Cantonero Carlos, Camello Pedro Javier, Abate Carmen, Berardi Francesco, Salido Gines Maria, Rosado Juan Antonio, Redondo Pedro C
Department of Physiology, Phycell and FIMUL Groups, University of Extremadura, 10003 Caceres, Spain.
Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "Aldo Moro", Via Orabona 4, I-70125 Bari, Italy.
Cancers (Basel). 2020 Jan 21;12(2):257. doi: 10.3390/cancers12020257.
(1) Background: The structure of the Sigma 2 receptor/TMEM97 (σ2RTMEM97) has recently been reported. (2, 3) Methods and results: We used genetic and biochemical approaches to identify the molecular mechanism downstream of σ2R/TMEM97. The novel σ2R/TMEM97 fluorescent ligand, NO1, reduced the proliferation and survival of the triple negative breast cancer cell lines (TNBC: MDA-MB-231 and MDA-MB-468 cell lines), due to NO1-induced apoptosis. Greater bioaccumulation and faster uptake of NO1 in MDA-MB-231 cells compared to MCF10A or MCF7 cell lines were also shown. Accordingly, elevated σ2R/TMEM97 expression was confirmed by Western blotting. In contrast to NO1, other σ2R/TMEM97 ligands, such as SM21 and PB28, enhanced MDA-MB-231 cell proliferation and migration. Store-operated calcium entry (SOCE) is crucial for different cancer hallmarks. Here, we show that NO1, but not other σ2R/TMEM97 ligands, reduced SOCE in MDA-MB-231 cells. Similarly, TMEM97 silencing in MDA-MB-231 cells also impaired SOCE. NO1 administration downregulated STIM1-Orai1 interaction, probably by impairing the positive regulatory effect of σ2R/TMEM97 on STIM1, as we were unable to detect interaction with Orai1. (4) Conclusion: σ2R/TMEM97 is a key protein for the survival of triple negative breast cancer cells by promoting SOCE; therefore, NO1 may become a good pharmacological tool to avoid their proliferation.
（1）背景：最近已报道了西格玛2受体/TMEM97（σ2R/TMEM97）的结构。（2,3）方法与结果：我们采用遗传学和生物化学方法来确定σ2R/TMEM97下游的分子机制。新型σ2R/TMEM97荧光配体NO1可降低三阴性乳腺癌细胞系（TNBC：MDA-MB-231和MDA-MB-468细胞系）的增殖和存活率，这是由于NO1诱导了细胞凋亡。与MCF10A或MCF7细胞系相比，MDA-MB-231细胞中NO1的生物蓄积量更高且摄取更快。相应地，通过蛋白质印迹法证实了σ2R/TMEM97表达升高。与NO1相反，其他σ2R/TMEM97配体，如SM21和PB28，可增强MDA-MB-231细胞的增殖和迁移。钙库操纵性钙内流（SOCE）对不同的癌症特征至关重要。在此，我们表明NO1而非其他σ2R/TMEM97配体可降低MDA-MB-231细胞中的SOCE。同样，MDA-MB-231细胞中TMEM97的沉默也损害了SOCE。给予NO1可下调STIM1-Orai1相互作用，可能是通过损害σ2R/TMEM97对STIM1的正向调节作用，因为我们无法检测到与Orai1的相互作用。（4）结论：σ2R/TMEM97是通过促进SOCE来维持三阴性乳腺癌细胞存活的关键蛋白；因此，NO1可能成为一种良好的药理学工具来抑制其增殖。
