Lin Jianqing, Chen Zhiyao, Wu Shanhu, Huang Wenbo, Chen Feng, Huang Zhijun
Department of Surgical Oncology, the Second Affiliated Hospital of Fujian Medical University, Quanzhou 362000, Fujian, China.
Jianqing Lin and Zhiyao Chen are co-first authors.
J Cancer. 2019 Aug 28;10(21):5139-5152. doi: 10.7150/jca.30816. eCollection 2019.
In our previous study we have found that miR-548k has oncogenic roles in esophageal squamous cell carcinoma (ESCC) via repressing long noncoding RNA (lncRNA)-LET and further upregulating nuclear factor 90 (NF90). However, the upstream factors controlling miR-548k expression are still unknown. In this study, we found NF90 directly binds pri-miR-548k, increases the stability of pri-miR-548k, and upregulates the expression of pri-miR-548k and miR-548k. Therefore, NF90, miR-548k and lncRNA-LET forms a feedback loop. Gain-of-function and loss-of-function assays demonstrated that in accordance with the roles of miR-548k, NF90 also promotes ESCC cell proliferation and migration. Furthermore, we verified the regulatory feedback loop between NF90, miR-548k, and lncRNA-LET. We found NF90 upregulated miR-548k and downregulated lncRNA-LET. miR-548k downregulated lncRNA-LET and upregulated NF90. lncRNA-LET downregulated NF90 and miR-548k. Through the reciprocal regulations between each other, the NF90/miR-548k/lncRNA-LET feedback loop controls the expressions of NF90 targets (HIF-1α and VEGF), miR-548k targets (KLF10 and EGFR), and lncRNA-LET target (p53). Further functional assays demonstrated that activation of the NF90/miR-548k/lncRNA-LET feedback loop via simultaneously overexpressing NF90 and miR-548k and simultaneously depleting lncRNA-LET significantly promotes ESCC cell proliferation and migration and ESCC tumor growth . Targeting the NF90/miR-548k/lncRNA-LET feedback loop via simultaneously depleting NF90 and miR-548k and simultaneously overexpressing lncRNA-LET significantly inhibits ESCC cell proliferation and migration and ESCC tumor growth . In summary, our findings identified a crucial oncogenic NF90/lncRNA-LET/miR-548k feedback amplification loop, which may be promising therapeutic targets for ESCC.
在我们之前的研究中，我们发现miR-548k通过抑制长链非编码RNA（lncRNA）-LET并进一步上调核因子90（NF90），在食管鳞状细胞癌（ESCC）中发挥致癌作用。然而，控制miR-548k表达的上游因子仍然未知。在本研究中，我们发现NF90直接结合初级miR-548k，增加初级miR-548k的稳定性，并上调初级miR-548k和miR-548k的表达。因此，NF90、miR-548k和lncRNA-LET形成了一个反馈环。功能获得和功能丧失实验表明，与miR-548k的作用一致，NF90也促进ESCC细胞的增殖和迁移。此外，我们验证了NF90、miR-548k和lncRNA-LET之间的调控反馈环。我们发现NF90上调miR-548k并下调lncRNA-LET。miR-548k下调lncRNA-LET并上调NF90。lncRNA-LET下调NF90和miR-548k。通过彼此之间的相互调控，NF90/miR-548k/lncRNA-LET反馈环控制NF90靶标（HIF-1α和VEGF）、miR-548k靶标（KLF10和EGFR）以及lncRNA-LET靶标（p53）的表达。进一步的功能实验表明，通过同时过表达NF90和miR-548k以及同时消耗lncRNA-LET来激活NF90/miR-548k/lncRNA-LET反馈环，可显著促进ESCC细胞的增殖和迁移以及ESCC肿瘤生长。通过同时消耗NF90和miR-548k以及同时过表达lncRNA-LET来靶向NF90/miR-548k/lncRNA-LET反馈环，可显著抑制ESCC细胞的增殖和迁移以及ESCC肿瘤生长。总之，我们的研究结果确定了一个关键的致癌NF90/lncRNA-LET/miR-548k反馈放大环，这可能是ESCC有前景的治疗靶点。
