# Exosome-transmitted long noncoding RNA SNHG1 promotes prostate cancer bone metastasis via YBX1/MMP16 axis

## TL;DR

This study shows that a specific noncoding RNA in exosomes from prostate cancer cells promotes bone metastasis by influencing bone cell activity.

## Contribution

The novel contribution is identifying the SNHG1/YBX1/MMP16 axis as a mechanism through which exosomal lncRNA promotes prostate cancer bone metastasis.

## Key findings

- Exosomal SNHG1 is overexpressed in prostate cancer tissues and correlates with bone metastasis.
- SNHG1 transferred via exosomes promotes osteoblast differentiation and extracellular matrix mineralization.
- SNHG1 binds to YBX1, enhances MMP16 transcription, and facilitates prostate cancer bone metastasis.

## Abstract

Prostate cancer (PCa) patients with bone metastasis commonly exhibit osteoblastic-type and have an extremely poor prognosis. Exosomes derived from tumor cells possess biological significance and can mediate intercellular communication in the tumor microenvironment. Long noncoding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) is implicated in tumorigenesis and the development of PCa, but the precise roles of SNHG1 in the regulation of bone homeostasis remain elusive. Herein, we aimed to investigate the underlying mechanisms by which exosomes-encapsulated SNHG1 affects the bone metastasis of PCa. Our findings revealed that SNHG1 was overexpressed in PCa tissues, highly enriched in PCa cell-derived exosomes, and positively correlated with bone metastasis. Besides, SNHG1 shuttled by PCa-derived exosomes could be transferred into osteoblast cells, where SNHG1 exerted inductive properties in osteogenic differentiation. Gain- and loss-of-functional experiments demonstrated that exosomal SNHG1 facilitated the activity of alkaline phosphatase and mineralization of extracellular matrix. Moreover, in vivo experimentation showed that knockdown of exosomal SNHG1 suppressed bone metastasis of PCa cells. Mechanistic investigations revealed that exosomal SNHG1, transmitted to osteoblast cells, physically binds to YBX1 and leads to the shift of YBX1 into the nucleus, then enhances MMP16 transcription and increases the amount of protein translation, ultimately resulting in PCa bone metastasis. In conclusion, our data highlight that PCa-derived exosomes-loaded SNHG1 mediated osteogenesis through the SNHG1/YBX1/MMP16 axis. SNHG1 may serve as a potential diagnostic marker and therapeutic target for bone metastasis in PCa.