Complete tumor prevention by engineered tumor cell vaccines employing nonviral vectors

Abstract

We report that 100% mice survival after tumor challenge is achieved with cytokine-engineered cells employing nonviral lipoplexes and without using viral vectors. We describe this effect with cytokine-secreting tumor cell vaccines, based on cell clones or fresh transfected cells. Tumor cells were transfected with murine granulocyte-macrophage colony-stimulating factor (GM-CSF) or IL-4 plasmids employing the cationic lipid DOTAP, were irradiated (150 Gy) and kept frozen until use. The transfection efficacy was analyzed by qRT-PCR and flow cytometry. Vaccination induced potent antitumor rejection, resulting in 100% mice survival. Furthermore, the antitumor immunity was long lasting, since a two-fold survival delay was observed in mice after tumor rechallenge (6 months later). While cell clones secreting GM-CSF were the most effective in wild-type tumor cell rejection, little or no effect was observed with clones secreting IL-4. We found similar antitumor efficacy employing fresh transfected cells by nonviral procedures, demonstrating that cells genetically modified by nonviral vectors (both clones and fresh transfected cells) are a safe and efficient tool for antitumor vaccines. These vaccines allow us to achieve the highest antitumor efficacy based on nonviral gene therapy techniques. In addition, the vaccination success with fresh transfected cells simplifies the procedure and provides new insights into the clinical application of nonviral gene therapy procedures.

Enhanced therapeutic efficacy of IL-12, but not GM-CSF, expressing oncolytic herpes simplex virus for transgenic mouse derived prostate cancers

“…27,[52][53][54][55] Interestingly, many cell vaccination studies for cancer therapy have focused on using GM-CSF as the preferred cytokine of choice based on initial data that identified it to be the best cytokine. [56][57][58][59][60] However, in the initial comparison study IL-12 was not tested, 56 and at least one recent study suggests that very high doses of GM-CSF can result in adverse immunosuppressive effects. 61 Taken together, the above-cited studies suggest that IL-12 might be the better cytokine for inducing a more robust antitumoral immunity.…”

Preclinical study of an ex vivo gene therapy protocol for hepatocarcinoma

“…This effect of irradiation on IL-12 production could be explained by the cytokine leakage from radiation-damaged cells or by a radiation-induced activation of transcription factors. 41,42 This effect on cytokine production seems to be cell-or cytokine-dependent as Rosenthal et al 43 reported a five-fold increase in granulocyte-macrophage colony-stimulating factor production after irradiation of genetically modified murine cells, whereas Moret-Tatay et al 44 reported a decay in RNA production in genetically (granulocyte-macrophage colony-stimulating factor) modified tumor cells. Santin et al 45 reported no effect of irradiation on IL-12 production by the genetically modified human ovarian tumor cells.…”

Gene therapy for hepatocellular carcinoma using sonoporation enhanced by contrast agents

“…29,30 Currently, some studies have reported that commercially available transfection reagents (i.e., Lipoplexes) have proved useful for nonviral gene therapy. [31][32][33][34][35] We too are very interested in these reagents. Nevertheless, we expect that targeted gene therapy by sonoporation using contrast agents for HCC would be a much easier method, based on our experience using contrast agents to detect hepatic tumors by US examination in clinical situations.…”