Sharma, Mrinalini ; Dube, Alok ; Bansal, Harsha ; Gupta, Pradeep Kumar (2004) Effect of pH on uptake and photodynamic action of chlorin p6 on human colon and breast adenocarcinoma cell lines Photochemical & Photobiological Sciences, 3 (2). pp. 231-235. ISSN 1474-905X
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Related URL: http://dx.doi.org/10.1039/ b303986m
Abstract
The effect of reducing the extracellular pH from 7.4 to 6.0 on the uptake and photosensitivity of chlorin p6, a potential photosensitising drug, has been investigated using two mammalian cell lines, human colon (Colo-205) and breast (MCF-7) adenocarcinoma cells. In Colo-205 cells, the uptake and phototoxicity of chlorin p6 was observed to increase as the pH of the incubation medium decreased. For light doses of up to ~6 kJ m-2, although there was no evidence of mitochondrial damage, a significant reduction in Neutral Red uptake was observed, signifying damage to lysosomes. At higher light doses, significant mitochondrial damage was observed, accompanied by saturation of the lysosomal damage. This suggests light-induced relocalization of the photosensitizer from lysosomes to mitochondria. Furthermore, it was found that for a given light dose, lysosomes exhibit greater photosensitivity at lower pH. Since chlorin p6 is known to aggregate at pH 6.0, this observation suggests that the dye accumulation in these cells mainly takes place through endocytosis. In contrast, no significant variation in uptake, photosensitivity, and sites of photodamage was observed for MCF-7 cells at different extracellular pH. Additionally, the lower photosensitivity of lysosomes as compared to mitochondria in these cells suggests chlorin p6 is taken up through diffusion rather than endocytosis.
Item Type: | Article |
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Source: | Copyright of this article belongs to Royal Society of Chemistry. |
ID Code: | 22306 |
Deposited On: | 23 Nov 2010 08:53 |
Last Modified: | 17 May 2016 06:22 |
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