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Antineoplastic Agents The main goal of antineoplastic agents is to eliminate the cancer cells without affecting normal tissues (the concept of differential sensitivity). In reality, all cytotoxic drugs affect normal tissues as well as malignancies - aim for a favorable therapeutic index (aka therapeutic ratio). Two Major Classes Cancer Chemotherapy Chapter 55. B.G. Katzung
Cell Cycle and Cancer. Normal and Cancer cells must traverse before and during cell division. Differentiation 2% Synthesis of cellular Components needed For Mitosis 19% Synthesis of cellular Components needed For DNA synthesis. Replication of DNA genome 40% 39% Cancer Chemotherapy Chapter 55. B.G. Katzung
Cancer Chemotherapy Chapter 55. B.G. Katzung
Alkylating Agents: General Mechanism of Action E.g., Mechlorethamine (Nitrogen Mustards) Cancer Chemotherapy Chapter 55. B.G. Katzung
Cyclophosphamide (Alkylating agent) Inactive Aldophosphamide 4-Hydroxycyclophamide Breast, ovarian, CLL, soft tissue sarcoma, WT, neuroblastoma Cancer Chemotherapy Chapter 55. B.G. Katzung
Summary Cancer Chemotherapy Chapter 55. B.G. Katzung
B. Natural Products 1. Antimitotic Drugs 2. Antimitotic Drugs
3. Epipodophyllotoxins (These are CCS) Act on Topoisomerase II Accumulation of single- or double-strand DNA breaks, the inhibition of DNA replication and transcription, and apoptotic cell death. Etoposide acts primarily in the G2 and S phases of the cell cycle
4. Antibiotics Cancer Chemotherapy Chapter 55. B.G. Katzung
5. Enzymes: L-asparaginase Cancer Chemotherapy Chapter 55. B.G. Katzung
C. Antimetabolites (Folic acid analog) MTX polyglutamates Are selectively retained In tumor cells. Folic acid is an essential dietary factor, from which THF cofactors are formed which provide single carbon groups for the synthesis of precursors of DNA and RNA. To function as a cofactor folate must be reduced by DHFR to THF. Reduced Folate Carrier protein Methotrexate Kills cells during S-phase Cancer Chemotherapy Chapter 55. B.G. Katzung