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42 Cards in this Set

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Cell Stages
G1: RNA and protein synthesis
S: Chromosome replication
G2: rapid growth
M: mitosis
Go: resting phase
Class 1 agents
All cells killed regardless of state of proliferation
e.g. nitrogen mustard, non-specific alkylating agents
Class 2 agents
Cell cycle specific
(*the plateau of its curve represents porportion of cells which have not passed through the sensitive phase)
e.g. vinblastine, methotrexate
Class 3 agents
non-cycle specific-more effective against dividing cells
e.g. cyclophosphamide and daunorubicin
What about a survival curve?
They're logirithmic--a given dose kills a constant fraction of cells
In addition to [] dependence what else is a critical factor.
[]= concentration
Time of exposure to lethal []
Factors affecting chemotherapy
1. Cell cycle kinetics
2. Growth fraction
3. Tumor heterogenicity
4. Tumor size
5. Tumor resistance
Mechanisms of resistance to chemo drugs.
1. Transport defects
2. Somatic mutation (6-thioguanine)
3. Gene amplification (methotrexate)
4. MDR
Multidrug resistance
Overproduction of membrane glycoproteins that actively pump out drugs.
4 strategies of chemo
1. Combine drugs
2. Induction and maintenance
3. Attempts @ cell recruitment
4. Attempts at cell synchronization
5 classes of chemo drugs
I. Alkylating agents- covalently modify DNA

II Natural Products-block/disrupt biochemistry

III Antimetabolites- mimic

IV Enzymes- degradation

V Biological Response Modifiers (BRM)- growth dependent factors
5 principal classes of alkylating agents
1. Nitrogen mustards
2. Ethylenimines
3. Alkylsulfonates
4. Nitrosoureas
5. Triazene
What group do the N-mustards use
Bis-(2-chloroethyl) group
MOA of N-mustards
Alkylate DNA at N-7 of guanine --> breaks and mistakes
Melphalan (Admin/structure/t1/2, PK)
Admin: orally
Structure: derivative of phenylalanine
t1/2: 1.5-2.0 hours
PK: Cellular entry by active transports. Alkylating agent. Excreted in stool and some in urine
Chlorambucil
Alkylating agent similar to melphalan
Cyclophosphamide activation
Must be activated by CYP2C9 to aldophosphamide then hydrolyed @ target cells to active phosphomide mustard
How does the liver play a role in Cyclophosphamide activation
Converts drug into inactive metabolites so that the hepatotoxicity (and other SEs) of nitrogen mustards is reduced or eliminated
Toxicities of Cyclophosphamide
Immunosuppression
Nausea
Vomiting
Cystitis
H20 retention
Alopecia
Carcinogenesis
Ifosfamide: Use and SE
Alkylating agent cyclophosphamide derivative used for testicular cancer

Myelosuppression and urotoxicity
Ethylenimines example-use
Thiotepa
Breast and ovarian cancer
Ex. of an alkylsulfonate
Bulsulfan- a bifunctional methanesulfonate
MOA and PK of Busulfan
MA: Alkylation via methanesulfonate release

PK: Oral admin, rapid absorption, excreted as methanesulfonic acid
Toxicity of Busulfan
Myelosuppression (esp. granulocytopenia), increase pigmentation, pulmonary fibrosis
List the chloroethyl nitrosoureas
BCNU (carmustine)
CCNU (lomustine)
Methyl CCNU (semustine)
What are the chloroethyl nitrosoureas capable of?
Alkylation
DNA crosslinking
Carbamoylation of proteins
What gives the chloroethyl nitrosoureas their long t1/2.
They're lipid soluble (that means the cross the BBB too)
Carmustine has an intresting adminstration? What is it, how do you use it?
Given via an implantable water wafer for malignant glioma.
Toxicities of Chloroethyl nitrosoureas:
Delayed but severe hematopoietic depression
Pulmonary fibrosis
Renal insufficiency
Alopecia
Nausea
Vomiting
Name a methylnitrosourea. What's its use?
Streptozocin~ preferentially acts on pancreatic islet cells
Name 2 Triazenes
Dacarbazine (DTIC)
Temozolomide
DTIC MOA
(-) RNA and protein synthesis--> DNA synthesis because of non-specific alkylation
Toxicities of DTIC
Nausea
Vomiting
Mild myelosuppression
Use and SE of Temozolomide
Used for Anaplastic Astrocytoma

SE: Myelosuppression
Cisplatin (Platinol) contains what? What form is active. Use.
Platinum
Cis-dichloro form
Testicular cancer, ovarian carcinoma, H & N cancers
MOA of Cisplatin
Alkylation achieved by dissocation of Cl-. Crosslinks are then formed (DNA-DNA, DNA-protein)
Pharmacology of Cisplatin
Free platinol cleared by kidneys quickly, but Pt is bound to plasma protein for days; it is inactive
Cisplatin analogue are
Cross-resistant
Toxicities of Cisplatin
Myelosuppression
Nephrotoxicity
Ototoxicity
How do we attenuate the nephrotoxicity caused by Cisplatin
Admin sulfhydryl- containing free radical scavenger, Amifostine
Carboplatin
Also a platinol analogue but has substantially less renal toxicity, still causes leukopenia and thromobocytopenia
Procarbazine- use and toxicity
Non-specific alkylator
Used for Hodgkin's dz
Myelosuppression, carcinogenicity, toxicity w/MAOIs