Rosuvastatin Enhances VSV-G Lentiviral Transduction of NK Cells via Upregulation of the Low-Density Lipoprotein Receptor

Abstract

Adoptive natural killer (NK) cell therapy is attaining promising clinical outcomes in recent years, but improvements are needed. Genetic modification of NK cells with a tumor antigen-specific receptor on their surface coupled to intracellular signaling domains may lead to enhanced cytotoxicity against malignant cells. One of the most common approaches is by lentivirus-mediated transduction. However, NK cells are difficult to transduce and various methods have been attempted with different success rates. Because the low-density lipoprotein-receptor (LDLR) is the receptor of vesicular stomatitis virus (VSV) and is expressed only at low levels on NK cells, we tested the potential of 5 statins and 5 non-statin compounds to increase the LDLR expression, thereby facilitating viral transduction. We found that the transduction efficiency of VSV-G pseudotyped lentivirus is augmented by statins that induced higher LDLR expression. In both NK-92 cells and primary NK cells, the transduction efficiency increased after treatment with statins. Furthermore, statins have been reported to suppress NK cell cytotoxicity; however, we showed that this can be completely reversed by adding geranylgeranyl-pyrophosphate (GGPP). Among the statins tested, we found that the combination of rosuvastatin with GGPP most potently improved viral transduction without affecting the cytotoxic properties of the NK cells.

Materials promoting viral gene delivery

“…Genetically modified natural killer cells can, for example, express tumor antigen-specific receptors, which may pave the way for targeted treatment of malignant cells. 526 Small molecules, which are beneficial for disease treatment, eliciting host immune response while enabling efficient transduction are actively being pursued for clinical application. Pharmaceutically active drugs that have been found so far, are paving the way especially for oncolytic gene therapy and can be included easily in ex vivo gene transfer protocols.…”

Chimeric antigen receptor natural killer (CAR-NK) cell design and engineering for cancer therapy

“…Interestingly, statins that are used in the clinic to lower blood cholesterol levels were shown to induce LDLR on B and T lymphocytes [ 123 ]. Similarly, we found that statins also induced LDLR levels in NK-92 and primary NK cells [ 93 ]. Consequently, transduction efficiency increased after treatment with statins.…”

“…However, statins have also been reported to suppress the cytotoxic capacity of NK cells, which can be completely reversed by geranylgeranyl-pyrophosphate (GGPP). Not all statins are potent boosters of viral transduction: Rosuvastatin in combination with GGPP most potently improved viral transduction without affecting the cytotoxic properties of the NK cells [ 93 ].…”

“…Phorbol 12-myristate 13-acetate (PMA) [ 127 ], rapamycin [ 128 ], Cyclosporin A [ 129 ], P338 poloxamer [ 130 ], prostaglandin E2 (PGE2) [ 131 ], vectofusin-1 [ 132 ] and RetroNectin [ 92 ] have all been reported to promote lentiviral transduction on hematopoietic stem cell (HSC), T cells or B cells. However, in our analysis on the effects of these compounds on NK cell transduction, we found that only statins consistently promote viral transduction without major negative effects on cell viability [ 93 ].…”

“…VSV-G lentiviruses have also been used to generate genetically modified NK cells for decades, and make stable NK cells line [ 135 , 136 ]. However, as alluded to above, the low expression levels of the VSV-G receptor LDLR on fresh human NK cell hinder efficient and easy lentiviral transduction of NK cells [ 93 , 94 ]. As an alternative to boosting LDLR expression levels, other glycoproteins can be used to pseudotype the viral particle [ 121 ].…”