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Title: A selective splicing variant of hepcidin mRNA in hepatocellular carcinoma cell lines

Abstract

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 of HAMP gene, 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 functionmore » of HAMP gene by aberrantly splicing may be a suitable phenomenon to obtain the proliferating advantage of hepatoma cells. - Highlights: • An aberrant splicing variant of hepcidin mRNA lacking exon 2 of HAMP gene. • Absolute quantification of hepcidin mRNA by digital PCR amplification. • Hepatoma-derived cell lines have significant copies of variant-type hepcidin mRNA. • Truncated preprohepcidin is secreted from cells without posttranslational cleavage.« less

Authors:
 [1];  [2];  [3]; ; ; ; ; ; ; ; ;  [1];  [4]; ;  [5]
  1. Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Hokkaido 078-8510 (Japan)
  2. Department of Gastrointestinal Immunology and Regenerative Medicine, Asahikawa Medical University, Hokkaido 078-8510 (Japan)
  3. Department of Legal Medicine, Asahikawa Medical University, Hokkaido 078-8510 (Japan)
  4. Oncology Center, Asahikawa Medical University Hospital, Hokkaido 078-8510 (Japan)
  5. Department of Gastroenterology, International University of Health and Welfare Hospital, Tochigi 329-2763 (Japan)
Publication Date:
OSTI Identifier:
22606135
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 476; Journal Issue: 4; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; AMINO ACIDS; ELECTROPHORESIS; EXONS; GENES; HEPATOMAS; INTESTINAL ABSORPTION; IRON; MESSENGER-RNA; METABOLISM; POLYMERASE CHAIN REACTION; SPLICING

Citation Formats

Toki, Yasumichi, Sasaki, Katsunori, E-mail: k-sasaki@asahikawa-med.ac.jp, Tanaka, Hiroki, Yamamoto, Masayo, Hatayama, Mayumi, Ito, Satoshi, Ikuta, Katsuya, Shindo, Motohiro, Hasebe, Takumu, Nakajima, Shunsuke, Sawada, Koji, Fujiya, Mikihiro, Torimoto, Yoshihiro, Ohtake, Takaaki, and Kohgo, Yutaka. A selective splicing variant of hepcidin mRNA in hepatocellular carcinoma cell lines. United States: N. p., 2016. Web. doi:10.1016/J.BBRC.2016.05.153.
Toki, Yasumichi, Sasaki, Katsunori, E-mail: k-sasaki@asahikawa-med.ac.jp, Tanaka, Hiroki, Yamamoto, Masayo, Hatayama, Mayumi, Ito, Satoshi, Ikuta, Katsuya, Shindo, Motohiro, Hasebe, Takumu, Nakajima, Shunsuke, Sawada, Koji, Fujiya, Mikihiro, Torimoto, Yoshihiro, Ohtake, Takaaki, & Kohgo, Yutaka. A selective splicing variant of hepcidin mRNA in hepatocellular carcinoma cell lines. United States. doi:10.1016/J.BBRC.2016.05.153.
Toki, Yasumichi, Sasaki, Katsunori, E-mail: k-sasaki@asahikawa-med.ac.jp, Tanaka, Hiroki, Yamamoto, Masayo, Hatayama, Mayumi, Ito, Satoshi, Ikuta, Katsuya, Shindo, Motohiro, Hasebe, Takumu, Nakajima, Shunsuke, Sawada, Koji, Fujiya, Mikihiro, Torimoto, Yoshihiro, Ohtake, Takaaki, and Kohgo, Yutaka. Fri . "A selective splicing variant of hepcidin mRNA in hepatocellular carcinoma cell lines". United States. doi:10.1016/J.BBRC.2016.05.153.
@article{osti_22606135,
title = {A selective splicing variant of hepcidin mRNA in hepatocellular carcinoma cell lines},
author = {Toki, Yasumichi and Sasaki, Katsunori, E-mail: k-sasaki@asahikawa-med.ac.jp and Tanaka, Hiroki and Yamamoto, Masayo and Hatayama, Mayumi and Ito, Satoshi and Ikuta, Katsuya and Shindo, Motohiro and Hasebe, Takumu and Nakajima, Shunsuke and Sawada, Koji and Fujiya, Mikihiro and Torimoto, Yoshihiro and Ohtake, Takaaki and Kohgo, Yutaka},
abstractNote = {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 of HAMP gene, 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 of HAMP gene by aberrantly splicing may be a suitable phenomenon to obtain the proliferating advantage of hepatoma cells. - Highlights: • An aberrant splicing variant of hepcidin mRNA lacking exon 2 of HAMP gene. • Absolute quantification of hepcidin mRNA by digital PCR amplification. • Hepatoma-derived cell lines have significant copies of variant-type hepcidin mRNA. • Truncated preprohepcidin is secreted from cells without posttranslational cleavage.},
doi = {10.1016/J.BBRC.2016.05.153},
journal = {Biochemical and Biophysical Research Communications},
number = 4,
volume = 476,
place = {United States},
year = {Fri Aug 05 00:00:00 EDT 2016},
month = {Fri Aug 05 00:00:00 EDT 2016}
}