Photo-activated 5-hydroxyindole-3-acetic acid induces apoptosis of prostate and bladder cancer cells

J Photochem Photobiol B. 2011 Apr 4;103(1):50-6. doi: 10.1016/j.jphotobiol.2011.01.011. Epub 2011 Jan 21.


5-Hydroxyindole-3-acetic acid (5-HIAA), an indole derivative, is the main metabolite of serotonin in the human body. We determined whether or not ultraviolet B (UVB)-activated 5-HIAA (5-HIAA(UVB)) affects the viability of human prostate (LnCaP and PC-3) and bladder cancer cells (TCCSUP). While 5-HIAA alone had no cytotoxic effect at <1mM, 5-HIAA(UVB) induced LnCaP, PC-3, and TCCSUP cell death in a time- and dose-dependent manner. Cell cycle analysis showed that 5-HIAA(UVB) markedly increased the sub-G(0)/G(1) phase and resulted in cell cycle disruption. To elucidate the death mechanism by 5-HIAA(UVB), we examined the signal transduction pathways related to apoptosis using Western blot analysis. 5-HIAA(UVB) led to phosphorylation of stress-activated signaling proteins, such as c-Jun N-terminal kinase (JNK) and/or p38 mitogen-activated protein kinase (MAPK). Furthermore, 5-HIAA(UVB) activated caspase-8, -9, and -3 and cleaved poly(ADP-ribose) polymerase (PARP), which are indicators of apoptosis. From these findings, the present study demonstrated that 5-HIAA(UVB) induces apoptotic cell death of prostate and bladder cancer cells via stress-mediated signaling and apoptotic pathways. Therefore, we suggest that 5-HIAA might be used as a new photosensitizer for photodynamic cancer therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects*
  • Apoptosis / radiation effects*
  • Cell Line, Tumor
  • G1 Phase / drug effects
  • G1 Phase / radiation effects
  • Humans
  • Indoles / pharmacology*
  • Light*
  • Male
  • Photosensitizing Agents / pharmacology*
  • Prostatic Neoplasms / pathology*
  • Resting Phase, Cell Cycle / drug effects
  • Resting Phase, Cell Cycle / radiation effects
  • Signal Transduction / drug effects
  • Signal Transduction / radiation effects
  • Urinary Bladder Neoplasms / pathology*


  • Indoles
  • Photosensitizing Agents
  • 5-(hydroxy-3-indolyl)lactic acid