Targeting truncated RXRα for cancer therapy.
Retinoid X receptor-alpha (RXRα), a unique member of the nuclear receptor superfamily, is a well-established drug target, representing one of the most important targets for pharmacologic interventions and therapeutic applications for cancer. However, how RXRα regulates cancer cell growth and how RXRα modulators suppress tumorigenesis are poorly understood. Altered expression and aberrant function of RXRα are implicated in the development of cancer. Previously, several studies had demonstrated the presence of N-terminally truncated RXRα (tRXRα) proteins resulted from limited proteolysis of RXRα in tumor cells. Recently, we discovered that overexpression of tRXRα can promote tumor growth by interacting with tumor necrosis factor-alpha-induced phosphoinositide 3-kinase and NF-κB signal transduction pathways. We also identified nonsteroidal anti-inflammatory drug Sulindac and analogs as effective inhibitors of tRXRα activities via a unique binding mechanism. This review discusses the emerging roles of tRXRα and modulators in the regulation of cancer cell survival and death as well as inflammation and our recent understanding of tRXRα regulation by targeting the alternate binding sites on its surface.
School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China Sanford Burnham Prebys Medical Discovery Institute, Cancer Center, La Jolla, CA 92037, USA xkzhang@xmu.edu.cn.
Xiaokun
X
Zhang
School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China.
Hu
H
Zhou
School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China Sanford Burnham Prebys Medical Discovery Institute, Cancer Center, La Jolla, CA 92037, USA.
Ying
Y
Su
D000818:Animals; D017209:Apoptosis; D001665:Binding Sites; D002470:Cell Survival; D055808:Drug Discovery; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007249:Inflammation; D008024:Ligands; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D009369:Neoplasms / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D011485:Protein Binding; D000072417:Protein Domains; D055503:Protein Multimerization; D047490:Retinoid X Receptor alpha / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D008024:Ligands; D016328:NF-kappa B; D047490:Retinoid X Receptor alpha; D014409:Tumor Necrosis Factor-alpha; D019869:Phosphatidylinositol 3-Kinases
PI3K; RXRα modulators; inflammation; nongenomic action; tRXRα