Downregulation of SELENBP1 enhances oral squamous cell carcinoma chemoresistance through KEAP1-NRF2 signaling.

Abstract

PURPOSE:

Limited value is achieved in systemic chemotherapy for oral squamous cell carcinoma (OSCC), due to cancer cell resistance against cytotoxic agents. Tumor suppressor activities of selenium-binding protein 1 (SELENBP1) have been shown in multiple human cancers except for OSCC. The aim of this study is to clarify the biological functions and potential mechanism of SELENBP1 in OSCC.

METHODS:

SELENBP1 expression and its clinical significance in OSCC were analyzed from The Cancer Genome Atlas (TCGA) database. Quantitative polymerase chain reaction (qPCR) or western blot was applied to determine SELENBP1, NRF2 and KEAP1 mRNA or protein levels. Sulforhodamine B assay (SRB) was performed to examine the cytotoxic effects of 5-fluorouracil (5-FU) and cisplatin on OSCC cells. Luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay were conducted to investigate the role of SELENBP1 in KEAP1 transcription.

RESULTS:

SELENBP1 downregulation is positively correlated with a poor prognosis for OSCC patients. SELENBP1 knockdown enhances resistance of OSCC cells to 5-FU and cisplatin, while SENENBP1 overexpression displays the opposite effects. Mechanistically, SELENBP1 reduces NRF2 protein levels by promoting its polyubiquitination and degradation. SELENBP1 induces KEAP1 transcription by binding to KEAP1 promoter. Downregulation of SELENBP1 is induced by miR-4786-3p binding to the 3' untranslated region (UTR) of SELENBP1.

CONCLUSION:

SENENBP1 is identified as a novel protective biomarker for OSCC patients. Targeting at the miR-4786-3p-SELENBP1-KEAP1-NRF2 signaling axis may enhance the efficacy of chemotherapy for OSCC.

• Authors: Hui Zeng, Xubing Zhao, Chengfang Tang
• Journal: Cancer chemotherapy and pharmacology (Cancer Chemother Pharmacol) Vol. 88 Issue 2 Pg. 223-233 (08 2021) ISSN: 1432-0843 [Electronic] Germany
• PMID: 33907880 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 3' Untranslated Regions
• KEAP1 protein, human
• Kelch-Like ECH-Associated Protein 1
• NF-E2-Related Factor 2
• NFE2L2 protein, human
• SELENBP1 protein, human
• Selenium-Binding Proteins
• Cisplatin
• Fluorouracil

Topics

• 3' Untranslated Regions (genetics)
• Carcinoma, Squamous Cell (drug therapy, genetics)
• Cell Line, Tumor
• Cisplatin (pharmacology)
• Down-Regulation (genetics)
• Drug Resistance, Neoplasm (genetics)
• Fluorouracil (pharmacology)
• Genes, Tumor Suppressor (physiology)
• Humans
• Kelch-Like ECH-Associated Protein 1 (genetics)
• Mouth Neoplasms (drug therapy, genetics)
• NF-E2-Related Factor 2 (genetics)
• Selenium-Binding Proteins (genetics)
• Signal Transduction (genetics)