Department of Stomatology, The Fourth Hospital of Hebei Medical University, Hebei Medical University, Shijiazhuang, China.
Neoplasma. 2020 May;67(3):461-472. doi: 10.4149/neo_2020_190430N382. Epub 2020 Feb 28.
Oral cancer is one of the common cancers worldwide, among which over 90% are oral squamous cell carcinomas (OSCC). MicroRNAs act as critical regulators of cancer development and progression. MiR-103a-3p has been reported to be upregulated in OSCC patients and closely correlated to poor prognosis, yet its roles in the progression of OSCC remain undisclosed. In this study, we knocked down the expression of miR-103a-3p in two OSCC cell lines in vitro, and significantly repressed cell proliferation and cell cycle arrest at the G1 phase were observed, accompanied by decreased proliferating cell nuclear antigen, cyclin D1, cyclin B1 and increased PTEN levels. MiR-103a-3p inhibition also induced apoptosis as evidenced by increased apoptotic cells and upregulated cleaved caspase-9/casapase-3 expression. We established a xenograft model in nude mice and found that miR-103a-3p knockdown also suppressed tumor growth in vivo. Besides, the expression of regulator of calcineurin1 (RCAN1), known as its anti-tumor effect, was negatively correlated with the miR-103a-3p level in OSCC cells. We validated that RCAN1 was a downstream target of miR-103a-3p using the dual-luciferase assay. RCAN1 silencing reversed the cell proliferative inhibition, cell cycle arrest and cell apoptosis induced by miR-103a-3p knockdown. In addition, we found that long non-coding RNA LINC00675 acted as a sponge of miR-103a-3p and promoted the expression of miR-103a-3p targets RCAN1 and PTEN. In summary, miR-103a-3p inhibition represses proliferation and induces apoptosis of OSCC cells through regulating RCAN1, and miR-103a-3p may act as a novel diagnostic marker and therapeutic target for OSCC.
口腔癌是全球常见的癌症之一，其中超过 90%为口腔鳞状细胞癌（OSCC）。microRNA 作为癌症发生和发展的关键调节因子。有报道称，miR-103a-3p 在 OSCC 患者中上调，并与不良预后密切相关，但它在 OSCC 进展中的作用仍不清楚。在本研究中，我们在体外敲低了两种 OSCC 细胞系中 miR-103a-3p 的表达，观察到细胞增殖显著受到抑制，细胞周期阻滞在 G1 期，同时增殖细胞核抗原、cyclin D1、cyclin B1 减少，PTEN 水平升高。miR-103a-3p 抑制也诱导了细胞凋亡，表现为凋亡细胞增多和 cleaved caspase-9/caspase-3 表达上调。我们在裸鼠中建立了异种移植模型，发现 miR-103a-3p 敲低也抑制了体内肿瘤生长。此外，已知具有抗肿瘤作用的钙调神经磷酸酶 1 调节剂（RCAN1）的表达与 OSCC 细胞中的 miR-103a-3p 水平呈负相关。我们通过双荧光素酶报告基因实验验证了 RCAN1 是 miR-103a-3p 的下游靶基因。RCAN1 沉默逆转了 miR-103a-3p 敲低引起的细胞增殖抑制、细胞周期阻滞和细胞凋亡。此外，我们发现长链非编码 RNA LINC00675 作为 miR-103a-3p 的海绵，促进了 miR-103a-3p 靶基因 RCAN1 和 PTEN 的表达。总之，miR-103a-3p 抑制通过调节 RCAN1 抑制 OSCC 细胞的增殖并诱导其凋亡，miR-103a-3p 可能作为 OSCC 的新型诊断标志物和治疗靶点。
