Dataset Information

Lentiviral vector with a radiation-inducible promoter, carrying the ING4 gene, mediates radiosensitization controlled by radiotherapy in cervical cancer cells.

ABSTRACT: The presence of hypoxia in solid tumors is considered one of the major factors that contribute to radiation resistance. The aim of the present study was to establish a therapeutic system, which can be controlled by radiation itself, to enhance radiosensitivity. For this purpose, a lentiviral gene therapy vector containing the human inhibitor of growth 4 (ING4) and its upstream promoter, human early growth response factor-1 (EGR1), which possesses the radiation-inducible characteristics to activate the transcription of its downstream genes, was constructed. Downstream fluorescence proteins were investigated to ensure that the EGR1 promoter was induced by irradiation. Furthermore, ING4 open reading frame (ORF) expression was detected by western blotting. The cell cycle was analyzed by fluorescence-activated cell sorting analysis 48 h after the cells were exposed to X-rays ranging between 0 and 8 Gy. In cells stably and transiently transfected with reporter plasmids, the EGR1-driver gene was sensitive to ionizing irradiation. Furthermore, irradiation-induced ING4 gene expression was observed. The enhanced ING4 expression increased the number of cells in the G₂/M phase and decreased the proportion of cells in the G₁/S phase. Therefore, ING4 expression inhibited cell proliferation and was associated with less colonies being formed. Furthermore, ING4 suppressed hypoxia-inducible factor 1? expression under hypoxic conditions and promoted cell apoptosis. Overall, these results revealed that combining the EGR1 promoter and ING4 ORF using a lentivirus system may be a promising therapeutic strategy with which to enhance radiosensitivity controlled by radiation. However, further studies using in vivo models are required to confirm these findings.

SUBMITTER: Ma T

PROVIDER: S-EPMC7716713 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Lentiviral vector with a radiation-inducible promoter, carrying the ING4 gene, mediates radiosensitization controlled by radiotherapy in cervical cancer cells.

Ma Tao T Guo Rui R Wang Xi X Shen Wen-Tong WT Zhu Min M Jin Ye-Ning YN Xu Hao-Ping HP

Oncology letters 20201125 1

The presence of hypoxia in solid tumors is considered one of the major factors that contribute to radiation resistance. The aim of the present study was to establish a therapeutic system, which can be controlled by radiation itself, to enhance radiosensitivity. For this purpose, a lentiviral gene therapy vector containing the human inhibitor of growth 4 (ING4) and its upstream promoter, human early growth response factor-1 (EGR1), which possesses the radiation-inducible characteristics to activa ...[more]

PMID: 33365078

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Project description:The importance of retinal glial cells in the maintenance of retinal health and in retinal degenerations has not been fully explored. Several groups have suggested that secretion of neurotrophic proteins from the retina's primary glial cell type, the Müller cell, holds promise for treating retinal degenerations. Tight regulation of transgene expression in Müller cells is likely to be critical to the efficacy of long-term neuroprotective therapies, due to the genetic heterogeneity and progressive nature of retinal disease. To this end, we developed a modified lentiviral (LV) transfer vector (pFTMGW) to accelerate the testing and evaluation of novel transcriptional regulatory elements. This vector facilitates identification and characterization of regulatory elements in terms of size, cell specificity and ability to control transgene expression levels.A synthetic multiple cloning site (MCS) which can accept up to five directionally cloned DNA regulatory elements was inserted immediately upstream of an enhanced green fluorescent protein (eGFP) reporter. A cytomegalovirus (CMV) promoter, required for tat-independent viral packaging, is located around 2 kb upstream of the eGFP reporter and is capable of directing transgene expression. A synthetic transcription blocker (TB) was inserted to insulate the MCS/eGFP from the CMV promoter. We evaluated eGFP expression from pFTMGW and control constructs using flow cytometry and quantitative reverse transcriptase polymerase chain reaction (RT-PCR). We also tested and compared the activity and cell specificity of a computationally identified promoter fragment from the rat vimentin gene (Vim409) in transfection and lentiviral infection experiments using fluorescence microscopy.Transfection data, quantitative RT-PCR, and flow cytometry show that around 85% of expression from the CMV promoter was blocked by the TB element, allowing direct evaluation of expression from the Vim409 candidate promoter cloned into the MCS. Lentiviruses generated from this construct containing the Vim409 promoter (without the TB element) drove robust eGFP expression in Müller cells in vitro and in vivo.The TB element efficiently prevented eGFP expression by the upstream CMV promoter and the novel MCS facilitated testing of an evolutionarily conserved regulatory element. Additional sites allow for combinatorial testing of additional promoter, enhancer, and/or repressor elements in various configurations. This modified LV transfer vector is an effective tool for expediting functional analysis of gene regulatory elements in Müller glia, and should prove useful for promoter analyses in other cell types and tissues.

Project description:BackgroundHIV-responsive expression vectors are all based on the HIV promoter, the long terminal repeat (LTR). While responsive to an early HIV protein, Tat, the LTR is also responsive to cellular activation states and to the local chromatin activity where the integration has occurred. This can result in high HIV-independent activity, and has restricted the use of LTR-based reporter vectors to cloned cells, where aberrantly high expressing (HIV-negative) cells can be eliminated. Enhancements in specificity would increase opportunities for expression vector use in detection of HIV as well as in experimental gene expression in HIV-infected cells.ResultsWe have constructed an expression vector that possesses, in addition to the Tat-responsive LTR, numerous HIV DNA sequences that include the Rev-response element and HIV splicing sites that are efficiently used in human cells. It also contains a reading frame that is removed by cellular splicing activity in the absence of HIV Rev. The vector was incorporated into a lentiviral reporter virus, permitting detection of replicating HIV in living cell populations. The activity of the vector was measured by expression of green fluorescence protein (GFP) reporter and by PCR of reporter transcript following HIV infection. The vector displayed full HIV dependency.ConclusionAs with the earlier developed Tat-dependent expression vectors, the Rev system described here is an exploitation of an evolved HIV process. The inclusion of Rev-dependency renders the LTR-based expression vector highly dependent on the presence of replicating HIV. The application of this vector as reported here, an HIV-dependent reporter virus, offers a novel alternative approach to existing methods, in situ PCR or HIV antigen staining, to identify HIV-positive cells. The vector permits examination of living cells, can express any gene for basic or clinical experimentation, and as a pseudo-typed lentivirus has access to most cell types and tissues.

Dataset Information

Lentiviral vector with a radiation-inducible promoter, carrying the ING4 gene, mediates radiosensitization controlled by radiotherapy in cervical cancer cells.

Publications

Lentiviral vector with a radiation-inducible promoter, carrying the ING4 gene, mediates radiosensitization controlled by radiotherapy in cervical cancer cells.

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