Triple-negative breast cancer (TNBC) is associated with a high mortality rate, which is related to the insufficient number of appropriate biomarkers and targets. Therefore, there is an urgent need to discover appropriate biomarkers and targets for TNBC. SARNP (Hcc-1 and CIP29) is highly expressed in several cancers. It binds to UAP56, an RNA helicase component of the TREX complex in messenger RNA (mRNA) splicing and export. However, the role of SARNP in mRNA splicing and export and in the progression of breast cancer, especially of TNBC, remains unknown. Therefore, we examined the role of SARNP in mRNA splicing and export and progression of TNBC. We confirmed that SARNP binds to UAP56 and Aly and that SARNP overexpression enhances mRNA splicing, whereas its knockdown suppressed mRNA export. The SARNP overexpression induced the proliferation of MCF7 cells, whereas its knockdown induced E-cadherin expression and downregulated vimentin and N-cadherin expressions in SK-BR-3 and MDA-MB-231 cells. SARNP downregulates E-cadherin expression by interaction with pinin. Mice injected with MDA-MB-231shSARNP cells exhibited a significant reduction in tumor growth and lung metastasis compared with those injected with MDA-MB-231shCon cells in vivo. These findings suggested that SARNP is involved in mRNA splicing and export. SARNP maintains mesenchymal phenotype by escaping from inhibitory interaction with pinin leading to the downregulation of E-cadherin expression.
Bibliographical noteFunding Information:
This study was supported by grants from the Basic Science Research Program, through the NRF (NRF‐2016R1E1A2A01953894, NRF‐2017R1A2A1A05000878, NRF‐2017M3A9A 8025606 and NRF‐2018R1A5A2023127) and the research program of Dongguk University, 2017 (Dongguk 2017).
- epithelial–mesenchymal transition
- mesenchymal phenotype
- triple-negative breast cancer
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't