Gene therapy in B-NHL cell line using adenovirus-mediated transfer of secretable trimeric TRAIL gene expression driven by CD20 promoter.

CD20 is a crucial target to B-non-Hodgkin lymphoma (NHL), in fact, a humanized anti-CD20 monoclonal antibody, rituximab, is widely applied in clinical practice. However, resistance to rituximab often occurs in B-NHL patients, which has encouraged us to find new medications to treat B-NHL. In this study, we designed a gene therapy strategy targeting CD20 at a transcriptional level mediated by adenovirus, in which the stTRAIL gene was driven by a specific CD20 promoter fragment. We cloned the CD20 promoter from genome DNA of BJAB cell, a CD20-positive cell line, and identified its specific transcriptional activity with a dual-luciferase reporter assay system. Meanwhile, we constructed the stTRAIL gene sequence, which contained secretion signal, isoleucine zipper, and soluble TRAIL gene sequence, in which the isoleucine zipper facilitated the product of this gene sequence to form a functional homotrimer. The recombinant adenovirus was termed as AdP20-stTRAIL, which carried on the fused gene of the CD20 promoter fragment and the stTRAIL gene. Our studies confirmed that the stTRAIL could be expressed and secreted from BJAB cells infected with AdP20-stTRAIL specifically, and it inhibited the growth of these infected BJAB cells in vitro and in vivo. Our results indicate that the gene therapy using stTRAIL gene driven by a CD20 promoter may be an effective strategy in B-NHL treatment.