Knockdown of lecithin retinol acyltransferase increases all‐trans retinoic acid levels and restores retinoid sensitivity in malignant melanoma cells. Issue 11 (10th October 2014)

• Record Type: Journal Article
• Authors: Amann, Philipp M.; Czaja, Katharina; Bazhin, Alexandr V.; Rühl, Ralph; Skazik, Claudia; Heise, Ruth; Marquardt, Yvonne; Eichmüller, Stefan B.; Merk, Hans F.; Baron, Jens M.
• Is Part Of: Experimental dermatology. Volume 23:Issue 11(2014:Nov.)
• Page Start: 832
• Page End: 837
• Publication Date: 2014-10-10
• Subjects: Dermatology -- Periodicals; 616.5
• DOI: 10.1111/exd.12548
• Languages: English
• ISSNs: 0906-6705

Abstract

<abstract abstract-type="main" id="exd12548-abs-0001"> <title>Abstract</title> <p>Retinoids such as all‐<italic>trans</italic> retinoic acid (ATRA) influence cell growth, differentiation and apoptosis and may play decisive roles in tumor development and progression. An essential retinoid‐metabolizing enzyme known as lecithin retinol acyltransferase (LRAT) is expressed in melanoma cells but not in melanocytes catalysing the esterification of all‐<italic>trans</italic> retinol (ATRol). In this study, we show that a stable LRAT knockdown (KD) in the human melanoma cell line SkMel23 leads to significantly increased levels of the substrate ATRol and biologically active ATRA. LRAT KD restored cellular sensitivity to retinoids analysed in cell culture assays and melanoma 3D skin models. Furthermore, ATRA‐induced gene regulatory mechanisms drive depletion of added ATRol in LRAT KD cells. PCR analysis revealed a significant upregulation of retinoid‐regulated genes such as CYP26A1 and STRA6 in LRAT KD cells, suggesting their possible involvement in mediating retinoid resistance in melanoma cells. In conclusion, LRAT seems to be important for melanoma progression. We propose that reduction in ATRol levels in melanoma cells by LRAT leads to a disturbance in cellular retinoid level. Balanced LRAT expression and activity may provide protection against melanoma development and progression. Pharmacological inhibition of LRAT activity could be a promising strategy for overcoming retinoid insensitivity in human melanoma cells.</p> </abstract>