Dedifferentiation of Glioma Cells to Glioma Stem-like Cells By Therapeutic Stress-induced HIF Signaling in the Recurrent GBM Model

作者:Lee Gina; Auffinger Brenda; Guo Donna; Hasan Tanwir; Deheeger Marc; Tobias Alex L; Kim Jeong Yeon; Atashi Fatemeh; Zhang Lingjiao; Lesniak Maciej S; David James C; Ahmed Atique U*
来源:Molecular Cancer Therapeutics, 2016, 15(12): 3064-3076.
DOI:10.1158/1535-7163.MCT-15-0675

摘要

Increasing evidence exposes a subpopulation of cancer cells, known as cancer stem cells (CSCs), to be critical for the progression of several human malignancies, including glioblastoma multiforme. CSCs are highly tumorigenic, capable of self-renewal, and resistant to conventional therapies, and thus considered to be one of the key contributors to disease recurrence. To elucidate the poorly understood evolutionary path of tumor recurrence and the role of CSCs in this process, we developed patient-derived xenograft glioblastoma recurrent models induced by anti-glioma chemotherapy, temozolomide. In this model, we observed a significant phenotypic shift towards an undifferentiated population. We confirmed these findings in vitro as sorted CD133negative populations cultured in differentiation-forcing media were found to acquire CD133 expression following chemotherapy treatment. To investigate this phenotypic switch at the single-cell level, glioma stem cell (GSC)-specific promoter-based reporter systems were engineered to track changes in the GSC population in real time. We observed the active phenotypic and functional switch of single non-stemglioma cells to a stem-like state and that temozolomide therapy significantly increased the rate of single-cell conversions. Importantly, we showed the therapy-induced hypoxia- inducible factors (HIF) 1a and HIF2a play key roles in allowing non-stem glioma cells to acquire stem-like traits, as the expression of both HIFs increase upon temozolomide therapy and knockdown of HIFs expression inhibits the interconversion between nonstem glioma cells and GSCs post-therapy. On the basis of our results, we propose that anti-glioma chemotherapy promotes the accumulation of HIFs in the glioblastoma multiforme cells that induces the formation of therapy-resistant GSCs responsible for recurrence.