OBJECTIVETo explore bone marrow-derived mesenchymal stem cells (BMSC) mediated gene directed enzyme prodrug targeting anti-tumor therapy (GDEPT).

METHODSCYP1A2 gene was cloned from human hepatocytes by RT-PCR, and the eukaryote expression vector was constructed and transferred into Raji cells and human BMSCs via liposome. The targeted anti-tumor effect of BMSC-CYP1A2 cooperated with dacarbazine (DTIC) was measured. RT-PCR and Western blot were used to detect the expression of CYP1A2. Migration assay was detected with Transwell Plates. MTT was used to evaluate the growth inhibitory effect. Cell apoptosis was determined with Annexin V-FITC/PI staining by flow cytometry(FCM).

RESULTSThe results of FCM and differentiation induction were in line with the characteristics of BMSC. The expression of CYP1A2 was confirmed by RT-PCR and Western blot. Growth inhibition of Raji-CYP1A2 cells was increased with DTIC concentration in a dose-dependent manner (IC(50) was 1.67 mmol/L). However, BMSC was less sensitive to the cytotoxic effects of DTIC (IC(50) of 9.26 mmol/L and 7.53 mmol/L for BMSC-pcDNA3.1 and BMSC-CYP1A2 cells, respectively) than Raji cells did (IC(50) of 5.62 mmol/L and 1.67 mmol/L for Raji-pcDNA3.1 and Raji-CYP1A2 cells, respectively). BMSC migrated toward Raji cells in Transwell plate. BMSC-CYP1A2 cells mediated a bystander killing effect for CYP1A2-negative Raji cells when they were co-cultured with BMSC-CYP1A2 cells.

CONCLUSIONDTIC can be catalyzed by CYP1A2 in vitro. BMSC-based enzyme prodrug system of CYP1A2 and DTIC can induce lymphoma cell apoptosis targetedly via bystander killing effect.