Semaphorin3A Regulates GBM Stem Cell Invasion Dominique Higgins BS, MS, MD; Mark Schroeder; Fredric B. Meyer MD; Jann Sarkaria MD; John R. Henley PhD Introduction Results Conclusions Glioblastoma (GBM) is the most common primary In vitro studies demonstrated BTSCs highly Taken together these findings demonstrate that brain tumor, and has a poor prognosis for express Sema3A and its receptors Nrp1 and the Sema3A signaling pathway may be a key patients. These tumors are highly aggressive and PlxnA1. Treatment with exogenous Sema3A regulator of GBM stem cell proliferation and invasive by nature, and inevitably recur. Recent demonstrated that Sema3A significantly inhibited invasion, and is thus a promising therapeutic studies suggest that Semaphorin 3A (Sema3A), BTSC proliferation and did not induce cell death. target. classically known for its axon guidance Intriguingly, treatment with Sema3A resulted in properties, plays an important role in GBM increased invasion. Receptor knockdown in Learning Objectives growth. However, the effect of Sema3A on the BTSCs abrogated Sema3A antiproliferative and By the conclusion of this session, participants invasiveness of brain tumor stem cells (BTSCs) pro-invasive effects. Interestingly, though, loss of should be able to: has yet to be defined. We hypothesized that the receptors mimicked Sema3A effects, Sema3A drives invasion via Neuropilin 1 (Nrp1) inhibiting BTSC proliferation and driving invasion. 1)Describe the role of stem cells in GBM and Plexin A1 (PlxnA1) receptors. Further, in vivo studies comparing tumor growth progression of KD and control infected BTSCs implanted into Methods the flanks of nude mice confirmed the decrease in 2)Understand the effects of Semaphorin3A on Primary human GBM cells were passaged in proliferation with receptor KD. GBM stem cell invasion and proliferation athymic nude mouse flanks, according to institutional guidelines. Tumors were harvested 3)Identify potential therapeutic benefit of targeting and cultured in stem cell or differentiation media. guidance cues Immunofluorescence and standard tumorsphere forming assays were used to confirm stem cell phenotypes. Quantitative BrdU and propidium iodide labeling assays were employed to evaluate [Default Poster] proliferation and cell death, respectively. Functional 2-D and 3-D invasion assays were used to quantitate cellular invasion. shRNA lentiviruses targeting either Nrp1 or PlxnA1 receptors were used to knockdown expression, which was confirmed by immunofluorescence and qPCR analysis..