tbuckley/cabot-search huggingface dataset:
Abstract C024: MPLA+IFNg-activated tumor-associated macrophages alter fibroblast composition
Authors: Lijuan Sun, Bodu Liu, Yixin Zhao, Mikala Egeblad
Journal: Cancer Research (2024)

Abstract In a previous study, we developed a strategy to reprogram tumor-associated macrophages (TAMs) and induce a collaborative innate-adaptive immune response by combining monophosphoryl lipid A (MPLA) with IFNγ. However, we also observed downregulation of extracellular matrix (ECM)-associated genes in MPLA+IFNγ-treated mammary tumors, indicating that the combination treatment impacts the tumor microenvironment beyond just the immune cells. In this study, we investigated how MPLA+IFNg treatment modulates the tumor ECM, with a particular focus on fibroblasts-the major ECM-producing cells. Using scRNA-seq to profile mammary carcinomas, we identified six macrophage populations (C1q+, Ccr2+, Spp1+, Lyz+, mt+ and ki67+ TAMs) and two fibroblast populations (Cd34+ and a-SMA+ fibroblasts) in MMTV-PyMT tumor. MPLA+IFNγ treatment increased the numbers and percentages of Lyz+ TAMs and Cd34+ fibroblasts, while the numbers and percentages of Spp1+ TAMs and α-SMA+ fibroblasts were decreased by the treatment. Thus, MPLA+IFNγ treatment induced significant changes in both macrophage and fibroblast populations. Further analysis revealed an unusual gene expression pattern in Lyz+ TAMs. Mgst1 and Gng12 expression was detected in Lyz+ TAMs at levels comparable to those in fibroblasts, despite these genes typically being expressed in fibroblasts but not in macrophages of normal human tissues. However, to our surprise, MPLA+IFNγ treatment did not significantly increase Mgst1 and Gng12 expression of mono-cultured TAMs or bone marrow-derived macrophages, suggesting that these genes were not directly upregulated by MPLA+IFNγ treatment. Instead, the Mgst1 and Gng12 transcripts may have originated from engulfed fibroblasts. In addition, following MPLA+IFNγ treatment, more iNOS+ macrophages (which we previously identified as tumoricidal macrophages) were found in very close proximity to α-SMA+ fibroblasts. To directly test whether MPLA+IFNg-treated TAMs kill and engulf fibroblasts, we performed ex vivo co-cultures of TAMs and fibroblasts. Following MPLA+IFNγ treatment, TAMs effectively killed and engulfed the fibroblasts, whereas minimal fibroblast engulfment was observed in the control co-cultures. Our data suggest that tumoricidal MPLA+IFNγ-treated TAMs can regulate the ECM of tumors by targeting and eliminating the major ECM-producing cells, the fibroblasts. Ongoing studies are determining the functional consequences of the TAM-mediated regulation of fibroblasts and ECM composition. Citation Format: Lijuan Sun, Bodu Liu, Yixin Zhao, Mikala Egeblad. MPLA+IFNg-activated tumor-associated macrophages alter fibroblast composition [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 C024.
Abstract C029: PM2.5-induced drug resistance in lung cancer
Authors: Chi-Yuan Chen, Chieh-Wen Chan, Tong-Hong Wang
Journal: Cancer Research (2024)

Abstract Long-term exposure to PM2.5 air pollution is a significant contributor to lung cancer incidence. Our previous studies have shown that such exposure promotes lung cancer progression by activating the EGFR (epidermal growth factor receptor) and AhR (aryl hydrocarbon Receptor) pathways. We observed that in lung cancer cells with EGFR mutations, prolonged PM2.5 exposure induces EGFR activation, resulting in accelerated tumor cell growth both in vitro and in vivo. This suggests that PM2.5 may play a role in the resistance to EGFR-TKI (tyrosine kinase inhibitor) therapies, raising concerns about treatment efficacy. To explore this, we exposed the EGFR-mutant lung cancer cell line to PM2.5 for 90 days. Our results revealed that long-term exposure not only reduced the therapeutic effect of EGFR-TKIs but also increased the expression of cMyc, a gene linked to poor prognosis and drug resistance. We further confirmed that PM2.5-induced EGFR-TKI resistance is driven by the AhR-cMyc pathway. AhR, activated by environmental toxins in PM2.5, increases cMyc expression, leading to drug resistance. When we administered cMyc inhibitors, the PM2.5-exposed cells regained sensitivity to EGFR-TKI therapy. These findings indicate that targeting the AhR-cMyc pathway could be a promising approach to overcome PM2.5-induced resistance in lung cancer treatment. Further research is needed to explore the broader implications of environmental pollution on cancer therapy and to develop strategies to counteract the effects of pollutants like PM2.5. Citation Format: Chi-Yuan Chen, Chieh-Wen Chan, Tong-Hong Wang. PM2.5-induced drug resistance in lung 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 C029.
Abstract C041: MYC and p53 alterations cooperate through VEGF signaling to repress cytotoxic T cell and immunotherapy responses in prostate cancer
Authors: Katherine Murphy
Journal: Cancer Research (2024)

Abstract Patients with castration-resistant prostate cancer (CRPC) are generally unresponsive to tumor targeted and immunotherapies. Whether genetic alterations acquired during the evolution of CRPC impact immune and immunotherapy responses is largely unknown. Using our innovative electroporation-based mouse models, we generated distinct genetic subtypes of CRPC found in patients and uncovered unique immune microenvironments. Specifically, mouse and human prostate tumors with MYC amplification and p53 disruption had weak cytotoxic lymphocyte infiltration and an overall dismal prognosis. MYC and p53 cooperated to induce tumor intrinsic secretion of VEGF, which by signaling through VEGFR2 expressed on CD8+ T cells, could directly inhibit T cell activity. Targeting VEGF-VEGFR2 signaling in vivo led to CD8+ T cell-mediated tumor and metastasis growth suppression and significantly increased overall survival in MYC and p53 altered CPRC. VEGFR2 blockade also led to induction of PD-L1, and in combination with PD-L1 immune checkpoint blockade produced anti-tumor efficacy in multiple preclinical CRPC mouse models. Thus, our results identify a genetic mechanism of immune suppression through VEGF signaling in prostate cancer that can be targeted to reactivate immune and immunotherapy responses in an aggressive subtype of CRPC. Citation Format: Katherine Murphy. MYC and p53 alterations cooperate through VEGF signaling to repress cytotoxic T cell and immunotherapy responses in prostate 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 C041.
Abstract IA013: Stromal and immune plasticity shape the metastatic microenvironment
Authors: Neta Erez
Journal: Cancer Research (2024)

Abstract Mortality from cancer is almost exclusively due to metastasis to distant organs. Therefore, understanding the biology of tumor metastasis is the most significant challenge in cancer research today. The tumor microenvironment is central in supporting tumor growth. However, the role of the metastatic microenvironment in the multistage process of metastasis is largely unresolved. Since each metastatic microenvironment exerts specific functions that support or oppose colonization by disseminated tumor, understanding distinct organ-specific mechanisms that enable metastatic growth is of crucial importance. Utilizing mouse models of breast cancer metastasis to lungs, brain and bone, combined with clinical data from patients with metastatic disease, we uncover the mechanisms that underlie the early events of metastasis to provide the mechanistic basis for therapeutic targeting to reduce metastatic relapse. Our findings reveal organ-specific co-evolution of stromal and immune cells at distinct metastatic niches, that lead to the formation of an immunosuppressive microenvironment, permissive to metastatic growth. Analysis of human metastasis reveal that these pathways are also operative in human disease. We show that genetic and/or pharmacological targeting of specific nodes in the interactions between stromal and immune cells results in attenuated metastasis and improved survival. Our findings imply that combinatorial therapeutic strategies to target the crosstalk between stromal and immune cells at the metastatic microenvironment may be a promising treatment strategy to inhibit metastatic relapse. Citation Format: Neta Erez. Stromal and immune plasticity shape the metastatic 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 IA013.
Abstract C019: IL27R signaling regulates neutrophils maturation, activation and function in colorectal cancer-liver metastases
Authors: Jiani Zhu, Zhengzheng Shi, Ekaterina Koltsova
Journal: Cancer Research (2024)

Abstract Colorectal cancer (CRC) is the third most common cancer and fourth cause of cancer death worldwide. The liver is the most common organ for CRC metastasis, which is a major cause of death for CRC patients. Therefore, a better understanding of mechanisms facilitating CRC liver metastasis is in urgent need. IL27 is a member of IL6/IL12 cytokines superfamily which have a critical role in tumor microenvironment to affect tumorigenesis and metastasis. IL27 is secreted by activated macrophages and dendritic cells, and IL27R is expressed in various immune cells, mediating IL27-dependent pro-inflammatory or anti-inflammatory immune responses. However, the role of myeloid IL27 signaling in CRC-liver metastasis remains unclear. To study the role of IL27R signaling in myeloid cells, we generated Il27ra fl/fl mice and crossed them with LysM cre deleter to obtain LysM cre+ Il27ra f/f mice. Using MC-38 CRC cells portal vein injection model, we found that myeloid IL27Ra deletion leads to increased CRC-liver metastasis accompanied by increase in neutrophils, particularly Ly6G+Cxcr2-CD101- immature neutrophils, in circulation as well as tumors in LysM cre+ Il27ra f/f mice. Single-cell sequencing of tumor-infiltrating immune cells revealed that lack of IL27Ra in myeloid cells promoted neutrophil recruitment and degranulation as well as reactive oxygen species (ROS) and reactive nitrogen species (RNS) production but inhibited neutrophil maturation and production of pro-inflammatory chemokines and cytokines such as CXCL10, CSF1 and TNF. Furthermore, IL27Ra deficient neutrophils displayed heightened inflammatory response when stimulated with LPS in vitro. Collectively, our work reveals novel role of myeloid IL27Ra signaling that inhibits metastatic liver colonization by promoting neutrophil maturation, restricting neutrophil infiltration and degranulation. Citation Format: Jiani Zhu, Zhengzheng Shi, Ekaterina Koltsova. IL27R signaling regulates neutrophils maturation, activation and function in colorectal cancer-liver 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 C019.
Abstract C043: Alprazolam abrogates the secretion of proinflammatory cytokines in PDAC CAFs
Authors: Hunter D. Reavis, Arwen A. Tisdale, Kathryn E. Maraszek, Michael E. Feigin
Journal: Cancer Research (2024)

Abstract The present study sets out to determine how commonly prescribed triazolobenzodiazepines (triazoloBZDs) modulate the tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC), and how this can be leveraged therapeutically to improve patient outcomes. PDAC is one of the most lethal cancer subtypes with a 5-year survival rate of ∼13%. The poor prognosis of this disease is, in part, attributable to the dense, fibrotic tumor microenvironment (TME), and lack of durable responses to standard-of-care treatment options. A recent study from our lab reported that over 40% of PDAC patients at Roswell Park are prescribed benzodiazepines (BZDs) to manage anxiety, nausea, and other disease-related side effects. Importantly, survival outcomes in these patients varied in a compound-specific manner, as the usage of the n-unsubstituted BZD lorazepam was associated with poorer outcomes, while usage of the n-substituted triazoloBZD alprazolam was associated with improved progression-free survival. In vitro and in vivo data from the aforementioned study suggested that these findings may be a result of BZD-specific regulation of interleukin-6 (IL6), a proinflammatory cytokine with a known role in PDAC pathogenesis. More specifically, alprazolam-treated cancer-associated fibroblasts (CAFs) exhibited a potent reduction in IL6 transcription and secretion, while lorazepam treatment increased IL6 production. Based on these data, we hypothesized that triazoloBZDs may uniquely reduce intratumoral inflammation to alleviate immunosuppression in PDAC. We now find that triazoloBZDs such as alprazolam suppress the secretion of several proinflammatory cytokines (IL6, CCL2, CXCL12, IL8) by CAFs, the stromal components of the PDAC TME responsible for fibrosis and exclusion of immune infiltrates. Furthermore, we have observed that this phenotype is likely a result of triazoloBZD-mediated inhibition of the platelet- activating factor (PTAFR) signaling cascade. Investigations are currently underway to determine the impact of triazoloBZDs on regulating the immune landscape of the PDAC TME in vivo. Altogether, these findings provide a basis to inform clinical selection of BZDs for symptom management and present a novel therapeutic opportunity to repurpose FDA-approved compounds for treatment of PDAC. Citation Format: Hunter D. Reavis, Arwen A. Tisdale, Kathryn E. Maraszek, Michael E. Feigin. Alprazolam abrogates the secretion of proinflammatory cytokines in PDAC CAFs [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 C043.
Abstract PR011: Efferocytic macrophage promotes pancreatic cancer liver metastasis
Authors: Yuliana Astuti, Meirion Raymant, Valeria Quaranta, Kim Clarke, Maidinaimu Abudula, Olivia Smith, Gaia Bellomo, Vatshala Chandran-Gorner, Craig Nourse, Christopher Halloran, Paula Ghaneh, Daniel Palmer, Robert Jones, Fiona Campbell, Jeffrey Pollard, Jennifer Morton, Ainhoa Mielgo, Michael Schmid
Journal: Cancer Research (2024)

Abstract Pancreatic ductal adenocarcinoma (PDAC) presents a major therapeutic challenge due to its aggressive metastatic behavior. In the liver metastasis microenvironment of PDAC, macrophages are key drivers of tumor progression. Targeting these pro-tumorigenic macrophages requires a deep understanding of the various macrophage populations and the factors influencing their phenotypes. Our study has revealed a distinct subset of macrophages with a pro-tumorigenic phenotype that emerges early in PDAC liver metastasis. We found that the establishment of hepatic metastases triggers local tissue damage, which, through efferocytosis, reprograms macrophages into an immunosuppressive state, thereby facilitating metastasis. Inhibiting efferocytosis pharmacologically prevented the conversion of macrophages, enhanced CD8+ T cell responses, and reduced liver metastasis. These results highlight the role of macrophages in tissue repair processes that promote liver metastasis in PDAC and suggest potential therapeutic targets to hinder its progression. Citation Format: Yuliana Astuti, Meirion Raymant, Valeria Quaranta, Kim Clarke, Maidinaimu Abudula, Olivia Smith, Gaia Bellomo, Vatshala Chandran-Gorner, Craig Nourse, Christopher Halloran, Paula Ghaneh, Daniel Palmer, Robert Jones, Fiona Campbell, Jeffrey Pollard, Jennifer Morton, Ainhoa Mielgo, Michael Schmid. Efferocytic macrophage promotes pancreatic cancer liver 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 PR011.
Abstract C051: Epigenetic reprogramming of brain-infiltrating myeloid cells deters brain metastasis outgrowth
Authors: Shao-Ping Yang, Yimin Duan, Xiangliang Yuan, Lin Zhang, Wendao Liu, Jun Yao, Patrick Zhang, Jason T Huse, Zhongming Zhao, Dihua Yu
Journal: Cancer Research (2024)

Abstract The unique brain immune microenvironment (BrIME) co-evolves with brain metastasis (BrM) and is marked by immune suppression, posing a significant therapeutic challenge. BrIME is dominated by myeloid cells, with monocyte-derived macrophages (MDMs) comprising nearly half of the tumor-infiltrating leukocytes. Targeting MDMs remains challenging due to their inherent heterogeneity and high plasticity, which are regulated by epigenetic modifiers, including histone deacetylases (HDACs). Yet, the impact of HDAC inhibition in BrIME and its implications for BrM immunotherapy remains unclear. Here, we establish BrM syngenetic model by intracarotid artery (ICA) injection. Immune profiling by mass cytometry (CyTOF) analysis shows that selective class I HDAC inhibitor (HDACi) Entinostat (ENT) significantly enriches inflammatory MDMs in E0771 murine mammary tumor BrM model. Additionally, functional assay with bone marrow-derived macrophages (BMDMs) shows that ENT significantly enhances tumor cell phagocytosis and antigen presentation, increasing the proliferation of antigen-specific T cells in vitro. To test whether HDAC inhibition enhances antitumoral response in the BrIME, we designed a novel sequential treatment: with (1) ENT pre-conditioning the BrIME, (2) low- dose whole brain radiotherapy (LD-WBRT) to release tumor antigen followed by (3) anti-PD1 immune checkpoint therapy (ICT) to reinvigorate tumor-infiltrating. Our result shows that sequential triple treatment demonstrates significant BrM deterrence and induce a specific interferon-responsive MDM subset with robust type I interferon response in single-cell RNA sequencing, correlating with improved ICT clinical outcomes. Our data show that selective HDACi treatment reprograms the suppressive BrIME by steering the BrM-infiltrating MDMs toward immuno-stimulatory status. Sequential triple combinatorial therapy impedes BrM by activating innate and adaptive immunity simultaneously and is well tolerated in the animal model. Our findings highlight the potential of HDACi-mediated epigenetic reprogramming of the BrIME to enhance therapeutic efficacy in treating BrM. Citation Format: Shao-Ping Yang, Yimin Duan, Xiangliang Yuan, Lin Zhang, Wendao Liu, Jun Yao, Patrick Zhang, Jason T Huse, Zhongming Zhao, Dihua Yu. Epigenetic reprogramming of brain-infiltrating myeloid cells deters brain metastasis outgrowth [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 C051.
Abstract C033: Identifying and targeting prostate cancer therapy resistance mechanisms driven by the tumor microenvironment
Authors: Tony Lok Heng Chu, Armand Bankhead, Ilsa Coleman, Sander Frank, Peter S. Nelson, Tarana Arman
Journal: Cancer Research (2024)

Abstract Background: Prostate cancer is a prevalent malignancy in men, with treatment resistance posing a significant challenge to successful cure. Acquired Resistance to Therapy (ART) arises from two main components: (1) Tumor Microenvironment (TME) and (2) mutations or epigenetic changes at gene level within the tumor cells themselves. While most cancer therapies target the intrinsic biology of cancer cells, growing evidence indicates that these treatments can also harm the stromal cells within TME, potentially driving ART. The biology of ART may vary based on the types of treatments, cell types, and organ locations. Thus, this study aims to dissect ART components driven by TME-mediated cellular processes in a comprehensive manner. Hypothesis: We propose that cancer therapies induce stress responses in non-cancerous cells within the TME. These stress responses involve the secretion of cytokines, mediators, and growth factors, which we term Stress Response Secretory Programs (SRSPs). We further hypothesize that targeting SRSPs could overcome ART that helps to improve treatment specificity and efficacy. Materials and Methods: We employed comprehensive single-cell profiling of common metastatic sites included liver, prostate, lung, bone, lymph node and spleen in preclinical models to identify secreted proteins and dysregulated pathways caused by genotoxic therapies. In vitro, we evaluated treatment resistance in murine prostate epithelial cell lines (Myc-CAP) by exposing them to conditioned media (CM) from irradiated murine fibroblasts (F4M2), using cell growth assays. Results: Single-cell RNA sequencing of organ samples revealed significant expressions of SRSPs and increased inflammatory responses in liver and prostate fibroblasts as well as other stromal cells treated with carboplatin. In vitro, CM from irradiated F4M2 cells enhanced cell proliferation and survival of Myc-CAP cells in response to docetaxel treatment. Conclusion: Our findings highlight the crucial role of SRSPs in mediating ART through interactions within the TME, which alter tumor cell phenotypes. Targeting these SRSPs holds potential for overcoming treatment resistance and improving therapeutic outcomes, underscoring the need to consider TME complexity in cancer treatment strategies. Citation Format: Tony Lok Heng Chu, Armand Bankhead, Ilsa Coleman, Sander Frank, Peter S. Nelson, Tarana Arman. Identifying and targeting prostate cancer therapy resistance mechanisms driven by the 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 C033.
Abstract IA027: Age-related stromal changes drive breast cancer tumor progression
Authors: Sheila A. Stewart
Journal: Cancer Research (2024)

Abstract Age is the single largest risk factor for the development of cancer, but how age impacts the molecular mechanisms that drive cancer remain poorly understood. While it is clear that age-related accumulation of cell autonomous mutations contributes to tumorigenesis, the central role age-related changes in the tumor microenvironment play in the transformation process is becoming more fully appreciated. Underscoring the importance of an aged microenvironment in cancer development are findings that senescent fibroblasts, which accumulate with age, directly stimulate preneoplastic and neoplastic cell growth and tumor progression. Investigations into how senescent fibroblasts promote tumorigenesis revealed that they express a plethora of growth factors, extracellular matrix remodeling enzymes, chemokines, and cytokines collectively referred to as the senescence associated secretory phenotype (SASP). Chemotherapy induces similar changes that can negatively impact a patient’s quality of life. We will discuss how these changes impact tumor progression and therapy-induced bone loss. Citation Format: Sheila A. Stewart. Age-related stromal changes drive breast cancer tumor 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 IA027.