The brain is a common site of metastatic disease in patients with breast cancer, which has few therapeutic options and dismal outcomes. The purpose of our study was to identify common and rare events that underlie breast cancer brain 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 brain metastasis cohort. While overall methylation levels were increased in breast cancer brain metastasis, basal-like brain 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 brain metastasis has provided insight into the somatic events underlying this disease, which have potential in forming the basis of future therapeutic strategies.
Brain metastasis (BM) can affect ? 25% of nonsmall cell lung cancer (NSCLC) patients during their lifetime. Efforts to characterize patients that will develop BM have been disappointing. microRNAs (miRNAs) regulate the expression of target mRNAs. miRNAs play a role in regulating a variety of targets and, consequently, multiple pathways, which make them a powerful tool for early detection of disease, risk assessment, and prognosis. We investigated miRNAs that may serve as biomarkers to differentiate between NSCLC patients with and without BM. miRNA microarray profiling was performed on samples from clinically matched NSCLC from seven patients with BM (BM+) and six without BM (BM-). Using t-test and further qRT-PCR validation, eight miRNAs were confirmed to be significantly differentially expressed. Of these, expression of miR-328 and miR-330-3p were able to correctly classify BM+ vs. BM- patients. This classifier was used on a validation cohort (n = 15), and it correctly classified 12/15 patients. Gene expression analysis comparing A549 parental and A549 cells stably transfected to over-express miR-328 (A549-328) identified several significantly differentially expressed genes. PRKCA was one of the genes over-expressed in A549-328 cells. Additionally, A549-328 cells had significantly increased cell migration compared to A549 cells, which was significantly reduced upon PRKCA knockdown. In summary, miR-328 has a role in conferring migratory potential to NSCLC cells working in part through PRKCA and with further corroboration in additional independent cohorts, these miRNAs may be incorporated into clinical treatment decision making to stratify NSCLC patients at higher risk for developing BM.
The s allele serotonin transporter polymorphic region (5-HTTLPR) is associated with a number of physiological mechanisms that may increase the risk of elevated depressive symptoms. However, reports of a relationship between serotonin transporter polymorphic region (5-HTTLPR) genotype and depressive symptoms have thus far been inconclusive. This heterogeneity of results suggests that other factors may be moderating the relationship between 5-HTTLPR and depressive symptoms. Higher levels of physical activity are associated with lower levels of depressive symptoms. Mechanisms responsible for this association include alterations of the serotonergic system and the hypothalamic-pituitary axis. The aim of the current study was to measure the moderating effect of physical activity on the relationship between 5-HTTLPR genotype and depressive symptoms. Participants, ages 18-23, provided a saliva sample for DNA analysis and completed questionnaires to assess depressive symptoms and physical activity. A hierarchical multiple regression analysis was conducted to examine the moderating effect of physical activity on the relationship between 5-HTTLPR genotype and depressive symptoms. Analysis revealed a significant interaction between 5-HTTLPR and physical activity (p = .010). At low levels of physical activity, individuals with at least one s allele had significantly higher levels of depressive symptoms compared to ll individuals (p = .011). This finding provides preliminary support for a moderating effect of physical activity on the relationship between 5-HTTLPR and depressive symptoms.
The ability to selectively detect and target cancer cells that have undergone an epithelial-mesenchymal transition (EMT) may lead to improved methods to treat cancers such as pancreatic cancer. The remodeling of cellular glycosylation previously has been associated with cell differentiation and may represent a valuable class of molecular targets for EMT.
Exercise is effective in the alleviation of depressive symptoms and may have physiological effects similar to those of selective serotonin reuptake inhibitors (SSRI). Recent research has identified the difference in treatment effects across genetic polymorphisms of the serotonin transporter polymorphic region (5-HTTLPR), in which the l allele has been associated with a better response to SSRI compared with the s allele. The purpose of the current research was to examine the antidepressant effects of exercise across 5-HTTLPR genotypes.
Glioblastoma (GB) is the most common and lethal type of primary brain tumor. Clinical outcome remains poor and is essentially palliative due to the highly invasive nature of the disease. A more thorough understanding of the molecular mechanisms that drive glioma invasion is required to limit dispersion of malignant glioma cells.
Malignant glioblastomas are characterized by their ability to infiltrate into normal brain. We previously reported that binding of the multifunctional cytokine TNF-like weak inducer of apoptosis (TWEAK) to its receptor fibroblast growth factor-inducible 14 (Fn14) induces glioblastoma cell invasion via Rac1 activation. Here, we show that Cdc42 plays an essential role in Fn14-mediated activation of Rac1. TWEAK-treated glioma cells display an increased activation of Cdc42, and depletion of Cdc42 using siRNA abolishes TWEAK-induced Rac1 activation and abrogates glioma cell migration and invasion. In contrast, Rac1 depletion does not affect Cdc42 activation by Fn14, showing that Cdc42 mediates TWEAK-stimulated Rac1 activation. Furthermore, we identified two guanine nucleotide exchange factors (GEF), Ect2 and Trio, involved in TWEAK-induced activation of Cdc42 and Rac1, respectively. Depletion of Ect2 abrogates both TWEAK-induced Cdc42 and Rac1 activation, as well as subsequent TWEAK-Fn14-directed glioma cell migration and invasion. In contrast, Trio depletion inhibits TWEAK-induced Rac1 activation but not TWEAK-induced Cdc42 activation. Finally, inappropriate expression of Fn14 or Ect2 in mouse astrocytes in vivo using an RCAS vector system for glial-specific gene transfer in G-tva transgenic mice induces astrocyte migration within the brain, corroborating the in vitro importance of the TWEAK-Fn14 signaling cascade in glioblastoma invasion. Our results suggest that the TWEAK-Fn14 signaling axis stimulates glioma cell migration and invasion through two GEF-GTPase signaling units, Ect2-Cdc42 and Trio-Rac1. Components of the Fn14-Rho GEF-Rho GTPase signaling pathway present innovative drug targets for glioma therapy.
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