NEO212 Inhibits Migration and Invasion of Glioma Stem Cells

Abstract

Glioblastoma multiforme is a malignant brain tumor noted for its extensive vascularity, aggressiveness, and highly invasive nature, suggesting that cell migration plays an important role in tumor progression. The poor prognosis in GBM is associated with a high rate of tumor recurrence, and resistance to the standard of care chemotherapy, temozolomide (TMZ). The novel compound NEO212, a conjugate of TMZ and perillyl alcohol (POH), has proven to be 10-fold more cytotoxic to glioma stem cells (GSC) than TMZ, and is active against TMZ-resistant tumor cells. In this study, we show that NEO212 decreases migration and invasion of primary cultures of patient-derived GSCs, in both mesenchymal USC02 and proneural USC04 populations. The mechanism by which NEO212 reduces migration and invasion appears to be independent of its DNA alkylating effects, which cause cytotoxicity during the first hours of treatment, and is associated with a decrease in the FAK/Src signaling pathway, an effect not exhibited by TMZ. NEO212 also decreases the production of matrix metalloproteinases MMP2 and MMP9, crucial for GSC invasion. Gene expression analysis of epithelial and mesenchymal markers suggests that NEO212 increases the expression of epithelial-like characteristics, suggesting a reversion of the epithelial-to-mesenchymal transition process. Furthermore, in an orthotopic glioma model, NEO212 decreases tumor progression by reducing invasion of GSCs, thereby increasing survival time of mice. These studies indicate that NEO212, in addition to cytotoxicity, can effectively reduce migration and invasion in GSCs, thus exhibiting significant clinical value in the reduction of invasion and malignant glioma progression..

MiR-18a-downregulated RORA inhibits the proliferation and tumorigenesis of glioma using the TNF-α-mediated NF-κB signaling pathway

“…Theories underlying glioma evolution, treatment resistance, and recurrence support the existence and key roles of glioma stem cells (GSCs) [5]. Our study of disordered genes in GSCs may therefore provide possible treatment targets for glioma molecular therapy [6].…”

NEO212: sub-cytotoxic doses capable of inhibiting glioma stem cell invasion

“…GBM cells often acquire resistance to TMZ through mutations in the DNA repair mechanisms such as the base excision repair (BER), poly(ADP-ribose) polymerase (PARP), mismatch repair (MMR), and especially, through the overexpression of the repair enzyme O 6 -methyl-guanine-DNA methyltransferase (MGMT) [ 2 ]. One of the main causes for tumor recurrence is a small sub-population of TMZ-resistant glioma stem cells (GSC), with capacity for self-renewal and in vivo tumor initiation [ 3 , 4 ].…”

“…We have recently reported that NEO212 also decreases migration and invasion of several patient-derived GSC to a greater extent than TMZ and/or POH, through a mechanism independent of its DNA alkylating effects [ 2 ]. TMZ loses its cytotoxicity after 2 h when incubated in cell-free medium at 37°C, while NEO212 loses it after 24 h [ 8 ].…”

“…This reduction in migration and invasion is likely associated with the decreased activation of the FAK/Src signaling pathway, as shown by a reduced phosphorylation levels of FAK, Src, and the downstream kinases AKT, MEK1/2 and p38-MAPK, as well as in the matrix metalloproteinases MMP2 and MMP9. This mechanism of action differs from that of TMZ, which at equipotent concentrations causes a non-specific blockade in the protein synthesis [ 2 ]. These studies suggest that the mechanisms of action of both drugs are different, and that NEO212 acts as a multi-target drug, potentially resulting in improved anti-tumor efficacy and lower risk of drug resistance and tumor recurrence.…”

“…FAK/Src route regulates the EMT process, a prerequisite for cell migration, invasion, and metastasis. Gene expression analysis of epithelial and mesenchymal markers suggest that NEO212 reverts the epithelial-to-mesenchymal transition (EMT) process, mainly by upregulating several genes commonly downregulated during EMT [ 2 ].…”