同步荧光光谱法研究肿瘤芳香族氨基酸残基含量的变化

Study on the Change of the Content of Aromatic Amino Acid Residues in the Process of Malignant Transformation by Synchronous Fluorescence Spectrometry

用同步荧光光谱法评估原发性肝细胞癌患者血浆、肝癌荷瘤小鼠以及培养细胞(HepG2和HL-7702)中酪氨酸(Tyr)和色氨酸(Trp)残基水平变化。固定发射波长λem和激发波长λex之间的波长差Δλ分别为20和60nm,激发和发射单色器同时进行扫描,确定350nm为Trp的同步特征发射峰位置,318nm为Tyr的同步特征发射峰位置。结果表明,肝癌患者及荷瘤小鼠血浆蛋白质所含Tyr和Trp残基的荧光强度明显增加。相反,肝癌细胞或荷瘤小鼠肿瘤组织中Tyr和Trp残基荧光强度却随生长时间增长而减少。进一步实验表明,具有抗癌活性的苦参碱处理癌细胞后,细胞Tyr和Trp残基的荧光强度升高。这些结果表明,Tyr和Trp残基的变化可能参与了肿瘤的发生发展。

Synchronous fluorescence spectra was applied to assess tyrosine（Tyr） and tryptophane（Trp）residues in the plasma of patients suffering hepatocellular carcinoma,tumor-bearing mice, and cultured cells（HepG2 and HL-7702）.The synchronous fluorescence peaks of Tyr and Trp residues were at 318 and 350nm whenΔλ=20nm and Δλ=80nm respectively, and did not shift regardless of the sample variations.The results showed that the fluorescent intensities of Tyr and Trp residues increased significantly in the plasma proteins of patients suffering hepatocellular carcinoma.There was a correlation between the increased fluorescent intensities of murine plasma Tyr or Trp residues and the increasing of time of tumor-bearing,indicating that the alterations of Tyr and Trp residues might be associated with tumor development.On the contrary,the fluorescent intensities of Tyr and Trp residues in tumor tissue or HepG2 cells decreased along with the increasing of time of tumor-bearing or culturing.Further experiments showed that a potential anti-tumor medicine-matrine which exerted an anti-tumor activity could enhance the fluorescence intensities of Tyr and Trp residues.These results demonstrated that synchronous fluorescence spectra could be used to determine Tyr and Trp residues in proteins.By this method,we found that Tyr and Trp residues increased in the plasma proteins of tumor bearing patients and mice which might be correlated with tumor development.On the contrary,Tyr and Trp residues in proteins of tumor tissue or cancer cells decreased.It remains unclear whether these changes acted as a biomarker for protein metabolism imbalance or they contributed to the tumor evolution in malignant diseases,which is worthy of further investigation.