ET-06 Suppression of glioblastoma through novel drug based on “Gene Switch Technology”

Glioblastoma (GBM) is the most common and aggressive malignancy primarily affecting adults. Despite intensive multimodal therapies, the prognosis of GBM is dismal and a novel therapy is needed. Here, we focused on RUNX, a transcription factor involved in the malignant transformation of GBM, and developed a novel Chlorambucil-conjugated PI-polyamides (Chb-M’), which “switches off” RUNX family. Chb-M’ specifically recognizes the consensus RUNX-binding sequences (TGTGGT) and alkylates it to inhibit transcription of the downstream gene of RUNX family. Chb-M’ has been shown to induce apoptosis and suppress proliferation in a variety of cancers including leukemia, and in this study, similar results were found for glioblastoma cells in vitro. Specific inhibition of RUNX1 led to a marked inhibition of tumor growth through cell cycle arrest and apoptosis. By using apoptosis array, we isolated several candidate genes which regulated by RUNX1. And some types of glioblastoma cell lines treated with Chb-M’ showed elevated expression of p21 and decreased survivin. From in silico analysis using glioma patient cohorts, survivin expression was significantly higher in GBM and it was possibly involved in maintaining the malignancy of GBM. Mechanistically survivin was found to be directly transcriptionally regulated by RUNX1 through ChIP assay and reporter assay. In addition, survivin K/D cells upregulated p21 expression and accelerated apoptosis. Taken together, we hypothesized that the RUNX1-survivin-p21 pathway can potentially be exploited in the management of this malignancy. Chb-M’ mediated regulation of RUNX1 can be a novel therapeutic strategy against GBM.