Identification of novel molecular players of GBM cell dispersal through an in vitro profiling approach

Abstract

Glioblastoma multiforme (GBM) is the most common and aggressive type of gliomas with a mean survival of 1 year after diagnosis. A major obstacle in treating GBMs is extensive tumor cell infiltration into the surrounding brain. Despite tumor resection and combined therapy, recurrence occurs in the vicinity of the resection margin due to individual cells that dispersed out of the primary tumor, therefore; developing novel therapies that target tumor cell dispersal is of high priority. The goal of this project is to identify genes that are differentially regulated during GBM cell dispersal and to validate their function in in vitro models of dispersal. In this project, we have used an in vitro model of cell motility whereby the dynamics of GBM cell dispersal can be monitored in real-time and quantitated. Accordingly, we isolated motile/migratory/dispersive cells from non-motile/core cells and used these cells for investigating the genes that are differentially regulated during different phases of cell movement by using RNA sequencing. Analysis of the sequencing experiments showed the presence of many differentially expressed genes in motile vs non-motile cells. Most of the genes that have the highest expression in motile cells compared to non-motile ones were linked to epithelial to mesenchymal transition and cell motility based on our pathway and gene set enrichment analyses. Our current focus is on five different candidate genes: CTGF, CYR61, SERPINE1, INHBA and PTX3. Among these, the expression of SERPINE1, a serine protease inhibitor, had predictive value for overall survival of gliomas and therefore is an interesting therapeutic candidate. Currently, we are conducting loss-of-function and gain-of function experiments targeting these genes. Together, these studies have the potential to discover novel molecular players of GBM cell dispersal and open up new avenues for designing new therapeutic strategies against the invasive phenotype of otherwise untreatable malignant GBMs.