Molecular Characterization of the miRNA with the Response to the Small Molecule Atranorin in Triple-Negative Breast Cancer

Triple negative breast cancer (TNBC) is a highly aggressive breast cancer subtype with limited therapeutic targets. Atranorin, a bioactive small molecule from lichens, has shown anticancer potential, but its molecular role in TNBC remains unclear. The present study aimed to identify and construct lncRNA associated competing endogenous RNA (ceRNA) networks involved in the response of TNBC to atranorin, thereby elucidating the underlying regulatory mechanisms of atranorin and identifying potential therapeutic targets for TNBC. In this study, the cytotoxic effect of atranorin on TNBC cell lines representing different molecular subtypes (MDAMB231, MDAMB468, BT20) was investigated. Differentially expressed long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and mRNAs in response to atranorin were identified treatment using several NGS technologies. Bioinformatics analyses facilitated the construction of a ceRNA network comprising 10 lncRNAs, 29 miRNAs, and 145 mRNAs, highlighting key regulatory axes associated with the mechanisms of action of atranorin in TNBC. Functional enrichment analysis, including GO and KEGG, was performed to elucidate the underlying mechanisms and pathways involved in the TNBC response to atranorin treatment. Atranorin revealed significant inhibition of cell viability with minimal toxicity in normal breast epithelial cells (MCF10A). The analysis revealed significant enrichment of mRNAs within the ceRNA network in AKT mTOR and Wnt signaling, cell proliferation, epithelial development, key molecular interactions such as Wnt-protein and beta-catenin binding, and complexes including WntFrizzledLRP56 and PI3K. These findings provide novel understandings into the molecular characterization of mechanism of atranorin in TNBC and highlight possible prognostic and predictive biomarkers and therapeutic targets for this challenging breast cancer subtype.

三阴性乳腺癌（Triple negative breast cancer, TNBC）是一类侵袭性极强的乳腺癌亚型，治疗靶点极为有限。扁枝衣酸（atranorin）作为来源于地衣的生物活性小分子，已展现出抗癌潜力，但其在TNBC中的分子调控机制仍未明确。本研究旨在鉴定并构建参与TNBC应答扁枝衣酸的长链非编码RNA（long non-coding RNAs, lncRNAs）相关竞争性内源RNA（competing endogenous RNA, ceRNA）调控网络，以此阐明扁枝衣酸发挥作用的潜在调控机制，并筛选TNBC潜在治疗靶点。本研究首先考察了扁枝衣酸对三种不同分子亚型的TNBC细胞系（MDAMB231、MDAMB468、BT20）的细胞毒性效应。通过多种下一代测序（next-generation sequencing, NGS）技术，鉴定了扁枝衣酸处理后差异表达的长链非编码RNA、微小RNA（microRNAs, miRNAs）及信使RNA（messenger RNA, mRNAs）。借助生物信息学分析，成功构建了包含10个长链非编码RNA、29个微小RNA与145个信使RNA组成的ceRNA网络，明确了与扁枝衣酸调控TNBC的关键调控轴。本研究开展了包括基因本体论（Gene Ontology, GO）与京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）在内的功能富集分析，以解析TNBC应答扁枝衣酸治疗的潜在分子机制与通路。实验结果显示，扁枝衣酸可显著抑制TNBC细胞活力，且对正常乳腺上皮细胞（MCF10A）的毒性极低。分析结果表明，ceRNA网络中的靶信使RNA显著富集于AKT-mTOR、Wnt信号通路，细胞增殖、上皮发育等生物学过程，Wnt蛋白与β-连环蛋白（beta-catenin）结合等关键分子互作，以及Wnt-Frizzled-LRP5/6复合物、磷脂酰肌醇3-激酶（phosphatidylinositol 3-kinase, PI3K）相关复合物等。本研究结果为阐明扁枝衣酸在TNBC中的作用机制提供了全新的分子认知，并为这类难治性乳腺癌亚型的预后预测生物标志物及治疗靶点提供了潜在候选。