The oncolytic herpes simplex virus (HSV) that has been approved for clinical practice and those HSVs in clinical trials are attenuated viruses, often with the neurovirulence gene 134.5 and additional genes deleted. One strategy to engineer nonattenuated oncolytic HSVs consists of retargeting the viral tropism to a cancer-specific receptor of choice, exemplified by HER2 (human epidermal growth factor receptor 2), which is present in breast, ovary, and other cancers, and in detargeting from the natural receptors. Because the HER2-retargeted HSVs strictly depend on this receptor for infection, the viruses employed in preclinical studies were cultivated in HER2-positive cancer cells. The production of clinical-grade viruses destined for humans should avoid the use of cancer cells. Here, we engineered the R-213 recombinant, by insertion of a 20-amino-acid (aa) short peptide (named GCN4) in the gH of R-LM113; this recombinant was retargeted to HER2 through insertion in gD of a single-chain antibody (scFv) to HER2. Next, we generated a Vero cell line expressing an artificial receptor (GCN4R) whose N terminus consists of an scFv to GCN4 and therefore is capable of interacting with GCN4 present in gH of R-213. R-213 replicated as well as R-LM113 in SK-OV-3 cells, implying that addition of the GCN4 peptide was not detrimental to gH. R-213 grew to relatively high titers in Vero-GCN4R cells, efficiently spread from cell to cell, and killed both Vero-GCN4R and SK-OV-3 cells, as expected for an oncolytic virus. Altogether, Vero-GCN4R cells represent an efficient system for cultivation of retargeted oncolytic HSV in non-cancer cells.
A strategy for cultivation of retargeted oncolytic herpes simplex viruses in non-cancer cells
LEONI, VALERIO;GATTA, VALENTINA;CASIRAGHI, COSTANZA;PETROVIC, BILJANA;CAMPADELLI, MARIA GABRIELLA
2017
Abstract
The oncolytic herpes simplex virus (HSV) that has been approved for clinical practice and those HSVs in clinical trials are attenuated viruses, often with the neurovirulence gene 134.5 and additional genes deleted. One strategy to engineer nonattenuated oncolytic HSVs consists of retargeting the viral tropism to a cancer-specific receptor of choice, exemplified by HER2 (human epidermal growth factor receptor 2), which is present in breast, ovary, and other cancers, and in detargeting from the natural receptors. Because the HER2-retargeted HSVs strictly depend on this receptor for infection, the viruses employed in preclinical studies were cultivated in HER2-positive cancer cells. The production of clinical-grade viruses destined for humans should avoid the use of cancer cells. Here, we engineered the R-213 recombinant, by insertion of a 20-amino-acid (aa) short peptide (named GCN4) in the gH of R-LM113; this recombinant was retargeted to HER2 through insertion in gD of a single-chain antibody (scFv) to HER2. Next, we generated a Vero cell line expressing an artificial receptor (GCN4R) whose N terminus consists of an scFv to GCN4 and therefore is capable of interacting with GCN4 present in gH of R-213. R-213 replicated as well as R-LM113 in SK-OV-3 cells, implying that addition of the GCN4 peptide was not detrimental to gH. R-213 grew to relatively high titers in Vero-GCN4R cells, efficiently spread from cell to cell, and killed both Vero-GCN4R and SK-OV-3 cells, as expected for an oncolytic virus. Altogether, Vero-GCN4R cells represent an efficient system for cultivation of retargeted oncolytic HSV in non-cancer cells.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
