Glioblastoma multiforme (GBM) are the most malignant and vascularized brain tumors. The aberrant vascular phenotype of GBM could be exploited for diagnosis or therapeutic targeting. This study identified new molecular markers of GBM vessels, using a combination of laser capture microdissection (LCM) microscopy, RNA amplification, and microarray analyses to compare vessels from nonmalignant human brain and GBM tumors. Forty-two genes were differentially expressed in GBM vessels compared to nonmalignant brain vessels. Validation of differentially expressed genes was performed by literature mining, Q-PCR, and immunohistochemistry. Among the differentially expressed genes, only 64% were previously associated with vessels, angiogenesis, gliomas, and/or cancer. The upregulation of genes encoding secreted extracellular proteins IGFBP7 and SPARC was confirmed by Q-PCR in LCM-captured vessels. Whereas SPARC and IGFBP7 protein were absent in nonmalignant brain vessels, a distinct immunoreactivity patterns were observed in GBM sections whereby SPARC was strongly expressed in perivascular cells adjacent to GBM vessels while GBM endothelial cells were immunostained for IGFBP7. IGFBP7 immunoreactivity was also detected on the abluminal side of GBM vessels deposited between strands of vascular basal lamina. The study discerns unique molecular characteristics of GBM vessels compared with nonmalignant brain vessels that could potentially be used for diagnostic or therapeutic purposes.
Although clinical variables are predictive of CAD events, CTA identified coronary atherosclerosis in a significant proportion of patients with low to intermediate FRS, and a small minority of patients with high FRS had no evidence of atherosclerosis. Prospective studies are required to determine the potential value of identifying coronary atherosclerosis using CTA and to assess whether modifying therapies based on these results are warranted.
Blood vessels in tumors frequently show abnormal characteristics, such as tortuous morphology or leakiness, but very little is known about protein expression in tumor vessels. In this study, we have used laser capture microdissection (LCM) to isolate microvessels from clinical samples of invasive ductal carcinoma (IDC), the most common form of malignant breast cancer, and from patient-matched adjacent nonmalignant tissue. This approach eliminates many of the problems associated with the heterogeneity of clinical tumor tissues by controlling for differences in protein expression between both individual patients and different cell types. Proteins from the microvessels were trypsinized and the resulting peptides were quantified by a labelfree nanoLCÀMS method. A total of 86 proteins were identified that are overexpressed in tumor vessels relative to vessels isolated from the adjacent nonmalignant tissue. These proteins include well-known breast tumor markers such as Periostin and Tenascin C but also proteins with lesser-known or emerging roles in breast cancer and tumor angiogenesis (i.e., Serpin H1, Clic-1, and Transgelin 2). We also identified 40 proteins that were relatively under-expressed in IDC tumor vessels, including several components of the basement membrane whose lower expression could be responsible for weakening tumor vessels. Lastly, we show that a subset of 29 proteins, derived from our list of differentially expressed proteins, is able to predict survival in three publicly available clinical breast cancer microarray data sets, which suggests that this subset of proteins likely plays a functional role in cancer progression and outcome.
Site-directed mutagenesis was used to map the ligandbinding surface of the type II transforming growth factor-L L receptor extracellular domain (TL LRII-ECD). Two putative ligand-binding sites were probed, the first being a predicted hydrophobic patch, the second being the finger 1 surface loop. Nine residues were mutated in the context of full-length TL LRII and the effect of these mutations on ligand-binding and receptor signaling was analyzed. Complementary information was obtained by examining`natural' evolutionary TL LRII mutations. Together, the results indicate that residues within the finger 1 region, but not the hydrophobic patch, of the TL LRII-ECD are required for productive ligand-binding. We conclude that, surprisingly, the ECDs of TL LRII and type II activin receptor utilize distinct interacting surfaces for binding their respective ligands. ß
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