Sreenivasan R, Muruganandham M, Sharma M, Joshi P G, Joshi N B
Department of Biophysics, National Institute of Mental Health and Neurosciences, Bangalore, India.
Cancer Lett. 1997 Nov 25;120(1):45-51. doi: 10.1016/s0304-3835(97)00290-5.
The binding of monomeric (Hp) and oligomeric (PHE) forms of porphyrin to glioblastoma (U-87MG) cells and the photosensitization of these cells have been studied. Upon binding to U-87MG cells, Hp and PHE exhibited fluorescence bands at 615 and 636 nm, respectively. The fluorescence and absorption spectra of Hp, HpD and PHE, measured in different solvents, suggest that the 615 nm band may arise due to the binding of monomeric as well as aggregated forms of porphyrin to the hydrophilic sites in the cells whereas the 636 nm band may be due to the binding of an aggregated form of porphyrin to the hydrophobic sites. The photosensitivity of cells and photo-induced lipid peroxidation were measured as a function of light dose. Cells were found most photosensitive to PHE followed by HpD and Hp. The photosensitivity of cells correlates well with the fluorescence intensity of cell bound dye at 636 nm. These results suggest that the binding of the oligomeric component of HpD to hydrophobic sites in the cells is responsible for the enhancement in the photosensitivity.
已对卟啉的单体形式（Hp）和寡聚体形式（PHE）与胶质母细胞瘤（U - 87MG）细胞的结合以及这些细胞的光致敏作用进行了研究。与U - 87MG细胞结合后，Hp和PHE分别在615和636 nm处呈现荧光带。在不同溶剂中测量的Hp、HpD和PHE的荧光光谱和吸收光谱表明，615 nm处的谱带可能是由于卟啉的单体形式以及聚集形式与细胞中的亲水位点结合所致，而636 nm处的谱带可能是由于卟啉的聚集形式与疏水位点结合所致。测量了细胞的光敏性和光诱导的脂质过氧化作用与光剂量的关系。发现细胞对PHE最敏感，其次是HpD和Hp。细胞的光敏性与细胞结合染料在636 nm处的荧光强度密切相关。这些结果表明，HpD的寡聚体成分与细胞中疏水位点的结合导致了光敏性的增强。
