Retinoic acid metabolism blocking agents (RAMBAs) for treatment of cancer and dermatological diseases

Bioorg Med Chem. 2006 Jul 1;14(13):4323-40. doi: 10.1016/j.bmc.2006.02.041. Epub 2006 Mar 10.


The naturally occurring retinoids and their synthetic analogs play a key role in differentiation, proliferation, and apoptosis, and their use/potential in oncology, dermatology and a variety of diseases are well documented. This review focuses on the role of all-trans-retinoic acid (ATRA), the principal endogenous metabolite of vitamin A (retinol) and its metabolism in oncology and dermatology. ATRA has been used successfully in differentiated therapy of acute promyelocytic leukemia, skin cancer, Kaposi's sarcoma, and cutaneous T-cell lymphoma, and also in the treatment of acne and psoriasis. However, its usefulness is limited by the rapid emergence of acquired ATRA resistance involving multifactoral mechanisms. A key mechanism of resistance involves ATRA-induced catabolism of ATRA. Thus, a novel strategy to overcome the limitation associated with exogenous ATRA therapy has been to modulate and/or increase the levels of endogenous ATRA by inhibiting the cytochrome P450-dependent ATRA-4-hydroxylase enzymes (particularly CYP26s) responsible for ATRA metabolism. These inhibitors are also referred to as retinoic acid metabolism blocking agents (RAMBAs). This review highlights development in the design, synthesis, and evaluation of RAMBAs. Major emphasis is given to liarozole, the most studied and only RAMBA in clinical use and also the new RAMBAs in development and with clinical potential.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Animals
  • Antineoplastic Agents / chemistry*
  • Antineoplastic Agents / therapeutic use
  • Cytochrome P-450 Enzyme Inhibitors*
  • Cytochrome P-450 Enzyme System / metabolism
  • Dermatologic Agents / chemistry*
  • Dermatologic Agents / therapeutic use
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / therapeutic use
  • Humans
  • Neoplasms / drug therapy*
  • Neoplasms / enzymology
  • Retinoic Acid 4-Hydroxylase
  • Skin Diseases / drug therapy*
  • Skin Diseases / enzymology
  • Tretinoin / metabolism*
  • Tretinoin / therapeutic use


  • Antineoplastic Agents
  • Cytochrome P-450 Enzyme Inhibitors
  • Dermatologic Agents
  • Enzyme Inhibitors
  • Tretinoin
  • Cytochrome P-450 Enzyme System
  • Retinoic Acid 4-Hydroxylase