Rosenthal I, Murali Krishna C, Riesz P, Ben-Hur E
Radiat Res. 1986 Jul;107(1):136-42.
Phthalocyanines are a class of mammalian cell photosensitizers which may be useful in photodynamic therapy for cancer. Chloroaluminum phthalocyanine tetrasulfonate was incubated with Chinese hamster cells in culture and exposed to white light at different concentrations of oxygen. The ability of the cells to form colonies served as an end point for the photobiological effect of the dye. The efficiency of photoinactivation of the sensitized cells decreased with decreasing oxygen concentration. Very little photoinactivation was observed when the atmosphere equilibrated with the cells was oxygen-free nitrogen. At an oxygen partial pressure of 2.5 mm Hg, photoinactivation was reduced by 50% compared to ambient atmosphere. In an attempt to understand the nature of the interaction between excited dyes and oxygen, the ability of several phthalocyanines to photogenerate singlet oxygen was measured. Thus phthalocyanines containing paramagnetic ions (copper, iron, vanadyl) do not generate 1O2 in contradistinction to diamagnetic metals (zinc and aluminum). The latter are efficient photosensitizers, while the former have little if any photobiological activity. In spite of this correlation, singlet oxygen may not be the intermediate involved in cytotoxicity. The reasons are discussed.
酞菁是一类哺乳动物细胞光敏剂，可能在癌症的光动力治疗中有用。将四磺酸氯铝酞菁与培养中的中国仓鼠细胞一起孵育，并在不同氧气浓度下暴露于白光。细胞形成集落的能力作为染料光生物学效应的终点。随着氧气浓度降低，致敏细胞的光灭活效率降低。当与细胞平衡的气氛是无氧氮气时，观察到的光灭活很少。在氧分压为2.5毫米汞柱时，与周围大气相比，光灭活降低了50%。为了了解激发染料与氧气之间相互作用的性质，测量了几种酞菁产生单线态氧的能力。因此，含有顺磁性离子（铜、铁、氧钒基）的酞菁与抗磁性金属（锌和铝）不同，不会产生1O2。后者是有效的光敏剂，而前者几乎没有光生物学活性。尽管有这种相关性，但单线态氧可能不是细胞毒性所涉及的中间体。讨论了其原因。
