Induction of apoptosis in experimental human B cell lymphomas by conditional TRAIL-expressing T cells

Abstract

In the present study, we demonstrate the utility of a non-tumour-forming T-cell line for the inducible gene transfer of tumour necrosis factor (TNF)-related apoptosis-inducing ligand (Apo2L/TRAIL), which has been shown to selectively induce apoptosis in malignant but not in normal cells. To generate T cells inducible for TRAIL expression, we stably transfected Jurkat cells with TRAIL in the context of the Tet-On system. The switched on cells strongly expressed TRAIL mRNA, whose protein product was expressed on the cell surface. Paracrine induction of apoptosis in human target tumour cells was solely found for membrane-bound TRAIL. The Jurkat-TRAIL cells itself survived due to clonal selection of TRAIL-resistant cells. Jurkat-TRAIL cells had an additive effect with cytotoxic drugs in vitro, since cell death was enhanced. To elucidate the antitumoral activity of these Jurkat-TRAIL cells in vivo, we injected them intratumorally in xenografts of human Burkitt lymphomas. Switching on expression of TRAIL by adding tetracycline to the drinking water of the mice strongly reduced tumour growth by apoptosis in a caspase-dependent manner. Thus, non-tumourforming T-cell lines offer a novel method for gene transfer and inducible expression of TRAIL in tumour therapy.

Specific resistance upon lentiviral TRAIL transfer by intracellular retention of TRAIL receptors

“…This finding corresponds to our recent results using stable transfection of a Tet-inducible mammalian expression plasmid for TRAIL. 13 Quite similarly, the tumor cells used in this study also developed specific resistance towards TRAIL-induced apoptosis suggesting that the underlying mechanism may be more common. One might speculate, that it might be a naturally occurring way by which TRAIL-overexpressing cells protect themselves from death by intracellular retention of the respective death receptors.…”

“…13 While generating this cell line, we observed that cells rapidly acquired TRAIL resistance. Similarly, the development of TRAIL resistance has been reported upon repeated administration of recombinant TRAIL or TRAILexpressing Ad over long periods of time.…”

“…Cells were cultured at 371C and 5% CO 2 . BJAB control (co) cells and BJAB cells expressing dominant negative FADD (FADD-DN), 13,45 BL-60 cells, 24 Jurkat JA3 wt, and caspase-8 deficient Jurkat JA3 cells 46 were cultured in complete RPMI. P693 non-small cell lung cancer cells, 47 MIAPACA pancreatic carcinoma cells (kindly provided by H Friess), P5 cervix carcinoma cells, 48 and HEK 293T 49 cells were cultured in complete DMEM.…”

“…LV.TRAIL was constructed by inserting a full-length human TRAIL cDNA 13 in between the CMV promoter and the IRES element. LV.GFPTRAIL was constructed by replacing the IRES-GFP cassette from LV.GFP with the GFP-TRAIL fusion protein cDNA, 57 kindly provided by Dr B Fang, Houston, USA.…”

Apoptosis mediated by lentiviral TRAIL transfer involves transduction-dependent and -independent effects

“…18,19 Moreover, the application of TRAIL expressing cells into tumor-bearing mice, for example, by TRAIL overexpressing neural stem cells or Tet-inducible T cells achieved local production of TRAIL followed by apoptosis. 20,21 However, viral gene transfer using adenoviral or AAV-vectors is only capable of transient gene expression, resulting in the outgrowth of tumors after loss of transgene expression in most cases. HIV-derived VSV-G-pseudotyped lentiviral vectors may overcome this obstacle as they provide efficient gene transfer and are demonstrated to mediate stable, high-level transgene expression both in vitro and in vivo.…”