- 作者: Nan Du; Xuetao Pei; Jinming Zhou; Hui Zhao; Xiaosong Li; Yan Fu; Yixin Hao
- 作者服務機構: Department of Oncology First Affiliated hospital, Chinese PLA Postgraduate Medical School, Beijing, China
- 中文摘要: --
- 英文摘要:
Background :
Ionizing radiation (IR) activate the early growth response-1 (Egr-1) promoter by
production of radical oxygen intermediates (ROIs). Egr-EF, an expression vector
pCIneo containing Egr-1 promoter cloned upstream of the cDNA for Flt3 ligand, was
used to treat hematopoietic damage. 5-fluorouracil, a commonly used
chemotherapeutic agent, cause tumor cell death by producing DNA damage and
generating ROIs. We therefore hypothesized that clinically employed
chemotherapeutic agents that increase ROIs could also be employed to activate
Egr-EF in a chemoinducible gene therapy strategy. The goal of this study was to
explore the effect of Flt3 Ligand gene transcription regulated by fluorouracil-induced
Egr-1 promoter on hematopoietic recovery.
Methods :
Human Flt3 Ligand (FL) cDNA and enhanced green fluorescent protein (EGFP)
cDNA were linked together with IRES and inserted into the expression vector
pCI-neo under control of the Egr-1 promoter (Egr-EF). The vector was transfected
into the HFCL human bone marrow stromal cell line, and these cells were exposed to
5-FU, a chemotherapeutic drug. Expression of FL by HFCL/EF cells after 5-FU
treatment was determined with ELISA, western blot and RT-PCR assays. In addition,
the effect of FL from HFCL/EF cell culture supernatants on growth of CD34+ cells
from cord blood was also studied. HFCL/EF cells were injected into CB-17 combined
immunodeficient (SCID) mice with B16 melanoma. 5-FU was given three days after injection of the HFCL/EF cells. In the recipient mice, white blood cell levels in
peripheral blood and expression of EGFP and FL in human stromal cells were
measured. Tumor volumes in tumor-bearing mice were also measured.
Results :
5-FU treatment increased EGFP levels and secreted FL levels in HFCL/EF cells.
Supernatants from HFCL/EF cell cultures treated with 5-FU increased CD34+ cell
growth significantly. HFCL/EF exhibited an increase in the number of white blood
cells after chemotherapy.
Conclusions :
The data presented here support the use of transcriptional control mediated by
chemoinducible gene therapy to reduce hematopoietic injury associated with 5-FU. - 中文關鍵字: --
- 英文關鍵字: --