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Human glioblastoma cells produce 77 amino acid interleukin-8 (IL-8(77))
1Department of Neurosurgery, Hokkaido University School of Medicine, Sapporo, Japan.
Abstract:
The production of interleukin 8 (IL-8), a neutrophil chemotactic factor, and its amino acid sequence were examined in glioblastoma cell lines in vitro. Neutrophil chemotactic activity was demonstrated in 9 conditioned media of 15 human glioblastoma cell lines. Tumor necrosis factor (TNF)-alpha stimulated secretion of the activity in 7 lines and induced secretion in 4 other lines. ELISA quantification disclosed that the conditioned media contained interleukin 8 (IL-8) in an amount equivalent to the chemotactic activity. The IL-8 secretion increased with the stimulation by TNF-alpha. Northern blot analysis and the RT-PCR method confirmed expression of mRNA in the glioblastoma cells and its augmentation by TNF-alpha and/or IL-beta. Reversed-phase HPLC following ion-exchange chromatography revealed that the chemotactic activity was a single peptide, which was determined to be IL-8 by the retention time and ELISA. Furthermore, amino acid analysis disclosed that a major part of the glioblastoma-cell derived IL-8 peptide was 77 amino acid IL-8 (IL-8(77); with the N-terminal sequence AVLPRSAKELRCQCI-).
Insights
Glioblastoma cells produce interleukin 8 (IL-8), a key factor attracting neutrophils. Tumor necrosis factor-alpha enhances this IL-8 production, suggesting a role in glioblastoma
Area of Science:
- Neuro-oncology
- Immunology
- Molecular Biology
Background:
- Glioblastoma is an aggressive brain tumor.
- Interleukin 8 (IL-8) is a neutrophil chemotactic factor involved in inflammation.
Purpose of the Study:
- To investigate the production and characteristics of IL-8 in glioblastoma cell lines.
- To determine the influence of cytokines like TNF-alpha on IL-8 secretion.
Main Methods:
- Cell culture of human glioblastoma lines.
- Assays for neutrophil chemotactic activity.
- ELISA for IL-8 quantification.
- Northern blot and RT-PCR for mRNA analysis.
- HPLC and amino acid sequencing for peptide characterization.
Main Results:
- Neutrophil chemotactic activity was detected in 9 out of 15 glioblastoma cell lines.
- Tumor necrosis factor-alpha (TNF-alpha) stimulated IL-8 secretion.
- IL-8 mRNA expression was confirmed and upregulated by TNF-alpha and IL-1beta.
- The chemotactic factor was identified as IL-8, with a major component being the 77-amino acid form (IL-8(77)).
Conclusions:
- Glioblastoma cells produce biologically active IL-8.
- Cytokine stimulation, particularly by TNF-alpha, enhances IL-8 production.
- IL-8 may play a role in the inflammatory response within the glioblastoma microenvironment.