DIRECT AND INDIRECT MODULATION OF MACROPHAGES IN THE TUMOR MICROENVIRONMENT UPON GENOTOXIC STRESS ALTERS PHAGOCYTIC FUNCTION
(Abstract release date: 05/19/16)
EHA Library. Vorholt D. 06/09/16; 132574; E1025
Dr. Daniela Vorholt
Contributions
Contributions
Abstract
Abstract: E1025
Type: Eposter Presentation
Background
Resistance against chemotherapy is a central problem in the current treatment of B cell malignancies. Up until now, little is known about the impact of the tumor microenvironment on therapeutic outcome. This microenvironment consists of many different kinds of cells varying between tumors, significantly manipulating malignancy and enabling relapses after treatment. Macrophages are present in the microenvironment of most tumors – designated as tumor associated macrophages (TAM) – and are often correlated to a poor prognosis. We postulate that macrophages and their reprogramming are an essential element in the malignant progression of tumors and their response to DNA damage as occurring in chemotherapeutic treatment and are a promising target to improve therapy response.
Aims
We aim to define the functional characteristics of macrophages in their cross talk with malignant B cells and characterize their role for disease progression and antitumor therapy. Our particular interest lies on the investigation of the functional mechanistic and kinetics underlying macrophage repolarisation. Here, we intend to identify key regulators and their upstream signaling pathways by focusing on the DNA damage pathway.
Methods
To assess macrophage leukemia cell interaction we established in vitro and ex vivo co-cultures of macrophages and leukemic cells, specifically investigating macrophage antibody dependent cellular phagocytic (ADCP) capacities. Leukemic cell clearance and macrophage phenotype characterization are determined by flow cytometry. We addressed both primary CLL patient cells as well as humanized mouse model of BCL2/MYC double hit lymphoma.
Results
Functionally we prove that low dose application of the in vitro equivalent of Cyclophosphamide, Mafosfamide significantly increases the phagocytic function of macrophages. Besides this direct effect on macrophages, a combination of cyclophosphamide and alemtuzumab was demonstrated to induce a macrophage based increase in tumor clearance by cytokine secretion of stressed malignant B cells. Here, we could determine IL10 as an inducer of increased phagocytosis in tumor associated macrophages. Moreover we show that IL10 modulates differentiation of macrophages which strongly increases their ADCP compared to classical M1/M2 differentiated macrophages. Analyzing the functional contribution of the DNA-damage pathway we could identify pronounced secretion of IL10 in p53-deficient leukemia cellsWe show in vitro that the DNA damage pathway plays an important role in the ASAP mechanism as a down regulation of various DNA damage key players in the leukemic cells diminishes the stimulating effect of Cyclophosphamide and antibody combinations.
Conclusion
Repolarisation of macrophages towards increased phagocytosis is essential in immunochemotherapies. We demonstrate that the DNA damage pathway is important for this stimulating effect and that the mechanism involves a complex interplay between macrophages and leukemic cells. The DNA damage of the genotoxic chemotherapy is increasing the phagocytosis activity of the macrophages directly as well as indirect by a cytokine secreted from stressed leukemic cells.
Session topic: E-poster
Keyword(s): Antibody targeting, DNA damage, Macrophage, Microenvironment
Type: Eposter Presentation
Background
Resistance against chemotherapy is a central problem in the current treatment of B cell malignancies. Up until now, little is known about the impact of the tumor microenvironment on therapeutic outcome. This microenvironment consists of many different kinds of cells varying between tumors, significantly manipulating malignancy and enabling relapses after treatment. Macrophages are present in the microenvironment of most tumors – designated as tumor associated macrophages (TAM) – and are often correlated to a poor prognosis. We postulate that macrophages and their reprogramming are an essential element in the malignant progression of tumors and their response to DNA damage as occurring in chemotherapeutic treatment and are a promising target to improve therapy response.
Aims
We aim to define the functional characteristics of macrophages in their cross talk with malignant B cells and characterize their role for disease progression and antitumor therapy. Our particular interest lies on the investigation of the functional mechanistic and kinetics underlying macrophage repolarisation. Here, we intend to identify key regulators and their upstream signaling pathways by focusing on the DNA damage pathway.
Methods
To assess macrophage leukemia cell interaction we established in vitro and ex vivo co-cultures of macrophages and leukemic cells, specifically investigating macrophage antibody dependent cellular phagocytic (ADCP) capacities. Leukemic cell clearance and macrophage phenotype characterization are determined by flow cytometry. We addressed both primary CLL patient cells as well as humanized mouse model of BCL2/MYC double hit lymphoma.
Results
Functionally we prove that low dose application of the in vitro equivalent of Cyclophosphamide, Mafosfamide significantly increases the phagocytic function of macrophages. Besides this direct effect on macrophages, a combination of cyclophosphamide and alemtuzumab was demonstrated to induce a macrophage based increase in tumor clearance by cytokine secretion of stressed malignant B cells. Here, we could determine IL10 as an inducer of increased phagocytosis in tumor associated macrophages. Moreover we show that IL10 modulates differentiation of macrophages which strongly increases their ADCP compared to classical M1/M2 differentiated macrophages. Analyzing the functional contribution of the DNA-damage pathway we could identify pronounced secretion of IL10 in p53-deficient leukemia cellsWe show in vitro that the DNA damage pathway plays an important role in the ASAP mechanism as a down regulation of various DNA damage key players in the leukemic cells diminishes the stimulating effect of Cyclophosphamide and antibody combinations.
Conclusion
Repolarisation of macrophages towards increased phagocytosis is essential in immunochemotherapies. We demonstrate that the DNA damage pathway is important for this stimulating effect and that the mechanism involves a complex interplay between macrophages and leukemic cells. The DNA damage of the genotoxic chemotherapy is increasing the phagocytosis activity of the macrophages directly as well as indirect by a cytokine secreted from stressed leukemic cells.
Session topic: E-poster
Keyword(s): Antibody targeting, DNA damage, Macrophage, Microenvironment
Abstract: E1025
Type: Eposter Presentation
Background
Resistance against chemotherapy is a central problem in the current treatment of B cell malignancies. Up until now, little is known about the impact of the tumor microenvironment on therapeutic outcome. This microenvironment consists of many different kinds of cells varying between tumors, significantly manipulating malignancy and enabling relapses after treatment. Macrophages are present in the microenvironment of most tumors – designated as tumor associated macrophages (TAM) – and are often correlated to a poor prognosis. We postulate that macrophages and their reprogramming are an essential element in the malignant progression of tumors and their response to DNA damage as occurring in chemotherapeutic treatment and are a promising target to improve therapy response.
Aims
We aim to define the functional characteristics of macrophages in their cross talk with malignant B cells and characterize their role for disease progression and antitumor therapy. Our particular interest lies on the investigation of the functional mechanistic and kinetics underlying macrophage repolarisation. Here, we intend to identify key regulators and their upstream signaling pathways by focusing on the DNA damage pathway.
Methods
To assess macrophage leukemia cell interaction we established in vitro and ex vivo co-cultures of macrophages and leukemic cells, specifically investigating macrophage antibody dependent cellular phagocytic (ADCP) capacities. Leukemic cell clearance and macrophage phenotype characterization are determined by flow cytometry. We addressed both primary CLL patient cells as well as humanized mouse model of BCL2/MYC double hit lymphoma.
Results
Functionally we prove that low dose application of the in vitro equivalent of Cyclophosphamide, Mafosfamide significantly increases the phagocytic function of macrophages. Besides this direct effect on macrophages, a combination of cyclophosphamide and alemtuzumab was demonstrated to induce a macrophage based increase in tumor clearance by cytokine secretion of stressed malignant B cells. Here, we could determine IL10 as an inducer of increased phagocytosis in tumor associated macrophages. Moreover we show that IL10 modulates differentiation of macrophages which strongly increases their ADCP compared to classical M1/M2 differentiated macrophages. Analyzing the functional contribution of the DNA-damage pathway we could identify pronounced secretion of IL10 in p53-deficient leukemia cellsWe show in vitro that the DNA damage pathway plays an important role in the ASAP mechanism as a down regulation of various DNA damage key players in the leukemic cells diminishes the stimulating effect of Cyclophosphamide and antibody combinations.
Conclusion
Repolarisation of macrophages towards increased phagocytosis is essential in immunochemotherapies. We demonstrate that the DNA damage pathway is important for this stimulating effect and that the mechanism involves a complex interplay between macrophages and leukemic cells. The DNA damage of the genotoxic chemotherapy is increasing the phagocytosis activity of the macrophages directly as well as indirect by a cytokine secreted from stressed leukemic cells.
Session topic: E-poster
Keyword(s): Antibody targeting, DNA damage, Macrophage, Microenvironment
Type: Eposter Presentation
Background
Resistance against chemotherapy is a central problem in the current treatment of B cell malignancies. Up until now, little is known about the impact of the tumor microenvironment on therapeutic outcome. This microenvironment consists of many different kinds of cells varying between tumors, significantly manipulating malignancy and enabling relapses after treatment. Macrophages are present in the microenvironment of most tumors – designated as tumor associated macrophages (TAM) – and are often correlated to a poor prognosis. We postulate that macrophages and their reprogramming are an essential element in the malignant progression of tumors and their response to DNA damage as occurring in chemotherapeutic treatment and are a promising target to improve therapy response.
Aims
We aim to define the functional characteristics of macrophages in their cross talk with malignant B cells and characterize their role for disease progression and antitumor therapy. Our particular interest lies on the investigation of the functional mechanistic and kinetics underlying macrophage repolarisation. Here, we intend to identify key regulators and their upstream signaling pathways by focusing on the DNA damage pathway.
Methods
To assess macrophage leukemia cell interaction we established in vitro and ex vivo co-cultures of macrophages and leukemic cells, specifically investigating macrophage antibody dependent cellular phagocytic (ADCP) capacities. Leukemic cell clearance and macrophage phenotype characterization are determined by flow cytometry. We addressed both primary CLL patient cells as well as humanized mouse model of BCL2/MYC double hit lymphoma.
Results
Functionally we prove that low dose application of the in vitro equivalent of Cyclophosphamide, Mafosfamide significantly increases the phagocytic function of macrophages. Besides this direct effect on macrophages, a combination of cyclophosphamide and alemtuzumab was demonstrated to induce a macrophage based increase in tumor clearance by cytokine secretion of stressed malignant B cells. Here, we could determine IL10 as an inducer of increased phagocytosis in tumor associated macrophages. Moreover we show that IL10 modulates differentiation of macrophages which strongly increases their ADCP compared to classical M1/M2 differentiated macrophages. Analyzing the functional contribution of the DNA-damage pathway we could identify pronounced secretion of IL10 in p53-deficient leukemia cellsWe show in vitro that the DNA damage pathway plays an important role in the ASAP mechanism as a down regulation of various DNA damage key players in the leukemic cells diminishes the stimulating effect of Cyclophosphamide and antibody combinations.
Conclusion
Repolarisation of macrophages towards increased phagocytosis is essential in immunochemotherapies. We demonstrate that the DNA damage pathway is important for this stimulating effect and that the mechanism involves a complex interplay between macrophages and leukemic cells. The DNA damage of the genotoxic chemotherapy is increasing the phagocytosis activity of the macrophages directly as well as indirect by a cytokine secreted from stressed leukemic cells.
Session topic: E-poster
Keyword(s): Antibody targeting, DNA damage, Macrophage, Microenvironment
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