Molecular analysis of flg and its products for targeted therapy on brain tumors

已有研究表明碱性成纤维细胞生长因子（bFGF）在胶质瘤细胞的生长中起重要作用。本研究分析了bFGF受体编码基因fms样基因（fms-like gene，fms）在胶质瘤细胞生长中的生物学活性及其作为恶性胶质瘤治疗靶点的可能性。首先，我们使用RT-PCR技术分析了手术获得的脑肿瘤组织中BMPmRNA的表达。65例脑胶质瘤标本中，胶质瘤组织中BMPmRNA的表达较正常脑组织明显增强。在恶性转化或复发病例中表达进一步增强。组织学上，胶质瘤组织中高细胞性与高表达相关。在此基础上，我们利用Southern和北方杂交技术对培养的胶质母细胞瘤细胞系进行了更详细的分子分析。Southern杂交未发现cDNA扩增，而在北方杂交中表达增强，表明其表达受上游未知转录因子调控。此外，免疫组织化学分析表明，flg-产品被检测到更多的胶质母细胞瘤细胞系比正常的成纤维细胞。反义寡核苷酸在20 μ M浓度下可有效抑制胶质母细胞瘤细胞的生长。所有这些结果表明，FGF-TGF β系统的自分泌或旁分泌环在胶质瘤细胞的增殖中是必不可少的，这也表明TGF β可以作为胶质瘤治疗的一个良好的候选分子靶点。

It has been reported that basic fibroblast growth factor (bFGF) plays an important role in the growth of glioma cells. The gene encoding receptor of bFGF,namely fms-like gene (flg), was analyzed in this study not only to clarify its biological activity in the growth of glioma cells but also to examine its potential to be a molecular target in treatment of malignant gliomas. First we analyzed expression of flg mRNA in brain tumor tissues obtained at surgery using RT-PCR technique. Sixty-five samples were studied, and it was indicated that expression of flg mRNA in glioma tissues were more enhanced than normal brain tissues. Moreover, it's expression was further enhanced in cases with malignant transformation or recurrence. Histopathologically, enchanced flg expression was in correlation with high cellularity in glioma tissues. Based on these facts, we made more detailed molecular analyzes by Southern and Northern blot techniques on cultured glioblastoma cell lines. flg gene amplification was not observed in Southern analysis, while its expression was increased in Northern, indicating its expression should be controlled by upstream unknown transcription factors. In addition, immunohistochemical analyzes indicated that the flg-product was detected more in glioblastoma cell lines than normal fibroblasts. Anti-sense oligo nucleotide effectively suppressed the growth of glioblastoma cells at concentration of 20 muM.All these results indicate that autocrine or paracrine loops of FGF-flg system is essential in glioma cell proliferation, which also indicates that flg can be a good candidate as a molecular target in treatment of gliomas.