Regression Of B16-F10 Melanoma Tumors After Intratumoral Delivery Of An TRAIL-expressing Plasmid Followed By In Vivo Electroporation And Its Influence On Immune Suppresser Cells

Cancer therapy is widely studied by researchers and in vivo electroporation has been used to efficiently deliver drugs and therapeutic genes to tumors. TNF-related apoptosis inducing ligand (TRAIL) has attracted great attention for its inducing apoptosis in a broad range of tumor cells but not in normal cells. This study focus on the effect of intratumoral delivery of a 30ug pcDNA3.1 plasmid expressing TRAIL on established B16-F10 melanoma tumors by electroporation(60V, 6 pulses) and has significant depression effect on tumor growth compared to the control group. The group with only injection of plasmid does not have much difference compare to the control group, but the group only received electroporation makes the tumor growth faster. We also studied the CD4+CD25+Treg cells and Myeloid Suppresser Cells(MSC) in mice with tumor. There is an increased number of Tregs in tumor in different groups. The group of delivery plasmid by electroporation has the minimum increase of the percentage of Tregs. There is varies number of MSC in the spleen after different disposal. Compared between Day 5 and Day 1 after treatment, the percentage of MSC in the spleen decreases only in the group treated with both plasmid and electroporation .