MicroRNA Regulation of Oncolytic Herpes Simplex Virus-1 for Selective Killing of Prostate Cancer Cells

Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
Clinical Cancer Research (Impact Factor: 8.19). 09/2009; 15(16):5126-35. DOI: 10.1158/1078-0432.CCR-09-0051
Source: PubMed

ABSTRACT Advanced castration-resistant prostate cancer, for which there are few treatment options, remains one of the leading causes of cancer death. MicroRNAs (miRNA) have provided a new opportunity for more stringent regulation of tumor-specific viral replication. The purpose of this study was to provide a proof-of-principle that miRNA-regulated oncolytic herpes simplex virus-1 (HSV-1) virus can selectively target cancer cells with reduced toxicity to normal tissues.
We incorporated multiple copies of miRNA complementary target sequences (for miR-143 or miR-145) into the 3'-untranslated region (3'-UTR) of an HSV-1 essential viral gene, ICP4, to create CMV-ICP4-143T and CMV-ICP4-145T amplicon viruses and tested their targeting specificity and efficacy both in vitro and in vivo.
Although miR-143 and miR-145 are highly expressed in normal tissues, they are significantly down-regulated in prostate cancer cells. We further showed that miR-143 and miR-145 inhibited the expression of the ICP4 gene at the translational level by targeting the corresponding 3'-UTR in a dose-dependent manner. This enabled selective viral replication in prostate cancer cells. When mice bearing LNCaP human prostate tumors were treated with these miRNA-regulated oncolytic viruses, a >80% reduction in tumor volume was observed, with significantly attenuated virulence to normal tissues in comparison with control amplicon viruses not carrying these 3'-UTR sequences.
Our study is the first to show that inclusion of specific miRNA target sequences into the 3'-UTR of an essential HSV-1 gene is a viable strategy for restricting viral replication and oncolysis to cancer cells while sparing normal tissues.

Download full-text


Available from: William WeiGuo Jia, Mar 29, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: HSV-1 infection in the cornea could lead to blindness. The infected cell polypeptide 4 (ICP4) of herpes simplex virus 1 (HSV-1) is a regulator of viral transcription that is required for productive infection. It has been previously demonstrated that miR-H6 encoded from HSV-1 genome targets ICP4 to help maintain latency. In this study, synthesized miR-H6 mimics were transfected into HSV-1-infected human cornea epithelial (HCE) cells. The inhibition of HSV-1 replication and viral ICP4 expression in miR-H6-transfected HCE was confirmed by plaque assay, immunofluorescence, and Western blot. Compared to nontransfection or mock, miR-H6 produced a low-titer HSV-1 and weak ICP4 expression. In addition, miR-H6 can decrease the interleukin 6 released into the medium, which was determined by ELISA. Taken together, the data suggests that miR-H6 targeting of ICP4 inhibits HSV-1 productive infection and decreases interleukin 6 production in HCE, and this may provide an approach to prevent HSV-1 lytic infection and inhibit corneal inflammation.
    Clinical and Developmental Immunology 04/2012; 2012:192791. DOI:10.1155/2012/192791 · 2.93 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Engineering viruses by inserting microRNA (miRNA) recognition elements (MREs) into the 3'-untranslated region (3'-UTR) of viral RNA can efficiently restrict viral tissue tropism. We used the mosquito-borne Japanese encephalitis virus (JEV) to investigate whether endogenous neuron-specific microRNA-124 (miR-124) could be used to restrict viral neurotropism and, consequently, diminish the neurovirulence of JEV in mice. To recover a neuron-restricted JEV, we inserted 2 copies of a perfectly matched MRE specific to miR-124 into the 3'-UTR to create infectious JEV recombinant RP-124PT (rRP-124PT). The effect of rRP-124PT was attenuated in infected mice as compared with MRE mutant and parental strains, both of which were lethal to challenged mice. Immunization with rRP-124PT appeared to elicit full protective immunity against subsequent JEV lethal challenge. We found neurons of the central nervous system critical targets for infection by JEV, which directly causes lethal encephalitis. The silencing of JEV rRP-124PT in mice by miR-124 illustrates that endogenous miRNA can readily recognize and interact with the 3'-UTR of naturally occurring genomic/mRNAs lacking a polyadenylated tail. Inserting MREs into viral RNA may facilitate further study of flaviviral pathogenesis involving tissue tropism and suggest an additional layer of biosafety for the rational design of safe flavivirus vaccines.
    Vaccine 10/2011; 31(49). DOI:10.1016/j.vaccine.2011.09.102 · 3.49 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: MicroRNAs (miRNA) are noncoding RNAs that post-transcriptionally regulate gene expression. Their altered expression and function have been observed in most urologic cancers. MiRNAs represent potential disease biomarkers and novel therapeutic targets. To review and evaluate the evidence implicating miRNAs in the pathogenesis of prostate cancer (PCa), bladder cancer (BCa), and renal cancer. A systematic review was performed using PubMed and Embase to search for reports using strings for microRNA, non-coding RNA, cancer, prostate, bladder, and renal cancer. Identified manuscripts were retrieved and references searched. Selected studies were required to concentrate on the role of miRNA in these urologic cancers. We reviewed articles that focus on this topic. More than 40 miRNAs have been implicated in urologic cancer and many target common carcinogenic pathways. In particular, apoptosis avoidance, cell proliferation, epithelial-to-mesenchymal transition, angiogenic signalling, and the generation of androgen independence are targeted or facilitated by more than one miRNA. Little work has been done to evaluate the translational applications for this knowledge to date. Novel therapeutic strategies have been developed and are under investigation to selectively modulate miRNAs; such work would potentially enable personalised tumour therapy. MiRNAs appear to be important modulators of urologic cancer. Their expression is frequently altered in these tumours, and many are functionally implicated in their pathogenesis. They require evaluation to determine the translational role and therapeutic potential for this knowledge.
    European Urology 02/2011; 59(5):671-81. DOI:10.1016/j.eururo.2011.01.044 · 12.48 Impact Factor