Project description:IL13Rα2 overexpression promotes metastasis of basal-like breast cancers IL13Rα2 depletion in highly metastatic breast cancer cells suppresses lung metastases formation by upregulating TP63 and decreasing their migratory potential
Project description:Lung metastasis is the principal cause of breast cancer-related mortality. Neutrophils have emerged as an important component of the tumor microenvironment (TME), supporting tumor proliferation and mediating immunosuppression. Here, we show that aconitate decarboxylase 1 (Acod1) is highly expressed in tumor-infiltrating neutrophils and promotes breast cancer lung metastasis by supporting neutrophil survival in the TME. Acod1 expression is regulated by tumor-derived granulocyte-macrophage colony-stimulating factor (GM-CSF) through the JAK/STAT signaling pathway and CCAAT/enhancer-binding protein beta (C/EBPβ) transcription factor activity. Acod1 loss in tumor-infiltrating neutrophils leads to ferroptosis-like cell death, resulting in decreased frequency of neutrophils in the TME. Mechanistically, itaconate, the product of Acod1, activates nuclear factor erythroid 2-related factor 2 (Nrf2), resulting in upregulated antioxidant responses and decreased lipid-reactive oxygen species. Genetical deletion of Acod1 in neutrophils suppresses lung metastasis of breast cancer in mouse models by decreasing neutrophil-lymphocyte ratio and elevating cytotoxic T cell response. Importantly, genetic targeting of Acod1 enhances the anti-tumor efficacy of immune checkpoint blockade. Overall, our findings reveal a mechanism of how immunosuppressive neutrophils survive in the harsh TME and support Acod1-targeting approaches for cancer treatment.
Project description:A novel RCAS-Cre-IRES-PyMT (RCI-PyMT) virus was designed to specifically knockout genes of interest in tumors generated in appropriate mutant mouse hosts. We used this tumor knockout, or TuKO, strategy to concisely ablate fgfr1 in PyMT induced mammary tumors in K19-tva/fgfr1loxP/loxP mice. The similarly injected control K19-tva mice developed mammary tumors exhibiting high metastasis penetration to lung, making this an ideal model for breast cancer metastasis. The fgfr1 TuKO tumors showed significantly decreased primary tumor growth, and most importantly, greatly reduced metastasis to lung. Our study suggests that FGFR1 signaling is a key pathway driving breast cancer lung metastasis and that targeting FGFR1 in breast cancer is an exciting approach to inhibit metastasis.
Project description:IL13R?2 overexpression promotes metastasis of basal-like breast cancers IL13R?2 depletion in highly metastatic breast cancer cells suppresses lung metastases formation by upregulating TP63 and decreasing their migratory potential MCF10CA1a (MIV) cells expressing the luciferase gene (MIV-Luc), were stably transduced with lentiviral constructs expressing either scrambled shRNA or shRNA against IL13R?2. The two cell lines were then either mock treated or treated with 20ng/ml IL13 for 16h followed by RNA isolation. Gene expression analysis was performed using the Affymetrix Human Exon 1.0 ST platform. Array data was processed by Affymetrix Exon Array Computational Tool.
Project description:To determine the roles of RBP2 in breast cancer metastasis, MDA-MD-231 cells were transfected with siRNAs against RBP2 or luciferase control, followed with gene expression microarray analysis and gene set enrichment analysis. These analyses revealed that RBP2 knockdown significantly decreased expression of genes linked to breast cancer metastasis to lung. Total RNA obtained from the breast cancer cell line MDA-MB231 72 hours after transfection with siRNA targeting KDM5A/RBP2/JARID1A, and targeting Luceferase gene as a control.
Project description:Estrogen receptor (ER)-positive luminal breast cancer is a subtype with generally lower risk of metastasis to most distant organs. However, bone recurrence occurs preferentially in luminal cancer. The mechanisms of the subtype-specific organotropism remain elusive. Here we show that an ER-regulated secretory protein SCUBE2 contributes to bone tropism of luminal breast cancer. Single-cell RNA sequencing analysis reveals osteoblastic enrichment by SCUBE2 in early bone-metastatic niches. SCUBE2 facilitates release of tumor membrane-anchored SHH to activate Hedgehog signaling in mesenchymal stem cells, thus promoting osteoblast differentiation. Osteoblasts deposit collagens to suppress NK cells via the inhibitory LAIR1 signaling and promote tumor colonization. SCUBE2 expression and secretion are associated with osteoblast differentiation and bone metastasis in human tumors. Targeting Hedgehog by Sonidegib and targeting SCUBE2 with a neutralizing antibody both effectively suppress bone metastasis in multiple metastasis models. Overall, our findings provides an explanation for bone preference in luminal breast cancer and new approaches for metastasis treatment.
Project description:The existence of breast cancer stem cells (BCSCs) is a major reason underlying cancer metastasis and recurrence after chemotherapy and radiotherapy. Targeting BCSCs may ameliorate breast cancer relapse and therapy resistance. Here, we report that expression of the pseudokinase Tribble 3 (TRIB3) positively associates with breast cancer stemness and progression. Elevated TRIB3 expression supports BCSCs by interacting with AKT to interfere with the FOXO1-AKT interaction and suppress FOXO1 phosphorylation, ubiquitination, and degradation by E3 ligases SKP2 and NEDD4L. The accumulated FOXO1 promotes transcriptional expression of SOX2, a transcriptional factor for cancer stemness, which in turn, activates FOXO1 transcription and forms a positive regulatory loop. Disturbing the TRIB3-AKT interaction suppresses BCSCs by accelerating FOXO1 degradation and reducing SOX2 expression in mouse models of breast cancer. Our study provides insights into breast cancer development and confers a potential therapeutic strategy against TRIB3-overexpressed breast cancer.
Project description:The skeleton is the most common metastasis site of breast cancer cells and the molecular underpinning of this process is incompletely understood. The tumor suppressor gene deleted in liver cancer-1 (DLC1) encodes a multi-domain protein including a RhoGTPase activating protein (RhoGAP) domain and has been reported to suppress the lung colonization of breast cancer cells. However, the role of DLC1 in breast cancer bone metastasis and the importance of RhoGAP-dependent and -independent pathways in this process remain unclear. Here, we showed that DLC1 silencing is linked to enhanced bone-tropism of breast cancer cell lines and poor prognosis of clinical samples. In the study presented here, DLC1 was overexpressed in the SCP2 breast cancer cells, and the control SCP2 and overexpression cells were treated with TGFbeta. Microarray profiling of mRNA levels was performed in the control and overexpression cells with or without TGFbeta treatment.
Project description:Metastasis is a major factor responsible for mortality in breast cancer patients. Id1 plays important roles in cell differentiation and promotes tumor angiogenesis, cell invasion and metastasis. Although Id1 is established as a critical factor for lung metastasis in breast cancer, the pathways and molecular mechanisms of Id1 functions in metastasis remains to be defined. Here we show that Id1 interacts with TFAP2A to suppress S100A9 expression. The expression of Id1 and S100A9 is inversely correlated in both breast cancer cell lines and clinical samples. We also find that S100A9 expression rescues the migratory and invasive phenotypes in vitro and metastasis in vivo induced by Id1 expression. S100A9 also suppresses the expression of known metastasis promoting factor RhoC activated by Id1 expression. Our results suggest that S100A9 mediates the functions of Id1 in breast cancer metastasis.