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Skeletal Muscle Differentiation (skeletal + muscle_differentiation)
Selected AbstractsMerkel cell (primary neuroendocrine) carcinoma of the skin with nodal metastasis showing rhabdomyosarcomatous differentiationJOURNAL OF CUTANEOUS PATHOLOGY, Issue 10 2002María-Teresa Fernández-Figueras Background:, We describe a unique case of Merkel cell (primary neuroendocrine) carcinoma of the skin with a lymph node metastasis showing rhabdomyosarcomatous differentiation. Skeletal muscle differentiation has occasionally been described in primary small cell neuroendocrine carcinomas and considered a form of dual differentiation rather than a collision tumor. In the present case, capacity for divergent differentiation appeared late in the course of the tumor, which suggests a clonal origin for both components of the neoplasm. Conclusions:, The coexistence of neural and rhabdomyoblastic types of differentiation, best epitomized by the Triton tumor, has been construed as the product of dual differentiation of cells originated from neural crest-derived ectomesenchyme. Since Merkel cells seem to originate from a pluripotential primitive keratinocyte and not from the neural crest, rhabdomyoblastic differentiation in a metastasis of primary neuroendocrine carcinoma of the skin probably reflects the close proximity between the programs of neural and skeletal muscle differentiation, which would have been sequentially activated in the case we are reporting. [source] Mirk/Dyrk1B in cancerJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2007Eileen Friedman Abstract Mirk/Dyrk1B is a member of a conserved family of serine/threonine kinases which are activated by intramolecular tyrosine phosphorylation, and which mediate differentiation in different tissues,Mirk in skeletal muscle, Dyrk1A in the brain, etc. One role of Mirk in skeletal muscle differentiation is to block cycling myoblasts in the G0 quiescent state by modification of cell cycle regulators, while another role of Mirk is to limit apoptosis in fusing myoblasts. Amplification of the Mirk gene, upregulation of Mirk expression and/or constitutive activation of this kinase have been observed in several different types of cancer. If coupled with a stress condition such as serum starvation which induces a quiescent state, depletion of Mirk by RNA interference using either synthetic duplex RNAi's or pSilencer-encoded RNAi's have decreased colony formation of different cancer cell lines and enhanced apoptosis induced by chemotherapeutic drugs. Mirk is activated by phosphorylation by the stress-activated SAPK kinases MKK3 and MKK6. Our working hypothesis is that Mirk is activated by this pathway in response to various stresses, and then acts as a checkpoint kinase to arrest damaged tumor cells in a quiescent state and allow cellular repair. Pharmacological inhibition of Mirk may enhance the anti-tumor effect of chemotherapeutic drugs. J. Cell. Biochem. 102: 274,279, 2007. © 2007 Wiley-Liss, Inc. [source] Merkel cell (primary neuroendocrine) carcinoma of the skin with nodal metastasis showing rhabdomyosarcomatous differentiationJOURNAL OF CUTANEOUS PATHOLOGY, Issue 10 2002María-Teresa Fernández-Figueras Background:, We describe a unique case of Merkel cell (primary neuroendocrine) carcinoma of the skin with a lymph node metastasis showing rhabdomyosarcomatous differentiation. Skeletal muscle differentiation has occasionally been described in primary small cell neuroendocrine carcinomas and considered a form of dual differentiation rather than a collision tumor. In the present case, capacity for divergent differentiation appeared late in the course of the tumor, which suggests a clonal origin for both components of the neoplasm. Conclusions:, The coexistence of neural and rhabdomyoblastic types of differentiation, best epitomized by the Triton tumor, has been construed as the product of dual differentiation of cells originated from neural crest-derived ectomesenchyme. Since Merkel cells seem to originate from a pluripotential primitive keratinocyte and not from the neural crest, rhabdomyoblastic differentiation in a metastasis of primary neuroendocrine carcinoma of the skin probably reflects the close proximity between the programs of neural and skeletal muscle differentiation, which would have been sequentially activated in the case we are reporting. [source] Photolithographic Patterning of C2C12 Myotubes using Vitronectin as Growth Substrate in Serum-Free MediumBIOTECHNOLOGY PROGRESS, Issue 1 2007Peter Molnar The C2C12 cell line is frequently used as a model of skeletal muscle differentiation. In our serum-free defined culture system, differentiation of C2C12 cells into myotubes required surface-bound signals such as substrate-adsorbed vitronectin or laminin. On the basis of this substrate requirement of myotube formation, we developed a photolithography-based method to pattern C2C12 myotubes, where myotubes formed exclusively on vitronectin surface patterns. We have determined that the optimal line width to form single myotubes is approximately 30 ,m. To illustrate a possible application of this method, we patterned myotubes on the top of commercial substrate-embedded microelectrodes. In contrast to previous experiments where cell patterning was achieved by selective attachment of the cells to patterned surfaces in a medium that contained all of the factors necessary for differentiation, this study illustrates that surface patterning of a signaling molecule, which is essential for skeletal muscle differentiation in a defined system, can result in the formation of aligned myotubes on the patterns. This technique is being developed for applications in cell biology, tissue engineering, and robotics. [source] |