Lentivirus vector driven by polybiquitin C promoter without woodchuck posttranscriptional regulatory element and central polypurine tract generates low level and short-lived reporter gene expression

Lentiviral delivery of novel fusion protein IL12/FasTI for cancer immune/gene therapy

Many of the cytokine-based cancer immunotherapies are hindered by the devastating side effects of systemic delivery of the cytokines. To address this problem, we previously described a novel approach to locally achieve high doses of interleukin-12 (IL-12) in tumors and demonstrated that bi-functional fusion protein mIL-12/FasTI expressed by stable clones of TC-1 cells efficiently suppressed tumor proliferation by activating natural killer (NK) cells and other cytolytic killer cells and sending apoptotic signals into tumor cells. In the present study, we employed a lentiviral vector-based gene delivery system to deliver this fusion construct directly into tumor cells. We show that lentiviral vector efficiently delivers the fusion constructs into Hela cells in vitro as assayed by RT-PCR and immunohistochemistry (IHC). We also confirm that fusion protein mIL-12/FasTI delivered by the viral vector significantly enhanced killer cell activation, increased caspase-3 activity and decreased tumor growth in vitro. This study offers a further step for fusion protein cancer therapy for cancer patients.

A simple and cost-saving phenotypic drug susceptibility testing of HIV-1

It is essential to monitor the occurrence of drug-resistant strains and to provide guidance for clinically adapted antiviral treatment of HIV/AIDS. In this study, an individual patient's HIV-1 pol gene encoding the full length of protease and part of the reverse transcriptase was packaged into a modified lentivirus carrying dual-reporters ZsGreen and luciferase. The optimal coefficient of correlation between drug concentration and luciferase activity was optimized. A clear-cut dose-dependent relationship between lentivirus production and luciferase activity was found in the phenotypic testing system. Fold changes (FC) to a wild-type control HIV-1 strain ratios were determined reflecting the phenotypic susceptibility of treatment-exposed patient's HIV-1 strains to 12 HIV-1 inhibitors including 6 nucleoside reverse-transcriptase inhibitors (NRTIs), 4 non-nucleoside reverse transcriptase inhibitors (NNRTIs) and 2 protease inhibitors (PIs). Phenotypic susceptibility calls from 8 HIV-1 infected patients were consistent with 80-90% genotypic evaluations, while phenotypic assessments rectified 10-20% genotypic resistance calls. By a half of replacement with ZsGreen reporter, the consumption of high cost Bright-Glo Luciferase Assay is reduced, making this assay cheaper when a large number of HIV-1 infected individuals are tested. The study provides a useful tool for interpreting meaningful genotypic mutations and guiding tailored antiviral treatment of HIV/AIDS in clinical practice.

Transgene expression from CpG-reduced lentiviral gene delivery vectors in vitro

Current viral gene delivery vectors for gene therapy are inefficient due to short-lived transgene expression attributed to the cytosine-phosphate-guanine (CpG) motifs in the transgene. Here we assessed the effects of CpG motif reduction in lentiviral (LV) gene delivery context on the level and duration of reporter gene expression in Chinese Hamster Ovary (CHO) cells, Human Immortalized Myelogenous Leukemia (K562) cells and hematopoietic stem cells (HSCs). The cells were transduced with LV carrying Zero-CpG green fluorescent protein (ZGFP) reporter gene, LV/CMV/ZGFP. The GFP expression was compared to its non CpG-depleted GFP reporter gene LV (LV/CMV/GFP) counterpart. The LV/CMV/ZGFP exhibited prolonged transgene expression in CHO cells and HSCs up to 10 days and 14 days, in the respective cells. This effect was not seen in the transduced K562 cells, which may be due to the DNA hypomethylation status of the cancer cell line. Transgene copy number analysis verified that the GFP expression was not from pseudo-transduction and the transgene remained in the genome of the cells throughout the period of the study. The modest positive effects from the LV/CMV/ZGFP suggest that the reduction of CpG in the LV construct was not substantial to generate higher and more prolonged transgene expression.