How to translate text using browser tools
1 November 2001 Extreme Dark Cytotoxicity of Nile Blue A in Normal Human Fibroblasts
Zhimin Tong, Gurmit Singh, Andrew J. Rainbow
Author Affiliations +

Early reports using mouse models indicated that Nile Blue A (NBA) is taken up more efficiently by tumor cells than normal tissue and retards tumor growth. NBA also shows both dark toxicity and phototoxicity of human tumor cells in vitro. However, studies on the dark toxicity of NBA and the effects of NBA-mediated photodynamic treatment in normal human cells are lacking. In the current study we have examined the cytotoxicity of NBA in normal human fibroblasts, spontaneously immortalized Li-Fraumeni Syndrome (LFS) cells and three different human tumor cell lines. The normal human fibroblasts showed extreme sensitivity to NBA compared with LFS cells and the human tumor cell lines. Treatment with 0.1 μg/mL of NBA for 1 h reduced the colony formation of normal human fibroblasts by greater than 95%, but had no significant effect on the colony formation of LFS cells. No significant numbers of apoptotic cells were detected in either normal human fibroblasts or LFS cells following this drug concentration. Thus, unlike photodynamic therapy with some other photosensitizers, the dark toxicity of NBA was not caused by apoptosis. Although the drug uptake was higher in normal human fibroblasts compared with LFS cells, the difference in sensitivity between normal human fibroblasts and LFS cells could not be accounted for by the difference in drug uptake alone. In addition, we could not detect any significant photocytotoxic effect of NBA in either normal human fibroblasts or LFS cells for a drug concentration of 0.05 μg/mL at light exposures of up to 6.7 J/cm2. These data indicate an extreme sensitivity of normal human fibroblasts to NBA and an inability to produce a significant photocytotoxic effect on human cells using NBA concentrations that have relatively low toxicity for normal human fibroblasts.

Zhimin Tong, Gurmit Singh, and Andrew J. Rainbow "Extreme Dark Cytotoxicity of Nile Blue A in Normal Human Fibroblasts," Photochemistry and Photobiology 74(5), 707-711, (1 November 2001).<0707:EDCONB>2.0.CO;2
Received: 5 June 2001; Accepted: 1 August 2001; Published: 1 November 2001

This article is only available to subscribers.
It is not available for individual sale.

Get copyright permission
Back to Top