Trial Information

Transcriptional Profiling of the Epidermal Response to Solar-Simulated Ultraviolet Radiation

OBJECTIVES:

- Determine the global gene expression profiles in epidermal tissue of healthy
fair-skinned adults with Fitzpatrick skin type II after exposure to known doses of
solar-simulated ultraviolet radiation (ssUVR) (UVA).

- Determine the ability of an FDA-standardized sunscreen to alter ssUVR-induced
transcription profiles in vivo in these participants.

- Determine whether the transcriptional profiles of keratinocytes exposed to UVR in cell
culture are comparable to the profiles of keratinocytes in skin after similar levels of
UVR exposure.

OUTLINE: This is a pilot, dose-response study followed by an in vivo transcriptional
profiling study in 2 different groups.

- Pilot study (verification of ultraviolet radiation dose response): Participants are
initially exposed to solar-simulated ultraviolet radiation (ssUVR) (UVA) on the back to
determine the minimum erythema dose (MED). Between 22-24 hours after exposure,
participants undergo shave biopsy from each of the 9 UV exposure sites and 1 unexposed
skin site.

- Group 1 (determination of ssUVR and UVA in vivo transcriptional profiles): On day 1,
participants are initially exposed to ssUVR on the back to determine the MED. On day 2,
participants are exposed to ssUVR (3 sites) and UVA (3 sites) at the MED on the
buttocks. Between 22-24 hours after exposure (day 3), participants undergo shave biopsy
from each of the 6 UV exposure sites and 2 unexposed skin sites.

- Group 2 (determination of sunscreen-protected in vivo transcriptional profiles): On day
1, participants are initially exposed to ssUVR on the back to determine the MED. On day
2, participants are exposed to ssUVR on unprotected skin (3 sites) and
sunscreen-protected skin (3 sites) at the MED on the buttocks. Between 22-24 hours
after exposure (day 3), participants undergo shave biopsy from each of the 6 UV
exposure sites and 2 unexposed skin sites.

Biopsies from all participants are analyzed by microarray analysis. One of the unexposed
epidermal samples is used for primary keratinocyte culture.

PROJECTED ACCRUAL: A total of 6-56 participants (6 for the pilot study and 50 [25 per group]
for transcriptional profiling) will be accrued for this study within 2 months.