This work was supported by The Fox Chase Cancer Center Board of Directors (DDM), the American Society of Hematology Scholar Award (SMS), American Cancer Society RSG (SMS) and the Department of Defense (Award#: W81XWH-18-1-0472).

All of the animal procedures described in this protocol have been approved by the Institutional Animal Care and Use committee (IACUC) at Fox Chase Cancer Center.
NOTE: The protocol workflow is divided into 4 parts as presented in Figure 1 and the required reagents are listed in the Table of Materials.
1. Bone Marrow (BM) Isolation
NOTE: MLL-AF9 leukemia mice were generated as described previously11.
<ol>
	<li>Recover mono-nuclear bone marrow cells, as described previously12,13,14,15, from wild type C57.Bl6 mice (which express the CD45.2 congenic marker) as well as from C57.Bl6-SJL mice ( which express the CD45.1 congenic marker) that have been transplanted with MLL-AF9-expressing leukemia cells (CD45.2+). 
	NOTE: BM can be recovered from mice either by crushing12,13 or by flushing bones14,15. For the experiments presented here, BM was recovered from both healthy and leukemia mice via flushing.</li>
</ol>
2. Mitochondrial ROS Fluorogenic Dye Staining
<ol>
	<li>Once mono-nuclear bone marrow cells have been recovered from healthy and/or leukemia mice, stain an aliquot of cells with Trypan Blue and count using a hemocytometer to determine the starting number of total BM cells.</li>
	<li>Centrifuge the cells at 300 x g for 5 min. Aspirate the supernatant and resuspend the pellet in F-PBS (PBS supplemented with 2% fetal bovine serum and a 1% Penicillin/Streptomycin cocktail) to a concentration of 2 x 106 cells/mL.</li>
	<li>Aliquot 200 &#181;L of cell suspension per tube into 9 single-color control tubes labeled as follows: 
	No stain, B220-Cy5-PE, cKit-Cy7-APC, Sca1-PacBlue, CD150-APC (for healthy HSPCs only), CD45.2-APC (for leukemia cells only), CD34-FITC, Mitochondrial ROS dye and Live/dead cell stain. 
	NOTE:&#160;(Optional) A positive control for the induction of mitochondrial ROS can be prepared by treating 2 x 105 cells in 200 &#181;L with 20 &#181;M of Menadione Sodium Bisulfite (MSB) for 1 h at 37 &#730;C in a 5% CO2 incubator. A second control to reverse the MSB-mediated induction of mitochondrial ROS can be prepared by treating 2 x 105 cells in 200 &#181;L with 20 &#181;M of MSB plus 100 &#181;M N-acetyl-L-cysteine (NAC) for 1 h at 37 &#730;C in a 5% CO2 incubator.</li>
	<li>Aliquot the remaining cells in a tube (experimental tube) and centrifuge at 300 x g for 5 min.</li>
	<li>Resuspend the cells in F-PBS with a live/dead cell stain according to the manufacturer&#8217;s instructions. Incubate on ice for 30 min. Be sure to add live/dead stain to the single-color control tube.</li>
	<li>Add 1.0 mL of room temperature (RT) F-PBS to both single-color and experimental tubes stained with the live/dead dye. Centrifuge 5 min at 300 x g at RT.</li>
	<li>Resuspend 50 &#181;g of the mitochondrial ROS dye in 13 &#181;L of dimethyl sulfoxide (DMSO) to obtain a 5 mM stock solution.</li>
	<li>Dilute mitochondrial ROS dye to a final concentration of 5 &#181;M in RT F-PBS with or without Verapamil (50 &#181;M).</li>
	<li>Aspirate off the wash of the live/dead cell stain. Add 200 &#181;L of mitochondrial ROS dye stain containing Verapamil to each experimental tube as well as the mitochondrial ROS dye single-color control tube.</li>
	<li>Vortex to mix and incubate for 10 min at 37 &#730;C in the dark.</li>
	<li>Add 1.0 mL of RT F-PBS to the mitochondrial ROS-stained single-color control and experimental tubes. Centrifuge 5 min at 300 x g at RT.</li>
	<li>Aspirate off the supernatant and wash the cells with an additional 1.0 mL of RT F-PBS. Centrifuge 5 min at 300 x g at RT.</li>
</ol>
3. Lineage Antibody Staining
<ol>
	<li>Prepare the antibody cocktails listed in Table 1. 
	NOTE: These antibodies cocktails have been optimized previously14,15,16.</li>
	<li>Aspirate the supernatant from the final mitochondrial ROS dye wash of the experimental tubes containing healthy BM and add 200 &#181;L of antibody cocktail #1 to each tube. Vortex to mix. Also prepare the single-color control tubes. Incubate for 60 min on ice in the dark.</li>
	<li>Aspirate the supernatant from the final mitochondrial ROS dye wash of the experimental tubes containing leukemia BM and add 200 &#181;L of the antibody cocktail #2 to each tube. Vortex to mix. Incubate for 60 min on ice in the dark.</li>
	<li>Wash with 1.0 mL of cold F-PBS and centrifuge 5 min at 300 x g at RT.</li>
	<li>Resuspend cells in 500 &#181;L of cold F-PBS and filter the cells in a flow cytometer tube using a 40 &#181;m filter to exclude aggregates.</li>
</ol>
4. Flow Cytometry Acquisition and Analysis
NOTE: Several hematopoietic stem and progenitor subsets are rare, such as long-term hematopoietic stem cells. Thus, ideally 3-5 million events should be collected for each experimental tube during flow cytometry acquisition for sufficient analysis of mitochondrial ROS in the various HSPC subsets.
<ol>
	<li>Use the no-stain control tube to set the forward (FSC-A) and side (SSC-A) scatter plots based on the size and complexity of the cell population analyzed.</li>
	<li>Use the no-stain and single-color control tubes to compensate the flow cytometer.</li>
	<li>Gate out extraneous debris from the forward and side scatter plot (Figure 2A,B, first panel from the left).</li>
	<li>Gate out doublets using a double discriminator such as the forward discriminator (Figure 2A,B, second panel from the left).</li>
	<li>Follow the gating strategy proposed in Figure 2A,B to select live cells, lineage low cells and the various HSPC and leukemia subsets.</li>
	<li>For each population of interest, analyze the median fluorescence intensity (MFI) of the TRPE channel (x-axis) in a histogram plot to evaluate differences in the mitochondrial ROS signal (Figure 3A-C, left panels). Levels of mitochondrial ROS can be evaluated at the single-cell level by comparing mitochondrial ROS staining versus specific lineage markers in a scatter plot.</li>
</ol>

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The authors have nothing to disclose.

Fluorogenic dyes that have been developed for the detection of ROS are frequently evaluated in fixed cells by microscopy or in live cells by flow cytometry22. Flow cytometric evaluation of mitochondrial ROS in BM cells using mitochondrial ROS fluorogenic dyes has two major advantages: 1) It is a fast and simple technique that is suitable for live cell analysis and 2) it allows for distinguishing and analyzing rare populations at the single-cell level in the BM using surface marker staining. The st...

Reactive Oxygen Species (ROS) are highly reactive molecules derived from molecular oxygen. The most well-defined cellular location of ROS production is the mitochondria, where electrons that pass through the electron transport chain (ETC) during oxidative phosphorylation (OXPHOS) are absorbed by molecular oxygen leading to the formation of a specific type of ROS called superoxides1. Through the actions of a series of enzymes, called superoxide dismutases or SODs, superoxides are converted into hydrogen peroxides, which are subsequently neutralized into water by enzymes such as catalase or glutathione peroxidases (GPX). Perturbations in ROS-regulatory mechanisms can lead to the excess production of ROS, often referred to as oxidative stress, which have harmful and potentially lethal cellular consequences such as macromolecule damage (i.e., DNA, protein, lipids). Moreover, oxidative stress is related to several pathologies, such as diabetes, inflammatory diseases, aging and tumors2,3,4. To maintain redox homeostasis and prevent oxidative stress, cells possess a variety of ROS-regulating mechanisms5.
Physiological levels of certain ROS are necessary for proper embryonic and adult hematopoiesis6. However, excess ROS is associated with DNA damage, cellular differentiation and exhaustion of the hematopoietic stem and progenitor pool. There is also evidence that alterations in redox biology may differ between leukemia and healthy cells. For example, ROS levels tend to be higher in acute myeloid leukemia (AML) cells relative to their healthy counterparts and other studies have suggested that leukemia stem cells maintain a low steady-state level of ROS for survival7,8. Importantly, strategies for therapeutically capitalizing on these redox differences have shown promise in several human cancer settings9,10. Therefore, assays that allow for the assessment of ROS levels in mouse models may improve our understanding of how these species contribute to cellular physiology and disease pathogenesis as well as potentially provide a platform for assessing the effectiveness of novel redox-targeting anti-cancer therapies.

<table border="0" cellpadding="0" cellspacing="0" style="width:1109px;" width="1110">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:247px;">Heat inactivated FBS</td>
			<td style="width:279px;">VWR Seradigm LIFE SCIENCE</td>
			<td style="width:393px;">97068-085</td>
			<td style="width:191px;">Media</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Penicillin Streptomycin</td>
			<td>Corning</td>
			<td>30-002-CI</td>
			<td>Media</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">PBS</td>
			<td>Fisher Scientific</td>
			<td>BP399-20</td>
			<td>Buffer</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">15 mL conical tube</td>
			<td>BD falcon</td>
			<td>352096</td>
			<td>Tissue Culture Supplies</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">50 mL conical tube</td>
			<td>BD falcon</td>
			<td>352098</td>
			<td>Tissue Culture Supplies</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">40 &#956;m cell strainers</td>
			<td>Fisher Scientific</td>
			<td>22-363-547</td>
			<td>Tissue Culture Supplies</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">RBC Lysis Buffer</td>
			<td>Fisher Scientific</td>
			<td>50-112-9751</td>
			<td>Tissue Culture Supplies</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Menadione sodium Bisulfite</td>
			<td>Sigma aldrich</td>
			<td>M5750</td>
			<td>Pro-oxidant</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">NAC</td>
			<td>Sigma aldrich</td>
			<td>A7250</td>
			<td>Anti-oxidant</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">CD3 PE-Cy5 clone 145-2c11</td>
			<td>Biolegend</td>
			<td>100310</td>
			<td>Antibody</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">CD4 PE-Cy5 clone RM4-5</td>
			<td>eBioscience</td>
			<td>15-0041-81</td>
			<td>Antibody</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">CD8 PE-Cy5 clone 53-6.7</td>
			<td>eBioscience</td>
			<td>15-0081-81</td>
			<td>Antibody</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">CD19 PE-Cy5 clone 6D5</td>
			<td>Biolegend</td>
			<td>115510</td>
			<td>Antibody</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">B220 PE-Cy5 clone RA3-6B2</td>
			<td>Biolegend</td>
			<td>103210</td>
			<td>Antibody</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Gr1 PE-Cy5 clone RB6-8C5</td>
			<td>Biolegend</td>
			<td>108410</td>
			<td>Antibody</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Ter119 PE-Cy5 clone Ter-119</td>
			<td>Biolegend</td>
			<td>116210</td>
			<td>Antibody</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">CD48 PE-Cy5 clone HM48-1</td>
			<td>Biolegend</td>
			<td>103420</td>
			<td>Antibody</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">CD117&#160; APC-Cy7 clone 2B8</td>
			<td>Biolegend</td>
			<td>105825</td>
			<td>Antibody</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Sca1 peacific Blue clone D7</td>
			<td>Biolegend</td>
			<td>108120</td>
			<td>Antibody</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">CD150 APC clone TC15-12F12.2</td>
			<td>Biolegend</td>
			<td>115909</td>
			<td>Antibody</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">CD34 FITC clone RAM34</td>
			<td>BD Bioscience</td>
			<td>553733</td>
			<td>Antibody</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">CD45.2 APC clone 104</td>
			<td>Biolegend</td>
			<td>1098313</td>
			<td>Antibody</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">MitoSOX Red</td>
			<td>ThermoFisher Scientific</td>
			<td>M36008</td>
			<td>Dye</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Mitotracker Green</td>
			<td>ThermoFisher Scientific</td>
			<td>M7514</td>
			<td>Dye</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Live/dead Yellow Dye</td>
			<td>ThermoFisher Scientific</td>
			<td>L34967</td>
			<td>Dye</td>
		</tr>
	</tbody>
</table>

flow cytometric analysis of mitochondrial reactive oxygen species in murine hematopoietic stem and progenitor cells and mll-af9 driven leukemia

We present a flow cytometric approach for analyzing mitochondrial ROS in various live bone marrow (BM)-derived stem and progenitor cell populations from healthy mice as well as mice with AML driven by MLL-AF9. Specifically, we describe a two-step cell staining process, whereby healthy or leukemia BM cells are first stained with a fluorogenic dye that detects mitochondrial superoxides, followed by staining with fluorochrome-linked monoclonal antibodies that are used to distinguish various healthy and malignant hematopoietic progenitor populations. We also provide a strategy for acquiring and analyzing the samples by flow cytometry. The entire protocol can be carried out in a timeframe as short as 3-4 h. We also highlight the key variables to consider as well as the advantages and limitations of monitoring ROS production in the mitochondrial compartment of live hematopoietic and leukemia stem and progenitor subpopulations using fluorogenic dyes by flow cytometry. Furthermore, we present data that mitochondrial ROS abundance varies among distinct healthy HSPC sub-populations and leukemia progenitors and discuss the possible applications of this technique in hematologic research.

Presented is a method for analyzing ROS in the mitochondria of multiple healthy and MLL-AF9-expressing leukemia progenitor populations. Figure 1 displays a schematic view of the protocol workflow, which consists of 4 major steps: 1) BM isolation from mice; 2) Staining BM cells with a fluorogenic dye that recognizes mitochondrial ROS, particularly superoxides; 3) Surface marker antibody staining to delineate various healthy and leukemia hematopoietic populations; and 4) Flow cytometry acquisi...

Watch this Scientific Journal Video about Flow Cytometric Analysis of Mitochondrial Reactive Oxygen Species in Murine Hematopoietic Stem and Progenitor Cells and MLL-AF9 Driven Leukemia at JoVE.com

Flow Cytometric Analysis of Mitochondrial Reactive Oxygen Species in Murine Hematopoietic Stem and Progenitor Cells and MLL-AF9 Driven Leukemia

We describe a method for using multiparameter flow cytometry to detect mitochondrial reactive oxygen species (ROS) in murine healthy hematopoietic stem and progenitor cells (HSPCs) and leukemia cells from a mouse model of acute myeloid leukemia (AML) driven by MLL-AF9.

We present a flow cytometric approach for analyzing mitochondrial ROS in various live bone marrow (BM)-derived stem and progenitor cell populations from ...

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Cancer Research

7.2K Views.  Fox Chase Cancer Center. We describe a method for using multiparameter flow cytometry to detect mitochondrial reactive oxygen species (ROS) in murine healthy hematopoietic stem and progenitor cells (HSPCs) and leukemia cells from a mouse model of acute myeloid leukemia (AML) driven by MLL-AF9.

Video: Flow Cytometric Analysis of Mitochondrial Reactive Oxygen Species in Murine Hematopoietic Stem and Progenitor Cells and MLL-AF9 Driven Leukemia

Comprehensive Protocol to Sample and Process Bone Marrow for Measuring Measurable Residual Disease and Leukemic Stem Cells in Acute Myeloid Leukemia

Response criteria in acute myeloid leukemia (AML) has recently been re-established, with morphologic examination utilized to determine whether patients have achieved complete remission (CR). Approximately half of the adult patients who entered CR will relapse within 12 months due to the outgrowth of residual AML cells in the bone marrow. The quantitation of these remaining leukemia cells, known as minimal or measurable residual disease (MRD), can be a robust biomarker for the prediction of these relapses. Moreover, retrospective analysis of several studies has shown that the presence of MRD in the bone marrow of AML patients correlates with poor survival. Not only is the total leukemic population, reflected by cells harboring a leukemia associated immune-phenotype (LAIP), associated with clinical outcome, but so is the immature low frequency subpopulation of leukemia stem cells (LSC), both of which can be monitored through flow cytometry MRD or MRD-like approaches. The availability of sensitive assays that enable detection of residual leukemia (stem) cells on the basis of disease-specific or disease-associated features (abnormal molecular markers or aberrant immunophenotypes) have drastically improved MRD assessment in AML. However, given the inherent heterogeneity and complexity of AML as a disease, methods for sampling bone marrow and performing MRD and LSC analysis should be harmonized when possible. In this manuscript we describe a detailed methodology for adequate bone marrow aspirate sampling, transport, sample processing for optimal multi-color flow cytometry assessment, and gating strategies to assess MRD and LSC to aid in therapeutic decision making for AML patients.

Detection of minimal or measurable residual disease (MRD) is an important prognostic biomarker for refining risk assessment and predicting relapse in acute myeloid leukemia (AML). These comprehensive guidelines and recommendations with best practices for consistent and accurate identification and detection of MRD, may aid in making effective AML treatment decisions.

Response criteria in acute myeloid leukemia (AML) has recently been re-established, with morphologic examination utilized to determine whether patients ...

Flow Cytometry to Estimate Leukemia Stem Cells in Primary Acute Myeloid Leukemia and in Patient-derived-xenografts, at Diagnosis and Follow Up

Acute myeloid leukemia (AML) is a heterogeneous, and if not treated, fatal disease. It is the most common cause of leukemia-associated mortality in adults. Initially, AML is a disease of hematopoietic stem cells (HSC) characterized by arrest of differentiation, subsequent accumulation of leukemia blast cells, and reduced production of functional hematopoietic elements. Heterogeneity extends to the presence of leukemia stem cells (LSC), with this dynamic cell compartment evolving to overcome various selection pressures imposed upon during leukemia progression and treatment. To further define the LSC population, the addition of CD90 and CD45RA allows the discrimination of normal HSCs and multipotent progenitors within the CD34+CD38- cell compartment. Here, we outline a protocol to detect simultaneous expression of several putative LSC markers (CD34, CD38, CD45RA, CD90) on primary blast cells of human AML by multiparametric flow cytometry. Furthermore, we show how to quantify three progenitor populations and a putative LSC population with increasing degree of maturation. We confirmed the presence of these populations in corresponding patient-derived-xenografts. This method of detection and quantification of putative LSC may be used for clinical follow-up of chemotherapy response (i.e., minimal residual disease), as residual LSC may cause AML relapse.

We outline a protocol to detect simultaneous expression of leukemia stem cell markers on primary acute myeloid leukemia cells by flow cytometry. We show how to quantify three progenitor populations and a putative LSC population with increasing degree of maturation. We confirmed the presence of these populations in corresponding patient-derived-xenografts.

Acute myeloid leukemia (AML) is a heterogeneous, and if not treated, fatal disease. It is the most common cause of leukemia-associated mortality in ...

Assessment of the Metabolic Profile of Primary Leukemia Cells

The metabolic requirement of cancer cells can negatively influence survival and treatment efficacy. Nowadays, pharmaceutical targeting of metabolic pathways is tested in many types of tumors. Thus, characterization of cancer cell metabolic setup is inevitable in order to target the correct pathway to improve the overall outcome of patients. Unfortunately, in a majority of cancers, the malignant cells are quite difficult to obtain in higher numbers and the tissue biopsy is required. Leukemia is an exception, where a sufficient number of leukemic cells can be isolated from the bone marrow. Here, we provide a detailed protocol for the isolation of leukemic cells from leukemia patients bone marrow and subsequent analysis of their metabolic state using extracellular flux analyzer. Leukemic cells are isolated by the density gradient, which does not affect their viability. The next cultivation step helps them to regenerate, thus the metabolic state measured is the state of cells in optimal conditions. This protocol allows achieving consistent, well-standardized results, which could be used for the personalized therapy.

Here we present a protocol for the isolation of leukemic cells from leukemia patients bone marrow and analysis of their metabolic state. Assessment of the metabolic profile of primary leukemia cells could help to better characterize the demand of primary cells and could lead up to more personalized medicine.

The metabolic requirement of cancer cells can negatively influence survival and treatment efficacy. Nowadays, pharmaceutical targeting of metabolic ...

Flow Cytometric Detection of Newly-formed Breast Cancer Stem Cell-like Cells After Apoptosis Reversal

Cancer recurrence has long been studied by oncologists while the underlying mechanisms remain unclear. Recently, we and others found that a phenomenon named apoptosis reversal leads to increased tumorigenicity in various cell models under different stimuli. Previous studies have been focused on tracking this process in vitro and in vivo; however, the isolation of real reversed cells has yet to be achieved, which limits our understanding on the consequences of apoptosis reversal. Here, we take advantage of a Caspase-3/7 Green Detection dye to label cells with activated caspases after apoptotic induction. Cells with positive signals are further sorted out by fluorescence-activated cell sorting (FACS) for recovery. Morphological examination under confocal microscopy helps confirm the apoptotic status before FACS. An increase in tumorigenicity can often be attributed to the elevation in the percentage of cancer stem cell (CSC)-like cells. Also, given the heterogeneity of breast cancer, identifying the origin of these CSC-like cells would be critical to cancer treatment. Thus, we prepare breast non-stem cancer cells before triggering apoptosis, isolating caspase-activated cells and performing the apoptosis reversal procedure. Flow cytometry analysis reveals that breast CSC-like cells re-appear in the reversed group, indicating breast CSC-like cells are transited from breast non-stem cancer cells during apoptosis reversal. In summary, this protocol includes the isolation of apoptotic breast cancer cells and detection of changes in CSC percentage in reversed cells by flow cytometry.

Here, we present a protocol to isolate apoptotic breast cancer cells by fluorescence-activated cell sorting and further detect the transition of breast non-stem cancer cells to breast cancer stem cell-like cells after apoptosis reversal by flow cytometry.

Cancer recurrence has long been studied by oncologists while the underlying mechanisms remain unclear. Recently, we and others found that a phenomenon ...

Evaluating Cell Death Using Cell-Free Supernatant of Probiotics in Three-Dimensional Spheroid Cultures of Colorectal Cancer Cells

This manuscript describes a protocol to evaluate cancer cell deaths in three dimensional (3D) spheroids of multicellular types of cancer cells using supernatants from Lactobacillus fermentum cell culture, considered as probiotics cultures. The use of 3D cultures to test Lactobacillus cell-free supernatant (LCFS) are a better option than testing in 2D monolayers, especially as L. fermentum can produce anti-cancer effects within the gut. L. fermentum supernatant was identified to possess increased anti-proliferative effects against several colorectal cancer (CRC) cells in 3D culture conditions. Interestingly, these effects were strongly related to the culture model, demonstrating the notable ability of L. fermentum to induce cancer cell death. Stable spheroids were generated from diverse CRCs (colorectal cancer cells) using the protocol presented below. This protocol of generating 3D spheroid is time saving and cost effective. This system was developed to easily investigate the anti-cancer effects of LCFS in multiple types of CRC spheroids. As expected, CRC spheroids treated with LCFS strongly induced cell death during the experiment and expressed specific apoptosis molecular markers as analyzed by qRT-PCR, western blotting, and FACS analysis. Therefore, this method is valuable for exploring cell viability and evaluating the efficacy of anti-cancer drugs.

Here methods are presented to understand anti-cancer effects of Lactobacillus cell-free supernatant (LCFS). Colorectal cancer cell lines show cell deaths when treated with LCFS in 3D cultures. The process of generating spheroids can be optimized depending on the scaffold and the analysis methods presented are useful for evaluating the involved signaling pathways.

This manuscript describes a protocol to evaluate cancer cell deaths in three dimensional (3D) spheroids of multicellular types of cancer cells using ...

Two Flow Cytometric Approaches of NKG2D Ligand Surface Detection to Distinguish Stem Cells from Bulk Subpopulations in Acute Myeloid Leukemia

Within the same patient, absence of NKG2D ligands (NKG2DL) surface expression was shown to distinguish leukemic subpopulations with stem cell properties (so called leukemic stem cells, LSCs) from more differentiated counterpart leukemic cells that lack disease initiation potential although they carry similar leukemia specific genetic mutations. NKG2DL are biochemically highly diverse MHC class I-like self-molecules. Healthy cells in homeostatic conditions generally do not express NKG2DL on the cell surface. Instead, expression of these ligands is induced upon exposure to cellular stress (e.g., oncogenic transformation or infectious stimuli) to trigger elimination of damaged cells via lysis through NKG2D-receptor-expressing immune cells such as natural killer (NK) cells. Interestingly, NKG2DL surface expression is selectively suppressed in LSC subpopulations, allowing these cells to evade NKG2D-mediated immune surveillance. Here, we present a side-by-side analysis of two different flow cytometry methods that allow the investigation of NKG2DL surface expression on cancer cells i.e., a method involving pan-ligand recognition and a method involving staining with multiple antibodies against single ligands. These methods can be used to separate viable NKG2DL negative cellular subpopulations with putative cancer stem cell properties from NKG2DL positive non-LSC.

We present two different staining protocols for NKG2D ligand (NKG2DL) detection in human primary acute myeloid leukemia (AML) samples. The first approach is based on a fusion protein, able to recognize all known and potentially yet unknown ligands, while the second protocol relies on the addition of multiple anti-NKG2DL antibodies.

Within the same patient, absence of NKG2D ligands (NKG2DL) surface expression was shown to distinguish leukemic subpopulations with stem cell properties ...

Flow Cytometric Analysis of Apoptotic Biomarkers in Actinomycin D-Treated SiHa Cervical Cancer Cells

Apoptosis biomarkers were investigated in actinomycin D-treated SiHa cervical cancer cells using a benchtop flow cytometer. Early biomarkers (Annexin V and mitochondrial membrane potential) and late biomarkers (caspases 3 and 7, and DNA damage) of apoptosis were measured in experimental and control cultures. Cultures were incubated for 24 hours in a humidified incubator at 37 &#176;C with 5% CO2. The cells were then detached using trypsin and enumerated using a flow cytometric cell count assay. Cells were further analyzed for apoptosis using an Annexin V assay, a mitochondrial electrochemical transmembrane potential assay, a caspase 3/7 assay, and a DNA damage assay. This article provides an overview of apoptosis and traditional flow cytometry, and elaborates flow cytometric protocols for processing and analyzing SiHa cells. The results describe positive, negative, and sub-optimal experimental data. Also discussed are interpretation and caveats in performing flow cytometric analysis of apoptosis using this analytical platform. Flow cytometric analysis provides an accurate measurement of early and late biomarkers for apoptosis.

Apoptosis can be characterized by flow cytometric analysis of early and late apoptotic biomarkers. The cervical cancer cell line, SiHa, was analyzed for apoptosis biomarkers after treatment with Actinomycin D using a benchtop flow cytometer.

Apoptosis biomarkers were investigated in actinomycin D-treated SiHa cervical cancer cells using a benchtop flow cytometer. Early biomarkers (Annexin V ...

Orthotopic Implantation of Patient-Derived Cancer Cells in Mice Recapitulates Advanced Colorectal Cancer

Over the last decade, more sophisticated preclinical colorectal cancer (CRC) models have been established using patient-derived cancer cells and 3D tumoroids. Since patient derived tumor organoids can retain the characteristics of the original tumor, these reliable preclinical models enable cancer drug screening and the study of drug resistance mechanisms. However, CRC related death in patients is mostly associated with the presence of metastatic disease. It is therefore essential to evaluate the efficacy of anti-cancer therapies in relevant in vivo models that truly recapitulate the key molecular features of human cancer metastasis. We have established an orthotopic model based on the injection of CRC patient-derived cancer cells directly into the cecum wall of mice. These tumor cells develop primary tumors in the cecum that metastasize to the liver and lungs, which is frequently observed in patients with advanced CRC. This CRC mouse model can be used to evaluate drug responses monitored by microcomputed tomography (&#181;CT), a clinically relevant small-scale imaging method that can easily identify primary tumors or metastases in patients. Here, we describe the surgical procedure and the required methodology to implant patient-derived cancer cells in the cecum wall of immunodeficient mice.

This protocol describes the orthotopic implantation of patient-derived cancer cells in the cecum wall of immunodeficient mice. The model recapitulates advanced colorectal cancer metastatic disease and allows for the evaluation of new therapeutic drugs in a clinically relevant scenario of lung and liver metastases.

Over the last decade, more sophisticated preclinical colorectal cancer (CRC) models have been established using patient-derived cancer cells and 3D ...

Engineering Oncogenic Heterozygous Gain-of-Function Mutations in Human Hematopoietic Stem and Progenitor Cells

Throughout their lifetime, hematopoietic stem and progenitor cells (HSPCs) acquire somatic mutations. Some of these mutations alter HSPC functional properties such as proliferation and differentiation, thereby promoting the development of hematologic malignancies. Efficient and precise genetic manipulation of HSPCs is required to model, characterize, and better understand the functional consequences of recurrent somatic mutations. Mutations can have a deleterious effect on a gene and result in loss-of-function (LOF) or, in stark contrast, may enhance function or even lead to novel characteristics of a particular gene, termed gain-of-function (GOF). In contrast to LOF mutations, GOF mutations almost exclusively occur in a heterozygous fashion. Current genome-editing protocols do not allow for the selective targeting of individual alleles, hampering the ability to model heterozygous GOF mutations. Here, we provide a detailed protocol on how to engineer heterozygous GOF hotspot mutations in human HSPCs by combining CRISPR/Cas9-mediated homology-directed repair and recombinant AAV6 technology for efficient DNA donor template transfer. Importantly, this strategy makes use of a dual fluorescent reporter system to allow for the tracking and purification of successfully heterozygously edited HSPCs. This strategy can be employed to precisely investigate how GOF mutations affect HSPC function and their progression toward hematological malignancies.

Novel strategies to faithfully model somatic mutations in hematopoietic stem and progenitor cells (HSPCs) are necessary to better study hematopoietic stem cell biology and hematological malignancies. Here, a protocol to model heterozygous gain-of-function mutations in HSPCs by combining the use of CRISPR/Cas9 and dual rAAV donor transduction is described.

Throughout their lifetime, hematopoietic stem and progenitor cells (HSPCs) acquire somatic mutations. Some of these mutations alter HSPC functional ...

Co-Culture and Transduction of Murine Thymocytes on Delta-Like 4-Expressing Stromal Cells to Study Oncogenes in T-Cell Leukemia

Transduced mouse immature thymocytes can be differentiated into T cells&#160;in vitro&#160;using the delta-like 4-expressing bone marrow stromal cell line co-culture system (OP9-DL4). As retroviral transduction requires dividing cells for transgene integration, OP9-DL4 provides a suitable in vitro environment for cultivating hematopoietic progenitor cells. This is particularly advantageous when studying the effects of the expression of a specific gene during normal T cell development and leukemogenesis, as it allows researchers to circumvent the time-consuming process of generating transgenic mice. To achieve successful outcomes, a series of coordinated steps involving the simultaneous manipulation of different types of cells must be carefully performed. Although these are very well-established procedures, the lack of a common source in the literature often means a series of optimizations are required, which can be time-consuming. This protocol has been shown to be efficient in transducing primary thymocytes followed by differentiation on OP9-DL4 cells. Detailed here is a protocol that can serve as a quick and optimized guide for the co-culture of retrovirally transduced thymocytes on OP9-DL4 stromal cells.

This protocol describes the isolation of double-negative thymocytes from the mouse thymus followed by retroviral transduction and co-culture on the delta-like 4-expressing bone marrow stromal cell line co-culture system (OP9-DL4) for further functional analysis.

Transduced mouse immature thymocytes can be differentiated into T cells&#160;in vitro&#160;using the delta-like 4-expressing bone marrow stromal cell line ...