Background
Layilin (LAYN) plays an important role in tumor progression, invasion, and metastasis; however, its role in cholangiocarcinoma (CHOL) has not been elucidated.
Conclusion
Our results suggest that CREB1 promotes CHOL metastasis through transcriptional regulation of the LAYN-mediated TLN1/β1 integrin axis.
Methods
We utilized the GEPIA, STRING, and hTFtarget databases for bioinformatics analysis. Overexpression or knockdown cell lines were constructed by transfecting the cells with different plasmids. Western blot (WB) was performed to detect LAYN, TLN1, and CREB1 expression. Cell proliferation, migration, and invasiveness were assessed using CCK-8 and Transwell assays. Immunofluorescence and WB were used to detect epithelial-mesenchymal transition (EMT) markers. The CHOL metastasis model was established by injecting RBE cells into the tail veins of nude mice. Metastatic lesions were identified using hematoxylin and eosin staining. Co-immunoprecipitation and Chromatin immunoprecipitation were used to validate the interactions.
Results
LAYN was highly expressed in the CHOL cells. Knockdown of LAYN significantly inhibited proliferation, migration, invasion, and EMT in both QBC-939 and RBE human CHOL cells, while overexpression of LAYN had the opposite effect. Furthermore, in a CHOL metastasis model using nude mice, knocking down LAYN expression markedly suppressed CHOL liver and lung metastases. LAYN interacts with TLN1, and CREB1 binds to the LAYN promoter, with all three showing a positive correlation. Additionally, bioinformatics analysis revealed high expression of both TLN1 and CREB1 in CHOL. Knockdown of TLN1 or CREB1 in QBC-939 and RBE cells inhibited cell proliferation, migration, invasion, and EMT, reversing the effects of LAYN overexpression. Moreover, knockdown of TLN1 or CREB1 also suppressed the expression of ITGB1 and the phosphorylation levels of c-Jun, p38 MAPK, and ERK, further reversing the effects of LAYN overexpression.