Genetically engineered attenuated measles virus specifically infects and kills primary multiple myeloma cells

Abstract

The applicability of cytoreductive treatment of malignant diseases using recombinant viruses strongly depends on specific recognition of surface receptors to target exclusively neoplastic cells. A recently generated monoclonal antibody (mAb), Wue-1, specifically detects CD138 + multiple myeloma (MM) cells. In this study, a haemagglutinin (H) protein that was receptor-blinded (i.e. did not bind to CD46 and CD150) was genetically re-engineered by fusing it to a single-chain antibody fragment (scFv) derived from the Wue-1 mAb open reading frame (scFv-Wue), resulting in the recombinant retargeted measles virus (MV)-Wue. MV-Wue efficiently targeted and fully replicated in primary MM cells, reaching titres similar to those seen with non-retargeted viruses. In agreement with its altered receptor specificity, infection of target cells was no longer dependent on CD150 or CD46, but was restricted to cells that had been labelled with Wue-1 mAb. Importantly, infection with MV-Wue rapidly induced apoptosis in CD138 + malignant plasma cell targets. MV-Wue is the first fully retargeted MV using the restricted interaction between Wue-1 mAb and primary MM cells specifically to infect, replicate in and deplete malignant plasma cells.

Attenuated Oncolytic Measles Virus Strains as Cancer Therapeutics

“…Thus, retargeting procedures can focus on H protein modifications without significantly affecting the considerable fusogenic capacity of the virus. Accordingly, a large number of studies have shown that fully retargeted MV-Edm strains demonstrate no significant attenuation of oncolytic efficacy against cells or xenografts expressing adequate levels of target receptors [43, 45, 47, 48, 50, 55, 79]. Following identification of aminoacid residues necessary for H interaction with CD46 and SLAM [24] it was determined that full retargeting may be optimally accomplished by a single CD46-ablating substitution of tyrosine by alanine at position 481 (Y481A) and a single SLAM-ablating substitution of arginine by alanine at position 533 [24, 36, 47, 80] in combination with display of targeting ligands on the C-terminus of the H protein [36, 37, 81] (Figure 1C).…”

“…Following identification of aminoacid residues necessary for H interaction with CD46 and SLAM [24] it was determined that full retargeting may be optimally accomplished by a single CD46-ablating substitution of tyrosine by alanine at position 481 (Y481A) and a single SLAM-ablating substitution of arginine by alanine at position 533 [24, 36, 47, 80] in combination with display of targeting ligands on the C-terminus of the H protein [36, 37, 81] (Figure 1C). Construction of a wide variety of retargeted oncolytic MV-Edm derivatives has been successfully accomplished, including viruses displaying single chain antibodies against CD38 [26, 36, 37], EGFR [36, 37, 48], EGFRvIII [36, 47], alpha-folate receptor [45], HER2/neu [43], CD20 [39, 40], CEA [58, 82], PSMA [60] and the Wue-1 ligand [79]. Retargeted oncolytic MVs have also been constructed to display the snake venom peptide echistatin [41], cyclic arginine-glycine-aspartate (RGD) [78], single-chain T cell receptors [83] as well as cytokines such as IL-13 [50] and peptide ligands to the urokinase receptor (uPAR) [55].…”

“…These viruses are highly stable with very low recombination rates [35]. In addition, full transductional retargeting of MV-Edm is feasible using a wide variety of targets [26, 36, 39–41, 43, 44, 47, 48, 50, 55, 58, 60, 66, 78, 79, 81–83]. The natural fusogenicity of measles strains induces a potent additional bystander effect [14–18] and may also be utilized in immune evasion strategies using cell carriers [53, 56, 87–91].…”

Antibody neutralization of retargeted measles viruses

“…Retargeted recombinant oncolytic measles virus derivatives used in this study (figure 1) have been characterized previously: MV-H-EGFR.scFv (MV-H6-H AALS -αEGFR) [29]; MV-H-Ech (MV-ERV) [41]; MV-H-Wue.scFv (MV-Wue) [35]. The control virus MV-Hedm will have a similar susceptibility to monoclonal anti-H antibodies and anti-MV antibodies present in human serum as oncolytic MVs tested clinically [100–103], [15] as they differ from one another only by the transgene they encode.…”

“…The ablation of receptor CD46 and SLAM binding sites limits virus attachment and entry to cells expressing the receptor for the scFv or ligand linked to H. Retargeted MV-Edm derivatives retain their oncolytic activity against xenografts expressing target receptors [29–37]. A variety of scFv’s have been displayed on H against different receptors: EGFR (epidermal growth factor receptor) [29, 31]; EGFRvIII [29, 32]; HER2/neu (HER2: Human Epidermal Growth Factor Receptor 2) [38], CD20 [36, 37]; folate receptor alpha [33]; CD38 [29]; CEA (carcinoembryonic antigen) [39], prostate-specific membrane antigen (PSMA) [40] and an unidentified receptor over-expressed on multiple myeloma cells that can be targeted by Wue scFv [35]. Ligands linked to H have also successfully redirected entry, for example: amino-terminal fragment of urokinase plasminogen activator (uPA) targeting uPA receptor on breast tumors and tumor stroma [34]; snake venom peptide echistatin, targeting integrins αvβ3 and α5β1 expressed on vascular endothelium [41]; single-chain T-cell receptor (scTCR) targeting a specific peptide/MHC complex [42] and interleukin-13 targeting gliomas [30].…”