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Activation of the PI3K/Akt/mTOR and MAPK Signaling Pathways in Response to Acute Solar-Simulated Light Exposure of

Yira Bermudez1, Steven P Stratton1, Clara Curiel-Lewandrowski1

  • 1College of Medicine, University of Arizona, Tucson, Arizona. The University of Arizona Cancer Center, Tucson, Arizona.

Cancer Prevention Research (Philadelphia, Pa.)
|June 3, 2015
PubMed

Insights

Solar-simulated ultraviolet light (SSL) activates key proteins in the PI3K/Akt and MAPK pathways, crucial for understanding skin cancer development. This research details the precise timing of these molecular changes following UV exposure.

Area of Science:

  • Molecular biology
  • Dermatology
  • Cancer research

Background:

  • Skin cancer incidence is rising, necessitating research into UV-induced molecular alterations.
  • Understanding UV-driven pathway activation is key for developing effective skin cancer prevention and therapies.

Purpose of the Study:

  • To investigate the temporal changes in protein phosphorylation within the PI3K/Akt and MAPK pathways after solar-simulated ultraviolet light (SSL) exposure.
  • To identify key molecular events in skin following UV irradiation for improved cancer control strategies.

Main Methods:

  • Immunohistochemistry was used to analyze protein phosphorylation in skin biopsies from 24 volunteers.
  • Samples were collected at various time points (baseline, 5 minutes, 1, 5, and 24 hours) post-SSL irradiation.
  • Key proteins in the PI3K/Akt and MAPK pathways, as well as p53, COX-2, and histone H3, were quantified.

Main Results:

  • SSL significantly activated Akt, mTOR, and downstream targets S6 and 4E-BP1 in the PI3K/Akt pathway over 24 hours.
  • The MAPK pathway showed early and sustained ERK1/2 activation, with p38 peaking at 1-5 hours.
  • Histone H3 phosphorylation, p53, COX-2 expression, and apoptosis increased, peaking at 5-24 hours post-SSL.

Conclusions:

  • SSL exposure triggers distinct temporal activation patterns in PI3K/Akt and MAPK signaling pathways.
  • Understanding the kinetics of these UV-induced molecular changes is vital for developing targeted skin cancer prevention and treatment strategies.

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