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 ▲]

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 ▲]

Prognostic and Predictive Molecular Biomarkers for Colorectal Cancer: Updates and Challenges

in Cancers (2020)

Colorectal cancer (CRC) is a leading cause of death among cancer patients. This heterogeneous disease is characterized by alterations in multiple molecular pathways throughout its development. Mutations ... [more ▼]

Colorectal cancer (CRC) is a leading cause of death among cancer patients. This heterogeneous disease is characterized by alterations in multiple molecular pathways throughout its development. Mutations in RAS, along with the mismatch repair gene deficiency, are currently routinely tested in clinics. Such biomarkers provide information for patient risk stratification and for the choice of the best treatment options. Nevertheless, reliable and powerful prognostic markers that can identify “high-risk” CRC patients, who might benefit from adjuvant chemotherapy, in early stages, are currently missing. To bridge this gap, genomic information has increasingly gained interest as a potential method for determining the risk of recurrence. However, due to several limitations of gene-based signatures, these have not yet been clinically implemented. In this review, we describe the different molecular markers in clinical use for CRC, highlight new markers that might become indispensable over the next years, discuss recently developed gene expression-based tests and highlight the challenges in biomarker research. [less ▲]

Hypoxia- and MicroRNA-Induced Metabolic Reprogramming of Tumor-Initiating Cells

in Cells (2019), 8(6),

Colorectal cancer (CRC), the second most common cause of cancer mortality in theWestern world, is a highly heterogeneous disease that is driven by a rare subpopulation of tumorigenic cells, known as ... [more ▼]

Colorectal cancer (CRC), the second most common cause of cancer mortality in theWestern world, is a highly heterogeneous disease that is driven by a rare subpopulation of tumorigenic cells, known as cancer stem cells (CSCs) or tumor-initiating cells (TICs). Over the past few years, a plethora of di erent approaches, aimed at identifying and eradicating these self-renewing TICs, have been described. A focus on the metabolic and bioenergetic di erences between TICs and less aggressive di erentiated cancer cells has thereby emerged as a promising strategy to specifically target the tumorigenic cell compartment. Extrinsic factors, such as nutrient availability or tumor hypoxia, are known to influence the metabolic state of TICs. In this review, we aim to summarize the current knowledge on environmental stress factors and how they a ect the metabolism of TICs, with a special focus on microRNA (miRNA)- and hypoxia-induced e ects on colon TICs. [less ▲]

Tumor suppressor miR-215 counteracts hypoxia-induced colon cancer stem cell activity

in Cancer Letters (2019), 450

Cancer stem cells, also known as tumor-initiating cells (TICs), are a population of aggressive and self-renewing cells that are responsible for the initiation and progression of many cancers, including ... [more ▼]

Cancer stem cells, also known as tumor-initiating cells (TICs), are a population of aggressive and self-renewing cells that are responsible for the initiation and progression of many cancers, including colorectal carcinoma. Intratumoral hypoxia, i.e. reduced oxygen supply following uncontrolled proliferation of cancer cells, is thought to support TIC activity by inducing specific hypoxia-responsive mechanisms that are not yet entirely understood. Using previously established and fully characterized patient-derived TIC cultures, we could observe increased sphere and colony formation under hypoxic conditions. Mechanistically, microRNA (miRNA)-profiling experiments allowed us to identify miR-215 as one of the main hypoxia-induced miRNAs in primary colon TICs. Through stable overexpression of miR-215, followed by a set of functional in vitro and in vivo investigations, miR-215 was pinpointed as a negative feedback regulator, working against the TIC-promoting effects of hypoxia. Furthermore, we could single out LGR5, a bona fide marker of non-neoplastic intestinal stem cells, as a downstream target of hypoxia/miR-215 signaling. The strong tumor- and TIC-suppressor potential of miR-215 and the regulatory role of the hypoxia/miR-215/LGR5 axis may thus represent interesting points of attack for the development of innovative anti-CSC therapy approaches. [less ▲]

In search of definitions: Cancer-associated fibroblasts and their markers

in International Journal of Cancer (2019)

The tumor microenvironment has been identified as one of the driving factors of tumor progression and invasion. Inside this microenvironment, cancer-associated fibroblasts (CAFs), a type of perpetually ... [more ▼]

The tumor microenvironment has been identified as one of the driving factors of tumor progression and invasion. Inside this microenvironment, cancer-associated fibroblasts (CAFs), a type of perpetually activated fibroblasts, have been implicated to have a strong tumor-modulating effect and play a key role in areas such as drug resistance. Identification of CAFs has typically been carried based on the expression of various "CAF markers", such as fibroblast activation protein alpha (FAP) and alpha smooth muscle actin (αSMA), which separates them from the larger pool of fibroblasts present in the body. However, as outlined in this Review, the expression of various commonly used fibroblast markers is extremely heterogeneous and varies strongly between different CAF subpopulations. As such, novel selection methods based on cellular function, as well as further characterizing research, are vital for the standardization of CAF identification in order to improve the cross-applicability of different research studies in the field. The aim of this review is to give a thorough overview of the commonly used fibroblast markers in the field and their various strengths and, more importantly, their weaknesses, as well as to highlight potential future avenues for CAF identification and targeting. [less ▲]

The PD-L1- and IL6-mediated dampening of the IL27/STAT1 anticancer responses are prevented by a-PD-L1 or a-IL6 antibodies

in Journal of Leukocyte Biology (2018), 104

Interleukin-27 (IL27) is a type-I cytokine of the IL6/IL12 family and is predominantly secreted by activated macrophages and dendritic cells.We show that IL27 induces STAT factor phosphorylation in ... [more ▼]

Interleukin-27 (IL27) is a type-I cytokine of the IL6/IL12 family and is predominantly secreted by activated macrophages and dendritic cells.We show that IL27 induces STAT factor phosphorylation in cancerous cell lines of different tissue origin. IL27 leads to STAT1 phosphorylation and recapitulates an IFN-𝛾-like response in the microarray analyses, with up-regulation of genes involved in antiviral defense, antigen presentation, and immune suppression. Like IFN-𝛾, IL27 leads to an up-regulation of TAP2 and MHC-I proteins, which mediate increased tumor immune clearance. However, both cytokines also upregulate proteins such as PD-L1 (CD274) and IDO-1, which are associatedwith immune escape of cancer. Interestingly, differential expression of these geneswas observed within the different cell lines and when comparing IL27 to IFN-𝛾. In coculture experiments of hepatocellular carcinoma (HCC) cells with peripheral blood mononuclear cells, pre-treatment of the HCC cells with IL27 resulted in lowered IL2 production by anti-CD3/-CD28 activated T-lymphocytes. Addition of anti-PD-L1 antibody, however, restored IL2 secretion. The levels of other TH1 cytokines were also enhanced or restored upon administration of anti-PD-L1. In addition, we show that the suppression of IL27 signaling by IL6-type cytokine prestimulation— mimicking a situation occurring, for example, in IL6-secreting tumors or in tumor inflammation–induced cachexia—can be antagonized by antibodies against IL6-type cytokines or their receptors. Therapeutically, the antitumor effects of IL27 (mediated, e.g., by increased antigen presentation) might thus be increased by combining IL27with blocking antibodies against PD-L1 or/and IL6-type cytokines. [less ▲]

Loss of Myosin Vb in colorectal cancer is a strong prognostic factor for disease recurrence

in British Journal of Cancer (2017), 117(11), 1689-1701

Background: Selecting the most beneficial treatment regimens for colorectal cancer (CRC) patients remains challenging due to a lack of prognostic markers. Members of the Myosin family, proteins recognized ... [more ▼]

Background: Selecting the most beneficial treatment regimens for colorectal cancer (CRC) patients remains challenging due to a lack of prognostic markers. Members of the Myosin family, proteins recognized to play a major role in trafficking and polarization of cells, have recently been reported to be closely associated with several types of cancer and might thus serve as potential prognostic markers in the context of CRC. Methods: We used a previously established meta-analysis of publicly available gene expression data to analyse the expression of different members of the Myosin V family, namely MYO5A, 5B, and 5C, in CRC. Using laser-microdissected material as well as tissue microarrays from paired human CRC samples, we validated both RNA and protein expression of MYO5B and its known adapter proteins (RAB8A and RAB25) in an independent patient cohort. Finally, we assessed the prognostic value of both MYO5B and its adapter-coupled combinatorial gene expression signatures. Results: The meta-analysis as well as an independent patient cohort study revealed a methylation-independent loss of MYO5B expression in CRC that matched disease progression. Although MYO5B mutations were identified in a small number of patients, these cannot be solely responsible for the common down-regulation observed in CRC patients. Significantly, CRC patients with low MYO5B expression displayed shorter overall, disease- and metastasis-free survival, a trend that was further reinforced when RAB8A expression was also taken into account. Conclusions: Our data identifies MYO5B as a powerful prognostic biomarker in CRC, especially in early stages (stages I and II), which might help stratifying patients with stage II for adjuvant chemotherapy. [less ▲]

Tumor-Initiating Cells: a criTICal review of isolation approaches and new challenges in targeting strategies

in Molecular Cancer (2017)

Most cancers contain a subpopulation of highly tumorigenic cells, known as cancer stem cells (CSCs) or tumor-initiating cells (TICs). Targeting TICs may be essential to achieve cure, because of their self ... [more ▼]

Most cancers contain a subpopulation of highly tumorigenic cells, known as cancer stem cells (CSCs) or tumor-initiating cells (TICs). Targeting TICs may be essential to achieve cure, because of their self-renewal and tumorigenic properties as well as their resistance to conventional therapies. Despite significant advances in TIC biology, their isolation and identification remain largely disputed and incompletely established. In this review, we discuss the latest developments in isolation and culturing approaches of TICs, with focus on colorectal cancer (CRC). We feature recent findings on TIC-relevant signaling pathways and the metabolic identity of TICs, as well as their current clinical implications. Lastly, we highlight the influence of inter- and intra-tumoral heterogeneity on TIC function and targeting approaches. [less ▲]

Insights into ligand stimulation effects on gastro-intestinal stromal tumors signalling.

in Cell Signal (2017)

Mutations in KIT or PDGFRA are responsible for >85% of gastrointestinal stromal tumors. The introduction of imatinib in the GIST therapy scheme revolutionized the patient outcome. Unfortunately, the ... [more ▼]

Mutations in KIT or PDGFRA are responsible for >85% of gastrointestinal stromal tumors. The introduction of imatinib in the GIST therapy scheme revolutionized the patient outcome. Unfortunately, the therapy allows the disease stabilization instead of curation. Furthermore the resistance to the inhibitor arises in most cases within two first years of therapy. A thorough investigation of the signalling pathways activated by the major PDGFRA and KIT mutants encountered in the GIST landscape allowed to identify striking differences between the two receptor tyrosine kinases. PDGFRA mutants were not responsive to their ligand, PDGFAA, and displayed a high constitutive kinase activity. In contrast, all KIT mutants retained, in addition to their constitutive activation, the ability to be stimulated by their ligand. Kit mutants displayed a lower intrinsic kinase activity relative to PDGFRA mutants, while the KIT Exon 11 deletion mutant exhibited the highest intrinsic kinase activity among KIT mutants. At the transcriptomic level, the MAPK pathway was established as the most prominent activated pathway, which is commonly up-regulated by all PDGFRA and KIT mutants. Inhibition of this pathway, using the MEK inhibitor PD0325901, reduced the proliferation of GIST primary cells at nanomolar concentrations. Altogether, our data demonstrate the high value of MEK inhibitors for combination therapy in GIST treatment and more importantly the interest of evaluating the SCF expression profile in GIST patients presenting KIT mutations. [less ▲]