LncRNA H19-Derived miR-675-3p Promotes Epithelial-Mesenchymal Transition and Stemness in Human Pancreatic Cancer Cells by targeting the STAT3 Pathway

Objective: The functional role and mechanism of the long noncoding RNA (lncRNA) H19 in regulating human pancreatic cancer (PC) cell stemness and invasion have not been completely elucidated. This study aimed to evaluate the role of H19 in regulating the stemness, epithelial-mesenchymal transition (EMT), invasion and chemosensitivity of PC cells. Methods: The sphere-forming ability was assessed using serum-free floating-culture systems. Chemosensitivity was evaluated via CCK-8 and flow cytometry assays in vitro. Migration and invasion were evaluated by transwell assays. The expression of stemness and EMT markers was detected by flow cytometry, qRT-PCR and western blot analyses. Xenograft initiation, growth and sensitivity were examined; Ki-67 nuclear staining intensity was evaluated by immunohistochemistry; and in situ apoptosis was evaluated by a TUNEL assay. Results: H19 played an important role in maintaining PC cell stemness. Upregulated H19 expression in CAPAN-1 cells promoted tumor cell migration, invasion, EMT and chemoresistance. In contrast, downregulated H19 expression in PANC-1 cells yielded the opposite results. These effects were mediated by positively modulating the STAT3 pathway. Furthermore, SOCS5, an endogenous inhibitor of the STAT3 pathway, was a direct target of miR-675-3p, which was positively regulated by H19 in PC cells. Conclusions: The H19/miR-675-3p signaling axis plays a critical role in maintaining the EMT process and stemness of PC cells by directly targeting SOCS5 to activate the STAT3 pathway. These data provide new insights into the oncogenic function of H19 in human PC and reveal potential targets for the development of optimal treatment approaches for this disease.