Hypoxia increases endothelin-1 mRNA expression but not immunoreactive endothelin in the medium of T98G glioblastoma cells under cytokine treatment

Yan Zhang, Yin Li, Kazuhito Totsune, Kumi Kikuchi, Osamu Murakami, Shigeki Shibahara, Kazuhiro Takahashi

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Endothelin-1 (ET-1) levels in the culture medium were considered to reflect the transcription of the ET-1 gene and the subsequent secretion of ET-1 from cultured cells. It has not been clarified how different ET-1 mRNA expression levels and immunoreactive (IR)-ET levels in the culture medium are in the cell culture system. We studied ET-1 mRNA expression levels and IR-ET levels in the medium of T98G glioblastoma cells treated with cytokines. T98G glioblastoma cells were cultured with cytokines (interferon-γ 100 U/ml, tumor necrosis factor-α 20 ng/ml and interleukin-1β 10 ng/ml) under normoxia or hypoxia (1% O2). Northern blot analysis showed that ET-1 mRNA expression levels were increased by tumor necrosis factor-α alone or a combination of tumor necrosis factor-α and interleukin-1β, or three cytokines, and the increase was further enhanced under hypoxia. Particularly, relative expression levels of ET-1 mRNA were significantly higher under hypoxia than in normoxia in the treatment with a combination of three cytokines. IR-ET levels in the medium were increased by treatment with tumor necrosis factor-α, interleukin-1β or a combination of tumor necrosis factor-α and interleukin-1β, or three cytokines. In contrast to the mRNA expression levels, IR-ET levels in the medium of T98G cells treated with a combination of three cytokines were rather decreased under hypoxia compared with those in normoxia. These findings indicate that hypoxia induces ET-1 mRNA expression in the treatment of three cytokines, but IR-ET levels in the medium do not reflect this induction in T98G glioblastoma cells.

Original languageEnglish
Pages (from-to)3003-3006
Number of pages4
JournalPeptides
Volume27
Issue number11
DOIs
Publication statusPublished - 2006 Nov

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Endocrinology
  • Cellular and Molecular Neuroscience

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