tbuckley/cabot-search huggingface dataset:
Abstract A043: Senescent CAFs modulate tumor immunity and promote breast cancer progression
Authors: Jiayu Ye, John M. Baer, Douglas V. Faget, Vasilios A. Morikis, Qihao Ren, Anupama Melam, Ana Paula Delgado, Erik Knudsen, Agnieszka Witkiewicz, Robert S. Powers, Gregory D. Longmore, David G. DeNardo, Sheila A. Stewart
Journal: Cancer Research (2024)

Abstract Cellular senescence is characterized by a series of markers such as p16INKA4(p16) positivity and a distinctive profile of secretory factors including mitogens, cytokines, and extracellular matrix (ECM) proteins that are collectively recognized as senescence-associated secretory phenotype (SASP). Interestingly, high p16 positivity in stroma strongly correlates with ductal carcinoma in situ (DCIS) recurrence, raising the possibility that p16+ senescent stromal cells contribute to breast cancer progression. To explore the hypothesis, we carried out single-cell RNA sequencing (scRNA-seq) analyses of murine and human HER2+/ER+/TNBC tumor samples and found that senescence was restricted to a specific cancer-associated fibroblasts (CAF) subpopulation that expresses numerous SASP factors that could impact tumor immunosurveillance, including cytokine SASP factors and ECM SASP factors such as collagens. We refer to these cells as senescent CAFs (senCAFs). To investigate how senCAFs impact tumorigenesis, we crossed MMTV-PyMT (PyMT) mice that spontaneously develop mammary tumors to INK-ATTAC (INK) mice, which allows selective elimination of p16+ senescent cells. Depletion of senCAFs in PyMT/INK mice led to significantly delayed tumor onset and changes in various tumor-infiltrating immune cells including natural killer (NK) cells, both of which could be recapitulated by treating PyMT mice with a senolytic drug. Monoclonal antibody- mediated NK cell depletion in the PyMT model further indicated that NK cells are indispensable for senCAF’s tumor-promoting effect. Finally, our bulk RNA-sequencing and cytotoxicity assays revealed that ECM derived from senescent but not cycling myofibroblastic mammary fibroblasts potently inhibited NK cell killing of tumor cells. Importantly, PyMT mice treated with Losartan (DuP-753), an inhibitor for collagen I synthesis, showed lower tumor burden and improved tumor-infiltrating NK cell status. Together our data highlight that senCAFs contribute to mammary gland tumorigenesis by modulating tumor ECM and immunity and suggest that senolytic treatment may limit breast cancer progression. Citation Format: Jiayu Ye, John M. Baer, Douglas V. Faget, Vasilios A. Morikis, Qihao Ren, Anupama Melam, Ana Paula Delgado, Erik Knudsen, Agnieszka Witkiewicz, Robert S. Powers, Gregory D. Longmore, David G. DeNardo, Sheila A. Stewart. Senescent CAFs modulate tumor immunity and promote breast cancer progression [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A043.
Abstract B019: Regulatory macrophages contribute to tumor cell plasticity in colorectal cancer metastases
Authors: Matthew A. Cottam, Muhammad B. Mirza, Emily N. Arner, Marium Siddiqui, Clare Lipscombe, Zaid Hatem, Katy E. Beckermann, Kamran Idrees
Journal: Cancer Research (2024)

Abstract Metastatic disease is the common cause of death in colorectal cancer. To better understand the cellular landscape of colorectal metastasis, we profiled primary tumors and liver, lung, and peritoneal metastases using single-cell RNA sequencing. Our analysis revealed a subset of tumor epithelial cells with a highly plastic transcription profile and, inversely, low expression of stemness markers. Tumor cells with plasticity markers were spatially enriched at the tumor- stroma interface with exposure to tissue microenvironmental factors. Cell-free malignant ascites, which recapitulates the tumor microenvironment, impaired expression of proliferation and stem- like markers in favor of plasticity markers and enhanced migration of tumor cells. Furthermore, Co-culture of colorectal tumor cells with CD11b+ macrophages isolated from malignant ascites from patients was sufficient to recapitulate tumor cell plasticity. Profiling of tumor-associated macrophages identified enrichment for a lipid-handling features and high spatial correlation with plastic tumor cells. Taken together, we demonstrate that tumor-associated macrophages contribute to disease progression through development of pro-malignant features. Citation Format: Matthew A. Cottam, Muhammad B. Mirza, Emily N. Arner, Marium Siddiqui, Clare Lipscombe, Zaid Hatem, Katy E. Beckermann, Kamran Idrees. Regulatory macrophages contribute to tumor cell plasticity in colorectal cancer metastases [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B019.
Abstract A018: Endothelial pyrimidine synthesis deficiency promotes tumor growth
Authors: Petra Hyrossova, Isidora Milisav, Silvia Novais, Mirko Milosevic, Jakub Rohlena, Katerina Rohlenova
Journal: Cancer Research (2024)

Abstract The tumor microenvironment plays a crucial role in cancer progression and treatment response. Systemically administered metabolic cancer therapies target not only malignant but also stromal cells, including immune cells - the only stromal population previously addressed in this context. However, how such treatments impact other non-malignant cell types in tumors remains poorly understood. Here we show that inhibition of de novo pyrimidine synthesis in endothelial cells accelerates tumor growth and alters tumor immune repertoire. We found that whole-body de novo pyrimidine synthesis deficiency in mice, caused by the inducible whole-body ablation of DHODH, accelerates the growth rate of orthotopic lung tumors. Single-cell transcriptomic analysis of tumor-bearing lungs revealed that DHODH deficiency in the stroma impacts multiple cell populations, including immune and, surprisingly, endothelial cells. To explore the endothelial-specific effects, we generated a mouse model with inducible DHODH deficiency restricted to endothelial cells. The endothelium-specific model recapitulates the accelerated lung tumor growth observed in the whole-body DHODH deficiency model. Single-cell transcriptomics analysis of tumor-bearing lungs in the endothelium-specific model pointed to changes in the immune repertoire, particularly an enrichment of monocytes. We confirmed these results on the protein level using spectral flow cytometry, and we are currently in the process of uncovering the mechanism by which endothelial deficiency of pyrimidine synthesis affects the immune landscape of tumors. Inhibitors of pyrimidine de novo synthesis have been tested in clinical trials but failed due to their low efficiency. Our findings indicate that systemic treatment targeting pyrimidine synthesis may be hampered by its pro-tumorigenic effects in the endothelium, highlighting the unexpected role of endothelial metabolism in this context. Citation Format: Petra Hyrossova, Isidora Milisav, Silvia Novais, Mirko Milosevic, Jakub Rohlena, Katerina Rohlenova. Endothelial pyrimidine synthesis deficiency promotes tumor growth [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A018.
Abstract A003: The role of aging in promoting immune mediated reactivation from metastatic melanoma dormancy
Authors: Kelly Coutant, Jhon Passamonte, Christopher Price, Pulkit Datt, Mitchell Fane
Journal: Cancer Research (2024)

Abstract Metastasis is the primary cause of melanoma death. A major problem with the vast majority of previous studies is that young mice (8-weeks old, equivalent to 20 human years) are used to investigate the mechanisms of metastatic outgrowth, whereas the median age of melanoma diagnosis in humans is ∼65 years. Advanced age also correlates with metastasis, mortality, and immune dysfunction. Moreover, most studies often only focus on lung metastases, despite melanoma commonly metastasizing to sites such as the liver in patients, which are significantly more resistant to checkpoint inhibitors (ICIs) compared to patients with lung metastases. We have begun addressing these core limitations by developing novel syngeneic mouse models of melanoma metastasis and colonization in young (8-week), middle-aged (12-month), and geriatric (18-22 month) mice, in which metastatic colonization/dissemination can be targeted to either the lung or liver alone, or to both simultaneously. Our data now show that aging promotes reactivation of dormant tumor cells and subsequent outgrowth of lung and liver metastases. We have found that frontline innate lymphocytes such as NK-cells and γδ T-cells are decreased in the pre-metastatic lung and livers of aged mice relative to young mice and remain decreased during early and late-stage metastasis. Using inducible KO mouse models and antibody depletion methods in young growth restrictive mice, we find that depletion of either NK-cells or γδ T-cells is sufficient to promote reactivation from dormancy and resistance to anti-PD1 therapy. Secondly, we further delineated changes in the post-metastatic lung and liver niche. We find that PROS1 secretion by reactivated melanoma cells expressing high levels of the MER tyrosine kinase receptor (MER) in the aged metastatic lung and liver increases CD11b myeloid cells expressing the immunosuppressive factor ARG1. Within this CD11b subset, we see an increase in polymorphonuclear myeloid derived suppressor cells (PMN MDSCs). Treatment with recombinant ARG1 promotes reactivation from dormancy in young mice whilst depletion of PMN MDSCs inhibits age induced outgrowth in the lung and liver. Overall, our study highlights common immune-mediated age-related changes in the pre and post metastatic lung and liver which contribute to aggressive metastatic initiation, reactivation from dormancy, progression, and resistance to anti-PD1 Citation Format: Kelly Coutant, Jhon Passamonte, Christopher Price, Pulkit Datt, Mitchell Fane. The role of aging in promoting immune mediated reactivation from metastatic melanoma dormancy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A003.
Abstract A014: Effects of senescence on the lung tumor microenvironment
Authors: Luis Prieto
Journal: Cancer Research (2024)

Abstract Despite progress in screening and treatment, lung cancer remains the leading cause of cancer- related deaths worldwide. An overarching issue is the complexity and heterogeneous nature of the tumor microenvironment and eventual tumor spread. While aging is a key determinant, the relationship between aging and cancer is multi-faceted and extends beyond the accumulation of mutations. Therefore, a much-needed framework integrating the mechanistic principles that change with aging to drive neoplastic transformation beyond genetics will help us uncover predictive biomarkers that inform treatment decision-making and how we may use them to prevent, postpone, suppress tumor growth, and limit spread. Here, we investigate the role of age-related senescent cell accumulation in lung tumorigenesis and propose a potential strategy to delay tumor progression and spread by selectively targeting tumor-promoting senescent cells that arise with increasing age to sustain protective antitumor immunity. Citation Format: Luis Prieto. Effects of senescence on the lung tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A014.
Abstract A009: PIEZO1 driven tumor aggressiveness in an organ-on-chip model of colorectal cancer
Authors: Curran A. Shah, Carly R. Strelez, Aaron Schatz, Hannah Jiang, Rachel Perez, Shannon M. Mumenthaler
Journal: Cancer Research (2024)

Abstract Mechanical forces have long been known to affect the progression of cancer, however exact study of the specific consequences of these forces has been hampered by currently available model systems. Traditional cell culture models often lack the ability to incorporate physiologically relevant mechanical forces, and animal models offer too much complexity to be able to effectively isolate and study the mechanical forces. Organ-on-chip (OOC) technology allows for the integration of human relevant physiological forces in a setting conducive to their study. Here, we explore how the early metastatic spread of colorectal cancer (CRC) can be influenced by physiological mechanical forces. Specifically, we investigated the ability of peristaltic motions, responsible for natural bowel motility, to enhance the invasive capability of colon tumor cells. Our microfluidic OOC model comprises of an epithelial channel and endothelial channel separated by a porous membrane allowing for biological and chemical crosstalk between them. Vacuum channels spanning the length of the structure allow force to applied in a cyclic manner mimicking peristaltic contraction and relaxation. Our OOC model supports the addition of tumor microenvironment (TME) components in a piece-wise manner to better understand how specific factors influence the behavior of tumor cells. Analyzing gene and protein expression levels, we have found that peristaltic-like motions induce changes in the Hippo signaling and epithelial-to-mesenchymal (EMT) pathways resulting in greater invasion of tumor cells into the endothelial compartment as observed by on-chip confocal imaging. Moreover, knock down studies have demonstrated that the response to peristaltic-like stretch is driven through a PIEZO1-mediated mechanism. Furthermore, to increase the physiological relevance of our model, we administered peripheral blood mononuclear cells (PBMCs) to the endothelial channel to simulate aspects of the immune TME. Preliminary studies revealed that the recruitment of PBMCs can be altered by the presence of peristaltic-like stretch. Our findings demonstrate that mechanical forces in the CRC TME can dramatically alter tumor behavior as shown in our CRC-OOC model. Citation Format: Curran A. Shah, Carly R. Strelez, Aaron Schatz, Hannah Jiang, Rachel Perez, Shannon M. Mumenthaler. PIEZO1 driven tumor aggressiveness in an organ-on-chip model of colorectal cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A009.
Abstract B014: NRF2 regulation of the immune microenvironment in breast cancer
Authors: Yasemin Ceyhan Ozdemir, James V. Alvarez
Journal: Cancer Research (2024)

Abstract Immune checkpoint inhibitors (ICIs) have emerged as a significant advance in the treatment of various cancer types, including breast cancer, though their efficacy varies widely depending on the cancer subtype and the stage of the disease. Following their initial approval in metastatic triple-negative breast cancer (TNBC), ICIs have shown promising results in other contexts, including early-stage cancers and ER+ and HER2+ subtypes. However, even in advanced TNBC the objective response rate to monotherapy ICI is only ∼20%. These results highlight the need to better understand determinants of ICI response in breast cancer. A detailed, high-resolution definition of the tumor immune microenvironment (TIME) will be critical for predicting and engineering effective responses to ICIs. In previously published work, we and others found that the antioxidant transcription factor NRF2 is constitutively active in breast cancer and is associated with tumor recurrence, metastasis, and poor prognosis. However, the mechanisms through which NRF2 promotes breast cancer progression remain unclear. In the current study, we explore the role of NRF2 in reshaping the TIME and its impact on breast cancer progression using preclinical models, flow cytometry, and transcriptomic analyses. We find that NRF2 is constitutively activated in a subset of human and mouse breast cancers where it functions to suppress inflammatory gene expression. In models of recurrent and metastatic mammary tumors, NRF2 knockdown results in a marked reduction in tumor growth rates. Furthermore, the NRF2 inhibition significantly alters the composition of innate and adaptive immune cell populations within the tumor microenvironment. Cytokine profiling revealed that these immune alterations are associated with increased levels of inflammatory cytokines in NRF2-deficient tumor cells compared to controls. RNA sequencing of tumor cells further supports the observed shifts in the immune landscape associated with NRF2 deficiency. Collectively, our findings demonstrate that the loss of NRF2 impairs tumor growth in part through remodeling the TIME and suggest that NRF2 may be a promising therapeutic target for sensitizing breast cancers to ICIs. Citation Format: Yasemin Ceyhan Ozdemir, James V. Alvarez. NRF2 regulation of the immune microenvironment in breast cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B014.
Abstract A032: Uncovering the impact of current therapies on LUAD dormant metastasis
Authors: Inês Godet, Zhenghan Wang, Joan Massagué
Journal: Cancer Research (2024)

Abstract Despite recent therapeutic advances, Lung Adenocarcinoma (LUAD) remains a leading cause of mortality worldwide, with most deaths attributed to metastasis. Metastasis is mediated by disseminated metastasis initiating cells (MICs) that can persist in a dormant state in distant sites for months to years and ultimately drive metastatic relapse, which is clinically incurable. Adjuvant therapy seeks to prevent cancer relapse, however, efforts to improve adjuvant treatments are hindered by an insufficient understanding of the molecular mechanisms supporting the long-term viability of dormant MICs. We have established that primitive LUAD cells characterized by the spontaneous expression of the pluripotency transcription factor SOX2 can enter an immune-evasive dormant state with downregulation of immune response mediators (STING, NK ligands, MHC-I) to evade immune surveillance during dormancy. Now, we hypothesize that dormant and immune evasive progenitor MICs may also escape therapies targeting growth pathways. We have generated latency competent cells (LCCs) that can remain in a latent state for months by isolating progenitor cells from the Kras LSL-G12D/+ ;Trp53 flox/flox mouse model and screening their metastatic potential and progenitor state in the B6 background. LCCs entering a slow-cycling state in response to dormancy signals remain sensitive to targeted KRAS inhibitors but contain a resistant subpopulation that survives. To specifically characterize the progenitor state in these LCC populations, we have developed and validated two strategies to fluorescently mark SOX2 expression and activity, respectively. As speculated, the resistant population is mostly composed of SOX2+ progenitor LCCs after treatment with KRAS inhibitor under dormancy signaling. Furthermore, induced-dormancy also drives an accumulation of cells in the SOX2+ progenitor state in these LCC-rich populations. Ongoing studies are focused on delineating the emergence of the SOX2+ progenitor state in LCCs during dormancy and the biological mechanisms driving their persistence and resistance to targeted therapies. We aim to define (1) the dependence of dormant LCCs on oncogenic signaling, the (2) effect of targeted therapy on MICs, and (3) strategies to overcome potential resistance mechanisms in dormant MICs. Our ultimate goal is to delineate strategies to clear latent MICs and prevent LUAD recurrence. Citation Format: Inês Godet, Zhenghan Wang, Joan Massagué. Uncovering the impact of current therapies on LUAD dormant metastasis [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A032.
Abstract A023: Arachidonic acid metabolism promoting cross resistance in melanoma cells
Authors: Casey D. Stefanski, Daniel A. Erkes, Timothy J. Purwin, Glenn L. Mersky, Erica L. Kitterman, Manal Mustafa, Jelan Haj, Diana Melissaratos, Andrew E. Aplin
Journal: Cancer Research (2024)

Abstract Melanoma patients initially respond well to first line immunotherapy. However, cross resistance to immunotherapy and BRAF/MEK inhibitor is a clinical challenge for melanoma care. To investigate drug tolerant and resistant mechanisms promoting cross resistance, we analyzed RNA-sequencing and gene set enrichment targeted therapy resistant melanoma cells revealing an enriched arachidonic acid gene signature. Intracellular arachidonic acid levels were increased in drug resistant and drug tolerant melanoma models. Arachidonic acid is enzymatically converted by COX1 and COX2 to prostaglandins, which is subsequently secreted into the microenvironment. Drug tolerant and resistant cells had increased protein expression of COX1 and COX2 concurrently with increased secretion of prostaglandin E2. COX1/2 inhibition and COX2 knockdown in vitro had no effect on cell growth in drug tolerant or resistant cells compared to parental cells. However, secreted prostaglandins are known immunomodulators, thus we explored how COX1/2 inhibition in combination with BRAF inhibitor plus MEK inhibitor affected immune cell infiltration. COX1/2 inhibition increased CD4+ and CD8+ T cell infiltration as compared to BRAF inhibitor plus MEK inhibitor alone. Under constant BRAF inhibitor plus MEK inhibitor treatment, we found that COX1/2 inhibition upon reaching MRD status prevented tumor relapse in vivo and increased survival dependent on an immune system. Future studies will evaluate the importance of arachidonic acid metabolism in promoting cross resistance to immune checkpoint blockade and whether T cell depletion prevents the delayed tumor relapse. Overall, COX1/2 inhibition delayed tumor relapse and survival in an immune-dependent manner and demonstrated a potential cross resistant mechanism. Citation Format: Casey D. Stefanski, Daniel A. Erkes, Timothy J. Purwin, Glenn L. Mersky, Erica L. Kitterman, Manal Mustafa, Jelan Haj, Diana Melissaratos, Andrew E. Aplin. Arachidonic acid metabolism promoting cross resistance in melanoma cells [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A023.