bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract C24: Beyond EMT: Vimentin function in lung cancer metastasis
Authors: Salgueiro Alessandra M. , Gilbert-Ross Melissa , Havel Lauren S. , Shupe John , Koyen Allyson E. , Grossniklaus Hans E. , Sica Gabriel , Marcus Adam I. 
Published: October 2016

Abstract
Vimentin is an intermediate filament protein that has been used in the clinic as a biomarker for metastatic potential and poor patient prognosis across numerous solid tumor types; however, little is known about how vimentin might contribute to cancer progression and metastasis. Here we created a novel genetically engineered mouse model (GEMM) to study the role of vimentin in lung cancer progression and metastasis. We first re-developed an LSL-KrasG12D,LKB1fl/fl mouse model whereby intranasal administration of lentiviral Cre recombinase causes a KrasG12D mutation and LKB1 knockout in the lungs. In this model Kras/Lkb1 GEMM (termed KLV+/+), approximately half the mice that develop primary lung tumors in 8-10 weeks also develop metastasis to the mediastinal lymph nodes in weeks 12-16. We used this model to test the hypothesis that vimentin loss prevents lung cancer metastasis by crossing this GEMM with a Vim-/- mouse to create a novel LSL-KrasG12D, LKB1fl/fl, Vim-/- (termed here KLV-/-) mouse. Our findings show that in the KLV-/- mouse, primary tumor burden and cell proliferation were not significantly different than wild-type KLV+/+ mice; however, KLV-/- mice exhibit significantly less metastasis to the mediastinal lymph nodes compared to their wild type counterpart indicating that vimentin contributes to the metastatic cascade. Consistent with this finding, histological analysis of the primary tumors show that KLV-/- mice exhibit less focal invasion than KLV+/+ and +/- mice, further confirming that KLV-/- mice have reduced invasiveness. Interestingly, vimentin staining in invasive regions of KLV+/+ mice was not found in the cancer cells but rather in fibroblast-like cells surrounding invasive cell buds that we term collective invasion packs (CIPs). These fibroblast-like, vimentin-positive cells also stain positive for alpha smooth muscle actin, which is consistent with cancer-associated fibroblasts (CAFs). Taken together, these results suggest that in this highly metastatic genetic background, vimentin may play a central role in recruiting CAFs to invading cancer cells but not necessarily in cancer cell epithelial to mesenchymal transition (EMT).
Citation Format: Alessandra M. Salgueiro, Melissa Gilbert-Ross, Lauren S. Havel, John Shupe, Allyson E. Koyen, Hans E. Grossniklaus, Gabriel Sica, Adam I. Marcus. Beyond EMT: Vimentin function in lung cancer metastasis. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr C24.
Abstract C32: The function of GPR56 in metastasis formation of melanoma
Authors: Corson Nancy , Yang Liquan , Xu Lei 
Published: October 2016

Abstract
Disseminated cancer cells often persist in tissues for a long period before being manifested as clinically detectable metastases. This metastasis dormancy imposes a main threat for cancer patients, especially after their first line of cancer treatment. Little is known as to how this dormancy is maintained and what triggers its awakening, but tumor microenvironment is thought to play a decisive role. We discovered that a member of newly described family of adhesion G protein-coupled receptors (GPCRs), GPR56, inhibits metastasis formation of melanoma cell lines and sequesters them at a dormant state in lung. GPR56 binds to TG2, a component in extracellular matrix (ECM) that could also function as a cross linking enzyme. It is significantly up-regulated in human melanoma metastases relative to the primary tumors and its expression promotes metastasis formation of melanoma cells in the experimental metastasis model. The down-regulation of TG2 by GPR56 may abolish the pro-metastasis function of TG2 in melanoma cells via destabilizing ECM and contribute to their sequestration at the dormant state. Furthermore, RNAseq analyses suggest that GPR56 may regulate the expression of factors involved in cellular homeostasis. It is thus possible that GPR56 maintains metastasis dormancy in melanoma by down-regulating TG2 in ECM and perturbing cellular homeostasis.
Citation Format: Nancy Corson, Liquan Yang, Lei Xu. The function of GPR56 in metastasis formation of melanoma. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr C32.
Abstract C39: High-content screening to capture tumor dynamics in response to microenvironmental perturbations
Authors: Garvey Colleen M. , Chen Oscar , Foo Jasmine , Mumenthaler Shannon M. 
Published: October 2016

Abstract
Tumor populations are in constant flux as a result of dynamic pressures of their surrounding microenvironment. Measuring the phenotypic response of multiple cell types exposed to physiological relevant tumor conditions has been a challenge due to the heterogenous nature of the tumor microenvironment. Further, traditional cell biology assays for assessing cell viability do not allow for additional downstream analyses and use surrogate measures for cell number, which may fail to provide a complete picture of cellular events. Here, we present a method to utilize high-content screening to generate quantitative, robust data sets characterizing cellular phenotypic responses (i.e. birth, death, morphology) of tumor cells to co-occurring perturbations of drug, oxygen, glucose, ECM stiffness, and stromal cell co-culture. Using an Operetta high-content imaging platform, we are able to perform multiple analyses on the same experimental setup to quantitatively assess the evolutionary dynamics of heterogenous cell populations under multiple environmental perturbations. We are able to differentiate between the effect of microenvironmental conditions on a decrease in cell birth versus increase in cell death, which has significant implications for predicting tumor growth kinetics and drug treatment response. We applied this platform to analyze isogenic lung tumor cells that are either sensitive or resistant to erlotinib, a commonly used tyrosine receptor kinase inhibitor in the treatment of lung cancer. We identified specific microenvironmental contexts where the resistant populations have a fitness advantage over the sensitive population, irrespective of the resistance mechanism. Furthermore, our experimental workflow allows us to capture and quantify cell morphology, an additional measure for overall cell health. We observed significant shifts in specific cell morphological parameters in response to alterations in tumor microenviromental conditions such as low oxygen and increased drug concentration. This novel application of a high-content screening platform allows for the quantification of multiple cellular phenotypes in response to over a hundred different microenvironmental contexts, thus providing deeper insight into the effect of tumor microenvironmental heterogeneity on evolving tumor cell populations.
Citation Format: Colleen M. Garvey, Oscar Chen, Jasmine Foo, Shannon M. Mumenthaler. High-content screening to capture tumor dynamics in response to microenvironmental perturbations. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr C39.
Abstract C40: Pancreatic cancer and stroma cell cross-talk affects cell proliferation in a 3D spheroid co-culture model
Authors: Norberg Jessica K. , Nania Salvatore , Heuchel Rainer L. , Löhr Matthias J. 
Published: October 2016

Abstract
Aim of the study: The aim of this study was to validate a novel 3D spheroid co-culture model of pancreatic ductal adenocarcinoma (PDAC) cells and pancreatic stellate cells (PSCs), and to use said model as to investigate the effects of PDAC cell and PSC cross-talk on cell proliferation, cell death, migration and chemo-resistance.
Methods: An eGFP-positive PSC line and PDAC cell lines were cultured in 3D spheroid mono- and co-cultures. Activation of the PSCs within the co-culture model was investigated by real time PCR for whole spheroids and spheroid populations sorted by fluorescence activated cell sorting (FACS). To investigate cell proliferation the cell numbers within the cultures were followed over time and the proportions of the different cell types within the co-cultures were monitored by FACS.
Results: The mRNA expression of the PSC activation marker ASMA as well as the ECM proteins collagen I, laminin and lumican, the PDGFbeta receptor (PDGFRb) and the transforming growth factor beta1 (TGFb-1) downstream effector connective tissue growth factor (CTGF), were increased in PSCs within co-cultures compared to mono-cultures. PSCs were initially expanding but then diminished within 3D spheroid co-cultures together with two separate PDAC cell lines (Panc-1 and HPAF-II). Panc-1 cell numbers were seemingly unaffected by the presence of PSCs, but with higher proportions of PSCs the Panc1 cell numbers within the co-cultures initially were lagging behind but then caught up to the numbers within the mono-cultures. This growth switch was correlated with the opposite switch seen for the PSCs. The proliferation of HPAF-II cells, was on the other hand induced within the co-cultures compared to mono-cultures.
Conclusions: PSCs are activated within the 3D spheroid co-cultures. Both tumor cell and PSC proliferation is influenced by co-culturing the cells in the 3D spheroid model. Different PDAC cell – PSC combinations are affected differently. We currently are investigating the effects on cell death and apoptosis, migration and chemo-resistance.
Citation Format: Jessica K. Norberg, Salvatore Nania, Rainer L. Heuchel, Matthias J. Löhr. Pancreatic cancer and stroma cell cross-talk affects cell proliferation in a 3D spheroid co-culture model. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr C40.
Abstract C42: DNA methyltransferase 1 (Dnmt1) is a key regulator of TGFβ-mediated endothelial-to-mesenchymal transition
Authors: Xiao Lin , Dudley Andrew C. 
Published: October 2016

Abstract
Cancer-associated fibroblasts (CAFs) are prominent in the tumor microenvironment and they fuel tumor angiogenesis, tumor growth, and metastasis. CAFs are identified by smooth muscle actin and type collagen 1 expression, they promote intratumoral desmoplasia and fibrosis, and they are derived from multiple cellular precursors including tumor endothelial cells (TECs) through a TGFβ-regulated process termed endothelial-to-mesenchymal transition (EndMT). Recently, we uncovered two distinct TEC populations: TGFβ-responders that undergo rapid EndMT accompanied by CAF marker up-regulation in response to TGFβ and TGFβ non-responders that are comparatively resistant to TGFβ-induced EndMT. From a biochemical screen, we found that 5-Azacytidine, a small-molecule inhibitor of DNA methyltransferases (DNMTs), converts TGFβ non-responders into responders suggesting that TGFβ responsiveness is dictated by epigenetic mechanisms. siRNA silencing of Dnmt1 is sufficient to promote TGFb-induced EndMT in non-responders, whereas Dnmt3a or Dnmt3b are not involved. Chronic (&gt; 7 days) TGFβ stimulation also suppresses Dnmt1 expression and drives the conversion of non-responders into responders indicating that TGFβ may un-silence CAF-specific genes in TECs in part by antagonizing DNMT1 expression/activity. Our findings shed light on the epigenetic mechanisms that regulate TGFβ- and EndMT-mediated conversion of TECs into CAFs. Targeting these mechanisms could inhibit tumor growth and spread.
Citation Format: Lin Xiao, Andrew C. Dudley. DNA methyltransferase 1 (Dnmt1) is a key regulator of TGFβ-mediated endothelial-to-mesenchymal transition. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr C42.
Abstract IA02: Immune checkpoint blockade in cancer therapy: New insights and opportunities, and prospects for cures
Authors: Allison James P. 
Published: October 2016

Abstract
The existence of multiple non-redundant inhibitory pathways that limit T cell responses offers novel strategies for mobilizing the immune system to attack cancer cells. The best characterized of these immune checkpoints is CTLA-4, which inhibits T cell proliferation by interfering with the interaction of the costimulatory molecule CD28 with its ligands B7-1 and B7-2 on the surface of antigen presenting cells. Antibodies to CTLA-4 have proven effective against multiple tumor types in both pre-clinical and clinical studies. Ipilimumab, an antibody to human CTLA-4, showed long term (&gt;4 years) survival benefit in about 20% of patients in a randomized, placebo-controlled trial in late stage melanoma. A follow up study of almost 5,000 patients showed that 22% were alive 10 years after treatment disease.
The mechanism(s) of action of anti-CTLA-4 are still being elucidated. We and others have shown that CLTA-4 limits T cell proliferation by a cell intrinsic mechanism. However, there is also evidence that anti-CTLA-4 has to engage the target on both effector (Teff) and regulatory (Treg) T cells. Thus anti-CTLA-4 exerts its anti-tumor effects by multiple mechanisms.
PD-1, another checkpoint, recruits a phosphatase and seems to interfere with T cell antigen receptor mediated signaling. It has two ligands, PD-L1 and PD-L2, which are both expressed on dendritic cells. However, many tumor cells also express PD-L1. Antibodies to PD-1 and PD-L1 have both shown objective responses against several tumor types in clinical trials with response rates of about 25% . A recent phase III trial of a combination of anti-PD-1 and anti-CTLA-4 in melanoma showed objective responses in about 50% of late stage melanoma patients.
To date the US Food and Drug administration has issued 8 approvals for antibodies targeting CTLA-4 or PD-1 in a variety of indications, including melanoma, lung, and kidney cancer.
Emerging data suggest that T cell responses are largely directed toward neoantigens arising as a result of mutational events associated with the carcinogenesis. While all tumors with antigens recognizable by the immune system should be targets for checkpoint blockade, it is becoming clear that certain types of tumors with lower burdens of mutations (eg. prostate, breast, and kidney cancer) present special challenges for immune therapy. Strategies for effective treatment of such tumors will be discussed.
Citation Format: James P. Allison. Immune checkpoint blockade in cancer therapy: New insights and opportunities, and prospects for cures. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr IA02.
Abstract IA10: Convergent control of cancer associated fibroblast activation and field cancerization by Notch/CSL and p53 signaling
Authors: Dotto G. Paolo , Dotto G. Paolo 
Published: October 2016

Abstract
The vast majority of epithelial cancers is limited to in situ lesions that, for internal organs like breast, prostate or lung, can remain undetected for the whole life of an individual. The reason(s) why only a minor fraction of these lesions progresses into malignancy is not understood. Changes in tumor stroma are most frequently viewed as secondary to changes in the epithelium. However, recent evidence indicates that they may play a primary role. Such a possibility would help explain not only dormancy of most epithelial cancers, but also field cancerization, a condition of major clinical significance linked with multifocal and recurrent tumors and broader tissue changes beyond areas of tumor development that expand over time.
Stromal fibroblast senescence has been linked to aging-associated cancer risk. However, density and proliferation of cancer associated fibroblasts (CAF) are frequently increased. In the mouse, deletion of the Notch effector CSL/RBP-Jκ in dermal fibroblasts is sufficient for CAF activation and ensuing multifocal keratinocyte tumors. We report that CSL silencing induces senescence of primary fibroblasts of both mouse and human origin, and from dermis, oral mucosa, breast and lung. CSL functions in these cells as direct repressor of multiple senescence- and CAF-effector genes. It also physically interacts with p53, repressing its activity. CSL is down-modulated in stromal fibroblasts of premalignant skin actinic keratosis lesions and squamous cell carcinomas (SCC), while p53 expression and function is down-modulated only in the latter, with paracrine FGF signaling as likely culprit. Concomitant loss of CSL and p53 overcomes fibroblast senescence, enhances expression of CAF effectors and promotes stromal and cancer cell expansion. The findings support a CAF activation/stromal co-evolution model under convergent CSL/p53 control.
Citation Format: G. Paolo Dotto, G. Paolo Dotto. Convergent control of cancer associated fibroblast activation and field cancerization by Notch/CSL and p53 signaling. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr IA10.
Abstract IA14: Breaking bad: Cancer-associated fibroblasts are reprogrammed from growth inhibitory to pro-inflammatory and tumor promoting in breast cancer
Authors: Sharon Yoray , Ershaid Nour , Raz Yael , Cohen Noam , Pasmanik-Chor Metsada , Geiger Tamar , Erez Neta 
Published: October 2016

Abstract
Breast tumors are characterized by an extensive desmoplastic stroma, abundantly populated by fibroblasts. We previously demonstrated that Cancer-Associated Fibroblasts (CAFs) orchestrate tumor-enhancing inflammation in multiple mouse and human malignancies, including breast cancer. Although breast cancer is one of the major tumor types where CAFs were shown to be tumor promoting, there is no detailed analysis of the dynamic changes in CAFs characteristics and function in correlation with tumor progression. We therefore set out to characterize the dynamic changes in CAFs during progression of mammary carcinogenesis, in a transgenic mouse model of human breast cancer. We profiled the transcriptome of fibroblasts isolated from normal mammary glands, or from mammary glands of transgenic mice at defined tumorigenic stages. Data analysis revealed unique CAF gene signatures that correspond to distinct tumor stages, with only partial overlap between the stages, suggesting co-evolution of the microenvironment with tumorigenic progression. Interestingly, the gene signature of fibroblasts isolated from hyperplastic lesions is inverse to that in CAFs from neoplastic stages, and has a growth inhibitory phenotype, while CAFs from mammary tumors express pro-inflammatory and tumor promoting gene signatures. Moreover, we functionally demonstrate that CAFs isolated from late carcinoma express a gene signature that links tissue damage with tumor-promoting inflammation. To identify tumor-secreted factors capable of reprogramming normal mammary fibroblasts to pro-inflammatory CAFs, we performed a proteomic screen of breast cancer cells secretome, and identified Osteopontin (OPN). Knockdown of OPN in tumor cells in vivo resulted in attenuated stromal activation, reduced immune cell recruitment and inhibition of tumor growth. Taken together, our findings reveal reciprocal crosstalk between fibroblasts and cancer cells which drives CAF reprogramming, to facilitate tumor progression in breast cancer.
Citation Format: Yoray Sharon, Nour Ershaid, Yael Raz, Noam Cohen, Metsada Pasmanik-Chor, Tamar Geiger, Neta Erez. Breaking bad: Cancer-associated fibroblasts are reprogrammed from growth inhibitory to pro-inflammatory and tumor promoting in breast cancer. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr IA14.
Abstract IA18: Latency and immune evasion of metastatic stem cells
Authors: Massagué Joan 
Published: October 2016

Abstract
Metastasis frequently develops years after the removal of a primary tumor, from a minority of disseminated cancer cells that survived as latent entities. An improved understanding of the location and survival mechanisms of disseminated cancer cells, and their ability to enter a quiescent state, evade immune surveillance, and retain tumor reinitiating capacity is needed to better prevent and treat metastatic cancer. To this end, we isolated latency competent cancer (LCC) cells from early-stage human lung and breast carcinoma cell lines and defined the mechanisms that prevent the outgrowth, support the long-term survival, and maintain the tumor-initiating potential of these cells during latent metastasis. LCC cells show stem cell-like characteristics and express Sox transcription factors, which are essential for their survival in host organs under restrictive conditions and for metastatic outgrowth under permissive conditions. Through autocrine suppression of WNT signaling and heightened TGF-β signaling, LCC cells self-impose a slow-cycling state with broad down-regulation of NK cell activators. By actively entering quiescence, these metastatic stem cells can evade innate immunity to remain latent for extended periods.
Citation Format: Joan Massagué. Latency and immune evasion of metastatic stem cells. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr IA18.