Amelioration of Mucositis in Proton Therapy of Fanconi Anemia Fanca-/- Mice by JP4-039

BACKGROUND/AIM

We tested JP4-039, a GS-nitroxide radiation damage mitigator in proton therapy of Fanconi anemia (FA) mice.

MATERIALS AND METHODS

Fanca^-/- and Fanca^+/+ bone marrow stromal cells were pre-treated with JP4-039 and irradiated with either protons or photons (0-10 GyRBE) followed by clonogenic survival and β-Galactosidase senescence analysis. Fanca^-/- and Fanca^+/+ mice were pretreated with JP4-039 for 10 min prior to oropharyngeal irradiation with either protons or photons (0 or 30 GyRBE) followed by sacrifice and measurement of oral cavity ulceration, distant hematopoietic suppression, and real-time polymerase chain reaction analysis.

RESULTS

JP4-039 reduced oral cavity ulceration in Fanca^-/- mice, transcripts Nfkb, Ap1, Sp1, and Nrf2, and proton therapy induced distant marrow suppression.

CONCLUSION

JP4-039 protected Fanca^-/- and Fanca^+/+ cells and mouse oral cavity from both proton and photon radiation.

Abstract 2913: Serpinb3a-/- mice are radioresistant

Serpins are a superfamily of serine protease inhibitors that regulate proteolytic pathways by utilizing a conformational change to bind to and inhibit their target peptidases. Currently 36 human serpins have been identified, but the biological roles of most are not fully understood (Silverman et al., J Biol Chem. 285(32):24299-305, 2010). Serpinb3a (the mouse orthologue of human SERPINB3 and -B4) is an intracellular serpin and inhibits both serine and cysteine peptidases invitro. We now report radioresistance of Serpinb3a-/- mice and their hematopoietic progenitor cells. Serpinb3a-/- and control Balb/c mice were irradiated to a dose of 8.0 Gy total body irradiation and followed for the development of the hematopoietic syndrome. Long Term Bone Marrow Cultures (LTBMCs) were established from the bone marrow flushed from the femurs and tibias of Serpinb3a-/- and Balb/c mice. Irradiation survival curves were performed on bone marrow stromal cell lines established from the LTBMCs and on fresh bone marrow isolated from the femurs of sacrificed Serpinb3a-/- and Balb/c mice. Colony forming unit granulocyte-macrophage (CFU-GM) colonies of 50 cells or greater were counted. The data from 3 experiments were analyzed using linear quadratic and single-hit, multi-target models. Serpinb3a-/- mice showed increased survival following 8.0 Gy TBI compared to Balb/c mice (p < 0.0001). CFU-GM from Serpinb3a-/- were radioresistant compared to Balb/c marrow (ň = 4.9 ± 1.4 and 1.4 ± 0.1, p = 0.0451, respectively). Serpinb3a-/- bone marrow stromal cells were radioresistant with an increased Do (1.97 + 0.11 Gy) compared to bone marrow stromal cells from Balb/c mice (Do = 1.45 + 0.03 Gy, p = 0.0113). Loss of Serpinb3a provides a radiation survival advantage, increases radioresistance of both hematopoietic progenitor cells and marrow stromal cells, and may lead to identification of new targets for design of radiation mitigator drugs.

This research was supported by grant NIAID/NIH U19-A168021.

Citation Format: Stephanie Thermozier, Michael Epperly, Darcy Franicola, Xichen Zhang, Renee Fisher, Donna Shields, Hong Wang, John Willis, Cliff Luke, Gary Silverman, Joel Greenberger. Serpinb3a-/- mice are radioresistant [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2913.

Amelioration of Amyotrophic Lateral Sclerosis in SOD1G93A Mice by M2 Microglia from Transplanted Marrow

Background/Aim: The cause of fatal neuromuscular amyotrophic lateral sclerosis (ALS) is not known. Materials and Methods: Ninety-day-old superoxide-dismutase-1 G93A (SOD1 G93A ) mice demonstrating level 1 paralysis, received 9.0 Gy total body irradiation (TBI) from a cesium source at 340 cGy per minute, and intravenous transplantation with 1×10 6 C57BL/6 green fluorescent protein (GFP)+ donor bone marrow cells. Results: Paralysis-free survival was prolonged in TBI and bone marrow-transplanted SOD1 G93A mice from 100 to over 250 days (p=0.0018). Other mice transplanted with SOD1 G93A marrow or marrow treated with the free-radical scavenger MMS350 showed no therapeutic effect. GFP+ macrophage-2 (M2) microglial cells of bone marrow origin, were seen at sites of degenerating anterior horn motor neurons. SOD1 G93A mice had a disruption in the blood-brain barrier permeability which was reversed by marrow transplant from C57BL/6 mice. SOD1 G93A marrow showed unexpected robust hematopoiesis in vitro, and radioresistance. Conclusion: After TBI, M2 microglial cells from transplanted donor marrow extended the paralysis-free interval in SOD1 G93A mice.

Malignant Transformation of Fanconi Anemia Complementation Group D2-deficient (Fancd2 -/-) Hematopoietic Progenitor Cells by a Single HPV16 Oncogene

AIM

To demonstrate that Fanconi anemia complementation group D2-deficient (Fancd2^-/-) hematopoietic progenitor cell lines can be transformed by transfection with a plasmid containing either the E6 or E7 oncogene of human papillomavirus (HPV) to generate malignant plasmacytoma-inducing cell lines.

MATERIALS AND METHODS

In order to determine whether a single HPV type 16 (HPV16) oncogene induced malignant transformation, Fancd2^-/- and Fancd2^+/+ interleukin 3 (IL3)-dependent hematopoietic progenitor cell lines were transfected with plasmids containing E6 or E7 oncogene, or control empty plasmid.

RESULTS

Fancd2^-/- but not Fancd2^+/+ cells were transformed into malignant IL3-independent cells by both E6, and E7 oncogenes, but not by empty plasmid. Hematopoietic cell lines and tumors induced by Fancd2^-/- E6 and Fancd2^-/- E7 cell lines were positive for each respective HPV RNA and protein.

CONCLUSION

A single HPV16 oncogene is adequate to produce malignant transformation of Fancd2^-/- hematopoietic cells.

Continuous One Year Oral Administration of the Radiation Mitigator, MMS350, after Total-Body Irradiation, Restores Bone Marrow Stromal Cell Proliferative Capacity and Reduces Senescence in Fanconi Anemia (Fanca-/-) Mice

We quantitated age-related accumulation of senescent cells in irradiated Fanconi anemia (FA) (Fanca^-/- mouse cell lines in vitro, and monitored the effect of continuous administration (via drinking water) of the water-soluble radiation mitigator, MMS350, on tissues in vivo over one year after 7.5 Gy total-body irradiation (TBI). Irradiated Fanca^-/- mouse bone marrow stromal cell lines showed increased numbers of beta-galactosidase- and p21-positive senescent cells compared to Fanca^+/+ cell lines, which was reduced by MMS350. One week after 7.5 Gy TBI, Fanca^-/- mice showed increased numbers of senescent cells in spleen compared to Fanca^+/+ controls, decreased bone marrow cellularity, failure of explanted bone marrow to proliferate in vitro to form a hematopoietic microenvironment and no detectable single stromal cell cloning capacity. There was no detectable amelioration by MMS350 administration at one week. In contrast, one year post-TBI, Fanca^-/- mice demonstrated fewer senescent cells in brain and spleen compared to Fanca^+/+ controls. While Fanca^-/- mouse bone marrow stromal cells explanted one year post-TBI still failed to proliferate in vitro, continuous oral administration of 400 µ M, MMS350 in drinking water restored explanted stromal cell proliferation. The data indicate that continuous administration of MMS350 modulated several properties of TBI-accelerated aging in Fanca^-/- mice as well as control mice, and support further study of MMS350 as a modulator of radiation late effects.

Evaluation of Different Formulations and Routes for the Delivery of the Ionizing Radiation Mitigator GS-Nitroxide (JP4-039)

BACKGROUND/AIM

The mitochondrial targeted GS-nitroxide, JP4-039, is an effective total body irradiation (TBI) mitigator when delivered intravenously (IV) up to 72 h after exposure. Effective systemic and localized administration to oral cavity/oropharynx and esophagus has been demonstrated. The objective of the study was to establish alternatives to IV administration suitable for JP4-039 delivery to mass casualties.

MATERIALS AND METHODS

JP4-039 was administered to C57BL/6 mice by topically applied carboxy-methyl-cellulose microneedle arrays (MNAs) or by intramuscular (IM) injection. Three different formulations that have passed Food and Drug Administration review, namely Captisol, 2-hydroxypropyl-β-cyclodextrin (cyclodextrin), and Miglyol-812-N, were used for drug delivery. Intraoral (IO) administration with each formulation was also evaluated.

RESULTS

All tested formulations and MNAs successfully delivered JP4-039. However, IM delivery of the Miglyol-812-N displayed very efficient and highly reproducible radiation mitigation.

CONCLUSION

Effective IM delivery of JP4-039 in animal models after TBI or partial-body irradiation suggested the use of the Miglyol-812-N formulation in both medical indications and radiation countermeasures.

Induction of TGF-β by Irradiation or Chemotherapy in Fanconi Anemia (FA) Mouse Bone Marrow Is Modulated by Small Molecule Radiation Mitigators JP4-039 and MMS350

BACKGROUND/AIM

Total-body irradiation and/or administration of chemotherapy drugs in bone marrow transplantation induce cytokines that can suppress engraftment. Fanconi Anemia (FA) patients have a hyperactive responsiveness to the inhibitory cytokine, transforming growth factor-beta (TGF-β). Small molecule radiation mitigator drugs, JP4-039 and MMS350, were evaluated for suppression of irradiation or drug-induced TGF-β.

MATERIALS AND METHODS

In vivo induction of TGF-β by total-body ionizing irradiation (TBI), L-phenylalanine mustard (L-PAM), busulfan or fludarabine, was quantified. In parallel, mitigator drug amelioration of TGF-β induction in FA D2^-/- (FANCD2^-/-) mouse bone marrow, was studied in vitro. Tissue culture medium, cell lysates, and mouse plasma were analyzed for TGF-β levels.

RESULTS

Induction of TGF-β levels in FANCD2^-/- and FANCD2^+/+ mice and in mouse bone marrow were modulated by both JP4-039 and MMS350.

CONCLUSION

Bone marrow transplantation in FA recipients may benefit from administration of small molecule agents that suppress TGF-β induction.

Reduced Competitive Repopulation Capacity of Multipotential Hematopoietic Stem Cells in the Bone Marrow of Friend Virus-infected Fv2-resistant Mice

BACKGROUND/AIM

The polycythemia form of Friend leukemia virus (FVP) causes splenomegaly and lethal erythroleukemia in Fv-2^s-susceptible mouse strains. We sought to determine whether the hematopoietic stem cell (HSC) pool was expanded in Fv-2^r-resistant mice.

MATERIALS AND METHODS

The 120-day bone marrow transplantation competitive repopulation assay was used to determine whether FVP-infected Fv-2^r C57BL/6 mice demonstrated expansion of the HSC pool compared to the pool of committed hematopoietic progenitor cells in the same marrow assayed in vitro.

RESULTS

There was a significant expansion of committed hematopoietic progenitors observed in virus-infected Fv-2^s FVB mice, but not Fv-2^r C57BL/6 mice. Furthermore, Fv-2^r mice showed no detectable expansion of either committed hematopoietic progenitor cells or the multipotential stem cell pool by competitive repopulation assay.

CONCLUSION

Friend virus disease in Fv-2^s mice is associated with expansion of committed hematopoietic progenitors. Fv-2^r mice show no expansion of either committed progenitor or pluripotential stem cell numbers.

Evolution of malignant plasmacytoma cell lines from K14E7 Fancd2-/- mouse long-term bone marrow cultures

We tested the effect of expression of the Human Papilloma Virus (HPV E7) oncogene on hematopoiesis in long-term bone marrow cultures (LTBMCs) derived from K14E7 (FVB) Fancd2-/- (129/Sv), K14E7 Fancd2+/+, Fancd2-/-, and control (FVB X 129/Sv) Fl mice. K14E7 Fancd2-/- and Fancd2-/- LTBMCs showed decreased duration of production of total nonadherent hematopoietic cells and progenitors forming day 7 and day 14 multilineage CFU-GEMM colonies in secondary cultures (7 wks and 8 wks respectively) compared to cultures from K14E7 Fancd2+/+ (17 wks) or control mice (18 wks) p < 0.0001. Marrow stromal cell lines derived from both K14E7 Fancd2-/- and Fancd2-/- cultures were radiosensitive, as were IL-3 dependent hematopoietic progenitor cell lines derived from K14E7 Fancd2-/- cultures. In contrast, Fancd2-/- mouse hematopoietic progenitor cell lines and fresh marrow were radioresistant. K14E7 Fancd2-/- mouse freshly explanted bone marrow expressed no detectable K14 or E7; however, LTBMCs produced K14 positive factor-independent (FI) clonal malignant plasmacytoma forming cell lines in which E7 was detected in the nucleus with p53 and Rb. Transfection of an E6/E7 plasmid into Fancd2-/-, but not control Fancd2+/+ IL-3 dependent hematopoietic progenitor cell lines, increased cloning efficiency, cell growth, and induced malignant cell lines. Therefore, the altered radiobiology of hematopoietic progenitor cells and malignant transformation in vitro by K14E7 expression in cells of the Fancd2-/- genotype suggests a potential role of HPV in hematopoietic malignancies in FA patients.

Abstract 1655: Expression of the HPV E7 oncogene in K14E7Fancd2-/- mouse long term bone marrow culture derived hematopoietic cells produces malignant plasmacytomas

Introduction: Transgenic FVB/n mice with the HPV E7 oncogene under the control of the CK14 promoter were bred with Fancd2+/- (129/Sv background) mice to obtain K14E7 Fancd2-/- mice Park, et al. Cancer Research, 70(23): 9959, 2010), in which delivery of 4-nitroquinoline N-oxide in drinking water produces oral and esophageal adenomas. The hematopoietic system, of these mice was studied, using long term bone marrow cultures (LTBMCs) from Fancd2-/- (SV129), K14E7 transgenic (FVB/n), and K14E7 Fancd2-/- mice.

Methods: LTBMCs were established by flushing bone marrow into T-25 flasks from which bone marrow stromal cell lines and IL3-dependent hematopoietic cell lines were developed. The cell lines were analyzed using irradiation survival curves, Western analysis for protein expression. K14E7 Fancd2-/- IL3 dependent clonal cell lines of the IL3-dependent cell lines were established by flow cytometry. Clonal lines were expanded and tested for tumorigenicity by injecting 1 × 106 cells of each of four clones into flanks of K14E7 Fancd2+/+ mice.

Results: K14E7 Fancd2-/- LTBMCs were similar to those from Sv/129 Fancd2-/-: 1) hematopoiesis was shortened when compared to K14E7 Fancd2+/+ or Fancd2+/+ LTBMCs, respectively. Stromal cell line irradiation survival curves with K14E7 Fancd2+/+ and Fancd2-/- cell lines showed (Do = 1.48 ± 0.05 and 1.52 ± 0.15 Gy) they were radiosensitive compared to those from K14E7 Fancd2+/+ or Sv/129 Fancd2+/+ cells (Do = 2.33 ± 0.11 and 2.23 ± 0.01 Gy, p = 0.0043 and 0.0368, respectively). Fancd2-/- stromal cells were more radiosensitive than Fancd2+/+ cells (decreased shoulder on the survival curve of n = 1.5 ± 0.5 compared to 4.7 ± 0.3 (p = 0.0126). K14E7Fancd2+/+ cells had an n of 1.9 ± 0.3 compared to 3.5 ± 0.1 (p = 0.0309) for Sv/129 cells. In contrast, hematopoietic IL-3 dependent K14E7Fancd2+/+ and Sv/129 Fancd2+/+ cell lines were similar (Do = 2.15 ± 0.4 and 1.92 ± 0.06, p = 0.6469, respectively). Confirming prior data, (Berhane et. al, Rad Res 182: 35, 2014) Sv/129 Fancd2-/- IL-3 dependent cell lines were radioresistant compared to Fancd2+/+ cell lines (Do = 2.12 ± 0.12 and 1.92 ± 0.06, respectively, p = 0.0236). In contrast, K14E7 Fancd2-/- cell lines were radiosensitive compared to K14E7 Fancd2+/+ cell lines (1.44 ± 0.13 and 2.15 ± 0.28, respectively, p = 0.0498). Hematopoietic and marrow stromal cell lines from K14E7Fancd2-/- marrow expressed cytokeratin 14 and E7 oncogene by Western analysis. K14E7 Fancd2-/- (but no other genotype derived) IL-3 dependent cell lines transformed in vitro to dense tumor cells lines. Cloned sublines were injected into K14E7 Fancd2+/- mice producing plasmacytomas.

Conclusions: Expression of the E7 oncogene in the K14/E7 Fancd2-/- mouse marrow derived IL-3 dependent cell lines leads to radiosensitivity and tumorgenicity.

Supported by NIAID/NIH U19-A 1068021 and the Fanconi Anemia Research Foundation.

Citation Format: Joel S. Greenberger, Lora Rigatti, Aranee Sivanathan, Shaonan Cao, Xichen Zhang, Donna Shields, Darcy Franicola, Michael Epperly. Expression of the HPV E7 oncogene in K14E7Fancd2-/- mouse long term bone marrow culture derived hematopoietic cells produces malignant plasmacytomas. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1655.

Intraoral Mitochondrial-Targeted GS-Nitroxide, JP4-039, Radioprotects Normal Tissue in Tumor-Bearing Radiosensitive Fancd2(-/-) (C57BL/6) Mice

We evaluated normal tissue specific radioprotection of the oral cavity in radiosensitive Fanconi Anemia (FA) Fancd2(-/-) mice with orally established tumors using mitochondrial-targeted GS-nitroxide (JP4-039). Adult (10-12 weeks old) Fancd2(+/+), Fancd2(+/-) and Fancd2(-/-) mice (C57BL/6 background) and subgroups with orally established TC-1 epithelial cell tumors received a single fraction of 28 Gy or four daily fractions of 8 Gy to the head and neck. Subgroups received JP4-039 in F15 emulsion (F15/JP4-039; 0.4 mg/mouse), 4-amino-Tempo in F15 emulsion (F15/4-amino-Tempo; 0.2 mg/mouse) or F15 emulsion alone prior to each irradiation. Oral mucosa of Fancd2(-/-) mice showed baseline elevated RNA transcripts for Sod2, p53, p21 and Rad51 (all P < 0.0012) and suppressed levels of Nfkb and Tgfb, (all P < 0.0020) compared with Fancd2(+/+) mice. The oral mucosa in tumor-bearing mice of all genotypes showed decreased levels of p53 and elevated Tgfb and Gadd45a (P ≤ 0.0001 for all three genotypes). Intraoral F15/JP4-039, but not F15/4-amino-Tempo, modulated radiation-induced normal tissue transcript elevation, ameliorated mucosal ulceration and reduced the depletion of antioxidant stores in oral cavity tissue of all genotypes, but did not radioprotect tumors. Mitochondrial targeting makes F15/JP4-039 an effective normal tissue radioprotector for Fancd2(-/-) mice, as well as wild-type mice.

Improved hematopoiesis in GS-nitroxide (JP4-039)-treated mouse long-term bone marrow cultures and radioresistance of derived bone marrow stromal cell lines

AIM

To determine if the small-molecule radioprotector GS-nitroxide, JP4-039, improved hematopoiesis in long-term bone marrow cultures (LTBMCs), explanted marrow from in vivo drug-treated C57BL/6NTac mice was maintained in JP4-039 for 25 weeks. Hematopoietic cell production and radiobiology of derived stromal cell lines was measured.

MATERIALS AND METHODS

Groups of LTBMCs were established from mouse groups. Stromal cell lines were established from the adherent layer of JP4-039-treated and untreated control groups.

RESULTS

LTBMCs maintained in JP4-039 exhibited increased production of total non-adherent and 7-day and 14-day hematopoietic colony-forming cells. Stromal cell lines derived from JP4-039-treated cultures were radioresistant in vitro, demonstrated a distinct squamous/epithelial morphology and overexpressed Nrf2, Ctgf, Lox, Tlr1, collagen 1a, Brd3, and Brd4.

CONCLUSION

Chronic treatment of bone marrow cultures and derived stromal cell lines with JP4-039 was non-toxic, and conferred resistance to oxidative stress.

Amelioration of radiation-induced oral cavity mucositis and distant bone marrow suppression in fanconi anemia Fancd2-/- (FVB/N) mice by intraoral GS-nitroxide JP4-039

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.

Esophageal radioprotection by swallowed JP4-039/F15 in thoracic-irradiated mice with transgenic lung tumors

BACKGROUND/AIM

To determine whether Gramicidin S (GS)-nitroxide, JP4-039, esophageal radiation protection protected lung tumors in a transgenic model, LoxP-Stoop-LoxP Kristen Rat Sarcoma Viral oncogene (LSL-K-RAS) mice were administered intra-tracheal- Carbapenem-resistant Enterobacteriaceae (CRE) recombinase, bilateral lung tumors were confirmed at 11 weeks, then thoracic irradiation was delivered.

MATERIALS AND METHODS

Mice received single-fraction 15 Gy or 24 Gy to both lungs, in subgroups receiving intraesophageal administration 10 min before irradiation of JP4-039 (in F15 emulsion) tumor size reduction and survival were investigated. Mice were followed for survival, and reduction in tumor size.

RESULTS

There was no evidence of tumor radioprotection in mice receiving JP4-039/F15.

CONCLUSION

Intraesophageal radioprotective small-molecule antioxidant therapy protects normal tissue but not tumor tissue in mice with transgenic lung tumors.

Effects of the bifunctional sulfoxide MMS350, a radiation mitigator, on hematopoiesis in long-term bone marrow cultures and on radioresistance of marrow stromal cell lines

The ionizing irradiation mitigator MMS350 prolongs survival of mice treated with total-body irradiation and prevents radiation-induced pulmonary fibrosis when added to drinking water at day 100 after thoracic irradiation. The effects of MMS350 on hematopoiesis in long-term bone marrow culture and on the radiobiology of derived bone marrow stromal cell lines were tested. Long-term bone marrow cultures were established from C57BL/6NTac mice and maintained in a high-humidity incubator, with 7% CO2 and the addition of 100 μM MMS350 at the weekly media change. Over 10 weeks in culture, MMS350 had no significant effect on maintenance of hematopoietic stem cell production, or on nonadherent cells or colony-forming units of hematopoietic progenitor cells. Stromal cell lines derived from non MMS350-treated long-term cultures or control stromal cells treated with MMS350 were radioresistant in the clonogenic survival curve assay. MMS350 is a non-toxic, highly water-soluble radiation mitigator that exhibits radioprotective effects on bone marrow stromal cells.

Increased hematopoiesis in long-term bone marrow cultures and reduced irradiation-induced pulmonary fibrosis in Von Willebrand factor homologous deletion recombinant mice

AIM

We investigated whether homologous recombinant deletion of the endothelial cell-specific protein Von Willebrand factor (vWF) affected hematopoiesis in long-term bone marrow cultures, and irradiation induction of pulmonary fibrosis/organizing alveolitis.

MATERIALS AND METHODS

We established long-term bone marrow cultures from vWF(-/-) (C57BL/6 background) and vWF(+/+) littermate mice. Non-adherent cells removed weekly were tested for formation of multi-lineage hematopoietic stem cells forming colonies at 7 and 14 days in secondary semi-solid medium cultures. Irradiation fibrosis in the lungs of 20-Gy thoracic irradiated mice was quantitated and scored.

RESULTS

Hematopoiesis was increased over 20 weeks in vWF(-/-) compared to vWF(+/+) cultures in production of non-adherent cells, and cells forming colonies at 7 or 14 days in secondary semi-solid medium culture. The irradiated lungs showed no increased fibrosis.

CONCLUSION

Absence of vWF increases hematopoiesis in long-term bone marrow cultures and has a protective effect in irradiated lungs.

Improved longevity of hematopoiesis in long-term bone marrow cultures and reduced irradiation-induced pulmonary fibrosis in Toll-like receptor-4 deletion recombinant-negative mice

AIM

We measured long-term hematopoiesis in continuous bone marrow cultures derived from Toll-like receptor-4 (Tlr4(-/-))(C57BL/6J) mice.

MATERIALS AND METHODS

We measured hematopoiesis in vitro over 27 weeks in long-term bone marrow cultures from Tlr4(-/-) and control mice, and irradiation-induced pulmonary fibrosis in mice irradiated to 20 Gy to the thorax.

RESULTS

There was a significant increase in the duration of hematopoiesis in long-term bone marrow cultures from Tlr4(-/-) mice in production of total non-adherent cells and day 7 and day 14 multi-lineage colony-forming cells. The histology of bone marrow hematopoietic and stromal cell lines was indistinguishable between different mouse strains. There was no detectable late irradiation pulmonary fibrosis in Tlr4(-/-) mice.

CONCLUSION

Homozygous deletion of both alleles of Tlr4, encoding for an inflammatory mediator receptor, improves the duration of hematopoiesis in vitro and reduces irradiation-induced lung fibrosis.

Differences in irradiated lung gene transcription between fibrosis-prone C57BL/6NHsd and fibrosis-resistant C3H/HeNHsd mice

BACKGROUND/AIM

We compared pulmonary irradiation-induced whole-lung, gene transcripts over 200 days after 20 Gy thoracic irradiation in female fibrosis-prone C57BL/6NHsd mice with fibrosis-resistant C3H/HeNHsd mice.

MATERIALS AND METHODS

Lung specimens were analyzed by real time polymerase chain reaction (rt-PCR) and changes over time in representative gene transcript levels were correlated with protein levels using western blot.

RESULTS

C3H/HeNHsd mice showed a significantly longer duration of elevation of gene transcripts for stress-response genes nuclear factor kappa-light-chain-enhancer of activated B cells (Nfkb), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), transcription factor SP1 (SP1), activator protein 1 (AP1), radioprotection gene manganese superoxide dismutase (Sod2), and endothelial cell-associated genes von Willebrand factor (Vwf) and vascular endothelial growth factor (Vegf). C57BL/6NHsd mice showed acute elevation then down-regulation and a second elevation in gene transcripts for Nfkb, connective tissue growth factor (Ctgf), insulin-like growth factor-binding protein 7 (Igfbp7), tumor necrosis factor-alpha (Tnfa) Ctgf, Igfbp7, Tnfa, collagen 1a, and toll like receptor 4 (Tlr4). There were reciprocal patterns of elevation and decrease in levels of transcripts for epigenetic reader proteins bromodomain coding protein 1 (Brd1)Brd2,-3, and -4 between mouse strains.

CONCLUSION

Regulatory pathways linked to radiation pulmonary fibrosis may identify new targets for mitigators of radiation-induced fibrosis.

Radiologic differences between bone marrow stromal and hematopoietic progenitor cell lines from Fanconi Anemia (Fancd2(-/-)) mice

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.

Amelioration of radiation-induced pulmonary fibrosis by a water-soluble bifunctional sulfoxide radiation mitigator (MMS350)

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.

Radioresistance of bone marrow stromal and hematopoietic progenitor cell lines derived from Nrf2-/- homozygous deletion recombinant-negative mice

AIM

We determined whether bone marrow from Nrf2(-/-) compared with Nrf2(+/+) mice differed in response to the oxidative stress of continuous marrow culture, and in radiosensitivity of derived stromal and interleukin-3 (IL-3)-dependent hematopoietic progenitor cells.

MATERIALS AND METHODS

Hematopoiesis longevity in Nrf2(-/-) was compared with Nrf2(+/+) mice in long-term bone marrow cultures. Clonogenic irradiation survival curves were performed on derived cell lines. Total antioxidant capacity at baseline in nonirradiated cells and at 24 hours after 5 Gy and 10 Gy irradiation was quantitated using an antioxidant reductive capacity assay.

RESULTS

Long-term cultures of bone marrow from Nrf2(-/-) compared to Nrf2(+/+) mice demonstrated equivalent longevity of production of total cells and hematopoietic progenitor cells forming multi-lineage hematopoietic colonies over 26 weeks in culture. Both bone marrow stromal cell lines and Il-3-dependent hematopoietic progenitor cell lines derived from Nrf2(-/-) mouse marrow cultures were radioresistant compared to Nrf2(+/+)-derived cell lines. Both DNA repair assay and total antioxidant capacity assay showed no defect in Nrf2(-/-) compared to Nrf2(+/+) stromal cells and IL-3-dependent cells.

CONCLUSION

The absence of a functional Nrf2 gene product does not alter cellular interactions in continuous marrow culture, nor response to dsDNA damage repair and antioxidant response. However, lack of the Nrf2 gene does confer radioresistance on marrow stromal and hematopoietic cells.

Conditional radioresistance of Tet-inducible manganese superoxide dismutase bone marrow stromal cell lines

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.

Increased longevity of hematopoiesis in continuous marrow cultures and radiation resistance of marrow stromal and hematopoietic progenitor cells from caspase-1 homozygous recombinant-negative (knockout) mice

AIM

We determined whether absence of caspase-1 altered the stress response of hematopoietic and bone marrow stromal cells in vitro.

MATERIALS AND METHODS

Long-term bone marrow cultures from caspase-1 -/- and control caspase-1 +/+ mice were established and the derived bone marrow stromal and interleukin-3 (Il-3)-dependent hematopoietic progenitor cell lines were evaluated for radiosensitivity.

RESULTS

Long-term bone marrow cultures from caspase-1 -/- mice generated hematopoietic cells for over 30 weeks in vitro, significantly longer than controls did (p=0.0018). Bone marrow stromal (mesenchymal stem cell) and Il-3-dependent hematopoietic progenitor cell lines from caspase-1-/- marrow cultures compared to caspase-1 +/+ were radioresistant (p=0.0486 and p=0.0235 respectively). Total-body irradiated caspase-1 -/- mice were not significantly radioresistant compared to controls (p=0.6542).

CONCLUSION

Caspase-1 deletion increases hematopoiesis and radioresistance of bone marrow cells in vitro.

Effects of thoracic irradiation on pulmonary endothelial compared to alveolar type-II cells in fibrosis-prone C57BL/6NTac mice

BACKGROUND/AIM

Thoracic irradiation results in an acute inflammatory response, latent period, and late fibrosis. Little is known about the mechanisms involved in triggering late radiation fibrosis.

MATERIALS AND METHODS

Thoracic irradiated fibrosis prone C57BL/6NTac mice were followed for detectable mRNA transcripts in isolated lung cells and micro-RNA in whole-tissues, and the effect of administration of water-soluble oxetanyl sulfoxide MMS350 was studied. Marrow stromal cell motility in medium from fibrotic-phase explanted pulmonary endothelial and alveolar type-II cells was measured.

RESULTS

RNA and micro-RNA expression in lung correlated with fibrosis. MMS350 reduced pro-fibrotic gene expression in both endothelial and alveolar type-II cells in irradiated mice. Conditioned medium from irradiated cells did not alter cell motility in vitro.

CONCLUSION

These studies should facilitate identification of potential new drug targets for ameliorating irradiation-induced pulmonary fibrosis.

Abstract 426: In-field head and neck irradiation radiosensitivity of FancD2-/- mice and bystander effect reduction of distant bone marrow hematopoietic progenitor cells

Background: Irradiation induced normal tissue toxicity limits effective radiotherapy of individuals with DNA repair defects including Fanconi anemia. We quantitated in-field head and neck tissue response in irradiated Fanconi anemia knockout mice, FancD2-/-, compared to wild type, FancD2+/+ & heterozygous FancD2+/- mice. We also assessed bystander effect of head and neck irradiation on distant bone marrow hematopoietic progenitor cell numbers.

Method: Adult 10-12wk old FevB background FancD2+/+, +/- and -/- mice were irradiated to the head & neck to 24Gy, 26Gy, 28Gy or 30Gy (n=3) shielding all tissue below the cervical spine. On day 2 or 5 post irradiation, mice were sacrificed and tongue tissue and one femur excised for histopathology. Bone marrow of the contralateral femur was plated for colony assay. Colony forming unit-granulocyte macrophage (CFU-GM), burst forming unit erythroid (BFU-E), and colony forming unit-granulocyte-erythroid-megakaryocyte-monocyte (CFU-GEMM) numbers were counted & each genotype compared to its unirradiated control. H&E stained tongue sections were scored for oral mucositis.

Results: Both FancD2-/- & FancD2+/- mice were radiosensitive to lower doses compared to FancD2+/+ mice measured as percent ulceration of the squamous layer of tongue epithelium 5 days post irradiation. Both FancD2+/- and FancD2-/- mice had significantly higher ulceration after 26Gy (52.8±6.5%, p=0.0014 and and 59.4±3.4%, p=0.0001, respectively) compared to wild type FancD2+/+ (21.7±4.7%). At the lower dose of 24Gy, FancD2+/- and -/- had higher percent ulceration (p=0.0001 and p=0.0003) than FancD2+/+ mice irradiated to even higher doses of 26Gy and 28Gy. FancD2+/+ mice had high levels of ulceration after 28Gy (p=0.2355). While there was no difference in distant bone marrow cellularity between irradiated groups, both FancD2-/- & FancD2+/- showed bystander reduction in colony forming cells. CFU-GM were significantly reduced at 2 days after 26Gy in FancD2+/- mice compared to unirradiated controls (p=0.007). FancD2 -/- mice had decreased BFU-E after 24Gy (p=0.009) & CFU-GEMM after 26Gy (p=0.048) and reduced BFU-E numbers after 26Gy (p=0.031). FancD2-/- mice had significantly less CFU-GM after either 26Gy or 28Gy (p=0.017 and p=0.028, respectively). FancD2-/- & +/- mice, at 5 days after 26Gy, had less CFU-GM (p=0.001 and 0.012, respectively) and CFU-GEMM (p=0.014 and p=0.004, respectively) compared to unirradiated controls. There was no reduction in CFU-GM, BFU-E or CFU-GEMM in wild type FancD2+/+mice after 28 or 30Gy.

Conclusion: Biallelic or monoallelic loss of the FA gene renders mice radiosensitive to in-field head and neck irradiation compared to wild type mice, and is accompanied by a distant femur marrow bystander effect including reduction of colony forming unit.

Supported by NIAID U19-A 1068021 and FA Research Foundation

Citation Format: Hebist Berhane, Julie Goff, Ronny Kalash, Michael W. Epperly, Tracy Dixon, Donna Shields, Darcy Franicola, Joel S. Greenberger. In-field head and neck irradiation radiosensitivity of FancD2-/- mice and bystander effect reduction of distant bone marrow hematopoietic progenitor cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 426. doi:10.1158/1538-7445.AM2013-426

Ionizing irradiation protection and mitigation of murine cells by carbamazepine is p53 and autophagy independent

BACKGROUND

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

Carbamazepine is a murine radiation protector and mitigator.

Repopulation of the irradiation damaged lung with bone marrow-derived cells

AIM

The effect of lung irradiation on reduction of lung stem cells and repopulation with bone marrow-derived cells was measured.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

Bone marrow progenitor cells may not participate in the repopulation of the lung following irradiation.

GS-nitroxide (JP4-039)-mediated radioprotection of human Fanconi anemia cell lines

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.

Two strategies for the development of mitochondrion-targeted small molecule radiation damage mitigators

PURPOSE

To evaluate the effectiveness of mitigation of acute ionizing radiation damage by mitochondrion-targeted small molecules.

METHODS AND MATERIALS

We evaluated the ability of nitroxide-linked alkene peptide isostere JP4-039, the nitric oxide synthase inhibitor-linked alkene peptide esostere MCF201-89, and the p53/mdm2/mdm4 protein complex inhibitor BEB55 to mitigate radiation effects by clonogenic survival curves with the murine hematopoietic progenitor cell line 32D cl 3 and the human bone marrow stromal (KM101) and pulmonary epithelial (IB3) cell lines. The p53-dependent mechanism of action was tested with p53(+/+) and p53(-/-) murine bone marrow stromal cell lines. C57BL/6 NHsd female mice were injected i.p. with JP4-039, MCF201-89, or BEB55 individually or in combination, after receiving 9.5 Gy total body irradiation (TBI).

RESULTS

Each drug, JP4-039, MCF201-89, or BEB55, individually or as a mixture of all three compounds increased the survival of 32D cl 3 (p = 0.0021, p = 0.0011, p = 0.0038, and p = 0.0073, respectively) and IB3 cells (p = 0.0193, p = 0.0452, p = 0.0017, and p = 0.0019, respectively) significantly relative to that of control irradiated cells. KM101 cells were protected by individual drugs (p = 0.0007, p = 0.0235, p = 0.0044, respectively). JP4-039 and MCF201-89 increased irradiation survival of both p53(+/+) (p = 0.0396 and p = 0.0071, respectively) and p53(-/-) cells (p = 0.0007 and p = 0.0188, respectively), while BEB55 was ineffective with p53(-/-) cells. Drugs administered individually or as a mixtures of all three after TBI significantly increased mouse survival (p = 0.0234, 0.0009, 0.0052, and 0.0167, respectively).

CONCLUSION

Mitochondrial targeting of small molecule radiation mitigators decreases irradiation-induced cell death in vitro and prolongs survival of lethally irradiated mice.

Radiobiologic effects of GS-nitroxide (JP4-039) on the hematopoietic syndrome

BACKGROUND/AIM

Total-body irradiation (TBI) doses in the range of 2-8 Gy are associated with a drop in peripheral blood counts, decreased bone marrow cellularity, and hematopoietic syndrome. Radiation mitigators must be safe for individuals likely to recover spontaneously.

MATERIALS AND METHODS

Female C57BL/6HNsd mice exposed to 9.0 and 9.15 Gy TBI, received intraperitoneal (10 mg/kg) JP4-039, a novel radiation mitigator, 24 hours after irradiation and were followed for hematopoietic recovery.

RESULTS

Irradiated mice showed reduced peripheral blood lymphocytes and neutrophils and bone marrow cellularity at day 5. Serum electrolytes, liver and renal function tests showed no deleterious effect of JP4-039-after irradiation, and no reduction in survival compared to irradiated controls. Marrow recovery measured as cellularity, and hematopoietic colony-forming cells including primitive granulocyte-erythroid-megakaryocyte-monocytes (GEMM), reached pre-irradiation levels by day 30 in JP4-039 treated groups. Mice receiving single or multiple administrations of JP4-039 showed an early return of CFU-GEMM.

CONCLUSION

JP4-039 (GS-Nitroxide) is a safe radiation mitigator in mice warranting studies in larger animals and potentially a Phase I Clinical Trial.

Abstract 2503: Distinct radiosensitivities of human FancG-/- and FancD2-/- cell lines

Background: Fanconi Anemia is an autosomal recessive disorder marked by a dysfunction of DNA repair, an increased sensitivity to DNA crosslinking agents, and some patients poorly tolerating ionizing irradiation. We determined the radiosensitivity of two Fanconi patient cell lines and we determined if the nitroxide radioprotector Tempo or a novel mitochondrial targeted nitroxide JP4-039 could alter their radiosensitivity.

Materials and Methods: Fanconi patient derived fibroblastic cell lines, PD326 and PD20F, and their respective transgene restored cell lines FancG and FancD2 were irradiated to doses ranging from 0 to 8 Gy in the presence or absence of Tempo or JP4-039 (10 µm), plated, and colonies greater than 50 cells were counted eight days later.

Results: The PD20F cell line was more radiosensitive compared to the restored FancD2 cell line (n = 1.6 + 0.2 and 10.7 + 3.1, respectively, p = 0.0423). In contrast the PD326 cell line was more radioresistant than its restored FancG cell line as seen by an increased shoulder on the survival curve (n = 8.1 + 1.4 and 2.2 + 0.3, respectively, p = 0.0174). JP4-039 but not Tempo increased radioresistance in the PD326 (n = 15.7 + 2.5, p = 0.0373), and FancG cell lines (10.2 + 2.1, p = 0.0151).

Conclusions: The human Fanconi Anemia cell line PD326 is radioresistant when compared to its transgene restored FancG cell line, and this radioresistance is increased by treatment with the mitochondrial targeted nitroxide JP4-039. In contrast, PD20F is more radiosensitive when compared to its transgene restored FancD2 cell line. Testing the efficacy of JP4-039 and Tempo on mitigating the effects of mitomycin C treatment is being evaluated.

Supported by 2U19A1068021-06

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2503. doi:10.1158/1538-7445.AM2011-2503

Abstract 2502: Swallowed small molecule GS-nitroxide, JP-4-039, protects the irradiated esophagus

Irradiation induced esophagitis is a dose limiting factor in the treatment of lung cancer, and limits irradiation dose escalation. Intraesophageal manganese superoxide dismutase plasmid liposomes has been shown to protect against irradiation esophagitis (Tarhini, et.al. Human Gene Therapy, in press). A new small molecule drug recently has shown irradiation protection and mitigation in vitro. The new drug (JP4-039) is a nitroxide attached to a mitochondrial targeting sequence. Drug was delivered to the top of the esophagus and the mouse swallowed the F15 formulation, consisting of soy PC: Tween-80: L-glutamyl dioleylamide (4:1:1 w/w) and 8 mg/ml of JP4-039 in PBS. C57BL/6NHsd mice swallowed 100 µl water followed by 100 µl F15-JP4-039 (0.4 mg/mouse) ten minutes before 28 Gy to the upper body. F15-JP4-039 resulted in a significant increase in survival compared to irradiated controls. F15-JP4-039 produced a 30 day survival of 75% compared to 30% for irradiation control (p = 0.0315). The JP4-039 nitroxide signal, detected by EPR, allowed demonstration that drug was in whole esophagus and in the esophageal stem cells. F15-JP4-039 intraorally treated mice were sacrificed at 10 min, 30 min, 1 hr or 5 hr after swallowing the F15-JP4-039, esophagus removed, single cell suspensions made, frozen, and analyzed by EPR. At 10 min, 2971.3 fmoles of JP4-039/million cells were detected, and still detected out to 5 hours, 1081 fmoles/million cells, after irradiation. Sorted side population cells (SP), enriched for stem cells, and nonside population cells (NSP) isolated by flow cytometer were analyzed at 10 min after swallow, by EPR for JP4-039 uptake. The SP cells had 3666.7 fmoles per million cells and the NSP cells had 73.7 fmoles nitroxide per million cells demonstrating that drug had reached stem cells. Thus, intraesophageal administration of small molecule antioxidant GS-nitroxide reduces murine radiation esophagitis, and may be a valuable translational radiation protector to ameliorate clinical esophagitis in lung cancer patients.

Supported by 2U19A1068021-06 and RO1-CA83876-06

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2502. doi:10.1158/1538-7445.AM2011-2502