Canute G W, Longo S L, Longo J A, Winfield J A, Nevaldine B H, Hahn P J
Department of Neurosurgery, State University of New York Health Science Center, Syracuse, USA.
Neurosurgery. 1996 Nov;39(5):976-83. doi: 10.1097/00006123-199611000-00019.
We sought to determine whether hydroxyurea could accelerate the loss of amplified epidermal growth factor receptor (EGFR) genes from glioblastoma multiforme (GBM). There is good reason to think that elimination of amplified EGFR genes from GBMs will negatively impact tumor growth. Hydroxyurea has previously been shown to induce the loss of amplified genes from extrachromosomal double minutes (dmin) but not from chromosomal homogeneously staining regions.
Pulsed-field gel electrophoresis and Southern blot hybridization were used to demonstrate EGFR genes amplified as dmin. Giemsa-stained metaphase spreads were prepared in an attempt to visualize dmin. A GBM cell line containing amplified EGFR genes was treated continuously in vitro with 0 to 150 mumol/L hydroxyurea, and slot blot analysis was used to show the loss of amplified EGFR genes.
Amplified EGFR genes were found on dmin in 4 of 11 (36%) fresh human GBM biopsy specimens. None of the GBMs contained EGFR genes amplified as homogeneously staining regions. Amplified dmin were not microscopically visible when stained with Giemsa because of their small size. Slot blot analysis showed that these low doses of hydroxyurea accelerated the loss of amplified EGFR genes in a dose- and time-dependent fashion. Pulsed-field gel electrophoresis and Southern blot analysis confirmed that EGFR gene loss was accompanied by amplified dmin loss in a dose-dependent fashion.
These studies suggest the potential use of low-dose hydroxyurea in the treatment of GBMs.
我们试图确定羟基脲是否能加速多形性胶质母细胞瘤（GBM）中扩增的表皮生长因子受体（EGFR）基因的丢失。有充分理由认为，从GBM中消除扩增的EGFR基因将对肿瘤生长产生负面影响。此前已证明羟基脲可诱导染色体外双微体（dmin）上扩增基因的丢失，但不能诱导染色体均匀染色区上扩增基因的丢失。
采用脉冲场凝胶电泳和Southern印迹杂交来证明EGFR基因作为dmin被扩增。制备吉姆萨染色的中期染色体铺片，试图观察dmin。用0至150μmol/L的羟基脲对含有扩增EGFR基因的GBM细胞系进行体外连续处理，并用狭缝印迹分析来显示扩增的EGFR基因的丢失。
在11份新鲜人类GBM活检标本中的4份（36%）中，发现dmin上存在扩增的EGFR基因。没有GBM含有作为均匀染色区扩增的EGFR基因。由于dmin体积小，吉姆萨染色后在显微镜下不可见。狭缝印迹分析表明，这些低剂量的羟基脲以剂量和时间依赖性方式加速了扩增的EGFR基因的丢失。脉冲场凝胶电泳和Southern印迹分析证实，EGFR基因的丢失与dmin扩增的丢失呈剂量依赖性。
这些研究表明低剂量羟基脲在GBM治疗中的潜在用途。
