Combination Treatment of Carboxyl Esterase 2-Overexpressing hTERT-Immortalized Human Adipose Stem Cells Enhances the Inhibition of Tumor Growth by Irinotecan in PC3, a Castration-Resistant Prostate Cancer Model

초록

Castration-resistant prostate cancer (CRPC) remains difficult to treat with conventional chemotherapy. We evaluated a stem cell-based enzyme-prodrug strategy using hTERT-immortalized adipose-derived stem cells engineered to express rabbit carboxylesterase 2 (hTERT-ADSC.CE2) in combination with irinotecan (CPT-11). hTERT-ADSC.CE2 cells were generated via lentiviral transduction and confirmed to overexpress CE2. Their tumor-homing capacity toward PC3 prostate cancer cells was assessed, along with prodrug activation, apoptosis induction, and in vivo tumor suppression in a CRPC mouse model. hTERT-ADSC.CE2 cells demonstrated enhanced migration toward PC3 cells and higher expression of tumor-homing factors than the controls. Under CPT-11, they exhibited a strong “suicide” effect and induced selective killing of PC3 cells, with upregulation of BAX and cleaved caspase-3 and downregulation of BCL-2. By day 14, the combination arm showed significantly lower tumor burden than both the control and irinotecan-alone arms (p < 0.05). The pattern is consistent with intratumoral activation and localized SN-38 exposure. hTERT-ADSC.CE2 combined with irinotecan provides potent, tumor-targeted cytotoxicity and markedly suppresses CRPC progression. This cell-mediated prodrug activation system may represent a promising therapeutic approach for advanced prostate cancer. © 2025 by the authors.

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