同步辐射X荧光研究肝细胞癌组织和癌旁组织微粒体内的金属蛋白分布

用差速离心法提取肝细胞癌组织和癌旁组织的微粒体组分,用等电聚焦(IEF)分离微粒体内的蛋白质,用同步辐射X荧光(SRXRF)测定各蛋白条带内微量元素的含量得到金属蛋白分布信息.结果在肝细胞癌组织以及癌旁组织的微粒体中共检出7个含锰条带、8个含铁条带、6个含铜条带和8个含锌条带.癌组织和癌旁组织微粒体的相应蛋白条带内的金属含量相近,但在癌组织的等电点(pI)为5.9的含铁条带中铁含量仅为癌旁组织相应条带的40%,在pI为93的条带中铜、锌的含量分别是癌旁组织的2倍和35倍.研究结果表明,癌组织和癌旁组织的金属蛋白分布模式明显不同,金属蛋白分布的区别可能与肝组织的癌变相关.

Application of synchrotron radiation X-ray fluorescence to investigating the distribution of metalloproteins in microsome of tumor tissues and nontumor tissues of the liver with hepatoma

The microsome of tumor tissues and their surrounding nontumor tissues of five HCC were prepared with a differential centrifugation procedure. The proteins in cytosol and microsome were separated with the thin layer isoelectric focusing (IEF). The contents of zinc (Zn), iron (Fe), copper (Cu), and manganese (Mn) in protein bands were measured using the synchrotron radiation X-ray fluorescence (SRXRF) analysis. At least 7 Mn-containing bands, 8 Fe-containing bands, 6 Cu-containing bands, and 8 Zn-containing bands in microsome were observed in tumor tissues and their surrounding nontumor tissues for the 5 individuals with HCC. The metal contents in protein bands of tumor tissues were generally similar to those of nontumor tissues, except for bands with pIs of 5.9 and 9.3. The Fe content in the band of 5.9 of tumor microsome was only 40% of that in nontumor, but the Cu and Zn contents are 2- and 3.5-fold higher, respectively, in the band of 9.3 compared to that of nontumor tissues. The results suggest that the metal distribution patterns of various metal-containing bands are distinguishable between the tumor and nontumor tissues. The difference of the metal distribution patterns may be related to the carcinogenesis of the liver tissues.