ABSTRACT
Microglial activation is a key event in the progression and infiltration of tumors. We have previously demonstrated that the co-chaperone stress inducible protein 1 (STI1), a cellular prion protein (PrP(C)) ligand, promotes glioblastoma (GBM) proliferation. In the present study, we examined the influence of microglial STI1 in the growth and invasion of the human glioblastoma cell line GBM95. We demonstrated that soluble factors secreted by microglia into the culture medium (microglia conditioned medium; MG CM) caused a two-fold increase in the proliferation of GBM95 cells. This effect was reversed when STI1 was removed from the MG CM. In this context, we have shown that microglial cells synthesize and secrete STI1. Interestingly, no difference was observed in proliferation rates when GBM cells were maintained in MG CM or MG CM containing an anti-PrP(C) neutralizing antibody. Moreover, rec STI1 and rec STI1(Δ230-245), which lack the PrP(C) binding site, both promoted similar levels of GBM95 proliferation. In the migration assays, MG CM favored the migration of GBM95 cells, but migration failed when STI1 was removed from the MG CM. We detected metalloproteinase 9 (MMP-9) activity in the MG CM, and when cultured microglia were treated with an anti-STI1 antibody, MMP-9 activity decreased. Our results suggest that STI1 is secreted by microglia and favors tumor growth and invasion through the participation of MMP-9 in a PrP(C)-independent manner.
Subject(s)
Cell Movement/drug effects , Cell Proliferation/drug effects , Glioblastoma/pathology , Heat-Shock Proteins/pharmacology , Microglia/chemistry , PrPC Proteins/metabolism , Animals , Animals, Newborn , Cell Movement/physiology , Cells, Cultured , Cerebral Cortex/cytology , Culture Media, Conditioned/pharmacology , Dose-Response Relationship, Drug , Gene Expression Regulation, Neoplastic/drug effects , Humans , Macrophages/chemistry , Mice , Mice, Knockout , Neurons/chemistry , PrPC Proteins/deficiency , Thymidine/metabolism , Time Factors , Tritium/metabolismABSTRACT
The early diagnosis of vertebral osteoid osteoma is frequently delayed due to the absence of radiographic changes. A bone scan is more helpful because it shows an increased uptake of isotope when plain radiographs still appear normal. The use of computed tomography will confirm the diagnosis, allow precise delineation of the lesion and enable planning of the correct operation.
Subject(s)
Lumbar Vertebrae , Osteoma, Osteoid/diagnostic imaging , Spinal Neoplasms/diagnostic imaging , Child , Humans , Male , Osteoma, Osteoid/surgery , Radiography , Radionuclide Imaging , Scoliosis/etiology , Spinal Neoplasms/surgeryABSTRACT
The effect of electric stimulation with direct constant current in induced pseudarthrosis was investigated in the radius of adult dogs. Two surgical techniques for inducing nonunion in the lower third of the radius of adult dogs are also described. Results were evaluated by clinical, radiologic, and histologic examinations and by 99mTc scintillation. A total of 57 animals (41 electrically stimulated and 16 control animals) was used. Statistically significant data show activation of endochrondral ossification and bone union by electric stimulation.
