular Medicine. 7 (1), 1-11 (2015).</li><li>Martin, O. A., Anderson, R. L., Narayan, K., MacManus, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Does+the+mobilization+of+circulating+tumour+cells+during+cancer+therapy+cause+metastasis.">Does the mobilization of circulating tumour cells during cancer therapy cause metastasis.</a> Nature Reviews Clinical Oncology. 14 (1), 32-44 (2017).</li></ol>

Commonly used cell mechanics measurement methods are AFM, micropipette aspiration, microfluidics methods, parallel-plate technique, optical tweezers, optical stretcher, and acoustic methods20. Microfluidics methods can work with three approaches: micro-constriction, extensional flow, and shear flow. Among them, optical stretcher, optical tweezers, acoustic methods, extensional flow, and shear flow approaches are non-contact measurements. In contrast to contact measurements, non-contact measurement...

Cell mechanical properties play an important role in tumor metastasis, malignant transformation of cells, and radiosensitivity1,2. To gain an in-depth understanding of the role of cell mechanical properties in the above process, accurate measurement of cellular mechanics is critical, and the measurement should not cause damage to the cells for subsequent culture and analysis. The measurement process should be as fast as possible, otherwise cell viability may be affected if cells are removed from the cultivation environment for a long time.
Existing cell mechanics measurement methods face some limitations. Some methods, such as magnetic twisting cytometry, magnetic tweezers and particle-tracking microrheology, cause cell damage due to the introduction of particles into cells3,4,5. Methods that measure by contact with cells, such as atomic force microscope (AFM), micropipette aspiration, micro-constriction, and parallel-plate technique, are also prone to cell damage and the throughput is difficult to increase6,7,8. In addition, ionizing radiation will flatten cells and increase their adhesion9; it is therefore necessary to measure whole cell mechanics in suspension.
In response to the above challenges, a cell mechanics measurement system based on acoustofluidic method10,11,12,13,14 has been developed. The channel width is matched to the acoustic half wavelength, thus creating a standing wave node at the midline of the microchannel. Under the action of acoustic radiation force, the cells or standard beads can move to the acoustic pressure node. Since the physical properties of the standard beads (size, density, and compressibility) are known, the acoustic energy density can be determined. Then, the cell compressibility can be obtained by recording the motion trajectories of cells in the acoustic field. Non-destructive high-throughput measurement of cells in suspension state can be achieved. This paper will introduce the design of the microfluidic chip, the establishment of the system and the measurement steps. Measurement of various types of tumor cells has been carried out to verify the accuracy of the method. The application scope of this method had been extended to subcellular structures (such as nucleus) by adjusting the resonance frequency of the piezoelectric ceramic and the width of the microchannel. In addition, the changes in cell compressibility after drug-induced EMT or X-ray irradiation with different doses were investigated. The results demonstrate the broad applicability of this method as a powerful tool for studying the correlation between biochemical changes and cellular mechanical properties.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.25% trypsin(1x)</td>
			<td>GIBCO</td>
			<td>15050-065</td>
			<td></td>
		</tr>
		<tr>
			<td>502 glue</td>
			<td>Evo-bond</td>
			<td></td>
			<td>cyanoacrylate glue</td>
		</tr>
		<tr>
			<td>A549</td>
			<td>ATCC</td>
			<td>CCL-185</td>
			<td>lung adenocarcinoma</td>
		</tr>
		<tr>
			<td>Cytonucleoprotein and cytoplasmic protein extraction kit</td>
			<td>Beyotime</td>
			<td>P0027</td>
			<td>Contains cytoplasmic protein extraction reagents A and B</td>
		</tr>
		<tr>
			<td>Dulbecco&#8217;s modified Eagle medium (DMEM)&#160;</td>
			<td>corning</td>
			<td>10-013-CVRC</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Srum(FBS)</td>
			<td>AUSGENEX</td>
			<td>FBS500-S</td>
			<td></td>
		</tr>
		<tr>
			<td>HCT116</td>
			<td>ATCC</td>
			<td>CCL247</td>
			<td>colorectal carcinoma</td>
		</tr>
		<tr>
			<td>Heat-resistant glass</td>
			<td>Pyrex</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Leibovitz&#8217;s L-15 medium&#160;</td>
			<td>GIBCO</td>
			<td>11415-064</td>
			<td></td>
		</tr>
		<tr>
			<td>MCF-7</td>
			<td>ATCC</td>
			<td>HTB-22&#160;</td>
			<td>breast Adenocarcinoma</td>
		</tr>
		<tr>
			<td>MDA-MB-231</td>
			<td>ATCC</td>
			<td>HTB-26&#160;</td>
			<td>breast Adenocarcinoma</td>
		</tr>
		<tr>
			<td>Minimum Essential Medium (MEM)</td>
			<td>corning</td>
			<td>10-010-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin</td>
			<td>GIBCO</td>
			<td>15140-122</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate buffer</td>
			<td>corning</td>
			<td>21-040-cvc</td>
			<td></td>
		</tr>
		<tr>
			<td>PMSF</td>
			<td>Beyotime</td>
			<td>ST506</td>
			<td>100mM</td>
		</tr>
		<tr>
			<td>Polybead Polystyrene Red Dyed Microsphere&#160;</td>
			<td>polysciences</td>
			<td>15714</td>
			<td>The diameter of microshpere is 6.00&#181;m</td>
		</tr>
		<tr>
			<td>propidium iodide(PI)</td>
			<td>Sigma-Aldrich</td>
			<td>P4170</td>
			<td></td>
		</tr>
		<tr>
			<td>SYLGARD 184Silicone ELASTOMER</td>
			<td>Dow-Corning</td>
			<td>1673921</td>
			<td>Contains prepolymers and curing agents</td>
		</tr>
		<tr>
			<td>Trypan Blue</td>
			<td>Beyotime</td>
			<td>C0011</td>
			<td></td>
		</tr>
	</tbody>
</table>

measurement of the compressibility of cell and nucleus based on acoustofluidic microdevice

Cell mechanics play an important role in tumor metastasis, malignant transformation of cells, and radiosensitivity. During these processes, studying the mechanical properties of the cells is often challenging. Conventional measurement methods based on contact such as compression or stretching are prone to cause cell damage, affecting measurement accuracy and subsequent cell culture. Measurements in adherent state can also affect accuracy, especially after irradiation since ionizing radiation will flatten cells and enhance adhesion. Here, a cell mechanics measurement system based on acoustofluidic method has been developed. The cell compressibility can be obtained by recording the cell motion trajectory under the action of the acoustic force, which can realize fast and non-destructive measurement in suspended state. This paper reports in detail the protocols for chip design, sample preparation, trajectory recording, parameter extraction and analysis. The compressibility of different types of tumor cells was measured based on this method. Measurement of the compressibility of nucleus was also achieved by adjusting the resonance frequency of the piezoelectric ceramic and the width of the microchannel. Combined with the molecular level verification of immunofluorescence experiments, the cell compressibility before and after drug-induced epithelial to mesenchymal transition (EMT) were compared. Further, the change of cell compressibility after X-ray irradiation with different doses was revealed. The cell mechanics measurement method proposed in this paper is universal and flexible and has broad application prospects in scientific research and clinical practice.

Here, the work presented a protocol for the construction of a fast and non-destructive cell compressibility measuring system based on acoustofluidic microdevice and demonstrated its advantages for measuring cell and nucleus under different situations. Figure 1 shows the schematic of the microfluidic channel. The components and assembly of the acoustofluidic microdevice are shown in Figure 2. Figure 3 shows the setup of the measureme...

Watch this Scientific Journal Video about Measurement of the Compressibility of Cell and Nucleus Based on Acoustofluidic Microdevice at JoVE.com

Measurement of the Compressibility of Cell and Nucleus Based on Acoustofluidic Microdevice

Here a protocol is presented to build a fast and non-destructive system for measuring cell or nucleus compressibility based on acoustofluidic microdevice. Changes in mechanical properties of tumor cells after epithelial-mesenchymal transition or ionizing radiation were investigated, demonstrating the application prospect of this method in scientific research and clinical practice.

Cell mechanics play an important role in tumor metastasis, malignant transformation of cells, and radiosensitivity. During these processes, studying the ...

Cell mechanics play an important role in tumor metastasis, malignant transformation of cells, and radiosensitivity. Acoustofluidic method can realize fast and non-destructive measurement in suspended states. This technique can be used for mirroring the change of self compressibility during epithelial to mesenchymal transition and separating circulating tumor cells, showing its application prospects in cancer diagnosis.To begin, bind the PDMS block to the chip by punching holes in the PDMS block for inlet and outlet ports with a one millimeter diameter hollow needle. Then put the PDMS blocks and chip with the backside up in a plasma cleaner for one minute. After aligning the holes on the PDMS blocks with the chip inlet and outlet, gently press the PDMS blocks to the chip for 15 seconds, resulting in bonding to occur between the PDMS blocks and the surface of the chip.To connect the PTFE catheter to the chip, cut two pieces of catheter with an inner diameter of 0.8 millimeter and a length of 10 centimeter. Bend a stainless steel needle with an inner diameter of 0.7 millimeter and a length of 1.5 centimeter by 90 degrees into an L shape and connect it to one end of the catheter. Insert the stainless steel needles to the holes of the PDMS blocks.For the inlet, connect a 19 gauge dispensing needle to the other end of the catheter as a connector for a syringe. Afterward, inject deionized water to test the tightness of the overall channel. For a piezoelectric ceramic assembly, select precut piezoelectric ceramic sheets with a width of five millimeter.Then weld wires on both sides of the piezoelectric ceramic at one end. Glue the piezoelectric ceramic to the middle of the back of the chip by placing a drop of cyanoacrylate glue on the piezoelectric ceramic. Smooth the glue with the toothpick and remove the excess glue.Then quickly press it on the chip and continue to press for about one minute. To mount the micro device, cut a piece of PDMS as the base of the micro device and stick one side of the base to the inlet and outlet PDMS blocks and the other side to a transparent glass slide using double-sided tape. Fix the whole microdevice to the microscope stage to keep the chip in one focal plane.To prepare the polystyrene standard particle solutions add 0.05 milliliters of polystyrene particle solution to 10 milliliter of PBS and mix well. Then prepare the cell suspensions by washing the adherent cells at 90%confluency with PBS. Add 500 microliters of 0.25 Trypsin for one to two minutes at room temperature.After removing the Trypsin, add one milliliter complete medium and form a cell suspension by pipetting. Next centrifuge the cell suspension at 100 G for five minutes. Remove the supernatant and resuspend in 0.5 to one milliliter of PBS in order to obtain a cell suspension.Then cells were counted with a hemocytometer and the concentration was about 300 to 500, 000 cells per milliliter. After a preparing the cell nucleus suspension as demonstrated previously, remove the supernatant and add 200 microliters of cytoplasmic protein extraction reagent A per 20 microliters cell palette and mix well. Then vortex the above mixture at 220 G for five seconds and place on ice bath for 10 minutes.Next, add 10 microliters of cytoplasmic protein extraction reagent B to the solution after incubation. After vortexing, place on ice bath for one minute and vortex again at 220 G for five seconds. Then, finally centrifuge at 1000 G for five minutes at four degrees Celsius.Remove the supernatant and resuspend the palette in one milliliter of PBS. Then centrifuge at 1000 G at four degrees Celsius for four minutes. After removing the supernatant, resuspend in 100 microliters of PBS as cell nucleus suspension.Add trypan blue to the above cell nucleus suspension and stain at room temperature for four minutes. Next, count the number of nuclei under the inverted microscope with a 10x objective. Dilute the above cell nucleus suspension with PBS buffer to a concentration of 200 to 300, 000 nucleus per milliliter.Then filter the cell nucleus suspension through a 70 micrometer sieve. To set up the measurement system, turn on the light source of the microscope and open the camera software. Use the 4x objective to find the middle position of the microchannel, that is, the position of the piezoelectric ceramic.After connecting the wires, weld them to the positive and negative terminals of the signal generator output of the piezoelectric ceramic respectively. Then place the syringe on the microinjection pump and connect it to the inlet catheter. To collect the fluid from the microchannel, place a small container at the end of the outlet catheter.To determine measurement parameters, aspirate the polystyrene particle solution with the syringe. Then inject the solution into the chip microchannel while avoiding air bubbles and in chip microchannel to ensure accurate measurement. Set the output of the signal generator to a sign signal with a frequency of one megahertz and peak-to-peak voltage of 10 volts until it's observed that the particles move toward the midline of the microchannel and remain in forward motion along the midline after reaching the midline.After mixing one milliliter cell or nucleus suspension with the standard particle solution at the ratio of one to one, inject it into the microchannel with a syringe to measure cells and nuclei. Start recording with CCD camera when the cells or nuclei enter the field of view and turn on the signal generator. Then rinse the microchannel with deionized water, 75%alcohol, and deionized water in sequence for later use.The movement of the cells and particles was observed under the action of the acoustic field force towards the midline of the microchannel at different time intervals. The calculation of energy, density, and cell compressibility were performed and acoustic energy density and the measured motion trajectory for the particle was obtained from the best fitting result. The high purity and intact nuclei were isolated from cells and nucleus compressibility measurement was achieved by obtaining the motion trajectory of the nucleus.The compressibility of different types of cancer cells and cells after drug-induced EMT or x-ray irradiation with different doses was measured and compared. The measured cells were collected and it was found that there was no significant difference in cell proliferation and viability compared to the untreated group after 48 hours of culture. Indicating that the compressibility measurement has no effect on cell proliferation and survival.The most important thing is to fine tune the frequency of the signal until it's observed that particles move towards the midline of the microchannel.

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Cancer Research

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

Drosophila melanogaster has emerged as a powerful experimental system for functional and mechanistic studies of tumor development and progression in the context of a whole organism. Sophisticated techniques to generate genetic mosaics facilitate induction of visually marked, genetically defined clones surrounded by normal tissue. The clones can be analyzed through diverse molecular, cellular and omics approaches. This study describes how to generate fluorescently labeled clonal tumors of varying malignancy in the eye/antennal imaginal discs (EAD) of Drosophila larvae using the Mosaic Analysis with a Repressible Cell Marker (MARCM) technique. It describes procedures how to recover the mosaic EAD and brain from the larvae and how to process them for simultaneous imaging of fluorescent transgenic reporters and antibody staining. To facilitate molecular characterization of the mosaic tissue, we describe a protocol for isolation of total RNA from the EAD. The dissection procedure is suitable to recover EAD and brains from any larval stage. The fixation and staining protocol for imaginal discs works with a number of transgenic reporters and antibodies that recognize Drosophila proteins. The protocol for RNA isolation can be applied to various larval organs, whole larvae, and adult flies. Total RNA can be used for profiling of gene expression changes using candidate or genome-wide approaches. Finally, we detail a method for quantifying invasiveness of the clonal tumors. Although this method has limited use, its underlying concept is broadly applicable to other quantitative studies where cognitive bias must be avoided.

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

This protocol demonstrates how to generate fluorescently marked, genetically defined clonal tumors in the Drosophila eye/antennal imaginal discs (EAD). It describes how to dissect the EAD and brain from the third instar larvae and how to process them to visualize and quantify gene expression changes and tumor invasiveness.

Drosophila melanogaster has emerged as a powerful experimental system for functional and mechanistic studies of tumor development and progression in the ...

Evaluation of the Cell Invasion and Migration Process: A Comparison of the Video Microscope-based Scratch Wound Assay and the Boyden Chamber Assay

The invasion and migration abilities of tumor cells are main contributors to cancer progression and recurrence. Many studies have explored the migration and invasion abilities to understand how cancer cells disseminate, with the aim of developing new treatment strategies. Analysis of the cellular and molecular basis of these abilities has led to the characterization of cell mobility and the physicochemical properties of the cytoskeleton and cellular microenvironment. For many years, the Boyden chamber assay and the scratch wound assay have been the standard techniques to study cell invasion and migration. However, these two techniques have limitations. The Boyden chamber assay is difficult and time consuming, and the scratch wound assay has low reproducibility. Development of modern technologies, especially in microscopy, has increased the reproducibility of the scratch wound assay. Using powerful analysis systems, an &#34;in-incubator&#34; video microscope can be used to provide automatic and real-time analysis of cell migration and invasion. The aim of this paper is to report and compare the two assays used to study cell invasion and migration: the Boyden chamber assay and an optimized in vitro video microscope-based scratch wound assay.

This study reports two different methods for the analysis of cell invasion and migration: the Boyden chamber assay and the in vitro video microscope-based wound-healing assay. The protocols for these two experiments are described, and their benefits and disadvantages are compared.

The invasion and migration abilities of tumor cells are main contributors to cancer progression and recurrence. Many studies have explored the migration ...

Elastic Staining on Paraffin-embedded Slides of pT3N0M0 Gastric Cancer Tissue

The elastic lamina, which is usually located in the sub-mesothelial layer, adjacent to the peritoneum mesothelial cells, is amphiphilic on hematoxylin and eosin (H&amp;E) staining but can be visualized through elastic staining. One of the important benefits of elastic staining is that it makes it easy to determine whether tumor cells have invaded beyond the elastic lamina. This helps in examining the extent of peritoneal surface invasion, thereby distinguishing the pT3 and pT4 stages in gastrointestinal cancer. In this study, we present a protocol to identify elastic fibers in the formalin-fixed, paraffin-embedded pT3N0M0 gastric cancer tissue sections. We prepare 5-&#181;m paraffin sections fixed on slides, and then all the slides are deparaffinated and rehydrated during the staining procedure. Subsequently, all the sections are oxidized by potassium permanganate, bleached by oxalic acid, stained by elastic staining, and counterstained by Van Gieson's. Finally, we examine the effect of staining; elastic lamina is stained blue-black and collagen fibers are stained red, while the cancer cells are stained in varying shades of yellow. We also describe in detail the methods used for determining the positional relationship between cancer cells and elastic lamina. This method is simple, low-cost, and widely applicable in the identification of peritoneal surface invasion in gastrointestinal cancer because of its outstanding selectivity for elastic fibers and authentic results.

Here, we present a protocol of elastic staining to identify elastic fibers in pT3N0M0 gastric cancer tissues on formalin-fixed, paraffin-embedded sections. Subsequently, we describe a method to determine whether tumor cells invade beyond the elastic lamina.

The elastic lamina, which is usually located in the sub-mesothelial layer, adjacent to the peritoneum mesothelial cells, is amphiphilic on hematoxylin and ...

Analysis of Cancer Cell Invasion and Anti-metastatic Drug Screening Using Hydrogel Micro-chamber Array (HMCA)-based Plates

Cancer metastasis is known to cause 90% of cancer lethality. Metastasis is a multistage process which initiates with the penetration/invasion of tumor cells into neighboring tissue. Thus, invasion is a crucial step in metastasis, making the invasion process research and development of anti-metastatic drugs, highly significant. To address this demand, there is a need to develop 3D in vitro models which imitate the architecture of solid tumors and their microenvironment most closely to in vivo state on one hand, but at the same time be reproducible, robust and suitable for high yield and high content measurements. Currently, most invasion assays lean on sophisticated microfluidic technologies which are adequate for research but not for high volume drug screening. Other assays using plate-based devices with isolated individual spheroids in each well are material consuming and have low sample size per condition. The goal of the current protocol is to provide a simple and reproducible biomimetic 3D cell-based system for the analysis of invasion capacity in large populations of tumor spheroids. We developed a 3D model for invasion assay based on HMCA imaging plate for the research of tumor invasion and anti-metastatic drug discovery. This device enables the production of numerous uniform spheroids per well (high sample size per condition) surrounded by ECM components, while continuously and simultaneously observing and measuring the spheroids at single-element resolution for medium throughput screening of anti-metastatic drugs. This platform is presented here by the production of HeLa and MCF7 spheroids for exemplifying single cell and collective invasion. We compare the influence of the ECM component hyaluronic acid (HA) on the invasive capacity of collagen surrounding HeLa spheroids. Finally, we introduce Fisetin (invasion inhibitor) to HeLa spheroids and nitric oxide (NO) (invasion activator) to MCF7 spheroids. The results are analyzed by in-house software which enables semi-automatic, simple and fast analysis which facilitates multi-parameter examination.

Analysis of Cancer Cell Invasion and Anti-metastatic Drug Screening Using Hydrogel Micro-chamber Array HMCA-based Plates

A HMCA-based imaging plate is presented for invasion assay performance. This plate facilitates the formation of three-dimensional (3D) tumor spheroids and the measurement of cancer cell invasion into the extracellular matrix (ECM). The invasion assay quantification is achieved by semi-automatic analysis.

Cancer metastasis is known to cause 90% of cancer lethality. Metastasis is a multistage process which initiates with the penetration/invasion of tumor ...

A Three-dimensional Thymic Culture System to Generate Murine Induced Pluripotent Stem Cell-derived Tumor Antigen-specific Thymic Emigrants

The inheritance of pre-rearranged T cell receptors (TCRs) and their epigenetic rejuvenation make induced pluripotent stem cell (iPSC)-derived T cells a promising source for adoptive T cell therapy (ACT). However, classical in vitro methods for producing regenerated T cells from iPSC result in either innate-like or terminally differentiated T cells, which are phenotypically and functionally distinct from na&#239;ve T cells. Recently, a novel three-dimensional (3D) thymic culture system was developed to generate a homogenous subset of CD8&#945;&#946;+ antigen-specific T cells with a na&#239;ve T cell-like functional phenotype, including the capacity for proliferation, memory formation, and tumor suppression in vivo. This protocol avoids aberrant developmental fates, allowing for the generation of clinically relevant iPSC-derived T cells, designated as iPSC-derived thymic emigrants (iTE), while also providing a potent tool to elucidate the subsequent functions necessary for T cell maturation after thymic selection.

This article describes a novel method to generate tumor antigen-specific induced pluripotent stem cell-derived thymic emigrants (iTE) by a three-dimensional (3D) thymic culture system. iTE are a homogenous subset of T cells closely related to na&#239;ve T cells with the capacity for proliferation, memory formation, and tumor suppression.

The inheritance of pre-rearranged T cell receptors (TCRs) and their epigenetic rejuvenation make induced pluripotent stem cell (iPSC)-derived T cells a ...

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 ...

Cell Cycle-specific Measurement of &#947;H2AX and Apoptosis After Genotoxic Stress by Flow Cytometry

The presented method or slightly modified versions have been devised to study specific treatment responses and side effects of various anti-cancer treatments as used in clinical oncology. It enables a quantitative and longitudinal analysis of the DNA damage response after genotoxic stress, as induced by radiotherapy and a multitude of anti-cancer drugs. The method covers all stages of the DNA damage response, providing endpoints for induction and repair of DNA double-strand breaks (DSBs), cell cycle arrest and cell death by apoptosis in case of repair failure. Combining these measurements provides information about cell cycle-dependent treatment effects and thus allows an in-depth study of the interplay between cellular proliferation and coping mechanisms against DNA damage. As the effect of many cancer therapeutics including chemotherapeutic agents and ionizing radiation is limited to or strongly varies according to specific cell cycle phases, correlative analyses rely on a robust and feasible method to assess the treatment effects on the DNA in a cell cycle-specific manner. This is not possible with single-endpoint assays and an important advantage of the presented method. The method is not restricted to any particular cell line and has been thoroughly tested in a multitude of tumor and normal tissue cell lines. It can be widely applied as a comprehensive genotoxicity assay in many fields of oncology besides radio-oncology, including environmental risk factor assessment, drug screening and evaluation of genetic instability in tumor cells.

Cell Cycle-specific Measurement of &amp;#947;H2AX and Apoptosis After Genotoxic Stress by Flow Cytometry

The presented method combines the quantitative analysis of DNA double-strand breaks (DSBs), cell cycle distribution and apoptosis to enable cell cycle-specific evaluation of DSB induction and repair as well as the consequences of repair failure.

The presented method or slightly modified versions have been devised to study specific treatment responses and side effects of various anti-cancer ...

Using Human Induced Pluripotent Stem Cells for the Generation of Tumor Antigen-specific T Cells

The generation and expansion of functional T cells in vitro can lead to a broad range of clinical applications. One such use is for the treatment of patients with advanced cancer. Adoptive T cell transfer (ACT) of highly enriched tumor antigen-specific T cells has been shown to cause durable regression of metastatic cancer in some patients. However, during expansion, these cells may become exhausted or senescent, limiting their effector function and persistence in vivo. Induced pluripotent stem cell (iPSC) technology may overcome these obstacles by leading to in vitro generation of large numbers of less differentiated tumor antigen-specific T cells. Human iPSC (hiPSC) have the capacity to differentiate into any type of somatic cell, including lymphocytes, which retain the original T cell receptor (TCR) genomic rearrangement when a T cell is used as a starting cell. Therefore, reprogramming of human tumor antigen-specific T cells to hiPSC followed by redifferentiation to T cell lineage has the potential to produce rejuvenated tumor antigen-specific T cells. Described here is a method for generating tumor antigen-specific CD8&#945;&#946;+ single positive (SP) T cells from hiPSC using OP9/DLL1 co-culture system. This method is a powerful tool for in vitro T cell lineage generation and will facilitate the development of in vitro derived T cells for use in regenerative medicine and cell-based therapies.

This article describes a method to generate functional tumor antigen-specific induced pluripotent stem cell-derived CD8&#945;&#946;+ single positive T cells using OP9/DLL1 co-culture system.

The generation and expansion of functional T cells in vitro can lead to a broad range of clinical applications. One such use is for the treatment of ...

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 ...

Detection of Cell-Free DNA in Blood Plasma Samples of Cancer Patients

Identifying mutations in tumors of cancer patients is a very important step in disease management. These mutations serve as biomarkers for tumor diagnosis as well as for the treatment selection and its response in cancer patients. The current gold standard method for detecting tumor mutations involves a genetic test of tumor DNA by means of tumor biopsies. However, this invasive method is difficult to be performed repeatedly as a follow-up test of the tumor mutational repertoire. Liquid biopsy is a new and emerging technique for detecting tumor mutations as an easy-to-use and non-invasive biopsy approach.
Cancer cells multiply rapidly. In parallel, numerous cancer cells undergo apoptosis. Debris from these cells are released into a patient&#8217;s circulatory system, together with finely fragmented DNA pieces, called cell-free DNA (cfDNA) fragments, which carry tumor DNA mutations. Therefore, for identifying cfDNA based biomarkers using liquid biopsy technique, blood samples are collected from the cancer patients, followed by the separation of plasma and buffy coat. Next, plasma is processed for the isolation of cfDNA, and the respective buffy coat is processed for the isolation of a patient&#39;s genomic DNA. Both nucleic acid samples are then checked for their quantity and quality; and analyzed for mutations using next-generation sequencing (NGS) techniques.
In this manuscript, we present a detailed protocol for liquid biopsy, including blood collection, plasma, and buffy coat separation, cfDNA and germline DNA extraction, quantification of cfDNA or germline DNA, and cfDNA fragment enrichment analysis.

In this paper we present a detailed protocol for non-invasive liquid biopsy technique, including blood collection, plasma and buffy coat separation, cfDNA and germline DNA extraction, quantification of cfDNA or germline DNA, and cfDNA fragment enrichment analysis.

Identifying mutations in tumors of cancer patients is a very important step in disease management. These mutations serve as biomarkers for tumor diagnosis ...