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BACKGROUND: Some studies have shown that CD133 is a stem cell marker for a variety of tumor cells, such as pancreatic cancer, which is associated with a poor prognosis in cancer patients. miR-15 family is involved in cell apoptosis, differentiation, cycle regulation and stress, and has potential value as an intervention. OBJECTIVE: To investigate the effects of miR-15 family on the migration and invasion of CD133+ pancreatic cancer stem-like cells. METHODS: First, a highly migrating pancreatic cancer cell line, Capan-1M9, was constructed, and then CD133+Capan-1M9 cell lines that overexpressed miR-15a, miR-15b and miR-15c were constructed by lentivirus transduction. NC-miRNA cell lines were taken as negative controls. Expression of miR-15a, miR-15b and miR-15c in the recombinant cell lines and epithelial-mesenchymal transition (EMT)-related proteins, fibronectin, vimentin and N-cadherin mRNA were determined by qRT-PCR. MTT assay was used to detect the proliferation and gemcitabine resistance of recombinant cell lines. Spheroid formation test was used to detect the self-renewal ability of recombinant cell lines. Migration and invasion ability of the recombinant cell lines were detected by cell migration and invasion assay. EMT-related proteins fibronectin, vimentin and N-cadherin were detected by western blot. RESULTS AND CONCLUSION: qPCR results showed that the expression of miR-15a, miR-15b and miR-15c in the CD133+ Capan-1M9 cell lines increased by 8.3, 10 and 9.5 times compared with the negative control group, and the expression of fibronectin, vimentin and N-cadherin mRNA was also significantly increased (P < 0.05). There was no significant difference in cell proliferation between the recombinant cell lines and the negative control group (P > 0.05), but the gemcitabine resistance was significantly increased in the recombinant cell lines as detected by the MTT (P < 0.05). The number and volume of spheres in the recombinant cell lines did not change significantly compared with the negative control group (P > 0.05). The cell migration and invasion abilities of the recombinant cell line were significantly enhanced compared with the negative control group (P < 0.05). Our experimental findings suggest that the miR-15 family can promote migration and invasion of CD133+ pancreatic cancer stem-like cells via EMT regulation. [ABSTRACT FROM AUTHOR]