ALA-induced photodynamic effect on vitality, apoptosis, and secretion of vascular endothelial growth factor (VEGF) by colon cancer cells in normoxic environment in vitro.

BACKGROUND: Cancer therapy is often based on combination of conventional methods of cancer treatment with immunotherapy. Photodynamic therapy (PDT) is one of the immunomodulating methods used in oncology. We examined how PDT influences the secretory activity of colon cancer cells in vitro, especially the secretion of vascular endothelial growth factor (VEGF) in aerobic conditions. METHODS: We used two cancer cell lines with different malignancy potentials: a metastatic SW620 line and a non-metastatic SW480 line. In the first stage of the experiment, we exposed each cell line to three different concentrations of photosensitizer's precursor: 5-aminolevulinic acid (ALA) and varying levels of light radiation, after which we assessed cell viability and apoptosis induction in these lines, using the MTT and LDH assays. Then, we determined the secretion of VEGF by these cells in aerobic conditions and under the ALA-PDT parameters at which cells presented the highest viability. RESULTS: Photodynamic treatment with ALA did not influence on VEGF secretion by the non-metastatic SW480 cells, but caused a decrease in VEGF secretion by the metastatic SW 620 cell line by 29% (p<0.05). SW 620 cell line secreted more actively VEGF than the SW480 cells, both before and after photo dynamic therapy (p<0.05). CONCLUSION: The outcome of this in vitro study presented a beneficial effect of ALA-PDT, resulting in a decrease of VEGF secretion in the more malignant SW620 cell lines. Further studies should be considered to confirm the clinical relevance of this finding.

Vascular-targeted photodynamic therapy in the treatment of neovascular age-related macular degeneration: Clinical perspectives.

Vascular targeted photodynamic therapy (VTP), with use of verteporfin as a photosensitizer is one of the few therapies, which has been shown to effectively slow the progression of the "wet" form of age-related macular degeneration (AMD), and even to stabilize visual acuity over many years. Although, due to considerable advance of AMD treatment, it is currently not recommended in monotherapy of AMD, however, its combination with steroids and anti-angiogenic biologic drugs may reveal high therapeutic potential in the treatment of neovascular AMD. The future of VTP as a method of AMD treatment is development of new selective and targeted photosensitizer and combination of this method with other therapeutic strategies targeting cellular structures or pathways involved in AMD progression.

Optical biopsy using spectral camera in BCC and oral leukoplakia.

Basal cell carcinoma is one of the most common neoplasmatic diseases of the skin. Oral leukoplakia is precancerous stage. Early diagnosis of both diseases gives very good treatment results. Fluorescence spectroscopy is a new modality of diagnostics using excitation of absorbed PPIX in tumor. Spectroscopy is an objective method showing concentration and emission spectrum of protoporphyrin IX. In fluorescence spectroscopy with PPIX we used diode light 405 nm to induce fluorescence and observed significant emission peak at 630 nm. Fluorescence spectroscopy is based on searching of emission peaks of photosensitizer in areas of BCC and oral leukoplakia. In our study we used spectral camera measuring spectrum from pictures taken in different wavelengths between 570 nm and 650 nm. The pictures taken with this camera were compared with the pictures captured with Xillix Onco Life system. 20 patients with histopathologically confirmed BCC and 10 with oral leukoplakia were examinated with spectral camera and with Xillix Onco Life system 8h after local instillation of delta aminolevulinic acid. Our spectral camera made pictures with different filters for wavelength between 570 nm and 650 nm showing highest fluorescence intensity in 630 nm. Captured spectral lines were compared with NCV (numerical color value) from Xillix Onco Life. All of spectral lines taken from neoplasmatic tissues were compared with spectral lines taken from healthy tissues in symmetrical areas of body. Results were statistically processed. All of spectral lines taken from neoplasmatic tissues showed significant peak at 630 nm in the area of BCC and oral leukoplakia in all of the examinated patients. Spectral lines taken from healthy tissues were significantly different. There was no peak in 630 nm and fluorescence intensity was decreasing from 570 nm to 630 nm. Intensity of fluorescence in 630 nm was in high correlation with NCV from Xillix Onco Life.