Ferroptosis是一种新型的程序性细胞死亡,这与肿瘤的进展有关。然而,胰腺癌中铁凋亡的调节网络在很大程度上仍是未知的。这里,使用GEO和TCGA的数据集,我们筛选了与P450单加氧酶信号相关的HSPB1,铁性的燃料,是调节胰腺癌细胞铁凋亡的候选基因。我们发现HSPB1富集在源自人胰腺癌细胞系SW1990和Panc-1的外泌体中。然后,缺氧SW1990细胞与外泌体单独或与HSPB1siRNA(si-HSPB1)一起孵育,我们观察到外泌体促进细胞增殖和侵袭,抑制铁凋亡,这被si-HSPB1逆转。此外,我们发现了HSPB1和FUS之间潜在的结合亲和力,通过使用双色荧光共定位和共IP分析验证了它们的蛋白质相互作用,并证明了FUS对低氧SW1990细胞氧化应激和铁凋亡的促进作用。随后,FUS被证明与Nrf2的mRNA结合并稳定Nrf2的mRNA,Nrf2是一种负调节P450水平的著名的抗铁凋亡基因。此外,过表达FUS和激活Nrf2/HO-1途径(使用NK-252)都逆转了si-HSPB1对外泌体功能的抑制作用。最后,我们的体内研究表明,外泌体给药促进异种移植裸鼠的肿瘤生长,能够通过敲低HSPB1来消除。总之,外泌体HSPB1与RNA结合蛋白FUS相互作用,降低FUS介导的Nrf2mRNA的稳定性,从而抑制胰腺癌中缺氧诱导的铁凋亡。
Ferroptosis is a new type of programmed cell death, which has been involved in the progression of tumours. However, the regulatory network of ferroptosis in pancreatic cancer is still largely unknown. Here, using datasets from GEO and TCGA, we screened HSPB1, related to the P450 monooxygenase signalling, a fuel of ferroptosis, to be a candidate gene for regulating pancreatic cancer cell ferroptosis. We found that HSPB1 was enriched in the exosomes derived from human pancreatic cancer cell lines SW1990 and Panc-1. Then, hypoxic SW1990 cells were incubated with exosomes alone or together with HSPB1 siRNA (si-HSPB1), and we observed that exosomes promoted cell proliferation and invasion and suppressed ferroptosis, which was reversed by si-HSPB1. Moreover, we found a potential binding affinity between HSPB1 and
FUS, verified their protein interaction by using dual-colour fluorescence colocalization and co-IP assays, and demonstrated the promoting effect of
FUS on oxidative stress and ferroptosis in hypoxic SW1990 cells. Subsequently,
FUS was demonstrated to bind with and stabilize the mRNA of Nrf2, a famous anti-ferroptosis gene that negatively regulates the level of P450. Furthermore, overexpressing
FUS and activating the Nrf2/HO-1 pathway (using NK-252) both reversed the inhibitory effect of si-HSPB1 on exosome functions. Finally, our in vivo studies showed that exosome administration promote tumour growth in nude mice of xenotransplantation, which was able to be eliminated by knockdown of HSPB1. In conclusion, exosomal HSPB1 interacts with the RNA binding protein
FUS and decreases
FUS-mediated stability of Nrf2 mRNA, thus suppressing hypoxia-induced ferroptosis in pancreatic cancer.