Recently, it has been reported that small, non-membranous nanoparticles (NPs), which differ from extracellular vesicles involved in regulating metastasis and invasion, are secreted from several cancer cells. In this study, we reported the identification and characterization of NPs secreted from the prostate cancer cell line PC-3.

After separation of exosomal pellet and supernatant from PC-3 conditioned media by the ultracentrifugation method of Théry et al., the supernatant was ultracentrifuged to collect a pellet (pellet A). Furthermore, the supernatant separated from the pellet A was ultracentrifuged to collect a pellet (pellet B). For each pellet, Structural analysis and Western blot analysis, and real-time PCR analysis of long non-coding RNAs (lncRNAs) associated with prostate cancer progression (i.e., HOXA11-AS, NEAT1, PCAT1) were performed.

Structural analysis showed that exosomal pellet (size: ~180 nm) and the pellet A (~100 nm) exhibited round or oval membranous vesicles. The pellet B exhibited ball-shaped, non-membranous particles (~60 nm). PCR analysis demonstrated differential abundance of these lncRNAs between pellets. The pellet B was enriched with HOXA11-AS and NEAT1, while exosomal pellet had abundant PCAT1.

We characterized PC-3-derived NPs and found that they had prostate cancer-associated lncRNAs.