Project description:Epithelial-to-mesenchymal transition (EMT) plays a crucial role in metastasis, which is the leading cause of death in breast cancer patients. We show that Cdc42 GTPase-activating protein (CdGAP) promotes tumor formation and metastasis to lungs in the HER2-positive (HER2+) murine breast cancer model. CdGAP facilitates intravasation, extravasation, and growth at metastatic sites. CdGAP depletion in HER2+ murine primary tumors mediates crosstalk with a Dlc1-RhoA pathway and is associated with a transforming growth factor-β (TGF-β)-induced EMT transcriptional signature. To further delineate the molecular mechanisms underlying the pro-migratory role of CdGAP in breast cancer cells, we searched for CdGAP interactors by performing a proteomic analysis using HEK293 cells overexpressing GFP-CdGAP. We found that CdGAP interacts with the adaptor Talin to modulate focal adhesion dynamics and integrin activation. Moreover, HER2+ breast cancer patients with high CdGAP mRNA expression combined with a high TGF-β-EMT signature are more likely to present lymph node invasion. Our results suggest CdGAP as a candidate therapeutic target for HER2+ metastatic breast cancer by inhibiting TGF-β and Integrin/Talin signaling pathways.
Project description:CdGAP/ARHGAP31 is a molecular target of TGFb-mediated EMT and required for Her2-positive breast cancer growth and metastasis Metastasis is the leading cause of death in breast cancer patients. The epithelial-to-mesenchymal transition (EMT) has a crucial role in metastasis and is highly critical for tumor cell dissemination. CdGAP/ARHGAP31 is highly expressed in breast cancer tissues and is associated with poor clinical outcome in breast cancer patients. CdGAP cooperates in a GAP-independent manner with the transcriptional repressor Zeb2 to function as a critical modulator of breast cancer through repression of E-cadherin transcription. In this study, we used a murine model of Her2+ breast cancer to investigate further the role of CdGAP in breast tumorigenesis. We found that CdGAP was essential for tumor formation and metastasis to the lungs in the Her2+ mouse breast cancer model. We determined that CdGAP is required for intravasation and growth at the metastatic sites. By using global gene expression approaches, we found that CdGAP depletion in Her2+ primary tumors was associated with an EMT signature, including a decreased expression of the metastatic factor claudin-2 and an increase in E-cadherin expression. In Her2+ breast cancer cells, CdGAP expression is positively regulated by the TGFb canonical pathway in a smad-dependent manner and regulates cell proliferation, migration, invasion, and adhesion. CdGAP was found to interact with the focal adhesion protein Talin and regulates focal adhesion dynamics in breast cancer cells. Collectively, CdGAP appears as a potential anti-metastatic target for the treatment of Her2+ breast cancer.
Project description:The lungs are a frequent target of metastatic breast cancer cells, but the underlying molecular mechanisms are unclear. All existing data were obtained either using statistical association between gene expression measurements found in primary tumors and clinical outcome, or using experimentally derived signatures from mouse tumor models. Here, we describe a distinct approach that consists to utilize tissue surgically resected from lung metastatic lesions and compare their gene expression profiles with those from non-pulmonary sites, all coming from breast cancer patients. We demonstrate that the gene expression profiles of organ-specific metastatic lesions can be used to predict lung metastasis in breast cancer. We identified a set of 21 lung metastasis-associated genes. Using a cohort of 72 lymph node-negative breast cancer patients, we developed a six-gene prognostic classifier that discriminated breast primary cancers with a significantly higher risk of lung metastasis. We then validated the predictive ability of the six-gene signature in 3 independent cohorts of breast cancers consisting of a total of 721 patients. Finally, we demonstrated that the signature improves risk stratification independently of known standard clinical parameters and a previously established lung metastasis signature based on an experimental breast cancer metastasis model. Experiment Overall Design: We used microarrays to identify lung metastasis-related genes in a series of 23 patients with breast cancer metastases. No replicate, no reference sample.
Project description:To define the molecular regulators of metastasis of triple-negative breast cancer, we conducted a rigorous characterization of four populations of MDA-MB-231 human triple-negative breast cancer cells that display a range of intrinsic spontaneous metastatic capacities in immuno-deficient mice, from non-metastatic to highly metastatic to lung, liver, spleen and spine. PAT-Seq gene expression profiling of primary tumor cells identified the fibroblast growth factor homologous factor, FGF13, as a candidate metastatic virulence gene highly upregulated in aggressively metastatic MDA-MB-231HM tumors.
Project description:This SuperSeries is composed of the following subset Series: GSE23904: Gene expression profilling of poorly metastatic MDA cells and highly metastatic LM2 cells. GSE23905: miR-126 over-expression in highly metastatic LM2 breast cancer cells. Refer to individual Series
Project description:To define the molecular regulators of metastasis of triple-negative breast cancer, we conducted a rigorous characterization of four isogenic populations of MDA-MB-231 human triple-negative breast cancer cells that display a range of intrinsic spontaneous metastatic capacities in immuno-deficient mice, from non-metastatic to highly metastatic to lung, liver, spleen and spine. PAT-Seq gene expression profiling of primary tumor cells identified the fibroblast growth factor homologous factor, FGF13, as a candidate metastatic virulence gene highly upregulated in aggressively metastatic MDA-MB-231HM tumors.