CBIO-07COMBINED BH3 AND METABOLIC PROFILING AS A METHOD TO DEFINE THERAPEUTIC RESPONSE AND RESISTANCE IN GRADE IV ASTROCYTOMAS

Abstract

BACKGROUND: Grade IV astrocytomas, formerly known as glioblastoma multiforme (GBM), are the most common primary brain tumors and have the highest mortality. The therapeutic standard for managing this malignancy remains a combination of surgery, chemotherapy, and radiotherapy; however, there is no cure, nor has there been any significant advancement in the clinical approach to GBM since this protocol was established in 2005. This study aims to better understand the molecular and metabolic characteristics of GBM to better define treatment groups and potentially identify new avenues for therapy. This study utilized continuous, commercially-available GBM cell lines U87, U118, A172, and H4, and examined the concentrations of Bcl-2 family proteins on mitochondria and metabolic activity for each of the cell lines. The measures were correlated to temozolamide (TMZ) sensitivity. RESULTS: Western blot analysis of pro-survival and pro-apoptotic Bcl-2 proteins revealed that U118 and U87 expressed high levels of Bcl-2, while A172 had increased Bcl-xL expression. Interestingly, Bcl-2 and Bcl-xL were not detected in H4 cells. Incidentally, pro-apoptotic BH3-only protein levels were increased in H4 and A172 cells. Metabolic analysis of the cell lines revealed that U118 cells were a glutaminolytic, while U87, A172, and H4 were classified as glycolytic. We found that U118 cells were the most resistant followed by U87, A172, and H4, respectively. CONCLUSIONS: We found that Bcl-2 protein profiling was a useful means to determine therapeutic response and resistance. This was enhanced by addingmetabolic stratification, wherein glycolytic cells were shown to be more sensitive TMZ than glutaminolytic cells. We will expand the number of cell lines in our study and increase the cellular profiling to include mitochondrial dynamics. Using this approach, we will produce a method to define GBM responses and outcomes based on the mitochondrial and metabolic context of individual tumors.