Piao Shuyu, Kim Seonhee, Vu Giang-Huong, Kim Minsoo, Lee Eun-Ok, Jeon Byeong Hwa, Kim Cuk-Seong
Department of Physiology & Medical Science, College of Medicine, Chungnam National University, Daejeon 301-747, Republic of Korea.
Cancers (Basel). 2024 Dec 5;16(23):4081. doi: 10.3390/cancers16234081.
BACKGROUND/OBJECTIVES: Mitochondrial oxidative phosphorylation (OXPHOS) has been exploited as a therapeutic target in cancer treatments because of its crucial role in tumorigenesis. CR6-interacting factor 1 (CRIF1), a mitochondrial ribosomal subunit protein, is essential for the regulation of mitochondrial OXPHOS capacity. However, the mechanism of CRIF1 in triple-negative breast cancer (TNBC) cells remains unclear.
METHODS/RESULTS: We showed that the downregulation of CRIF1 reduced cell proliferation in the TNBC cell lines MDA-MB-468, MDA-MB-231, and, especially, BT549. In addition, wound scratch and Transwell assays showed that CRIF1 deficiency inhibited the migration and invasion of BT549 cells. CRIF1 downregulation resulted in the suppression of mitochondrial bioenergetics in BT549 cells, specifically affecting the inhibition of OXPHOS complexes I and II. This was evidenced by a decrease in the mitochondrial oxygen consumption rate and the depolarization of the mitochondrial membrane potential. Damage to mitochondria resulted in a lower adenosine triphosphate level and an elevated production of mitochondrial reactive oxygen species. In addition, CRIF1 deficiency decreased hypoxia-inducible factor 1α accumulation, NADPH synthesis, and TP53-induced glycolysis and apoptosis regulator (TIGAR) expression in BT549 cells. These events contributed to G0/G1-phase cell cycle inhibition and the upregulation of the cell cycle protein markers p53, p21, and p16. Transfection with a TIGAR overexpression plasmid reversed these effects and prevented CRIF1 downregulation-induced proliferation and migration reduction.
These results indicate that blocking mitochondrial OXPHOS synthesis via CRIF1 may have a therapeutic antitumor effect in BT549 TNBC cells.
背景/目的：线粒体氧化磷酸化（OXPHOS）因其在肿瘤发生中的关键作用，已被用作癌症治疗的一个靶点。CR6相互作用因子1（CRIF1）是一种线粒体核糖体亚基蛋白，对线粒体OXPHOS能力的调节至关重要。然而，CRIF1在三阴性乳腺癌（TNBC）细胞中的作用机制尚不清楚。
方法/结果：我们发现，CRIF1的下调降低了TNBC细胞系MDA-MB-468、MDA-MB-231，尤其是BT549中的细胞增殖。此外，划痕实验和Transwell实验表明，CRIF1的缺失抑制了BT549细胞的迁移和侵袭。CRIF1的下调导致BT549细胞中线粒体生物能量学的抑制，特别是对OXPHOS复合体I和II的抑制。线粒体氧消耗率的降低和线粒体膜电位的去极化证明了这一点。线粒体损伤导致三磷酸腺苷水平降低和线粒体活性氧生成增加。此外，CRIF1的缺失降低了BT549细胞中缺氧诱导因子1α的积累、NADPH的合成以及TP53诱导的糖酵解和凋亡调节因子（TIGAR）的表达。这些事件导致G0/G1期细胞周期抑制以及细胞周期蛋白标志物p53、p21和p16的上调。转染TIGAR过表达质粒可逆转这些效应，并防止CRIF1下调诱导的增殖和迁移减少。
这些结果表明，通过CRIF1阻断线粒体OXPHOS合成可能对BT549 TNBC细胞具有治疗性抗肿瘤作用。
