bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract B12: Molecular mechanisms of HIF-1a and HIF-2a activation in nonmalignant cells at the premetastatic niche: Effects on metastatic success
Authors: Branco-Price Cristina , Palazon Asis , Xie Jessica , Johnson Randall S. 
Published: May 2015

Abstract
Tumor hypoxia and the hypoxia-inducible transcription factors (HIF) have been thoroughly characterized in solid tumors, and they are active participants in pathways promoting tumor growth and dispersion.
However, despite their well-known pro-tumorigenic role when stabilized in cancer cells, HIF activation in other cell types has been shown to be less consistent and often antagonistic. We have previously shown that specific deletion of HIF-1a in endothelial cells results in reduced tumor cell migration and metastatic incidence, whereas deletion of HIF-2a in this same cell type has the opposite effect. This phenomenon also involved endothelial-specific nitric oxide production via the inducible NOS (iNOS).
Endothelial cells are at the interface between the primary tumor and the rest of the body, and play a role not only in tumor maintenance and growth, but also in metastatic success and proliferation at secondary sites.
Immune/inflammatory cells are also known to be active players in tumor cell motility and establishment. We are interested in understanding the role of non-malignant cell types in the metastatic process, specifically
(i) signals that trigger HIF-1a or HIF-2a activation at metastatic sites and (ii) how does the stabilization of either HIF isoform (or both) affect tumor cell recruitment and establishment.
This work uses primary cells isolated from different genotypic backgrounds to dissect the hypoxia-response regulatory pathways, using a combination of screenings: transcription factor activation and downstream transcriptional targets, in order to build a map of HIF-dependent metabolism. Specifically, we are interested in the pathways which activation or silencing could have an effect on vascular morphology, permeability, inter-cellular signaling and post-extravasation events. Complementary studies in physiological models of extravasation were used for histological, molecular and biochemical analysis of hypoxic tissue to study molecular players identified by our initial ex-vivo screening.
Citation Format: Cristina Branco-Price, Asis Palazon, Jessica Xie, Randall S. Johnson. Molecular mechanisms of HIF-1a and HIF-2a activation in nonmalignant cells at the premetastatic niche: Effects on metastatic success. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B12. doi:10.1158/1538-7445.CHTME14-B12
Abstract B28: Autotaxin, LPA1 and LPA5 receptors in the tumor microenvironment determine melanoma invasion and metastasis
Authors: Lee Sue-Chin , Fujiwara Yuko , Liu Jianxiong , Yue Junming , Tsukahara Ryoko , Szabo Erzsebet , Patil Renukadevi , Miller Duane D. , Balazs Louisa , Oravecz Tamas , Tigyi Gabor J. 
Published: May 2015

Abstract
Autotaxin (ATX), a lysophospholipase D that generates the growth factor-like mediator lysophosphatidic acid LPA, is up-regulated in metastatic and chemotherapy-resistant carcinomas. Many cancer cells secrete ATX, and it contributes to their invasive properties. The biological functions of ATX are mediated by LPA acting on G protein-coupled receptors (LPAR1-8). Many cancers overexpress multiple subtypes of LPAR and the overexpression of LPAR leads to malignant transformation, metastasis, and resistance to therapy. We have previously shown that knockdown of ATX expression in B16F10 melanoma cells decreased tumor invasion in vitro and lung metastasis in vivo. In our present study, we sought to understand the roles of LPAR both in the tumor cells and stromal cells of the tumor microenvironment.
B16F10 melanoma cells predominantly express the LPA5 receptor. We found that these cells do not invade across a matrigel layer in response to LPA. shRNA knockdown of LPA5 receptors in B16F10 attenuates this inhibition, suggesting that the LPA5 receptor acts as an anti-invasive receptor in these tumor cells. Interestingly, we identified a different role for host LPA5 receptor. We found that the incidence of B16F10 lung metastasis was significantly reduced in the LPA5 knockout mice compared to wild type mice. In addition, LPA1 knockout mice also showed diminished B16F10 lung metastasis suggesting that host LPA1 and LPA5 receptors play critical roles in the seeding of metastasis. The decrease in tumor cell residence in the lungs of these knockout animals was apparent at 24 hours after injection. However, deletion of LPA1 or LPA5 did not affect the subcutaneous growth of B16F10 tumors.
In summary, our results suggest that LPAR, in particular LPA5 and LPA1 receptors in tumor and stromal cells may play different roles in invasion and the seeding of metastasis.
Citation Format: Sue-Chin Lee, Yuko Fujiwara, Jianxiong Liu, Junming Yue, Ryoko Tsukahara, Erzsebet Szabo, Renukadevi Patil, Duane D. Miller, Louisa Balazs, Tamas Oravecz, Gabor J. Tigyi. Autotaxin, LPA1 and LPA5 receptors in the tumor microenvironment determine melanoma invasion and metastasis. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B28. doi:10.1158/1538-7445.CHTME14-B28
Abstract B33: Langerhans cells prevent melanocytic nevus development and transformation in mice.
Authors: Nasti Tahseen H. , Tsuruta Yuko , McKay Kris , Athar Mohammad , Elmets Craig , Timares Laura 
Published: May 2015

Abstract
The function of Langerhans cells (LCs) in the skin immune system is unclear, and a matter of intense debate. In different mouse models LCs have been shown to induce antitumor immunity or promote skin squamous cell carcinoma (SCC). Their role in the control or promotion of melanoma is not known. We assessed LC's role in the development of DMBA-TPA induced pigmented benign and transformed lesions in a novel mouse model. Transgenic HuLang-DTA+/- C57Bl/6 mice, which selectively ablate epidermal LCs, were crossed with C3H/HeN mice to generate F1 LC knockout (KO) and WT littermate controls. LC-KO mice developed 40% more and 2-fold larger melanocytic lesions than WT. Cell suspensions from LC-KO pigmented skin lesions contained increased CD4+ Foxp3+ regulatory T cells and CD11b-/loGr-1hi cells, consistent with an immunosuppressive microenvironment. CD11c+CD11b+Ly6C+ APCs or MHCII+ cell numbers were fewer in lesions from LC-KO as compared to WT mice. Nests of melanocytic cells were observed at a higher frequency in draining lymph nodes (dLNs) from LC-KO as compared to WT; DLN cells contained increased numbers of TRP2+ cells and routinely gave rise to proliferative melanocytic cell lines. Real-time PCR analysis of epidermal cDNA from TPA treated LC-KO, as compared to WT, demonstrated a profound loss of IL-10, IL-12p35 and IL-12p40, indicating LCs as the major source. Further, IL-23 steady state levels in the epidermis of LC-KO are increased greater than 3-fold over WT, indicating that LCs normally suppress keratinocyte production of IL-23. Thus, in contrast to SCC, LCs inhibit development of benign and metastatic pigmented tumors. This novel murine model will be useful in elucidating transformation mechanisms and identifying novel therapeutic targets that may prevent metastatic melanoma.
Citation Format: Tahseen H. Nasti, Yuko Tsuruta, Kris McKay, Mohammad Athar, Craig Elmets, Laura Timares. Langerhans cells prevent melanocytic nevus development and transformation in mice.. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B33. doi:10.1158/1538-7445.CHTME14-B33
Abstract B43: Intratumoral heterogeneity of ovarian cancer stem cells and their interactions with the tumor microenvironment
Authors: Tzukerman Maty , Abelson Sagi , Shamai Yeela , Berger Liron , Skorecki Karl 
Published: May 2015

Abstract
Intratumoral heterogeneity challenges existing paradigms for anti-cancer therapy. We have previously demonstrated that the human embryonic stem cells (hESC)-derived cellular microenvironment in immunocompromised mice, enables functional distinction of heterogeneous tumor cells, including cells which do not grow into a tumor in conventional direct tumor xenograft platform. We have identified and characterized six cancer cell subpopulations each clonally expanded from a single cell, derived from human ovarian clear cell carcinoma of a single tumor, to demonstrate striking intratumoral phenotypic heterogeneity that is dynamically dependent on the tumor growth microenvironment. These cancer cell subpopulations, characterized as cancer stem cell subpopulations, faithfully recapitulate the full spectrum of histological phenotypic heterogeneity known for human ovarian clear cell carcinoma. Each of the six subpopulations displays a different level of morphologic and tumorigenic differentiation wherein growth in the hESC-derived microenvironment favors growth of CD44+/aldehyde dehydrogenase positive pockets of self-renewing cells that sustain tumor growth through a process of tumorigenic differentiation into CD44-/aldehyde dehydrogenase negative derivatives. Strikingly, these derivative cells display microenvironment-dependent plasticity with the capacity to restore self-renewal markers and CD44 expression. We delineated the distinct gene expression and epigenetic profiles of two such subpopulations, representing extremes of phenotypic heterogeneity in terms of niche-dependent self-renewal and tumorigenic differentiation. By combining Gene Set Enrichment, Gene Ontology and Pathway-focused array analyses with methylation status and secretome analyses, we propose a suite of robust differences in tumor self-renewal and differentiation pathways, and interaction with stromal cells in the tumor microenvironment that underlay the striking intratumoral phenotypic heterogeneity which characterized this and other solid tumor malignancies.
Citation Format: Maty Tzukerman, Sagi Abelson, Yeela Shamai, Liron Berger, Karl Skorecki. Intratumoral heterogeneity of ovarian cancer stem cells and their interactions with the tumor microenvironment. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B43. doi:10.1158/1538-7445.CHTME14-B43
Abstract B44: The microRNA-200/Zeb1 axis regulates ECM-dependent Src signaling, cytoskeletal changes and cancer cell invasion
Authors: Ungewiss Christin , Roybal Jonathon D. , Peng David H. , Gibbons Don L. 
Published: May 2015

Abstract
The microRNA-200 family (miR-200) has been shown to be a master regulator of epithelial-to-mesenchymal transition (EMT), partially through a double-negative feedback loop with the transcription repressor Zeb1, allowing cells to acquire an invasive and metastatic phenotype. Using our mutant Kras and p53 murine model of metastatic lung adenocarcinoma, we are investigating the role of the Zeb1/miR-200 axis in regulating cytoskeletal reorganization, a characteristic requirement of cell motility and invasion. Functional assays demonstrated differential actin reorganization within cell lines with different miR-200 levels based upon the extracellular matrix composition, leading us to hypothesize that miR-200 regulates the activation of signaling pathways that mediate a pro-invasive cytoskeletal reorganization. Based upon the importance of cell-matrix interactions in producing cellular activation we identified the Src pathway as a critical mediator of invasion upon miR-200 repression in murine and human lung cancer cell lines. Pharmacologic inhibition of Src significantly reduces in vitro cell migration and invasion in Boyden chamber assays and in 3D cell cultures, which can be mimicked using Integrin β1 blockade. Biochemical analysis of this Src inhibition reveals a significant reduction in the phosphorylated FAK and cortactin levels, two downstream targets of Src. TGFβ stimulation is a strong EMT inducer, producing miR-200 repression and Src activation in our models, which can be blocked biochemically using Src inhibitors, with associated phenotypic changes in 2D and 3D cultures. This data suggests that miR-200 regulates the cell-matrix contact (e.g. integrins), acting through the Src pathway and modulating central players in actin dynamics to promote actin reorganization and invasion.
Citation Format: Christin Ungewiss, Jonathon D. Roybal, David H. Peng, Don L. Gibbons. The microRNA-200/Zeb1 axis regulates ECM-dependent Src signaling, cytoskeletal changes and cancer cell invasion. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B44. doi:10.1158/1538-7445.CHTME14-B44
Abstract B57: Quantifying the contribution of matrix metalloproteinases to the development of the pre-metastatic niche in the lung and liver microenvironments
Authors: Hallett Miranda A. , Dozier E. Ashley , Roland Joseph T. , Fingleton Barbara 
Published: May 2015

Abstract
The leading cause of cancer mortality is metastasis of a primary tumor to distant organs. It is thought that stromal micro-environmental changes occur at these secondary sites before the arrival of tumor cells, which facilitate future colonization and outgrowth. This occurrence is commonly termed as the formation of the “pre-metastatic niche.” Specific factors altered at pre-metastatic niches have already been described in literature (Nature. 2005 Dec 8;438(7069):820-7). These include VEGFR-1, VLA-4 and Fibronectin. Matrix Metalloproteinases (MMPs), known for their involvement in tumor invasion and metastasis, have also been implicated in niche formation. Our goals are to (1) determine the roles of MMPs in generation of the pre-metastatic niche and (2) develop a method of quantification for these niches in the lung utilizing a malignant breast cancer type.
In a distant murine LLC-implantation model, we developed immunofluorescent (IF) staining techniques to define pre-metastatic niches within the lung based on the molecules identified by Kaplan et al. Within this same model, qRT-PCR indicated a substantial increase in lung MMP9 (Gelatinase B) gene expression. This led us to reproduce the pre-metastatic niche within a breast cancer model using a time-coursed malignant murine 4T1-GFP implantation model within Balb/c mammary glands. Visualization was again achieved by IF staining of known factors obtained from Kaplan et al. We utilized these models and the clusters formed to create an algorithm for quantifying the pre-metastatic niche. To confirm this algorithm is specific for premetastatic niches in metastatic tumor models, we also implanted 4T1-GFP cells into MMP9-/- Balb/c mice. These mice result in unorganized protein expression and lack of cluster formation. In addition we utilized a non-metastatic mammary tumor model, 67NR also implanted in Balb/c mice to serve as a negative control for our algorithm. Thus, to confirm the pre-metastatic niche is specific to metastatic tumor models.
Eventually, pre-metastatic MMP activity may indicate potential roles and markers for metastatic spread. Further, this algorithm will provide a new quantitative standard for the field. Thus, this algorithm has translational potential as a test for specific drug efficacy.
Citation Format: Miranda A. Hallett, E. Ashley Dozier, Joseph T. Roland, Barbara Fingleton. Quantifying the contribution of matrix metalloproteinases to the development of the pre-metastatic niche in the lung and liver microenvironments. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B57. doi:10.1158/1538-7445.CHTME14-B57
Abstract B65: Proteolytic shedding of the cell adhesion molecule ALCAM generates a spatial and context-dependent heterogeneity important for metastasis.
Authors: Hansen Amanda G. , Hebron Katie , Palmer Trenis D. , Arnold Shanna , Zijlstra Andries 
Published: May 2015

Abstract
Heterogeneity in the tumor microenvironment is dictated in part by context-dependent changes in cell-cell interactions. Subpopulations of tumor cells can responding to local micro-environmental changes in a manner that distinguishes them biochemically as well as behaviorally from the rest of the tumor. We identified such a phenomenon in the proteolytic shedding of the cell adhesion molecule ALCAM (Activated Leukocyte Cell Adhesion Molecule). ALCAM controls cell adhesion in a variety of cell types including T-cells, epithelial cells, neurons and endothelial cell. Although ALCAM mRNA is detected in all epithelial tissues and the tumors they give rise to, the detection of cell-surface ALCAM is highly variable, being strong in some regions of the tumor while completely absent in adjacent tumor cells. Through molecular analysis of cell-surface ALCAM we determined that this adhesion molecule is shed from the surface by ADAM17 in response to cytokines from the local milieu.
Although ALCAM shedding is common in cancer, the loss of ALCAM greatly diminishes metastasis, thereby suggesting that ALCAM remains necessary for tumor progression. Indeed, ALCAM shedding supports a dynamic regulation of cell adhesion which, in turn, supports tumor cell dissemination. Considering that the proteolytic processing of ALCAM is functionally important in tumor progression, the detection of ALCAM shedding should be a molecular indicator of disease progression. Indeed, through analysis of retrospective patient cohorts, we demonstrated ALCAM shedding to be a prognostic indicator of disease progression in cancers of the colon, kidney and bladder.
Our observations demonstrate that spatial and context-dependent heterogeneity can be accomplished through post-translational proteolysis of cell adhesion molecules. This process enables tumor cells to respond dynamically to the local milieu and disseminate to a more hospitable environment. Identifying this proteolysis in cancer patients through the detection of ALCAM shedding can predict metastatic progression and long-term patient outcome.
Citation Format: Amanda G. Hansen, Katie Hebron, Trenis D. Palmer, Shanna Arnold, Andries Zijlstra. Proteolytic shedding of the cell adhesion molecule ALCAM generates a spatial and context-dependent heterogeneity important for metastasis.. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B65. doi:10.1158/1538-7445.CHTME14-B65
Abstract B72: Serine/threonine kinase MLK4 is a master regulator for proneural-mesenchymal transformation of glioma stem cells
Authors: Sunghak Kim , Violaine Rosenstiel-Goidts , Cheng Shi-Yuan , Ichiro Nakano 
Published: May 2015

Abstract
High-grade glioma is a highly aggressive form of brain cancer associated with a poor prognosis. Recently, we identified that mesenchymal glioma stem cells (Mes GSCs) of HGG are linked to radiation resistance and proneural (PN) GSCs acquire Mes identity via radiation treatment. Here we performed a combined kinome-wide RNA interference screen with genome wide expression analysis to identify kinase-encoding genes that are essential for mesenchymal identity of GSCs. Through this stepwise screening with patient-derived GSC samples, we identified the serine/threonine kinase MLK4 as a key regulator for Mes GSC survival and cell cycle progression in vitro and tumor initiation and propagation in vivo. In addition, overexpression of MLK4 promotes, while both its gene-specific shRNA and pharmacological inhibition attenuate, proneural-mesenchymal transformation (PMT) of GSCs. In patient-derived GSCs, expression of MLK4 protein positively correlated with endogenous EGFRvIII expression and the in vivo growth of mouse xenografts derived from glioma cells with EGFRvIII expression was prominently inhibited by MLK4 knockdown. MLK4-overexpressing PN GSCs acquired radiation resistance, while MLK4 elimination by shRNA radiosensitized Mes GSCs. Patients with a higher MLK4 expression showed reduced survival in CD44-high populations. Collectively, these data indicate that MLK4 as a plausible target for therapy against Mes GBM as well as post-irradiation PN GBM.
Citation Format: Kim Sunghak, Rosenstiel-Goidts Violaine, Shi-Yuan Cheng, Nakano Ichiro. Serine/threonine kinase MLK4 is a master regulator for proneural-mesenchymal transformation of glioma stem cells. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B72. doi:10.1158/1538-7445.CHTME14-B72
Abstract B76: Novel human 3D in vitro invasion model identifies tumor and stroma heterogeneity in squamous cell carcinoma
Authors: Berning Manuel , Boukamp Petra 
Published: May 2015

Abstract
3D in vitro skin models are valuable research tools to investigate normal keratinocyte as well as skin carcinoma cell interaction with dermal fibroblasts. Currently, the models lack either a structured vital human extracellular matrix or long-term stability and longevity. Therefore, we aimed at a new 3D in vitro skin model for normal human epidermis and tumorigenic stages of skin cancer.
This model is based on dermal equivalents containing a highly structured cell-derived matrix (CDM) produced by human dermal fibroblasts. First, we show that the CDM dermal equivalent supports a high structural integrity of the skin model and maintains a vital epidermis for six months. The epidermis is well-stratifying and differentiates in a regular orthokeratotic pattern. Transmission electron microscopy reveals ultrastructural entities as basement membranes, hemidesmosomes, desmosomes, keratohyalin granulae and lamellar bodies. In line, the molecular differentiation markers are properly distributed. Second, five non-tumorigenic and tumorigenic HaCaT keratinocyte variants are tested for their proliferation, differentiation and invasion capacities. After four weeks of co-cultivation the tumorigenic HaCaT variants show hyperproliferative epithelia and lose the capability of an ordered stratification and differentiation. Furthermore, they destroy the basement membrane as well as the extracellular matrix and invade the dermal equivalent. Moreover, seven squamous cell carcinoma (SCC) cell lines were co-cultivated with the CDM dermal equivalent. All SCC cells form hyperproliferative epithelia that heavily invade the extracellular matrix. Remarkably, the epithelia are individually distinct for their invasion and differentiation capacity. Thus, the CDM-based skin cancer model is suitable for demonstrating the heterogeneity of SCC tumors and their interaction with the microenvironment.
In conclusion, the CDM model for normal skin and tumorigenic keratinocytes provides a novel tool to investigate keratinocyte-fibroblast interactions and microenvironment modulations during SCC development. Therefore, this system will provide further insights into mechanistic processes and the interaction of SCCs with their tumor microenvironment.
Citation Format: Manuel Berning, Petra Boukamp. Novel human 3D in vitro invasion model identifies tumor and stroma heterogeneity in squamous cell carcinoma. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B76. doi:10.1158/1538-7445.CHTME14-B76