Application Route and Immune Status of the Host Determine Safety and Oncolytic Activity of Oncolytic Coxsackievirus B3 Variant PD-H.

Ahmet Hazini,Anja Geisler,Karin Klingel,Sophie Van Linthout,Ole Daberkow,Dennis Kobelt,Henry Fechner,Babette Dieringer,Markian Pryshliak,Jens Kurreck

doi:10.3390/v13101918

Abstract

The coxsackievirus B3 strain PD-0 has been proposed as a new oncolytic virus for the treatment of colorectal carcinoma. Here, we generated a cDNA clone of PD-0 and analyzed the virus PD-H, newly generated from this cDNA, in xenografted and syngenic models of colorectal cancer. Replication and cytotoxic assays revealed that PD-H replicated and lysed colorectal carcinoma cell lines in vitro as well as PD-0. Intratumoral injection of PD-H into subcutaneous DLD-1 tumors in nude mice resulted in strong inhibition of tumor growth and significantly prolonged the survival of the animals, but virus-induced systemic infection was observed in one of the six animals. In a syngenic mouse model of subcutaneously growing Colon-26 tumors, intratumoral administration of PD-H led to a significant reduction of tumor growth, the prolongation of animal survival, the prevention of tumor-induced cachexia, and the elevation of CD3+ and dendritic cells in the tumor microenvironment. No virus-induced side effects were observed. After intraperitoneal application, PD-H induced weak pancreatitis and myocarditis in immunocompetent mice. By equipping the virus with target sites of miR-375, which is specifically expressed in the pancreas, organ infections were prevented. Moreover, employment of this virus in a syngenic mouse model of CT-26 peritoneal carcinomatosis resulted in a significant reduction in tumor growth and an increase in animal survival. The results demonstrate that the immune status of the host, the route of virus application, and the engineering of the virus with target sites of suitable microRNAs are crucial for the use of PD-H as an oncolytic virus.

Highlights

Control digestion revealed that the plasmid clone pJet-coxsackievirus B3 (CVB3)-PD-H contained a band of the expected size of around 7.4 kb of the PD-0 genome (Figure 1A, right) and sequencing confirmed that the viral cDNA was inserted in the correct orientation (Figure 1B)
Compared to PD-0, the viral cDNA in pJet-CVB3PD-H had one nucleotide substitution at nucleotide position 881 leading to aa change in the VP4 [aa 47 [T→A] (Table S1)
Over the last few years, the oncolytic activity of different strains of the CVB3 has been demonstrated for the experimental treatment of cancer, among them, the CVB3 strain

Summary

Introduction

Oncolytic virotherapy is a new treatment for cancer. This therapy is induced by oncolytic viruses (OV) which infect and replicate in cancer cells without harming normal cells [1]. Tumor destruction induced by OV can be traced back to two fundamental mechanisms. Direct virus-induced tumor cell lysis which is a result of lytic virus infection of the tumor cells. This leads to a second mechanism, the release of pathogenassociated molecular patterns (PAMP), danger-associated molecular patterns (DAMP), cytokines, tumor-associated antigens (TAA) and neoantigens from the infected tumor cells, which induce the development of systemic innate and adaptive anticancer immune responses [2]

Methods

Results

Conclusion