Anti-cancer drugs Flashcards
(19 cards)
Cancer
Diseases in which abnormal cells divide without control and are able to invade other tissues.
Cancer types (6)
- Carcinoma - skin or tissues that cover organs (epithelial)
- Sarcoma - fat, muscle cartilage, bone, blood vessels etc.
- Leukemia - White blood cells and their pre-cursor cells
- Lymphoma - cells of the immune system.
- Myeloma - B cells that produce cancerous antibodies
- Central nervous system - cancers that begin in the tissues of the brain and spinal chord.
Cancer therapeutics
Surgery (60%), radiation (50%) and chemotherapy(12.5%)
Chemotherapy
Given in doses to minimalize the toxicity to normal cells, in cyclic regimens, often associated with therapeutic drugs to ease recovery.
Adjuvant therapy vs neoadjuvant therapy
Adjuvant therapy is additional cancer treatment given after primary treatment to lower risk that the cancer will return, while neoadjuvant therapy is given as a first step to reduce the tumor size before surgery.
Chemotherapy types (4)
- Antimetabolites - Drugs that interfere with formation of biomolecules
- Genotoxic drugs - Drugs that alkylate or intercalate the DNA causing the loss of its function.
- Plant derived inhibitors - prevent cell division by interfering with the cytoskeletal components that enable the cell to divide.
- Plant derived topoisomerase - unwind or regulate DNA during replication.
Antimetabolites types
Antifolates - such as methotrexate
Purine antimetabolites - 6-thioguanine
Pyrimidine antagonists - 5-fluorouracil
Mode of action of alkylating agents
Stop tumor growth by cross linking guanine in DNA bases, destroying double helix shape. Stops strands from separating. However, these drugs can be cancerous themselves.
Commonly used alkylating agent
Cyclophosphamide, given orally or intravenously. It must be activated by the liver CYT450 enzyme.
Side effects of Cyclophosphamide
(Used in WW1 as mustard gas)
Nausea and vomiting
PBL count decrease
Decrease in blood pressure
Alopecia
Skin pigmentation
Pulmonary fibrosis
Mode of action of plant derived inhibitors
Composed of the alpha and beta subunits, these polymerize and depolymerize microtubules, which are essential in mitosis. This causes cell cycle arrest.
Commonly used plant derived inhibitors
Vinca alkaloids, such as vincristine and vinblastine, or paclitaxel.
Mode of action of topoisomerase inhibitors
Topoisomerases are needed to cutting and re-annealing DNA during mitosis, inhibiting their action commits cell cycle arrest.
Other anti-cancer agents
Antibiotics such as Dactinomycin, it inhibits DNA directed RNA synthesis. Stops guanine colating.
Hormonal treatments of cancer
Estrogen receptor is overexpressed in 70% of breast cancer cases. Anti-estrogen therapies such as tamoxifen can be implicated to inhibit breast cancer.
Side effects of tamoxifen
CNS depression
Light-headedness
Decreased activity
Nausea
Vomiting
Specific inhibitors for cancer therapies examples.
Proteasome is the unit for degradation of damaged or misfolded proteins. Inhibiting proteasome promotes apoptosis inducing factor Bax. The accumulation of Bax leads to apoptosis of cancer cells.
Bortezomib is an example of proteasome inhibitor.
Monoclonal antibodies to treat cancer (3)
- Bind to cancer specific antigens and induce immunological response such as induced apoptosis.
- Can be modified to bind to cancer cell and deliver a synthesized, or manually-bound toxin.
- Can be designed to bind to antigen and the conjugate (effector) cell.
Example of Mab cancer therapy
HER2 (Trastuzumab) can be used to treat breast cancer. HER2 releases signaling molecules when cell proliferation, motility or resisting apoptosis is discovered. these cells are then marked for destruction by the HER2 markers.
