Cell cycle-nonspecific drug

Cell-Cycle-Specific Versus Cell-Cycle-Nonspecific Drugs... 

FIGURE 36-1 T Phases of the cell cycle. Examples of cell-cycle-specific drugs are listed next to the phase of the cycle they act on. Examples of cell-cycle-nonspecific drugs are listed below the figure. See text for more details. 

Information on cell and population kinetics of cancer cells explains, in part, the limited effectiveness of most available anticancer drugs. A schematic summary of cell cycle kinetics is presented in Figure 54-2. This information is relevant to the mode of action, indications, and scheduling of cell cycle-specific (CCS) and cell cycle-nonspecific (CCNS) drugs. Agents falling into these two major classes are summarized in Table 54-1. 

Drugs acting on nonproliferating cells are cell-cycle nonspecific (CCNS)—dose-dependent. 

Drugs that are cell-cycle nonspecific (many bind to and damage DNA) can be used in tumors with low-growth fraction, as well as tumors with high-growth fraction. 

Cell cycle-nonspecific (CCNS) drug An anticancer agent that acts on tumor stem cells when they are traversing the cell cycle and when they are in the resting phase... 

Antineoplastic anthracycUne drug (cell cycle-nonspecific) intercalates between base pairs to disrupt DNA functions, inhibits topoisomerases, and forms cytotoxic free radicals. Tox cardiotoxicity (consider dexrazoxane), myelosuppres.sion. Daunorubicin is similar. 

Phlorizin has been reported to have a marked effect on biliary excretion of BSP and bilirubin it usually increases bile flow, but excretion of both compounds is reduced (J6, S40, V3). The action of this compound may be nonspecific, since it is believed that the drug inhibits the oxidation of all substrates of the tricarboxylic acid cycle (L16) by alteration of the permeability of cell membranes (K5). Phlorizin is also excreted in bile (S34), and its choleretic action is possibly due to the osmotic effect of excretion of this organic anion. 

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