Ferroptosis, an iron-dependent form of cell death, and dysregulated microRNA (miRNA) expression correlate with colorectal cancer (CRC) development and progression. The tumor suppressor ability of miR-148a-3p has been reported for several cancers. Nevertheless, the role of miR-148a-3p in CRC remains largely undetermined. Here, we aim at investigating the molecular mechanisms and regulatory targets of miR-148a-3p in the CRC cell death mechanism(s). To this end, miR-148a-3p expression was evaluated in SW480 and SW620 cells and normal colon epithelial CCD 841 CoN cells with quantitative real-time polymerase chain reaction (qRT-PCR). Data reported a reduction of miR-148a-3p expression in SW480 and SW620 cells compared to non-tumor cells (p< 0.05). Overexpression of miR-148a selectively inhibited CRC cell viability (p< 0.001), while weakly affecting normal CCD 841 CoN cell survival (p< 0.05). At the cellular level, miR-148a-3p mimics promoted apoptotic cell death via caspase-3 activation (p< 0.001), accumulation of mitochondrial reactive oxygen species (ROS) (p< 0.001), and membrane depolarization (p< 0.001). Moreover, miR-148a-3p overexpression induced lipid peroxidation (p< 0.01), GPX4 downregulation (p< 0.01), and ferroptosis (p< 0.01), as revealed by intracellular and mitochondrial iron accumulation and ACSL4/TFRC/Ferritin modulation. In addition, levels of SLC7A11 mRNA and protein, the cellular targets of miR-148a-3p predicted by bioinformatic tools, were suppressed by miR-148a-3p’s overexpression. On the contrary, the downregulation of miR-148a-3p boosted SLC7A11 gene expression and suppressed ferroptosis. Together, these in vitro findings reveal that miR-148a-3p can function as a tumor suppressor in CRC by targeting SLC7A11 and activating ferroptosis, opening new perspectives for the rationale of therapeutic strategies through targeting the miR-148a-3p/SLC7A11 pathway.
铁死亡作为一种铁依赖性的细胞死亡形式，以及失调的微小RNA（miRNA）表达与结直肠癌（CRC）的发生发展密切相关。已有研究报道miR-148a-3p在多种癌症中具有肿瘤抑制功能，但其在结直肠癌中的作用机制尚未明确。本研究旨在探讨miR-148a-3p在结直肠癌细胞死亡机制中的分子作用及其调控靶点。通过实时定量聚合酶链反应（qRT-PCR）检测发现，与正常结肠上皮细胞CCD 841 CoN相比，SW480和SW620细胞中miR-148a-3p表达水平显著降低（p<0.05）。过表达miR-148a能选择性抑制结直肠癌细胞活力（p<0.001），而对正常CCD 841 CoN细胞存活率影响较小（p<0.05）。在细胞层面，miR-148a-3p模拟物通过激活caspase-3（p<0.001）、促进线粒体活性氧积累（p<0.001）和膜电位去极化（p<0.001）诱导细胞凋亡。此外，miR-148a-3p过表达可引发脂质过氧化（p<0.01）、GPX4下调（p<0.01）及铁死亡（p<0.01），具体表现为细胞内和线粒体铁积累以及ACSL4/TFRC/铁蛋白的调控变化。生物信息学预测显示SLC7A11是miR-148a-3p的潜在靶点，实验证实miR-148a-3p过表达能显著抑制SLC7A11的mRNA和蛋白水平。相反，抑制miR-148a-3p表达可促进SLC7A11基因表达并阻断铁死亡。综上，这些体外实验结果表明，miR-148a-3p通过靶向抑制SLC7A11并激活铁死亡途径，在结直肠癌中发挥肿瘤抑制作用，这为靶向miR-148a-3p/SLC7A11通路的治疗策略提供了新的理论依据。
MiR-148a-3p Promotes Colorectal Cancer Cell Ferroptosis by Targeting SLC7A11
肿瘤(癌症)患者之家