Growth-phase-dependent binding of hematoporphyrin derivative to human glioblastoma (U-87MG) cells

Studies on the binding of hematoporphyrin derivative (HpD) to asynchronous and synchronized human glioblastoma (U-87MG) cells were performed using fluorescence spectroscopy. Cell-bound HpD exhibited three fluorescence bands. The intensity distribution of fluorescence spectrum was found to be depende...

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Bibliographic Details
Published in:	Current science (Bangalore) 1994-11, Vol.67 (9/10), p.740-744
Main Authors:	Sreenivasan, Rajesh, Joshi, Preeti G., Joshi, Nanda B.
Format:	Article
Language:	eng
Subjects:	Cell cycle Cell division Cell growth Cell lines Cell membranes CHO cells Cultured cells Fluorescence Hematoporphyrins Photosensitivity RESEARCH COMMUNICATIONS
Online Access:	Get full text
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Summary:	Studies on the binding of hematoporphyrin derivative (HpD) to asynchronous and synchronized human glioblastoma (U-87MG) cells were performed using fluorescence spectroscopy. Cell-bound HpD exhibited three fluorescence bands. The intensity distribution of fluorescence spectrum was found to be dependent on the growth phase of cells. The relative intensity of 636 nm band increased as the cells progressed through the growth curve. A more distinct change was observed when the fluorescence spectrum of Hpd bound to M-phase cells was compared with G1-phase cells. M-phase cells exhibited maximum fluorescence emission at 615 nm, with a small shoulder at 636 nm whereas in G1-phase cells the 636 nm fluorescence band showed enhancement. HpD binding to synchronized cells was also studied during the cell division cycle. A clear variation in the intensity ratio of 636 to 615 nm fluorescence bands was observed along the cell division cycle. This intensity ratio was maximum in mid G1 and early G2 phases of growth, whereas a minimum was observed in mid S phase. The photosensitivity of asynchronous as well as synchronized cells was determined under above-mentioned experimental conditions. The photosensitivity also varied with the growth phase of the cells. A good correlation was found between the photosensitivity and the fluorescence intensity distribution of cell-bound HpD.
ISSN:	0011-3891