The specific expression of three novel splice variant forms of human metalloprotease-like disintegrin-like cysteine-rich protein 2 gene inBrain tissues and gliomas.
ABSTRACT We have previously identified 67 exons on a yeast artificial chromosome contig spanning 1.5 Mb around the multidrug resistance 1 gene region of human chromosome 7q21.1. In this study, we identified three novel cytoplasmic variants (MDC2-gamma, MDC2-delta, and MDC2-epsilon) of the human metalloprotease-like disintegrin-like cysteine-rich protein 2 (MDC2) among these exons by screening a human brain cDNA library and also by using a reverse transcription polymerase chain reaction. Genomic sequence analysis strongly supported the idea that the variations in the cytoplasmic domain were generated by alternative splicing. The expression of MDC2 variant forms in human brain tissue and gliomas was examined by reverse transcription polymerase chain reaction and RNase protection assay. MDC2-epsilon was expressed only in the cortical and hippocampal regions in human brain, but not in gliomas. In contrast, MDC2-gamma was a major form expressed in human gliomas. Specific expression of these cytoplasmic variants of MDC2 in human brain and its malignancies is discussed.
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ABSTRACT: The A Disintegrin And Metalloprotease (ADAM) proteins belong to the metzincin-superfamily of Zn-dependent metalloproteinases that shed the extracellular domains of membrane-bound growth factors, cytokines and their receptors. The latter play a central role in cell signaling and contribute a potential target in cancer therapy. Of particular interest are the ErBB/HER family of growth factor receptors associated with elevated intrinsic tyrosine kinase activity. Overexpression of ADAMs and cell signaling components have also been implicated in the development and progression of a variety of tumor types. Emerging evidence has suggested that the ADAM proteins are involved in tumour cell proliferation, in angiogenesis as well as metastasis. Therefore, strategies targeting ADAMs may constitute an important target for the design of cancer drugs. The review will focus on current understanding of the role of ADAM in the physiological and pathological functions associated with cancer. It is the intention of the review to provide insights which may assist in the development of ADAM-based approaches for the treatment of human cancers.Current cancer drug targets 01/2009; 8(8):720-32. · 5.13 Impact Factor
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ABSTRACT: Total hip replacement is the golden standard treatment for severe osteoarthritis refractory for conservative treatment. Aseptic loosening and osteolysis are the major long-term complications after total hip replacement. Foreign body giant cells and osteoclasts are locally formed around aseptically loosening implants from precursor cells by cell fusion. When the foreign body response is fully developed, it mediates inflammatory and destructive host responses, such as collagen degradation. In the present study, it was hypothesized that the wear debris and foreign body inflammation are the forces driving local osteoclast formation, peri-implant bone resorption and enhanced tissue remodeling. Therefore the object was to characterize the eventual expression and the role of fusion molecules, ADAMs (an abbreviation for A Disintegrin And Metalloproteinase, ADAM9 and ADAM12) in the fusion of progenitor cells into multinuclear giant cells. For generation of such cells, activated macrophages trying to respond to foreign debris play an important role. Matured osteoclasts together with activated macrophages mediate bone destruction by secreting protons and proteinases, including matrix metalloproteinases (MMPs) and cathepsin K. Thus this study also assessed collagen degradation and its relationship to some of the key collagenolytic proteinases in the aggressive synovial membrane-like interface tissue around aseptically loosened hip replacement implants. ADAMs were found in the interface tissues of revision total hip replacement patients. Increased expression of ADAMs at both transcriptional and translational levels was found in synovial membrane-like interface tissue of revision total hip replacement (THR) samples compared with that in primary THR samples. These studies also demonstrate that multinucleate cell formation from monocytes by stimulation with macrophage-colony stimiulating factor (M-CSF) and receptor activator of nuclear factor kappa B ligand (RANKL) is characterized by time dependent changes of the proportion of ADAMs positive cells. This was observed both in the interface membrane in patients and in two different in vitro models. In addition to an already established MCS-F and RANKL driven model, a new virally (parainfluenza 2) driven model (of human salivary adenocarcinoma (HSY) cells or green monkey kidney (GMK) cells) was developed to study various fusion molecules and their role in cell fusion in general. In interface membranes, collagen was highly degraded and collagen degradation significantly correlated with the number of local cells containing collagenolytic enzymes, particularly cathepsin K. As a conclusion, fusion molecules ADAM9 and ADAM12 seem to be dynamically involved in cell-cell fusion processes and multinucleate cell formation. The highly significant correlation between collagen degradation and collagenolytic enzymes, particularly cathepsin K, indicates that the local acidity of the interface membrane in the pathologic bone and soft tissue destruction. This study provides profound knowledge about cell fusion and mechanism responsible for aseptic loosening as well as increases knowledge helpful for prevention and treatment. The formation of multinucleated cells such as myotubes, macrophage-derived giant cells and osteoclasts is the result of cell-cell fusion of mononuclear precursors. The ADAMs (an acronym for A Disintegrin And Metalloproteinase) is a family of multifunctional proteins that exhibit a significant similarity with snake venom metalloproteases and are involved in cell-cell fusion processes. As fusion molecules, ADAM12 and ADAM9 are involved in cell-cell fusion processes and participate in myoblast fusion and, also in osteoclast fusion. The aims of the proposed project are to characterize ADAMs expression and regulations both in the interface membrane of total hip replacement in the patients and in in vitro cell model. Further study of the relationship between the structure and function of ADAMs may provide profound knowledge of its role in cell fusion, and even one attractive therapeutic target.