A selective splicing variant of hepcidin mRNA in hepatocellular carcinoma cell lines.
A selective splicing variant of hepcidin mRNA in hepatocellular carcinoma cell lines.
复制标题
肝细胞癌细胞系中铁调素 mRNA 的选择性剪接变体。
DOI：
10.1016/j.bbrc.2016.05.153
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Kohgo Y.
中科院分区：
文献类型：
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作者：
Toki Y;Sasaki K;Tanaka H;Yamamoto M;Hatayama M;Ito S;Ikuta K;Shindo M;Hasebe T; Nakajima S;Sawada K;Fujiya M;Torimoto Y;Ohtake T;Kohgo Y.
海普西丁是铁代谢的主要调节因子，其异常表达通过与铁蛋白相互作用影响肠道对铁的吸收和网状内皮隔离。还指出，铁的异常积聚是促进包括肝癌在内的癌症发生和发展的关键因素之一。RT-PCR/琼脂糖凝胶电泳法检测肝癌细胞株HLF中的海普西丁mRNA，除野生型海普西丁外，还可见一条较小的条带。序列分析表明，这条带是HAMP基因外显子2缺失的海普西丁基因的选择性剪接变异体，产生编码前海普西丁中间缺失20个氨基酸的截短肽的转录本。在本研究中，我们使用的是数字聚合酶链式反应，因为这样少量的变异mRNA很难用常规的RT-PCR扩增来定量。在7个肝癌细胞系中，有6个细胞系具有显著的该变异基因拷贝数，但没有一个细胞系具有显著的拷贝数。在瞬时转染法中，截短的前肝素与天然的前肝素相比具有不同的特点：其产物对消化不敏感，并以完整的前肝素形式分泌到培养基内，不成熟。通过异常剪接使HAMP基因功能丧失或降低，可能是获得肝癌细胞增殖优势的一种合适现象。
Hepcidin is a main regulator of iron metabolism, of which abnormal expression affects intestinal absorption and reticuloendothelial sequestration of iron by interacting with ferroportin. It is also noted that abnormal iron accumulation is one of the key factors to facilitate promotion and progression of cancer including hepatoma. By RT-PCR/agarose gel electrophoresis of hepcidin mRNA in a hepatocellular carcinoma cell line HLF, a smaller mRNA band was shown in addition to the wild-type hepcidin mRNA. From sequencing analysis, this additional band was a selective splicing variant of hepcidin mRNA lacking exon 2 ofHAMPgene, producing the transcript that encodes truncated peptide lacking 20 amino acids at the middle of preprohepcidin. In the present study, we used the digital PCR, because such a small amount of variant mRNA was difficult to quantitate by the conventional RT-PCR amplification. Among seven hepatoma-derived cell lines, six cell lines have significant copy numbers of this variant mRNA, but not in one cell line. In the transient transfection analysis of variant-type hepcidin cDNA, truncated preprohepcidin has a different character comparing with native preprohepcidin: its product is insensitive to digestion, and secreted into the medium as a whole preprohepcidin form without maturation. Loss or reduction of function ofHAMPgene by aberrantly splicing may be a suitable phenomenon to obtain the proliferating advantage of hepatoma cells.