New powerful anti-inflammatory agents (prodrugs) were developed which act by esterase-triggered, ... more New powerful anti-inflammatory agents (prodrugs) were developed which act by esterase-triggered, simultaneous release of itaconate and the gasotransmitter carbon monoxide.
Hexadecylphosphocholine (HePC), a topically effective compound, exerts a strong antiproliferative... more Hexadecylphosphocholine (HePC), a topically effective compound, exerts a strong antiproliferative effect on neoplastic cells. In the present study we investigated (1) the antiproliferative effect of HePC on benign mesenchymal cells in vitro, using as examples normal and keloid fibroblasts, and (2) the influence of HePC on various functional properties of these cells, including phosphatidylcholine biosynthesis, their capacity to reorganize a three-dimensional collagen-I matrix, and their expression and synthesis of fibronectin and subunits of the beta 1 integrin family. Fibroblasts derived from keloids (kelfib) and from normal skin (nfib) were cultured in serum-containing medium and treated in the third passage with 50 mumol/l HePC. Proliferative activity was significantly (P < 0.05) more strongly inhibited in kelfib than in nfib under HePC treatment, whereas their phosphatidylcholine synthesis was inhibited to a similar extent. However, the ability of fibroblasts to contract a three-dimensional collagen-I lattice was significantly (P < 0.05) enhanced only in kelfib treated with HePC. These functional differences following treatment with HePC were paralleled by an upregulation of the alpha 2- and beta 1-integrin chains, and a downregulation of fibronectin synthesis and the alpha 5-subunit. Our results indicate a differential modulation of kelfib metabolism by HePC, suggesting a possible new therapeutic approach for keloid and hypertrophic scars in vivo.
Immune checkpoint blockade (ICB)-based or natural cancer immune responses largely eliminate tumou... more Immune checkpoint blockade (ICB)-based or natural cancer immune responses largely eliminate tumours. Yet, they require additional mechanisms to arrest those cancer cells that are not rejected. Cytokine-induced senescence (CIS) can stably arrest cancer cells, suggesting that interferon-dependent induction of senescence-inducing cell cycle regulators is needed to control those cancer cells that escape from killing. Here we report in two different cancers sensitive to T cell-mediated rejection, that deletion of the senescence-inducing cell cycle regulators p16Ink4a/p19Arf (Cdkn2a) or p21Cip1 (Cdkn1a) in the tumour cells abrogates both the natural and the ICB-induced cancer immune control. Also in humans, melanoma metastases that progressed rapidly during ICB have losses of senescence-inducing genes and amplifications of senescence inhibitors. Metastatic cells also resist CIS. Such genetic and functional alterations are infrequent in metastatic melanomas regressing during ICB. Thus, act...
Costunolide, a natural sesquiterpene lactone, has multiple pharmacological activities such as neu... more Costunolide, a natural sesquiterpene lactone, has multiple pharmacological activities such as neuroprotection or induction of apoptosis and eryptosis. However, the effects of costunolide on pro-survival factors and enzymes in human erythrocytes, e.g. glutathione and glucose-6-phosphate dehydrogenase (G6PDH) respectively, have not been studied yet. Our aim was to determine the mechanisms underlying costunolide-induced eryptosis and to reverse this process. Phosphatidylserine exposure was estimated from annexin-V-binding, cell volume from forward scatter in flow cytometry, and intracellular glutathione [GSH]ifrom high performance liquid chromatography. The oxidized status of intracellular glutathione and enzyme activities were measured by spectrophotometry. Treatment of erythrocytes with costunolide dose-dependently enhanced the percentage of annexin-V-binding cells, decreased the cell volume, depleted [GSH]iand completely inhibited G6PDH activity. The effects of costunolide on annexi...
Immune checkpoint blockade (ICB) therapy is a central pillar of melanoma treatment leading to dur... more Immune checkpoint blockade (ICB) therapy is a central pillar of melanoma treatment leading to durable response rates. Important mechanisms of action of ICB therapy include disinhibition of CD4+ and CD8+ T cells. Stimulated CD4+ T helper 1 cells secrete the effector cytokines interferon-gamma (IFN-γ) and tumor necrosis factor alpha (TNF), which induce senescence in tumor cells. Besides being growth-arrested, senescent cells are metabolically active and secrete a large spectrum of factors, which are summarized as senescence-associated secretory phenotype (SASP). This secretome affects the tumor growth. Here, we compared the SASP of cytokine-induced senescent (CIS) cells with the SASP of therapy-induced senescent (TIS) cells. Therefore, we established in vitro models for CIS and TIS in melanoma. The human melanoma cell lines SK-MEL-28 and WM115 were treated with the cytokines IFN-γ and TNF as CIS, the chemotherapeutic agent doxorubicin, and the cell cycle inhibitor palbociclib as TIS. ...
In contrast to surgical excision, chemotherapy or radiation therapy, immune checkpoint blockade t... more In contrast to surgical excision, chemotherapy or radiation therapy, immune checkpoint blockade therapies primarily influence cells in the tumor microenvironment, especially the tumor-associated lymphocytes and antigen-presenting cells. Besides complete remission of tumor lesions, in some patients, early tumor regression is followed by a consolidation phase where residing tumors remain dormant. Whereas the cytotoxic mechanisms of the regression phase (i.e., apoptosis, necrosis, necroptosis, and immune cell-mediated cell death) have been extensively described, the mechanisms underlying the dormant state are still a matter of debate. Here, we propose immune-mediated induction of senescence in cancers as one important player. Senescence can be achieved by tumor-associated antigen-specific T helper 1 cells, cytokines or antibodies targeting immune checkpoints. This concept differs from cytotoxic treatment, which often targets the genetic makeup of cancer cells. The immune system’s abili...
Human erythrocytes are organelle-free cells packaged with iron-containing hemoglobin, specializin... more Human erythrocytes are organelle-free cells packaged with iron-containing hemoglobin, specializing in the transport of oxygen. With a total number of approximately 25 trillion cells per individual, the erythrocyte is the most abundant cell type not only in blood but in the whole organism. Despite their low complexity and their inability to transcriptionally upregulate antioxidant defense mechanisms, they display a relatively long life time, of 120 days. This ensures the maintenance of tissue homeostasis where the clearance of old or damaged erythrocytes is kept in balance with erythropoiesis. Whereas the regulatory mechanisms of erythropoiesis have been elucidated over decades of intensive research, the understanding of the mechanisms of erythrocyte clearance still requires some refinement. Here, we present the main pathways leading to eryptosis, the programmed death of erythrocytes, with special emphasis on Ca2+ influx, the generation of ceramide, oxidative stress, kinase activatio...
Immune responses may control tumorigenesis and metastasis. Most antitumor interventions have been... more Immune responses may control tumorigenesis and metastasis. Most antitumor interventions have been designed to boost the immune system in its fight to destroy cancerous cells. In the last decades, the biological mechanisms of tumor immune control have been mainly studied in the context of cancer cell destruction. Thus, tumor dormancy is still considered as an equilibrium between cell proliferation and cell death, i.e., cancer cell apoptosis, cancer cell lysis, or pyroptosis. Here, we propose cellular senescence induced by recombinant cytokines, e.g., interferon-α (IFN-α) and tumor necrosis factor (TNF), as a novel therapeutic regimen, especially for the treatment of intraperitoneal tumors. Immunity-induced senescence triggers a stable cell-cycle arrest of cancer cells and engages the immune system to construct a defensive, isolating barrier around the tumors. These newly developed therapies aim at controlling the tumor burden by transforming the deadly disease into a chronic one.
The mechanism of the inhibition of phosphatidylcholine biosynthesis by the phospholipid analogue,... more The mechanism of the inhibition of phosphatidylcholine biosynthesis by the phospholipid analogue, hexadecylphosphocholine, was investigated in Madin-Darby canine kidney cells. In the presence of 50 mumol/liter hexadecylphosphocholine, there was a translocation of CTP:choline-phosphate cytidylyltransferase (EC 22.7.7.15) activity from the membranes to the cytosol of the cells. Since we recently demonstrated that hexadecylphosphocholine also inhibits protein kinase C in vitro, [methyl-3H]choline labeling experiments were repeated with phorbol ester-desensitized cells. In these cells the same inhibitory effect of hexadecylphosphocholine was measured. As a consequence of inhibition, the [methyl-3H]choline incorporation into the phosphocholine pool was increased time-dependently. In addition, there was no evidence for a difference between the choline uptake of control and hexadecylphosphocholine-treated cells. Likewise, the amount of diacylglycerol, a known activator of the translocation process, was not reduced. Finally, we showed that the inhibitory effect of hexadecylphosphocholine on CTP:choline-phosphate cytidylyltransferase translocation cannot be explained by the detergent properties of this phospholipid analogue. Therefore, we suggest a direct inhibitory effect of hexadecylphosphocholine on the translocation of CTP:choline-phosphate cytidylyltransferase.
Background/Aims: Cellular senescence, or permanent growth arrest, is known as an effective tumor ... more Background/Aims: Cellular senescence, or permanent growth arrest, is known as an effective tumor suppressor mechanism that can be induced by different stressors, such as oncogenes, chemotherapeutics or cytokine cocktails. Previous studies demonstrated that the growth-repressing state of oncogene-induced senescent cells depends on argonaute protein 2 (Ago2)-mediated transcriptional gene silencing and Ago2/Rb corepression of E2F-dependent cell cycle genes. Cytokine-induced senescence (CIS) likewise depends on activation of the p16Ink4a/Rb pathway, and consecutive inactivation of the E2F family of transcription factors. In the present study, we therefore analyzed the role of Ago2 in CIS. Methods: Human cancer cell lines were treated with interferon-gamma (IFN-γ) and tumor necrosis factor (TNF) to induce senescence. Senescence was determined by growth assays and measurement of senescence-associated β-galactosidase (SA-β-gal) activity, Ago2 translocation by Ago2/ Ki67 immunofluorescence ...
The Journal of allergy and clinical immunology, Jan 27, 2018
Immune checkpoints are accessory molecules that either promote or inhibit T-cell activation. Two ... more Immune checkpoints are accessory molecules that either promote or inhibit T-cell activation. Two inhibitory molecules, cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1), got high attention, as inhibition of CTLA-4 or PD-1 signaling provides the first immune therapy that significantly improves the survival of patients with metastatic solid cancers. Inhibition of CTLA-4 or PD-1 was first studied in and approved for patients with metastatic melanoma. Blocking immune checkpoints is also efficient in non-small-cell lung cancer, renal cell cancers, hypermutated gastrointestinal cancers, and others. Immune responses, whether directed against infections or against tumors, are divided into 2 phases: an initiation phase and an activation phase, where the immune system recognizes a danger signal and becomes activated by innate signals to fight the danger. This reaction is fundamental for the control of infections and cancer, but needs to be turned off once th...
New powerful anti-inflammatory agents (prodrugs) were developed which act by esterase-triggered, ... more New powerful anti-inflammatory agents (prodrugs) were developed which act by esterase-triggered, simultaneous release of itaconate and the gasotransmitter carbon monoxide.
Hexadecylphosphocholine (HePC), a topically effective compound, exerts a strong antiproliferative... more Hexadecylphosphocholine (HePC), a topically effective compound, exerts a strong antiproliferative effect on neoplastic cells. In the present study we investigated (1) the antiproliferative effect of HePC on benign mesenchymal cells in vitro, using as examples normal and keloid fibroblasts, and (2) the influence of HePC on various functional properties of these cells, including phosphatidylcholine biosynthesis, their capacity to reorganize a three-dimensional collagen-I matrix, and their expression and synthesis of fibronectin and subunits of the beta 1 integrin family. Fibroblasts derived from keloids (kelfib) and from normal skin (nfib) were cultured in serum-containing medium and treated in the third passage with 50 mumol/l HePC. Proliferative activity was significantly (P < 0.05) more strongly inhibited in kelfib than in nfib under HePC treatment, whereas their phosphatidylcholine synthesis was inhibited to a similar extent. However, the ability of fibroblasts to contract a three-dimensional collagen-I lattice was significantly (P < 0.05) enhanced only in kelfib treated with HePC. These functional differences following treatment with HePC were paralleled by an upregulation of the alpha 2- and beta 1-integrin chains, and a downregulation of fibronectin synthesis and the alpha 5-subunit. Our results indicate a differential modulation of kelfib metabolism by HePC, suggesting a possible new therapeutic approach for keloid and hypertrophic scars in vivo.
Immune checkpoint blockade (ICB)-based or natural cancer immune responses largely eliminate tumou... more Immune checkpoint blockade (ICB)-based or natural cancer immune responses largely eliminate tumours. Yet, they require additional mechanisms to arrest those cancer cells that are not rejected. Cytokine-induced senescence (CIS) can stably arrest cancer cells, suggesting that interferon-dependent induction of senescence-inducing cell cycle regulators is needed to control those cancer cells that escape from killing. Here we report in two different cancers sensitive to T cell-mediated rejection, that deletion of the senescence-inducing cell cycle regulators p16Ink4a/p19Arf (Cdkn2a) or p21Cip1 (Cdkn1a) in the tumour cells abrogates both the natural and the ICB-induced cancer immune control. Also in humans, melanoma metastases that progressed rapidly during ICB have losses of senescence-inducing genes and amplifications of senescence inhibitors. Metastatic cells also resist CIS. Such genetic and functional alterations are infrequent in metastatic melanomas regressing during ICB. Thus, act...
Costunolide, a natural sesquiterpene lactone, has multiple pharmacological activities such as neu... more Costunolide, a natural sesquiterpene lactone, has multiple pharmacological activities such as neuroprotection or induction of apoptosis and eryptosis. However, the effects of costunolide on pro-survival factors and enzymes in human erythrocytes, e.g. glutathione and glucose-6-phosphate dehydrogenase (G6PDH) respectively, have not been studied yet. Our aim was to determine the mechanisms underlying costunolide-induced eryptosis and to reverse this process. Phosphatidylserine exposure was estimated from annexin-V-binding, cell volume from forward scatter in flow cytometry, and intracellular glutathione [GSH]ifrom high performance liquid chromatography. The oxidized status of intracellular glutathione and enzyme activities were measured by spectrophotometry. Treatment of erythrocytes with costunolide dose-dependently enhanced the percentage of annexin-V-binding cells, decreased the cell volume, depleted [GSH]iand completely inhibited G6PDH activity. The effects of costunolide on annexi...
Immune checkpoint blockade (ICB) therapy is a central pillar of melanoma treatment leading to dur... more Immune checkpoint blockade (ICB) therapy is a central pillar of melanoma treatment leading to durable response rates. Important mechanisms of action of ICB therapy include disinhibition of CD4+ and CD8+ T cells. Stimulated CD4+ T helper 1 cells secrete the effector cytokines interferon-gamma (IFN-γ) and tumor necrosis factor alpha (TNF), which induce senescence in tumor cells. Besides being growth-arrested, senescent cells are metabolically active and secrete a large spectrum of factors, which are summarized as senescence-associated secretory phenotype (SASP). This secretome affects the tumor growth. Here, we compared the SASP of cytokine-induced senescent (CIS) cells with the SASP of therapy-induced senescent (TIS) cells. Therefore, we established in vitro models for CIS and TIS in melanoma. The human melanoma cell lines SK-MEL-28 and WM115 were treated with the cytokines IFN-γ and TNF as CIS, the chemotherapeutic agent doxorubicin, and the cell cycle inhibitor palbociclib as TIS. ...
In contrast to surgical excision, chemotherapy or radiation therapy, immune checkpoint blockade t... more In contrast to surgical excision, chemotherapy or radiation therapy, immune checkpoint blockade therapies primarily influence cells in the tumor microenvironment, especially the tumor-associated lymphocytes and antigen-presenting cells. Besides complete remission of tumor lesions, in some patients, early tumor regression is followed by a consolidation phase where residing tumors remain dormant. Whereas the cytotoxic mechanisms of the regression phase (i.e., apoptosis, necrosis, necroptosis, and immune cell-mediated cell death) have been extensively described, the mechanisms underlying the dormant state are still a matter of debate. Here, we propose immune-mediated induction of senescence in cancers as one important player. Senescence can be achieved by tumor-associated antigen-specific T helper 1 cells, cytokines or antibodies targeting immune checkpoints. This concept differs from cytotoxic treatment, which often targets the genetic makeup of cancer cells. The immune system’s abili...
Human erythrocytes are organelle-free cells packaged with iron-containing hemoglobin, specializin... more Human erythrocytes are organelle-free cells packaged with iron-containing hemoglobin, specializing in the transport of oxygen. With a total number of approximately 25 trillion cells per individual, the erythrocyte is the most abundant cell type not only in blood but in the whole organism. Despite their low complexity and their inability to transcriptionally upregulate antioxidant defense mechanisms, they display a relatively long life time, of 120 days. This ensures the maintenance of tissue homeostasis where the clearance of old or damaged erythrocytes is kept in balance with erythropoiesis. Whereas the regulatory mechanisms of erythropoiesis have been elucidated over decades of intensive research, the understanding of the mechanisms of erythrocyte clearance still requires some refinement. Here, we present the main pathways leading to eryptosis, the programmed death of erythrocytes, with special emphasis on Ca2+ influx, the generation of ceramide, oxidative stress, kinase activatio...
Immune responses may control tumorigenesis and metastasis. Most antitumor interventions have been... more Immune responses may control tumorigenesis and metastasis. Most antitumor interventions have been designed to boost the immune system in its fight to destroy cancerous cells. In the last decades, the biological mechanisms of tumor immune control have been mainly studied in the context of cancer cell destruction. Thus, tumor dormancy is still considered as an equilibrium between cell proliferation and cell death, i.e., cancer cell apoptosis, cancer cell lysis, or pyroptosis. Here, we propose cellular senescence induced by recombinant cytokines, e.g., interferon-α (IFN-α) and tumor necrosis factor (TNF), as a novel therapeutic regimen, especially for the treatment of intraperitoneal tumors. Immunity-induced senescence triggers a stable cell-cycle arrest of cancer cells and engages the immune system to construct a defensive, isolating barrier around the tumors. These newly developed therapies aim at controlling the tumor burden by transforming the deadly disease into a chronic one.
The mechanism of the inhibition of phosphatidylcholine biosynthesis by the phospholipid analogue,... more The mechanism of the inhibition of phosphatidylcholine biosynthesis by the phospholipid analogue, hexadecylphosphocholine, was investigated in Madin-Darby canine kidney cells. In the presence of 50 mumol/liter hexadecylphosphocholine, there was a translocation of CTP:choline-phosphate cytidylyltransferase (EC 22.7.7.15) activity from the membranes to the cytosol of the cells. Since we recently demonstrated that hexadecylphosphocholine also inhibits protein kinase C in vitro, [methyl-3H]choline labeling experiments were repeated with phorbol ester-desensitized cells. In these cells the same inhibitory effect of hexadecylphosphocholine was measured. As a consequence of inhibition, the [methyl-3H]choline incorporation into the phosphocholine pool was increased time-dependently. In addition, there was no evidence for a difference between the choline uptake of control and hexadecylphosphocholine-treated cells. Likewise, the amount of diacylglycerol, a known activator of the translocation process, was not reduced. Finally, we showed that the inhibitory effect of hexadecylphosphocholine on CTP:choline-phosphate cytidylyltransferase translocation cannot be explained by the detergent properties of this phospholipid analogue. Therefore, we suggest a direct inhibitory effect of hexadecylphosphocholine on the translocation of CTP:choline-phosphate cytidylyltransferase.
Background/Aims: Cellular senescence, or permanent growth arrest, is known as an effective tumor ... more Background/Aims: Cellular senescence, or permanent growth arrest, is known as an effective tumor suppressor mechanism that can be induced by different stressors, such as oncogenes, chemotherapeutics or cytokine cocktails. Previous studies demonstrated that the growth-repressing state of oncogene-induced senescent cells depends on argonaute protein 2 (Ago2)-mediated transcriptional gene silencing and Ago2/Rb corepression of E2F-dependent cell cycle genes. Cytokine-induced senescence (CIS) likewise depends on activation of the p16Ink4a/Rb pathway, and consecutive inactivation of the E2F family of transcription factors. In the present study, we therefore analyzed the role of Ago2 in CIS. Methods: Human cancer cell lines were treated with interferon-gamma (IFN-γ) and tumor necrosis factor (TNF) to induce senescence. Senescence was determined by growth assays and measurement of senescence-associated β-galactosidase (SA-β-gal) activity, Ago2 translocation by Ago2/ Ki67 immunofluorescence ...
The Journal of allergy and clinical immunology, Jan 27, 2018
Immune checkpoints are accessory molecules that either promote or inhibit T-cell activation. Two ... more Immune checkpoints are accessory molecules that either promote or inhibit T-cell activation. Two inhibitory molecules, cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1), got high attention, as inhibition of CTLA-4 or PD-1 signaling provides the first immune therapy that significantly improves the survival of patients with metastatic solid cancers. Inhibition of CTLA-4 or PD-1 was first studied in and approved for patients with metastatic melanoma. Blocking immune checkpoints is also efficient in non-small-cell lung cancer, renal cell cancers, hypermutated gastrointestinal cancers, and others. Immune responses, whether directed against infections or against tumors, are divided into 2 phases: an initiation phase and an activation phase, where the immune system recognizes a danger signal and becomes activated by innate signals to fight the danger. This reaction is fundamental for the control of infections and cancer, but needs to be turned off once th...
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Papers by Thomas Wieder