Publications by authors named "Rosa E Menjivar"

Pancreatic ductal adenocarcinoma (PDAC) is a drug resistant and lethal cancer. Identification of the genes that consistently show altered expression across patients' cohorts can expose effective therapeutic targets and strategies. To identify such genes, we separately analyzed five human PDAC microarray datasets.

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Pancreatic cancer is characterized by an extensive fibroinflammatory microenvironment. During carcinogenesis, normal stromal cells are converted to cytokine-high cancer-associated fibroblasts (CAF). The mechanisms underlying this conversion, including the regulation and function of fibroblast-derived cytokines, are poorly understood.

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Article Synopsis
  • Tumor progression leads to fibrosis, which involves excessive buildup of extracellular matrix and reduces immune cell infiltration, particularly affecting CD8 T cells.
  • Tumor-associated macrophages (TAMs) adapt to the stiff fibrotic environment by promoting collagen production through signaling from transforming growth factor-β.
  • This collagen production by TAMs creates a challenging metabolic environment that limits the effectiveness of CD8 T cells, hindering their ability to mount strong antitumor responses in breast cancer patients.
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Pancreatic ductal adenocarcinoma (PDA) continues to have a dismal prognosis. The poor survival of patients with PDA has been attributed to a high rate of early metastasis and low efficacy of current therapies, which partly result from its complex immunosuppressive tumor microenvironment. Previous studies from our group and others have shown that tumor-associated macrophages (TAM) are instrumental in maintaining immunosuppression in PDA.

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Nutrient stress in the tumor microenvironment requires cancer cells to adopt adaptive metabolic programs for survival and proliferation. Therefore, knowledge of microenvironmental nutrient levels and how cancer cells cope with such nutrition is critical to understand the metabolism underpinning cancer cell biology. Previously, we performed quantitative metabolomics of the interstitial fluid (the local perfusate) of murine pancreatic ductal adenocarcinoma (PDAC) tumors to comprehensively characterize nutrient availability in the microenvironment of these tumors.

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Pancreatic ductal adenocarcinoma (PDA) is a lethal disease notoriously resistant to therapy. This is mediated in part by a complex tumour microenvironment, low vascularity, and metabolic aberrations. Although altered metabolism drives tumour progression, the spectrum of metabolites used as nutrients by PDA remains largely unknown.

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An extensive fibroinflammatory stroma rich in macrophages is a hallmark of pancreatic cancer. In this disease, it is well appreciated that macrophages are immunosuppressive and contribute to the poor response to immunotherapy; however, the mechanisms of immune suppression are complex and not fully understood. Immunosuppressive macrophages are classically defined by the expression of the enzyme Arginase 1 (ARG1), which we demonstrated is potently expressed in pancreatic tumor-associated macrophages from both human patients and mouse models.

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Pancreatic ductal adenocarcinoma (PDA) continues to have a dismal prognosis. The poor survival of patients with PDA has been attributed to a high rate of early metastasis and low efficacy of current therapies, which partly result from its complex immunosuppressive tumor microenvironment. Previous studies from our group and others have shown that tumor-associated macrophages (TAMs) are instrumental in maintaining immunosuppression in PDA.

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Article Synopsis
  • Pancreatic ductal adenocarcinoma (PDA) is linked to WNT signaling activation, which influences the tumor microenvironment.
  • Single-cell RNA sequencing of human pancreatic cancer revealed that CD4+ T cells in the tumors express TCF7, affecting immune responses.
  • Inhibiting WNT signaling and using a PD-L1 blocker in combination showed promising results in reducing tumor growth, suggesting a potential new treatment approach for PDA.
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Proper Hedgehog (HH) signaling is essential for embryonic development, while aberrant HH signaling drives pediatric and adult cancers. HH signaling is frequently dysregulated in pancreatic cancer, yet its role remains controversial, with both tumor-promoting and tumor-restraining functions reported. Notably, the GLI family of HH transcription factors (GLI1, GLI2, GLI3), remain largely unexplored in pancreatic cancer.

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Article Synopsis
  • Oncogenic KRAS is a key mutation in pancreatic cancer that not only affects tumor cells but also influences the surrounding tumor microenvironment, which remains poorly understood.
  • In this study, researchers used genetically engineered mice and advanced techniques like mass cytometry and single-cell RNA sequencing to investigate how oncogenic KRAS impacts pancreatic fibroblasts.
  • Findings reveal that KRAS signaling reprograms fibroblasts to become active players in inflammation, enhancing protumorigenic macrophage activity and hindering tissue repair, opening doors for potential therapeutic strategies targeting these stromal pathways.
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Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with few effective therapeutic options. PDAC is characterized by an extensive fibroinflammatory stroma that includes abundant infiltrating immune cells. Tumor-associated macrophages (TAM) are prevalent within the stroma and are key drivers of immunosuppression.

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Regulatory T cells (Treg) are abundant in human and mouse pancreatic cancer. To understand the contribution to the immunosuppressive microenvironment, we depleted Tregs in a mouse model of pancreatic cancer. Contrary to our expectations, Treg depletion failed to relieve immunosuppression and led to accelerated tumor progression.

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Background: Neurofibromatosis 1 and 2, although involving two different tumour suppressor genes (neurofibromin and merlin, respectively), are both cancer predisposition syndromes that disproportionately affect cells of neural crest origin. New therapeutic approaches for both NF1 and NF2 are badly needed. In promising previous work we demonstrated that two non-steroidal analogues of 2-methoxy-oestradiol (2ME2), STX3451(2-(3-bromo-4,5-dimethoxybenzyl)-7-methoxy-6-sulfamoyloxy-1,2,3,4-tetrahydroisoquinoline), and STX2895 (7-Ethyl-6-sulfamoyloxy-2-(3,4,5-trimethoxybenzyl)-1,2,3,4-tetrahydroisoquinoline) reduced tumour cell growth and induced apoptosis in malignant and benign human Neurofibromatosis 1 (NF1) tumour cells.

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