Xichen Zhang

University of Pittsburgh, Pittsburgh, Pennsylvania, United States

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Publications (34)69.96 Total impact

  • Experimental hematology. 08/2014; 42(8S):S32.
  • Experimental hematology. 08/2014; 42(8S):S32.
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    ABSTRACT: The altered DNA damage response pathway in patients with Fanconi anemia (FA) may increase the toxicity of clinical radiotherapy. We quantitated oral cavity mucositis in irradiated Fanconi anemia Fancd2(-/-) mice, comparing this to Fancd2(+/-) and Fancd2(+/+) mice, and we measured distant bone marrow suppression and quantitated the effect of the intraoral radioprotector GS-nitroxide, JP4-039 in F15 emulsion. We found that FA mice were more susceptible to radiation injury and that protection from radiation injury by JP4-039/F15 was observed at all radiation doses. Adult 10-12-week-old mice, of FVB/N background Fancd2(-/-), Fancd2(+/-) and Fancd2(+/+) were head and neck irradiated with 24, 26, 28 or 30 Gy (large fraction sizes typical of stereotactic radiosurgery treatments) and subgroups received intraoral JP4-039 (0.4 mg/mouse in 100 μL F15 liposome emulsion) preirradiation. On day 2 or 5 postirradiation, mice were sacrificed, tongue tissue and femur marrow were excised for quantitation of radiation-induced stress response, inflammatory and antioxidant gene transcripts, histopathology and assay for femur marrow colony-forming hematopoietic progenitor cells. Fancd2(-/-) mice had a significantly higher percentage of oral mucosal ulceration at day 5 after 26 Gy irradiation (59.4 ± 8.2%) compared to control Fancd2(+/+) mice (21.7 ± 2.9%, P = 0.0063). After 24 Gy irradiation, Fancd2(-/-) mice had a higher oral cavity percentage of tongue ulceration compared to Fancd2(+/+) mice irradiated with higher doses of 26 Gy (P = 0.0123). Baseline and postirradiation oral cavity gene transcripts were altered in Fancd2(-/-) mice compared to Fancd2(+/+) controls. Fancd2(-/-) mice had decreased baseline femur marrow CFU-GM, BFUe and CFU-GEMM, which further decreased after 24 or 26 Gy head and neck irradiation. These changes were not seen in head- and neck-irradiated Fancd2(+/+) mice. In radiosensitive Fancd2(-/-) mice, biomarkers of both local oral cavity and distant marrow radiation toxicity were ameliorated by intraoral JP4-039/F15. We propose that Fancd2(-/-) mice are a valuable radiosensitive animal model system, which can be used to evaluate potential radioprotective agents.
    Radiation research. 06/2014;
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    ABSTRACT: FancD2 plays a central role in the human Fanconi anemia DNA damage response (DDR) pathway. Fancd2(-/-) mice exhibit many features of human Fanconi anemia including cellular DNA repair defects. Whether the DNA repair defect in Fancd2(-/-) mice results in radiologic changes in all cell lineages is unknown. We measured stress of hematopoiesis in long-term marrow cultures and radiosensitivity in clonogenic survival curves, as well as comet tail intensity, total antioxidant stores and radiation-induced gene expression in hematopoietic progenitor compared to bone marrow stromal cell lines. We further evaluated radioprotection by a mitochondrial-targeted antioxidant GS-nitroxide, JP4-039. Hematopoiesis longevity in Fancd2(-/-) mouse long-term marrow cultures was diminished and bone marrow stromal cell lines were radiosensitive compared to Fancd2(+/+) stromal cells (Fancd2(-/-) D0 = 1.4 ± 0.1 Gy, ñ = 5.0 ± 0.6 vs. Fancd2(+/+) D0 = 1.6 ± 0.1 Gy, ñ = 6.7 ± 1.6), P = 0.0124 for D0 and P = 0.0023 for ñ, respectively). In contrast, Fancd2(-/-) IL-3-dependent hematopoietic progenitor cells were radioresistant (D0 = 1.71 ± 0.04 Gy and ñ = 5.07 ± 0.52) compared to Fancd2(+/+) (D0 = 1.39 ± 0.09 Gy and ñ = 2.31 ± 0.85, P = 0.001 for D0). CFU-GM from freshly explanted Fancd2(-/-) marrow was also radioresistant. Consistent with radiosensitivity, irradiated Fancd2(-/-) stromal cells had higher DNA damage by comet tail intensity assay compared to Fancd2(+/+) cells (P < 0.0001), slower DNA damage recovery, lower baseline total antioxidant capacity, enhanced radiation-induced depletion of antioxidants, and increased CDKN1A-p21 gene transcripts and protein. Consistent with radioresistance, Fancd2(-/-) IL-3-dependent hematopoietic cells had higher baseline and post irradiation total antioxidant capacity. While, there was no detectable alteration of radiation-induced cell cycle arrest with Fancd2(-/-) stromal cells, hematopoietic progenitor cells showed reduced G2/M cell cycle arrest. The absence of the mouse Fancd2 gene product confers radiosensitivity to bone marrow stromal but not hematopoietic progenitor cells.
    Radiation Research 01/2014; · 2.70 Impact Factor
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    ABSTRACT: A water-soluble ionizing radiation mitigator would have considerable advantages for the management of acute and chronic effects of ionizing radiation. We report that a novel oxetanyl sulfoxide (MMS350) is effective both as a protector and a mitigator of clonal mouse bone marrow stromal cell lines in vitro, and is an effective in vivo mitigator when administered 24 h after 9.5 Gy (LD100/30) total-body irradiation of C57BL/6NHsd mice, significantly improving survival (P = 0.0097). Furthermore, MMS350 (400 μM) added weekly to drinking water after 20 Gy thoracic irradiation significantly decreased: expression of pulmonary inflammatory and profibrotic gene transcripts and proteins; migration into the lungs of bone marrow origin luciferase+/GFP+ (luc+/GFP+) fibroblast progenitors (in both luc+ marrow chimeric and luc+ stromal cell line injected mouse models) and decreased radiation-induced pulmonary fibrosis (P < 0.0001). This nontoxic and orally administered small molecule may be an effective therapeutic in clinical radiotherapy and as a counter measure against the acute and chronic effects of ionizing radiation.
    Radiation Research 10/2013; · 2.70 Impact Factor
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    ABSTRACT: Mitochondrial targeted manganese superoxide dismutase is a major antioxidant enzyme, the levels of which modulate the response of cells, tissues and organs to ionizing irradiation. We developed a Tet-regulated MnSOD mouse (MnSOD(tet)) to examine the detailed relationship between cellular MnSOD concentration and radioresistance and carried out in vitro studies using bone marrow culture derived stromal cell lines (mesenchymal stem cells). Homozygous MnSOD(tet/tet) cells had low levels of MnSOD, reduced viability and proliferation, increased radiosensitivity, elevated overall antioxidant stores, and defects in cell proliferation and DNA strand-break repair. Doxycycline (doxy) treatment of MnSOD(tet/tet) cells increased MnSOD levels and radioresistance from ñ of 2.79 ± 1.04 to 8.69 ± 1.09 (P = 0.0060) and normalized other biologic parameters. In contrast, MnSOD(tet/tet) cells showed minimal difference in baseline and radiation induced mRNA and protein levels of TGF-β, Nrf2 and NF-κB and radiation induced cell cycle arrest was not dependent upon MnSOD level. These novel MnSOD(tet/tet) mouse derived cells should be valuable for elucidating several parameters of the oxidative stress response to ionizing radiation.
    Radiation Research 07/2013; · 2.70 Impact Factor
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    ABSTRACT: Carbamazepine, a sodium channel blocker and pro-autophagy agent used in the treatment of epilepsy and trigeminal neuralgia, is also an ionizing radiation mitigator and protector. We measured the effect of carbamazepine, compared to other pro-autophagy drugs (i.e. lithium and valproic acid), on irradiation of autophagy incompetent (Atg5(-/-)) and competent (Atg5(+/+)) mouse embryonic fibroblasts, p53(-/-) and p53(+/+) bone marrow stromal cells, and human IB3, KM101, HeLa, and umbilical cord blood cell and in total body-irradiated or orthotopic tumor-bearing mice. Carbamazepine, but not other pro-autophagy drugs, was a radiation protector and mitigator for mouse cell lines, independent of apoptosis, autophagy, p53, antioxidant store depletion, and class I phosphatidylinositol 3-kinase, but was ineffective with human cells. Carbamazepine was effective when delivered 24 hours before or 12 hours after total body irradiation of C57BL/6HNsd mice and did not protect orthotopic Lewis lung tumors. Carbamazepine is a murine radiation protector and mitigator.
    In vivo (Athens, Greece) 05/2012; 26(3):341-54. · 1.15 Impact Factor
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    ABSTRACT: The effect of lung irradiation on reduction of lung stem cells and repopulation with bone marrow-derived cells was measured. Expression of green fluorescent protein positive cells (GFP(+)) in the lungs of thoracic irradiated FVB/NHsd mice (Harlan Sprague Dawley, Indianapolis, IN, USA) was determined. This was compared to the repopulation of bone marrow-derived cells found in the lungs from naphthalene treated male FVB/NHsd mice and gangciclovir (GCV) treated FeVBN GFP(+) male marrow chimeric HSV-TK-CCSP. The level of mRNA for lung stem cell markers clara cell (CCSP), epithelium 1 (FOXJ1) and surfactant protein C (SP-C), and sorted single cells positive for marrow origin epithelial cells (GFP(+)CD45(-)) was measured. The expression of pulmonary stem cells as determined by PCR was reduced most by GCV, then naphthalene, and least by thoracic irradiation. Irradiation, like GCV, reduced mRNA expression of CCSP, CYP2F2, and FOXJ1, while naphthalene reduced that of CCSP and CYP2F2. Ultrastructural analysis showed GFP(+) pulmonary cells of bone marrow origin, with the highest frequency being found in GCV-treated groups. Bone marrow progenitor cells may not participate in the repopulation of the lung following irradiation.
    In vivo (Athens, Greece) 01/2012; 26(1):9-18. · 1.15 Impact Factor
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    ABSTRACT: Fanconi anemia (FA) is an inherited disorder characterized by defective DNA repair and cellular sensitivity to DNA crosslinking agents. Clinically, FA is associated with high risk for marrow failure, leukemia and head and neck squamous cell carcinoma (HNSCC). Radiosensitivity in FA patients compromises the use of total-body irradiation for hematopoietic stem cell transplantation and radiation therapy for HNSCC. A radioprotector for the surrounding tissue would therefore be very valuable during radiotherapy for HNSCC. Clonogenic radiation survival curves were determined for pre- or postirradiation treatment with the parent nitroxide Tempol or JP4-039 in cells of four FA patient-derived cell lines and two transgene-corrected subclonal lines. FancG(-/-) (PD326) and FancD2(-/-) (PD20F) patient lines were more sensitive to the DNA crosslinking agent mitomycin C (MMC) than their transgene-restored subclonal cell lines (both P < 0.0001). FancD2(-/-) cells were more radiosensitive than the transgene restored subclonal cell line (ñ = 2.0 ± 0.7 and 4.7 ± 2.2, respectively, P = 0.03). In contrast, FancG(-/-) cells were radioresistant relative to the transgene-restored subclonal cell line (ñ = 9.4 ± 1.5 and 2.2 ± 05, respectively, P = 0.001). DNA strand breaks measured by the comet assay correlated with radiosensitivity. Cell lines from a Fanc-C and Fanc-A patients showed radiosensitivity similar to that of Fanc-D2(-/-) cells. A fluorophore-tagged JP4-039 (BODIPY-FL) analog targeted the mitochondria of the cell lines. Preirradiation or postirradiation treatment with JP4-039 at a lower concentration than Tempol significantly increased the radioresistance and stabilized the antioxidant stores of all cell lines. Tempol increased the toxicity of MMC in FancD2(-/-) cells. These data provide support for the potential clinical use of JP4-039 for normal tissue radioprotection during chemoradiotherapy in FA patients.
    Radiation Research 09/2011; 176(5):603-12. · 2.70 Impact Factor
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    ABSTRACT: To determine whether Carbamazepine (CBZ) is a radiation protector and/or mitigator. Murine hematopoietic progenitor 32D cl 3 cells were incubated in 1, 10, or 100 μM CBZ 1 h before or immediately after 0-8 Gy irradiation and assayed for clonogenic survival. Autophagy was assayed by immunoblot for microtubule-associated protein light chain 3 (LC3). In vivo radioprotection and mitigation were determined with C57BL/6NTac mice. CBZ treatment at 1, 10 or 100 μM for 1 h prior to irradiation increased radioresistance (the dose for 37% survival or D(0)) from control 1.5 ± 0.1 Gy to 2.1 ± 0.2 Gy (P = 0.012), 2.3 ± 0.1 Gy (P = 0.010), and 3.6 ± 0.7 Gy (P = 0.003), respectively; after irradiation increased the extrapolation number (ñ) from 1.5 ± 0.3 to 10.1 ± 4.2 (P = 0.011), 5.5 ± 1.7 (P = 0.019), and 3.6 ± 0.8 (P = 0.014), respectively, and increased autophagy. CBZ treated mice 10 min or 24 h before or 10 min or 12 h after 9.25 Gy total body irradiation (TBI) showed increased survival (P = 0.012, 0.011, 0.0002, and 0.017, respectively). CBZ may be a useful radiation protector and mitigator.
    International Journal of Radiation Biology 07/2011; 87(10):1052-60. · 1.84 Impact Factor
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    ABSTRACT: Manganese superoxide dismutase (MnSOD) is a genetically engineered therapeutic DNA/liposome containing the human MnSOD transgene. Preclinical studies in mouse models have demonstrated that the expression of the human MnSOD transgene confers protection of normal tissues from ionizing irradiation damage. This is a phase I study of MnSOD plasmid liposome (PL) in combination with standard chemoradiation in surgically unresectable stage III non-small-cell lung cancer. Chemotherapy (carboplatin and paclitaxel) was given weekly (for 7 weeks), concurrently with radiation. MnSOD PL was swallowed twice a week (total 14 doses), at three dose levels: 0.3, 3, and 30 mg. Dose escalation followed a standard phase I design. Esophagoscopy was done at baseline, day 4, and 6 weeks after radiation with biopsies of the squamous lining cells. DNA was extracted and analyzed by PCR for the detection of the MnSOD transgene DNA. Ten patients with AJCC stage IIIA (three) and IIIB (seven) completed the course of therapy. Five had squamous histology, two adenocarcinoma, one large cell, and two not specified. Patients were treated in three cohorts at three dose levels of MnSOD PL: 0.3 (three patients), 3 (three patients), and 30 mg (four patients). The median dose of radiation was 77.7 Gy (range 63-79.10 Gy). Overall response rate for the standard chemoradiation regimen was 70% (n = 10). There were no dose-limiting toxicities reported in all three dosing tiers. It is concluded that the oral administration of MnSOD PL is feasible and safe. The phase II recommended dose is 30 mg.
    Human gene therapy 03/2011; 22(3):336-42. · 4.20 Impact Factor
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    ABSTRACT: Esophagitis is a significant toxicity of radiation therapy for lung cancer. In this study, reduction of irradiation esophagitis in mice, by orally administered p53/Mdm2/Mdm4 inhibitor, BEB55, or the GS-nitroxide, JP4-039, was evaluated. BEB55 or JP4-039 in F15 (liposomal) formulation was administered intraesophageally to C57BL/6 mice prior to thoracic irradiation of 29 Gy × 1 or 11.5 Gy × 4 thoracic irradiation. Progenitor cells were sorted from excised esophagus, and nitroxide was quantified, by electron paramagnetic resonance (EPR). Mice with Lewis lung carcinoma (3LL) orthotopic lung tumors were treated with BEB55 or JP4-039 prior to 20 Gy to determine if the drugs would protect the tumor cells from radiation. Intraesophageal BEB55 and JP4-039 compared to formulation alone increased survival after single fraction (p=0.0209 and 0.0384, respectively) and four fraction thoracic irradiation (p=0.0241 and 0.0388, respectively). JP4-039 was detected in esophagus, liver, bone marrow, and orthotopic Lewis lung carcinoma (3LL) tumor. There was no significant radiation protection of lung tumors by BEB55 or JP4-039 compared to formulation only as assessed by survival (p=0.3021 and 0.3693, respectively). Thus, BEB55 and JP4-039 safely ameliorate radiation esophagitis in mice.
    In vivo (Athens, Greece) 01/2011; 25(6):841-8. · 1.15 Impact Factor
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    ABSTRACT: The effect of deletion of the nitric oxide synthase 1 gene (NOS1(-/-)) on radiosensitivity was determined. In vitro, long-term cultures of bone marrow stromal cells derived from NOS1(-/-) were more radioresistant than cells from C57BL/6NHsd (wild-type), NOS2(-/-) or NOS3(-/-) mice. Mice from each strain received 20 Gy thoracic irradiation or 9.5 Gy total-body irradiation (TBI), and NOS1(-/-) mice were more sensitive to both. To determine the etiology of radiosensitivity, studies of histopathology, lower esophageal contractility, gastrointestinal transit, blood counts, electrolytes and inflammatory markers were performed; no significant differences between irradiated NOS1(-/-) and control mice were found. Video camera surveillance revealed the cause of death in NOS1(-/-) mice to be grand mal seizures; control mice died with fatigue and listlessness associated with low blood counts after TBI. NOS1(-/-) mice were not sensitive to brain-only irradiation. MnSOD-PL therapy delivered to the esophagus of wild-type and NOS1(-/-) mice resulted in equivalent biochemical levels in both; however, in NOS1(-/-) mice, MnSOD-PL significantly increased survival after both thoracic and total-body irradiation. The mechanism of radiosensitivity of NOS1(-/-) mice and its reversal by MnSOD-PL may be related to the developmental esophageal enteric neuronal innervation abnormalities described in these mice.
    Radiation Research 09/2010; 174(3):297-312. · 2.70 Impact Factor
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    ABSTRACT: To assist in screening existing drugs for use as potential radioprotectors, we used a human unbiased 16,560 short interfering RNA (siRNA) library targeting the druggable genome. We performed a synthetic protection screen that was designed to identify genes that, when silenced, protected human glioblastoma T98G cells from gamma-radiation-induced cell death. We identified 116 candidate protective genes, then identified 10 small molecule inhibitors of 13 of these candidate gene products and tested their radioprotective effects. Glyburide, a clinically used second-generation hypoglycemic drug, effectively decreased radiation-induced cell death in several cell lines including T98G, glioblastoma U-87 MG, and normal lung epithelial BEAS-2B and in primary cultures of astrocytes. Glyburide significantly increased the survival of 32D cl3 murine hematopoietic progenitor cells when administrated before irradiation. Glyburide was radioprotective in vivo (90% of C57BL/6NHsd female mice pretreated with 10 mg/kg glyburide survived 9.5 Gy total-body irradiation compared to 42% of irradiated controls, P = 0.0249). These results demonstrate the power of unbiased siRNA synthetic protection screening with a druggable genome library to identify new radioprotectors.
    Radiation Research 10/2009; 172(4):414-22. · 2.70 Impact Factor
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    ABSTRACT: To determine whether increased mitochondrially localized catalase was radioprotective, a human catalase transgene was cloned into a small pSVZeo plasmid and localized to the mitochondria of 32D cl 3 cells by adding the mitochondrial localization sequence of MnSOD (mt-catalase). The cell lines 32D-Cat and 32D-mt-Cat had increased catalase biochemical activity as confirmed by Western blot analysis compared to the 32D cl 3 parent cells. The MnSOD-overexpressing 32D cl 3 cell line, 2C6, had decreased baseline catalase activity that was increased in 2C6-Cat and 2C6-mt-Cat subclonal cell lines. 32D-mt-Cat cells were more radioresistant than 32D-Cat cells, but both were radioresistant relative to 32D cl 3 cells. 2C6-mt-Cat cells but not 2C6-Cat cells were radioresistant compared to 2C6 cells. Intratracheal injection of the mt-catalase-plasmid liposome complex (mt-Cat-PL) but not the catalase-plasmid liposome complex (Cat-PL) increased the resistance of C57BL/6NHsd female mice to 20 Gy thoracic irradiation compared to MnSOD-plasmid liposomes. Thus mitochondrially targeted overexpression of the catalase transgene is radioprotective in vitro and in vivo.
    Radiation Research 06/2009; 171(5):588-95. · 2.70 Impact Factor
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    ABSTRACT: Fluorescent yellow direct repeat (FYDR) mice carry a transgenic reporter for homologous recombination (HR) and have been used to reveal an age-dependent increase in HR in the pancreas. An established in vitro model system for accelerated aging of the marrow is the mouse long-term bone marrow culture (LTBMC) system. To determine whether the FYDR system, in which an HR event can lead to a fluorescent cell, can be used to study the effects of aging in LTBMCs, clonally expanded hematopoietic and marrow stromal cells in FYDR, positive control FYDR-Recombined (FYDR-Rec), and negative control wild-type C57BL/6NHsd (WT) LTBMCs were analysed. All groups of cultures demonstrated equivalent parameters of continuous hematopoiesis including generation of multilineage colony forming CFU-GM progenitor cells for over 22 weeks and age associated senescence of hematopoiesis. Results indicate that low expression of the FYDR transgene in bone marrow cells in vivo and in vitro prevents the use of the FYDR mice to study rare combination events in bone marrow. Using an alternative approach for detecting HR, namely the sister chromatid exchange (SCE) assay, a statistically significant increase in the number of SCEs per chromosome was observed in adherent cells subcultured from 20-week-compared to 4-week-old LTBMCs. These data suggest that adherent marrow stromal cells from LTBMCs become increasingly susceptible to HR events during aging.
    In vivo (Athens, Greece) 01/2009; 23(5):669-77. · 1.15 Impact Factor
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    ABSTRACT: Manganese superoxide dismutase plasmid liposomes (MnSOD-PL) confer organ-specific in vivo ionizing irradiation protection. To prepare for potential intravenous clinical trials of systemic MnSOD-PL for radioprotection in humans, plasmid and bacterial sequences were removed and a new minicircle construct was tested. Minicircle MnSOD was purified and then cotransfected into 32D cl 3 murine interleukin-3-dependent hematopoietic progenitor cells along with another plasmid carrying the neo gene. Cells were selected in G418 (50 microg/ml) and cloned by limiting dilution. Biochemical analysis of minicircle MnSOD-transfected cells showed an MnSOD biochemical activity level of 5.8 +/- 0.5 U/mg compared with 2.7 +/- 0.1 U/mg for control 32D cl 3 cells (p = 0.0039). 32D-mc-MnSOD cells were as radioresistant as full-length MnSOD-PL transgene-expressing 2C6 cells, relative to 32D cl 3 parent cells, with an increased shoulder on the radiation survival curve (n = 4.8 +/- 0.2 and n = 4.6 +/- 0.2, respectively, compared with 1.5 +/- 0.5 for 32D cl 3 cells; p = 0.007). C57BL/6NHsd mice received intraoral mc-MnSOD-PL, mc-DsRed-PL control, full-length MnSOD-PL, or blank-PL and then were irradiated 24 hr later with 31 Gy to the esophagus. Mice receiving mc-MnSOD-PL showed increased survival compared with control mice or mice treated with mc-DsRed-PL (p = 0.0003 and 0.039, respectively), and comparable to full-length MnSOD-PL. Intravenous, systemic administration of mc-MnSOD-PL protected mice from total body irradiation (9.75 Gy). Therefore, minicircle DNA containing the human MnSOD transgene confers undiminished radioprotection in vitro and in vivo.
    Human gene therapy 09/2008; 19(8):820-6. · 4.20 Impact Factor
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    ABSTRACT: Manganese superoxide dismutase-plasmid liposomes (MnSOD-PL) confer organ specific in vivo ionizing irradiation protection. To prepare for potential intravenous clinical trials of systemic MnSOD-PL for radioprotection in humans, plasmid and bacterial sequences were removed and a new mini circle construct was tested. Mini circle-MnSOD was purified and then co-transfected into 32D cl 3 murine IL-3 dependent hematopoietic progenitor cells along with another plasmid containing the neo gene. Cells were selected in G418 (50 microg/ml) and cloned by limiting dilution. Biochemical analysis of mini circle MnSOD transfected cells showed 5.8 + 0.5 U/mg MnSOD biochemical activity compared to 2.7 + 0.1 U/mg for control 32D cl 3 cells (p = 0.0039). 32D-MC-MnSOD cells were comparably radioresistant to full length MnSOD-PL transgene 2C6 cells, relative to 32D cl 3 parent cells, with an increased shoulder on the radiation survival curve (ñ = 4.8 + 0.2 and ñ = 4.6 + 0.2 respectively compared to 1.5 + 0.5 for 32D cl 3, p = 0.007). C57BL/6NHsd mice received intra-oral MC-MnSOD-PL, MC-DS-red-PL control, full length MnSOD-PL, or blank-PL then were irradiated 24 hours later to 31 Gy to the esophagus. Mice receiving MC-MnSOD-PL showed increased survival compared to control mice or mice treated with MC-DS-red-PL (p = 0.0099, or 0.039, respectively), and comparable to full length MnSOD-PL. Intravenous, systemic administration of MC-MnSOD-PL protected mice from 9.75 Gy total body irradiation. Therefore, mini circle DNA containing the human MnSOD transgene confers undiminished radioprotection in vitro and in vivo. Supported by U19A1068021 of the NIAID/NIH.
    Human Gene Therapy 07/2008; · 4.02 Impact Factor
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    ABSTRACT: Ethyl pyruvate (EP), a simple aliphatic ester of pyruvic acid, has been shown to improve survival and ameliorate organ damage in animal models of sepsis, ischemia/reperfusion injury and hemorrhagic shock. Incubating IL3-dependent mouse hematopoietic progenitor cell 32Dcl3 cells before or after irradiation with 10 mM EP increased resistance to radiation as assessed by clonogenic radiation survival curves, decreased release of mitochondrial cytochrome C into the cytoplasm, and decreased apoptosis. EP inhibited radiation-induced caspase 3 activation and poly(ADP-ribose) polymerase (PARP) cleavage in 32Dcl3 cells in a concentration-dependent fashion. EP was given i.p. to C57BL/6NHsd mice irradiated with 9.75 Gy total-body irradiation (TBI). This treatment significantly improved survival. The survival benefit was apparent irrespective of whether treatment with EP was started 1 h before TBI and continued for 5 consecutive days after TBI or the compound was injected only 1 h before or only for 5 days after TBI. In all of the in vitro and in vivo experiments, ethyl lactate, an inactive analogue of EP, had no detectable radioprotective or mitigating effects. EP may be an effective radioprotector and mitigator of the hematopoietic syndrome induced by TBI.
    Radiation Research 12/2007; 168(5):552-9. · 2.70 Impact Factor
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    ABSTRACT: We determined whether manganese superoxide dismutase (MnSOD)-plasmid liposome (PL) transfection of C57BL/ 6NHsd mouse bone marrow protected cells irradiated at room temperature (24 degrees C) or in the cryopreserved state. MnSOD-overexpressing hematopoietic progenitor 2C6 cells were radioresistant compared to the parent 32D cl 3 cells when irradiated frozen or at 24 degrees C. Fresh whole marrow from mice injected intravenously with MnSOD-PL prior to explant as well as explanted marrow single cell suspensions transfected in vitro were irradiated at 24 degrees C or -80 degrees C. In vivo or in vitro transfection of marrow with MnSOD-PL produced significant radiation protection of irradiated marrow progenitor cells compared to controls at 24 degrees C or -80 degrees C. (in vivo transfection D(0) 2.19 +/- 0.21 at 24 degrees C, D(0) 2.10 +/- 0.07 at -80 degrees C compared to control D(0) 1.56 +/- 0.06 or 1.66 +/- 0.04, P = 0.047 and 0.017 respectively; in vitro transfection D(0) 2.35 +/- 0.11 at 24 degrees C, D(0) 3.42 +/- 0.13 at -80 degrees C compared to D(0) 1.81 +/- 0.01 or 2.53 +/- 0.05, P = 0.0087 and 0.0026, respectively). Thus the MnSOD transgene product protects frozen marrow cells as well as marrow cells irradiated at 24 degrees C.
    Radiation Research 12/2007; 168(5):560-6. · 2.70 Impact Factor