Epithelial–Mesenchymal Transition Enhances Response to Oncolytic Herpesviral Therapy Through Nectin-1

Abstract

Cancers exhibiting epithelial-mesenchymal transition (EMT) are associated with aggressive behavior and increased metastatic potential. Therapies that are able to target EMT would have significant clinical value. Nectin-1 is a cell surface herpes simplex virus type 1 (HSV-1) receptor that also forms a component of intercellular adherens junctions, which are typically disrupted in EMT. To explore relationships between HSV-1 sensitivity and EMT, we generated cell lines with a stable EMT phenotype from human follicular thyroid cancer (WRO82-1) through E-cadherin silencing with short hairpin RNA (shEcadWRO). HSV-1 viral attachment and gene expression were both enhanced in shEcadWRO as compared with shControl. Immunoblotting and immunostaining revealed enhanced nectin-1 expression by shEcadWRO. Receptor-blocking assays demonstrated that increased herpesviral entry into shEcadWRO as compared with shControl was mediated predominantly through nectin-1. Colocalization of green fluorescent protein-tagged HSV-1 and tdTomato-tagged nectin-1 confirmed an increase in viral attachment to nectin-1 in shEcadWRO. Cell viability assays demonstrated increased susceptibility of shEcadWRO to HSV-1 oncolysis, and a murine flank tumor model showed significantly enhanced regression of shEcadWRO tumors in response to oncolytic HSV-1 as compared with control tumors. A separate model of EMT induction through transforming growth factor-b stimulation confirmed enhanced HSV-1 susceptibility in Panc1 cells. These results demonstrate that the process of EMT leads to increased herpesviral susceptibility through enhanced cell surface nectin-1 expression, suggesting that cancers exhibiting EMT may be naturally sensitive targets for herpesviral therapy.

Assessment of oncolytic HSV efficacy following increased entry-receptor expression in malignant peripheral nerve sheath tumor cell lines

“…We conclude that the primary mode of MPNST resistance to Δγ 1 34.5 oHSVs is not due to limited expression of nectin-1. Despite the primary conclusions of previously published work that entry-receptor expression is predictive of a productive infection by oHSV, we suggest that the use of viruses in these previous studies which contained at least one functional copy of the γ 1 34.5 gene (NV1023) 14,15,18 or γ 1 34.5 under a nestin promoter (rQnestin34.5) 16 is in line with our conclusions that viruses which are genetically competent to counter the intrinsic antiviral response benefit the most from increased entry-receptor expression. Similarly in our work, the wt HSV-1 and C134 viruses derived greater benefit from higher entry-receptor expression than did the first-generation Δγ 1 34.5 oHSVs.…”

“…14–18 Four viral glycoproteins (gD, gB and gH/gL) and a cellular glycoprotein D (gD)-interacting receptor have been demonstrated as necessary and sufficient to trigger cellular entry. 19–23 Of the three cellular HSV-1 gD-interacting receptors, nectin-1, a cellular adhesion protein expressed in epithelial cells, 24 fibroblasts and neurons, 25 has been proposed as the major HSV-1 entry receptor.…”

Engineered Herpes Simplex Viruses for the Treatment of Malignant Peripheral Nerve Sheath Tumors

“…We conclude that the primary mode of MPNST resistance to Δγ 1 34.5 oHSVs is not due to limited expression of nectin-1. Despite the primary conclusions of previously published work that entryreceptor expression is predictive of a productive infection by oHSV, we suggest that the use of viruses in these previous studies which contained at least one functional copy of the γ 1 34.5 gene (NV1023) 14,15,18 or γ 1 34.5 under a nestin promoter (rQnestin34.5) 16 is in line with our conclusions that viruses which are genetically competent to counter the intrinsic antiviral response benefit the most from increased entry-receptor expression. Similarly in our work, the wt HSV-1 and C134 viruses derived greater benefit from higher entry-receptor expression than did the first-generation Δγ 1 34.5 oHSVs.…”

“…In our initial investigation into potential oHSV resistance mechanisms within MPNSTs, we have tested the hypothesis that oHSV resistance is attributable to the insufficient expression of HSV-1 entry receptors by tumor cells. [14][15][16][17][18] Four viral glycoproteins (gD, gB and gH/gL) and a cellular glycoprotein D (gD)-interacting receptor have been demonstrated as necessary and sufficient to trigger cellular entry. [19][20][21][22][23] Of the three cellular HSV-1 gD-interacting receptors, nectin-1, a cellular adhesion protein expressed in epithelial cells, 24 fibroblasts and neurons, 25 has been proposed as the major HSV-1 entry receptor.…”

Identification of SSEA-1 expressing enhanced reprogramming (SEER) cells in porcine embryonic fibroblasts

“…33 In addition, we found genes that have been shown to be important in the epithelial-mesenchymal transition (PVRL1, THBS1, MMP-13). [34][35][36] Given the background of these genes, we proposed that the SSEA-1C cell population may have a slightly different identity expressing higher levels of genes found in mesenchymal stem cells and mesoderm/mesendoderm.…”