No abstract

Schwannomatosis shows clinical and molecular differences from NF2 and should be considered a third major form of neurofibromatosis. Further work is needed to identify the inherited genetic element responsible for familial schwannomatosis.

Suppl 4 -S16 brain indicating that RXFP1 signaling in GB is activated by auto-/paracrine secretion of CTRP8. In GB, RXFP1 signaling included PI3K and PKC activation and resulted in the increased production and secretion of lysosomal protease cathepsin B, a known prognostic marker of GB. In the present study, we have investigated the potential role of RXFP1 in chemoresistance to the commonly used DNA alkylating drug temozolomide (TMZ) in human GB. Upon TMZ treatment, CTRP8/RLN2 mediated activation of RXFP1 was able to mitigate DNA damage in human primary GB cells and enhanced their survival. Activation of RXFP1 resulted in STAT3 pathway activation and the RXFP1-and STAT3-dependent up-regulation of proteins and their activity deemed important for TMZ-induced DNA damage repair. Furthermore, RXFP1 activation resulted in the up-regulation of key anti-apoptotic factors in human GB cells. Our results indicate a novel role for the CTRP8-RXFP1 ligand-receptor system in STAT3-dependent cell invasion, TMZ chemoresistance, and survival and identify RXFP1 as a new protective G protein coupled receptor in GB cells. The most common brain cancer, glioblastoma (GBM), also has the worst five-year survival rates of all cancers. This is due in part to cancer stem cells, known as brain tumor initiating cells (BTICs), which initiate GBM and are resistant to current therapies. Thus, it is important to study therapeutics targeting BTICs. Innate immune cells, microglia and macrophages (MMs), are also important GBM-associated cells. GBM influences MMs to promote tumor growth. However, my research group discovered that an old drug, amphotericin B, re-stimulates MMs to secrete cytokines that inhibit BTIC self-renewal (Nature Neurosci 17:46-55, 2014). Hence, I hypothesize these cytokines are potential GBM treatments. Methods: Twenty genetically diverse BTIC lines were exposed to interleukin-8 (IL8), monocyte chemoattractant protein-1 (MCP1), and tumor necrosis factor-alpha (TNF), the cytokines secreted most abundantly by amphotericin-stimulated MMs. Assays for proliferation, differentiation, apoptosis, and cell cycle arrest were performed. BTICs were then co-cultured with human GBMderived MMs stimulated with TNF. Lastly, the relationship between TNF receptors (TNFR1/2) and presumed BTICs was determined in frozen human GBM sections by immunofluorescence. Results: TNF had the most potent inhibitory effect on BTIC proliferation. Also, TNF was able to increase BTIC differentiation, and induce apoptosis and G1 cell cycle arrest. In MM-BTIC co-culture, TNF stimulated MMs to decrease sphere formation. Interestingly, in human GBM tissue TNFR1 colabeled with OLIG2, a major transcription factor expressed in presumed BTICs, implicating TNF as a BTIC-specific treatment. Conclusion: TNF is a promising candidate for the treatment of GBM. Tumours of the central nervous system are currently classified based on the 2007 WHO Classification of Tumours, which uses histological features to classify and grade these heterogeneous tumors. With recent advances in t...