Characteristic Morphological Changes and Rapid Actin Accumulation in Serum-MAF-treated Macrophages

Anticancer Res. 2019 Aug;39(8):4533-4537. doi: 10.21873/anticanres.13630.

Abstract

Background/aim: Serum-derived macrophage activating factor, serum-MAF, is known to increase the phagocytic activity of macrophages by enhancing the engulfment efficiency. To elucidate the mechanisms underlying phagocytic activation, morphological changes were observed and analyzed.

Materials and methods: Morphological changes in macrophages were observed and quantitatively analyzed using scanning electron microscope (SEM) and confocal microscope.

Results: SEM and confocal microscopy images revealed frill-like structures and active actin accumulations, respectively, in serum-MAF treated macrophages. Actin accumulation was induced within 5 min following serum-MAF treatment.

Conclusion: Serum-MAF induced a rapid rearrangement of cytoskeletal actin and enhanced phagocytic activity. Findings of the current study may contribute to the development of techniques that facilitate activation of the human immune system, which in turn may be beneficial for cancer immunotherapy.

Keywords: THP-1; actin accumulation; morphological change; serum-MAF (serum-derived macrophage activating factor); time-lapse image.

MeSH terms

  • Actins / chemistry*
  • Actins / ultrastructure
  • Humans
  • Immunotherapy
  • Macrophage Activation / drug effects
  • Macrophages / drug effects*
  • Macrophages / metabolism
  • Microscopy, Confocal
  • Microscopy, Electron, Scanning
  • Phagocytosis / drug effects*
  • Proto-Oncogene Proteins c-maf / genetics
  • Proto-Oncogene Proteins c-maf / pharmacology*
  • U937 Cells
  • Vitamin D-Binding Protein / chemistry
  • Vitamin D-Binding Protein / metabolism

Substances

  • Actins
  • MAF protein, human
  • Proto-Oncogene Proteins c-maf
  • Vitamin D-Binding Protein