Photodynamic effect of haematoporphyrin throughout the cell cycle of the human cell line NHIK 3025 cultivated in vitro

Abstract

Summary.-Cells from the established cell line NHIK 3025 were synchronized by repeated mitotic selections. Survival of the synchronized cells after treatment with haematoporphyrin and near-UV light was measured by testing the capacity of the cells to form macroscopic colonies.The sensitivity to photodynamic inactivation was small in early G1, late S and G2. The sensitivity increased throughout late G1 and early S to a maximum in mid S. More than a 100-fold variation is found in the survival after 20 min irradiation in the presence of 4 x 10-4M haematoporphyrin.

The mechanism of photodynamic inactivation of human cells in vitro in the presence of haematoporphyrin

“…The photodynamic effect of HP on NHIK 3025 cells is cell-cycle dependent, as previously shown (Christensen et al, 1979). The cell-cycle variation of the efficiency of photodynamic inactivation resembles that of inactivation by hyperthermia, except that in the latter case a drop in the sensitivity is found during the first hours of G1 (Kim et al, 1976;Dewey et al, 1977).…”

Induction of Multinucleated Cells Caused by UVA Exposure in Different Stages of the Cell Cycle

“…Our results are, however, similar to those obtained for NHIK 3025 cells exposed to photosensitizer and light, where G 1 cells were the most resistant and cells in S and G 2 phases were most sensitive (22). Photodynamic treatment acts via the formation of reactive-oxygen species (22). It is well known that UVA irradiation generates reactive-oxygen species (27)(28)(29)(30), and it is likely that such products are responsible for the lethal effect of UVA.…”

“…Cells in the mid-G 1 phase appear to be least sensitive, and those in the mid-G 2 phase appear to be most sensitive toward the lethal effect of UVA. Cell cycle differences in survival after exposure to a number of different agents have been described in the literature (22)(23)(24)(25)(26), but as far as we know no information exists about cell cycle differences in the sensitivity of cells to UVA irradiation. Our results are, however, similar to those obtained for NHIK 3025 cells exposed to photosensitizer and light, where G 1 cells were the most resistant and cells in S and G 2 phases were most sensitive (22).…”

Flow Cytometric Analysis of Intracellular Hematoporphyrin Derivative in Human Tumor Cells and Multicellular Spheroids

“…It has been shown that for some cell lines, G1 cells are the most resistant of cells in the cell cycle to photodynamic treatment (Christensen et al, 1981). However, it should be noted that the same group proposed earlier that variations found through the cell cycle for hematoporphyrin may not be caused by differences in its cellular uptake (Christensen et al, 1979). Nevertheless Gomer and Smith (1980) reported the absence of cell cycle effects suggesting the possibility of cellline dependent differences for cell age response.…”