Publications by authors named "Gravekamp C"

Among bacteria used as anticancer vaccines, attenuated (Lm) stands out, because it spreads from one infected cancer cell to the next, induces a strong adaptive immune response, and is suitable for repeated injection cycles. Here, we use click chemistry to functionalize the Lm cell wall and turn the bacterium into an "intelligent carrier" of the chemotherapeutic drug doxorubicin. Doxorubicin-loaded Lm retains most of its biological properties and, compared to the control fluorophore-functionalized bacteria, shows enhanced cytotoxicity against melanoma cells both in vitro and in a xenograft model in zebrafish.

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Article Synopsis
  • Early-stage breast cancer usually has a good outlook, but if it spreads, especially to the lungs, the prognosis declines; tumor-infiltrating T cells can help control tumors, particularly those with a memory function.
  • A study was conducted using a vaccine to create specific T cells in the lungs of mice to prevent and treat lung metastases in breast cancer.
  • The vaccine was effective in generating these T cells, reducing lung metastasis growth, and improving survival rates; when used with radiotherapy, it further enhanced outcomes for tumor-bearing mice.
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Ovarian cancer is known for its poor neoantigen expression and strong immunosuppression. Here, we utilized an attenuated non-pathogenic bacterium Listeria monocytogenes to deliver a highly immunogenic Tetanus Toxoid protein (Listeria-TT), as a neoantigen surrogate, into tumor cells through infection in a metastatic mouse ovarian cancer model (Id8p53-/-Luc). Gemcitabine (GEM) was added to reduce immune suppression.

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The physiology and pathophysiology of the pancreas are complex. Diseases of the pancreas, such as pancreatitis and pancreatic adenocarcinoma (PDAC) have high morbidity and mortality. Intravital imaging (IVI) is a powerful technique enabling the high-resolution imaging of tissues in both healthy and diseased states, allowing for real-time observation of cell dynamics.

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Pancreatitis and pancreatic ductal adenocarcinoma (PDAC) are grave illnesses with high levels of morbidity and mortality. Intravital imaging (IVI) is a powerful technique for visualizing physiological processes in both health and disease. However, the application of IVI to the murine pancreas presents significant challenges, as it is a deep, compliant, visceral organ that is difficult to access, easily damaged and susceptible to motion artefacts.

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Article Synopsis
  • Pancreatic ductal adenocarcinoma (PDAC) is difficult to treat due to its ability to evade immune responses, but a new microbiome-based therapy shows promise by introducing a tetanus toxoid protein into tumor cells, reactivating existing T cell responses.
  • In mouse models, this treatment led to the accumulation of the tetanus protein in tumors, recruitment of CD4 T cells, and the production of immune molecules that help kill tumor cells, especially when combined with low doses of gemcitabine (GEM).
  • The combination treatment significantly reduced tumor size (by 80%) and metastases (by 87%), while increasing survival rates in treated mice, suggesting this approach could be a viable alternative for
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Background: Treatments for pancreatic ductal adenocarcinoma are poorly effective, at least partly due to the tumor's immune-suppressive stromal compartment. New evidence of positive effects on immune responses in the tumor microenvironment (TME), compelled us to test the combination of gemcitabine (GEM), a standard chemotherapeutic for pancreatic cancer, with nicotinamide (NAM), the amide form of niacin (vitamin B), in mice with pancreatic cancer.

Methods: Various mouse tumor models of pancreatic cancer, that is, orthotopic Panc-02 and KPC (Kras, p53, Pdx1-Cre) grafts, were treated alternately with NAM and GEM for 2 weeks, and the effects on efficacy, survival, stromal architecture and tumor-infiltrating immune cells was examined by immunohistochemistry (IHC), flow cytometry, Enzyme-linked immunospot (ELISPOT), T cell depletions in vivo, Nanostring analysis and RNAscope.

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Attenuated Listeria monocytogenes (Lm-LLO) represents a valuable anticancer vaccine and drug delivery platform. Here we show that in vitro Lm-LLO causes ROS production and, in turn, apoptotic killing of a wide variety of melanoma cells, irrespectively of their stage, mutational status, sensitivity to BRAF inhibitors or degree of stemness. We also show that, when administered in the therapeutic setting to Braf/Pten genetically engineered mice, Lm-LLO causes a strong decrease in the size and volume of primary melanoma tumors, as well as a reduction of the metastatic burden.

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Recent advances in targeted therapy and immunotherapy have once again raised the hope that a cure might be within reach for many cancer types. Yet, most late-stage cancers are either insensitive to the therapies to begin with or develop resistance later. Therapy with live tumour-targeting bacteria provides a unique option to meet these challenges.

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In this White Paper, we discuss the current state of microbial cancer therapy. This paper resulted from a meeting ('Microbial Based Cancer Therapy') at the US National Cancer Institute in the summer of 2017. Here, we define 'Microbial Therapy' to include both oncolytic viral therapy and bacterial anticancer therapy.

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Cancer immunotherapy is one of the most promising and benign therapies against metastatic cancer. However, most cancer patients are old and elderly react less efficient to cancer vaccines than young adults, due to T cell unresponsiveness. Here we present data of cancer vaccination in young and old mice with metastatic breast cancer (4T1 model).

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There is a need for novel effective and safe therapies for metastatic breast cancer based on targeting tumor-specific molecular markers of cancer. Human aspartyl (asparaginyl) β-hydroxylase (HAAH) is a highly conserved enzyme that hydroxylates epidermal growth factor-like domains in transformation-associated proteins and is overexpressed in a variety of cancers, including breast cancer. A fully human monoclonal antibody (mAb) PAN-622 has been developed to HAAH.

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Our laboratory has developed a novel delivery platform using an attenuated non-toxic and non-pathogenic bacterium Listeria monocytogenes that infects tumor cells and selectively survives and multiplies in metastases and primary tumors with help of myeloid-derived suppressor cells (MDSC) and immune suppression in the tumor microenvironment (TME). 32P was efficiently incorporated into the Listeria bacteria by starvation of the bacteria in saline, and then cultured in phosphorus-free medium complemented with 32P as a nutrient. Listeria-32P kills tumor cells through both 32P-induced ionizing radiation and Listeria-induced reactive oxygen species (ROS).

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Aging is the major risk factor for both the development of chronic diseases and loss of functional capacity. Geroscience provides links among the biology of aging, the biology of disease, and the physiology of frailty, three fields where enormous progress has been made in the last few decades. While, previously, the focus was on the role of aging in susceptibility to disease and disability, the other side of this relationship, which is the contribution of disease to aging, has been less explored at the molecular/cellular level.

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Interleukin-6, a cytokine produced particularly by triple-negative breast cancers, strongly inhibits T cell responses in the tumor microenvironment. Here we tested cryoablation combined with Meriva (a lecithin delivery system of curcumin with improved bioavailability) in mice with metastatic breast cancer (4T1). Cryoablation involves killing of tumor cells through freezing and thawing, resulting in recruitment of tumor-specific T cells, while curcumin stimulates T cells through the reduction of IL-6 in the TME.

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Background: Chelidonium majus L. (Papaveraceae) (greater celandine) is a medicinal herb that is widely spread in Europe. Antitumoural activity has been reported for C.

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Recently, we demonstrated that stimulator of interferon genes (STING) ligand cyclic di-guanylate (c-di-GMP) is an excellent adjuvant in cancer vaccination but also induces immunogenic tumor cell death. Combination of both pathways resulted in a nearly complete elimination of the metastases in a breast cancer model. This study is discussed below.

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Pancreatic malignancies, the fourth leading cause of cancer deaths, have an aggressive behavior with poor prognosis, resulting in a 5-year survival rate of only 4%. It is typically a silent malignancy until patients develop metastatic disease. Targeted radionuclide therapies of cancer such as radiolabeled peptides, which bind to the receptors overexpressed by cancer cells and radiolabeled antibodies to tumor-specific antigens provide a viable alternative to chemotherapy and external beam radiation of metastatic cancers.

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Sanguinarine has a history of use in both folk medicine and early dermatology for the treatment of cutaneous neoplasms. Applied indiscriminately, bloodroot is an escharotic agent with potential to cause extensive tissue necrosis. However, when used in a controlled fashion, sanguinarine imparts selective cytotoxic/anti-proliferative activity through multiple mechanisms against human/ murine melanoma.

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Background: Immune suppression in the tumour microenvironment remains a major limitation to successful immunotherapy of cancer. In the current study, we analysed whether the natural killer T cell-activating glycolipid α-galactosylceramide could overcome immune suppression and improve vaccination against metastatic breast cancer.

Methods: Mice with metastatic breast cancer (4T1 model) were therapeutically treated with a Listeria monocytogenes-based vaccine expressing tumour-associated antigen Mage-b followed by α-galactosylceramide as separate agents, or as a complex of α-galactosylceramide stably incorporated into Listeria-Mage-b.

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Chaperone-mediated autophagy (CMA) targets soluble proteins for lysosomal degradation. Here we found that CMA was activated in T cells in response to engagement of the T cell antigen receptor (TCR), which induced expression of the CMA-related lysosomal receptor LAMP-2A. In activated T cells, CMA targeted the ubiquitin ligase Itch and the calcineurin inhibitor RCAN1 for degradation to maintain activation-induced responses.

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Cancer vaccination may be our best and most benign option for preventing or treating metastatic cancer. However, breakthroughs are hampered by immune suppression in the tumor microenvironment. In this study, we analyzed whether cyclic diguanylate (c-di-GMP), a ligand for stimulator of interferon genes (STING), could overcome immune suppression and improve vaccination against metastatic breast cancer.

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Age-related defects of the immune system are responsible for T cell unresponsiveness to cancer vaccination at older age. Major immune defects at older age are lack of naive T cells, impaired activation pathways of T cells and antigen-presenting cells (APCs), and age-related changes in the tumor microenvironment (TME). This raises the question whether cancer vaccination is feasible at older age.

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While conventional anticancer therapies, including surgical resection, radiotherapy, and/or chemotherapy, are relatively efficient at eliminating primary tumors, these treatment modalities are largely ineffective against metastases. At least in part, this reflects the rather inefficient delivery of conventional anticancer agents to metastatic lesions. We have recently demonstrated that myeloid-derived suppressor cells (MDSCs) can be used as cellular missiles to selectively deliver a radioisotope-coupled attenuated variant of to both primary and metastatic neoplastic lesions in mice with pancreatic cancer.

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