# In Vitro Effects of Extracellular Vesicles from Adipose Tissue-Derived Stem Cells on the Growth and Metastasis of Cultured Breast Cancer Cells via Downregulation of Interleukin-6 Expression and the Microtubule Network

## TL;DR

Stem cell-derived extracellular vesicles can slow breast cancer cell growth and spread by reducing inflammation and disrupting cell structures.

## Contribution

This study demonstrates that extracellular vesicles from adipose stem cells inhibit breast cancer progression via IL-6 suppression and microtubule disruption.

## Key findings

- Extracellular vesicles from adipose stem cells significantly reduced breast cancer cell viability and migration.
- EV treatment downregulated IL-6, IL-6RST, and STAT3 gene expression, and disrupted microtubule networks in cancer cells.
- Immunofluorescence imaging showed disorganized microtubules in EV-treated cells, linked to reduced TubA1 and CALR expression.

## Abstract

Breast cancer is the most common cancer in women worldwide and remains a major cause of death. Scientists are exploring new treatments that go beyond surgery and chemotherapy. This study looked at tiny natural particles called extracellular vesicles, released by fat-derived stem cells, to see how they affect breast cancer cells in the lab. The extracellular vesicles were isolated with high purity and predominantly fell within the nanoscale size range, with an average diameter of 177.1 ± 78.7 nm. When breast cancer cells were treated with these vesicles, their growth and movement slowed, especially at a moderate concentration. The treatment also reduced the levels of molecules linked to inflammation and cancer progression, such as IL-6 and STAT3, and disrupted the internal skeleton that helps cells divide and spread. Under the microscope, cancer cells exposed to the vesicles showed disorganized structures and less stability. These results suggest that substances naturally produced by stem cells might help slow or stop cancer cell growth by blocking harmful signaling and weakening the cell’s internal framework. This research could open the way for new, cell-free treatments that use the body’s own biological materials to fight breast cancer safely and effectively.

Breast cancer remains the most common malignancy worldwide and the leading cause of cancer-related mortality. Recently, extracellular vesicles (EVs) derived from adipose tissue-derived stem cells (ADSCs) have attracted increasing attention for their potential to modulate inflammatory signaling and influence tumor cell behavior. This in vitro study was designed to investigate the effects of ADSC-EVs on MCF-7 breast cancer cells. EVs were isolated from ADSC culture supernatants and applied to MCF-7 cells at concentrations ranging from 0 to 80% (v/v). Cell viability, migration, and expression of IL-6/STAT3 pathway-related genes were evaluated using MTT, scratch assays, and qRT-PCR. Statistical analysis was performed using one-way ANOVA followed by Tukey’s post hoc test, with significance set at p < 0.05. The results showed that 20% EV treatment markedly inhibited MCF-7 cell activity, significantly reducing viability and almost completely blocking migration, with wound closure rates of 35.4% ± 3.80 at 24 h and 47.6% ± 4.2 at 48 h, compared with 48% ± 4.6 and 67% ± 4.2 in the control group, respectively. Notably, expression levels of IL-6, IL-6RST, and STAT3 were significantly downregulated (fold changes 0.155 ± 0.02 and 0.258 ± 0.012, p < 0.01), accompanied by severe disruption of the microtubule network. Immunofluorescence imaging revealed a disorganized microtubule architecture and irregular filament distribution in EV-treated cells, corresponding with decreased expression of TubA1 and CALR genes. These findings indicate that ADSC-EVs not only suppress IL-6/STAT3 inflammatory signaling but also destabilize the intracellular microtubule system, collectively contributing to the inhibition of MCF-7 breast cancer cell migration and survival. This provides an important molecular basis for developing novel EV-based therapeutic strategies in breast cancer treatment.