Nagamatsu S, Sawa H, Wakizaka A, Hoshino T
Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan.
J Neurochem. 1993 Dec;61(6):2048-53. doi: 10.1111/j.1471-4159.1993.tb07441.x.
The expression of facilitative glucose transporter (GLUT) isoforms in human astrocytic tumors was examined. Reverse transcriptase-polymerase chain reaction of a surgically biopsied glioblastoma was carried out using the degenerative oligonucleotide primers corresponding to the sequences of the human facilitative glucose transporter family, and polymerase chain reaction products were hybridized with human GLUT1, GLUT2, GLUT3, GLUT4, and GLUT5 cDNA probes. The results showed that a biopsied glioblastoma expressed GLUT1, GLUT3, and GLUT4 glucose transporter genes. Northern blot analysis of total RNA (10 micrograms) from a biopsied glioblastoma showed the transcripts of only GLUT1 and GLUT3, suggesting that the expression of insulin-responsive glucose transporter GLUT4 mRNA is relatively low. Immunoblot analysis of biopsied glioblastoma tissues by polyclonal antibodies against the C-terminal synthetic peptides of GLUT1, GLUT3, and GLUT4 showed a single band of each polypeptide. However, elevated expression of GLUT1 and GLUT3 glucose transporters was not observed in the glioblastoma. Astrocytic tumor tissues (n = 14) were also examined immunohistochemically. Reactive products for GLUT1 were observed in the luminal surface of capillaries in all cases, whereas tumor cells were positive for GLUT1 in only two of 14 cases. GLUT3 was positive in astrocytic tumor cells in all cases. Three of 14 cases expressed the GLUT4 protein, which was localized in the cytoplasm of tumor cells. These results suggest that the facilitative glucose transport may be altered in astrocytic tumor cells and thus display a significant change in glucose metabolism.
研究了人星形细胞瘤中易化葡萄糖转运体（GLUT）亚型的表达情况。使用与人易化葡萄糖转运体家族序列相对应的简并寡核苷酸引物，对手术活检的胶质母细胞瘤进行逆转录聚合酶链反应，并将聚合酶链反应产物与人GLUT1、GLUT2、GLUT3、GLUT4和GLUT5 cDNA探针杂交。结果显示，活检的胶质母细胞瘤表达GLUT1、GLUT3和GLUT4葡萄糖转运体基因。对活检的胶质母细胞瘤的总RNA（10微克）进行Northern印迹分析，结果显示只有GLUT1和GLUT3的转录本，提示胰岛素反应性葡萄糖转运体GLUT4 mRNA的表达相对较低。用针对GLUT1、GLUT3和GLUT4 C端合成肽的多克隆抗体对活检的胶质母细胞瘤组织进行免疫印迹分析，结果显示每种多肽均有一条单带。然而，在胶质母细胞瘤中未观察到GLUT1和GLUT3葡萄糖转运体的表达升高。还对14例星形细胞瘤组织进行了免疫组织化学检查。所有病例中均在毛细血管腔表面观察到GLUT1的反应产物，而在14例病例中只有2例肿瘤细胞GLUT1呈阳性。所有病例中星形细胞瘤细胞GLUT3均呈阳性。14例病例中有3例表达GLUT4蛋白，其定位于肿瘤细胞的细胞质中。这些结果提示，星形细胞瘤细胞中易化葡萄糖转运可能发生改变，从而在葡萄糖代谢方面表现出显著变化。
