In vitro effects and localisation of the photosensitizers m-THPC and m-THPC MD on carcinoma cells of the human breast (MCF-7) and chinese hamster fibroblasts (V-79)

✍ Scribed by Hornung, R.; Jentsch, B.; Crompton, N. E. A.; Haller, U.; Walt, H.

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 451 KB
• Volume: 20
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/(sici)1096-9101(1997)20:4<443::aid-lsm11>3.0.co;2-c

✦ Synopsis

Background and objective:

Photodynamic therapy (pdt) is the combination of a photosensitizer with laser light to induce preferential destruction of malignant cells. in this study two new photosensitizers--5,10,15,20-meta-tetra(hydroxyphenyl) chlorin (m-thpc) and m-thpc methoxypeg2000 derivative (m-thpc md)--were tested, both for their dark toxicity, i.e., cytotoxicity in the absence of light, and for their light-induced cytotoxicity in mammalian cell cultures.

Study design/materials and methods:

Cell lines used were mcf-7 (human breast carcinoma) and v-79 (chinese hamster lung fibroblast). after cultivation under standard conditions, cells were administered the photosensitizers and 24 hr later exposed to various energy levels of laser light at a wavelength of 652 nm. cell survival was monitored using a clonogenic assay and was expressed as the surviving fraction of the untreated control.

Results:

Up to an m-thpc concentration of 1 microgram/ml, no dark toxicity was observed; at higher concentrations a rapid fall in survival occurred. m-thpc md showed no dark toxicity up to 100 micrograms/ml. in vitro m-thpc was approximately 10 times more cytotoxic than m-thpc md. the mcf-7 and v-79 cell lines displayed similar responses to pdt.

Conclusions:

Both m-thpc and m-thpc md are very efficient photosensitizers in vitro. up to the therapeutic dose, neither exhibited dark toxicity. there is clinical relevance of the photosensitizers by a large therapeutic index.