Objective To investigate the molecular function of splicing factor SRSF6 in colorectal cancer (CRC) progression and discover candidate chemicals for cancer therapy through targeting SRSF6.
Design We performed comprehensive analysis for the expression of SRSF6 in 311 CRC samples, The Cancer Genome Atlas and Gene Expression Omnibus (GEO) database. Functional analysis of SRSF6 in CRC was performed in vitro and in vivo. SRSF6-regulated alternative splicing (AS) and its binding motif were identified by next-generation RNA-sequencing and RNA immunoprecipitation sequencing (RIP-seq), which was validated by gel shift and minigene reporter assay. ZO-1 exon23 AS was investigated to mediate the function of SRSF6 in vitro and in vivo. Based on the analysis of domain-specific role, SRSF6-targeted inhibitor was discovered de novoby virtual screening in 4855 FDA-approved drugs and its antitumour effects were evaluated in vitroand in vivo.
Results SRSF6 was frequently upregulated in CRC samples and associated with poor prognosis, which promoted proliferation and metastasis in vitro and in vivo. We identified SRSF6-regulated AS targets and discovered the SRSF6 binding motif. Particularly, SRSF6 regulates ZO-1 aberrant splicing to function as an oncogene by binding directly to its motif in the exon23. Based on the result that SRSF6 RRM2 domain plays key roles in regulating AS and biological function, indacaterol, a β2-adrenergic receptor agonist approved for chronic obstructive pulmonary disease treatment, is identified as the inhibitor of SRSF6 to suppress CRC tumourigenicity.
Conclusions SRSF6 functions the important roles in mediating CRC progression through regulating AS, and indacaterol is repositioned as an antitumour drug through targeting SRSF6.
Accession numbers The accession numbers for sequencing data are SRP111763 and SRP111797.
- colorectal cancer
- alternative splicing
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Contributors Conceptualisation: HZ and ML; methodology: LW, WY, ES and WS; investigation: LW, YL, JK, FH, LZ, TY, YZ and SX; resources: WY, ES, WS, YW and EX; writing-original draft: HZ and LW; writing-review and editing: HZ and ML; supervision: HZ and ML; funding acquisition: HZ and ML.
Funding This work is supported by grants from the National Natural Science Foundation of China (81672730 to HZ and 81572716 to ML), the 111 Project (B13026 to ML) and the Fundamental Research Funds for the Central Universities (172210271 to HZ).
Competing interests None declared.
Ethics approval The protocols (2015027) were approved by the Review Board of Zhejiang University.
Provenance and peer review Not commissioned; externally peer reviewed.