DHRS4-AS1 Regulate Gastric Cancer Apoptosis and Cell Proliferation by Destabilizing DHX9 and Inhibited the Association Between DHX9 and ILF3

Gastric cancer (GC) causes millions of cancer-related deaths due to anti-apoptosis and rapid proliferation. However, the molecular mechanisms underlying GC cell proliferation and anti-apoptosis remain unclear. The expression levels of DHRS4-AS1 in GC were analyzed based on GEO database and recruited GC patients in our institution. We found that DHRS4-AS1 was significantly downregulated in GC. The expression of DHRS4-AS1 in GC tissues showed a significant correlation with tumor size, advanced pathological stage, and vascular invasion. Moreover, DHRS4-AS1 levels in GC tissues were significantly associated with prognosis. DHRS4-AS1 markedly inhibited GC cell proliferation and promotes apoptosis in vitro and in vivo assays. Mechanically, We found that DHRS4-AS1 bound to pro-oncogenic DHX9 (DExH-box helicase 9) and recruit the E3 ligase MDM2 that contributed to DHX9 degradation. We also confirmed that DHRS4-AS1 inhibited DHX9-mediated cell proliferation and promotes apoptosis. Furthermore, we found DHX9 interact with ILF3 (Interleukin enhancer Binding Factor 3) and activate NF-kB Signaling in a ILF3-dependent Manner. Moreover, DHRS4-AS1 can also inhibit the association between DHX9 and ILF3 thereby interfered the activation of the signaling pathway. Our results reveal new insights into mechanisms underlying GC progression and indicate that LncRNA DHRS4-AS1 could be a future therapeutic target and a biomarker for GC diagnosis.