Department of Hepatopancreatobiliary Surgery, Harbin Medical University Cancer Hospital, Harbin 150081, Heilongjiang, China.
Aging (Albany NY). 2020 Jun 4;12(11):10427-10440. doi: 10.18632/aging.103268.
Pancreatic cancer (PC) is one of the deadliest cancers worldwide. Cancer cells secrete excessive numbers of exosomes that play essential roles in tumorigenesis. Long non-coding RNAs (lncRNAs) are essential non-coding RNAs for cancer progression. However, the role of lncRNA plasmacytoma variant translocation 1 (PVT1) in exosome secretion of PC remains to be comprehensively investigated. Thus, nanoparticle tracking analysis and transmission electron microscopy were performed to determine exosome secretion. Confocal microscopy, western blots, real-time PCR, immunofluorescence, pull-down and RNA immunoprecipitation assays, and rescue experiments were applied to investigate the mechanism underlying the role of PVT1 in exosome secretion. The results showed that PVT1 was upregulated in PC cells, along with increased levels of YKT6 v-SNARE homolog (YKT6), ras-related protein Rab-7 (RAB7), and vesicle-associated membrane protein 3 (VAMP3). Also, PVT1 promoted the transportation of multivesicular bodies (MVBs) towards the plasma membrane. In addition, PVT1 promoted the docking of MVBs by altering RAB7 expression and localization. Moreover, PVT1 promoted the fusion of MVBs with the plasma membrane through regulating YKT6 and VAMP3 colocalization and the palmitoylation of YKT6. Taken together, the results suggest that PVT1 promoted exosome secretion of PC cells and thus, can expand the understanding of PVT1 in tumor biology.
胰腺癌（PC）是全球最致命的癌症之一。癌细胞会分泌过多的外泌体，这些外泌体在肿瘤发生中起着至关重要的作用。长链非编码 RNA（lncRNA）是癌症进展所必需的非编码 RNA。然而，lncRNA 浆细胞瘤变异易位 1（PVT1）在 PC 中外泌体分泌中的作用仍需全面研究。因此，进行了纳米颗粒跟踪分析和透射电子显微镜检查以确定外泌体的分泌。共聚焦显微镜、western blot、实时 PCR、免疫荧光、下拉和 RNA 免疫沉淀实验以及挽救实验用于研究 PVT1 在 exosome 分泌中的作用机制。结果表明，PC 细胞中 PVT1 上调，同时 YKT6 v-SNARE 同源物（YKT6）、ras 相关蛋白 Rab-7（RAB7）和囊泡相关膜蛋白 3（VAMP3）水平也升高。此外，PVT1 通过改变 RAB7 表达和定位促进多泡体（MVB）向质膜的运输。此外，PVT1 通过调节 YKT6 和 VAMP3 共定位以及 YKT6 的棕榈酰化来促进 MVB 与质膜的融合。总之，这些结果表明 PVT1 促进了 PC 细胞的外泌体分泌，从而可以扩大对 PVT1 在肿瘤生物学中的认识。
