Redesigned<i>Escherichia coli</i>cytosine deaminase: a new facet of suicide gene therapy

Raza, Asif; Kohila, V.; Ghosh, Siddhartha Sankar

doi:10.1002/jgm.2831

Cited by 15 publications

(19 citation statements)

References 20 publications

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“…Stable transfection of Cx43 was performed as described previously in ref. 20 . The overexpression of Cx43 was assessed by semi-quantitative PCR and quantitative real-time PCR (qPCR; primer sequences provided in supplementary info).…”

Section: Methodsmentioning

confidence: 99%

Connexin-43 enhances tumor suppressing activity of artesunate via gap junction-dependent as well as independent pathways in human breast cancer cells

Raza

Ghoshal

Chockalingam

et al. 2017

Sci Rep

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The gap junction (GJ) protein connexin-43 (Cx43) is considered as a tumour suppressor protein for its role in reversing the phenotype of the cancer cells. In this study, we exploited the antitumor property of Cx43 in conjunction with the artesunate (ART), a plant-based active anti-malarial compound. The reactive oxygen species (ROS) generated by ART resulted in DNA damage, which in turn led to DNA damage response by activation of DNA damage repair proteins. GJ deficient MCF-7 cells transfected with Cx43 gene showed an increased sensitivity towards dose-dependent ART treatment and required a significantly lower dose of ART to attain its IC50, as compared to parental cells. This would ultimately result in reduced dose-dependent side effects of ART. The Co-culture experiments involving GJ intercellular communication (GJIC) deficient and GJIC enabled cells, established the transfer of ROS to the neighbouring cancer cells not exposed to ART. The ROS accumulated in the ART-treated cells induced the oxidative damage in neighbouring cells, leading to bystander cell death and inhibition of bystander cell proliferation. Thus, our study revealed that expression of Cx43 helped in reducing the dose-dependent cytotoxicity of ART as well as enhanced the bystander apoptosis of the neighbouring cells.

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Section: Methodsmentioning

confidence: 99%

Connexin-43 enhances tumor suppressing activity of artesunate via gap junction-dependent as well as independent pathways in human breast cancer cells

Raza

Ghoshal

Chockalingam

et al. 2017

Sci Rep

Self Cite

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“…Although these approaches have looked promising in some pre-clinical models, the low efficiency of bacterial CD to convert 5-FC into 5-FU limited the overall therapeutic response. Recently, Ghosh et al have mutated CD to increase its affinity to 5-FC and reduce the amount of 5-FC required as prodrug [42–44]. …”

Section: Evolution Of Safety Switchesmentioning

confidence: 99%

“…One set of switches targets surface molecules (CD20, EGFR) [32–37], while a second uses a transgenic enzyme to activate a cytotoxic pro-drug (HSV-thymidine kinase gene + GCV or cytosine deaminase + 5FC) [38–44]. Engineering therapeutic T cells with a peptide-specific antibody-based switch is another strategy to control the activation and expansion of these cells [45].…”

Section: Introductionmentioning

confidence: 99%

Improving the safety of T-Cell therapies using an inducible caspase-9 gene

Zhou

Brenner

2016

Experimental Hematology

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Adoptive transfer of T cells can be an effective anti-cancer treatment. However, uncontrolled or unpredictable immediate or persistent toxicities are a source of concern. The ability to conditionally eliminate aberrant cells in vivo therefore is becoming a critical step for the successful translation of this approach to the clinic. We review the evolution of safety systems, focusing on a suicide switch that can be expressed stably and efficiently in human T cells without impairing phenotype, function or antigen specificity. This system is based on the fusion of human caspase 9 to a modified human FK-binding protein, allowing conditional dimerization in the presence of an otherwise bioinert small molecule drug. When exposed to the synthetic dimerizing drug, the inducible caspase 9 (iC9) becomes activated and leads to the rapid apoptosis of cells expressing this construct. We have demonstrated the clinical feasibility and efficacy of this approach after haploidentical hematopoietic stem cell transplant (haplo-HSCT). Here we review the benefits and limitations of the approach.

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“…Also, cytosine deaminase has a poor binding affinity towards 5-FC compared to the natural substrate cytosine, unless a mutated form of the enzyme is used. 22 (iii) Selective elimination of PSC by an oleate synthesis inhibitor discovered in a high-throughput screen 23 ; however these compounds have so far been given only pretransplantation and most likely act only on cells in the pluripotency stage and not on proliferating neuroprecursors.(iv) A recent study has suggested that irradiation of transplanted cells could be an alternative to a suicide gene technology to achieve elimination of proliferating cells. Given the potential toxicity of CNS irradiation, we do not think that this approach is the most promising for future application in patients.…”

Section: Discussionmentioning

confidence: 99%

“…Also, cytosine deaminase has a poor binding affinity towards 5-FC compared to the natural substrate cytosine, unless a mutated form of the enzyme is used. 22 …”

Section: Discussionmentioning

confidence: 99%

Elimination of proliferating cells from CNS grafts using a Ki67 promoter-driven thymidine kinase

Tieng

Cherpin

Gutzwiller

et al. 2016

Molecular Therapy - Methods & Clinical Development

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Pluripotent stem cell (PSC)-based cell therapy is an attractive concept for neurodegenerative diseases, but can lead to tumor formation. This is particularly relevant as proliferating neural precursors rather than postmitotic mature neurons need to be transplanted. Thus, safety mechanisms to eliminate proliferating cells are needed. Here, we propose a suicide gene approach, based on cell cycle-dependent promoter Ki67-driven expression of herpes simplex virus thymidine kinase (HSV-TK). We generated a PSC line expressing this construct and induced neural differentiation. In vitro, proliferating PSC and early neural precursor cells (NPC) were killed by exposure to ganciclovir. In vivo, transplantation of PSC led to tumor formation, which was prevented by early ganciclovir treatment. Transplanted NPC did not lead to tumor formation and their survival and neural maturation were not affected by ganciclovir. In conclusion, the cell cycle promoter-driven suicide gene approach described in this study allows killing of proliferating undifferentiated precursor cells without expression of the suicide gene in mature neurons. This approach could also be of use for other stem cell-based therapies where the final target consists of postmitotic cells.

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RedesignedEscherichia colicytosine deaminase: a new facet of suicide gene therapy

Abstract: We report a novel bacterial CD mutant that provided a superior alternate to the wtCD suicide gene. The F186W mutant required a much lower dose of 5-FC to reach its IC50 , thus minimizing the systemic side effects of large doses of 5-FC as required for wtCD.

Cited by 15 publications

References 20 publications

Connexin-43 enhances tumor suppressing activity of artesunate via gap junction-dependent as well as independent pathways in human breast cancer cells

Connexin-43 enhances tumor suppressing activity of artesunate via gap junction-dependent as well as independent pathways in human breast cancer cells

Improving the safety of T-Cell therapies using an inducible caspase-9 gene

Elimination of proliferating cells from CNS grafts using a Ki67 promoter-driven thymidine kinase

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