LncRNA ZNFTR functions as an inhibitor in pancreatic cancer by modulating ATF3/ZNF24/VEGFA pathway

The majority of long non-coding RNAs (lncRNAs) have been discovered to be overexpressed in pancreatic cancer (PC) and served as promoters in the tumorigenesis of PC, while the inhibitory functions of lncRNAs in the development of PC have not been fully elucidated yet. LncRNA microarray was adopted to analyze the differential expression of lncRNAs in PC tissues and that in normal peritumoral (NP) tissues. Functional role of lncRNA BM466146.1 on PC was evaluated by gain- and loss-of-function experiments in vivo and in vitro. RNA pull-down, RNA immunoprecipitation, luciferase reporter, and Chromatin-immunoprecipitation assays were performed to assess the mechanism of ZNFTR, respectively. The correlation between the expression of ZNFTR and various clinicopathological characteristics was accessed in PC specimens. This study displayed lncRNA BM466146.1 was downregulated in PC tissues and functioned as a suppressor through regulating the expression of adjacent gene Zinc finger protein 24 (ZNF24), which was assigned as ZNFTR. Mechanistically, ZNFTR interacted with activating transcription factor 3 (ATF3) and sequestered ATF3 away from the ZNF24 promoter, which consequently increased the expression of ZNF24. Further, ZNF24 inhibited the proliferative, metastatic, and pro-angiogenic abilities of PC cells by suppressing transcription of vascular endothelial growth factor A (VEGFA). Therefore, the downregulation of ZNFTR in PC led to the decreased expression of ZNF24, which further resulted in the upregulation of VEGFA to facilitate the development of PC. Meanwhile, ZNFTR was transcriptionally inhibited by the HIF-1α/HDAC1 complex-mediated deacetylation. Clinical results further demonstrated that the low expression of ZNFTR was associated with poor overall survival time. Taken together, our results implicated that ZNFTR was a hypoxia-responsive lncRNA, and functioned as an inhibitor by modulating ATF3/ZNF24/VEGFA pathway in PC.