Phosphorothioate antisense oligonucleotides against basic fibroblast growth factor inhibit anchorage-dependent and anchorage-independent growth of a malignant glioblastoma cell line.

Abstract

Basic fibroblast growth factor (bFGF) is a broad spectrum mitogen for many cells of neuroectodermal origin, including glial cells. The human malignant glioblastoma cell line U87-MG expresses high steady state levels of the bFGF mRNA and contains abundant stores of biologically active bFGF protein. In the present study we have examined the contribution of endogenous bFGF to the autocrine growth of these cells. Using reverse transcription-polymerase chain reaction, U87-MG cells were shown to express the mRNAs for both bFGF and the bFGF receptor, confirming the existence of the basic requirements for an autocrine loop. Addition of 5 microM bFGF-specific antisense oligonucleotide to U87-MG cultures significantly inhibited the growth rate of these cells within 48 h and blocked proliferation beyond 2 days. The corresponding bFGF-specific sense oligonucleotide did not significantly inhibit cell proliferation over the course of these experiments. Similarly, antisense oligonucleotides significantly inhibited colony formation in soft agar, while the sense sequence was without effect. Western blotting with antihuman bFGF revealed that U87-MG cells synthesize three isoforms of bFGF, approximately 18, 23, and 25 kilodaltons (kDa) in size. The 23- and 25-kDa isoforms together comprise approximately 80% of the total cellular stores of bFGF. Antisense treatment for 4 days reduced the abundance of the 23- and 25-kDa isoforms by 64-74%, but had little effect on the 18-kDa isoform. The inhibitory effect of the antisense oligonucleotides on anchorage-dependent proliferation was reversed by the addition of recombinant 18-kDa human bFGF.(ABSTRACT TRUNCATED AT 250 WORDS)

Basic fibroblast growth factor transcriptional autoregulation requires EGR-1

“…Recently, it was shown that a neutralizing antibody to bFGF bFGF autoregulation requires Egr-1 D Wang et al blocked the in vivo tumor growth and angiogenesis of U87MG (Stan et al, 1995), indicating a function for secreted bFGF and suggesting that bFGF may play a critical role in the growth of these cells. Consistent with this observation are the results of Murphy et al (1992) who showed that antisense to bFGF blocked anchorage-independent growth of the U87MG cell line. Our data presented here indicate that a critical downstream e ector of bFGF function is the Egr-1 transcription factor.…”

Basic Fibroblast Growth Factor (FGF-2) Overexpression Is a Risk Factor for Esophageal Cancer Recurrence and Reduced Survival, which Is Ameliorated by Coexpression of the FGF-2 Antisense Gene

“…Ectopic expression of FGF-2 has been shown previously to transform normal cells into a malignant phenotype (27), and inhibition of FGF-2 expression with antisense oligonucleotides can reverse the transformed phenotype (28). The endogenous antisense RNA (FGF-AS) has been implicated in the posttranscriptional regulation of FGF-2 expression (11), but its possible role in tumor progression has not been investigated previously.…”

Farnesyltransferase inhibitor, R115777, reverses the resistance of human glioma cell lines to ionizing radiation

“…1 EGFR amplification has been found in half of the GBM. 2 Expression of other growth factors, including fibroblast growth factor 3,4 and vascular endothelial growth factor, 5 has also been observed in human glioma. These abnormal patterns of expression may be related to an activation of Ras pathways.…”