Interleukin-1alpha enhances IL-8 secretion through p38 mitogen-activated protein kinase and reactive oxygen species signaling in human pancreatic cancer cells.

Abstract

BACKGROUND:

Interleukin (IL)-1alpha plays an important role in modulating the expression of various growth factors and angiogenic factors in tumor cells. In here, we investigated effect of IL-1alpha on IL-8 secretion in human pancreatic cancer cells and underlying signal transduction pathways.

MATERIAL/METHODS:

IL-8 expression and secretion by pancreatic cancer cells was measured by Western blot and enzyme-linked immunosorbent assay (ELISA), respectively. Activation of extracellular signal regulated kinases-1/2 (ERK-1/2), p38 mitogen-activated protein kinase (MAPK), c-jun aminoterminal kinase, Akt, and nuclear factor-kappaB (NF-kappaB) was determined by Western blot. Involvement of reactive oxygen species (ROS) were examined by measuring the H2O2. Activity of activator factor-1 (AP-1) and NF-kappaB was examined by electrophoretic mobility sift assay (EMSA). Proliferation of human umbilical vein endothelial cells (HUVECs) was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide dye reduction method and cell count.

RESULTS:

IL-1alpha modulated IL-8 secretion and induced activation of ERK-1/2 and p38 MAPK. Specific inhibitors for MEK-1 and p38 MAPK suppressed IL-8 secretion. IL-1alpha also induced production of ROS. Exogenous H2O2 enhanced IL-8 secretion and N-acetyl cysteine (NAC) prevented IL-1alpha-induced ROS production and IL-8 secretion. EMSA confirmed that IL-1alpha increased DNA-binding activity of AP-1 and NF-kappaB. Inhibitors and ROS scavenger studies revealed that upstream signalings for AP-1 and NF-kappaB were MAPK and ROS, respectively. Conditioned media from pancreatic cancer cells pretreated with IL-1alpha remarkably stimulated in vitro HUVECs growth.

CONCLUSIONS:

These results suggest that MAPK/AP-1 and ROS/NF-kappaB signaling pathways are involved in IL-1alpha-induced IL-8 secretion and that these paracrine signaling pathways enhance endothelial cell proliferation.

• Authors: Hirozumi Sawai, Hitoshi Funahashi, Yuji Okada, Yoichi Matsuo, Masaki Sakamoto, Minoru Yamamoto, Hiromitsu Takeyama, Tadao Manabe
• Journal: Medical science monitor : international medical journal of experimental and clinical research (Med Sci Monit) Vol. 11 Issue 10 Pg. BR343-50 (Oct 2005) ISSN: 1234-1010 [Print] United States
• PMID: 16192891 (Publication Type: Journal Article)

Chemical References

• Culture Media, Conditioned
• Interleukin-1
• Interleukin-8
• NF-kappa B
• Reactive Oxygen Species
• Transcription Factor AP-1
• p38 Mitogen-Activated Protein Kinases

Topics

• Blotting, Western
• Culture Media, Conditioned
• Electrophoretic Mobility Shift Assay
• Enzyme-Linked Immunosorbent Assay
• Humans
• Interleukin-1 (physiology)
• Interleukin-8 (metabolism)
• NF-kappa B (metabolism)
• Pancreatic Neoplasms (enzymology, metabolism, pathology)
• Reactive Oxygen Species
• Signal Transduction (physiology)
• Transcription Factor AP-1 (metabolism)
• Tumor Cells, Cultured
• p38 Mitogen-Activated Protein Kinases (metabolism)