Multidrug Resistance in Breast Cancer: From In Vitro Models to Clinical Studies

Table 2

Chemotherapy agents used to treat breast cancer subject to MDR.

Class of drug	Drug	Clinical use	Mechanism of action
Anthracyclines	Doxorubicin	Leukaemias, Hodgkin’s Lymphoma, bladder, breast, stomach, lung, ovarian, thyroid, soft tissue sarcomas, multiple myeloma and more	Acts by intercalating DNA, resulting in complex formation which inhibits DNA and RNA synthesis. Triggers DNA cleavage by topoisomerase II resulting in cell death
	Epirubicin	Breast, ovarian, gastric, lung, and lymphomas	Acts by intercalating DNA
Taxanes	Paclitaxel	Ovarian, breast, lung and Kaposi’s sarcoma	Mitotic inhibitor; interferes with the normal function of microtubule breakdown. Also induces apoptosis
	Docetaxel	Ovarian, breast and lung	Interferes with microtubule breakdown
Vinca Alkaloids	Vinblastine	Hodgkin’s Lymphoma, lung, breast, head and neck and testicular	It binds tubulin, thereby inhibiting the assembly of microtubules
Anti-metabolites	5-Fluorouracil	Breast, head and neck, stomach, colon and some skin cancers	Metabolised to cytotoxic metabolites which are incorporated into DNA and RNA, inducing cell cycle arrest and apoptosis
	Methotrexate	Leukaemia, breast, skin, head and neck and lung	Inhibits metabolism of folic acid. Acts specifically during DNA and RNA synthesis, and thus it is cytotoxic during the S-phase of the cell cycle
Anthracenediones	Mitoxantrone	Breast, Leukaemia, Non-Hodgkin’s Lymphoma and Prostate	Topoisomerase II inhibitor; disrupts DNA synthesis and DNA repair