Project description:It is becoming increasingly clear that tumor-associated neutrophils (TANs) play an important role in cancer biology, through direct impact on tumor growth and by recruitment of other cells types into the tumor. The function of neutrophils in cancer has been the subject of seemingly contradicting reports, pointing toward a dual role played by TANs in tumor progression. The existence of multiple neutrophil subsets, as well as phenotypic modulation of the neutrophils by various factors in the tumor microenvironment, has been shown. TGFβ plays a significant role in the determination of neutrophils' phenotype, by shifting the balance from an antitumor (N1) toward a more permissive (N2) phenotype. The full range of mechanisms responsible for the pro- vs. antitumor effects of TANs has not yet been elucidated. Therefore, the ability to identify the different neutrophil subpopulations in the tumor is critical in order to understand TANs evolution and contribution throughout tumor progression. Using a transcriptomic approach, we identified alternations in gene expression profile following TGFβ inhibition. We show that N1 and N2 TANs represent distinct subpopulations with different transcriptional signatures and both differ from naive bone marrow neutrophils. The analysis highlights a clear difference in pathways involved in neutrophil function such as cytoskeletal organization and antigen presentation, as well as alterations in chemokine profile, eventually affecting their effect on tumor cells and tumor growth. These data highlights several potential new pathways and mechanisms by which neutrophils can influence both the tumor cells and the adaptive immune system.
Project description:An acidic tumor microenvironment plays a critical role in tumor progression. However, understanding of metabolic reprogramming of tumors in response to acidic extracellular pH has remained elusive. Using comprehensive metabolomic analyses, we demonstrated that acidic extracellular pH (pH 6.8) leads to the accumulation of N1-acetylspermidine, a pro-tumor metabolite, through upregulation of the expression of spermidine/spermine acetyl transferase 1 (SAT1). Inhibition of SAT1 expression suppressed the accumulation of intra- and extracellular N1-acetylspermidine at acidic pH. Conversely, overexpression 3 of SAT1 increased intra- and extracellular N1-acetylspermidine levels, supporting the proposal that SAT1 is responsible for accumulation of N1-acetylspermidine. While inhibition of SAT1 expression only had a minor effect on cancer cell growth in vitro, SAT1 knockdown significantly decreased tumor growth in vivo, supporting a contribution of the SAT1-N1-acetylspermidine axis to pro-tumor immunity. Immune cell profiling revealed that inhibition of SAT1 expression decreased neutrophil recruitment to the tumor, resulting in impaired angiogenesis and tumor growth. We showed that anti-neutrophil neutralizing antibodies suppressed growth in control tumors to a similar extent to that seen in SAT1 knockdown tumors in vivo. Further, a SAT1 signature was found to be correlated with poor patient prognosis. Our findings demonstrate that extracellular acidity stimulates recruitment of pro-tumor neutrophils via the SAT1-N1-acetylspermidine axis, which may represent a novel target for anti-tumor immune therapy.
Project description:This model is an expansion of the Regan2022 - Mechanosensitive EMT model (MODEL2208050001); it includes a TGFβ signaling module and autocrine signaling in mesenchymal cells. The expanded 150-node (630 link) modular model undergoes EMT triggered by biomechanical and growth signaling crosstalk, or by TGFβ. As its predecessor, this model also reproduces the ability of the core EMT transcriptional network to maintain distinct epithelial, hybrid E/M and mesenchymal states, as well as EMT driven by mitogens such as EGF on stiff ECM. We also reproduce the observed lack of stepwise MET, in that our model's dynamics does not pass through the hybrid E/M state during MET. We show that in the absence of strong autocrine signals such as TGFβ (not included in this version), cells cannot maintain their mesenchymal state in the absence of mitogens, on softer matrices, or at high cell density. In contrast, potent autocrine signaling can stabilize the mesenchymal state in all but very dense monolayers on soft ECM. This expanded model also reproduces the inhibitory effects of TGFβ on proliferation and anoikis resistance in mesenchymal cells, as well as its ability to trigger apoptosis on soft ECM vs. EMT on stiff matrices. The model offers several experimentally testable predictions related to the effect of neighbors on partial vs. full EMT, the tug of war between mitosis and the maintenance of migratory hybrid E/M states, as well as cell cycle defects in dynamic, heterogeneous populations of epithelial, hybrid E/M and mesenchymal cells.
Project description:Abstract S. aureus is a major opportunistic pathogen infecting patients with diabetes. Increased mortality was observed following IV S. aureus infection in diabetic mice compared to non-diabetic controls, correlating with increased numbers of low density neutrophils (LDNs) and neutrophil extracellular traps (NETs). LDN development is dependent on TGFβ, which was more activated in the diabetic host. Neutralization of TGFβ, or the integrin responsible for its activation α5β8, reduced numbers of LDNs and improved survival. Comparison of high and low density neutrophils identified PTEN signaling as a central regulator of LDN NET release. Inhibition of PTEN improved survival and decreased NET production in infected diabetic mice. MEDI4893*, a monoclonal antibody that neutralizes alpha toxin (AT) in development for prevention of S. aureus infection, was able to block TGFβ activation, reduce LDNs and NETs, and significantly improve survival. Our data identify a population of neutrophils in infected diabetic mice which correlated with decreased survival and increased NET production. Targeting a single virulence factor of S. aureus prevented emergence of the LDN population and improved survival, supporting potential use of pathogen specific antibodies for treating diabetic infections.
Project description:Fringes are glycosyltransferases that transfer a GlcNAc to O-fucose residues on Epidermal Growth Factor-like (EGF) repeats. Three Fringes exist in mammals: LUNATIC FRINGE (LFNG), MANIC FRINGE (MFNG) and RADICAL FRINGE (RFNG). Fringe modification of O-fucose on EGF repeats in the NOTCH1 (N1) extracellular domain modulates the activation of N1 signaling. Not all O-fucose residues of N1 are modified by all Fringes; some are modified by one or two Fringes and others not modified at all. The distinct effects on N1 activity depend on which Fringe is expressed in a cell. However, little data is available on the effect that more than one Fringe has on the modification of O-fucose residues and the resulting downstream consequence on Notch activation. Using mass spectral glycoproteomic site mapping and cell-based N1 signaling assays, we compared the effect of co-expression of N1 with one or more Fringes on modification of O-fucose and activation of N1 in three cell lines. Individual expression of each Fringe with N1 in the three cell lines revealed differences in modulation of the Notch pathway dependent on the presence of endogenous Fringes. Despite these cell-based differences, co-expression of several Fringes with N1 demonstrated a dominant effect of LFNG over MFNG or RFNG. MFNG and RFNG appeared to be co-dominant but strongly dependent on the ligands used to activate N1 and on the endogenous expression of Fringes. These results show a hierarchy of Fringe activity and indicate that the effect of MFNG and/or RFNG could be small in the presence of LFNG.
Project description:The role of neutrophils in tumor is still controversial and largely unknown. We previously identified an anticancer tumor microenvironment from mice lacking Smad3, but the underlying mechanism is still largely unclear. Interestingly, depletion of neutrophils largely suppressed the anticancer phenotype of Smad3-KO mice against syngeneic murine Lewis lung carcinoma (LLC). Here, we discovered that Smad3 is essential for promoting N1/N2 polarization of the tumor_x0002_associated neutrophils (TANs) in lung carcinoma. We found that Smad3 deficiency dramatically increased N1 TANs associated with an anticancer phenotype in mice and detected a negative correlation between Smad3 activation and anticancer N1 associated with a higher mortality of NSCLC. By conducting a neutrophil-specific single-cell RNA-sequencing, we uncovered that Smad3 is essential for completing the N1/N2 polarization of TANs, whereas N1 will be the dominated phenotype in the Smad3-KO TME by analyzing the developmental pathways of TANs with pseudo-time at transcriptome level. Mechanistically, direct binding of Smad3 on the developmental genes in neutrophils under cancer condition was evidenced by ChIP-sequencing at genomic level. Importantly, both neutrophil-specific and pharmaceutical inhibition of Smad3 effectively enhanced the anticancer activity of human and murine TANs, thereby suppressing the progression of lung carcinoma in vivo. Thus, Smad3 may represent a precision therapeutic target for enhancing the anticancer activity of TANs via blocking N1/N2 polarization in NSCLC. in C57BL6 (wild-type) and Smad3-deficient (Smad3-/- ) mice and submitted for cell encapsulation and library construction by Chromium controller with 5’ expression kit (10x genomics)
Project description:Tumor infiltrating neutrophils (TAN) have been shown to exert both pro- and anti-tumoral activities and their recruitment and polarization are triggered by tumor-derived signals. Resident mesenchymal stromal cells (MSC) could contribute to tumor-supportive cell niche and have been shown to display tumor-specific transcriptomic, phenotypic, and functional features compared to normal tissue. In our study, we investigate whether these two cell subsets establish a bidirectional crosstalk in the context of B-cell lymphoma. We used microarrays to explore how neutrophils could trigger the polarization of tumor-supportive stromal cells. Gene expression analysis were performed on stromal cells (MSC) derived from bone marrow (BM) or tonsil (Resto) of healthy donors. These BM-MSC (n=3) or Resto (n=3) were primed or not with neutrophils for 1 day to induce stromal modification.
Project description:Neutrophils play a key role in the control of metastatic progression. Neutrophils are phenotypically heterogeneous and can exert either anti- or pro-metastatic functions. Here, we demonstrate that tumor cells capable of forming liver metastases induce an accumulation of neutrophils in the peripheral blood and liver parenchyma. Cancer cell-derived G-CSF, in concert with other factors, mobilizes immature low-density neutrophils that promote liver metastasis. In contrast, mature high-density neutrophils inhibit the formation of liver metastases. Transcriptomic and metabolomic analyses of high- and low- density neutrophils reveal engagement of numerous metabolic pathways specifically in low-density neutrophils. Low-density neutrophils exhibit enhanced global bioenergetic capacity, through their ability to engage mitochondrial-dependent ATP production, and remain capable of executing pro-metastatic neutrophil functions, including NETosis, under nutrient-deprived conditions. Together, these data reveal that distinct pro-metastatic neutrophil populations exhibit a high degree of metabolic flexibility, which facilitates metastatic progression and the formation of liver metastases.
Project description:Gene expression profiling for mouse N1 and N2 neutrophils. Neutrphils were isolated form the bone marrow of C57BL/6J mice between 12-16 weeks old. Approximately 8x10^7 neutrophils were used per condition and were split into 3 biological replicates. Freshly isolated neutrophils were cultured for 2h in RPMI medium, in the presence of 100 ng/ml lipopolysaccharide (LPS) and 20 ng/ml interferon gamma (IFNγ) or 20 ng/ml interleukin 4 (IL-4). Total RNA was isolated with TRIzol reagent and Phasemaker tubes. A sample from the LPS+IFNγ polarization did not pass the quality control test and was excluded from the downstream analysis.