Phenothiazines and calmodulin (review).
The cytotoxic properties of the phenothiazines suggest the potential of phenothiazines as antitumor drugs. The following are some important characteristics of phenothiazines for antitumor research: (i) Phenothiazines show an inherent cytotoxicity which can be utilized in the treatment of tumors. (ii) Selective concentration of phenothiazines in tissues such as melanoma and brain tumors can be utilized in the treatment of such tumors. (iii). Structural modifications of phenothiazines with the substitution of a nitrogen atom may lead to more potent cytotoxic agents, particularly when used in combination with radiation. (iv) A synergic effect may be achieved when phenothiazines are used in combination with other agents and conditions. (v) More research is required for understanding the molecular mechanisms responsible for the cytotoxicity of phenothiazines. (vi) Phenothiazines seem to show both antitumor as well as anticarcinogenic properties. The latter property may be utilized in preventing the formation of tumors as well as in the treatment of tumors at very early stages of their development.