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FGF13, a member of the FGF subfamily, has been found to be highly expressed in cancer cells such as prostate cancer, melanoma, glioma and multiple myeloma. However, the mechanism of FGF13 function during cancer cell proliferation remains to be unexplored, especially Non-small cell lung cancer (NSCLC). In this study, the cell proliferation effect of FGF13 on A549 cells was checked by CCK-8, clone formation, Ki67 immunofluorescence staining and Flow Cytometry assay. Localization of FGF13 within A549 cells was performed with confocal laser scanning microscope. The protein variations and interaction were measured by western blotting and co-immunoprecipitation analysis. It showed that FGF13 was mainly distributed in the cytoplasm and exhibited a high expression level in A549 cells. High expression of FGF13 activated AKT-GSK3 signaling pathway, and inhibited the activity of p21 and p27. Thus, FGF13 enhanced the process of transition from G1 to S phase and promoted A549 cells proliferation. Furthermore, the interaction between FGF13 and SHCBP1 was confirmed. Meanwhile, FGF13 and SHCBP1 had a cooperative effect to accelerate the cell cycle progression, especially the ability to promote cell proliferation is significantly enhanced via protein interaction. Hence, we conclude that FGF13 played a positive regulation role during A549 cells proliferation. FGF13 interacted with SHCBP1 to facilitate cell cycle progression, providing new insights into deep understanding of non-small cell lung cancer mechanisms of proliferation and regulation function of FGF13.

Tissue cells continually monitor anchorage conditions by gauging the physical properties of their underlying matrix and surrounding environment. The Rho and Ras GTPases are essential components of these mechanosensory pathways. These molecular switches control both cytoskeletal as well as cell fate responses to anchorage conditions and are thus critical to our understanding of how cells respond to their physical environment and, by extension, how malignant cells gainsay these regulatory pathways. Recent studies indicate that 2 proteins produced by the SHC1 gene, thought for the most part to functionally oppose each other, collaborate in their ability to respond to mechanical force by initiating respective Rho and Ras signals. In this review, we focus on the coupling of Shc and GTPases in the cellular response to mechanical anchorage signals, with emphasis on its relevance for cancer.

Signaling via the pre-T-cell receptor (pre-TCR), along with associated signals from Notch and chemokine receptors, regulates the β-selection checkpoint that operates on CD4(-) CD8(-) doubly negative (DN) thymocytes. Since many hematopoietic malignancies arise at the immature developmental stages of lymphocytes, understanding the signal integration and how specific signaling molecules and distal transcription factors regulate cellular outcomes is of importance. Here, a series of molecular and genetic approaches revealed that the ShcA adapter protein critically influences proliferation and differentiation during β-selection. We found that ShcA functions downstream of the pre-TCR and p56(Lck) and show that ShcA is important for extracellular signal-regulated kinase (ERK)-dependent upregulation of transcription factors early growth factor 1 (Egr1) and Egr3 in immature thymocytes and, in turn, of the expression and function of the Id3 and E2A helix-loop-helix (HLH) proteins. ShcA also contributes to pre-TCR-mediated induction of c-Myc and additional cell cycle regulators. Moreover, using an unbiased Saccharomyces cerevisiae (yeast) screen, we identified c-Abl as a binding partner of phosphorylated ShcA and demonstrated the relevance of the ShcA-c-Abl interaction in immature thymocytes. Collectively, these data identify multiple modes by which ShcA can fine-tune the development of early thymocytes, including a previously unappreciated ShcA-c-Abl axis that regulates thymocyte proliferation., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Breast cancers are stratified into distinct subtypes, which influence therapeutic responsiveness and patient outcome. Patients with luminal breast cancers are often associated with a better prognosis relative to that with other subtypes. However, subsets of patients with luminal disease remain at increased risk of cancer-related death. A critical process that increases the malignant potential of breast cancers is the epithelial-to-mesenchymal transition (EMT). The p66ShcA adaptor protein stimulates the formation of reactive oxygen species in response to stress stimuli. In this paper, we report a novel role for p66ShcA in inducing an EMT in HER2(+) luminal breast cancers. p66ShcA increases the migratory properties of breast cancer cells and enhances signaling downstream of the Met receptor tyrosine kinase in these tumors. Moreover, Met activation is required for a p66ShcA-induced EMT in luminal breast cancer cells. Finally, elevated p66ShcA levels are associated with the acquisition of an EMT in primary breast cancers spanning all molecular subtypes, including luminal tumors. This is of high clinical relevance, as the luminal and HER2 subtypes together comprise 80% of all newly diagnosed breast cancers. This study identifies p66ShcA as one of the first prognostic biomarkers for the identification of more aggressive tumors with mesenchymal properties, regardless of molecular subtype., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

Computer-assisted simulation is a promising approach for clarifying complicated signaling networks. However, this approach is currently limited by a deficiency of kinetic parameters determined in living cells. To overcome this problem, we applied fluorescence cross-correlation spectrometry (FCCS) to measure dissociation constant (Kd) values of signaling molecule complexes in living cells (in vivo Kd). Among the pairs of fluorescent molecules tested, that of monomerized enhanced green fluorescent protein (mEGFP) and HaloTag-tetramethylrhodamine was most suitable for the measurement of in vivo Kd by FCCS. Using this pair, we determined 22 in vivo Kd values of signaling molecule complexes comprising the epidermal growth factor receptor (EGFR)-Ras-extracellular signal-regulated kinase (ERK) mitogen-activated protein (MAP) kinase pathway. With these parameters, we developed a kinetic simulation model of the EGFR-Ras-ERK MAP kinase pathway and uncovered a potential role played by stoichiometry in Shc binding to EGFR during the peak activations of Ras, MEK, and ERK. Intriguingly, most of the in vivo Kd values determined in this study were higher than the in vitro Kd values reported previously, suggesting the significance of competitive bindings inside cells. These in vivo Kd values will provide a sound basis for the quantitative understanding of signal transduction., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

The centralspindlin complex, which is composed of MKLP1 and MgcRacGAP, is one of the crucial factors involved in cytokinesis initiation. Centralspindlin is localized at the middle of the central spindle during anaphase and then concentrates at the midbody to control abscission. A number of proteins that associate with centralspindlin have been identified. These associating factors regulate furrowing and abscission in coordination with centralspindlin. A recent study identified a novel centralspindlin partner, called Nessun Dorma, which is essential for germ cell cytokinesis in Drosophila melanogaster. SHCBP1 is a human ortholog of Nessun Dorma that associates with human centralspindlin. In this report, we analyzed the interaction of SHCBP1 with centralspindlin in detail and determined the regions that are required for the interaction. In addition, we demonstrate that the central region is necessary for the SHCBP1 dimerization. Both MgcRacGAP and MKLP1 are degraded once cells exit mitosis. Similarly, endogenous and exogenous SHCBP1 were degraded with mitosis progression. Interestingly, SHCBP1 expression was significantly reduced in the absence of centralspindlin, whereas centralspindlin expression was not affected by SHCBP1 knockdown. Finally, we demonstrate that SHCBP1 depletion promotes midbody structure disruption and inhibits abscission, a final stage of cytokinesis. Our study gives novel insight into the role of SHCBP in cytokinesis completion.

Early molecular events with correlation to disease, such as aberrant DNA methylation, emphasize the importance of DNA methylation as a potential environmental biomarker. Currently, little is known regarding how various environmental contaminants and mixtures alter DNA methylation in aquatic organisms, and testing is both time- and labor-consuming. Therefore, the potential of an in vitro screening method was evaluated by exposing zebrafish liver cells (ZF-L) for 96 h to the nonmutagenic model substance 5'-azacytidine (AZA), as well as a selection of environmental pollutants such as sodium arsenite (NAS), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 17α-ethinylestradiol (EE2), and diethylstilbestrol (DES). Six single genes with reported and anticipated importance in cancer were selected for analysis. Methylation of gene promoter areas was monitored by bisulfite conversion and high-resolution melt (HRM) analysis after exposure to sublethal concentrations of the test compounds. Subsequently, results were validated with direct bisulfite sequencing. Exposure of ZF-L cells to 0.5 μM AZA for 96 h led to hypomethylation of genes with both low and high basal methylation indicating similarity to mechanism of action in mammals. Further, NAS, EE2, and DES were shown to induce significant alterations in methylation, whereas TCDD did not. It was concluded that cell line exposure in combination with HRM may provide an initial contaminant screening assay by quantifying DNA methylation alterations with high throughput capacity. In addition, the rapid determination of effects following contaminant exposure with this in vitro system points to the possibility for new in vivo applications to be useful for environmental monitoring.

Autophagy is the major intracellular system of degradation, and it plays an essential role in various biological events. Recent observations indicate that autophagy is modulated in response to the energy status of the mitochondrial compartment. However, the exact signaling mechanism that controls autophagy under these conditions remains unclear. In this study, we report that the activation of protein kinase C β (PRKCB), a member of the classical PRKCs, negatively modulates the mitochondrial energy status and inhibits autophagy. Furthermore, cells treated with a pharmacological PRKCB inhibitor, and prkcb knockout MEFs showed an increase in autophagy both in vitro and in vivo, as well as an increased mitochondrial membrane potential (Ψm), suggesting a strong involvement of mitochondrial energy in the modulation of the autophagy machinery. Finally, we show that factors that increase the Ψm oppose the PRKCB-dependent inhibition of autophagy. Altogether, these data underscore the importance of PRKCB in the regulation of autophagy; moreover, the finding that a pharmacological modulation of the Ψm modifies autophagy levels may be useful in fighting pathologies (including various types of cancer and neurodegenerative disorders) that are characterized by reduced levels of autophagy.

Stroke is the leading cause of adult disability in the U.S. and is now recognized as a global epidemic. There are currently no FDA-approved drugs to block the cell death that results from oxygen and glucose deprivation. This void in clinical medicine has sparked an intense interest in understanding endogenous cellular protective pathways that might be exploited for therapeutic development. The work highlighted here describes the critical role between redox tone and energetic stress signaling in mediating mitophagy and determining neuronal cell fate following acute oxygen glucose deprivation.

Endothelial cells, which are located at the interface between the blood and the vessel wall, respond dynamically to a variety of stimuli initiating signaling cascades that regulate cardiovascular development, physiology and pathology. These inputs include soluble factors that bind to their receptors, integrin-matrix interactions, cell-cell contacts and mechanical forces due to the flowing blood. While these stimuli can mediate unique downstream signals, it is well-accepted that signaling pathways are highly interwoven into complex signaling networks with several levels of cross-talk, integration and coordination. Recent studies suggest that several signaling networks coalesce at the adaptor protein Shc.