Highly efficient lentiviral transduction of phenotypically and genotypically characterized endothelial progenitor cells from adult peripheral blood. Blood Coagul Fibrinolysis. 2010;21:464-473. [PMID: 20595824 DOI: 10.1097/MBC.0b013e328339cc1c]

Labeling and qualification of endothelial progenitor cells for tracking in tissue engineering: An in vitro study

PURPOSE

In order to track location and distribution of endothelial cells (ECs) within scaffolds in vitro, we chose lentiPGK-TdTomato transduction of human endothelial progenitor cells (EPCs) isolated and differentiated from cord blood. Because transduction could have a functional impact on cell behavior, we checked different parameters for qualification of labeled- EPCs as well as their use for potential applications in the context of vascular and bone tissue engineering.

METHODS

After isolation and expansion, EPCs were classically characterized then transduced with the lentiviral vector containing the TdTomato protein gene under the control of the phosphoglycerate kinase (PGK) promoter. Conventional karyotyping, differentiation capacity, viability, proliferation assays were performed with labeled and unlabeled EPCs. Scaffolds and co-cultures were explored with labeled EPCs, in static or shear stress conditions.

RESULTS

Our results show that cell labeling did not affect cell adhesion nor induce cell death. Cell labeling did not induce more chromosomal aberrations. Phenotypical characterization was not affected. In the context of tissue engineering applications, labeled EPCs maintained their ability to line 2D or 3D scaffolds, withstand physiological arterial shear stress, and form tubular networks in co-cultures with human osteoblast progenitor cells.

CONCLUSIONS

It is possible to label human EPCs with TdTomato without affecting their behavior by the transduction procedure. This creates an important tool for numerous applications. Our results provide a qualification of labeled EPCs in comparison with unlabeled ones for vascular and bone tissue engineering.

A systematic approach to the establishment and characterization of endothelial progenitor cells for gene therapy

It has been recently demonstrated that endothelial progenitor cells (EPCs) have increasing potential for gene therapy or regenerative cell therapy for cardiovascular diseases and cancer. However, current therapies involving EPCs are inefficient because of the very low level of EPCs in the available sources, for example, in blood. One solution is to derive in vitro an expanded population of EPCs from circulation. In addition, EPCs like other progenitor cells have an intrinsic predisposition of differentiating into mature cell types, for example, mature endothelial cells; therefore, establishing a sufficient amount of EPCs alongside maintaining the EPC characteristic phenotype during genetic modification and long-term culture presents a significant challenge to the field of gene and cell therapies. In this study, we have systematically investigated EPCs from different sources and used multiple parameters, including cell surface markers and a tubule formation assay to identify factors that influence the establishment, characteristics, and vector transduction capability of EPCs. Our results show the considerable promise, as well as certain limitations in the establishment and manipulation of genetically modified EPCs for gene therapy. While obtaining high transduction efficiency and robust in vitro tubule formation of EPCs using lentiviral vectors, we also observed that lentiviral vector transduction significantly altered EPC phenotype as demonstrated by an increased percentage of CD34(+) progenitor cells and increased expression of adhesion molecule CD144 (VE-cadherin). Taking account of the increased expression of CD144 reported in cancer patients, the altered expression of EPC-related markers, for example, VE-cadherin and the enrichment of CD34(+) cells, after vector transduction indicates the importance of extensive characterization and vigorous safety control of genetically modified EPCs before they are accepted for clinical use.

Intravenous administration of endothelial progenitor cells transfected with the TRAIL gene inhibits the growth of tumors derived from H22 cells in nude mice

AIM: To investigate the influence of intravenous administration of endothelial progenitor cells (EPCs) transfected with the TRAIL gene on the growth of tumors derived from subcutaneously inoculated H22 cells in nude mice to provide a theoretical basis for the treatment of liver cancer.

METHODS: The TRAIL gene was amplified by PCR, cloned into the pcDNA3.1 vector, and transfected into EPCs. The expression of TRAIL protein was detected by Western blot. Mice were inoculated subcutaneously with H22 cells to induce tumor formation. Tumor-bearing mice were randomly divided into three groups and injected via the tail vein with EPCs transfected with the recombinant adenoviral vector carrying the TRAIL gene, the empty vector, and normal saline, respectively.

RESULTS: Restriction enzyme digestion and DNA sequencing analyses indicate that the recombinant plasmid was constructed successfully. TRAIL expression was detected in EPCs transfected with the recombinant adenoviral vector by Western blot. The rate of reduced tumor growth was 47.77% in mice administered with EPCs carrying the TRAIL gene. Tumor volume and weight in the experimental group (0.791 cm3 ± 0.119 cm3, 0.29 g ± 0.04 g) were significantly lower than those in the two control groups (all P < 0.05).

CONCLUSION: The recombinant plasmid carrying the TRAIL gene has been successfully constructed. Intravenous administration of endothelial progenitor cells transfected with the TRAIL gene inhibits the growth of tumors derived from H22 cells in nude mice.