Cytosine Deaminase-TRAIL Expressing Human Adipose Stem Cells Inhibit Tumor Growth in Castration Resistant Prostate Cancer Bearing Mice with Less Toxicity

Stem cells can selectively migrate toward cancer cells, and therapeutic genes can be introduced into stem cells. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in cancer cells without harming normal cells. In this study, we evaluated the inhibition of tumor growth in castration-resistant prostate cancer (CRPC) using human adipose-derived stem cells (ADSCs) engineered to express cytosine deaminase (CD) and soluble TRAIL (sTRAIL), combined with the prodrug 5-fluorocytosine (5-FC). An immortalized human ADSC line (hTERT-ADSC) was transduced with a lentiviral vector encoding CD and sTRAIL, generating ADSC.CD.sTRAIL cells. Expression of chemoattractant ligands and receptors was assessed by RT-PCR. The suicide gene effect was evaluated by 5-FC treatment, measuring cell viability and apoptosis markers in vitro. A subcutaneous CRPC mouse model was used for in vivo studies. ADSC.CD.sTRAIL cells showed enhanced migration toward prostate cancer cells. Treatment with 5-FC significantly reduced cell viability, and co-culture with PC3 cells plus 5-FC increased apoptosis marker expression. In vivo, mice treated with ADSC.CD.sTRAIL and 5-FC had significantly smaller tumor volumes than control groups, with no treatment-related toxicity observed. These findings suggest that ADSCs overexpressing CD and sTRAIL, combined with 5-FC, effectively inhibit CRPC tumor growth and represent a promising targeted therapeutic strategy.