Transcriptional and Translational Dual-regulated Oncolytic Herpes Simplex Virus Type 1 for Targeting Prostate Tumors

Abstract

The aim of this project was to demonstrate that an oncolytic herpes simplex virus type 1 (HSV-1) can replicate in a tissue- and tumor-specific fashion through both transcriptional (prostate-specific promoter, ARR(2)PB) and translational (5'-untranslated regions (5'UTRs) of rFGF-2) regulation of an essential viral gene, ICP27. We generated two recombinant viruses, ARR(2)PB-ICP27 (A27) and ARR(2)PB-5'UTR-ICP27 (AU27) and tested their efficacy and toxicity both in vitro and in vivo. The ARR(2)PB promoter caused overexpression of ICP27 gene in the presence of activated androgen receptors (ARs) and increased viral replication in prostate cells. However, this transcriptional upregulation was effectively constrained by the 5'UTR-mediated translational regulation. Mice bearing human prostate LNCaP tumors, treated with a single intravenous injection of 5 x 10(7) plaque-forming units (pfu) of AU27 virus exhibited a >85% reduction in tumor size at day 28 after viral injection. Although active viral replication was readily evident in the tumors, no viral DNA was detectable in normal organs as measured by real-time PCR analyses. In conclusion, a transcriptional and translational dual-regulated (TTDR) viral essential gene expression can increase both viral lytic activity and tumor specificity, and this provides a basis for the development of a novel tumor-specific oncolytic virus for systemic treatment of locally advanced and metastatic prostate cancers.

Biomarkers to identify and isolate senescent cells

“…was required for the function of the virus (Barker et al, 2003;Larson et al, 2015;Lee et al, 2010;Singh et al, 2012). For example, one study constructed an adenovirus in which gene E1a was under the control of the hTERT (human telomerase reverse transcriptase) promoter while the viral gene E1b was under the control of the HRE (hypoxia response element) promoter .…”

Fibroblast growth factor and ornithine decarboxylase 5′UTRs enable preferential expression in human prostate cancer cells and in prostate tumors of PTEN−/− transgenic mice

“…8,24 In this regard, our laboratory has previously demonstrated that eIF4E is a good discriminatory factor between normal and cancer cells as eIF4E levels are substantially elevated in the latter. 4,15,20 eIF4E is the rate-limiting subunit of the eIF4F complex, which is comprised of eIF4E, the cap binding protein; eIF4A, an ATPase and RNA helicase; and eIF4G, a scaffolding protein. eIF4E is critical for initiating the process of translation by binding to the 5 0 -cap 7-methylguanosine (m7G) present on all nuclear transcribed mRNAs, 25 and together with the eIF4F complex, unwinds the excess secondary structures within the 5 0 UTR to facilitate the loading of the 40S ribosomal subunit to the mRNA.…”

“…Comparison of eIF4E levels in prostate cancer cell lines to those in nonmalignant prostate cells (Figure 1) revealed that eIF4E levels were higher in cancer cell lines, in agreement with what has been previously shown. 20 To establish that our lentiviral plasmids containing complex 5 0 UTRs are translated at a lower rate in nonmalignant cells, lentiviral transfer plasmids (FUGW, FU-ODC 149 -GW, FU-ODC 274 -GW and FU-FGF2-GW) were transfected into nonmalignant prostate cells. Expression of each plasmid was estimated through GFP protein expression and normalized to control FUGW plasmid.…”

Oncoselectivity in Oncolytic Viruses against Colorectal Cancer

“…A recent example provided by Lee and colleagues [105] not only demonstrates successful translational regulation in a RCOV but also shows how regulatory regimes can be designed which interact synergistically and produce greater oncolytic selectivity than would be possible with just a single regulatory constraint. The HSV-1 gene ICP27 is essential for viral replication [106].…”

“…The HSV-1 gene ICP27 is essential for viral replication [106]. Lee and colleagues [105] have engineered a recombinant HSV-1 in which the ICP27 gene was placed under both transcriptional and translational control. A modified promoter (designated ARR2PB) for the prostate-specific protein probasin [107] was used to drive expression of ICP27 in the recombinant HSV-1.…”