Project description:Murine 4T1-T breast cancer cells were infected with an shRNA targeting Asparagine Synthetase (Asns) and grown in DMEM +/- asparagine. Cells were harvested and processed with the NuGen Ovation RNAseq system V2. Libraries were sequenced on an Illumina platform and mapped using Bowtie2 to the mm10 genome prior to transcript quantification using HT-Count.
Project description:Using a functional model of breast cancer heterogeneity, we previously showed that clonal sub-populations proficient at generating circulating tumour cells were not all equally capable of forming metastases at secondary sites1. A combination of differential expression and focused in vitro and in vivo RNAi screens revealed candidate drivers of metastasis that discriminated metastatic clones. Among these, Asparagine Synthetase (ASNS) expression in a patient’s primary tumour was most strongly correlated with later metastatic relapse. Here, we have shown that asparagine bioavailability strongly influences metastatic potential. Limiting asparagine by Asns knockdown, treatment with L-asparaginase, or dietary asparagine restriction reduced metastasis without impacting growth of the primary tumour, whereas increased dietary asparagine or enforced Asns expression promoted metastatic progression. Altering asparagine availability in vitro strongly influenced invasive potential, and this was correlated with an impact on proteins that promote the epithelial to mesenchymal transition. This provides at least one potential mechanism for how the bioavailability of a single amino acid could regulate metastatic progression.
Project description:Germinal centre (GC) B cells proliferate at some of the highest rates of any mammalian cell. Yet the metabolic processes which enable this are poorly understood. We performed integrated metabolomic and transcriptomic profiling of GC B cells, and found that asparagine metabolism is highly upregulated. Asparagine is conditionally essential to B cells, and its synthetic enzyme, asparagine synthetase (ASNS) is markedly upregulated following their activation, through the integrated stress response sensor general control non-derepressible 2 (GCN2). When Asns is deleted, B cell survival in low asparagine conditions is severely impaired. Using stable isotope tracing, we found that metabolic adaptation to the absence of asparagine requires ASNS, and that the synthesis of nucleotides is particularly sensitive to asparagine deprivation. Conditional deletion of Asns in B cells selectively impairs GC formation, associated with a reduction in RNA synthesis rates. Finally, removal of environmental asparagine by asparaginase was found to also severely compromise the GC reaction.
Project description:Molecular comparison between control 4T1 cells with MMP3-low 4T1 cells RNA extracted from biological triplicates of each of the above mentioned cell populations were subjected to microarray analysis
Project description:In this project, 4T1 parental cells (4T1/WT) were exposed to increasing concentrations of epirubicin (EPB) to establish a novel multi-drug resistant CSC-like breast cancer cell line (4T1/EPB). The ubiquitinated proteins were enriched from 4T1/WT or 4T1/EPB derived cell lysate using a-Al2O3-Vx3 nanoparticles to produce the covalently linked product UPs nanovaccine. Label-free LC-MS/MS mass spectrometry was used to detect the type and amount of enriched proteins of UPs from the 4T1/WT cells and the 4T1/EPB cells.
Project description:Novel therapies targeting cancer stem cells (CSCs), which play critical roles in chemo- and radio-resistance, metastasis, and possibly resistance against cancer immunotherapy including granulocyte-macrophage colony-stimulating factor (GM-CSF) gene-transduced tumor cell vaccines, may provide beneficial clinical outcomes. Here, we used syngeneic immunocompetent mice that allowed precise evaluation of the immunogenicity of the side population (SP) isolated from 4T1 murine breast carcinoma (4T1-SP) cells as putative CSCs. 4T1-SP cells showed various stem cell properties including high capacities for colony formation and tumorigenicity as well as high expression of phosphorylated signal transducer and activator of transcription-3 and vascular endothelial growth factor that are inductive of immune tolerance. Despite these progressive malignant characteristics of 4T1-SP cells, subcutaneous injection of non-transmissible Sendai virus-mediated GM-CSF gene-transduced 4T1-SP (4T1-SP/GM) cells remarkably impaired their tumorigenicity compared with that of the controls. This impairment of tumorigenicity was partially dependent on CD8+ T cells in concert with CD4+ T cells and natural killer cells. Notably, therapeutic vaccinations using irradiated 4T1-SP/GM cells markedly suppressed tumor development of subcutaneously transplanted 4T1-SP cells compared with that of the controls including irradiated 4T1-non-SP/GM cells. Tumor suppression was accompanied by robust accumulation of mature dendritic cells at vaccination sites and systemic Th1-based cellular immunity. Moreover, vaccinations comprising primary 4T1-SP cells isolated from transplanted 4T1-SP tumors elicited antitumor effects. cDNA microarray analysis showed that 4T1-SP cells predominantly expressed genes of cancer-related antigens including cancer/testis antigens. Collectively, we demonstrate that SP cell-based vaccinations induce effective antitumor immunity that may improve the efficacy of SP cell-based immunotherapy. Gene expression profiles were compared between sorted 4T1-SP and 4T1-NSP cells.