# m6A RNA Methylation Promotes the Melanoma Metastasis Mediated by Extracellular Vesicle miR-23a-5p

## TL;DR

This study shows how aggressive melanoma cells use tiny packages to transfer molecules that make less aggressive cells more invasive.

## Contribution

The study identifies miR-23a-5p in extracellular vesicles as a driver of melanoma metastasis through m6A RNA modification.

## Key findings

- Highly metastatic melanoma cells transfer miR-23a-5p via extracellular vesicles to less aggressive cells.
- miR-23a-5p reduces METTL14 levels, altering m6A modifications and silencing tumor suppressor genes Mtus1 and Prrg4.
- This process increases the invasive behavior of recipient melanoma cells.

## Abstract

Melanoma is an aggressive skin cancer with a high tendency to metastasize. This study reveals that highly metastatic melanoma cells can enhance the metastatic ability of less aggressive tumor cells by sending extracellular vesicles (EVs) containing a molecule called miR-23a-5p. Once inside the recipient cells, miR-23a-5p reduces levels of the protein METTL14, which alters m6A modifications on RNA and silences two tumor suppressor genes, Mtus1 and Prrg4. This process ultimately increases the invasive behavior of melanoma cells. These findings provide new insights into how tumor cells communicate to drive metastasis and suggest potential targets for future diagnosis and therapy.

Background/Objectives: Melanoma, characterized by high rates of metastasis and recurrence, is a particularly aggressive malignant tumor. The underlying mechanisms driving its progression remain enigmatic. The close interplay between tumor and non-tumor cells is pivotal, significantly shaping the tumor microenvironment. Extracellular vesicles emerge as a crucial vector influencing this environment, as they can modulate cellular mechanisms and biological functions—marking a key frontier in tumor mechanism research. However, the potential impact of intercellular communication on tumor cell biology remains largely unexplored. Methods: In the study, we employed a pair of cell lines derived from melanoma M14 cells, designated as highly metastatic cells (POL cells) and the low metastatic cells (OL cells), and elucidate their characteristics. Results: Our findings revealed that POL cells can potentiate the metastatic potential of OL cells through the transfer of extracellular vesicles, which harbor functional microRNAs, specifically miR-23a-5p in this context. Upon entering OL cells, the EV-miR-23a-5p orchestrates changes in the m6A modification levels of the mRNA of tumor suppressor genes Mtus1 and Prrg4. Conclusions: This modulation subsequently influences the expression of these genes and, in turn, the invasive behavior of OL cells.