Introduction and objective:
Breast cancer remains a major clinical challenge, with high recurrence rates and the need for safer, more targeted local therapies. Biologic brachytherapy using genetically modified mesenchymal cells offers a promising strategy for localized cytokine delivery. While adipose-derived stem cells (rADSC) have shown potential as carriers of rat TRAIL (rTRAIL), their clinical translation is limited by the need for ex vivo expansion and concerns over tumour-promoting effects.

Material and methods:
The study investigated whether freshly isolated rat stromal vascular fraction (rSVF) cells could be directly transduced with a lentiviral vector to express rTRAIL. Their anticancer activity was compared to rADSC in vitro using co-culture with rat mammary gland cancer cells. The expression was also compared of several markers (CD90, CD44, CD29, CD105, VEGF2, CD31, CD45) between rSVF and rADSC.

Results:
There were no significant differences in the expression of markers between rSVF and rADSC. Both cell types successfully expressed rTRAIL, with rTRAIL-rSVF producing approximately 50% of the TRAIL protein levels observed in rTRAIL-rADSC. In functional assays, rSVF-derived supernatants and co-cultures reduced breast cancer cell viability and colony formation, but the inhibitory effect was approximately 30–50% lower than that of rADSC, depending on the assay and cancer cell line used.

Conclusions:
These findings confirm that rSVF can serve as a transducible and partially effective alternative for rTRAIL delivery and may be valuable for rapid, autologous therapies where culture expansion is not feasible. Further optimization and in vitro validation are needed.