Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
Life Sci. 2022 Dec 15;311(Pt B):121183. doi: 10.1016/j.lfs.2022.121183. Epub 2022 Nov 12.
Tamoxifen (TAM) selectively modulates estrogen receptors and is widely used in breast cancer treatment. However, resistance to this drug appears in 40 % of estrogen receptor-positive breast cancer patients due to deregulated non-coding RNAs. This study sought to identify a long non-coding-RNA/miRNA/mRNA axis that is involved in the development of resistance to TAM- in MCF7 cells (MCF7-R).
Study genes were selected using RNA-seq. The expression of genes was assessed using TCGA cohort analyses and RT-qPCR. To identify potential resistant pathways in MCF7-R, the DAVID and DIANA-miRPath were carried out. The prediction software (RNAhybrid, TargetScan, and LncTar), and RT-qPCR were used to determine the relationship between genes. Next, the MCF7-R was established and RT-qPCR, cell cycle, apoptosis, and wound healing assays were carried out to verify MCF7-R and identify the effects of CCAT2 overexpression and knockdown on the cells.
Based on bioinformatics analyses, CCAT2, AKT3, and mTOR were up-regulated in breast cancer cell lines, tissues, and TAM-resistant cells, while hsa-miR-145-5p was down-regulated. According to DAVID and DIANA-miRPath, PI3K/AKT/mTOR was a pathway involved in MCF7-R. According to the prediction software, and RT-qPCR results, CCAT2/hsa-miR-145-5p and hsa-miR-145-5p/AKT3 had a negative correlation. CCAT2 knockdown could prevent cell growth, and migration, and promote apoptosis in MCF7-R, while CCAT2 overexpression induced the opposite effects. RT-qPCR revealed that the expression of BAX and Bcl-2 genes were regulated in favor of apoptosis, upon CCAT2 knockdown.
CCAT2 regulates cell cycle, migration, and apoptosis in MCF7-R via the hsa-miR-145-5p/AKT3/mTOR axis. Therefore, CCAT2 may be a target to enhance the sensitivity of resistant MCF7 cells to TAM.
他莫昔芬（TAM）选择性调节雌激素受体，广泛用于乳腺癌治疗。然而，由于非编码 RNA 的失调，40%的雌激素受体阳性乳腺癌患者对这种药物产生耐药性。本研究旨在确定一个长非编码 RNA/miRNA/mRNA 轴，该轴参与 MCF7 细胞（MCF7-R）中 TAM 耐药的发展。
使用 RNA-seq 选择研究基因。使用 TCGA 队列分析和 RT-qPCR 评估基因的表达。为了鉴定 MCF7-R 中的潜在耐药途径，进行了 DAVID 和 DIANA-miRPath 分析。预测软件（RNAhybrid、TargetScan 和 LncTar）和 RT-qPCR 用于确定基因之间的关系。然后，建立 MCF7-R 并进行 RT-qPCR、细胞周期、凋亡和划痕愈合试验，以验证 MCF7-R，并确定 CCAT2 过表达和敲低对细胞的影响。
基于生物信息学分析，CCAT2、AKT3 和 mTOR 在乳腺癌细胞系、组织和 TAM 耐药细胞中上调，而 hsa-miR-145-5p 下调。根据 DAVID 和 DIANA-miRPath，PI3K/AKT/mTOR 是 MCF7-R 涉及的途径。根据预测软件和 RT-qPCR 结果，CCAT2/hsa-miR-145-5p 和 hsa-miR-145-5p/AKT3 呈负相关。CCAT2 敲低可防止 MCF7-R 中的细胞生长、迁移和促进凋亡，而 CCAT2 过表达则诱导相反的效果。RT-qPCR 显示，CCAT2 敲低后，BAX 和 Bcl-2 基因的表达受到调控，有利于凋亡。
CCAT2 通过 hsa-miR-145-5p/AKT3/mTOR 轴调节 MCF7-R 中的细胞周期、迁移和凋亡。因此，CCAT2 可能是增强耐药 MCF7 细胞对 TAM 敏感性的靶点。
