Hongliang Guo

Prevention of Radiation-Induced Oral Cavity Mucositis by Plasmid/Liposome Delivery of the Human Manganese Superoxide Dismutase (SOD2) Transgene

Abstract Guo, H., Seixas-Silva, Jr., J. A., Epperly, M. W., Gretton, J. E., Shin, D. M., Bar-Sagi, D., Archer, H. and Greenberger, J. S. Prevention of Radiation-Induced Oral Cavity Mucositis by Plasmid/Liposome Delivery of the Human Manganese Superoxide Dismutase (SOD2) Transgene. Radiat. Res. 159, 361–370 (2003). Oral cavity mucositis is a major toxicity of radiation therapy for head and neck cancer. In the present mouse model studies, we evaluated intraoral administration of SOD2-PL complexes 24 h before single-fraction 30-Gy irradiation for the prevention of oral cavity mucositis. Expression of the human SOD2 transgene in the oral cavity of C3H/HeNsd mice was demonstrated by nested reverse transcriptase polymerase chain reaction (RT-PCR). Mice treated intraorally with bacterial β-galactosidase gene-plasmid/liposome (LacZ-PL) or hemagglutinin (HA)-manganese superoxide dismutase-plasmid/liposome (HA-SOD2-PL) demonstrated LacZ or HA-SOD2 expression, respectively, 24 h after injection. In a second strain of mouse, SOD2-PL-treated female athymic nude mice demonstrated significantly decreased ulceration at day 5 after 30 Gy, compared to LacZ-PL-injected, irradiated mice or irradiated controls. No further reduction in radiation-induced ulceration was detected in mice treated with both SOD2-PL and 10 mg/kg of amifostine (WR-2721) 30 min before 30 Gy compared to SOD2-PL alone. No significant protection of orthotopically transplanted murine squamous cell carcinoma (SCC-VII) tumors was detected in mice that received SOD2-PL treatment before 18 Gy. Thus overexpression of human SOD2 in the oral cavity mucosa can prevent radiation-induced mucositis with no detectable compromise in the therapeutic response of orthotopically transplanted tumors.

Bone Marrow Origin of Cells with Capacity for Homing and Differentiation to Esophageal Squamous Epithelium

Abstract Epperly, M. W., Guo, H., Shen, H., Niu, Y., Zhang, X., Jefferson, M., Sikora, C. A. and Greenberger, J. S. Bone Marrow Origin of Cells with Capacity for Homing and Differentiation to Esophageal Squamous Epithelium. Radiat. Res. 162, 233–240 (2004). Our goal was to determine whether esophageal progenitor cells could be isolated from adult mouse esophagus or bone marrow and shown to home to and proliferate in the irradiated esophagus of recipient mice. Esophageal progenitor cells were isolated from adult male C3H/HeNsd or C57BL/6J green fluorescent protein (GFP+) mice by a serial in vitro preplate technique or the technique of side population cell sorting. When injected intravenously (i.v.), these cells homed to the 30-Gy-irradiated esophagus of GFP− female recipient mice and formed donor-origin esophageal foci. GFP+ whole murine bone marrow cells injected i.v. also formed donor-origin esophageal squamous cell foci and protected recipient GFP− mice from upper-body irradiation in a cell dose-dependent manner. Marrow chimeric GFP− mice reconstituted with GFP+ cells showed migration of GFP+ marrow cells to the esophagus after 30 Gy irradiation. Purified esophageal progenitor cells isolated from first-generation preplate cell recipients engrafted after i.v. injection to the esophagus of second-generation-irradiated recipient mice. These data establish that esophageal progenitor cells can home to the irradiated esophagus and show limited differentiation capacity to squamous epithelium.

Cell phenotype specific kinetics of expression of intratracheally injected manganese superoxide dismutase–plasmid/liposomes (MnSOD–PL) during lung radioprotective gene therapy

Intratracheal (IT) injection of manganese superoxide dismutase–plasmid/liposome (MnSOD-PL) complexes prior to whole lung irradiation of C57BL/6J mice provides significant protection from acute and chronic irradiation damage. We determined the duration of increased MnSOD biochemical activity and differential expression of a hemagglutinin (HA) epitope-tagged MnSOD transgene. HA–MnSOD–PL was IT injected at doses of 0–1000 μg, and mice were killed 1,2,3 or 4 days later. Other groups of mice were irradiated to 20 Gy to the pulmonary cavity 24 h after injection and killed at the same time points as non-irradiated mice. Both non-irradiated and irradiated groups of mice showed increased MnSOD biochemical activity with plasmid dose that plateaued at 100 μg of MnSOD plasmid DNA. In control mice, MnSOD biochemical activity decreased at 2, 3 or 4 days after injection. In irradiated mice, MnSOD biochemical activity decreased at day 2 but increased on days 3 and 4. HA–MnSOD expression decreased in broncheoalveolar macrophages and alveolar type-II cells 3 days after injection in non-irradiated and irradiated mice, but remained elevated in endothelial and epithelial cells past 4 days. The data provide a rationale for every second-day administration of intrapulmonary MnSOD–PL in clinical trials of radioprotective gene therapy. This should be sufficient to provide radioprotection during radiation treatments.