Lung adenocarcinoma (LUAD), a common type of lung cancer, has become a popularly aggressive cancer. Long noncoding RNAs (lncRNAs) play a critical role in the pathogenesis of human cancers, while the function of double homeobox A pseudogene 8 (DUXAP8) in LUAD remains to be fully inquired. Therefore, our study was conducted to elucidate the DUXAP8 expression in LUAD and its mechanism on the biological features of LUAD cells. Loss-of-function experiments were performed to assess the function of DUXAP8 proliferation and apoptosis of H1975 and A549 cells. Functionally, silencing DUXAP8 inhibited proliferation and induced apoptosis of LUAD cells. Mechanistically, further correlation assay indicated a negative association between miR-26b-5p and DUXAP8 expression. Subsequently, we testified that DUXAP8 exerted its role in the progression and development of LUAD through targeting miR-26b-5p. In summary, our results elucidated that that DUXAP8 promoted tumor progression in LUAD by targeting miR-26b-5p, which provide a novel therapeutic target for diagnosis and therapy of LUAD.

PurposeRecent studies have shown that STIP1 is associated with proliferation and migration in numerous types of tumors; however, the role of STIP1 in lung adenocarcinoma is still poorly understood. Therefore, the aim of this study was to evaluate the role of STIP1 in lung adenocarcinoma, in vitro and in vivo.MethodsThe expression of STIP1 in lung adenocarcinoma was assessed by immunohistochemistry, RT-qPCR, and Western blot. The effects of STIP1 on the proliferation of lung adenocarcinoma cells were detected by the cell counting kit-8 assay; the effect of STIP1 on adhesion of lung adenocarcinoma cells was detected by Giemsa staining, while the cell scratch and Transwell assays were employed to examine the effect of STIP1 on the migratory ability of lung adenocarcinoma cells. Finally, apoptosis was evaluated by Hoechst staining and flow cytometry.ResultsThe expression level of STIP1 in lung adenocarcinoma tissue was significantly higher than that in adjacent normal tissue (P<0.05). Compared with that in nontransfected controls, cell proliferation, adhesion, and migration, as well as vimentin protein expression and levels of phosphorylated JAK2/STAT3, were significantly decreased (P<0.05) in A549 lung adenocarcinoma cells transfected with STIP1 shRNA, whereas E-cadherin protein expression and rates of apoptosis were significantly increased in these cells (P< 0.05).ConclusionElevated expression of STIP1 in lung adenocarcinoma may enhance the proliferative, adhesive, and migratory ability, and reduce the apoptosis of lung adenocarcinoma cells through the JAK2/STAT3 signaling pathway and epithelial-mesenchymal transition (EMT), thereby promoting the recurrence and metastatic potential of this cancer. The results indicate that STIP1 may be an effective therapeutic target for the treatment of lung adenocarcinoma.