BCNU down-regulates anti-apoptotic proteins bcl-xL and Bcl-2 in association with cell death in oligodendroglioma-derived cells.
Oligodendroglial differentiation in gliomas is associated with enhanced sensitivity to chemotherapy. Antiapoptotic proteins, Bcl-xL and Bcl-2, are over-expressed in early passage cell lines derived from glioblastomas. Down-regulation of Bcl-xL and Bcl-2 with DNA antisense oligonucleotides promotes cell death in glioblastoma cells. Changes of expression of Bcl-xL and Bcl-2 after chemotherapy treatment have not been studied in glioma subtypes. The current experiments correlate decreased expression of both Bcl-xL and Bcl-2 after BCNU chemotherapy and cell death in two oligodendroglioma-derived cell lines. Expression of Bcl-2 family member proteins Bcl-xL, Bcl-2, and Bax were assessed in glioma cells both before and after chemotherapy treatment. Cell survival was assessed with a crystal violet bioassay. Levels of expression of Bcl-2 and Bcl-xL were elevated in two early passage oligodendroglioma-derived cell lines compared with a non-neoplastic glial cell line. BCNU chemotherapy markedly down-regulated expression of Bcl-xL and Bcl-2 proteins in both oligodendroglioma-derived cell lines. Changes in expression of Bcl-xL and Bcl-2 were associated with the increased sensitivity to chemotherapy. There were no changes noted in expression of Bax after BCNU treatment. Modulation of expression of the anti-apoptotic proteins, Bcl-xL and Bcl-2, in the two oligodendroglioma-derived cell lines was associated with increased sensitivity to BCNU chemotherapy. Down-regulation of Bcl-xL and Bcl-2 resulted in reversal of the ratio of Bax/Bcl-xL and Bax/Bcl-2 and enhanced cell death after treatment with BCNU. Mechanisms that control expression of the anti-apoptotic proteins Bcl-xL and/or Bcl-2 may be effective targets in treatment strategies in patients with malignant gliomas.
Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, USA.
Richard A
RA
Lytle
Zhihong
Z
Jiang
Xiao
X
Zheng
Keith M
KM
Rich
D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D001932:Brain Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D002330:Carmustine / Q000494:pharmacology* / Q000627:therapeutic use; D045744:Cell Line, Tumor; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D009457:Neuroglia / Q000187:drug effects / Q000502:physiology; D009837:Oligodendroglioma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
D018906:Antineoplastic Agents, Alkylating; C494826:BAX protein, human; C494811:BCL2L1 protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D002330:Carmustine