Tavakkoli Sajjad, Sotoodehnejadnematalahi Fattah, Fathollahi Anwar, Bandehpour Mojgan, Haji Molla Hoseini Mostafa, Yeganeh Farshid
Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Int J Mol Cell Med. 2020 Summer;9(3):207-215. doi: 10.22088/IJMCM.BUMS.9.3.207. Epub 2020 Nov 10.
Exosomes released by tumor cells play critical roles in tumor progression, immune cell suppression, and cancer metastasis. The aim of the present study was to investigate whether the exosomes released by EL4 cells carry a functional TNF-related apoptosis-inducing ligand (TRAIL) molecule. Exosomes were harvested from the supernatants of EL4 cell culture, and the shape, size, and identity of EL4-derived exosomes were evaluated by utilizing scanning electron microscopy, dynamic light scattering, and dot-blot method. The expression of mRNA and TRAIL protein in EL4 cells and EL4-exosomes were investigated using real-time PCR method and dot-blot analysis. Moreover, the effects of EL4-derived exosomes on cell death in a TRAIL-sensitive cell line (4T1) were studied by using flow cytometry (annexin V/propidium iodide (PI) staining) and fluorescent microscopy analyses (acridine orange/ethidium bromide staining). The results showed that EL4 cells continuously and without the need for stimulation, produce exosomes that carry TRAIL protein. In addition, EL4-derived exosomes were capable to induce apoptosis as well as necrosis in 4T1 cells. It was ultimately revealed that EL4 cells express TRAIL protein and release exosomes containing functional TRAIL. Moreover, the released exosomes were able to induce apoptosis and necrosis in a TRAIL-sensitive cell line. Further studies are needed to reveal the potential roles of tumor-derived exosomes in the pathogenesis of cancers.
肿瘤细胞释放的外泌体在肿瘤进展、免疫细胞抑制和癌症转移中发挥着关键作用。本研究的目的是调查EL4细胞释放的外泌体是否携带功能性肿瘤坏死因子相关凋亡诱导配体（TRAIL）分子。从EL4细胞培养上清液中收获外泌体，并利用扫描电子显微镜、动态光散射和斑点印迹法评估EL4来源外泌体的形状、大小和特性。采用实时PCR法和斑点印迹分析研究EL4细胞和EL4外泌体中mRNA和TRAIL蛋白的表达。此外，通过流式细胞术（膜联蛋白V/碘化丙啶（PI）染色）和荧光显微镜分析（吖啶橙/溴化乙锭染色）研究EL4来源外泌体对TRAIL敏感细胞系（4T1）细胞死亡的影响。结果表明，EL4细胞持续且无需刺激即可产生携带TRAIL蛋白的外泌体。此外，EL4来源的外泌体能够诱导4T1细胞凋亡以及坏死。最终发现，EL4细胞表达TRAIL蛋白并释放含有功能性TRAIL的外泌体。此外，释放的外泌体能够在TRAIL敏感细胞系中诱导凋亡和坏死。需要进一步研究以揭示肿瘤来源外泌体在癌症发病机制中的潜在作用。
