Irradiated Esophageal Cells are Protected from Radiation-Induced Recombination by MnSOD Gene Therapy

Radiation-induced DNA damage is a precursor to mutagenesis and cytotoxicity. During radiotherapy, exposure of healthy tissues can lead to severe side effects. We explored the potential of mitochondrial SOD (MnSOD) gene therapy to protect esophageal, pancreatic and bone marrow cells from radiation-induced genomic instability. Specifically, we measured the frequency of homologous recombination (HR) at an integrated transgene in the Fluorescent Yellow Direct Repeat (FYDR) mice, in which an HR event can give rise to a fluorescent signal. Mitochondrial SOD plasmid/liposome complex (MnSOD-PL) was administered to esophageal cells 24 h prior to 29 Gy upper-body irradiation. Single cell suspensions from FYDR, positive control FYDR-REC, and negative control C57BL/6NHsd (wild-type) mouse esophagus, pancreas and bone marrow were evaluated by flow cytometry. Radiation induced a statistically significant increase in HR 7 days after irradiation compared to unirradiated FYDR mice. MnSOD-PL significantly reduced the induction of HR by radiation at day 7 and also reduced the level of HR in the pancreas. Irradiation of the femur and tibial marrow with 8 Gy also induced a significant increase in HR at 7 days. Radioprotection by intraesophageal administration of MnSOD-PL was correlated with a reduced level of radiation-induced HR in esophageal cells. These results demonstrate the efficacy of MnSOD-PL for suppressing radiation-induced HR in vivo.National Institutes of Health (U.S.) (NIH Grant R01-CA83876-8)National Institute of Allergy and Infectious Diseases (U.S.) (NIH grant U19A1068021)National Institutes of Health (U.S.) (Grant T32-ES07020)United States. Dept. of Energy (DOE DE-FG01-04ER04)National Institutes of Health (U.S.) (NIH P01-CA26735

Strategies for Discovery of Small Molecule Radiation Protectors and Radiation Mitigators

Mitochondrial targeted radiation damage protectors (delivered prior to irradiation) and mitigators (delivered after irradiation, but before the appearance of symptoms associated with radiation syndrome) have been a recent focus in drug discovery for (1) normal tissue radiation protection during fractionated radiotherapy, and (2) radiation terrorism counter measures. Several categories of such molecules have been discovered: nitroxide-linked hybrid molecules, including GS-nitroxide, GS-nitric oxide synthase inhibitors, p53/mdm2/mdm4 inhibitors, and pharmaceutical agents including inhibitors of the phosphoinositide-3-kinase pathway and the anti-seizure medicine, carbamazepine. Evaluation of potential new radiation dose modifying molecules to protect normal tissue includes: clonogenic radiation survival curves, assays for apoptosis and DNA repair, and irradiation-induced depletion of antioxidant stores. Studies of organ specific radioprotection and in total body irradiation-induced hematopoietic syndrome in the mouse model for protection/mitigation facilitate rational means by which to move candidate small molecule drugs along the drug discovery pipeline into clinical development

Blocking the formation of radiation–induced breast cancer stem cells

The goal of adjuvant (post-surgery) radiation therapy (RT) for breast cancer (BC) is to eliminate residual cancer cells, leading to better local tumor control and thus improving patient survival. However, radioresistance increases the risk of tumor recurrence and negatively affects survival. Recent evidence shows that breast cancer stem cells (BCSCs) are radiation-resistant and that relatively differentiated BC cells can be reprogrammed into induced BCSCs (iBCSCs) via radiation-induced re-expression of the stemness genes. Here we show that in irradiation (IR)-treated mice bearing syngeneic mammary tumors, IR-induced stemness correlated with increased spontaneous lung metastasis (51.7%). However, IR-induced stemness was blocked by targeting the NF-κB- stemness gene pathway with disulfiram (DSF)and Copper (Cu2+). DSF is an inhibitor of aldehyde dehydrogenase (ALDH) and an FDA-approved drug for treating alcoholism. DSF binds to Cu2+ to form DSF-Cu complexes (DSF/Cu), which act as a potent apoptosis inducer and an effective proteasome inhibitor, which, in turn, inhibits NF-κB activation. Treatment of mice with RT and DSF significantly inhibited mammary primary tumor growth (79.4%) and spontaneous lung metastasis (89.6%) compared to vehicle treated mice. This anti-tumor efficacy was associated with decreased stem cell properties (or stemness) in tumors. We expect that these results will spark clinical investigation of RT and DSF as a novel combinatorial treatment for breast cancer

Microneedle array delivered recombinant coronavirus vaccines: Immunogenicity and rapid translational development

Background: Coronaviruses pose a serious threat to global health as evidenced by Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), and COVID-19. SARS Coronavirus (SARS-CoV), MERS Coronavirus (MERS-CoV), and the novel coronavirus, previously dubbed 2019-nCoV, and now officially named SARS-CoV-2, are the causative agents of the SARS, MERS, and COVID-19 disease outbreaks, respectively. Safe vaccines that rapidly induce potent and long-lasting virus-specific immune responses against these infectious agents are urgently needed

The HSP90 Inhibitor Ganetespib Radiosensitizes Human Lung Adenocarcinoma Cells

The molecular chaperone HSP90 is involved in stabilization and function of multiple client proteins, many of which represent important oncogenic drivers in NSCLC. Utilization of HSP90 inhibitors as radiosensitizing agents is a promising approach. The antitumor activity of ganetespib, HSP90 inhibitor, was evaluated in human lung adenocarcinoma (AC) cells for its ability to potentiate the effects of IR treatment in both in vitro and in vivo. The cytotoxic effects of ganetespib included; G2/M cell cycle arrest, inhibition of DNA repair, apoptosis induction, and promotion of senescence. All of these antitumor effects were both concentration- and time-dependent. Both pretreatment and post-radiation treatment with ganetespib at low nanomolar concentrations induced radiosensitization in lung AC cells in vitro. Ganetespib may impart radiosensitization through multiple mechanisms: such as down regulation of the PI3K/Akt pathway; diminished DNA repair capacity and promotion of cellular senescence. In vivo, ganetespib reduced growth of T2821 tumor xenografts in mice and sensitized tumors to IR. Tumor irradiation led to dramatic upregulation of β-catenin expression in tumor tissues, an effect that was mitigated in T2821 xenografts when ganetespib was combined with IR treatments. These data highlight the promise of combining ganetespib with IR therapies in the treatment of AC lung tumors

Gene Therapy for Systemic or Organ Specific Delivery of Manganese Superoxide Dismutase

Manganese superoxide dismutase (MnSOD) is a dominant component of the antioxidant defense system in mammalian cells. Since ionizing irradiation induces profound oxidative stress, it was logical to test the effect of overexpression of MnSOD on radioresistance. This task was accomplished by introduction of a transgene for MnSOD into cells in vitro and into organs in vivo, and both paradigms showed clear radioresistance following overexpression. During the course of development and clinical application of using MnSOD as a radioprotector, several prominent observations were made by Larry Oberley, Joel Greenberger, and Michael Epperly which include (1) mitochondrial localization of either manganese superoxide dismutase or copper/zinc SOD was required to provide optimal radiation protection; (2) the time required for optimal expression was 12–18 h, and while acceptable for radiation protection, the time delay was impractical for radiation mitigation; (3) significant increases in intracellular elevation of MnSOD activity were required for effective radioprotection. Lessons learned during the development of MnSOD gene therapy have provided a strategy for delivery of small molecule SOD mimics, which are faster acting and have shown the potential for both radiation protection and mitigation. The purpose of this review is to summarize the current status of using MnSOD-PL and SOD mimetics as radioprotectors and radiomitigators

Manganese [correction of Magnesium] superoxide dismutase (MnSOD) plasmid/liposome pulmonary radioprotective gene therapy: Modulation of irradiation-induced mRNA for IL-I, TNF-alpha, and TGF-beta correlates with delay of organizing alveolitis/fibrosis

AbstractRadiation pneumonitis remains a critical dose-limiting toxicity of total body irradiation (TBI) for use in bone marrow transplantation. The acute and chronic phases of radiation damage in the mouse lung have been shown to correlate with mouse strain genotype and are dependent on fraction size, total dose, and total lung volume. Our prior studies demonstrated effective prevention of irradiation-induced lung damage and improved survival in C57BL/6J mice by MnSOD plasmid/liposome gene therapy. In the present studies, we investigated the kinetics of irradiation-induced upregulation of mRNA for acute phase cytokines interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha, and fibrosis-associated transforming growth factor (TGF)-beta and isoforms (TGF-beta1, TGF-beta2 and TGF-beta3) in 2000 cGy whole-lung irradiated C57BL/6J mice, a strain known to develop dose and volume-dependent organizing alveolitis/fibrosis. The results demonstrate increase in mRNA for IL-1 between days 1 and 14 after irradiation with return to baseline levels out to 120 days. TNF-alpha mRNA levels were not initially elevated but increased between 80 and 100 days and then decreased by 120 days. The mRNA levels for TGF-beta1 demonstrated an initial increase within the first 14 days after total lung irradiation with a decrease to baseline levels out to 100 days. Then, in striking contrast to the other two cytokines, an increase in TGF-beta2 mRNA occurred at around 120 days and correlated with the detection of organizing alveolitis/radiation fibrosis and mortality. These results are consistent with a two-phase mechanism in the molecular pathology of irradiation lung injury, in which IL-1 cytokine mRNA levels correlated with the acute pneumonitis phase and delayed elevation of TNF-alpha (80-100 days), TGF-beta1 (100 days), and TGF-beta2 (120 days) were associated with the fibrosis phase. Insight into the cell-specific and tissue-specific molecular mechanisms of ionizing irradiation induction of mRNA for pulmonary cytokines may provide new strategies for treatment of radiation pneumonitis in TBI patients.Biol Blood Marrow Transplant 1999;5(4):204-14

Redox Gene Therapy Protects Human IB-3 Lung Epithelial Cells Against Ionizing Radiation-Induced Apoptosis

Toxicity to nontumor-derived tissue has proven to be a significant obstacle in achieving therapeutic levels of gamma irradiation in the treatment of cancer. The formation of reactive oxygen species (ROS) such as superoxide radicals (O2-) following irradiation is thought to be a major determinant of cellular damage. To this end, we describe the generation of two recombinant adenoviral vectors expressing the radical-scavenging enzymes MnSOD and CuZnSOD to test therapeutic strategies of radioprotection. Using a human lung epithelial cell line (IB-3), we have demonstrated that infections with both Ad.CMVMnSOD or Ad.CMVCuZnSOD significantly increase both the levels of SOD protein and enzymatic activity as compared to control cells. This increase in SOD expression reduced the level of apoptosis at 72 hr post-irradiation by 50% as compared to mock- or Ad.CMVLacZ-infected cells. Such studies provide the foundation for radioprotective gene therapies in the treatment of cancer