Function of the anterior gradient protein family in cancer

Proteomic technologies verified Anterior Gradient 2, AGR-2, as a protein over-expressed in human cancers, including breast, prostate and oesophagus cancers, with the ability to inhibit the tumour suppressor protein p53. AGR-2 gene is a hormone responsive gene with an unexpected induction by the anti-cancer drug tamoxifen highlighting the proto-oncogenic role of this protein. Anterior Gradient-2 encodes one protein that gives rise to two forms· the full length and the mature one. Full length bears a leader sequence that leads the protein to secretion. Localization studies of both forms of AGR-2 were performed using fluorescence microscopy and subcellular fractionation, in order to determine in which compartment the protein functions. Localization mutants of the mature and full length protein determined the exact sequence required for certain localization patterns. Once localization was confirmed, the mechanism of how Anterior Gradient-2 localization within the cell can inhibit p53 was initiated. Furthermore, novel peptide aptamers that bound to the protein were cloned into GFP vectors and their effect on AGR-2 was investigated. AGR-3, another member of the family, was also examined in terms of localization and function in MCF-7 cells. Yeast two hybrid analysis has identified potential nuclear and cytoplasmic binding partners for AGR-2, essential for the upstream or downstream regulation of the AGR-2 pathway. In conclusion, we present data showing models of how the Anterior Gradient protein family might function as drug-resistance survival factor in cancer as well as a p53 inhibitor, suggesting a multi-potent role of its members when it comes to trafficking, cellular localization and activation or inhibition pathways in cancer

Factors Affecting EWS-FLI1 Activity in Ewing's Sarcoma

Ewing's sarcoma family tumors (ESFT) are characterized by specific chromosomal translocations, which give rise to EWS-ETS chimeric proteins. These aberrant transcription factors are the main pathogenic drivers of ESFT. Elucidation of the factors influencing EWS-ETS expression and/or activity will guide the development of novel therapeutic agents against this fatal disease

The First European Interdisciplinary Ewing Sarcoma Research Summit

The European Network for Cancer Research in Children and Adolescents (ENCCA) provides an interaction platform for stakeholders in research and care of children with cancer. Among ENCCA objectives is the establishment of biology-based prioritization mechanisms for the selection of innovative targets, drugs, and prognostic markers for validation in clinical trials. Specifically for sarcomas, there is a burning need for novel treatment options, since current chemotherapeutic treatment protocols have met their limits. This is most obvious for metastatic Ewing sarcoma (ES), where long term survival rates are still below 20%. Despite significant progress in our understanding of ES biology, clinical translation of promising laboratory results has not yet taken place due to fragmentation of research and lack of an institutionalized discussion forum. To fill this gap, ENCCA assembled 30 European expert scientists and five North American opinion leaders in December 2011 to exchange thoughts and discuss the state of the art in ES research and latest results from the bench, and to propose biological studies and novel promising therapeutics for the upcoming European EWING2008 and EWING2012 clinical trials

Function of the anterior gradient protein family in cancer

Proteomic technologies verified Anterior Gradient 2, AGR-2, as a protein over-expressed in human cancers, including breast, prostate and oesophagus cancers, with the ability to inhibit the tumour suppressor protein p53. AGR-2 gene is a hormone responsive gene with an unexpected induction by the anti-cancer drug tamoxifen highlighting the proto-oncogenic role of this protein. Anterior Gradient-2 encodes one protein that gives rise to two forms· the full length and the mature one. Full length bears a leader sequence that leads the protein to secretion. Localization studies of both forms of AGR-2 were performed using fluorescence microscopy and subcellular fractionation, in order to determine in which compartment the protein functions. Localization mutants of the mature and full length protein determined the exact sequence required for certain localization patterns. Once localization was confirmed, the mechanism of how Anterior Gradient-2 localization within the cell can inhibit p53 was initiated. Furthermore, novel peptide aptamers that bound to the protein were cloned into GFP vectors and their effect on AGR-2 was investigated. AGR-3, another member of the family, was also examined in terms of localization and function in MCF-7 cells. Yeast two hybrid analysis has identified potential nuclear and cytoplasmic binding partners for AGR-2, essential for the upstream or downstream regulation of the AGR-2 pathway. In conclusion, we present data showing models of how the Anterior Gradient protein family might function as drug-resistance survival factor in cancer as well as a p53 inhibitor, suggesting a multi-potent role of its members when it comes to trafficking, cellular localization and activation or inhibition pathways in cancer.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

An alternative transcript from the death-associated protein kinase 1 locus encoding a small protein selectively mediates membrane blebbing: Functional transcript expressed by DAPK-1 locus

Death-associated protein kinase 1 (DAPK-1) is a multidomain protein kinase with diverse roles in autophagic, apoptotic and survival pathways. Bioinformatic screens were used to identify a small internal mRNA from the DAPK-1 locus (named s-DAPK-1). This encodes a 295 amino acid polypeptide encompassing part of the ankyrin-repeat domain, the P-loop motifs, part of the cytoskeletal binding domain of DAPK-1, and a unique C-terminal ‘tail’ extension not present in DAPK-1. Expression of s-DAPK-1 mRNA was detected in a panel of normal human tissues as well as primary colorectal cancers, indicating that its expression occurs in vivo. s-DAPK-1 gene transfection into cells produces two protein products: one with a denatured mass of 44 kDa, and a smaller product of 40 kDa. Double alanine mutation of the C-terminal tail extension of s-DAPK-1 (Gly296/Arg297) prevented production of the 40 kDa fragment, suggesting that the smaller product is generated by in vivo proteolytic processing. The s-DAPK-1 gene cannot substitute for full-length DAPK-1 in an mitogen-activated protein kinase kinase/extracellular signal-regulated kinase-dependent apoptotic transfection assay. However, the transfection of s-DAPK-1 was able to mimic full-length DAPK-1 in the induction of membrane blebbing. The 44 kDa protease-resistant mutant s-DAPK-1G296A/R297A had very low activity in membrane blebbing, whereas the 40 kDa s-DAPK-1Δtail protein exhibited the highest levels of membrane blebbing. Deletion of the tail extension of s-DAPK-1 increased its half-life, shifted the equilibrium of the protein from cytoskeletal to soluble cytosolic pools, and altered green fluorescent protein-tagged s-DAPK-1 protein localization as observed by confocal microscopy. These data highlight the existence of an alternative product of the DAPK-1 locus, and suggest that proteolytic removal of the C-terminal tail of s-DAPK-1 is required to stimulate maximally its membrane-blebbing function