According to a new study published in the journal Cancer Research, a form of vitamin A called retinoic acid that is used in the treatment of various cancers can be inhibited by a certain protein in some patients.
The astrocyte elevated gene-1 (AEG-1) protein can block the effects of retinoic acid in patients with leukemia and liver cancer. Since AEG-1 is overexpressed in almost every cancer, many patients could be at risk for decreased efficacy with retinoic acid therapy.
According to Devanand Sarkar, MBBS, PhD, of the Massey Cancer Center at Virginia Commonwealth University in Richmond, Virginia, retinoid X receptors (RXR), which are involved with the regulation of cell growth, are activated by retinoic acid, but the overexpressed AEG-1 protein inhibits the activation of RXR, thereby promoting cancer cell proliferation.
By using complex animal models, the investigators found that by inhibiting the production of AEG-1, retinoic acid was able to perform its intended effect, significantly killing liver cancer cells.
Dr. Sarkar and his team say the results from blocking AEG-1 production in combination with retinoic acid therapy have been promising and hope to eventually initiate a phase 1 clinical trial involving patients with liver cancer treated with an AEG-1 inhibitor and retinoic acid.
Retinoic acid is a form of vitamin A that is used to treat and help prevent the recurrence of a variety of cancers, but for some patients the drug is not effective.
The reason for this resistance was unclear until researchers from Virginia Commonwealth University (VCU) Massey Cancer Center demonstrated that a protein known as AEG-1 blocks the effects of retinoic acid in leukemia and liver cancer. Because AEG-1 is overexpressed in nearly every cancer, these findings could impact the care of countless cancer patients.