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The nitrogen mustard melphalan activates mitogen-activated phosphorylated kinases (MAPK), nuclear factor-kappaB and

Camilla Osterlund1, Bo Lilliehöök, Barbro Ekstrand-Hammarström

  • 1Division of NBC Defence, Swedish Defence Research Agency, Umeå, Sweden.

Journal of Applied Toxicology : JAT
|July 19, 2005
PubMed

Insights

Alkylating agents like melphalan cause lung epithelial cell death and activate stress pathways. This response includes mitogen-activated protein kinase (MAPK) signaling and tumor necrosis factor-alpha (TNF-alpha) production, promoting inflammation.

Area of Science:

  • Cell Biology
  • Toxicology
  • Immunology

Background:

  • Respiratory epithelial cells are crucial for lung defense.
  • Alkylating agents are used in chemotherapy but can have toxic side effects.
  • Understanding cellular responses to these agents is vital for safety and efficacy.

Purpose of the Study:

  • To investigate the effects of the alkylating agent melphalan on human bronchial and alveolar epithelial cells.
  • To identify the molecular signaling pathways activated by melphalan exposure.
  • To assess the impact of melphalan on inflammatory mediator expression and cell adhesion.

Main Methods:

  • Exposure of BEAS-2B and A549 cells to varying concentrations and durations of melphalan.
  • Assessment of cell viability using standard assays.
  • Analysis of mitogen-activated protein kinase (MAPK) phosphorylation (ERK1/2, p38).
  • Evaluation of nuclear factor-kappaB (NF-kappaB) translocation.
  • Measurement of tumor necrosis factor-alpha (TNF-alpha) mRNA levels.
  • Quantification of intercellular adhesion molecule-1 (ICAM-1) expression and monocyte adhesion.

Main Results:

  • Human bronchial (BEAS-2B) cells showed higher sensitivity to melphalan-induced cell death than alveolar (A549) cells.
  • Melphalan rapidly activated stress-induced MAPK pathways (ERK1/2, p38) and NF-kappaB signaling within minutes.
  • Elevated TNF-alpha mRNA levels and increased ICAM-1 expression were observed.
  • Melphalan exposure led to enhanced monocyte adhesion to epithelial cells in vitro.

Conclusions:

  • Alkylating compounds like melphalan induce both cell death and inflammatory signaling in lung epithelial cells.
  • Melphalan activates stress-associated MAPK pathways and upregulates inflammatory mediators.
  • These responses contribute to the recruitment of inflammatory cells, suggesting a role in melphalan-induced lung toxicity.

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