Tag: Veglia

PHILADELPHIA — (Feb. 28, 2024) — The lab of Filippo Veglia, Ph.D., at The Wistar Institute has discovered a previously unknown mechanism for how aggressive brain cancers reprogram immune system cells from fighting cancer to enabling further tumor growth. The team’s findings were published in the paper “Functional reprogramming of neutrophils within the brain tumor microenvironment by hypoxia-driven histone lactylation,” from Cancer Discovery.

Brain and nervous system tumors are some of cancer’s most lethal forms; someone diagnosed with this type of cancer has a roughly one in three chance of surviving the next five years. Certain immunotherapies that stimulate the immune system to target specific cancer markers have shown progress against several brain cancers, but in many cases (and even more frequently in the most severe forms of brain cancer, like glioblastoma), the presence of tumor-infiltrating neutrophils is the key factor that has prevented these therapies from working.

Neutrophils are a type of white blood cell that the immune system uses to attack cancer in its early stages. However, scientists have discovered that, if a tumor survives the body’s initial defenses and continues to grow, these tumor-associated neutrophils actually start to work for the tumor rather than against it by suppressing further anti-cancer interventions from the immune system.

Now, scientists know how glioblastoma reprograms tumor-infiltrating neutrophils. In their new paper, Wistar’s Dr. Filippo Veglia and his team set out to understand the mechanisms behind brain cancer’s reprogramming of neutrophils — and how to stop it.

Researchers investigated the subset of neutrophils found almost exclusively within the brain tumor in preclinical models of brain cancer. Analysis showed that 25-30% of these tumor-infiltrating neutrophils expressed the CD71 protein, which was notably absent from most of the other neutrophils outside the brain tumor.

The team tested the immunosuppressive activity of intra-tumor CD71 positive (CD71⁺) neutrophils and found that they reduced immune system activity where CD71 negative (CD71^–) neutrophils did not. These immunosuppressive effects, the team found, were heightened in hypoxic (oxygen-deprived) environments like the hypoxic regions within the tumor where CD71⁺ neutrophils occur. Further analysis revealed that hypoxic CD71⁺ neutrophils expressed an additional gene, ARG1, that caused the immunosuppressive effect. Without ARG1, even hypoxic CD71⁺ neutrophils did not suppress the immune system, according to the researchers’ analysis.

The hypoxic CD71⁺ neutrophils had come to acquire ARG1 expression and its immunosuppressive effects, but researchers did not yet know how. Dr. Veglia and team suspected an interplay between hypoxia and neutrophils’ glucose metabolism was the root cause; the original suspect group of neutrophils from within the brain tumor (hypoxic CD71⁺ neutrophils) had shown increased indicators of glucose metabolism and lactate accumulation.

By inhibiting both glucose metabolism and the hypoxic CD71⁺ neutrophils’ ability to process lactate, researchers eliminated the neutrophils’ ability to suppress immune responses, which proved that both glucose metabolism and lactate accumulation were critical to the immunosuppressive reprogramming.

At this point, researchers knew that hypoxic CD71⁺ neutrophils, through glucose metabolism and lactate accumulation, acquired ARG1 expression, which would cause the neutrophils to suppress the immune system.

One crucial question remained: why would glucose metabolism and lactate accumulation cause ARG1 to be expressed?

The research team drew from an influential study that showed how gene expression could be changed through a process called histone lactylation. Histones are proteins that govern the structure of our genes, and certain changes to histones can cause genes to be turned on or off. In histone lactylation, incompletely metabolized lactate produces by-products that attach molecules called lactyl groups to histones, and those modified histones cause changes in gene expression.

When researchers looked for signs of this histone lactylation in hypoxic CD71⁺ neutrophils, they confirmed their suspicions. Not only did the CD71⁺ neutrophils show higher levels of histone lactylation markers than CD71^– neutrophils — the histone lactylation markers were high in the region of the ARG1 gene, an indication that the histone lactylation process had caused the ARG1 gene to be turned on. By selectively turning off the neutrophils’ ability to carry out histone lactylation, the researchers successfully reduced ARG1 expression.

Dr. Veglia and team discovered the central process causing neutrophil reprogramming: neutrophils infiltrate the brain tumor; hypoxic tumor regions recruit neutrophils, including those expressing CD71; the hypoxic CD71⁺ neutrophils increase their glucose metabolism, which causes lactate production to increase; the excess lactate causes histone lactylation; the histone lactylation causes ARG1 expression; and the ARG1 expression suppresses the activity and signaling of other immune cells.

Using their knowledge of the neutrophil reprogramming process, the team developed a therapeutic approach to stop the pro-cancer effect. They used the anti-epileptic compound isosafrole, which inhibited a key lactate-processing enzyme. In preclinical laboratory testing, isosafrole treatment reduced histone lactylation, resulting in an impaired ARG1 expression and immunosuppression of hypoxic CD71⁺ neutrophils, without negatively affecting other immune cells. By combining isosafrole treatment with a targeted brain cancer immunotherapy — which has previously struggled to succeed due to the cancer’s immunosuppression — Dr. Veglia and team overcame the resistance to immunotherapy and substantially slowed tumor progression in preclinical models.

“Our work shows the step-by-step process of how brain tumors can cause an immune system’s neutrophils to become deadly barriers to cancer treatment,” said Dr. Veglia. “Now that we understand this reprogramming process, we know how to interrupt it, and already, preclinical data show that isosafrole treatment that disrupts neutrophil reprogramming can make poor-prognosis brain tumors responsive to immunotherapy. We look forward to seeing how future research can refine this strategy to fight some of the deadliest cancers.”

Authors: Alessio Ugolini^1,2,3, Alessandra De Leo^1,2, Xiaoqing Yu¹, Fabio Scirocchi^1,3,4, Xiaoxian Liu¹, Barbara Peixoto^1,2, Delia Scocozza¹, Angelica Pace³, Michela Perego², Alessandro Gardini², Luca D’Angelo³, James K. C. Liu¹, Arnold B. Etame¹, Aurelia Rughetti³, Marianna Nuti³, Antonio Santoro³, Michael A. Vogelbaum¹, Jose R. Conejo-Garcia⁵, Paulo C. Rodriguez¹, and Filippo Veglia^1,2

¹H. Lee Moffitt Cancer Center

²The Wistar Institute

³Sapienza University of Rome

⁴Bambino Gesù Children’s Hospital

⁵Duke School of Medicine

Work supported by: This work was supported by The Ben & Catherine Ivy Foundation Emerging Adult Glioma Award; National Institutes of Health grants R01 NS131912, P30 CA076292, and P30 CA010815; PRIN 2022 grant 2022M5LBKP; and Sapienza University of Rome grant RM1221816BCE0EAA.

Publication information: “Functional reprogramming of neutrophils within the brain tumor microenvironment by hypoxia-driven histone lactylation,” from Cancer Discovery.

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PHILADELPHIA — (May 3, 2024) — The Wistar Institute assistant professor Filippo Veglia, Ph.D., and team, have discovered a key mechanism of how glioblastoma — a serious and often fatal brain cancer — suppresses the immune system so that the tumor can grow unimpeded by the body’s defenses. The lab’s discovery was published in the paper, “Glucose-driven histone lactylation promotes the immunosuppressive activity of monocyte-derived macrophages in glioblastoma,” in the journal Immunity.

“Our study shows that the cellular mechanisms of cancer’s self-preservation, when sufficiently understood, can be used against the disease very effectively,” said Dr. Veglia. “I look forward to future research on metabolism-driven mechanisms of immunosuppression in glioblastoma, and I’m hopeful for all that we will continue to learn about how to best understand and fight this cancer.”

Until now, it has been poorly understood how monocyte-derived macrophages and microglia create an immunosuppressive tumor microenvironment in glioblastoma. The Veglia lab investigated the cellular “how” of glioblastoma immunosuppression and identified that, as glioblastoma progressed, monocyte-derived macrophages came to outnumber microglia — which indicated that monocyte-derived macrophages’ eventuality to becoming the majority in the tumor microenvironment was advantageous to the cancer’s goal of evading immune response. Indeed, monocyte-derived macrophages, but not microglia, blocked the activity of T cells (immune cells that destroy tumor cells), in preclinical models and patients. The team confirmed this finding when they assessed preclinical models of glioblastoma with artificially reduced numbers of monocyte-derived macrophages. And as the group expected, the models with fewer malicious macrophages in the tumor microenvironment showed improved outcomes relative to the standard glioblastoma models.

Glioblastoma accounts for slightly more than half of all malignancies that originate in the brain, and the prognosis for those diagnosed with the cancer is quite poor: only 25% of patients who receive a glioblastoma diagnosis will survive beyond a year. Glioblastoma is inherently dangerous due to its location in the brain and its immunosuppressive tumor microenvironment, which renders glioblastoma resistant to promising immunotherapies. By programming certain immune cells like macrophages, (such as monocyte-derived macrophages and microglia), to work for — rather than against — the tumor, glioblastoma fosters a tumor microenvironment for itself that enables the cancer to grow aggressively while evading anticancer immune responses.

Having confirmed the role of monocyte-derived macrophages, the Veglia lab then sought to understand just how the cancer-allied immune cells were working against the immune system. They sequenced the macrophages in question to see whether the cells had any aberrant gene expression patterns that could point to which gene(s) could be playing a role in immunosuppression, and they also investigated the metabolic patterns of macrophages to see whether the macrophages’ nonstandard gene expression could be tied to metabolism.

The team’s twin gene expression & metabolic analysis led them to glucose metabolism. Through a series of tests, the Veglia lab was able to determine that monocyte-derived macrophages with enhanced glucose metabolism and expressing GLUT1, a major transporter for glucose (a key metabolic compound), blocked T cells’ function by releasing interleukin-10 (IL-10). The team demonstrated that glioblastoma-perturbed glucose metabolism in these macrophages induced their immunosuppressive activity.

The team discovered the key to macrophages’ glucose-metabolism-driven immunosuppressive potency lies in a process called “histone lactylation.” Histones are structural proteins in the genome that play a key role in which genes — like IL-10 — are expressed in which contexts. As rapidly glucose-metabolizing cells, monocyte-derived macrophages produce lactate, a by-product of glucose metabolism. And histones can become “lactylated” (which is when lactate becomes incorporated into histones) in such a way that the histones’ organization further promotes the expression of IL-10 — which is effectively produced by monocyte-derived macrophages to help cancer cells to grow.

But how can the glucose-driven immunosuppressive activity of monocyte-derived macrophages be stopped? Dr. Veglia and his research team identified a possible solution: PERK, an enzyme they had identified as regulating glucose metabolism and GLUT1 expression in macrophages. In preclinical models of glioblastoma, targeting PERK impaired histone lactylation and immunosuppressive activity of macrophages, and in combination with immunotherapy blocked glioblastoma progression and induced long-lasting immunity that protected the brain from tumor re-growth — a sign that targeting PERK-histone lactylation axis may be a viable strategy for fighting this deadly brain cancer.

Note: The work detailed in this publication was initiated at The H. Lee Moffitt Cancer Center during Dr. Veglia’s time there and continued at Wistar.

Co-authors: Alessandra De Leo, Alessio Ugolini, Fabio Scirocchi, Delia Scocozza, Barbara Peixoto, Paulo C. Rodriguez, and Filippo Veglia of the Department of Immunology at the H. Lee Moffitt Cancer Center; James K. C. Liu, Arnold B. Etame, Michael A. Vogelbaum, and Filippo Veglia of the Department of Neuro-Oncology at the H. Lee Moffitt Cancer Center; Xiaoqing Yu of the Department of Biostatistics and Bioinformatics at the H. Lee Moffitt Cancer Center; Alessandra De Leo, Alessio Ugolini, Barbara Peixoto and Filippo Veglia of The Wistar Institute; Alessio Ugolini, Fabio Scirocchi, Angelica Pace, Aurelia Rughetti and Marianna Nuti of the Department of Experimental Medicine at Sapienza University of Rome; Luca D’Angelo and Antonio Santoro of the Department of Human Neurosciences at Sapienza University of Rome; and Jose R. Conejo-Garcia of Duke School of Medicine.

Work supported by: This work was supported by The Ben & Catherine Ivy Foundation Emerging Adult Glioma Award, The National Institute of Neurological Disorders and Stroke (1R01NS131912-01), by American Cancer Society Institutional Research Grant (IRG-21-145-25). It is supported in part by the Flow Cytometry Core Facility, the Molecular Genomics Core, Proteomics & Metabolomics Core Facility, Biostatistics and Bioinformatics Shared Resource at the H. Lee Moffitt Cancer Center & Research Institute, a Comprehensive Cancer Center designated by the National Cancer Institute and funded in part by Support Grant (P30-CA076292). Human specimen collection (Policlinico Umberto I) was in part supported by grant RM120172B803DB14.

Publication information: “Glucose-driven histone lactylation promotes the immunosuppressive activity of monocyte-derived macrophages in glioblastoma,” from Immunity.

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