Photodynamic therapy is becoming a widely accepted form of
cancer treatment using a
photosensitizing agent and light. Our previous study has demonstrated that photoactivated
aloe-emodin induced anoikis and changes in cell morphology, which were in part mediated through its effect on cytoskeleton in lung
carcinoma H460 cells. However, the molecular mechanisms of these photoactivated
aloe-emodin-induced changes remain unknown. The present study demonstrated that the expression of
protein kinase Cδ (PKCδ) was triggered by
aloe-emodin and irradiation in H460 cells. Furthermore, the photoactivated
aloe-emodin-induced cell death and translocation of PKCδ from the cytosol to the nucleus was found to be significantly inhibited by
rottlerin, a PKCδ-selective inhibitor. Western blot analysis demonstrated that
rottlerin also reversed the decrease in
protein expression of cytoskeleton-related
proteins, such as rat
sarcoma (RAS), ras homolog gene family member A (RHO), p38,
heat shock protein 27 (HSP27),
focal adhesion kinase (FAK), α-
actinin and
tubulin, induced by photoactivated
aloe-emodin. Our findings suggest that the regulation of cytoskeleton-related
proteins mediated by PKCδ may be the mechanisms for the protective effects of
rottlerin against the photoactivated
aloe-emodin induced H460 cell death.