MYBL2 诱导的 PITPNA-AS1 通过 miR-520d-5p 和 DDX54 上调 SIK2，从而在三阴性乳腺癌中发挥致癌作用。

MYBL2-induced PITPNA-AS1 upregulates SIK2 to exert oncogenic function in triple-negative breast cancer through miR-520d-5p and DDX54.

机构信息

Department of Andrology, The First Affiliated Hospital of University of South China, Hengyang, 421001, Hunan, China.

Changsha Social Work College, Changsha, 421004, Hunan, China.

出版信息

J Transl Med. 2021 Aug 5;19(1):333. doi: 10.1186/s12967-021-02956-6.

BACKGROUND

In recent years, long non-coding RNAs (lncRNAs) have attracted much attention because of its regulatory role in occurrence and progression of tumors, including triple-negative breast cancer (TNBC). LncRNA PITPNA antisense RNA 1 (PITPNA-AS1) has been explored in some cancers, whereas its function and molecular mechanism in TNBC remain unclear.

METHODS

PITPNA-AS1 expression in TNBC tissues and cells was determined by RT-qPCR. TNBC cell viability, proliferation, migration, invasion were assessed with CCK-8, colony formation, wound healing, transwell assays. Cell apoptosis was evaluated by flow cytometry. Expression of EMT-related markers was detected by western blot analyses. The molecular mechanism of PITPNA-AS1 was explored by RNA pull down, luciferase reporter, RIP and ChIP assays.

RESULTS

PITPNA-AS1 showed high expression levels in TNBC tissues and cells. PITPNA-AS1 knockdown suppressed TNBC cell viability, proliferation, migration, invasion in vitro and inhibited xenograft tumor growth in mice. Mechanistically, PITPNA-AS1 upregulated SIK2 expression by sponging miR-520d-5p and recruiting DDX54 protein. Results of rescue assays suggested that the inhibitive effects of silenced PITPNA-AS1 on TNBC cellular processes were partially rescued by overexpressing SIK2 or combination of miR-520d-5p inhibition and DDX54 overexpression. More importantly, we found that the upregulation of PITPNA-AS1 in TNBC cells was attributed to transcription factor MYBL2.

CONCLUSION

PITPNA-AS1 activated by MYBL2 plays an oncogenic role in TNBC through upregulating SIK2.

背景

近年来，长非编码 RNA（lncRNA）因其在肿瘤发生和发展中的调节作用而受到关注，包括三阴性乳腺癌（TNBC）。lncRNA PITPNA 反义 RNA 1（PITPNA-AS1）在一些癌症中得到了探索，但其在 TNBC 中的功能和分子机制尚不清楚。

方法

采用 RT-qPCR 检测 TNBC 组织和细胞中 PITPNA-AS1 的表达。采用 CCK-8、集落形成、划痕愈合、Transwell 检测评估 TNBC 细胞活力、增殖、迁移和侵袭。采用流式细胞术评估细胞凋亡。采用 Western blot 分析检测 EMT 相关标志物的表达。通过 RNA 下拉、荧光素酶报告、RIP 和 ChIP 检测探索 PITPNA-AS1 的分子机制。

结果

PITPNA-AS1 在 TNBC 组织和细胞中呈高表达。PITPNA-AS1 敲低抑制 TNBC 细胞体外活力、增殖、迁移和侵袭，并抑制小鼠异种移植肿瘤生长。机制上，PITPNA-AS1 通过海绵吸附 miR-520d-5p 和募集 DDX54 蛋白而上调 SIK2 的表达。挽救实验结果表明，沉默 PITPNA-AS1 对 TNBC 细胞过程的抑制作用部分被 SIK2 过表达或 miR-520d-5p 抑制和 DDX54 过表达的组合所挽救。更重要的是，我们发现 TNBC 细胞中 PITPNA-AS1 的上调归因于转录因子 MYBL2。