Paper
2 March 2010 Vitamin D as a potential enhancer of aminolevulinate-based photodynamic therapy for nonmelanoma skin cancer
Edward V. Maytin, Sanjay Anand, Natasha Atanaskova, Clara Wilson
Author Affiliations +
Abstract
Vitamin D3 (Vit D3) is a hormone essential for normal bone and cardiovascular health, and may participate in preventing nonmelanoma skin cancers (NMSC). Calcitriol (1,25 dihydroxyD3) is the active form of the hormone. We showed previously that calcitriol is a potent inducer of protoporphyrin IX (PpIX) in skin keratinocytes grown in organotypic cultures. Here, we investigated the ability of Vit D3 to enhance PpIX levels within skin tumors in vivo. Squamous tumors, generated by chemical carcinogenesis in mice, were pretreated for 3 days with topical calcitriol. Then 5-aminolevulinic acid (5-ALA) was applied topically, and PpIX levels were measured by noninvasive fluorimetry and in biopsied tissue. Calcitriol pretreatment resulted in a 3 to 4-fold elevation of PpIX in tumors, relative to no pretreatmen, providing significantly more photosensitizer available for tumor destruction. For deep tumors, topical calcitriol may not penetrate sufficiently. Therefore we explored whether systemic Vit D3, given short-term (3 days), might elevate PpIX within NMSC in a deep tumor model (subcutaneously-implanted A431 human squamous carcinoma cells). Defined amounts of calcitriol were injected into the mice for 3 d, followed by systemic 5-ALA, tissue biopsy, and confocal microscopic measurement of PpIX in frozen tissues. PpIX was clearly elevated after systemically delivered calcitriol. More work is needed, but if the amount of calcitriol required to elevate PpIX levels proves to be small, then the approach may ultimately prove attractive. Since most Americans are currently Vitamin D deficient, a small increase in calcitriol might be possible without risk of hypercalcemia.
© (2010) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Edward V. Maytin, Sanjay Anand, Natasha Atanaskova, and Clara Wilson "Vitamin D as a potential enhancer of aminolevulinate-based photodynamic therapy for nonmelanoma skin cancer", Proc. SPIE 7551, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XIX, 755105 (2 March 2010); https://doi.org/10.1117/12.847183
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KEYWORDS
Tumors

Skin

Photodynamic therapy

Skin cancer

Confocal microscopy

Tissues

Analog electronics

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