The expression of two intermediate filaments, nestin and vimentin, was studied in spinal cord injury (SCI) to elucidate their roles in the formation of glial scars. Rats were sacrificed 1, 4, and 7 days after induction of compression injury of the spinal cord using an aneurysm clip. The affected spinal cords were studied using antibodies against nestin and vimentin intermediate filaments. One day after spinal cord injury, some clusters of nestin-positive vessels were detected in the center of the injury, but few were seen in other cell types. Vimentin immunostaining was detected in some glial cells in the center and its level of immunoreactivity was enhanced in the ependymal cells of the central canal. On days 4 and 7 after spinal cord injury, astrocytes and some ependymal cells in the central canal were stained positively for nestin and increased expression of nestin was observed in vessels. Vimentin was detected in some macrophages and astrocytes in the lesions. Nestin was co-localized with glial fibrillary acidic protein in some glial cells in SCI. These findings imply that spinal cord cells in adult animals have embryonic capacity, and these cells are activated after injury, which in turn contributes to repair of spinal cord injury through formation of a glial scar.
Animals ; Cicatrix/pathology ; Glial Fibrillary Acidic Protein/analysis ; Immunohistochemistry ; Intermediate Filament Proteins/analysis ; Intermediate Filaments/*physiology ; *Nerve Tissue Proteins ; Neuroglia/*pathology ; Rats ; Rats, Sprague-Dawley ; Spinal Cord Injuries/*pathology ; Vimentin/analysis

Background: Melanoma is one of the most aggressive and metastatic skin cancers. Although overexpression of Dock180 and Elmo1 has been identified in various cancers, including glioma, ovarian cancer, and breast cancer, their expression and functions in melanoma remain unknown. Objective: This study aims to confirm the expression of Dock180 and Elmo1, their underlying mechanisms, and roles in melanoma. Methods: Both immunohistochemical staining and Western blotting were used to confirm expression of Dock180 and Elmo1 in human melanoma. To identify roles of Dock180 and Elmo1 in cell survival, apoptosis and migration, downregulation of Dock180 or Elmo1 in melanoma cells with small interfering RNA (siRNA) was performed. Results: We identified overexpression of Dock180 and Elmo1 in human melanoma compared to normal skin ex vivo. Inhibition of Dock180 or Elmo1 following siRNA in melanoma cells reduced cell viability and increased apoptosis as supported by increased proportion of cells with Annexin V-PE (+) staining and sub-G0/G1 peak in cell cycle analysis. Moreover, inhibition of Dock180 or Elmo1 regulated apoptosis-related proteins, showing downregulation of Bcl-2, caspase-3, and PARP and upregulation of Bax, PUMA, cleaved caspase-3, and cleaved PARP. Furthermore, knockdown of Dock180 and Elmo1 in melanoma cells reduced cell migration and changed cellular signaling pathways including ERK and AKT. Vemurafenib decreased cell viability in concentration-dependent manner, while transfection with Dock180- or Elmo1-specific siRNA in melanoma cells significantly reduced cell viability. Conclusion Our results suggest that both Dock180 and Elmo1 may be associated with cancer progression, and can be potential targets for treatment of melanoma.