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

Abstract

Abstract. Background/Aim: Total-body Bone marrow transplantation is an established therapy for Fanconi anemia (FA) patients (1-4) that can result in a significant improvement in survival following donor bone marrow engraftment (4). Critical to the success of marrow engraftment has been the application of chemotherapeutic agents as a preparatory regimen for marrow transplant that minimize toxicity to the host (3).FA patients have previously been demonstrated to have a hyperactive TGF-β response pathway (5), which may be a major cause of their initial marrow failure leading to anemia, as well as their sensitivity to the regimens used to prepare for bone marrow transplantation (1-4, 6-9). FA patients are also susceptible to late post-transplant induction of leukemia and solid tumors (7-15). DNA cross-linking agents such as mitomycin-C (14), other chemotherapeutic agents and irradiation induce DNA double strand breaks and must be delivered very cautiously to FA patients. The TGF-β signaling pathway alters both baseline and post-marrow transplant hematopoiesis in FA patients and in FA animal models (16-23). The chemotherapy drug, fludarabine (6,(24)(25), has facilitated bone marrow engraftment in FA patients, who are fragile in responsiveness to agents used in preparation for marrow transplantation (1-4, 6-9). We hypothesized that agents, which ameliorate the toxicity of total-body irradiation and/or chemotherapy drugs that may reduce the induction of TGF-β (26-33) might decrease toxicity and improve engraftment in FA patient transplant recipients. Furthermore, improvement in survival of patients with FA (4) might be achieved by reduction in the toxicity of marrow transplant.In this study, FANCD2 -/-mice were used for in vitro testing of the effects of two potential modulators (JP4-039 and MMS350) of the toxicity of irradiation or each of three chemotherapeutic drugs on TGF-β induction in hematopoietic progenitor cells. FANCD2 -/-mouse marrow hematopoietic progenitors in vitro and stromal cell lines derived from the hematopoietic microenvironment (34) were used for TGF-β induction by irradiation and chemotherapy drugs. We also tested the effect of JP4-039 and MMS350 on TGF-β induction in plasma of TBI irradiated or drug-treated FANCD2 -/-(C57BL/6 background) mice. 159

Amelioration of Head and Neck Radiation-Induced Mucositis and Distant Marrow Suppression in Fanca–/– and Fancg–/– Mice by Intraoral Administration of GS-Nitroxide (JP4-039)

“…An assay for abscopal suppression of the true primitive marrow stem cell population would require the competitive repopulation assay (35), which was not done in the current studies. The current data suggest that the radiosensitivity of cells of the bone marrow microenvironment (bone marrow stromal cells, mesenchymal stem cells) can overcome the radioresistance of hematopoietic progenitor cells (13, 14, 34). An indirect effect of radiosensitive stromal cells on the hematopoietic cells of FA patients may explain the relative ease of engraftment of donor “normal” hematopoietic progenitor cells into FA patients, since donor cells do not display the same sensitivity to TGF-β (23, 34).…”

Bone Marrow Mesenchymal Stem Cells Carrying FANCD2 Mutation Differ from the Other Fanconi Anemia Complementation Groups in Terms of TGF-β1 Production

“…Effects of TGF-β signaling in BM are wide ranged, from controlling HSC cell fate to remodeling of the BM niche [18,19]. Autocrine signaling of TGF-β in HSC is apparent [20] and very recent in vivo studies in mice have begun to unveil the role of TGF-β in Fanconi anemia BM [17,21]. The paracrine influence from BM-MSCs, as part of the BM microenvironment, still needs to be elucidated to understand BMF in Fanconi anemia.…”

Fludarabine modulates expression of type VII collagen during haematopoietic stem cell transplantation for recessive dystrophic epidermolysis bullosa*

“…Beyond ERK and AKT, fludarabine has also been shown to regulate other pathways associated with COL7A1 regulation, including the TGF‐β pathway 28 . To determine if TGF‐β signalling was involved in regulating COL7A1 expression, we used a TGF‐β signalling inhibitor (SIS3) in combination with fludarabine.…”

“…Beyond ERK and AKT, fludarabine has also been shown to regulate other pathways associated with COL7A1 regulation, including the TGF-b pathway. 28 To determine if TGF-b signalling was involved in regulating COL7A1 expression, we used a TGF-b signalling inhibitor (SIS3) in combination with fludarabine. Fibroblasts that were pretreated with the TGF-b inhibitor and that sustained treatment with the inhibitor throughout fludarabine exposure showed less of an increase in COL7A1 expression than fibroblasts treated with fludarabine alone (Figure 4a, b).…”