Glioma-associated fibroblasts promote glioblastoma resistance to temozolomide through CCL2-CCR2 paracrine signaling

Abstract

Complicated tumor microenvironment contributes mostly to chemoresistance in glioblastoma. Glioma-associated fibroblasts (GAFs) were recently identified as non-tumor stromal cells in the glioblastoma microenvironment, whereas their function in glioblastoma chemoresistance is unclear. Herein, we interrogated the correlation between GAFs and chemoresistance of glioblastoma by examining a series of patient-derived GAFs and glioblastoma organoids (GBOs), revealing that GAFs could promote temozolomide resistance in glioblastoma. Mechanistically, C-C motif chemokine ligand 2 (CCL2) secreted by GAFs selectively activated the ERK1/2 signaling in glioblastoma cells to potentiate temozolomide resistance. Pharmacologically disrupting the CCL2-CCR2 axis or MEK1/2-ERK1/2 pathway effectively improved the therapeutic efficacy of temozolomide in GBM cells and patient-derived GBOs, and both decreased phospho-ERK1/2 expression. Collectively, our results identified that targeting the GAF-dominated CCL2-ERK1/2 pathway may be an alternative strategy to alleviate the GAF-mediated chemoresistance of glioblastoma. SignificanceComprehensive interpretation of the mutual support between tumor microenvironment and cancer cells is demanded for glioma with poor response rates to chemotherapy. This study demonstrates that GAFs promote the temozolomide resistance of glioblastoma by secreting cytokine CCL2 to activate ERK1/2 pathway, which may serve as a potential druggable candidate. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/581575v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@167b955org.highwire.dtl.DTLVardef@b892bcorg.highwire.dtl.DTLVardef@1a9b082org.highwire.dtl.DTLVardef@18327a8_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphic abstract.C_FLOATNO Schematic illustration for GAFs mediated chemoresistance of GBMs and underlying mechanisms. We demonstrate that Glioma-associated Fibroblasts (GAFs) grow in gliomas by isolating and identifying a panel of patient-derived GAFs. CCL2 secreted by GAFs stimulates CCR2 in GBM cells, which promotes activation of the ERK1/2 expression to potentiate GBM chemoresistance. C_FIG