Project description:The goal of this study is to determine the extracellular miRNAs associated with breast cancer metastasis to the brain. By combining the small RNA-seq data of patient sera and cell culture models, we are able to select breast cancer cell-derived miRNAs that are associated with brain metastasis for further functional study.
Project description:Brain metastasis is one of the most feared complications of cancer and the most common intracranial malignancy in adults. Its underlying mechanisms remain unknown. From breast cancer patients with metastatic disease we isolated cell populations that aggressively colonize the brain. Transcriptomic analysis of these cells yielded overlapping gene sets whose expression is selectively associated with brain metastasis. The expression of seventeen of these genes in primary breast tumors is associated with brain relapse in breast cancer patients. Some of these genes are also associated with metastasis to lung but not to liver, bone or lymph nodes, providing a molecular basis for the long-observed clinical link between brain and lung metastasis. Among the functionally validated brain metastasis genes, the cyclooxygenase COX-2, the EGFR ligand HB-EGF, and the brain-specific α2-6 sialyltransferase ST6GALNAC5 mediate cancer cell passage through the blood-brain barrier. Other brain metastasis genes encode inflammatory factors and brain-specific proteolytic regulators, suggesting a multifaceted program for breast cancer colonization of the brain.
Project description:The central nervous system (CNS) is a common site of metastatic disease in patients with breast cancer and has few therapeutic options with dismal outcomes. The purpose of our study was to identify common and rare events that underlie breast cancer CNS metastasis. We performed deep genomic profiling, which integrated gene copy number, gene expression and DNA methylation datasets on a collection of breast brain metastases. We identified frequent large chromosomal gains in 1q, 5p, 8q, 11q, and 20q and frequent broad level deletions involving 8p, 17p, 21p and Xq. Frequently amplified and overexpressed genes included ATAD2, BRAF, DERL1, DNMTRB and NEK2A. The ATM, CRYAB and HSPB2 genes were commonly deleted and underexpressed. Knowledge mining revealed enrichment in cell cycle and G2/M transition pathways, which contained AURKA, AURKB and FOXM1. Using the PAM50 breast cancer intrinsic classifier, Luminal B, Her2+/ER negative, and basal-like tumors were identified as the most commonly represented breast cancer subtypes in our CNS metastasis cohort. While overall methylation levels were increased in breast cancer CNS metastasis, basal-like CNS metastases were associated with significantly lower levels of methylation. Integrating DNA methylation data with gene expression revealed defects in cell migration and adhesion due to hypermethylation and downregulation of PENK, EDN3, and ITGAM. Hypomethylation and upregulation of KRT8 likely affects adhesion and permeability. Genomic and epigenomic profiling of breast CNS metastasis has provided insight into the somatic events underlying this disease, which have potential in forming the basis of future therapeutic strategies. Three sample-types: 35 Breast Brain Metastasis samples, 10 Non-Neoplastic Brain samples, and 10 Non-Neoplastic Breast samples.
Project description:Brain metastasis is one of the most feared complications of cancer and the most common intracranial malignancy in adults. Its underlying mechanisms remain unknown. From breast cancer patients with metastatic disease we isolated cell populations that aggressively colonize the brain. Transcriptomic analysis of these cells yielded overlapping gene sets whose expression is selectively associated with brain metastasis. The expression of seventeen of these genes in primary breast tumors is associated with brain relapse in breast cancer patients. Some of these genes are also associated with metastasis to lung but not to liver, bone or lymph nodes, providing a molecular basis for the long-observed clinical link between brain and lung metastasis. Among the functionally validated brain metastasis genes, the cyclooxygenase COX-2, the EGFR ligand HB-EGF, and the brain-specific α2-6 sialyltransferase ST6GALNAC5 mediate cancer cell passage through the blood-brain barrier. Other brain metastasis genes encode inflammatory factors and brain-specific proteolytic regulators, suggesting a multifaceted program for breast cancer colonization of the brain. Experiment Overall Design: Two different breast cancer cell lines, MDA-MB-231 and freshly isolated pleural effusion CN34 were used in this study. The MDA-MB-231 group contains three biological replicates of the parental, unselected population, and 4 brain metastatic isolates. CN34 contains 2 biological replicates of the parental, unselected population, and 4 brain metastatic isolates. In each case, the parental population was compared to the brain metastatic isolates to identify gene expression changes associated with the brain metastatic phenotype.
Project description:Breast cancer is the leading type of cancer in women. Breast cancer brain metastasis is considered as an essential issue in breast cancer patients. Membrane proteins play important roles in breast cancer brain metastasis that contributes to the cell adhesion and penetration of blood-brain barrier. To achieve a deeper insight of the mechanism of breast cancer brain metastasis, liquid chromatography tandem mass spectrometry (LC-MS/MS) was performed to analyze the enriched membrane proteomes from six different breast cancer cell lines. Quantitative proteomic data of all cell lines were compared with MDA-MB-231BR which has the specific brain metastasis capacity. 1239 proteins were identified and 990 were quantified with more than 70% of membrane proteins in all cell lines. Each cell line can be separated apart from others in PCA. Ingenuity pathway analysis (IPA) supported the high brain metastatic ability of 231BR and suggested importance of the up-regulation of integrin proteins and down-regulation of EPHA in brain metastasis. 28 proteins were observed unique expression alteration in 231BR. The up-regulation of NPM1, hnRNP Q, hnRNP K and eIF3l and the down-regulation of TUBB4B and TUBB were observed to be associated with the brain metastasis cell line and may contributes to the breast cancer brain metastasis.
Project description:Brain metastasis is a major cause of cancer mortality, but its molecular mechanisms are severely understudied. We found that YTHDF3 overexpression clinically correlates with brain metastases in breast cancer patients and is required for brain metastasis. Silencing YTHDF3 suppressed the brain metastasis of breast cancer cells in vitro and in vivo. Integrated transcriptome and m6A-seq analysis revealed alter expression of selected YTHDF3 target genes, including ST6GALNAC5, GJA1, and EGFR by promoting m6A-dependent translation of these target transcripts. Our work uncovers an essential role of YTHDF3 in controlling the interaction between cancer cells and brain microenvironment, thereby gaining brain metastatic competence.
Project description:Brain metastasis is a major cause of cancer mortality, but its molecular mechanisms are severely understudied. We found that YTHDF3 overexpression clinically correlates with brain metastases in breast cancer patients and is required for brain metastasis. Silencing YTHDF3 suppressed the brain metastasis of breast cancer cells in vitro and in vivo. Integrated transcriptome and m6A-seq analysis revealed alter expression of selected YTHDF3 target genes, including ST6GALNAC5, GJA1, and EGFR by promoting m6A-dependent translation of these target transcripts. Our work uncovers an essential role of YTHDF3 in controlling the interaction between cancer cells and brain microenvironment, thereby gaining brain metastatic competence.
Project description:We hypothesized that circulating miRNAs could work as biomarkers for early detection of breast cancer brain metastasis (BCBM), and their targets could constitute new targets for modulation. We used a mouse model of BCBM and Next-Generation Sequencing to establish the circulating miRNAs alterations along brain metastasis development and performed bioinformatics analysis to identify their targets with relevance in the metastatic process. We additionally analyzed human resected brain metastasis of breast cancer patients for target’s expression validation. In our mouse model, we observed a deregulation of circulating miRNAs profile during BCBM progression, with a downregulation of miR-802-5p and miR-194-5p in plasma prior to brain metastases detection. The transcription factor myocyte enhancer factor 2C (MEF2C), was identified as a target for both miRNAs, and its expression was increasingly observed in malignant cells along brain metastasis development. Its upregulation was also observed in peritumoral astrocytes and in human BCBM. Collectively, downregulation of circulating miR-802-5p and miR-194-5p appear as precocious biomarkers for BCBM and MEF2C emerges as a new player and a potential target for modulation.