Hu Wentao, Pei Weiwei, Zhu Lin, Nie Jing, Pei Hailong, Zhang Jian, Li Bingyan, Hei Tom K, Zhou Guangming
School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, China.
Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou, China.
Cell Physiol Biochem. 2018;50(6):2071-2085. doi: 10.1159/000495052. Epub 2018 Nov 13.
BACKGROUND/AIMS: TGF-β1 mediated radiation-induced bystander effects (RIBE) have been linked with malignant transformation and tumorigenesis. However, the underlying mechanisms are not fully understood.
To reveal new molecules of regulatory functions in this process, lncRNA microarray was performed to profile both lncRNA and mRNA expression patterns in human lung bronchial epithelial BEAS-2B cells treated with TGF-β1 at a concentration measured in the medium conditioned by directly irradiated BEAS-2B cells. The potential functions of the differentially expressed lncRNAs were predicted by GO and KEGG pathway analyses of their co-expressed mRNAs. Cis- and trans-regulation of the lncRNAs were analyzed and the interaction networks were constructed using Cytoscape. qRT-PCR was conducted to validate the results of microarray profiling. CCK-8 assay was employed for functional validation of 3 identified lncRNAs.
224 lncRNAs were found to be dysregulated, among which 6 lncRNAs were chosen for expression validation by qRT-PCR assay. Pathway analyses showed that differentially expressed lncRNAs are highly correlated with cell proliferation, transformation, migration, etc. Trans-regulation analyses showed that the differentially expressed lncRNAs most likely participate in the pathways regulated by four transcriptional factors, FOS, STAT3, RAD21 and E2F1, which have been identified to be involved in the modulation of oncogenic transformation, cell cycle progression, genomic instability, etc. lnc-THEMIS-2 and lnc-ITGB6-4, predicted to be regulated by STAT3 and E2F1 respectively, were found to rescue the decrease of cell viability induced by TGF-β1 treatment.
Our findings suggest that the differentially expressed lncRNAs induced by TGF-β1 play crucial roles in the oncogenic transformation and tumorigenesis, which provide a better understanding of the underlying mechanisms related to tumorigensis induced by LD/LDR radiations.
背景/目的：转化生长因子-β1（TGF-β1）介导的辐射旁效应（RIBE）与恶性转化和肿瘤发生有关。然而，其潜在机制尚未完全明确。
为揭示此过程中具有调节功能的新分子，利用长链非编码RNA（lncRNA）芯片分析了经直接照射的人肺支气管上皮BEAS-2B细胞条件培养基中所测浓度的TGF-β1处理后的BEAS-2B细胞中lncRNA和mRNA的表达模式。通过对差异表达lncRNA共表达mRNA的基因本体（GO）和京都基因与基因组百科全书（KEGG）通路分析预测差异表达lncRNA的潜在功能。分析lncRNA的顺式和反式调控，并使用Cytoscape构建相互作用网络。采用实时定量聚合酶链反应（qRT-PCR）验证芯片分析结果。采用细胞计数试剂盒-8（CCK-8）法对3个鉴定出的lncRNA进行功能验证。
发现224个lncRNA表达失调，其中6个lncRNA通过qRT-PCR法进行表达验证。通路分析表明，差异表达的lncRNA与细胞增殖、转化、迁移等高度相关。反式调控分析表明，差异表达的lncRNA最有可能参与由四个转录因子FOS、信号转导和转录激活因子3（STAT3）、RAD21和E2F1调控的通路，这些转录因子已被确定参与致癌转化、细胞周期进程、基因组不稳定等的调节。预测分别受STAT3和E2F1调控的lnc-THEMIS-2和lnc-ITGB6-4被发现可挽救TGF-β1处理诱导的细胞活力下降。
我们的研究结果表明，TGF-β1诱导的差异表达lncRNA在致癌转化和肿瘤发生中起关键作用，这有助于更好地理解低剂量/低剂量率辐射诱导肿瘤发生的潜在机制。
