Name: evaluation of biomarkers in glioma by immunohistochemistry on paraffin-embedded 3d glioma neurosphere cultures
Uploaded: 2019-01-09T15:00:00
Description: Watch this Scientific Journal Video about Evaluation of Biomarkers in Glioma by Immunohistochemistry on Paraffin-Embedded 3D Glioma Neurosphere Cultures at JoVE.com

This work was supported by National Institutes of Health/National Institute of Neurological Disorders &#38; Stroke (NIH/NINDS) Grants R37-NS094804, R01-NS074387, R21-NS091555 to M.G.C.; NIH/NINDS Grants R01-NS076991, R01-NS082311, and R01-NS096756 to P.R.L.; NIH/NINDS R01-EB022563; 1UO1CA224160; the Department of Neurosurgery; Leah&#39;s Happy Hearts to M.G.C. and P.R.L.; and RNA Biomedicine Grant F046166 to M.G.C. F.M.M. is supported by an F31 NIH/NINDS-F31NS103500. J.P. was supported by a Fulbright-Argentinian Ministry of Sports and Education Fellowship.

All methods described here have been approved by the Institutional Animal Care and Use Committee (IACUC) of the University of Michigan.
1. Generation of Brain Tumor Neurospheres Derived from a Mouse Model
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	<li>Before the dissection procedure, prepare neural stem cell media (NSC Media: DMEM/F12 with 1x B27 supplement, 1x N2 supplement, 1x normocin, and 1x antibiotic/antimycotic supplemented with human recombinant EGF and basic-FGF at concentrations of 20 ng/mL each). Fill a 1.5 mL tube w...

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In this article, we detail a versatile and reproducible method to perform immunohistochemistry on paraffin-embedded glioma NS, which maintain the characteristic 3D structure of tumor cells growing in the brain in situ. This technique possesses the following advantages over using cells plated onto glass or plastic surfaces: i) preservation of the 3D structure of NS; ii) avoiding of stress of cell dissociation before analysis of protein expression; iii) quenching of any endogenous fluorophore expression from genet...

Gliomas are primary solid tumors of the central nervous system classified by their phenotypic and genotypic characteristics according to the World Health Organization1. This classification incorporates the presence or absence of driver mutations, which represent an attractive source of biomarkers2. Biomarkers are biological characteristics that can be measured and evaluated to indicate normal and pathological processes, as well as pharmacological responses to a therapeutic intervention3. Biomarkers can be detected in tumor tissue and cells derived from glioma, enabling its biological characterization in different aspects. Some examples of glioma biomarkers include mutated isocitrate dehydrogenase 1 (IDH1), a mutant enzyme characteristic of lower-grade gliomas associated with better prognosis4. Mutated IDH1 is frequently expressed in combination with TP53 and alpha-thalassemia/mental retardation syndrome X-linked (ATRX)-inactivating mutations, defining a specific glioma subtype4,5. ATRX-inactivating mutations also occur in 44% of pediatric high-grade gliomas2,6 and have been associated with aggressive tumors and genomic instability6,7. In addition, pediatric diffuse intrinsic pontine gliomas (DIPG) are differentiated in subgroups according to the presence or absence of a K27M mutation in histone H3 gene H3F3A, or in the HIST1H3B/C gene1,6. Therefore, the introduction of molecular characterization permits the subdivision, study, and treatment of gliomas as separate entities, which will more allow the development of more targeted therapies for each subtype. In addition, the analysis of biomarkers can be used to evaluate different biological processes such as apoptosis8, autophagy9, cell cycle progression10, cell proliferation11, and cell differentiation12.
Genetically engineered animal models that harbor the genetic lesions present in human cancers are critical for the study of signaling pathways that mediate disease progression. Our laboratory has implemented the use of the Sleeping Beauty (SB) transposase system to develop genetically engineered mouse models of glioma harboring specific mutations that recapitulate human glioma subtypes13,14. These genetically engineered mouse models are used for generating tumor-derived NS, which enable in vitro studies in a 3D system, mirroring salient features present in the tumors in situ15. Also, the orthotopical transplantation of NS into mice can generate secondary tumors that retain features of the primary tumor and mimic the histopathological, genomic, and phenotypic properties of the corresponding primary tumor15.
In serum-free culture, brain tumor cells with stem cell properties can be enriched, and in the presence of epidermal growth factors (EGF) and fibroblast growth factors (FGF), they can be grown as single cell-derived colonies such as NS cultures. In this selective culture system, most differentiating or differentiated cells rapidly die, whereas stem cells divide and form the cellular clusters. This allows the generation of a NS culture that maintains glioma tumor features16,17,18. Glioma NS can be used to evaluate several aspects of tumor biology, including the analysis of biomarkers that have applications in diagnosis, prognosis, classification, state of tumor progression, and cell differentiation state. Here, we detail a protocol to generate glioma NS and embed the 3D cultures in paraffin to be used for IHC staining. One advantage of fixing and embedding glioma NS is that the morphology of NS is maintained better compared to the conventional cytospin method19, in which glioma NS are subjected to stressful manipulation for cell dissociation and become flattened. In addition, embedding quenches any endogenous fluorophore expression from genetically engineered tumor NS, enabling staining across the fluorescent spectra. The overall goal of this method is to preserve the 3D structure of glioma cells through a paraffin embedding process and enable characterization of glioma neurospheres using immunohistochemistry.

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			<td height="21" style="height:21px;width:305px;">Coated microtome blade HP35</td>
			<td style="width:191px;">Thermo Scientific</td>
			<td style="width:221px;">3150734</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Microtome RM 2135</td>
			<td style="width:191px;">Leica</td>
			<td style="width:221px;">MR2135</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:305px;">Formalin solution, neutral buffered, 10%</td>
			<td style="width:191px;">Sigma-aldrich</td>
			<td>HT501128-4L</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:305px;">Rabbit polyclonal anti-ATRX,</td>
			<td style="width:191px;">Santa Cruz Biotechnology</td>
			<td style="width:221px;">sc-15408</td>
			<td>IHC, 1:250 dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:305px;">Rabbit polyclonal anti-Ki-67</td>
			<td style="width:191px;">Abcam</td>
			<td style="width:221px;">Ab15580</td>
			<td>IHC, 1:1000 dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Rabbit polyclonal anti-OLIG2</td>
			<td>Millipore</td>
			<td>AB9610</td>
			<td>IHC, 1:500 dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Goat polyclonal anti-rabbit biotin-conjugated</td>
			<td style="width:191px;">Dako</td>
			<td style="width:221px;">E0432</td>
			<td>IHC, 1:1000 dilution</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:305px;">Vectastain Elite ABC HRP kit</td>
			<td style="width:191px;">Vector Laboratories Inc</td>
			<td style="width:221px;">PK-6100</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;">BETAZOID DAB CHROMOGEN KIT</td>
			<td style="width:191px;">Biocare medical</td>
			<td style="width:221px;">BDB2004 L/price till 12/18</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:305px;">N-2 Supplement</td>
			<td style="width:191px;">ThermoFisher</td>
			<td style="width:221px;">17502048</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:305px;">N-27 Supplement</td>
			<td style="width:191px;">ThermoFisher</td>
			<td style="width:221px;">A3582801</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:305px;">Accutase&#174; Cell Detachment Solution</td>
			<td style="width:191px;">Biolegend</td>
			<td style="width:221px;">423201</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:305px;">AGAROSE LE</td>
			<td style="width:191px;">GoldBio</td>
			<td style="width:221px;">A-201-1000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:305px;">Genesee Sc. Corporation</td>
			<td style="width:191px;">Olympus 15 ml</td>
			<td style="width:221px;">21-103</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:305px;">Genesee Sc. Corporation</td>
			<td style="width:191px;">TC-75 treated Flask</td>
			<td style="width:221px;">25-209</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:305px;">Genesee Sc. Corporation</td>
			<td style="width:191px;">TC-25 treated Flask</td>
			<td style="width:221px;">25-207</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:305px;">DMEM/F12</td>
			<td style="width:191px;">Gibco</td>
			<td style="width:221px;">11330-057</td>
			<td>NS media</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:305px;">HBSS</td>
			<td style="width:191px;">GibcoTM</td>
			<td style="width:221px;">14175-103</td>
			<td>balanced salt solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:305px;">C57BL/6</td>
			<td style="width:191px;">Taconic</td>
			<td style="width:221px;">B6-f</td>
			<td>C57BL/6 mouse</td>
		</tr>
	</tbody>
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evaluation of biomarkers in glioma by immunohistochemistry on paraffin-embedded 3d glioma neurosphere cultures

Analysis of protein expression in glioma is relevant for several aspects in the study of its pathology. Numerous proteins have been described as biomarkers with applications in diagnosis, prognosis, classification, state of tumor progression, and cell differentiation state. These analyses of biomarkers are also useful to characterize tumor neurospheres (NS) generated from glioma patients and glioma models. Tumor NS provide a valuable in vitro model to assess different features of the tumor from which they are derived and can more accurately mirror glioma biology. Here we describe a detailed method to analyze biomarkers in tumor NS using immunohistochemistry (IHC) on paraffin-embedded tumor NS.

To monitor tumor development and evaluate if the tumor has reached the size necessary to generate NS, we analyzed the luminescence emitted by tumors using bioluminescence. This allows the study of transduction efficiency in the pups and tumor progression by the luminescence signal of luciferase (Figure 1A and 1B). When the tumor size reaches a signal of 1 x 107 photons/s/cm2/sr (Figure 1</stron...

Watch this Scientific Journal Video about Evaluation of Biomarkers in Glioma by Immunohistochemistry on Paraffin-Embedded 3D Glioma Neurosphere Cultures at JoVE.com

Evaluation of Biomarkers in Glioma by Immunohistochemistry on Paraffin-Embedded 3D Glioma Neurosphere Cultures

Neurospheres grown as 3D cultures constitute a powerful tool to study glioma biology. Here we present a protocol to perform immunohistochemistry while maintaining the 3D structure of glioma neurospheres through paraffin embedding. This method enables the characterization of glioma neurosphere properties such as stemness and neural differentiation.

Analysis of protein expression in glioma is relevant for several aspects in the study of its pathology. Numerous proteins have been described as ...

This protocol is significant because can be used to study the presence of glioma biomarker by a method that preserves the 3D structure of tumor neurospheres. The main advantage of this protocol is that the morphology of neurospheres is maintained compared to cytospin method in which cells are subjected to stressful manipulation and become flattened. This method can be applied to any other tissue culture systems in which cells are cultured in 3D and maintenance of the structure is important.To begin, culture tumor neurospheres or NS in a T-25 flask until the cells are confluent. Elect the tumor NS in a 15 milliliter conical tube. Impellet the NS at 300 Gs for five minutes.After this, re-suspend the pellet in one milliliter of 10%formalin and incubate the tube at room temperature for 10 minutes. Add five milliliters of HBSS to the re-suspended NS.Impellet the cells as previously described. Place the tube containing the pellet on ice.Re-suspend the washed NS pellet in 500 microliters of two percent warm liquid agarose. And mix by a gentle pipetting or stirring. Place the agarose embedded NS on ice until the agarose polymerizes.Then remove the piece of agarose, holding the NS.Place the piece of agarose into a cassette for tissue processing. Set a water bath to 42 degrees Celsius. And carefully insert the blade into the microtome.Then place the paraffin block into the microtome. With one hand, press down on the lever that controls the thickness of each section located on the left hand side of the machine. Press the lever to the second stop to set the microtome to a 30 micrometer thickness.Turn the coarse hand wheel to begin trimming the block. Once the surface of the sample is almost exposed, set the lever that controls thickness to five or 10 micrometers. Stop trimming when the surface of the sample is reached.Fill an ice box with ice and just enough water to protect the paraffin block from directly touching the ice. Discard the old microtome blade and insert a new one for sectioning. Dry the paraffin block with gauze and place it on the microtome.Turn the coarse hand wheel to begin sectioning the paraffin. Then use a damp paintbrush to transfer the paraffin ribbon to the 42 degree Celsius water bath. Using the curve of the forceps, place the forceps in between two paraffin sections and push the sections apart gently.Use the damp paintbrush to push the separated sections onto positively charged adhesion microscope slides. First, melt the paraffin by incubating the slides in a metal rack at 60 degrees Celsius for 20 minutes. Then deparaffinize the slides via incubation in a re-hydration train at room temperature according to the text protocol.Store the slides in tap water to prevent non-specific antibody binding. After this, incubate the slides in citrate buffer at 125 degrees Celsius for 30 seconds and 90 degrees Celsius for 10 seconds. Allow the slides to cool before rinsing them five times with distilled water.Next, incubate the slides at room temperature in 0.3%hydrogen peroxide for 20 minutes. Then, wash the slides for five minutes, three times in washing buffer with gentle agitation. Incubate the slides overnight in a humidified chamber set to four degrees Celsius with diluted primary antibody.After this, wash the slides three times for five minutes with gentle agitation. Next, incubate the slides in diluted biotinylated secondary antibody at room temperature for an hour. Wash the slides three times for five minutes in washing buffer with gentle agitation.Then, incubate the slides in avidin-biotinylated horseradish peroxidase complex at room temperature in the dark for an hour. Repeat the wash as previously described. After this, incubate the slides with DAB hydrogen peroxide substrate brands for two to five minutes at room temperature.Rinse the slides with tap water and dip the slides in hematoxylin solution to counterstain them. Then rinse the slides thoroughly in tap water until the water runs clear. Dehydrate the slides according to the text protocol.Finally, coverslip the slides with a xylene-based mounting medium and allow them dry on a flat surface at room temperature. In this protocol, NS are fixed and embedded in agarose and paraffin. And then they are stained for specific glioma biomarkers.The expression level of ATRX, a chaperone protein that mediates chromatin structure, is low. Ki67, a biomarker of cell proliferation, is positive in the glioma NS.Finally, the NS are also positive for OLIG2, a transcription factor that mediates oligodendrocyte differentiation. The most important thing to remember is to re-suspend the cells well in the warm agarose before transferring to ice, to ensure an even distribution of neurospheres.

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A Protocol for Rapid Post-mortem Cell Culture of Diffuse Intrinsic Pontine Glioma (DIPG)

Diffuse Intrinsic Pontine Glioma (DIPG) is a childhood brainstem tumor that carries a universally fatal prognosis. Because surgical resection is not a viable treatment strategy and biopsy is not routinely performed, the availability of patient samples for research is limited. Consequently, efforts to study this disease have been challenged by a paucity of faithful disease models. To address this need, we describe here a protocol for the rapid processing of post-mortem autopsy tissue samples in order to generate durable patient-derived cell culture models that can be used in in vitro assays or in vivo orthotopic xenograft experiments. These models can be used to screen for potential drug targets and to study fundamental pathobiological processes within DIPG. This protocol can further be extended to analyze and isolate tumor and microenvironmental cells using Fluorescence-activated Cell Sorting (FACS), which enables subsequent analysis of gene expression, protein expression, or epigenetic modifications of DNA at the bulk cell or single cell level. Finally, this protocol can also be adapted to generate patient-derived cultures for other central nervous system tumors.

A Protocol for Rapid Post-mortem Cell Culture of Diffuse Intrinsic Pontine Glioma DIPG

This protocol describes a method for the rapid processing of post-mortem diffuse intrinsic pontine glioma samples for the establishment of patient-derived cell culture models or direct characterization of tumor and microenvironmental cells.

Diffuse Intrinsic Pontine Glioma (DIPG) is a childhood brainstem tumor that carries a universally fatal prognosis. Because surgical resection is not a ...

Four-color Fluorescence Immunohistochemistry of T-cell Subpopulations in Archival Formalin-fixed, Paraffin-embedded Human Oropharyngeal Squamous Cell Carcinoma Samples

The four-color fluorescence immunohistochemistry (IHC) technique is a method to quantify cell populations of interest while taking into account their relative distribution and their localization in the tissue. This technique has been extensively applied to study the immune infiltrate in various tumor types. The tumor microenvironment is infiltrated by immune cells that are attracted to the tumor site. Different immune cell populations have been found to play different roles in the tumor microenvironment and to have a different impact on the outcome of disease. This manuscript describes the use of multiparameter fluorescence IHC on oropharyngeal squamous cell carcinoma (OPSCC) as an example. This technique can be extended to other tissue samples and cell types of interest. In the presented study, we analyzed the intraepithelial and stromal compartment of a large OPSCC cohort (n = 162). We focused on total T lymphocytes (CD3+), immunosuppressive regulatory T cells (Tregs; i.e., FoxP3+), and T helper 17 (Th17) cells (i.e., IL-17+CD3+) using a nuclear counterstain to distinguish tumor epithelium from stroma. A high number of T cells was found to be correlated with improved disease-free survival in patients with a low number of intratumoral IL-17+ non-T cells. This suggests that IL-17+ non-T cells may be correlated with a poor immune response in OPSCC, which is in agreement with the correlation described between IL-17 and poor survival in cancer patients. Currently, novel multiparameter fluorescence IHC techniques are being developed using up to 7 different fluorochromes and will enable the more precise characterization and localization of immune cells in the tumor microenvironment.

Multiparameter fluorescence immunohistochemistry can be used to assess the number, relative distribution, and localization of immune cell populations in the tumor microenvironment. This manuscript describes the use of this technique to analyze T-cell subpopulations in oropharyngeal cancer.

The four-color fluorescence immunohistochemistry (IHC) technique is a method to quantify cell populations of interest while taking into account their ...

Determination of Protein Expression Level in Cultured Cells by Immunocytochemistry on Paraffin-embedded Cell Blocks

Immunofluorescent staining is currently the method of choice for determination of protein expression levels in cell-culture systems when morphological information is also necessary. The protocol of immunocytochemical staining on paraffin-embedded cell blocks, presented herein, is an excellent alternative to immunofluorescent staining on non-paraffin-embedded fixed cells. In this protocol, a paraffin cell block from HeLa cells was prepared using the thromboplastin-plasma method, and immunocytochemistry was performed for the evaluation of two proliferation markers, CKAP2 and Ki-67. The nuclei and cytoplasmic morphology of the HeLa cells were well preserved in the cell-block slides. At the same time, the CKAP2 and Ki-67 staining patterns in the immunocytochemistry were quite similar to those in immunohistochemical staining in paraffin cancer tissues. With modified cell-culture conditions, including pre-incubation of HeLa cells under serum-free conditions, the effect could be evaluated while preserving architectural information. In conclusion, immunocytochemistry on paraffin-embedded cell blocks is an excellent alternative to immunofluorescent staining.

Currently, immunofluorescent staining on fixed cells is the method of choice for determination of protein expression levels when morphological information is also necessary. This protocol presented herein provides for an alternative method of immunocytochemistry on paraffin-embedded cell blocks.

Immunofluorescent staining is currently the method of choice for determination of protein expression levels in cell-culture systems when morphological ...

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 ...

Real-Time Monitoring of Human Glioma Cell Migration on Dorsal Root Ganglion Axon-Oligodendrocyte Co-Cultures

Glioblastoma is one of the most aggressive human cancers due to extensive cellular heterogeneity and the migration properties of hGCs. In order to better understand the molecular mechanisms underlying glioma cell migration, an ability to study the interaction between hGCs and axons within the tumor microenvironment is essential. In order to model this cellular interaction, we developed a mixed culture system consisting of hGCs and dorsal root ganglia (DRG) axon-oligodendrocyte co-cultures. DRG cultures were selected because they can be isolated efficiently and can form the long, extensive projections which are ideal for migration studies of this nature. Purified rat oligodendrocytes were then added on purified rat DRG axons and induced to myelinate. After confirming the formation of compact myelin, hGCs were finally added to the co-culture and their interactions with DRG axons and oligodendrocytes was monitored in real-time using time-lapse microscopy. Under these conditions, hGCs form tumor-like aggregate structures that express GFAP and Ki67, migrate along both myelinated and non-myelinated axonal tracks and interact with these axons through the formation of pseudopodia. Our ex vivo co-culture system can be used to identify novel cellular and molecular mechanisms of hGC migration and could potentially be used for in vitro drug efficacy testing.

Here we present an ex-vivo mixed monolayer culture system for the study of human glioma cell (hGC) migration in real-time. This model provides the ability to observe interactions between hGCs and both myelinated and non-myelinated axons within a compartmentalized chamber.

Glioblastoma is one of the most aggressive human cancers due to extensive cellular heterogeneity and the migration properties of hGCs. In order to better ...

A Rapid Screening Workflow to Identify Potential Combination Therapy for GBM using Patient-Derived Glioma Stem Cells

The glioma stem cells (GSCs) are a small fraction of cancer cells which play essential roles in tumor initiation, angiogenesis, and drug resistance in glioblastoma (GBM), the most prevalent and devastating primary brain tumor. The presence of GSCs makes the GBM very refractory to most of individual targeted agents, so high-throughput screening methods are required to identify potential effective combination therapeutics. The protocol describes a simple workflow to enable rapid screening for potential combination therapy with synergistic interaction. The general steps of this workflow consist of establishing luciferase-tagged GSCs, preparing matrigel coated plates, combination drug screening, analyzing, and validating the results.

The glioma stem cells (GSCs) are a small fraction of cancer cells which play essential roles in tumor initiation, angiogenesis, and drug resistance in ...

Co-culture of Glutamatergic Neurons and Pediatric High-Grade Glioma Cells Into Microfluidic Devices to Assess Electrical Interactions

Pediatric high-grade gliomas (pHGG) represent childhood and adolescent brain cancers that carry a rapid dismal prognosis. Since there is a need to overcome the resistance to current treatments and find a new way of cure, modeling the disease as close as possible in an in vitro setting to test new drugs and therapeutic procedures is highly demanding. Studying their fundamental pathobiological processes, including glutamatergic neuron hyperexcitability, will be a real advance in understanding interactions between the environmental brain and pHGG cells. Therefore, to recreate neurons/pHGG cell interactions, this work shows the development of a functional in vitro model co-culturing human-induced Pluripotent Stem (hiPS)-derived cortical glutamatergic neurons pHGG cells into compartmentalized microfluidic devices and a process to record their electrophysiological modifications. The first step was to differentiate and characterize human glutamatergic neurons. Secondly, the cells were cultured in microfluidic devices with pHGG derived cell lines. Brain microenvironment and neuronal activity were then included in this model to analyze the electrical impact of pHGG cells on these micro-environmental neurons. Electrophysiological recordings are coupled using multielectrode arrays (MEA) to these microfluidic devices to mimic physiological conditions and to record the electrical activity of the entire neural network. A significant increase in neuron excitability was underlined in the presence of tumor cells.

Recent works uncover the neuronal impact on high-grade pediatric glioma (pHGG) cells and their reciprocal interactions. The present work shows the development of an in vitro model co-culturing pHGG cells and glutamatergic neurons and recorded their electrophysiological interactions to mimic those interactivities.

Pediatric high-grade gliomas (pHGG) represent childhood and adolescent brain cancers that carry a rapid dismal prognosis. Since there is a need to ...

Live-3D-Cell Immunocytochemistry Assays of Pediatric Diffuse Midline Glioma

Cell migration and invasion are specific hallmarks of Diffuse Midline Glioma (DMG) H3K27M-mutant tumors. We have already modeled these features using three-dimensional (3D) cell-based invasion and migration assays. In this study, we have optimized these 3D assays for live-cell immunocytochemistry. An Antibody Labeling Reagent was used to detect in real-time the expression of the adhesion molecule CD44, on the plasma membrane of migrating and invading cells of a DMG H3K27M primary patient-derived cell line. CD44 is associated with cancer stem cell phenotype and tumor cell migration and invasion and is involved in the direct interactions with the central nervous system (CNS) extracellular matrix. Neurospheres (NS) from the DMG H3K27M cell line were embedded into the basal membrane matrix (BMM) or placed onto a thin coating layer of BMM, in the presence of an anti-CD44 antibody in conjunction with the antibody labeling reagent (ALR). The live-3D-cell immunocytochemistry image analysis was performed on a live-cell analysis instrument to quantitatively measure the overall CD44 expression, specifically on the migrating and invading cells. The method also allows visualizing in real-time the intermittent expression of CD44 on the plasma membrane of migrating and invading cells. Moreover, the assay also provided new insights into the potential role of CD44 in the mesenchymal to amoeboid transition in DMG H3K27M cells.

This study presents a protocol of live-3D-cell immunocytochemistry applied to a pediatric diffuse midline glioma cell line, useful to study in real-time the expression of proteins on the plasma membrane during dynamic processes like 3D cell invasion and migration.

Cell migration and invasion are specific hallmarks of Diffuse Midline Glioma (DMG) H3K27M-mutant tumors. We have already modeled these features using ...

Digital Spatial Profiling for Characterization of the Microenvironment in Adult-Type Diffusely Infiltrating Glioma

Diffusely infiltrating gliomas are associated with high morbidity and mortality due to the infiltrative nature of tumor spread. They are morphologically complex tumors, with a high degree of proteomic variability across both the tumor itself and its heterogenous microenvironment. The malignant potential of these tumors is enhanced by the dysregulation of proteins involved in several key pathways, including processes that maintain cellular stability and preserve the structural integrity of the microenvironment. Although there have been numerous bulk and single-cell glioma analyses, there is a relative paucity of spatial stratification of these proteomic data. Understanding differences in spatial distribution of tumorigenic factors and immune cell populations between the intrinsic tumor, invasive edge, and microenvironment offers valuable insight into the mechanisms underlying tumor proliferation and propagation. Digital spatial profiling (DSP) represents a powerful technology that can form the foundation for these important multilayer analyses.
DSP is a method that efficiently quantifies protein expression within user-specified spatial regions in a tissue specimen. DSP is ideal for studying the differential expression of multiple proteins within and across regions of distinction, enabling multiple levels of quantitative and qualitative analysis. The DSP protocol is systematic and user-friendly, allowing for customized spatial analysis of proteomic data. In this experiment, tissue microarrays are constructed from archived glioblastoma core biopsies. Next, a panel of antibodies is selected, targeting proteins of interest within the sample. The antibodies, which are preconjugated to UV-photocleavable DNA oligonucleotides, are then incubated with the tissue sample overnight. Under fluorescence microscopy visualization of the antibodies, regions of interest (ROIs) within which to quantify protein expression are defined with the samples. UV light is then directed at each ROI, cleaving the DNA oligonucleotides. The oligonucleotides are microaspirated and counted within each ROI, quantifying the corresponding protein on a spatial basis.

Proteomic dysregulation plays an important role in the spread of diffusely infiltrating gliomas, but several relevant proteins remain unidentified. Digital spatial processing (DSP) offers an efficient, high-throughput approach for characterizing the differential expression of candidate proteins that may contribute to the invasion and migration of infiltrative gliomas.

Diffusely infiltrating gliomas are associated with high morbidity and mortality due to the infiltrative nature of tumor spread. They are morphologically ...

Deciphering Tumor Microenvironment Using mIHC in Lung Squamous Carcinoma

Multiplex Immunohistochemistry Staining for Paraffin-embedded Lung Cancer Tissue

Lung cancer is the leading cause of malignant tumor-related morbidity and mortality all over the world, and the complex tumor microenvironment has been considered the leading cause of death in lung cancer patients. The complexity of the tumor microenvironment requires effective methods to understand cell-to-cell relationships in tumor tissues. The multiplex immunohistochemistry (mIHC) technique has become a key tool for inferring the relationship between the expression of proteins upstream and downstream of signaling pathways in tumor tissues and developing clinical diagnoses and treatment plans. mIHC is a multi-label immunofluorescence staining method based on Tyramine Signal Amplification (TSA) technology, which can simultaneously detect multiple target molecules on the same tissue section sample to achieve different protein co-expression and co-localization analysis. In this experimental protocol, paraffin-embedded tissue sections of lung squamous carcinoma of clinical origin were subjected to multiplex immunohistochemical staining. By optimizing the experimental protocol, multiplex immunohistochemical staining of labeled target cells and proteins was achieved, solving the problem of autofluorescence and channel crosstalk in lung tissues. In addition, multiplex immunohistochemical staining is widely used in the experimental validation of tumor-related, high-throughput sequencing, including single-cell sequencing, proteomics, and tissue space sequencing, providing intuitive and visual pathology validation results.

Author Spotlight: Enhancing Multicolor Fluorescence Localization in Lung Carcinoma Sample

This experimental protocol describes and optimizes a multiplex immunohistochemistry (IHC) staining method, mainly by optimizing single-channel antibody incubation conditions and adjusting the settings of antibodies and channels to solve the problems of autofluorescence and channel crosstalk in lung cancer tissues of clinical origin.

Lung cancer is the leading cause of malignant tumor-related morbidity and mortality all over the world, and the complex tumor microenvironment has been ...