Wang Q, Maloof P, Wang H, Fenig E, Stein D, Nichols G, Denny T N, Yahalom J, Wieder R
Department of Medicine, UMDNJ-New Jersey Medical School, Newark 07103 USA.
Exp Cell Res. 1998 Jan 10;238(1):177-87. doi: 10.1006/excr.1997.3820.
Basic fibroblast growth factor (bFGF) is a mitogen and a survival factor in fibroblasts and endothelial cells. It acts as an angiogenesis factor in breast cancer, but paradoxically inhibits proliferation in several breast cancer cell lines. In this study, we investigated the effects of bFGF on the survival of MCF-7 human breast cancer cells in order to determine if these effects were also opposite to those in fibroblasts. Incubation of NIH 3T3 cells with bFGF for 24 h caused an approximately 30% increase in day 12 +/- 2 adherent colonies while causing an approximately 50% decrease in MCF-7 colony formation. Incubation of NIH 3T3 cells with bFGF prior to etoposide or 5-fluorouracil treatment caused a proportionally smaller decrease in colony forming efficiency as a result of drug treatment, while preincubation of MCF-7 cells with bFGF caused a similar but opposite additive increase in drug-induced diminution of colony forming efficiency. These effects on MCF-7 cells were observed at variable times of incubation and doses of etoposide to 1 microM and 5-fluorouracil to 200 microM and at variable times of incubation and concentrations of bFGF to 1 ng/ml. Incubating with bFGF after drug exposure had similar effects on the reduction of cloning efficiency. The effects of bFGF were similar on programmed cell death, as determined by morphologic characteristics of apoptosis on 400 cell counts and FITC-dUTP 3'-OH DNA end labeling. Basic FGF promoted apoptosis and increased the rate of drug-induced cell death with both etoposide and 5-fluorouracil. While recombinant bFGF affected Bcl-2 protein and mRNA levels in NIH 3T3 cells only marginally and variably and had no discernible effects on Bax protein levels, it markedly downregulated Bcl-2 mRNA and protein levels in MCF-7 cells and caused an increase in Bax protein levels. These changes resulted in a decreased association of Bcl-2 with immunoprecipitable Bax and an increased association of Bax with immunoprecipitable Bcl-2 in MCF-7 cells treated with bFGF. These data suggest that bFGF may cause different phenotypic responses in breast cancer cells from those in surrounding cells and offer one possible mechanism through opposite regulation of Bcl-2 and Bax. Inhibition of colony formation by bFGF was observed in several breast cancer cells lines, demonstrating that this effect demonstrated in MCF-7 cells was more universal.
碱性成纤维细胞生长因子（bFGF）是成纤维细胞和内皮细胞中的一种促有丝分裂因子和存活因子。它在乳腺癌中作为一种血管生成因子起作用，但矛盾的是，它在几种乳腺癌细胞系中抑制增殖。在本研究中，我们研究了bFGF对MCF-7人乳腺癌细胞存活的影响，以确定这些影响是否也与对成纤维细胞的影响相反。用bFGF孵育NIH 3T3细胞24小时，导致第12天±2天贴壁集落增加约30%，而MCF-7集落形成减少约50%。在依托泊苷或5-氟尿嘧啶处理前用bFGF孵育NIH 3T3细胞，由于药物处理，集落形成效率的降低比例较小，而用bFGF预孵育MCF-7细胞，药物诱导的集落形成效率降低有类似但相反的累加增加。在不同的孵育时间和依托泊苷剂量至1 microM以及5-氟尿嘧啶剂量至200 microM时，以及在不同的孵育时间和bFGF浓度至1 ng/ml时，均观察到对MCF-7细胞的这些影响。药物暴露后用bFGF孵育对克隆效率的降低有类似影响。bFGF对程序性细胞死亡的影响相似，这通过对400个细胞计数的凋亡形态学特征和FITC-dUTP 3'-OH DNA末端标记来确定。碱性FGF促进凋亡并增加依托泊苷和5-氟尿嘧啶诱导的细胞死亡速率。虽然重组bFGF对NIH 3T3细胞中Bcl-2蛋白和mRNA水平的影响仅轻微且多变，对Bax蛋白水平无明显影响，但它显著下调MCF-7细胞中Bcl-2 mRNA和蛋白水平，并导致Bax蛋白水平增加。这些变化导致在bFGF处理的MCF-7细胞中，Bcl-2与可免疫沉淀的Bax的结合减少，而Bax与可免疫沉淀的Bcl-2的结合增加。这些数据表明，bFGF在乳腺癌细胞中可能引起与周围细胞不同的表型反应，并通过对Bcl-2和Bax的相反调节提供了一种可能的机制。在几种乳腺癌细胞系中观察到bFGF对集落形成的抑制作用，表明在MCF-7细胞中证明的这种作用更具普遍性。
