Introduction: Pancreatic Ductal Adenocarcinoma (PDAC) stem cells (CSCs) play a vital role in the occurrence, development and recurrence of PDAC. Previous studies have shown that long non-coding RNAs (lncRNA) are closely associated with occurrence and development of malignant tumors. Among them, a LncRNA called homeobox transcription antisense RNA (HOTAIR) plays a key role in cancer progression in a variety of malignant tumors, including PDAC. Numerous studies have associated HOTAIR with poor prognosis of malignant tumor treatment, owing to its role in regulating downstream microRNAs (miRNAs). However, its underlying mechanism of action on CSCs-like properties of PDAC remain unclear.
Methods: We enriched CSCs of PDAC with a serum-free medium (SFM), and analyzed the expression levels of HOTAIR and miR-34a after enrichment. In addition, we evaluated the regulatory effects of HOTAIR and miR-34a on CSCs-like properties, invasion and migration of PDAC. Finally, we elucidated the role of HOTAIR in pancreatic tumor xenotransplantation.
Results: HOTAIR was upregulated in CSCs following PDAC enrichment of PDAC. Conversely, miR-34a was downregulated and appeared to be a direct target of HOTAIR. Moreover, knocking down HOTAIR or overexpressing miR-34a significantly inhibited CSCs-like properties, invasion and migration of PDAC cells. Furthermore, HOTAIR activated the JAK2/STAT3 pathway through miR-34a, thereby promoting CSCs-like properties, invasion and migration of PDAC cells. In vivo experiments indicated that knocking down HOTAIR could inhibit the tumorigenicity of CFPAC-1 cells.
Conclusion: This is the first report of HOTAIR-mediated activation of the JAK2/STAT3 pathway via miR-34a inhibition. This activation promotes CSCs-like properties, invasion and migration of PDAC.
Keywords: pancreatic ductal adenocarcinoma, lncRNA HOTAIR, miR-34a, CSCs-like properties, JAK2/STAT3 pathway