Zyxin cooperates with PTOV1 to confer retinoic acid resistance by repressing RAR activity

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Retinoids, including all-trans retinoic acid (RA), are utilized in cancer therapy.
• Acquired resistance to RA therapy is a significant clinical challenge, with underlying mechanisms not fully understood.

Purpose of the Study:

• To identify novel regulators of all-trans retinoic acid (RA) signaling involved in cancer therapy resistance.
• To elucidate the molecular mechanism by which Zyxin and PTOV1 negatively regulate RA signaling.

Main Methods:

• Identification of Zyxin as a novel interacting protein with PTOV1.
• Investigation of Zyxin's nuclear translocation in response to RA.
• Analysis of the formation of a ternary complex involving Zyxin, PTOV1, and CBP (a coactivator of RAR).
• Assessment of the impact of Zyxin and PTOV1 on RA-responsive promoter activity and RA-induced cancer cell cytotoxicity.

Main Results:

• Zyxin was identified to cooperate with PTOV1 in the negative regulation of RA signaling.
• RA treatment induced nuclear translocation of Zyxin.
• Zyxin formed a ternary complex with PTOV1 and CBP, leading to the dissociation of CBP from RAR at RA-responsive promoters.
• Overexpression of Zyxin or PTOV1 significantly impaired RA-induced cancer cell cytotoxicity.

Conclusions:

• Zyxin and PTOV1 act as critical negative regulators of RA signaling.
• These proteins contribute to acquired resistance in RA-based cancer therapy.
• Targeting Zyxin and PTOV1 may represent a therapeutic strategy to overcome retinoid resistance in cancer treatment.