The gut microbial metabolite formate exacerbates colorectal cancer progression

in Nature Metabolism (2022)

The gut microbiome is a key player in the immunomodulatory and protumorigenic microenvironment during colorectal cancer (CRC), as different gut-derived bacteria can induce tumour growth. However, the ... [more ▼]

The gut microbiome is a key player in the immunomodulatory and protumorigenic microenvironment during colorectal cancer (CRC), as different gut-derived bacteria can induce tumour growth. However, the crosstalk between the gut microbiome and the host in relation to tumour cell metabolism remains largely unexplored. Here we show that formate, a metabolite produced by the CRC-associated bacterium Fusobacterium nucleatum, promotes CRC development. We describe molecular signatures linking CRC phenotypes with Fusobacterium abundance. Cocultures of F. nucleatum with patient-derived CRC cells display protumorigenic effects, along with a metabolic shift towards increased formate secretion and cancer glutamine metabolism. We further show that microbiome-derived formate drives CRC tumour invasion by triggering AhR signalling, while increasing cancer stemness. Finally, F. nucleatum or formate treatment in mice leads to increased tumour incidence or size, and Th17 cell expansion, which can favour proinflammatory profiles. Moving beyond observational studies, we identify formate as a gut-derived oncometabolite that is relevant for CRC progression. [less ▲]

Mitochondria preserve an autarkic one-carbon cycle to confer growth-independent cancer cell migration and metastasis

in Nature Communications (2022)

Metastasis is the most common cause of death in cancer patients. Canonical drugs target mainly the proliferative capacity of cancer cells, which leaves slow-proliferating, persistent cancer cells ... [more ▼]

Metastasis is the most common cause of death in cancer patients. Canonical drugs target mainly the proliferative capacity of cancer cells, which leaves slow-proliferating, persistent cancer cells unaffected. Metabolic determinants that contribute to growth-independent functions are still poorly understood. Here we show that antifolate treatment results in an uncoupled and autarkic mitochondrial one-carbon (1C) metabolism during cytosolic 1C metabolism impairment. Interestingly, antifolate dependent growth-arrest does not correlate with decreased migration capacity. Therefore, using methotrexate as a tool compound allows us to disentangle proliferation and migration to profile the metabolic phenotype of migrating cells. We observe that increased serine de novo synthesis (SSP) supports mitochondrial serine catabolism and inhibition of SSP using the competitive PHGDH-inhibitor BI-4916 reduces cancer cell migration. Furthermore, we show that sole inhibition of mitochondrial serine catabolism does not affect primary breast tumor growth but strongly inhibits pulmonary metastasis. We conclude that mitochondrial 1C metabolism, despite being dispensable for proliferative capacities, confers an advantage to cancer cells by supporting their motility potential. [less ▲]

Understanding the role of Fusobacterium nucleatum metabolism in colon cancer initiation and progression

Poster (2020, February 22)

Accumulating evidence suggests that dysbiosis, a state of pathological imbalance in the human gut microbiome, is present in patients suffering from colorectal cancer (CRC). 16S rRNA gene sequencing, as ... [more ▼]

Accumulating evidence suggests that dysbiosis, a state of pathological imbalance in the human gut microbiome, is present in patients suffering from colorectal cancer (CRC). 16S rRNA gene sequencing, as well as metagenomic and metatranscriptomic analyses, identified specific bacteria being associated with CRC. Among others, Fusobacterium ssp. have been found to directly interact with cancer or immune cells of their host. However, only a limited number of CRC-associated microbes have been examined for host-microbial interactions and, as such, the role of bacteria in the etiology of the disease remains largely elusive. Our aim is the development of predictive and experimental models that allow to not only study the host-microbiota interactions but are also amenable to high-throughput experimentation and large-scale omics-data integration. Ultimately, such models should help to get from meta-omics to cellular mechanism and, moreover, serve as tools for reproducible analyses of host-microbial interaction mechanisms of on a transcriptomic, proteomic, and metabolomic level. Our research proposes an integrative study approach allowing us to bridge meta-omics with functional mechanisms by focusing on the interaction taking place between F. nucleatum and patient-derived CRC cells. [less ▲]

Myosins: Driving us towards novel targets and biomarkers in cancer

in Actin Cytoskeleton in Cancer Progression and Metastasis - Part B (2020)

The view that myosins, which are actin based molecular motors, are only driving muscle contraction evolved a lot during the last decades. Nowadays, it is known that they reshape the actin skeleton, anchor ... [more ▼]

The view that myosins, which are actin based molecular motors, are only driving muscle contraction evolved a lot during the last decades. Nowadays, it is known that they reshape the actin skeleton, anchor or transport vesicles, organelles as well as protein complexes. Here, we review how their role in cell division, polarization, migration and death is related to the cancer phenotype. We will further focus our attention on recent evidences suggesting that these central roles make them prime biomarker candidates for the prognosis of various cancers. Finally, we will discuss emerging evidences raising myosins as new therapeutic targets to fight malignant tumors. [less ▲]

Transcriptomic analyses of primary astrocytes under TNFα treatment

in Genomics Data (2015), 7

Astrocytes, the most abundant glial cell population in the central nervous system, have important functional roles in the brain as blood brain barrier maintenance, synaptic transmission or intercellular ... [more ▼]

Astrocytes, the most abundant glial cell population in the central nervous system, have important functional roles in the brain as blood brain barrier maintenance, synaptic transmission or intercellular communications. Numerous studies suggested that astrocytes exhibit a functional and morphological high degree of plasticity. For example, following any brain injury, astrocytes become reactive and hypertrophic. This phenomenon, also called reactive gliosis, is characterized by a set of progressive gene expression and cellular changes. Interestingly, in this context, astrocytes can re-acquire neurogenic properties. It has been shown that astrocytes can undergo dedifferentiation upon injury and inflammation, and may re-acquire the potentiality of neural progenitors. To assess the effect of inflammation on astrocytes, primary mouse astrocytes were treated with tumor necrosis factor α (TNFα), one of the main pro-inflammatory cytokines. The strength of this study is that pure primary astrocytes were used. As microglia are highly reactive immune cells, we used a magnetic cell sorting separation (MACS) method to further obtain highly pure astrocyte cultures devoid of microglia. Here, we provide details of the microarray data, which have been deposited in the Gene Expression Omnibus (GEO) under the series accession number GSE73022. The analysis and interpretation of these data are included in Gabel et al. (2015). Analysis of gene expression indicated that the NFκB pathway-associated genes were induced after a TNFα treatment. We have shown that primary astrocytes devoid of microglia can respond to a TNFα treatment with the re-expression of genes implicated in the glial cell development. [less ▲]

NLRP3 Inflammasome Is Expressed and Functional in Mouse Brain Microglia but Not in Astrocytes.

in PLoS ONE (2015), 10(6),

Neuroinflammation is the local reaction of the brain to infection, trauma, toxic molecules or protein aggregates. The brain resident macrophages, microglia, are able to trigger an appropriate response ... [more ▼]

Neuroinflammation is the local reaction of the brain to infection, trauma, toxic molecules or protein aggregates. The brain resident macrophages, microglia, are able to trigger an appropriate response involving secretion of cytokines and chemokines, resulting in the activation of astrocytes and recruitment of peripheral immune cells. IL-1β plays an important role in this response; yet its production and mode of action in the brain are not fully understood and its precise implication in neurodegenerative diseases needs further characterization. Our results indicate that the capacity to form a functional NLRP3 inflammasome and secretion of IL-1β is limited to the microglial compartment in the mouse brain. We were not able to observe IL-1β secretion from astrocytes, nor do they express all NLRP3 inflammasome components. Microglia were able to produce IL-1β in response to different classical inflammasome activators, such as ATP, Nigericin or Alum. Similarly, microglia secreted IL-18 and IL-1α, two other inflammasome-linked pro-inflammatory factors. Cell stimulation with α-synuclein, a neurodegenerative disease-related peptide, did not result in the release of active IL-1β by microglia, despite a weak pro-inflammatory effect. Amyloid-β peptides were able to activate the NLRP3 inflammasome in microglia and IL-1β secretion occurred in a P2X7 receptor-independent manner. Thus microglia-dependent inflammasome activation can play an important role in the brain and especially in neuroinflammatory conditions. [less ▲]