Purpose: To examine the role of cancer stem cells (CSC) in mediating metastasis in inflammatory breast cancer (IBC) and the association of these cells with patient outcome in this aggressive type of breast cancer.Experimental Design: CSCs were isolated from SUM149 and MARY-X, an IBC cell line and primary xenograft, by virtue of increased aldehyde dehydrogenase (ALDH) activity as assessed by the ALDEFLUOR assay. Invasion and metastasis of CSC populations were assessed by in vitro and mouse xenograft assays. Expression of ALDH1 was determined on a retrospective series of 109 IBC patients and this was correlated with histoclinical data. All statistical tests were two sided. Log-rank tests using Kaplan-Meier analysis were used to determine the correlation of ALDH1 expression with development of metastasis and patient outcome.Results: Both in vitro and xenograft assays showed that invasion and metastasis in IBC are mediated by a cellular component that displays ALDH activity. Furthermore, expression of ALDH1 in IBC was an independent predictive factor for early metastasis and decreased survival in this patient population.Conclusions: These results suggest that the metastatic, aggressive behavior of IBC may be mediated by a CSC component that displays ALDH enzymatic activity. ALDH1 expression represents the first independent prognostic marker to predict metastasis and poor patient outcome in IBC. The results illustrate how stem cell research can translate into clinical practice in the IBC field. Clin Cancer Res; 16(1); 45-55. ©2010 AACR.Inflammatory breast cancer (IBC) is an angioinvasive form of breast cancer associated with a high incidence of early nodal and systemic metastasis. In contrast to the recent decrease in breast cancer incidence in the United States, the annual incidence of IBC continues to increase (1, 2) with an attendant increase in mortality (3). Despite advances in the use of systemic chemotherapy, the prognosis of IBC remains considerably worse than that of other locally advanced breast cancers (1).Several molecular changes have been described in IBC including RHOC overexpression, hypomethylation of caveolin-1 or caveolin-2 promoters, and deletion of the tumor suppressor WISP3 (4-8). In addition, IBCs have been reported to overexpress E-cadherin/α, β-catenin, and angiogenic factors (4,7,(9)(10)(11)(12)(13)(14). Although each of these genetic changes may contribute to the metastatic nature of IBC, no markers have been described that can predict the development of systemic metastasis or survival in IBC patients. Although ERBB2 expression is associated with aggressive behavior in most breast cancers, this is not the case in IBC (15).There is increasing evidence that human breast cancers are driven by a tumor-initiating "cancer stem cell" (CSC) component that may contribute to tumor metastasis and therapeutic resistance (16)(17)(18)(19)(20). Breast CSCs were initially characterized as CD44 + /CD24 − /lin − cells that were capable of serial transplantation in nonobese/severe combined immunodefic...

The outbreak of a novel coronavirus, which was later formally named the severe acute respiratory coronavirus 2 (SARS-CoV-2), has caused a worldwide public health crisis. Previous studies showed that SARS-CoV-2 is highly homologous to SARS-CoV and infects humans through the binding of the spike protein to ACE2. Here, we have systematically studied the molecular mechanisms of human infection with SARS-CoV-2 and SARS-CoV by protein-protein docking and MD simulations. It was found that SARS-CoV-2 binds ACE2 with a higher affinity than SARS-CoV, which may partly explain that SARS-CoV-2 is much more infectious than SARS-CoV. In addition, the spike protein of SARS-CoV-2 has a significantly lower free energy than that of SARS-CoV, suggesting that SARS-CoV-2 is more stable and may survive a higher temperature than SARS-CoV. This provides insights into the evolution of SARS-CoV-2 because SARS-like coronaviruses have originated in bats. Our computation also suggested that the RBD-ACE2 binding for SARS-CoV-2 is much more temperature-sensitive than that for SARS-CoV. Thus, it is expected that SARS-CoV-2 would decrease its infection ability much faster than SARS-CoV when the temperature rises. These findings would be beneficial for the disease prevention and drug/vaccine development of SARS-CoV-2.Viruses 2020, 12, 428 2 of 11 origin and is 96% identical at the whole-genome level to a bat SARS-like coronavirus [22]. In addition, SARS-CoV-2 is also closely related to other SARS-like coronaviruses and shares a 79.5% sequence identity to SARS-CoV [22]. For some encoded proteins like coronavirus main proteinase (3CLpro), papain-like protease (PLpro), and RNA-dependent RNA polymerase (RdRp), the sequence identity is even higher and can be as high as 96% between SARS-CoV-2 and SARS-CoV [23]. Therefore, it was thought that SARS-CoV-2 would function in a similar way to SARS-CoV in the human-infection and pathogenic mechanism [22][23][24].Coronaviruses use the surface spike (S) glycoprotein on the coronavirus envelope to attach host cells and mediate host cell membrane and viral membrane fusion during infection [25]. The spike protein includes two regions, S1 and S2, where S1 is for host cell receptor binding and S2 is for membrane fusion. The S1 region also includes an N-terminal domain (NTD) and three C-terminal domains (CTD1, CTD2, and CTD3) [26]. For SARS-CoV, the receptor binding domain (RBD) is located in the CTD1 of the S1 region. SARS-CoV attaches the human host cells through the binding of the RBD protein to the angiotensin-converting enzyme II (ACE2) [27,28]. Therefore, the interaction between RBD and ACE2 is a prerequisite for the human infection with SARS-CoV. Given the high homology between SARS-CoV and SARS-CoV-2, it was expected that SARS-CoV-2 would also use the ACE2 molecule as the receptor to enter human cells [24,29]. This hypothesis was further experimentally confirmed by the virus infectivity studies from the Shi group, in which SARS-CoV-2 is able to use the ACE2 proteins from humans, Chinese horseshoe bats, and civ...

This paper is a report of a second round of RNA-Puzzles, a collective and blind experiment in three-dimensional (3D) RNA structure prediction. Three puzzles, Puzzles 5, 6, and 10, represented sequences of three large RNA structures with limited or no homology with previously solved RNA molecules. A lariat-capping ribozyme, as well as riboswitches complexed to adenosylcobalamin and tRNA, were predicted by seven groups using RNAComposer, ModeRNA/SimRNA, Vfold, Rosetta, DMD, MC-Fold, 3dRNA, and AMBER refinement. Some groups derived models using data from state-of-the-art chemicalmapping methods (SHAPE, DMS, CMCT, and mutate-and-map). The comparisons between the predictions and the three subsequently released crystallographic structures, solved at diffraction resolutions of 2.5-3.2 Å, were carried out automatically using various sets of quality indicators. The comparisons clearly demonstrate the state of present-day de novo prediction abilities as well as the limitations of these state-of-the-art methods. All of the best prediction models have similar topologies to the native structures, which suggests that computational methods for RNA structure prediction can already provide useful structural information for biological problems. However, the prediction accuracy for non-Watson-Crick interactions, key to proper folding of RNAs, is low and some predicted models had high Clash Scores. These two difficulties point to some of the continuing bottlenecks in RNA structure prediction. All submitted models are available for download at http://ahsoka.u-strasbg .fr/rnapuzzles/.