ALA-based photodynamic therapy in epithelial tumors: in vivo and in vitro models

Adriana Casas; Haydee Fukuda; Alcira Batlle

doi:10.1117/12.379888

29 March 2000 ALA-based photodynamic therapy in epithelial tumors: in vivo and in vitro models

Adriana Casas, Haydee Fukuda, Alcira Batlle

Proceedings Volume 3909, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy IX; (2000) https://doi.org/10.1117/12.379888
Event: BiOS 2000 The International Symposium on Biomedical Optics, 2000, San Jose, CA, United States

Abstract

PDT shows considerable potential as a treatment modality for superficial tumors. PDT is based on the accumulation of a photosensitizer in the target tissue. Subsequent illumination with light of an appropriate wavelength provokes a photochemical reaction that results in tumor destruction. Aminolevulinic acid (ALA) is a porphyrin precursor, and its administration result in the endogenous production of phototoxic porphyrins, which has been exploited for PDT. We assessed PDT efficacy employing both in vivo and in vitro models. We used papillomas, keratoacanthomas and in situ carcinomas chemically induced in the skin of SENCAR mice. Using ALA lotion and cream formulations, the maximal amount of porphyrin accumulation in papillomas was 5.52 (mu) g/g tissue. An energy of 150 of J/cm² was delivered by a copper-dye laser tuned at 630 nm. Microscopically, we found several signs of tissue destruction, more markedly in the upper strata of the in situ carcinomas. Papillomas, characterized by hyperkeratinization, were resistant to PDT. In our in vitro studies, we used an epithelial adenocarcinoma cell line. We tested ALA and its hexyl and methyl derivatives with the aim of increasing porphyrin synthesis. We found that hexyl-ALA was the best compound. When cultures incubated 3 hours in 0.6 mM ALA and 0.1 mM hexyl-ALA respectively were irradiated with 3 J/cm² only 5 percent of cells survived.

Citation Download Citation

Adriana Casas, Haydee Fukuda, and Alcira Batlle "ALA-based photodynamic therapy in epithelial tumors: in vivo and in vitro models", Proc. SPIE 3909, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy IX, (29 March 2000); https://doi.org/10.1117/12.379888

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