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Ultraviolet radiation increases the toxicity of pyrene, 1-aminopyrene and 1-hydroxypyrene to human keratinocytes.

Ekunwe SI, Hunter RD, Hwang HM - Int J Environ Res Public Health (2005)

Bottom Line: The purpose of this study was to assess the effects of UV-A irradiated pyrene (Pyr), 1-aminopyrene (1-AP) and 1-hydroxypyrene (1-HP) on human keratinocytes, the skin primary site of UV irradiated PAH exposure.Our findings indicate that simultaneous treatment of human keratinocyte cell line, HaCaT, with 1.0 microg/ml pyrene, 1-AP or 1-HP and 3.9 J/cm2/min UV-A light resulted in significant inhibition of cell proliferation.Approximately 100% of the cells died in the case of UV-A irradiated 1-AP and 1-HP.

View Article: PubMed Central - PubMed

Affiliation: Microbial Molecular Genetics, Cancer and Phytonutriceuticals Research Laboratory, Jackson, MS 39217, USA. stephen.i.ekunwe@jsums.edu

ABSTRACT
Over the past several years, a great deal of interest has been focused on the harmful effects of ultraviolet (UV) radiation to human skin. UV light has been implicated in aging, sunburn and skin cancer. Few studies, however, have been done to determine the effects that UV light, in conjunction with other environmental contaminants, may have on human skin. Polycyclic Aromatic Hydrocarbons (PAHs) are a class of compounds that have been reported to be toxic, mutagenic and carcinogenic to many eukaryotic organisms. UV light is also known to increase the toxicity of PAHs through photo-activation and photo-modification. The purpose of this study was to assess the effects of UV-A irradiated pyrene (Pyr), 1-aminopyrene (1-AP) and 1-hydroxypyrene (1-HP) on human keratinocytes, the skin primary site of UV irradiated PAH exposure. Our findings indicate that simultaneous treatment of human keratinocyte cell line, HaCaT, with 1.0 microg/ml pyrene, 1-AP or 1-HP and 3.9 J/cm2/min UV-A light resulted in significant inhibition of cell proliferation. Approximately 100% of the cells died in the case of UV-A irradiated 1-AP and 1-HP. In the case of UV-A irradiated pyrene, more than 70% of the cells died, indicating that UV-A is able to transform these PAHs into more harmful intermediates.

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Effects of 1-aminopyrene on HaCaT proliferation. HaCaT cells were grown in 35mm plates to subconfluent in CGM. Cells were serum starved for 24 hours and then treated with pyrene at 0.01, 0.1, 1.0 and 10.0μg/ml concentrations for 18 hours. Thymidine incorporation assay was then performed as described in materials and methods. Results represent the mean +/− SD values of experiment performed in triplicate. [* indicates that treatment mean is significantly different from negative control according to Dunett test (p<0.05)].
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f4-ijerph-02-00058: Effects of 1-aminopyrene on HaCaT proliferation. HaCaT cells were grown in 35mm plates to subconfluent in CGM. Cells were serum starved for 24 hours and then treated with pyrene at 0.01, 0.1, 1.0 and 10.0μg/ml concentrations for 18 hours. Thymidine incorporation assay was then performed as described in materials and methods. Results represent the mean +/− SD values of experiment performed in triplicate. [* indicates that treatment mean is significantly different from negative control according to Dunett test (p<0.05)].

Mentions: PAHs are also known to be toxic to human cells, causing lung cancer when inhaled and skin cancer when exposed by skin contact [9]. Results obtained in this set of experiment suggest a biphasic response to PAH exposure. At low concentrations, pyrene caused stimulation of HaCaT proliferation while 1-HP and 1-AP inhibit cell proliferation; and at 10μg/mL, pyrene, 1-AP and 1-HP significantly inhibit HaCaT proliferation (Figures 2–4). It is an established fact that substituted PAH derivatives are more soluble than their parent compounds, and are therefore more accessible and toxic to the cells [10]. This could explain why, at low concentrations, the substituted PAHs were more toxic to the HaCaT cells than the parent compound pyrene.


Ultraviolet radiation increases the toxicity of pyrene, 1-aminopyrene and 1-hydroxypyrene to human keratinocytes.

Ekunwe SI, Hunter RD, Hwang HM - Int J Environ Res Public Health (2005)

Effects of 1-aminopyrene on HaCaT proliferation. HaCaT cells were grown in 35mm plates to subconfluent in CGM. Cells were serum starved for 24 hours and then treated with pyrene at 0.01, 0.1, 1.0 and 10.0μg/ml concentrations for 18 hours. Thymidine incorporation assay was then performed as described in materials and methods. Results represent the mean +/− SD values of experiment performed in triplicate. [* indicates that treatment mean is significantly different from negative control according to Dunett test (p<0.05)].
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3814697&req=5

f4-ijerph-02-00058: Effects of 1-aminopyrene on HaCaT proliferation. HaCaT cells were grown in 35mm plates to subconfluent in CGM. Cells were serum starved for 24 hours and then treated with pyrene at 0.01, 0.1, 1.0 and 10.0μg/ml concentrations for 18 hours. Thymidine incorporation assay was then performed as described in materials and methods. Results represent the mean +/− SD values of experiment performed in triplicate. [* indicates that treatment mean is significantly different from negative control according to Dunett test (p<0.05)].
Mentions: PAHs are also known to be toxic to human cells, causing lung cancer when inhaled and skin cancer when exposed by skin contact [9]. Results obtained in this set of experiment suggest a biphasic response to PAH exposure. At low concentrations, pyrene caused stimulation of HaCaT proliferation while 1-HP and 1-AP inhibit cell proliferation; and at 10μg/mL, pyrene, 1-AP and 1-HP significantly inhibit HaCaT proliferation (Figures 2–4). It is an established fact that substituted PAH derivatives are more soluble than their parent compounds, and are therefore more accessible and toxic to the cells [10]. This could explain why, at low concentrations, the substituted PAHs were more toxic to the HaCaT cells than the parent compound pyrene.

Bottom Line: The purpose of this study was to assess the effects of UV-A irradiated pyrene (Pyr), 1-aminopyrene (1-AP) and 1-hydroxypyrene (1-HP) on human keratinocytes, the skin primary site of UV irradiated PAH exposure.Our findings indicate that simultaneous treatment of human keratinocyte cell line, HaCaT, with 1.0 microg/ml pyrene, 1-AP or 1-HP and 3.9 J/cm2/min UV-A light resulted in significant inhibition of cell proliferation.Approximately 100% of the cells died in the case of UV-A irradiated 1-AP and 1-HP.

View Article: PubMed Central - PubMed

Affiliation: Microbial Molecular Genetics, Cancer and Phytonutriceuticals Research Laboratory, Jackson, MS 39217, USA. stephen.i.ekunwe@jsums.edu

ABSTRACT
Over the past several years, a great deal of interest has been focused on the harmful effects of ultraviolet (UV) radiation to human skin. UV light has been implicated in aging, sunburn and skin cancer. Few studies, however, have been done to determine the effects that UV light, in conjunction with other environmental contaminants, may have on human skin. Polycyclic Aromatic Hydrocarbons (PAHs) are a class of compounds that have been reported to be toxic, mutagenic and carcinogenic to many eukaryotic organisms. UV light is also known to increase the toxicity of PAHs through photo-activation and photo-modification. The purpose of this study was to assess the effects of UV-A irradiated pyrene (Pyr), 1-aminopyrene (1-AP) and 1-hydroxypyrene (1-HP) on human keratinocytes, the skin primary site of UV irradiated PAH exposure. Our findings indicate that simultaneous treatment of human keratinocyte cell line, HaCaT, with 1.0 microg/ml pyrene, 1-AP or 1-HP and 3.9 J/cm2/min UV-A light resulted in significant inhibition of cell proliferation. Approximately 100% of the cells died in the case of UV-A irradiated 1-AP and 1-HP. In the case of UV-A irradiated pyrene, more than 70% of the cells died, indicating that UV-A is able to transform these PAHs into more harmful intermediates.

Show MeSH
Related in: MedlinePlus