aGenome-scale activation screen reveals lncRNA HNF1A-AS1 promotes pancreatic cancer metastasis through interacting with U2SURP to increase CD44 alternative splicing.

Background: Pancreatic cancer (PC) has a strong ability to invade and metastasize, which has brought insurmountable obstacles to the treatment of PC. Exploring the molecular mechanism of PC metastasis is still the focus of PC research. The purpose of this study was to explore the molecular mechanism of long noncoding RNA HNF1A-AS1 in promoting PC metastasis, hoping to provide help for the diagnosis and treatment of PC.

Methods: CRISPR/CRISPR-associated protein 9 (Cas9) single-guide RNA (sgRNA)-pooled lncRNA libraries were used to screen for the critical lncRNAs regulating PC metastasis. Investigation into HNF1A-AS1's impact on PC cell migration and invasion were conducted through both loss-of-function and gain-of-function approaches. A range of techniques, including fluorescence in situ hybridization (FISH), mRNA sequencing, bioinformatics analysis, dual-luciferase reporter assays, RNA pull-down assays, ChIP-PCR, and rescue assay to explore the regulatory mechanism of HNF1A-AS1 in PC metastasis.

Results: SNAI2 activates HNF1A-AS1 transcription. HNF1A-AS1 recruits U2SURP (RRM-dependent domain-dependent) through the 1001-1500 nt region (BR3) to form a functional complex (SNAI2-lncRNA HNF1A-AS1-U2SURP) within the nucleus of PC cells, specifically promoting alternative splicing of CD44 pre-mRNA, transforming it from standard isoform CD44s-CD44v (3-10) isoform, thereby promoting PC invasion and metastasis.

Conclusions: This study revealed for the first time that SNAI2 activates the transcription of HNF1A-AS1, and HNF1A-AS1 promote U2SURP to regulate the alternative splicing of CD44 pre-mRNA, causing it to produce a large number of CD44v (3-10) isoforms, thereby promoting the invasion and metastasis of PC.