Interaction of Discoidin Domain Receptor 1 with a 14-3-3-Beclin-1-Akt1 Complex Modulates Glioblastoma Therapy Sensitivity

Summary: Glioblastoma (GBM) is highly refractory to therapy and associated with poor clinical outcome. Here, we reveal a critical function of the promitotic and adhesion-mediating discoidin domain receptor 1 (DDR1) in modulating GBM therapy resistance. In GBM cultures and clinical samples, we show a DDR1 and GBM stem cell marker co-expression that correlates with patient outcome. We demonstrate that inhibition of DDR1 in combination with radiochemotherapy with temozolomide in GBM models enhances sensitivity and prolongs survival superior to conventional therapy. We identify a 14-3-3-Beclin-1-Akt1 protein complex assembling with DDR1 to be required for prosurvival Akt and mTOR signaling and regulation of autophagy-associated therapy sensitivity. Our results uncover a mechanism driven by DDR1 that controls GBM therapy resistance and provide a rationale target for the development of therapy-sensitizing agents. : Vehlow and Klapproth et al. identify the discoidin domain receptor 1 (DDR1) to assemble with a 14-3-3-Beclin-1-Akt1 protein complex, which mediates prosurvival Akt and mTOR signaling for regulating autophagy-associated glioblastoma cell sensitivity to therapy. Keywords: discoidin domain receptor 1, glioblastoma, radiochemotherapy, therapy resistance, autophagy, 14-3-3, Beclin-1, Akt1, mTOR, GBM stem-like cells, orthotopic GBM mouse model