The intracellular mechanism of alpha-fetoprotein promoting the proliferation of NIH 3T3 cells
The intracellular mechanism of alpha-fetoprotein promoting the proliferation of NIH 3T3 cells
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DOI：
10.1038/sj.cr.7290121
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发表时间：
2002-06-01
期刊：
影响因子：
44.1
通讯作者：
Li, G
中科院分区：
文献类型：
--
作者：
Li, MS;Li, PF;Li, G
目的探讨NIH 3T3细胞表面甲胎蛋白(AFP)受体的存在、性质以及AFP对细胞信号转导通路的影响。方法通过掺入H-3-TdR 来测量AFP 对NIH 3T3 细胞增殖的影响。进行I-125-AFP受体结合测定来检测NIH 3T3细胞中AFP受体的特性。测定了 AFP 对 [cAMP]i 和蛋白激酶 A (PKA) 活性的影响。 Western blot检测K-ras P21蛋白表达的变化。结果0~80 mg/L AFP处理后NIH 3T3细胞增殖能力明显增强。 Scatchard分析表明存在两类结合位点，其K-D分别为2.722x10(-9)M(Bmax=12810个位点/细胞)和8.931x10(-8)M(Bmax=119700个位点/细胞)。在AFP(20 mg/L)存在下，cAMP含量和PKA活性显着升高。 AFP在20 mg/L浓度下上调K-ras P21蛋白水平。抗AFP单克隆抗体可逆转AFP对cAMP含量、PKA活性和K-ras p21基因表达的影响。结论 AFP对细胞增殖的影响是通过与其受体结合，触发cAMP-PKA信号转导通路，改变K-ras p21基因的表达来实现的。
AIM The existence and properties of alpha-fetoprotein (AFP) receptor on the surface of NIH 3T3 cells and the effects of AFP on cellular signal transduction pathway were investigated. METHODS The effect of AFP on the proliferation of NIH 3T3 cells was measured by incorporation of H-3-TdR. Receptor-binding assay of I-125-AFP was performed to detect the properties of AFP receptor in NIH 3T3 cells. The influences of AFP on the [cAMP]i and the activities of protein kinase A (PKA) were determined. Western blot was used to detect the change of K-ras P21 protein expression. RESULTS The proliferation of NIH 3T3 cells treated with 0-80 mg/L of AFP was significantly enhanced. The Scatchard analysis indicated that there were two classes of binding sites with K-D of 2.722x10(-9)M (Bmax=12810 sites per cell) and 8.931x10(-8)M (Bmax=119700 sites per cell) respectively. In the presence of AFP (20 mg/L), the content of cAMP and activities of PKA were significantly elevated. The level of K-ras P21 protein was upregulated by AFP at the concentration of 20 mg/L. The monoclonal antibody against AFP could reverse the effects of AFP on the cAMP content, PKA activity and the expression of K-ras p21 gene. CONCLUSION The effect of AFP on the cell proliferation was achieved by binding its receptor to trigger the signal transduction pathway of cAMP-PKA and alter the expression of K- ras p21 gene.