Citations

Abstract Purpose: Glioblastoma multiforme (GBM) is a devastating disease. Recent studies suggest that the stem cell properties of GBM contribute to the development of therapy resistance. Experimental Design: The expression of Survivin and Ran was evaluated by immunohistochemistry with GBM tissues, and quantitative reverse transcriptase (qRT)-PCR and immunocytochemistry with patient-derived GBM sphere cultures. With a computational structure-based drug design, 11 small-molecule compounds were designed, synthesized, and evaluated as inhibitor candidates for the molecular interaction of Survivin protein. The molecular mechanism of the lead compound, LLP-3, was determined by Western blot, ELISA, in situ proximity ligation assay, and immunocytochemistry. The effects of LLP-3 treatment on GSCs were evaluated both in vitro and in vivo. Quantitative immunohistochemistry was carried out to compare Survivin expression in tissues from 44 newly diagnosed and 31 recurrent post-chemoradiation GBM patients. Lastly, the sensitivities of temozolomide-resistant GBM spheres to LLP-3 were evaluated in vitro. Results: Survivin and Ran were strongly expressed in GBM tissues, particularly in the perivasculature, and also in patient-derived GSC cultures. LLP-3 treatment disrupted the Survivin–Ran protein complex in cancer cells and abolished the growth of patient-derived GBM spheres in vitro and in vivo. This inhibition was dependent on caspase activity and associated with p53 status of cells. Immunohistochemistry showed that Survivin expression is significantly increased in recurrent GBM compared with newly diagnosed tumors, and temozolomide-resistant GBM spheres exhibited high sensitivities to LLP-3 treatment. Conclusions: Disruption of the Survivin–Ran complex by LLP-3 abolishes survival and growth of GSCs both in vitro and in vivo, indicating an attractive novel therapeutic approach for GBM. Clin Cancer Res; 19(3); 631–42. ©2012 AACR.

Objective. To determine the frequency of initial misclassification of diabetes mellitus (DM) in children and to compare the presenting features of DM1, DM2, and the misclassified cases. Results. A total of 206 patients fulfilled the inclusion criteria. Of them, 74.75% had DM1 and 25.25% had DM2. Ten percent of studied patients had a subsequent change in classification. The mean HbA1c of the DM2 patients, who were initially misclassified, was 13.35% (SD = 1.96). The mean HbA1c of DM2 patients with correct initial classification was 8.83% (SD = 3.01). Diabetes ketoacidosis (DKA) was seen in 59.44% of DM1 and 23.91% of DM2 patients. Of the DM2 patients who were initially misclassified, 58.82% had presented in DKA as opposed to only 6.45% of patients who were correctly classified. Conclusion. The initial classification of DM frequently requires revision (10% in this study). The misclassification is highest among DM2 patients who initially present with higher HbA1c and DKA.

The optimal regimen of the anticoagulant and antiplatelet therapies in patients with atrial fibrillation who have had a coronary stent is unclear. It is well recognized that “triple therapy” with aspirin, clopidogrel, and warfarin is associated with an increased risk of bleeding. National guidelines have not made specific recommendations, given the lack of adequate data. In choosing the best antithrombotic options for a patient, consideration needs to be given to the risks of stroke, stent thrombosis, and major bleeding. This executive summary describes these risks, provides specific recommendations concerning vascular access, stent choice, concomitant use of proton pump inhibitors, and the use and duration of triple therapy after stent placement, based on the risk assessment.

Background— Studies report a protective effect of higher attained educational level (AEL) on cardiovascular outcomes. However, most of these studies have been conducted in high-income countries (HICs) and lack representation from low- and middle-income countries (LMICs), which bear >80% of the global burden of cardiovascular disease. Methods and Results— The Reduction of Atherothrombosis for Continued Health (REACH) Registry is a prospective study of 67 888 subjects with either established atherothrombotic (coronary, cerebrovascular, and/or peripheral arterial) disease or multiple atherothrombotic risk factors enrolled from 5587 physician practices in 44 countries. At baseline, AEL (0 to 8 years, 9 to 12 years, trade or technical school, and university) was self-reported for 61 332 subjects. Outcomes included the baseline prevalence of atherothrombotic risk factors and the rate of incident cardiovascular events (cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke) through 23 months across AEL groups, stratified by sex and world region (LMICs or HICs). Educational attainment was inversely associated with age and diabetes mellitus and directly associated with hypercholesterolemia in all subjects. However, for other risk factors such as obesity, smoking, hypertension, and baseline burden of vascular disease, AEL was protective (inversely associated) in HICs but not protective in LMICs. The protective effect of greater AEL on incident cardiovascular events was strongest in men from HICs ( P <0.0001), more modest in women from HICs ( P =0.0026) and in men from LMICs ( P =0.082), and essentially absent in women from LMICs ( P =0.32). Conclusion— In contrast to HICs, higher AEL may not be protective against cardiovascular events in LMICs, particularly in women.

Sphingolipids (SLs) play important roles in membrane structure and cell function. Here, we examine the SL requirements of various endocytic mechanisms using a mutant cell line and pharmacological inhibitors to disrupt SL biosynthesis. First, we demonstrated that in Chinese hamster ovary cells we could distinguish three distinct mechanisms of clathrin-independent endocytosis (caveolar, RhoA, and Cdc42 dependent) which differed in cargo, sensitivity to pharmacological agents, and dominant negative proteins. General depletion of SLs inhibited endocytosis by each clathrin-independent mechanism, whereas clathrin-dependent uptake was unaffected. Depletion of glycosphingolipids (GSLs; a subgroup of SLs) selectively blocked caveolar endocytosis and decreased caveolin-1 and caveolae at the plasma membrane. Caveolar endocytosis and PM caveolae could be restored in GSL-depleted cells by acute addition of exogenous GSLs. Disruption of RhoA- and Cdc42-regulated endocytosis by SL depletion was shown to be related to decreased targeting of these Rho proteins to the plasma membrane and could be partially restored by exogenous sphingomyelin but not GSLs. Both the in vivo membrane targeting and in vitro binding to artificial lipid vesicles of RhoA and Cdc42 were shown to be dependent upon sphingomyelin. These results provide the first evidence that SLs are differentially required for distinct mechanisms of clathrin-independent endocytosis.

Brain metastases are an important cause of morbidity and mortality, afflicting nearly 170,000 Americans annually. The prognosis for these patients is poor, with median survival times measured in months. In this review article, we present the standard treatment approach of whole-brain radiotherapy and discuss new directions, including the role of chemical modifiers and the management and prevention of neurocognitive deficits.

Abstract Transforming growth factor-β (TGF-β) stimulates cellular proliferation and transformation to a myofibroblast phenotype in vivo and in a subset of fibroblast cell lines. As the Smad pathway is activated by TGF-β in essentially all cell types, it is unlikely to be the sole mediator of cell type–specific outcomes to TGF-β stimulation. In the current study, we determined that TGF-β receptor signaling activates phosphatidylinositol 3-kinase (PI3K) in several fibroblast but not epithelial cultures independently of Smad2 and Smad3. PI3K activation occurs in the presence of dominant-negative dynamin and is required for p21-activated kinase-2 kinase activity and the increased proliferation and morphologic change induced by TGF-β in vitro.

Abstract Glycosphingolipids are known to play roles in integrin-mediated cell adhesion and migration; however, the mechanisms by which glycosphingolipids affect integrins are unknown. Here, we show that addition of the glycosphingolipid, C8-lactosylceramide (C8-LacCer), or free cholesterol to human fibroblasts at 10°C causes the formation of glycosphingolipid-enriched plasma membrane domains as shown by visualizing a fluorescent glycosphingolipid probe, BODIPY-LacCer, incorporated into the plasma membrane of living cells. Addition of C8-LacCer or cholesterol to cells initiated the clustering of β1-integrins within these glycosphingolipid-enriched domains and the activation of the β1-integrins as assessed using a HUTS antibody that only binds activated integrin. On warming to 37°C, β1-integrins were rapidly internalized via caveolar endocytosis in cells treated with C8-LacCer or cholesterol, whereas little β1-integrin was endocytosed in untreated fibroblasts. Incubation of cells with C8-LacCer or cholesterol followed by warm-up caused src activation, a reorganization of the actin cytoskeleton, translocation of RhoA GTPase away from the plasma membrane as visualized using total internal reflection fluorescence microscopy, and transient cell detachment. These studies show that LacCer can regulate integrin function both by modulating integrin clustering in microdomains and by regulating integrin endocytosis via caveolae. Our findings suggest the possibility that aberrant levels of glycosphingolipids found in cancer cells may influence cell attachment events by direct effects on integrin clustering and internalization.