title: The 1p-encoded protein stathmin and resistance of malignant gliomas to nitrosoureas.
abstract: BACKGROUND
  Malignant gliomas are generally resistant to all conventional therapies. Notable exceptions are anaplastic oligodendrogliomas with loss of heterozygosity on chromosome 1p (1p+/-). Patients with 1p+/- anaplastic oligodendroglioma frequently respond to procarbazine, 1-(2-chloroethyl)-3-cyclohexyl-l-nitrosourea, and vincristine. Because the underlying biologic basis for this clinical finding is unclear, we evaluated differentially expressed 1p-encoded proteins in 1p+/- and 1p+/+ malignant glioma cell lines and then examined whether their expression was associated with outcome of patients with anaplastic oligodendroglioma.
  
  
  METHODS
  We used a comparative proteomic screen of A172 (1p+/-) and U251 (1p+/+) malignant glioma cell lines to identify differentially expressed 1p-encoded proteins, including stathmin, a microtubule-associated protein. 1p+/- and 1p+/+ anaplastic oligodendroglioma specimens from 24 patients were assessed for stathmin expression by immunohistochemistry. The relationship between stathmin expression and clinical outcome was assessed with Kaplan-Meier analyses. RNA inhibition and cDNA transfection experiments tested effects of stathmin under- and overexpression, respectively, on the in vitro and in vivo resistance of malignant glioma cells to treatment with nitrosourea. For in vivo resistance studies, 36 mice with intracranial and 16 mice with subcutaneous xenograft tumor implants were used (one tumor per mouse). Flow cytometry was used for cell cycle analysis. Immunoblotting was used to assess protein expression. All statistical tests were two-sided.
  
  
  RESULTS
  Decreased stathmin expression in tumors was statistically significantly associated with loss of heterozygosity in 1p (P<.001) and increased recurrence-free survival (P<.001). The median recurrence-free survival times for patients with tumors expressing low, intermediate, or high stathmin levels were 45 months (95% confidence interval [CI] = 0 to 90 months), 17 months (95% CI = 10.6 to 23.4 months), and 6 months (95% CI = 1.7 to 10.3 months), respectively. Expression of stathmin was inversely associated with overall survival of nitrosourea-treated mice carrying xenograft tumors. Median survival of mice with stathmin+/- tumors was 95 days (95% CI = 68.7 to 121.3 days) and that of mice with stathmin+/+ tumors was 64 days (95% CI = 58.2 to 69.8 days) (difference = 31 days, 95% CI = 4.1 to 57.9 days; P<.001, log-rank test). Nitrosoureas induced mitotic arrest in malignant glioma cells, and this effect was greater in cells with decreased stathmin expression.
  
  
  CONCLUSIONS
  Loss of heterozygosity for the stathmin gene may be associated with improved outcomes of patients with 1p+/- anaplastic oligodendroglioma tumors.
authors: Surgical and Molecular Neuro-oncology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
authors: Teri-T B
authors: TT
authors: Ngo
authors: Tien
authors: T
authors: Peng
authors: Xing-Jie
authors: XJ
authors: Liang
authors: Oluwaseun
authors: O
authors: Akeju
authors: Sandra
authors: S
authors: Pastorino
authors: Wei
authors: W
authors: Zhang
authors: Yuri
authors: Y
authors: Kotliarov
authors: Jean C
authors: JC
authors: Zenklusen
authors: Howard A
authors: HA
authors: Fine
authors: Dragan
authors: D
authors: Maric
authors: Patrick Y
authors: PY
authors: Wen
authors: Umberto
authors: U
authors: De Girolami
authors: Peter McL
authors: PM
authors: Black
authors: Wells W
authors: WW
authors: Wu
authors: Rong-Fong
authors: RF
authors: Shen
authors: Neal O
authors: NO
authors: Jeffries
authors: Dong-Won
authors: DW
authors: Kang
authors: John K
authors: JK
authors: Park
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use; D001483:Base Sequence; D001932:Brain Neoplasms / Q000188:drug therapy / Q000235:genetics*; D045744:Cell Line, Tumor; D002874:Chromosome Mapping; D002878:Chromosomes, Human, Pair 1; D017931:DNA Primers; D004273:DNA, Neoplasm / Q000235:genetics; D019008:Drug Resistance, Neoplasm; D015180:Electrophoresis, Gel, Two-Dimensional; D005910:Glioma / Q000188:drug therapy / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D009607:Nitrosourea Compounds / Q000627:therapeutic use*; D009837:Oligodendroglioma / Q000188:drug therapy / Q000235:genetics*; D012334:RNA, Neoplasm / Q000235:genetics; D050777:Stathmin / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000970:Antineoplastic Agents; D017931:DNA Primers; D004273:DNA, Neoplasm; D009607:Nitrosourea Compounds; D012334:RNA, Neoplasm; D050777:Stathmin