Therapeutic disruption of Connexin mediated microtubule regulation to target glioblastoma cancer stem cells

Project Summary Glioblastoma GBM is one of the most lethal incurable human diseases Even with aggressive therapies including surgical resection followed by radiotherapy and chemotherapy using temozolomide TMZ the median survival for GBM patients is only months In fact GBM cancer cells are highly infiltrative and comprise a sub population of glioma stem cells GSCs with tumorigenic properties regulated by the tumor microenvironment and often resistant to chemotherapy and irradiation treatments The remaining GSCs can then enter an active state of self renewal and asymmetric division that recapitulates the heterogeneous tumor As a result all treated GBM patients will experience tumor recurrence and subsequent surgeries and toxic radiotherapy and chemotherapy regimens are harmful for the patient and often remain insufficient There is therefore an urgent need for new therapeutic drug to target GSCs and treat this devastating disease Glioblastoma resistance to TMZ correlates with the expression of the gap junction protein Connexin Cx a protein which enables communication between cells and increased levels of Cx are observed in GSCs The function of Cx is not limited to forming channels for the passage of ions and small molecules between cells but also participates in cell proliferation migration and apoptosis Therefore targeting Cx activity holds promise to treat GBM and prevent tumor recurrence In this proposed research we use a novel Cx mimetic peptide named JM juxtamembrane that encompasses the microtubule binding sequence of Cx Our preliminary data show that JM alters Cx binding to microtubule decreases the formation of Cx gap junctions and inhibits cell cell communication in GSCs Most importantly we reveal the therapeutic potential of JM in decreasing GSC survival in vitro and in vivo With the goal of developing a new therapy based upon JM to target GSCs in GBM our overall objective is to generate JM loaded polyanhydride biodegradable nanoparticles JM NPs for sustained delivery of JM to GSCs We will use high resolution microscopy techniques including stochastic optical reconstruction microscopy STORM and biochemistry assays to analyze the effect of JM NPs in GSCs derived from human primary GBM cells freshly isolated from dissected patient tumor Finally we will assess the therapeutic effect of JM NPs on GSCs ex vivo using a three dimensional patient GBM derived organoid model and in vivo using an orthotopic GBM mouse model These results will validate the potent effect of JM peptide for treatment of high Cx chemoresistant GSCs and present a therapeutic opportunity to prevent GBM tumor recurrence The proposed research is significant because this innovative approach will not only allow us to develop novel therapies for lethal GBM but also will lay foundation on potential clinical trials in newly diagnosed GBM patients in the near future Finally our new JM loaded nanoparticles may be scalable to other CNS diseases that could benefit from targeting Cx microtubule interaction Project Narrative Glioblastoma is the most aggressive type of brain tumor and one of the most deadly diseases with no efficient therapy to cure it The proposed research aims at developing a new therapeutic strategy to target tumor initiating cells in glioblastoma Therefore this work will have important impact on therapeutic intervention for glioblastoma and is relevant to public health and NIH s mission