Induction of keratinocyte apoptosis by photosensitizing chemicals plus UVA.

Abstract

BACKGROUND:

The capacity of photosensitizing chemicals with ultraviolet A light (UVA) to induce apoptosis is one of the methods to assess their phototoxic and potentially photoallergic properties, since apoptotic cells may be easily presented by antigen-presenting cells.

OBJECTIVES:

We examined the photoaggravated ability to induce keratinocyte apoptosis of various chemicals that are known as causative agents of photocontact dermatitis and drug photosensitivity involving photoallergic and/or phototoxic mechanisms.

METHODS:

HaCaT keratinocytes were incubated with 3,3',4',5-tetrachlorosalicylanilide (TCSA), bithionol, diphenylhydramine, chlorpromazine, 6-methylcoumarin, sparfloxacin, and enoxacin at 10(-7) to 10(-4)M and irradiated with UVA at 4J/cm(2). As positive control, 8-methoxypsoralen (8-MOP) was also tested. Apoptosis and necrosis were evaluated by flow cytometric enumeration of annexin V(+) 7-AAD(-) and annexin V(+) 7-AAD(+) cells, respectively. The expression of apoptosis-related molecules, caspase-3 and poly (ADP-ribose) polymerase (PARP), was tested by flow cytometric and Western blotting analyses.

RESULTS:

In a comparison with non-irradiated cells, significant apoptosis was found in TCSA, bithionol, chlorpromazine, sparfloxacin and enoxacin at 10(-4) or 10(-5)M as well as 8-MOP as assessed by both annexin V and active caspase-3 stainings, while necrosis occurred in most of these chemicals at 10(-4)M. Neither apoptosis nor necrosis was seen in diphenylhydramine or 6-methylcoumarin. PARP were activated in HaCaT cells phototreated with TCSA, bithionol and chlorpromazine.

CONCLUSIONS:

We suggest that our method is useful for in vitro assessment of phototoxicity and potential photoallergenicity of chemicals.

• Authors: Masako Kurita, Takatoshi Shimauchi, Miwa Kobayashi, Kenji Atarashi, Koji Mori, Yoshiki Tokura
• Journal: Journal of dermatological science (J Dermatol Sci) Vol. 45 Issue 2 Pg. 105-12 (Feb 2007) ISSN: 0923-1811 [Print] Netherlands
• PMID: 17141480 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anesthetics, Local
• Anti-Infective Agents, Local
• Antipsychotic Agents
• Antitubercular Agents
• Coumarins
• Enzyme Inhibitors
• Fluoroquinolones
• Photosensitizing Agents
• Salicylanilides
• Enoxacin
• Diphenhydramine
• Bithionol
• 6-methylcoumarin
• 3,3',4',5-tetrachlorosalicylanilide
• sparfloxacin
• Chlorpromazine

Topics

• Anesthetics, Local (pharmacology)
• Anti-Infective Agents, Local (pharmacology)
• Antipsychotic Agents (pharmacology)
• Antitubercular Agents (pharmacology)
• Apoptosis (drug effects, radiation effects)
• Bithionol (pharmacology)
• Cell Line, Transformed
• Chlorpromazine (pharmacology)
• Coumarins (pharmacology)
• Diphenhydramine (pharmacology)
• Enoxacin (pharmacology)
• Enzyme Inhibitors (pharmacology)
• Fluoroquinolones (pharmacology)
• Humans
• Keratinocytes (cytology, drug effects, radiation effects)
• Necrosis
• Photosensitizing Agents (pharmacology)
• Salicylanilides (pharmacology)
• Ultraviolet Rays