Glioblastomas co-opt stem cell regulatory pathways to maintain brain tumor–initiating cells (BTICs), also known as cancer stem cells. NOTCH signaling has been a molecular target in BTICs, but NOTCH antagonists have demonstrated limited efficacy in clinical trials. Recombining binding protein suppressor of hairless (RBPJ) is considered a central transcriptional mediator of NOTCH activity. Here, we report that pharmacologic NOTCH inhibitors were less effective than targeting RBPJ in suppressing tumor growth. While NOTCH inhibitors decreased canonical NOTCH gene expression, RBPJ regulated a distinct profile of genes critical to BTIC stemness and cell cycle progression. RBPJ was preferentially expressed by BTICs and required for BTIC self-renewal and tumor growth. MYC, a key BTIC regulator, bound the
Qi Xie, Qiulian Wu, Leo Kim, Tyler E. Miller, Brian B. Liau, Stephen C. Mack, Kailin Yang, Daniel C. Factor, Xiaoguang Fang, Zhi Huang, Wenchao Zhou, Kareem Alazem, Xiuxing Wang, Bradley E. Bernstein, Shideng Bao, Jeremy N. Rich
NOTCH inhibition does not attenuate cell autonomous BTIC growth.