CXCR2-Blocking Has Context-Sensitive Effects on Rat Glioblastoma Cell Line Outgrowth (S635) in an Organotypic Rat Brain Slice Culture Depending on Microglia-Depletion (PLX5622) and Dexamethasone Treatment

In glioblastoma (GBM), the interplay of different immune cell subtypes, cytokines, and/or drugs shows high context-dependencies. Interrelations between the routinely applied dexamethasone (Dex) and microglia remain elusive. Here, we exploited rat organotypic brain slice co-cultures (OBSC) to examine the effects on a rat GBM cell line (S635) outgrowth resulting from the presence of Dex and pretreatment with the colony-stimulating factor receptor 1 (CSF1-R) inhibitor PLX5622: in native OBSC (without PLX5622-pretreatment), a diminished S635 spheroid outgrowth was observable, whereas Dex-treatment enhanced outgrowth in this condition compared to PLX5622-pretreated OBSC. Screening the supernatants of our model with a proteome profiler, we found that CXCL2 was differentially secreted in a Dex- and PLX5622-dependent fashion. To analyze causal interrelations, we interrupted the CXCL2/CXCR2-axis: in the native OBSC condition, CXCR2-blocking resulted in increased outgrowth, in combination with Dex, we found potentiated outgrowth. No effect was found in the PLX5622-pretreated. Our method allowed us to study the influence of three different factors—dexamethasone, PLX5622, and CXCL2—in a well-controlled, simplified, and straight-forward mechanistic manner, and at the same time in a more realistic ex vivo scenario compared to in vitro studies. In our model, we showed a GBM outgrowth enhancing synergism between CXCR2-blocking and Dex-treatment in the native condition, which was levelled by PLX5622-pretreatment

Function of carbonic anhydrase IX in glioblastoma multiforme

Carbonic anhydrase (CA) IX is over-expressed in glioblastoma; however, its functions in this context are unknown. Metabolically, glioblastomas are highly glycolytic, leading to a significant lactic acid load. Paradoxically, the intracellular pH is alkaline. We hypothesized that CAIX contributes to the extrusion of hydrogen ions into the extracellular space, thereby moderating intra- and extracellular pH and creating an environment conductive to enhanced invasion. We investigated the role of CAIX as a prognostic marker in patients with glioblastoma and its biological function in vitro. CAIX expression was analyzed in 59 patients with glioblastoma by immunohistochemistry. The expression levels were correlated to overall survival. In vitro, U251 and Ln 18 glioblastoma cells were incubated under hypoxia to induce CAIX expression, and RNA interference (RNAi) was used to examine the function of CAIX on cell attachment, invasion, intracellular energy transfer, and susceptibility to adjuvant treatment. High CAIX expression was identified as an independent factor for poor survival in patients with glioblastoma. In vitro, cell attachment and invasion were strongly reduced after knockdown of CAIX. Finally, the effects of radiation and chemotherapy were strongly augmented after CAIX interference and were accompanied by a higher rate of apoptotic cell death. CAIX is an independent prognostic factor for poor outcome in patients with glioblastoma. Cell attachment, invasion, and survival during adjuvant treatment are significantly influenced by high CAIX expression. These results indicate that inhibition of CAIX is a potential metabolic target for the treatment of patients with glioblastoma

Excessive release of endogenous neuropeptide Y into cerebrospinal fluid after treatment of spontaneous subarachnoid haemorrhage and its possible impact on self-reported neuropsychological performance – results of a prospective clinical pilot study on good-grade patients

Objectives: Neuropsychological dysfunction after treatment of spontaneous subarachnoid haemorrhage (sSAH) is common but underreported. The vasoconstrictor neuropeptide Y (NPY) is excessively released after sSAH and in psychiatric disorders. We prospectively analysed the treatment-specific differences in the secretion of endogenous cerebrospinal fluid (CSF) NPY during the acute stage after sSAH and its impact on cognitive processing. Methods: A total of 26 consecutive patients (f:m = 13:8; mean age 50.6 years) with good-grade sSAH were enrolled (drop out n = 5): n = 9 underwent endovascular aneurysm occlusion, n = 6 microsurgery, and n = 6 patients with perimesencephalic SAH received standardized intensive medical care. Ventricular CSF was drawn daily from day 1-10. CSF NPY levels were determined with competitive enzyme immunoassay. All patients underwent neuropsychological self-report assessment [36-Item Short Form Health Survey (SF-36) and ICD-10-Symptom-Rating questionnaire (ISR)] after the onset of sSAH (day 11-35; t(1)) and at the 6-month follow-up (t(2)). Results: At t(1), increased mean levels of NPY in CSF significantly correlated with impaired performance in most ISR scores (ISR total p = .018, depression p = .035, anxiety p = .008, nutrition disorder p = .047, supplementary items p = .038) and in several psychological SF-36 items (vitality p = .019, general mental health p = .001, mental component summary p = .025). Discussion: To the best of our knowledge, this study is the first to correlate the levels of endogenous NPY in supratentorial CSF with cognitive outcome in good-grade sSAH patients. Excessive NPY release into CSF may have a short-term influence on the pathogenesis of neuropsychological deficits. The impact of cerebrovascular manipulation on NPY release has to be further elucidated