ApoF低表达提示肝癌患者预后不良

背景:肝癌患者常伴有代谢异常。越来越多的证据表明,脂质代谢在肝癌进展中具有至关重要的作用。载脂蛋白F(ApoF)是一种脂质转运蛋白抑制剂,其在肝癌中的作用并不十分明了。本研究旨在评价ApoF在肝癌中的作用。方法:采用定量逆转录聚合酶链反应(qRT-PCR)方法检测肝癌组织和肝癌细胞(SMMC-7721、HepG2和Huh7)中ApoF mMRA的表达。采用免疫组化技术检测肝癌组织中ApoF蛋白表达,并分析其与肝癌患者临床病理特征及预后的关系。最后,分别在体外(SMMC-7721和Huh7肝癌细胞系)和体内试验(异种移植裸鼠模型)中检测ApoF对肝癌生长的影响。结果:无论是在mRNA还是蛋白水平,ApoF在肝癌组织中的表达都显著下调。在smmc-7721和Huh7肝癌细胞中,ApoF过表达可抑制肝癌细胞的增殖和迁移。在异种移植裸鼠模型中,ApoF过表达可有效抑制肝癌的生长。Kaplan-Meier分析结果显示,ApoF低表达的肝癌患者无复发生存率明显低于ApoF高表达者。ApoF低表达与肝硬化、巴塞罗那临床肝癌分期及TNM分期等临床病理特征显著相关。结论:ApoF在肝癌中表达下调,而其低表达提示无复发生存率不佳。作为一种肝癌抑制因子,ApoF可能成为一个潜在的肝癌治疗靶点。

Characterization of Interspecific Hybrids Between Oryza sativa L, and Three Wild Rice Species of China by Genomic In Situ Hybridization

In the genus Oryza, interspecific hybrids are useful bridges for transferring the desired genes from wild species to cultivated rice （Oryza sativa L.）. In the present study, hybrids between O. sativa （AA genome） and three Chinese wild rices, namely O. rufipogon （AA genome）, O. officinalis （CC genome）, and O. meyeriana （GG genome）, were produced. Agricultural traits of the F1 hybrids surveyed were intermediate between their parents and appreciably resembled wild rice parents. Except for the O. sativa × O. rufipogon hybrid, the other F1 hybrids were completely sterile. Genomic in situ hybridization （GISH） was used for hybrid verification. Wild rice genomic DNAs were used as probes and cultivated rice DNA was used as a block. With the exception of O. rufipogon chromosomes, this method distinguished the other two wild rice and cultivated rice chromosomes at the stage of mitotic metaphase with different blocking ratios. The results suggest that a more distant phylogenetic relationship exists between O. meyeriana and O. sativa and that O. rufipogon and O. sativa share a high degree of sequence homology. The average mitotic chromosome length of O. officinalis and O. meyeriana was 1.25- and 1.51-fold that of O. sativa, respectively. 4＇,6＇-Diamidino- 2-phenylindole staining showed that the chromosomes of O. officinalis and O. meyeriana harbored more heterochromatin, suggesting that the C and G genomes were amplified with repetitive sequences compared with the A genome. Although chromocenters formed by chromatin compaction were detected with wild rice-specific signals corresponding to the C and G genomes in discrete domains of the F1 hybrid interphase nuclei, the size and number of O. meyeriana chromocenters were bigger and greater than those of O. officinalis. The present results provide an important understanding of the genomic relationships and a tool for the transfer of useful genes from three native wild rice species in China to cultivars.

Heterozygosity of Knob-Associated Tandem Repeats and Knob Instability in Mitotic Chromosomes of Zea （Zea mays L. and Z. diploperennis Iltis Doebley）

Knobs are blocks of heterochromatin present on chromosomes of maize （Zea mays L.） and its relatives that have effects on the frequency of genetic recombination, as well as on chromosome behavior. Knob heterozygosity and instability in six maize inbred lines and one Z. diploperennis Iltis Doebley line were investigated using the fluorescence in situ hybridization （FISH） technique with knob-associated tandem repeats （180 bp and 350 bp （TR- 1）） as probes. Signals of seven heterozygous knobs containing 180- bp repeats and of one heterozygous knob containing TR- 1 were captured in chromosomes of all materials tested according to the results of FISH, which demonstrates that the 180-bp repeat is the main contributor to knob heterozygosity compared with the TR- 1 element. In addition, one target cell with two TR- 1 signals on one homolog of chromosome 2L, which was different from the normal cells in the maize inbred line GB57, was observed, suggesting knob duplication and an instability phenomenon in the maize genome.