General concepts / Cell cycle specificity
CELL CYCLE SPECIFICITY
Cell cycle was presented by Dr. Holy in Foundations.
Cancer drugs can be divided into two general classes: CELL CYCLE SPECIFIC DRUGS (CCS; esp. plant alkaloids and antimetabolites), and CELL CYCLE NON-SPECIFIC DRUGS (CCNS; esp. alkylating agents and some natural products). Antineoplastic agents can also be organized according to their chemical class, mechanism of action, therapeutic use or their toxicities. | ![]() |
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all cells (normal and neoplastic) progress through the cell cycle
- cells spend a different percentage of time in each portion of the cell cycle
- the percentages indicated in the figure are typical for a neoplastic cell
- in particular, the duration of both G0 and G1 can vary dramatically
drugs that act only during a specific portion of the cell cycle (CCS drugs) will be least effective at treating cancers who have low growth fractions (i.e., most of the cells are in G0)
- it is common to follow treatment with a CCNS drug with a CCS drug, so that cancer cells are recruited into the cell cycle, where CCS drugs can be more effective
CELL CYCLE SPECIFIC DRUGS (CCS) |
CELL CYCLE NON-SPECIFIC DRUGS (CCNS) |
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