Department of Biochemistry and Molecular Biology, Central University of Kerala, Kasaragod, Kerala, 671316, India.
Mol Biol Rep. 2023 Apr;50(4):3413-3428. doi: 10.1007/s11033-023-08308-5. Epub 2023 Feb 8.
Y-box binding protein 1 (YBX1) is a multifunctional oncoprotein that can interact with several long non-coding RNAs (lncRNAs) to regulate metastasis in malignancies including breast cancer (BC). In the present study, we demonstrated the association of YBX1 with oncogenic lncRNA SBF2-AS1 (SET-binding factor 2 antisense RNA 1) via PI3K/AKT/mTOR signaling to regulate BC cell proliferation. We further explored the involvement of the YBX1/SBF2-AS1/PI3K/AKT/mTOR axis in the restoration of tamoxifen (TAM) sensitivity.
YBX1-SBF2-AS1 association was predicted in silico and verified by RNA immunoprecipitation (RIP)-qPCR assay. Transfection experiments, Real-time RT PCR, Western blots, Phospho AKT/mTOR antibody array kit, and cell proliferation/apoptosis assays were employed to detect the YBX1/SBF2-AS1/ PI3K/AKT/mTOR axis and its effects upon TAM treatment in vitro. We identified that the YBX1 protein specifically binds to lncRNA SBF2-AS1. Our transfection experiments in MCF-7 and MDA-MB-468 cells with SBF2-AS1 silenced or overexpressed YBX1 plasmids, and their negative controls revealed that YBX1 regulates the expression of SBF2-AS1 by forming a positive feedback loop for its activation. We further demonstrated YBX1-SBF2-AS1 association exerts its effects on cell proliferation via PI3K/AKT/mTOR signaling pathway. Furthermore, we observed an increase in TAM sensitivity in BC cells after the knockdown of YBX1-SBF2-AS1 marked by decreased cell proliferation through disruption of the PI3K/AKT/mTOR axis.
Our study has identified a novel YBX1/SBF2-AS1/PI3K/AKT/mTOR regulatory axis which may serve as a potential target to improve the effectiveness and efficacy of TAM treatment in BC.
Y 盒结合蛋白 1（YBX1）是一种多功能癌蛋白，可与几种长链非编码 RNA（lncRNA）相互作用，调节包括乳腺癌（BC）在内的恶性肿瘤的转移。在本研究中，我们通过 PI3K/AKT/mTOR 信号证实 YBX1 与致癌 lncRNA SBF2-AS1（SET 结合因子 2 反义 RNA 1）相关，以调节 BC 细胞增殖。我们进一步探讨了 YBX1/SBF2-AS1/PI3K/AKT/mTOR 轴在恢复他莫昔芬（TAM）敏感性中的作用。
通过 RNA 免疫沉淀（RIP）-qPCR 实验预测 YBX1-SBF2-AS1 关联，并进行验证。通过转染实验、实时 RT-PCR、Western blot、磷酸化 AKT/mTOR 抗体阵列试剂盒和细胞增殖/凋亡实验检测 YBX1/SBF2-AS1/PI3K/AKT/mTOR 轴及其对 TAM 治疗的体外影响。我们发现 YBX1 蛋白特异性结合 lncRNA SBF2-AS1。我们在 MCF-7 和 MDA-MB-468 细胞中进行的转染实验中，沉默或过表达 SBF2-AS1 的 YBX1 质粒及其阴性对照，结果表明 YBX1 通过形成 SBF2-AS1 的正反馈回路来调节其表达。我们进一步证明，YBX1-SBF2-AS1 关联通过 PI3K/AKT/mTOR 信号通路对细胞增殖产生影响。此外，我们观察到 YBX1-SBF2-AS1 敲低后，BC 细胞对 TAM 的敏感性增加，这是通过破坏 PI3K/AKT/mTOR 轴导致细胞增殖减少而实现的。
本研究确定了一种新的 YBX1/SBF2-AS1/PI3K/AKT/mTOR 调节轴，可能成为提高 TAM 治疗 BC 有效性和疗效的潜在靶点。
