Introduction: The aim of this study was to construct a lentivirus vector with survivin promoter (pSur)-driven apoptin and test its efficiency in suppressing the growth of tumor cells.
Material and methods: Expression cassettes with different fragments of survivin gene promoter (pSur, 161 bp, 272 bp, 990 bp) driving 6XHis-tagged apoptin were constructed to generate recombinant lentivirus, of which the inhibitory effect on tumor cells was compared. The activity of different pSur in 293FT, and 272 bp pSur in primary bone marrow mesenchymal stem cells (BMSCs), SW480, Hela and MCF-7 was examined by Western blot. Their ability to induce apoptosis in SW480 cells was determined by annexin-V staining. The inhibitory effect of letivirus containing different pSur-driven apoptin on nude mice-xenografted SW480 cells was assessed by tumor size and pathological observation.
Results: The 272 bp and 990 bp pSur displayed comparable effects in terms of promoter activity, cell apoptosis/necrosis and G1 phase arrest in vitro, and growth of xenograft tumor in vivo. When lentivirus containing 272 bp pSur was tested, it drove high apoptin expression in tumor cells (SW480, Hela and MCF-7) and weak expression in primary bone marrow mesenchymal stem cells. Xenograft to nude mice using infected Sw480 cells showed that lentiviruses possessing 272 bp and 990 bp pSur were able to significantly induce tumor cell death, focal necrosis, and tumor growth lag.
Conclusions: The data indicated that pSur-apoptin expression cassette in lentivirus vector ensures specific suppression of tumor cells, and may be applicable to monitor malignant transformation of transplanted cells.
Keywords: apoptin; gene therapy; lentivirus; survivin promoter; tumor suppression.