Biological and Molecular Heterogeneity of Breast Cancers Correlates with Their Cancer Stem Cell Content

SummaryPathways that govern stem cell (SC) function are often subverted in cancer. Here, we report the isolation to near purity of human normal mammary SCs (hNMSCs), from cultured mammospheres, on the basis of their ability to retain the lipophilic dye PKH26 as a consequence of their quiescent nature. PKH26-positive cells possess all the characteristics of hNMSCs. The transcriptional profile of PKH26-positive cells (hNMSC signature) was able to predict biological and molecular features of breast cancers. By using markers of the hNMSC signature, we prospectively isolated SCs from the normal gland and from breast tumors. Poorly differentiated (G3) cancers displayed higher content of prospectively isolated cancer SCs (CSCs) than did well-differentiated (G1) cancers. By comparing G3 and G1 tumors in xenotransplantation experiments, we directly demonstrated that G3s are enriched in CSCs. Our data support the notion that the heterogeneous phenotypical and molecular traits of human breast cancers are a function of their CSC content

Relationships between EGFR Signaling–competent and Endocytosis-competent Membrane Microdomains

Membrane microdomains, the so-called lipid rafts, function as platforms to concentrate receptors and assemble the signal transduction machinery. Internalization, in most cases, is carried out by different specialized structures, the clathrin-coated pits. Here, we show that several endocytic proteins are efficiently recruited to morphologically identified plasma membrane lipid rafts, upon activation of the epidermal growth factor (EGF) receptor (EGFR), a receptor tyrosine kinase. Analysis of detergent-resistant membrane fractions revealed that the EGF-dependent association of endocytic proteins with rafts is as efficient as that of signaling effector molecules, such as Grb2 or Shc. Finally, the EGFR, but not the nonsignaling transferrin receptor, could be localized in nascent coated pits that almost invariably contained raft membranes. Thus, specialized membrane microdomains have the ability to assemble both the molecular machineries necessary for intracellular propagation of EGFR effector signals and for receptor internalization

Alternative Erasing Times Of The Denoptix System Plate: Performance On The Detection Of Proximal Caries.

Our aim was to investigate the DenOptix system for detection of proximal caries using alternative erasing times for the photostimulable phosphor plates. Human teeth were X-rayed with phosphor plates using different erasing times. Five observers evaluated the images for the presence of caries by scoring the proximal surfaces of each tooth. Mean pixel intensity analyses were also carried out. The erasing times were evaluated using receiver operating characteristic (ROC) curve analysis. Analysis of variance for differences among erasing times and pixel intensity values was performed, followed by linear regression analysis for correlation between these variables. The mean ROC curve for each erasing time varied from 0.61 to 0.66 (not significant). Analysis of variance did not show any significant effect of the erasing times on the pixel intensity values of the images (P > .05). Erasing times for DenOptix phosphor plates from 20 to 130 s were satisfactory for diagnosis of proximal caries, and their use is therefore feasible in clinical practice.107122-

TTP specifically regulates the internalization of the transferrin receptor.

SummaryDifferent plasma membrane receptors are internalized through saturable/noncompetitive pathways, suggesting cargo-specific regulation. Here, we report that TTP (SH3BP4), a SH3-containing protein, specifically regulates the internalization of the transferrin receptor (TfR). TTP interacts with endocytic proteins, including clathrin, dynamin, and the TfR, and localizes selectively to TfR-containing coated-pits (CCP) and -vesicles (CCV). Overexpression of TTP specifically inhibits TfR internalization, and causes the formation of morphologically aberrant CCP, which are probably fission impaired. This effect is mediated by the SH3 of TTP, which can bind to dynamin, and it is rescued by overexpression of dynamin. Functional ablation of TTP causes a reduction in TfR internalization, and reduced cargo loading and size of TfR-CCV. Tyrosine phosphorylation of either TTP or dynamin prevents their interaction, pointing to a possible mechanism of exclusion of TTP from some CCP. Thus, TTP might represent one of the long sought for molecules that allow cargo-specific control of clathrin endocytosis

The effect of re-operation on survival in patients with recurrent glioblastoma

Treatment options for glioblastoma (GBM) at recurrence have limited efficacy. Re-surgery has been used for confirmation of recurrent disease and to provide relief of symptoms but the real impact on survival is unknown. PATIENTS AND METHODS: A retrospective analysis was performed for GBM patients followed between 01/2005 and 06/2010 at our Institution. RESULTS: Two hundred and thirty-two patients with recurrent GBM were evaluated. One hundred and two patients (44%) were treated with re-surgery followed by chemotherapy and 130 patients (56%) with chemotherapy alone. In multivariate analysis, no significant effect of re-surgery was found, with age (p=0.001), MGMT methylation (p=0.002) and PFS at 6 months (p=0.0001) being significant prognostic factors. CONCLUSION: Second surgery might have a limited impact in the clinical course of recurrent GBM patients