Isthmin-1 drives pancreatic cancer invasion and metastasis through epithelial-mesenchymal transition

To investigate the effect of isthmin-1 (ISM1) on the invasion and metastasis of pancreatic cancer and its underlying mechanism, this study analyzed the expression of ISM1 in pancreatic cancer patients and normal pancreatic tissues using The Cancer Genome Atlas (TCGA) database. Western blot was employed to detect differences in ISM1 protein expression between pancreatic cancer cell lines (Aspc1, Bxpc3, PANC1, SW1990) and the pancreatic epithelial cell line (hPNE). Cell models with stable ISM1 overexpression and knockdown were constructed, and changes in cell migration and invasion capabilities were assessed via Transwell invasion assays and wound healing assays. Meanwhile, Western blot was used to detect the expression levels of key markers of epithelial-mesenchymal transition (EMT). Furthermore, TCGA and the Gene Expression Omnibus (GEO) database were utilized to analyze pathways regulated downstream of ISM1 and the mechanisms promoting pancreatic cancer invasion and metastasis. Immunoprecipitation combined with mass spectrometry (IP-MS) was used to screen for vimentin as an ISM1-binding protein, and the interaction between ISM1 and vimentin was verified by immunofluorescence and co-immunoprecipitation (Co-IP). Bxpc3 cells overexpressing ISM1 were treated with the protein synthesis inhibitor cycloheximide (CHX) to detect vimentin protein stability. The results indicate that ISM1 promotes the EMT process by inhibiting vimentin degradation, thereby enhancing the invasion and metastasis of pancreatic cancer. This study provides new experimental evidence for elucidating the mechanism of pancreatic cancer metastasis.