Ribosomal S6 protein kinase 4 promotes radioresistance in esophageal squamous cell carcinoma.

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Date: Aug. 2020
From: Journal of Clinical Investigation(Vol. 130, Issue 8)
Publisher: American Society for Clinical Investigation
Document Type: Article
Length: 11,990 words
Lexile Measure: 1450L

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Abstract :

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive cancers and is highly resistant to current treatments. ESCC harbors a subpopulation of cells exhibiting cancer stem-like cell (CSC) properties that contribute to therapeutic resistance including radioresistance, but the molecular mechanisms in ESCC CSCs are currently unknown. Here, we report that ribosomal S6 protein kinase 4 (RSK4) plays a pivotal role in promoting CSC properties and radioresistance in ESCC. RSK4 was highly expressed in ESCC CSCs and associated with radioresistance and poor survival in patients with ESCC. RSK4 was found to be a direct downstream transcriptional target of [DELTA]Np63[alpha], the main p63 isoform, which is frequently amplified in ESCC. RSK4 activated the [beta]-catenin signaling pathway through direct phosphorylation of GSK-3[beta] at Ser9. Pharmacologic inhibition of RSK4 effectively reduced CSC properties and improved radiosensitivity in both nude mouse and patient-derived xenograft models. Collectively, our results strongly suggest that the [DELTA]Np63[alpha]/RSK4/GSK-3[beta] axis plays a key role in driving CSC properties and radioresistance in ESCC, indicating that RSK4 is a promising therapeutic target for ESCC treatment.

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Gale Document Number: GALE|A633717396