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Combined BH3 and Metabolic Profiling as a Method to Define Therapeutic Response and Resistance in Grade IV Astrocytomas
Author(s) -
Silva Monica Rodriguez,
GonzalezArias Sergio,
Chambers Jeremy W.
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1100.6
Subject(s) - u87 , temozolomide , cancer research , cell culture , western blot , apoptosis , viability assay , medicine , glioma , chemistry , biology , biochemistry , genetics , gene
Background and Significance 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‐derived cell lines 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 GBM cell lines from the NCI60 bank (SF268, SF295, SF539, SNB19, SNB75 and U251) 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 IC 50 values for temozolomide (TMZ). Results Western blot analysis of pro‐survival and pro‐apoptotic Bcl‐2 proteins revealed that U118, U87 and SNB19 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 (Bid, Bim, Puma, etc.) levels were increased in H4 and A172 when compared to the U118 and U87 cell lines. Metabolic analysis of the cell lines revealed that U118 and SF295 cells were glutaminolytic, while U87, A172, and H4 were classified as glycolytic. We assessed cellular viability in the presence of increasing doses of TMZ for each cell line. We found that U118 and SNB19 cells were the most resistant followed by U87, SF295, U251, A172, SF539, SF268, SNB75 and H4 respectively. Interestingly, MGMT levels did not influence chemo‐responsiveness in these cell lines. Conclusion We found that Bcl‐2 protein profiling was a useful means to determine therapeutic response and resistance. This was further enhanced by metabolic stratification, wherein glycolytic cells were shown to be more sensitive TMZ than glutaminolytic cells that may possess more stable mitochondria. In the immediate future, we will increase the cellular profiling to include mitochondrial dynamics and quality control as well. Using these approaches, we will produce a method to define GBM responses and outcomes based on their mitochondrial and metabolic context. Support or Funding Information M.R.S. was supported by NIH/NIGMS R25 GM061347. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.