Oncolytic H-1 parvovirus binds to sialic acid on laminins for cell attachment and entry

Abstract

H-1 parvovirus (H-1PV) is a promising anticancer therapy. However, in-depth understanding of its life cycle, including the host cell factors needed for infectivity and oncolysis, is lacking. This understanding may guide the rational design of combination strategies, aid development of more effective viruses, and help identify biomarkers of susceptibility to H-1PV treatment. To identify the host cell factors involved, we carry out siRNA library screening using a druggable genome library. We identify one crucial modulator of H-1PV infection: laminin γ1 (LAMC1). Using loss- and gain-of-function studies, competition experiments, and ELISA, we validate LAMC1 and laminin family members as being essential to H-1PV cell attachment and entry. H-1PV binding to laminins is dependent on their sialic acid moieties and is inhibited by heparin. We show that laminins are differentially expressed in various tumour entities, including glioblastoma. We confirm the expression pattern of laminin γ1 in glioblastoma biopsies by immunohistochemistry. We also provide evidence of a direct correlation between LAMC1 expression levels and H-1PV oncolytic activity in 59 cancer cell lines and in 3D organotypic spheroid cultures with different sensitivities to H-1PV infection. These results support the idea that tumours with elevated levels of γ1 containing laminins are more susceptible to H-1PV-based therapies.

Oncolytic H-1 Parvovirus Hijacks Galectin-1 to Enter Cancer Cells

“…Cervical carcinoma-derived HeLa, pancreatic ductal adenocarcinoma-derived BxPC3, glioma-derived, NCH125, NCH37, U251, LN308, T98G, and A172-MG cell lines were maintained in-house [ 14 ]. The NCH125 LGALS1 KO and NCH125 CRISPR Control cell lines were established in this study (see below- Generation of LGALS1 knockout cell line ).…”

“…The first step of the virus life cycle is the virus recognition of receptor (s), co-receptor (s) or other co-factors on the cell surface modulating host cell entry. In the case of H-1PV and other protoparvoviruses, sialic acid is essential for virus–cell attachment [ 12 , 13 , 14 ]. Recently, we performed a druggable genome-wide siRNA library screen to identify putative modulators of H-1PV infection.…”

“…Characterisation of the interaction between H-1PV and laminin γ1 revealed that laminins, and in particular those containing laminin γ1, play a key role in mediating H-1PV attachment at the cell surface and subsequent entry into cancer cells. H-1PV binding to laminin is dependent on the sialic acid moieties in these molecules [ 14 ]. We have also shown that H-1PV cell uptake occurs through clathrin-mediated endocytosis and that the virus then passes through early to late endosomes prior to entering the nucleus.…”

Tumor-Associated Macrophages in Gliomas—Basic Insights and Treatment Opportunities

“…Clinical trials for anti-PD-1 treatment in combination with radiotherapy (CheckMate 498, ClinicalTrials.gov Identifier: NCT02617589) and chemoradiotherapy (CheckMate548, ClinicalTrials.gov Identifier: NCT02667587) are currently ongoing where nivolumab is being tested in newly diagnosed GBM patients. Owing to the fact that adjuvant Nivolumab before debulking surgery showed promising results [ 120 ], oncolytic virotherapy or suicide gene therapy [ 56 , 144 , 145 , 146 ] in combination with anti-PD-1 treatment could be rational choices. Since PD-1-expression in the TAM compartment is heterogenous and not all TAMs are positive for PD-1 [ 51 ], a second TAM-targeted therapy may also be relevant in this case.…”

Virotherapy in Germany—Recent Activities in Virus Engineering, Preclinical Development, and Clinical Studies

“…In particular, H-1PV binds to sialic acid moieties present in laminins. A direct correlation between H-1PV oncolytic activity and LAMC1 mRNA levels was found in 59 cancer cell lines from different tumor entities, suggesting that tumors with elevated levels of γ1-containing laminins are more susceptible to H-1PV-based therapies [ 49 ]. Second, Marchini’s laboratory found that H-1PV cell internalization occurs via clathrin-mediated endocytosis, a process that is dependent on dynamin.…”