LncRNA NORAD Regulates the Effect of miR-363-3p/BTG2 on the Proliferation and Migration of Prostate Cancer Cells
HU Xun, HU Chuanqing*
This study investigated the role of lncRNA (long non-coding RNA) NORAD in regulating the miR-363-3p/BTG2 (B-cell translocation gene 2) axis and its impact on proliferation, migration, and EMT (epithelial-mesenchymal transition) in PC (prostate cancer) cells. Tumor tissues and adjacent non-tumor tissues were collected from PC patients who underwent surgical resection at the Second Hospital of Huangshi between August 2023 and July 2024. The expression levels of lncRNA NORAD, miR-363-3p, and BTG2 in PC tissues and cells were measured by qRT-PCR (quantitative real-time PCR). Pearson correlation analysis was used to assess the relationships among gene expressions. LNCaP PC cells were divided into the following groups: Blank, sh-NC, sh-NORAD, sh-NORAD+inhibitor-NC, and sh-NORAD+miR-363-3p inhibitor. Cell proliferation was evaluated using MTT and colony formation assays; cell migration was assessed via wound healing and Transwell assays; Western blot was performed to detect the protein levels of BTG2 and EMT markers; and dual-luciferase reporter assays were conducted to verify the targeting relationships between NORAD and miR-363-3p, as well as between miR-363-3p and BTG2. The results showed that the mRNA expression levels of lncRNA NORAD and BTG2 were significantly higher in PC tissues than in adjacent normal tissues (P<0.05), whereas miR-363-3p expression was significantly lower (P<0.05). In acinar adenocarcinoma tissues, lncRNA NORAD expression was negatively correlated with miR-363- 3p (r=–0.765, P<0.05); miR-363-3p expression was negatively correlated with BTG2 (r=–0.518, P<0.05); and lncRNA NORAD expression was positively correlated with BTG2 (r=0.649, P<0.05). Histopathological examination revealed that compared with adjacent normal tissues, PC tissues exhibited disrupted acinar architecture, disordered cellular arrangement, abnormal cell morphology, enlarged and hyperchromatic nuclei with irregular shapes, tumor cell infiltration into the stroma, and accompanying fibrous tissue proliferation. Compared with the sh-NC group, the sh-NORAD group showed significant downregulation of lncRNA NORAD, BTG2 mRNA, and proteins (BTG2, N-cadherin, and Vimentin). Concurrently, miR-363-3p expression and E-cadherin protein levels were upregulated. Functionally, cell viability, colony formation, wound healing, and cell migration were all significantly impaired (all P<0.05). In contrast, the sh-NORAD+miR-363-3p inhibitor group showed significantly higher cell viability, colony numbers, wound healing rates, numbers of migrated cells, BTG2 mRNA levels, and protein expression of BTG2, Ncadherin, and Vimentin compared with the sh-NORAD+inhibitor-NC group; conversely, lncRNA NORAD, miR363-3p expression and E-cadherin protein levels were significantly lower (all P<0.05). Furthermore, co-transfection of either NORAD-WT or BTG2-WT with miR-363-3p mimics resulted in significantly lower relative luciferase activity compared to co-transfection with miR-NC (P<0.05). In conclusion, miR-363-3p directly targets and suppresses BTG2 expression, while lncRNA NORAD acts as a ceRNA (competing endogenous RNA) by sponging miR-363-3p, thereby promoting PC cell proliferation, migration, and EMT.
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