Potential therapeutic uses of rexinoids

Area of Science:

• Immunology
• Molecular Biology
• Pharmacology

Background:

• Nuclear receptors, particularly retinoid X receptors (RXR), are implicated in development and have emerging immunomodulatory roles.
• Genetic models and small molecule modulators (agonists/antagonists) highlight RXR's therapeutic potential in immunology.
• Bexarotene, an RXR agonist, is approved for cutaneous T cell lymphoma; other agonists are in preclinical development.

Purpose of the Study:

• To review the immunomodulatory effects of RXR and its potential as a therapeutic target for cancer and other diseases.
• To explore the role of RXR and partner receptors in immune cells within the tumor microenvironment.
• To assess the potential of combining RXR-targeting small molecules with immune checkpoint inhibitors.

Main Methods:

• Review of existing literature on RXR function in immune cells (T cells, dendritic cells, macrophages) and epithelial cells.
• Analysis of genetic models (deletion/overexpression) of RXR.
• Examination of preclinical data for small molecule RXR agonists and antagonists.

Main Results:

• RXR plays essential roles in immune cells, particularly within the tumor microenvironment.
• RXR targeting generally skews immune cells towards an anti-inflammatory and anti-tumor effect, dependent on cancer type and site.
• Rexinoids show promise in combination with checkpoint inhibitors to improve efficacy and overcome resistance.

Conclusions:

• Targeting RXR nuclear receptors represents a promising strategy for immunomodulation in cancer and chronic inflammatory diseases.
• Small molecule RXR agonists offer a potential therapeutic avenue, particularly when combined with existing immunotherapies.
• Further development of RXR-targeting therapies could enhance treatment outcomes for a range of conditions.