Transcriptional alteration of matrix-related gene expression in cultured human disc cells by nanoparticles of a bismethanophosphonate fullerene.

Fullerene and its derivatives have been extensively studied in the biomedical field. Their biological activities towards various cell types have been reported, and previous results have implicated their potential uses as photosensitizers in photodynamic therapy of tumour and photoinactivation of bacteria and viruses, antioxidative/cytoprotective reagents and carriers for drug delivery. We describe here the effects of a BMPF (bismethanophosphonate fullerene) on matrix-related gene expression in cultured human disc cells by real-time reverse transcriptase PCR. Mediation of BMPF into water by DMSO leads to formation of an aqueous suspension of nanoparticles (denoted as nano-BMPF) with a very narrow size distribution and an average size of 136.3 nm. Moreover, nano-BMPF could induce a down-regulation of gene expression of matrix proteins aggrecan, type I collagen and type II collagen and an up-regulation of gene expression of matrix metalloproteinase 3. IL-1Ra (IL-1 receptor antagonist), but not IL-1 receptor 1, is transcriptionally inhibited by nano-BMPF. These data indicated a disc degeneration-inducing activity of nano-BMPF, raising concerns of possible adverse effects, while a fullerene-based treatment of disc diseases is employed.

Involvement of reactive oxygen species and calcium in photo-induced membrane damage in HeLa cells by a bis-methanophosphonate fullerene.

Photo-excited bioactivities of fullerene derivatives are attracting much attention. In this report, a bis-methanophosphonate fullerene (BMPF) and the other two fullerene derivatives, a bis-malonic acid fullerene (BMAF) and a fullerol were incubated with HeLa cells and irradiated with a green light emitted from a mercury lamp on a fluorescent microscopy. By using DNA fluorescent probe propidium iodide staining method, damage towards cell membrane could be detected when cells were treated by irradiation altogether with BMPF or BMAF at a low concentration (4 microM), and the damage was dose-dependent. The activity of BMPF was much higher than that of BMAF, while fullerol had no effects under the same condition. It was also revealed that different kinds of reactive oxygen species (ROS) correlated to BMPF and BMAF. Additionally, presence of extracellular calcium could promote the activities of both derivatives, while removal of extracellular calcium could not abort their membrane-damaged activities. These results indicated that ROS and calcium were involved in the photosensitization of fullerene derivatives, and BMPF was a superior photosensitizer which would find potential application in biomedical field.

Photo-induced damages of cytoplasmic and mitochondrial membranes by a [C60]fullerene malonic acid derivative.

The biological activities of fullerene derivatives have attracted much attention in the last decade. In this paper, effects of dimalonic acid C(60) (DMA C(60)) on cytoplasmic membrane, intracellular calcium concentration ([Ca(2+)](i)), and mitochondrial membrane in HeLa cells were studied by using laser scanning confocal microscopy together with fluorescent probes propidium iodide (PI), fluo-3 acetoxymethyl ester (fluo-3 AM), and tetramethyl rhodamine methyl ester (TMRM). The data showed that under laser irradiation produced by a Kr/Ar laser source with a low power less than 1 mW, DMA C(60) might induce damages against both cytoplasmic and mitochondrial membranes in a time- and dose-dependent manner. Prior to leakage of cytoplasmic membrane, a transient increase in [Ca(2 +)](i) occurred due to influx of calcium from the culture medium. These data provided some novel clues to explain the mechanisms involved in the photo-induced cytotoxicity of fullerene derivatives.