modeling-tumor-associated-macrophages-vitro-role-secreted-factors

Modeling Tumor-Associated Macrophages <em>In Vitro</em>: The Role of Secreted Factors in Tumor Microenvironment Dynamics

Macrophages exhibit remarkable plasticity, enabling them to acquire distinct functional states in response to a variety of environmental cues. In solid ...

Universidad de Buenos Aires

Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)

Small molecules targeting kinases involved in B cell receptor signaling are showing encouraging clinical activity in chronic lymphocytic leukemia (CLL) patients. Fostamatinib (R406) and entospletinib (GS-9973) are ATP-competitive inhibitors designed to target spleen tyrosine kinase (Syk) that have shown clinical activity with acceptable toxicity in trials with CLL patients. Preclinical studies with these inhibitors in CLL have focused on their effect in patient-derived leukemic B cells. In this work we show that clinically relevant doses of R406 and GS-9973 impaired the activation and proliferation of T cells from CLL patients. This effect could not be ascribed to Syk-inhibition given that we show that T cells from CLL patients do not express Syk protein. Interestingly, ζ-chain-associated protein kinase (ZAP)-70 phosphorylation was diminished by both inhibitors upon TCR stimulation on T cells. In addition, we found that both agents reduced macrophage-mediated phagocytosis of rituximab-coated CLL cells. Overall, these results suggest that in CLL patients treated with R406 or GS-9973 T cell functions, as well as macrophage-mediated anti-tumor activity of rituximab, might be impaired. The potential consequences for CLL-treated patients are discussed.

The kinase inhibitors R406 and GS-9973 impair T cell functions and macrophage-mediated anti-tumor activity of rituximab in chronic lymphocytic leukemia patients.

Sphingosine kinase 1 participates in the activation, proliferation and survival of chronic lymphocytic leukemia cells.

The proliferation and survival of malignant B cells in chronic lymphocytic leukemia (CLL) depend on signals from the microenvironment in lymphoid tissues. Among a plethora of soluble factors, IL-8 has been considered one of the most relevant to support CLL B cell progression in an autocrine fashion, even though the expression of IL-8 receptors, CXCR1 and CXCR2, on leukemic B cells has not been reported. Here we show that circulating CLL B cells neither express CXCR1 or CXCR2 nor they respond to exogenous IL-8 when cultured in vitro alone or in the presence of monocytes/nurse-like cells. By intracellular staining and ELISA we show that highly purified CLL B cells do not produce IL-8 spontaneously or upon activation through the B cell receptor. By contrast, we found that a minor proportion (<0.5%) of contaminating monocytes in enriched suspensions of leukemic cells might be the actual source of IL-8 due to their strong capacity to release this cytokine. Altogether our results indicate that CLL B cells are not able to secrete or respond to IL-8 and highlight the importance of methodological details in in vitro experiments.

Revisiting the role of interleukin-8 in chronic lymphocytic leukemia.

Autologous T-cell activation fosters ABT-199 resistance in chronic lymphocytic leukemia: rationale for a combined therapy with SYK inhibitors and anti-CD20 monoclonal antibodies.

Effect of the BTK inhibitor ibrutinib on macrophage- and γδ T cell-mediated response against Mycobacterium tuberculosis.

Ibrutinib is a BTK/ITK inhibitor with efficacy for the treatment of various lymphoid cancers, including CLL. Considering that innate and adaptative immune defects are a dominant feature of CLL patients, we evaluated whether  ibrutinib affects the survival and function of neutrophils and γδ T cells, key players of the early immune response against microbes. Neutrophils and γδ T cells were obtained from peripheral blood of healthy donors and CLL patients. We found that ibrutinib reduces the production of reactive oxygen species (ROS) and bacteria killing capacity, and slightly impairs neutrophil extracellular traps (NETs) production without affecting bacteria-uptake and CD62L-downregulation induced by fMLP or aggregated IgG. In addition, ibrutinib reduces γδ T cell activation and CD107a degranulation induced by phosphoantigens or anti-CD3. These findings are in agreement with previous data suggesting that ibrutinib interferes with the protective immune response to pathogens, particularly Mycobacteria and .

The effect of ibrutinib on neutrophil and γδ T cell functions.

Expression and function of cathelicidin hCAP18/LL-37 in chronic lymphocytic leukemia.

Langerhans cell histiocytosis (LCH) is characterized by an expansion and accumulation of pathological histiocytes expressing langerin (CD207) and CD1a in different organs under an inflammatory milieu. The origin of pathognomonic precursors of LCH is widely debated, but monocytes and pre-dendritic cells (pre-DC) play a significant role. Remarkably, we found an expansion of AXL cells in the CD11c subset of patients with active LCH, which also express the pathognomonic CD207 and CD1a. Moreover, we obtained a monocyte-derived LC-like (mo-LC-like) expressing high levels of AXL when treated with inflammatory cytokine, or plasma of patients with active disease. Intriguingly, inhibiting the mTOR pathway at the initial stages of monocyte differentiation to LC-like fosters the pathognomonic LCH program, highly increasing CD207 levels, together with NOTCH1 induction. We define here that AXL could also be taken as a strong pathognomonic marker for LCH, and the release of Langerin and NOTCH1 expression depends on the inhibition of the mTOR pathway.

Increased AXL myeloid cells as pathognomonic marker in Langerhans cell histiocytosis and Langerin expression dependence of mTOR inhibition.

Editorial: Myeloid cell reprogramming: molecular pathways involved in disease development.

Ketamine has emerged as a rapid and sustained treatment for Major Depressive Disorder (MDD) and an alternative for patients who have not responded to traditional therapies. Its effects have been partly attributed to the noncompetitive antagonism of the N-methyl-D-aspartate receptor (NMDAR) in the central nervous system, which enhances neuroplasticity. However, the etiopathology of MDD is complex, and substantial evidence suggests that inflammation may significantly contribute to the initiation and maintenance of MDD. Furthermore, the rapid and sustained antidepressant effect of ketamine may be attributed to its anti-inflammatory and immunomodulatory actions. To investigate the antidepressant and anti-inflammatory effect of ketamine, we used a lipopolysaccharide (LPS)-induced depressive-like murine model. The Tail Suspension Test (TST) and Sucrose Preference Test (SPT) were conducted to assess depressive-like behaviors. Additionally, cellular immunophenotyping of blood, spleen, and brain was performed by flow cytometry. Ketamine administration (10-20 mg/kg) alleviated despair and anhedonia in LPS-depressive-like mice, as evidenced by the TST and SPT tests. Behavioral changes were accompanied by the reduction of Ly6G neutrophils and an increment of anti-inflammatory Ly6C monocytes in the blood. Ketamine treatment also reduced CD45Ly6GLy6C monocyte infiltration into the brain and dampened microglial activation (CD45CD11b). In the spleen, ketamine decreased the expansion of acute T lymphocyte response (CD3CD4CD8) induced by LPS, while increasing the percentage of CD4CD69TIM-3 lymphocytes, known for their regulatory function. Splenic macrophages were also polarized towards an anti-inflammatory CD206M2-phenotype with ketamine. Finally, we showed that the anti-inflammatory and antidepressant effects are linked, perhaps as convergent outcomes, by using another NMDA receptor antagonist, MK-801, and the mTOR signaling inhibitor, rapamycin. These findings highlight ketamine's multifaceted mechanisms of action, underscoring its potential as a treatment for MDD, particularly in patients with significant inflammation.

Ketamine reduces microglial activation and brain monocyte infiltration and promotes peripheral regulatory immune cells, relieving lipopolysaccharide (LPS)-induced depressive-like behavior in mice.

Article	Year
The kinase inhibitors R406 and GS-9973 impair T cell functions and macrophage-mediated anti-tumor activity of rituximab in chronic lymphocytic leukemia patients. Cancer immunology, immunotherapy : CII\| PubMed ID: 28011996	2017
Sphingosine kinase 1 participates in the activation, proliferation and survival of chronic lymphocytic leukemia cells. Haematologica\| PubMed ID: 28360148	2017
Revisiting the role of interleukin-8 in chronic lymphocytic leukemia. Scientific reports\| PubMed ID: 29146966	2017
Autologous T-cell activation fosters ABT-199 resistance in chronic lymphocytic leukemia: rationale for a combined therapy with SYK inhibitors and anti-CD20 monoclonal antibodies. Haematologica\| PubMed ID: 29748439	2018
Effect of the BTK inhibitor ibrutinib on macrophage- and γδ T cell-mediated response against Mycobacterium tuberculosis. Blood cancer journal\| PubMed ID: 30397191	2018
The effect of ibrutinib on neutrophil and γδ T cell functions. Leukemia & lymphoma\| PubMed ID: 32306816	2020
Expression and function of cathelicidin hCAP18/LL-37 in chronic lymphocytic leukemia. Haematologica\| PubMed ID: 33054065	2020
Increased AXL myeloid cells as pathognomonic marker in Langerhans cell histiocytosis and Langerin expression dependence of mTOR inhibition. Clinical immunology (Orlando, Fla.)\| PubMed ID: 38575046	2024
Editorial: Myeloid cell reprogramming: molecular pathways involved in disease development. Frontiers in immunology\| PubMed ID: 38745655	2024
Ketamine reduces microglial activation and brain monocyte infiltration and promotes peripheral regulatory immune cells, relieving lipopolysaccharide (LPS)-induced depressive-like behavior in... Molecular psychiatry\| PubMed ID: 41254322	2025

Denise Risnik

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