P-glycoprotein: so many ways to turn it on

J Clin Pharmacol. 2008 Mar;48(3):365-78. doi: 10.1177/0091270007311568. Epub 2007 Dec 21.


Expression of the ABC transporter P-glycoprotein (P-gp or ABCB1) is associated with resistance to chemotherapy in cancer. However, early investigations into the regulation of ABCB1 expression revealed that the process is not a classical induction as observed for certain metabolizing enzymes. The process involves the cellular stress response pathway initiated by either inflicted (e.g., chemotherapy damage) or endogenous (e.g., hypoxia) factors. However, ABCB1 is also expressed in a number of noncancerous tissues. In particular, the protein is found at tissues providing a barrier or secretory function. The localization of ABCB1 in normal tissues will impact significantly on drug pharmacokinetics, in particular the absorption and elimination processes. This review also describes the mechanism underlying ABCB1 expression in noncancerous tissue, a process that does not involve the stress response.

Publication types

  • Review

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / metabolism*
  • Animals
  • Cytochrome P-450 CYP3A / metabolism
  • Cytochrome P-450 Enzyme System / metabolism*
  • Drug Resistance, Neoplasm*
  • Humans
  • Models, Biological
  • Signal Transduction


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Cytochrome P-450 Enzyme System
  • Cytochrome P-450 CYP3A