Linh Thuy Nguyen

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.

This study reports the construction and validation of a CAFLUX (Chemically Activated Fluorescent Expression) HepG2 reporter cell line engineered to express a histone H2B–green fluorescent protein (H2B–GFP) fusion protein under the control of a dioxin-responsive cytochrome P450 1A1 (CYP1A1) promoter. A lentiviral construct containing a synthetic promoter with multiple dioxin-responsive elements (DREs) upstream of the H2B–EGFP coding sequence was cloned into the pFUGW vector, packaged in human embryonic kidney (HEK) 293FT cells, and used to transduce HepG2 hepatocellular carcinoma cells. Stable clones obtained by limiting dilution were screened for GFP expression in response to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The resulting CAFLUX HepG2 cells exhibited dose-dependent nuclear GFP fluorescence when exposed to aryl hydrocarbon receptor (AhR) agonists, with limits of detection of approximately 0.01 pM for TCDD and 0.1 pM for benzo[a]pyrene (B[a]P), a polycyclic aromatic hydrocarbon (PAH). This reporter activity correlated with endogenous CYP1A1 mRNA expression as determined by quantitative polymerase chain reaction (qPCR), confirming that GFP signals reflected native transcriptional responses. In functional assays, curcumin suppressed GFP expression in a concentration-dependent manner and induced apoptotic morphology at higher doses, while extracellular vesicles (EVs) derived from adipose-derived stem cells (ADSCs) significantly reduced both GFP fluorescence and CYP1A1 mRNA levels, suggesting an inhibitory effect on AhR-driven transcription. The CAFLUX HepG2 reporter system therefore provides a sensitive and reproducible platform for real-time, nuclear-localized monitoring of AhR-mediated gene expression. Its responsiveness to both agonists and antagonists underscores its potential utility in toxicological evaluation, drug discovery, and the investigation of EV-mediated signaling in liver cancer models.