Hu Ying, Sun Zihan, Deng Jinmu, Hu Baoquan, Yan Wenting, Wei Hongyi, Jiang Jun
1 Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing, China.
2 Department of Mammary Gland and Thyroid Gland, Chongqing Hospital of Traditional Chinese Medicine, Chongqing, China.
Tumour Biol. 2017 Mar;39(3):1010428317694318. doi: 10.1177/1010428317694318.
Increasing evidence has indicated that the splicing factor hnRNPA2B1 plays a direct role in cancer development, progression, gene expression, and signal transduction. Previous studies have shown that knocking down hnRNPA2B1 in breast cancer cells induces apoptosis, but the mechanism and other functions of hnRNPA2B1 in breast cancer are unknown. The goal of this study was to investigate the biological function, clinical significance, and mechanism of hnRNPA2B1 in breast cancer. The expression of hnRNPA2B1 in 92 breast cancer and adjacent normal tissue pairs was analyzed by immunohistochemical staining. Stable clones exhibiting knockdown of hnRNPA2B1 via small hairpin RNA expression were generated using RNA interference technology in breast cancer cell lines. The effects of hnRNPA2B1 on cell proliferation were examined by MTT and EdU assay, and cellular apoptosis and the cell cycle were examined by flow cytometry. A nude mouse xenograft model was established to elucidate the function of hnRNPA2B1 in tumorigenesis in vivo. The role of hnRNPA2B1 in signaling pathways was investigated in vitro. Our data revealed that hnRNPA2B1 was overexpressed in breast cancer tissue specimens and cell lines. Knockdown of hnRNPA2B1 reduced breast cancer cell proliferation, induced apoptosis, and prolonged the S phase of the cell cycle in vitro. In addition, hnRNPA2B1 knockdown suppressed subcutaneous tumorigenicity in vivo. On a molecular level, hnRNPA2B1 knockdown decreased signal transducer and activator of transcription 3 and extracellular-signal-regulated kinase 1/2 phosphorylation. We concluded that hnRNPA2B1 promotes the tumorigenic potential of breast cancer cells, MCF-7 and MDA-MB-231, through the extracellular-signal-regulated kinase 1/2 or signal transducer and activator of transcription 3 pathway, which may serve as a target for future therapies.
越来越多的证据表明，剪接因子hnRNPA2B1在癌症的发生、发展、基因表达和信号转导中起直接作用。先前的研究表明，敲低乳腺癌细胞中的hnRNPA2B1可诱导细胞凋亡，但hnRNPA2B1在乳腺癌中的作用机制和其他功能尚不清楚。本研究的目的是探讨hnRNPA2B1在乳腺癌中的生物学功能、临床意义及机制。通过免疫组织化学染色分析了92对乳腺癌及癌旁正常组织中hnRNPA2B1的表达。利用RNA干扰技术在乳腺癌细胞系中构建了通过小发夹RNA表达敲低hnRNPA2B1的稳定克隆。通过MTT和EdU试验检测hnRNPA2B1对细胞增殖的影响，通过流式细胞术检测细胞凋亡和细胞周期。建立裸鼠异种移植模型以阐明hnRNPA2B1在体内肿瘤发生中的作用。在体外研究了hnRNPA2B1在信号通路中的作用。我们的数据显示，hnRNPA2B1在乳腺癌组织标本和细胞系中过表达。敲低hnRNPA2B1可降低乳腺癌细胞增殖、诱导细胞凋亡并延长体外细胞周期的S期。此外，敲低hnRNPA2B1可抑制体内皮下肿瘤形成。在分子水平上，敲低hnRNPA2B1可降低信号转导和转录激活因子3以及细胞外信号调节激酶1/2的磷酸化水平。我们得出结论，hnRNPA2B1通过细胞外信号调节激酶1/2或信号转导和转录激活因子3途径促进MCF-7和MDA-MB-231乳腺癌细胞的致瘤潜能，这可能成为未来治疗的靶点。
