This work was supported by grants from the National Institute of Neurological Diseases and Stroke (R01 NS048353 and R01 NS109655 to S.L.C.; R01 NS109655-03S1 to D.P.J.), the National Cancer Institute (R01 CA122804 to S.L.C.) and the Department of Defense (X81XWH-09-1-0086 and W81XWH-12-1-0164 to S.L.C.).

Pathology Assessment of PN-MPNST Progression in the P0-GGFβ3 Mouse Model

<ol>
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The authors have no conflicts of interest to disclose.

The histological and biochemical methods presented here provide a framework for diagnosing and characterizing GEM models of neurofibroma and MPNST pathogenesis. Over the years, we have found these methodologies to be quite useful for assessing the pathology of peripheral nerve sheath tumors arising in GEM models21,25,26. However, while the protocols outlined here are useful for determining how accurately tumors in the GEM models...

Over the last three decades, numerous laboratories have attempted to create mouse models of human cancers by introducing human cancer-associated mutations into the mouse genome or by overexpressing a gene product that is overexpressed in human cancers. The resulting genetically engineered mouse (GEM) models can be used for a variety of purposes such as establishing that the newly introduced genomic modification initiates tumorigenesis, identifying other subsequently occurring genetic or epigenetic changes that contribute to tumor progression, and defining the key signaling pathways that drive tumor initiation and progression. Unlike orthotopic xenograft models, which rely on the use of immunodeficient mice, GEM cancer models have a fully functional immune system and so more accurately model responses to candidate therapeutic agents. However, when using GEM cancer models for purposes such as these, it is essential that investigators confirm that observations made with GEM neoplasms are relevant to their human counterparts. This validation should include a thorough assessment of the pathology of the GEM neoplasms and a determination as to whether the pathologic features of the GEM neoplasms recapitulate the pathology of the corresponding human tumor type.
The tumor susceptibility syndrome neurofibromatosis type 1 (NF1) is the most common genetic disease affecting the human nervous system, occurring in approximately 1 in every 3,000-3,500 live births1,2,3. Individuals afflicted with NF1 develop multiple benign peripheral nerve sheath tumors known as neurofibromas in their skin (dermal neurofibromas) and in large nerves and nerve plexuses (plexiform neurofibromas). While both dermal and plexiform neurofibromas worsen the patient&#39;s quality of life by producing physical, behavioral, and/or social impairment, plexiform neurofibromas (PNs) are particularly dangerous4,5.&#160;This is because PNs frequently transform into malignant peripheral nerve sheath tumors (MPNSTs), which are aggressive spindle cell neoplasms with an exceptionally low survival rate1,2. In large part, this low survival rate is because the radio- and chemotherapeutic regimens that are currently used to treat MPNSTs are ineffective. However, developing new, more effective therapies has been challenging. This is because, despite how commonly MPNSTs occur in NF1 patients, they are still rare neoplasms. As a result, it is very difficult to obtain large numbers of human tumors for study; it is also challenging to recruit enough patients with MPNSTs for clinical trials. To overcome these limitations, several GEM models have been generated with the goal of gaining further insights into the abnormalities driving neurofibroma pathogenesis and PN-MPNST progression and to facilitate preclinical trials with candidate therapeutic agents.
NF1 patients have inactivating mutations in one copy of the NF1 gene. Neurofibroma pathogenesis is triggered when an inactivating mutation in the remaining functional NF1 gene occurs in a cell in the Schwann cell lineage. Surprisingly, however, when mice were generated with germline inactivating Nf1 mutations, they did not develop neurofibromas6,7. The subsequent demonstration that mice with Nf1-null Schwann cells and Nf1 haploinsufficiency in all other cell types (Krox20-Cre;Nf1flox/- mice) developed plexiform neurofibromas suggested that reduced Nf1 gene dosage in additional cell types was required for neurofibroma pathogenesis8. Even then, the plexiform neurofibromas in Krox20-Cre;Nf1flox/- mice did not progress to become MPNSTs and so only partially mimicked the biology of their human counterparts. MPNST pathogenesis did occur when Nf1 mutations were partnered with mutations in additional tumor suppressor genes such as Trp539 or Cdkn2a10, but MPNSTs in these GEM models developed de novo or from atypical neurofibromatous neoplasms of uncertain biologic potential (ANNUBPs)11,12, rather than from preexisting benign plexiform neurofibromas (see13,14 for excellent reviews of these models as well as other models introducing additional MPNST-associated loss of function mutations in genes such as Suz12 and Pten15).
These mouse models have been invaluable for establishing the role that genes such as NF1, TP53, and CDKN2A play in the pathogenesis of NF1-associated peripheral nervous system neoplasms and for preclinical trials testing candidate therapeutic agents. However, we still have an incomplete understanding of the process by which plexiform neurofibromas progress to become atypical neurofibromatous neoplasms of uncertain biologic potential (ANNUBPs16) and then MPNSTs. Some progress has recently been made in understanding this process with the recent report that mice with deletions in Nf1 and Arf develop ANNUBPs that progress to become MPNSTs11. However, Nf1 mutation-based mouse models that fully recapitulate the process of plexiform neurofibroma-MPNST progression seen in humans do not yet exist. In addition, it is not clear whether there are multiple distinct pathways that lead to the development of MPNSTs. Given this, it is possible that the GEMs described above only model a subset of several different pathways that lead to neurofibroma-MPNST progression and MPNST pathogenesis. This point is emphasized by the fact that MPNSTs also occur sporadically and that some sporadic MPNSTs apparently do not have NF1 mutations17,18.
Although this latter point has been challenged by Magollon-Lorenz et al.&#39;s recent suggestion that at least some sporadic MPNSTs lacking NF1 mutations are melanomas or a different type of sarcoma19, we have recently reported a sporadic MPNST and a cell line derived from this tumor (2XSB cells) that was NF1 wild-type20. During the characterization of the parent tumor and the 2XSB cell line, we systematically ruled out alternative diagnostic possibilities, including melanoma and the multiple other sarcoma types that are routinely considered in the differential diagnosis of a sporadic malignant peripheral nerve sheath tumor20. In addition, we note that Magollon-Lorenz et al. acknowledged that their findings in the three sporadic MPNST cell lines that they studied could not be generalized to indicate that all tumors identified as sporadic MPNSTs are not MPNSTs.
To construct a GEM model in which neurofibroma and MPNST pathogenesis were not necessarily dependent upon specific tumor suppressor gene mutations, we generated transgenic mice in which overexpression of the potent Schwann cell mitogen neuregulin-1 (NRG1) was driven by the Schwann cell-specific myelin protein zero (P0) promoter (P0-GGF&#946;3 mice)21. We have previously shown that human neurofibromas, MPNSTs, and MPNST cell lines express several NRG1 isoforms together with the erbB receptor tyrosine kinases (erbB2, erbB3, and erbB4) that mediate NRG1 signaling and that these erbB receptors are constitutively activated22. We have also demonstrated that pharmacologic inhibitors of the erbB kinases potently inhibit MPNST proliferation22, survival23, and migration24. In keeping with our observations in humans, P0-GGF&#946;3 mice develop plexiform neurofibromas25 that progress to become MPNSTs at a high frequency21,25. We have shown that P0-GGF&#946;3 MPNSTs, like their human counterparts, commonly develop mutations of Trp53 and Cdkn2a, as well as numerous other genomic abnormalities that potentially contribute to tumorigenesis25. MPNSTs arising in P0-GGF&#946;3 mice do not have inactivating Nf1 mutations. However, using genetic complementation, we showed that NRG1 promotes tumorigenesis in P0-GGF&#946;3 mice predominantly through the same signaling cascades that are altered by Nf1 loss26; this conclusion is based on our finding that substituting NRG1 overexpression for Nf1 loss in the presence of Trp53 haploinsufficiency (P0-GGF&#946;3;Trp53+/- mice) produces animals in which MPNSTs develop de novo, as is seen in cis-Nf1+/-;Trp53+/- mice27.
To obtain this and other information demonstrating that P0-GGF&#946;3 mice accurately model the processes of neurofibroma pathogenesis and neurofibroma-MPNST progression seen in humans with NF1, we have developed specialized methodologies for processing tissues from these animals, accurately diagnosing their tumors, grading the MPNSTs arising in these mice, establishing and characterizing early-passage P0-GGF&#946;3 and P0-GGF&#946;3;Trp53+/- MPNST cultures and critically comparing the pathology of P0-GGF&#946;3 PNs and MPNSTs and P0-GGF&#946;3;Trp53+/- MPNSTs to that of their human counterparts. Many of these methodologies are generalizable to other GEM models of nervous system neoplasia. Additionally, several of these methodologies are more broadly applicable to GEM models in which neoplasms arise in other organ sites. Consequently, here we present a detailed description of these methodologies.

<table><tbody><tr><td>100 mm Tissue Culture Plates</td><td>Corning Falcon</td><td>353003</td><td></td></tr><tr><td>3, 3&#039;- Diaminobensidine (DAB)</td><td>Vector Laboratories</td><td>SK-400</td><td></td></tr><tr><td>6- well plates</td><td>Corning Costar</td><td>3516</td><td></td></tr><tr><td>Acetic Acid</td><td>Fisher Scientific</td><td>A38-212</td><td></td></tr><tr><td>Alexa Fluor 488 Secondary (Goat Anti-Mouse)</td><td>Invitrogen</td><td>A11029</td><td></td></tr><tr><td>Alexa Fluor 568 Secondary (Goat Anti-Mouse)</td><td>Invitrogen</td><td>A21043 or A11004</td><td></td></tr><tr><td>Alexa Fluor 568 Secondary (Goat Anti-Rabbit)</td><td>Invitrogen</td><td>A11036</td><td></td></tr><tr><td>Ammonium Chloride (NH&lt;sub&gt;4&lt;/sub&gt;Cl)</td><td>Fisher Scientific</td><td>A661-500</td><td></td></tr><tr><td>BCA Protein Assay Kit</td><td>Thermo Scientific</td><td>23225</td><td></td></tr><tr><td>Bovine Serum Albumin</td><td>Fisher Scientific</td><td>BP1600-100</td><td></td></tr><tr><td>Caldesmon</td><td>ABCAM&amp;nbsp;</td><td>E89, ab32330</td><td></td></tr><tr><td>CD117</td><td>Cell Marque</td><td>117R-18-ASR</td><td></td></tr><tr><td>CD163</td><td>Leica</td><td>NCL-L-CD163</td><td></td></tr><tr><td>CD31</td><td>ABCAM&amp;nbsp;</td><td>ab29364</td><td></td></tr><tr><td>CD34</td><td>ABCAM&amp;nbsp;</td><td>ab81289</td><td></td></tr><tr><td>CD86</td><td>ABCAM&amp;nbsp;</td><td>ab53004</td><td></td></tr><tr><td>Cell Scraper</td><td>Sarstedt</td><td>83.183</td><td></td></tr><tr><td>Cell Stripper</td><td>Corning</td><td>25-056-CI</td><td></td></tr><tr><td>Circle Coverslip</td><td>Fisher Scientific</td><td>12-545-100</td><td></td></tr><tr><td>Citrisolve Hybrid (d-limonene-based solvent)</td><td>Decon Laboratories</td><td>5989-27-5</td><td></td></tr><tr><td>Critic Acid</td><td>Fisher Scientific</td><td>A104-500</td><td></td></tr><tr><td>Cytokeratin</td><td>ABCAM&amp;nbsp;</td><td>C-11, ab7753</td><td></td></tr><tr><td>Desmin</td><td>Agilent Dako&amp;nbsp;</td><td>clone D33 (M0760)</td><td></td></tr><tr><td>Diaminobensizdine (DAB) Solution</td><td>Vector Laboratories</td><td>SK-4100</td><td></td></tr><tr><td>DMEM</td><td>Corning</td><td>15-013-CV</td><td></td></tr><tr><td>Eosin Y</td><td>Thermo Scientific</td><td>7111</td><td></td></tr><tr><td>Ethanol (200 Proof)</td><td>Decon Laboratories</td><td>2716</td><td></td></tr><tr><td>Fetal Calf Serum</td><td>Omega Scientific</td><td>FB-01</td><td></td></tr><tr><td>Forksolin</td><td>Sigma-Aldrich</td><td>F6886</td><td></td></tr><tr><td>Glycerol</td><td>Sigma-Aldrich</td><td>G6279</td><td></td></tr><tr><td>Hank&#039;s Balanced Salt Solution (HBSS)</td><td>Corning</td><td>21-022-CV</td><td></td></tr><tr><td>Harris Hematoxylin</td><td>Fisherbrand</td><td>245-677</td><td></td></tr><tr><td>Hemacytometer</td><td>Brightline-Hauser Scientific</td><td>1490</td><td></td></tr><tr><td>Hydrochloric Acid</td><td>Fisher Scientific</td><td>A144-212</td><td></td></tr><tr><td>Hydrogen Peroxide</td><td>Fisher Scientific</td><td>327-500</td><td></td></tr><tr><td>Iba1</td><td>Wako Chemicals</td><td>019-19741</td><td></td></tr><tr><td>ImmPRESS HRP (Peroxidase) Polymer Kit ,Mouse on Mouse</td><td>Vector Laboratories</td><td>MP-2400</td><td></td></tr><tr><td>ImmPRESS HRP (Peroxidase) Polymer Kit, Horse Anti-Rabbit</td><td>Vector Laboratories</td><td>MP-7401</td><td></td></tr><tr><td>Incubator</td><td>Thermo Scientific</td><td>Heracell 240i CO2 incubator</td><td></td></tr><tr><td>Isoflurane</td><td>Piramal</td><td>NDC 66794-017-25</td><td></td></tr><tr><td>Isopropanol</td><td>Fisher Scientific</td><td>A415</td><td></td></tr><tr><td>Ki-67</td><td>Cell Signaling&amp;nbsp;</td><td>12202</td><td></td></tr><tr><td>Laminin</td><td>Thermo Fisher Scientific</td><td>23017015</td><td></td></tr><tr><td>Liquid Nitrogen</td><td></td><td></td><td></td></tr><tr><td>MART1</td><td>ABCAM&amp;nbsp;</td><td>M2-9E3, ab187369</td><td></td></tr><tr><td>Microtome</td><td></td><td></td><td></td></tr><tr><td>Nestin</td><td>Millipore&amp;nbsp;</td><td>Human: MAD5236 (10C2), Human:MAB353 (Rat-401)</td><td></td></tr><tr><td>Neuregulin 1 beta</td><td>In house</td><td>Made by S.L.C. (also available as 396-HB-050/CF from R&amp;amp;D Systems)</td><td></td></tr><tr><td>Neurofibromin</td><td>Santa Cruz Biotechnology&amp;nbsp;</td><td>sc-67</td><td></td></tr><tr><td>NOD.Cg-&lt;em&gt;Prkdc&lt;sup&gt;scid&lt;/sup&gt; Il2rg&lt;sup&gt;tm1Wjl&lt;/sup&gt;&lt;/em&gt;/SzJ mice</td><td>Jackson Laboratory</td><td>5557</td><td></td></tr><tr><td>Nonfat Dry Milk</td><td>Walmart</td><td>Great Value Brand</td><td></td></tr><tr><td>P&lt;sub&gt;0&lt;/sub&gt;-GGF&amp;beta;3 mice</td><td>In house</td><td></td><td></td></tr><tr><td>Paraffin Wax</td><td>Leica</td><td>Paraplast 39601006</td><td></td></tr><tr><td>Parafilm M</td><td>Sigma-Aldrich</td><td>PM-999</td><td></td></tr><tr><td>Paraformaldehyde (4%)</td><td>Thermo Scientific</td><td>J19943-K2</td><td></td></tr><tr><td>Permount (Xylene Mounting Medium)</td><td>Fisher Scientific</td><td>SP15-100</td><td></td></tr><tr><td>pH Meter</td><td>Mettler Toldedo</td><td>Seven Excellence, 8603</td><td></td></tr><tr><td>Phosphate Buffered Saline (Dulbecco&#039;s)</td><td>Corning</td><td>20-031-CV</td><td></td></tr><tr><td>PMEL</td><td>ABCAM&amp;nbsp;</td><td>EP4863(2), ab137078</td><td></td></tr><tr><td>Poly-L-Lysine Hydrobromide</td><td>Sigma-Aldrich</td><td>P5899-5MG</td><td></td></tr><tr><td>Portable Isoflurance Machine</td><td>VetEquip Inhalation Anesthesia Systems</td><td></td><td></td></tr><tr><td>PVA-DABCO (Aqueous Mounting Medium)</td><td>Millipore Sigma</td><td>10981100ML</td><td></td></tr><tr><td>Rice Cooker</td><td>Beech Hamilton</td><td></td><td></td></tr><tr><td>S100B</td><td>Agilent Dako&amp;nbsp;</td><td>Z0311&amp;nbsp; (now GA504)</td><td></td></tr><tr><td>SMA</td><td>Ventana Medical Systems&amp;nbsp;</td><td>clone 1A4</td><td></td></tr><tr><td>Sodium Chloride</td><td>Fisher Scientific</td><td>S640</td><td></td></tr><tr><td>Sodium Citrate (Dihydrate)</td><td>Fisher Scientific</td><td>BP327-1</td><td></td></tr><tr><td>Sox10</td><td>ABCAM&amp;nbsp;</td><td>ab212843</td><td></td></tr><tr><td>Steel histology mold</td><td></td><td></td><td></td></tr><tr><td>Superfrost Plus Microscope Slides</td><td>Fisher Scientific</td><td>12-550-15</td><td></td></tr><tr><td>TCF4/TCFL2&amp;nbsp;</td><td>Cell Signaling&amp;nbsp;</td><td>(CH48H11) #2569</td><td></td></tr><tr><td>Tissue Cassette</td><td></td><td></td><td></td></tr><tr><td>Toluidine Blue</td><td>ACROS Organics</td><td>348600050</td><td></td></tr><tr><td>Triton X-100</td><td>Fisher Scientific</td><td>BP151-500</td><td></td></tr><tr><td>TRIzol</td><td>Invitrogen</td><td>15596026</td><td></td></tr><tr><td>Trypsin</td><td>Corning</td><td>25-051-31</td><td></td></tr></tbody></table>

identifying, diagnosing, and grading malignant peripheral nerve sheath tumors in genetically engineered mouse models

Patients with the autosomal dominant tumor susceptibility syndrome neurofibromatosis type 1 (NF1) commonly develop plexiform neurofibromas (PNs) that subsequently transform into highly aggressive malignant peripheral nerve sheath tumors (MPNSTs). Understanding the process by which a PN transforms into an MPNST would be facilitated by the availability of genetically engineered mouse (GEM) models that accurately replicate the PN-MPNST progression seen in humans with NF1. Unfortunately, GEM models with Nf1 ablation do not fully recapitulate this process. This led us to develop P0-GGF&#946;3 mice, a GEM model in which overexpression of the Schwann cell mitogen neuregulin-1 (NRG1) in Schwann cells results in the development of PNs that progress to become MPNSTs with high frequency. However, to determine whether tumorigenesis and neoplastic progression in P0-GGF&#946;3 mice accurately model the processes seen in NF1 patients, we had to first prove that the pathology of P0-GGF&#946;3 peripheral nerve sheath tumors recapitulates the pathology of their human counterparts.
Here, we describe the specialized methodologies used to accurately diagnose and grade peripheral nervous system neoplasms in GEM models, using P0-GGF&#946;3 and P0-GGF&#946;3;Trp53+/- mice as an example. We describe the histologic, immunohistochemical, and histochemical methods used to diagnose PNs and MPNSTs, how to distinguish these neoplasms from other tumor types that mimic their pathology, and how to grade these neoplasms. We discuss the establishment of early-passage cultures from GEM MPNSTs, how to characterize these cultures using immunocytochemistry, and how to verify their tumorigenicity by establishing allografts. Collectively, these techniques characterize the pathology of PNs and MPNSTs that arise in GEM models and critically compare the pathology of these murine tumors to their human counterparts.

Figure 2 illustrates examples of grossly evident neoplasms arising in P0-GGF&#946;3 mice. Tumors that are easily identifiable with the naked eye may be seen as masses distending body regions as shown in Figure 2A (arrow). When determining whether the neoplasm is potentially a peripheral nerve sheath tumor, it is essential to establish that the tumor is associated with a peripheral nerve. In this instance, an MRI scan (Figure 2B</s...

Author Spotlight: Genetically Engineered Mouse Models and Pathological Characterization of Neurofibromatosis Type 1 Associated Tumors

We have developed a methodology for assessing whether nervous system neoplasms in genetically engineered mice accurately recapitulate the pathology of their human counterparts. Here, we apply these histologic techniques, defined pathologic criteria, and culture methodologies to neurofibromas and malignant peripheral nerve sheath tumors arising in the P0-GGF&#946;3 mouse model.

Identifying, Diagnosing, and Grading Malignant Peripheral Nerve Sheath Tumors in Genetically Engineered Mouse Models

Patients with the autosomal dominant tumor susceptibility syndrome neurofibromatosis type 1 (NF1) commonly develop plexiform neurofibromas (PNs) that ...

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JoVE Journal

Cancer Research

1.5K Views.  Medical University of South Carolina. Onze groep richt zich op neurofibromatose type één en het begrijpen van de pathologie van de kankers die verband houden met de ziekte, plexiforme neurofibromen en kwaadaardige perifere zenuwschedetumoren. Om dit te doen, gebruiken we verschillende technieken, waaronder het gebruik van een genetisch gemanipuleerd muismodel, P0GGF bèta drie, Ons laboratorium en anderen die plexiforme neurofibromen en kwaadaardige perifere zenuwschedetumoren bestuderen, staan voor vergelijkbare uitdagingen. B...

Video: Auteur in de schijnwerpers: genetisch gemanipuleerde muismodellen en pathologische karakterisering van neurofibromatose type 1-geassocieerde tumoren

Induction and Diagnosis of Tumors in Drosophila Imaginal Disc Epithelia

In the early stages of cancer, transformed mutant cells show cytological abnormalities, begin uncontrolled overgrowth, and progressively disrupt tissue organization. Drosophila melanogaster has emerged as a popular experimental model system in cancer biology to study the genetic and cellular mechanisms of tumorigenesis. In particular, genetic tools for Drosophila imaginal discs (developing epithelia in larvae) enable the creation of transformed pro-tumor cells within a normal epithelial tissue, a situation similar to the initial stages of human cancer. A recent study of tumorigenesis in Drosophila wing imaginal discs, however, showed that tumor initiation depends on the tissue-intrinsic cytoarchitecture and the local microenvironment, suggesting that it is important to consider the region-specific susceptibility to tumorigenic stimuli in evaluating tumor phenotypes in imaginal discs. To facilitate phenotypic analysis of tumor progression in imaginal discs, here we describe a protocol for genetic experiments using the GAL4-UAS system to induce neoplastic tumors in wing imaginal discs. We further introduce a diagnosis method to classify the phenotypes of clonal lesions induced in imaginal epithelia, as a clear classification method to discriminate various stages of tumor progression (such as hyperplasia, dysplasia, or neoplasia) had not been described before. These methods might be broadly applicable to the clonal analysis of tumor phenotypes in various organs in Drosophila.

Induction and Diagnosis of Tumors in Drosophila Imaginal Disc Epithelia

Mosaic clone analysis in Drosophila imaginal disc epithelia is a powerful model system to study the genetic and cellular mechanisms of tumorigenesis. Here we describe a protocol to induce tumors in Drosophila wing imaginal discs using the GAL4-UAS system, and introduce a diagnosis method to classify the tumor phenotypes.

In the early stages of cancer, transformed mutant cells show cytological abnormalities, begin uncontrolled overgrowth, and progressively disrupt tissue ...

A Genetically Engineered Mouse Model of Sporadic Colorectal Cancer

Despite the advantages of easy applicability and cost-effectiveness, colorectal cancer mouse models based on tumor cell injection have severe limitations and do not accurately simulate tumor biology and tumor cell dissemination. Genetically engineered mouse models have been introduced to overcome these limitations; however, such models are technically demanding, especially in large organs such as the colon in which only a single tumor is desired.
As a result, an immunocompetent, genetically engineered mouse model of colorectal cancer was developed which develops highly uniform tumors and can be used for tumor biology studies as well as therapeutic trials. Tumor development is initiated by surgical, segmental infection of the distal colon with adeno-cre virus in compound conditionally mutant mice. The tumors can be easily detected and monitored via colonoscopy. We here describe the surgical technique of segmental adeno-cre infection of the colon, the surveillance of the tumor via high-resolution colonoscopy and present the resulting colorectal tumors.

A protocol for the establishment of a genetically engineered mouse model of colorectal cancer by segmental adeno-cre infection and its surveillance via high-resolution colonoscopy is presented.

Despite the advantages of easy applicability and cost-effectiveness, colorectal cancer mouse models based on tumor cell injection have severe limitations ...

Development of a Human Preclinical Model of Osteoclastogenesis from Peripheral Blood Monocytes Co-cultured with Breast Cancer Cell Lines

The crosstalk between tumor cells and bone cells in the bone microenvironment is crucial to understanding the mechanism of bone metastasis formation. We developed an in vitro fully human preclinical model of a co-culture of breast cancer cells and monocytes undergoing differentiation towards osteoclasts. We optimized a model of osteoclastogenesis starting from a sample of peripheral blood collected from healthy donors. Peripheral blood mononuclear cells (PBMCs) were first separated by density gradient centrifugation, seeded at a high density and induced to differentiate by adding two growth factors (GFs): receptor activator of nuclear factor-&#954;B ligand (RANKL) and macrophage colony-stimulating factor (MCSF). The cells were left in culture for 14 days and then fixed and analyzed by downstream analysis. In osteolytic bone metastases, one of the effects of cancer cell arrival in bone is the induction of osteoclastogenesis. We thus challenged our model with co-cultures of breast cancer cells to study the differentiation power of cancer cells with respect to GFs. A straightforward way of studying cancer cell-osteoclast interaction is to perform indirect co-cultures based on the use of conditioned medium collected from breast cancer cell cultures and mixed with fresh medium. This mixture is then used to induce osteoclast differentiation. We also optimized a method of direct co-culture in which cancer cells and monocytes undergoing differentiation share the medium and exchange secreted factors. This is a significant improvement over the original indirect co-culture method as researchers can observe the reciprocal interactions of the two cell types and perform downstream analyses for both cancer cells and osteoclasts. This method enables us to study the effect of drugs on the metastatic bone microenvironment and to seed cell lines other than those derived from breast cancer. The model can also be used to study other diseases such as osteoporosis or other bone conditions.

This protocol describes development of an in vitro human preclinical model of osteoclastogenesis from peripheral blood monocytes cultured with breast cancer cell lines to mimic the cancer cell-osteoclast interaction. The model could be used to further our understanding of bone metastasis formation and improve therapeutic options.

The crosstalk between tumor cells and bone cells in the bone microenvironment is crucial to understanding the mechanism of bone metastasis formation. We ...

Utilizing High Resolution Ultrasound to Monitor Tumor Onset and Growth in Genetically Engineered Pancreatic Cancer Models

The LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre (KPC) mouse model represents an established and frequently used transgenic model to evaluate novel therapies in pancreatic cancer. Tumor onset is variable in the KPC model between 8 weeks and several months. Therefore, non-invasive imaging tools are required to screen for tumor onset and monitor for response to treatment. To address this issue, different approaches have emerged over the last years. High resolution ultrasound has major advantages such as non-invasiveness, fast session times and a high image resolution without radiation exposure. However, ultrasound in mice is not trivial and sufficient anatomical knowledge and practical skills are required to successfully perform high resolution ultrasound in preclinical pancreatic cancer models. With the following article, a detailed hands-on guide for abdominal ultrasound in murine models with a particular focus on endogenous pancreatic cancer models is presented. Furthermore, a summary of common mistakes and how to avoid them is provided.

This article describes the utilization of high-resolution ultrasound in genetically engineered pancreatic cancer mice. The primary aim is to provide a detailed instruction for detection and evaluation of endogenous pancreatic tumors.

The LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre (KPC) mouse model represents an established and frequently used transgenic model to evaluate novel ...

Enrichment and Characterization of the Tumor Immune and Non-immune Microenvironments in Established Subcutaneous Murine Tumors

The tumor immune microenvironment (TIME) has recently been recognized as a critical mediator of treatment response in solid tumors, especially for immunotherapies. Recent clinical advances in immunotherapy highlight the need for reproducible methods to accurately and thoroughly characterize the tumor and its associated immune infiltrate. Tumor enzymatic digestion and flow cytometric analysis allow broad characterization of numerous immune cell subsets and phenotypes; however, depth of analysis is often limited by fluorophore restrictions on panel design and the need to acquire large tumor samples to observe rare immune populations of interest. Thus, we have developed an effective and high throughput method for separating and enriching the tumor immune infiltrate from the non-immune tumor components. The described tumor digestion and centrifugal density-based separation technique allows separate characterization of tumor and tumor immune infiltrate fractions and preserves cellular viability, and thus, provides a broad characterization of the tumor immunologic state. This method was used to characterize the extensive spatial immune heterogeneity in solid tumors, which further demonstrates the need for consistent whole tumor immunologic profiling techniques. Overall, this method provides an effective and adaptable technique for the immunologic characterization of subcutaneous solid murine tumors; as such, this tool can be used to better characterize the tumoral immunologic features and in the preclinical evaluation of novel immunotherapeutic strategies.

Here we describe a method to separate and enrich components of the tumor immune and non-immune microenvironment in established subcutaneous tumors. This technique allows for the separate analysis of tumor immune infiltrate and non-immune tumor fractions which can permit comprehensive characterization of the tumor immune microenvironment.

The tumor immune microenvironment (TIME) has recently been recognized as a critical mediator of treatment response in solid tumors, especially for ...

Establishment of Gastric Cancer Patient-derived Xenograft Models and Primary Cell Lines

The use of preclinical models to advance our understanding of tumor biology and investigate the efficacy of therapeutic agents is key to cancer research. Although there are many established gastric cancer cell lines and many conventional transgenic mouse models for preclinical research, the disadvantages of these in vitro and in vivo models limit their applications. Because the characteristics of these models have changed in culture, they no longer model tumor heterogeneity, and their responses have not been able to predict responses in humans. Thus, alternative models that better represent tumor heterogeneity are being developed. Patient-derived xenograft (PDX) models preserve the histologic appearance of cancer cells, retain intratumoral heterogeneity, and better reflect the relevant human components of the tumor microenvironment. However, it usually takes 4-8 months to develop a PDX model, which is longer than the expected survival of many gastric patients. For this reason, establishing primary cancer cell lines may be an effective complementary method for drug response studies. The current protocol describes methods to establish PDX models and primary cancer cell lines from surgical gastric cancer samples. These methods provide a useful tool for drug development and cancer biology research.

The current protocol describes methods to establish patient-derived xenograft (PDX) models and primary cancer cell lines from surgical gastric cancer samples. The methods provide a useful tool for drug development and cancer biology research.

The use of preclinical models to advance our understanding of tumor biology and investigate the efficacy of therapeutic agents is key to cancer research. ...

In Vitro Establishment of a Genetically Engineered Murine Head and Neck Cancer Cell Line using an Adeno-Associated Virus-Cas9 System

The use of primary normal epithelial cells makes it possible to reproducibly induce genomic alterations required for cellular transformation by introducing specific mutations in oncogenes and tumor suppressor genes, using clustered regulatory interspaced short palindromic repeat (CRISPR)-based genome editing technology in mice. This technology allows us to accurately mimic the genetic changes that occur in human cancers using mice. By genetically transforming murine primary cells, we can better study cancer development, progression, treatment, and diagnosis. In this study, we used Cre-inducible Cas9 mouse tongue epithelial cells to enable genome editing using adeno-associated virus (AAV) in vitro. Specifically, by altering KRAS, p53, and APC in normal tongue epithelial cells, we generated a murine head and neck cancer (HNC) cell line in vitro,which is tumorigenic in syngeneic mice. The method presented here describes in detail how to generate HNC cell lines with specific genomic alterations and explains their suitability for predicting tumor progression in syngeneic mice. We envision that this promising method will be informative and useful to study tumor biology and therapy of HNC.

Development of murine models with specific genes mutated in head and neck cancer patients is required for understanding of neoplasia. Here, we present a protocol for in vitro transformation of primary murine tongue cells using an adeno-associated virus-Cas9 system to generate murine HNC cell lines with specific genomic alterations.

The use of primary normal epithelial cells makes it possible to reproducibly induce genomic alterations required for cellular transformation by ...

Orthotopic Transplantation of Breast Tumors as Preclinical Models for Breast Cancer

Preclinical models that faithfully recapitulate tumor heterogeneity and therapeutic response are critical for translational breast cancer research. Immortalized cell lines are easy to grow and genetically modify to study molecular mechanisms, yet the selective pressure from cell culture often leads to genetic and epigenetic alterations over time. Patient-derived xenograft (PDX) models faithfully recapitulate the heterogeneity and drug response of human breast tumors. PDX models exhibit a relatively short latency after orthotopic transplantation that facilitates the investigation of breast tumor biology and drug response. The transplantable genetically engineered mouse models allow the study of breast tumor immunity. The current protocol describes the method to orthotopically transplant breast tumor fragments into the mammary fat pad followed by drug treatments. These preclinical models provide valuable approaches to investigate breast tumor biology, drug response, biomarker discovery and mechanisms of drug resistance.

Patient-derived xenograft (PDX) models and transplantable genetically engineered mouse models faithfully recapitulate human disease and are preferred models for basic and translational breast cancer research. Here, a method is described to orthotopically transplant breast tumor fragments into the mammary fat pad to study tumor biology and evaluate drug response.

Preclinical models that faithfully recapitulate tumor heterogeneity and therapeutic response are critical for translational breast cancer research. ...

Defining Gene Functions in Tumorigenesis by Ex vivo Ablation of Floxed Alleles in Malignant Peripheral Nerve Sheath Tumor Cells

The development of new drugs that precisely target key proteins in human cancers is fundamentally altering cancer therapeutics. However, before these drugs can be used, their target proteins must be validated as therapeutic targets in specific cancer types. This validation is often performed by knocking out the gene encoding the candidate therapeutic target in a genetically engineered mouse (GEM) model of cancer and determining what effect this has on tumor growth. Unfortunately, technical issues such as embryonic lethality in conventional knockouts and mosaicism in conditional knockouts often limit this approach. To overcome these limitations, an approach to ablating a floxed embryonic lethal gene of interest in short-term cultures of malignant peripheral nerve sheath tumors (MPNSTs) generated in a GEM model was developed.
This paper describes how to establish a mouse model with the appropriate genotype, derive short-term tumor cultures from these animals, and then ablate the floxed embryonic lethal gene using an adenoviral vector that expresses Cre recombinase and enhanced green fluorescent protein (eGFP). Purification of cells transduced with adenovirus using fluorescence-activated cell sorting (FACS) and the quantification of the effects that gene ablation exerts on cellular proliferation, viability, the transcriptome, and orthotopic allograft growth is then detailed. These methodologies provide an effective and generalizable approach to identifying and validating therapeutic targets in vitro and in vivo. These approaches also provide a renewable source of low-passage tumor-derived cells with reduced in vitro growth artifacts. This allows the biological role of the targeted gene to be studied in diverse biologic processes such as migration, invasion, metastasis, and intercellular communication mediated by the secretome.

Defining Gene Functions in Tumorigenesis by Ex vivo Ablation of Floxed Alleles in Malignant Peripheral Nerve Sheath Tumor Cells

Here, we present a protocol for performing gene knockouts that are embryonic lethal in vivo in genetically engineered mouse model-derived tumors and then assessing the effect that the knockout has on tumor growth, proliferation, survival, migration, invasion, and the transcriptome in vitro and in vivo.

The development of new drugs that precisely target key proteins in human cancers is fundamentally altering cancer therapeutics. However, before these ...

Genome-Scale Screening to Identify and Compare Therapeutic Targets in Tumors

Genetic Profiling and Genome-Scale Dropout Screening to Identify Therapeutic Targets in Mouse Models of Malignant Peripheral Nerve Sheath Tumor

Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are derived from Schwann cells or their precursors. In patients with the tumor susceptibility syndrome neurofibromatosis type 1 (NF1), MPNSTs are the most common malignancy and the leading cause of death. These rare and aggressive soft-tissue sarcomas offer a stark future, with 5-year disease-free survival rates of 34-60%. Treatment options for individuals with MPNSTs are disappointingly limited, with disfiguring surgery being the foremost treatment option. Many once-promising therapies such as tipifarnib, an inhibitor of Ras signaling, have failed clinically. Likewise, phase II clinical trials with erlotinib, which targets the epidermal growth factor (EFGR), and sorafenib, which targets the vascular endothelial growth factor receptor (VEGF), platelet-derived growth factor receptor (PDGF), and Raf, in combination with standard chemotherapy, have also failed to produce a response in patients. 
In recent years, functional genomic screening methods combined with genetic profiling of cancer cell lines have proven useful for identifying essential cytoplasmic signaling pathways and the development of target-specific therapies. In the case of rare tumor types, a variation of this approach known as cross-species comparative oncogenomics is increasingly being used to identify novel therapeutic targets. In cross-species comparative oncogenomics, genetic profiling and functional genomics are performed in genetically engineered mouse (GEM) models and the results are then validated in the rare human specimens and cell lines that are available. 
This paper describes how to identify candidate driver gene mutations in human and mouse MPNST cells using whole exome sequencing (WES). We then describe how to perform genome-scale shRNA screens to identify and compare critical signaling pathways in mouse and human MPNST cells and identify druggable targets in these pathways. These methodologies provide an effective approach to identifying new therapeutic targets in a variety of human cancer types.

Author Spotlight: Finding New Therapeutic Targets for Malignant Peripheral Nerve Sheath Tumor Through Genome-Scale shRNA Screens 

We have developed a cross-species comparative oncogenomics approach utilizing genomic analyses and functional genomic screens to identify and compare therapeutic targets in tumors arising in genetically engineered mouse models and the corresponding human tumor type.

Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are derived from Schwann cells or their precursors. In patients with the tumor susceptibility syndrome ...

Identifying, Diagnosing, and Grading Malignant Peripheral Nerve Sheath Tumors in Genetically Engineered Mouse Models

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