Radiation-induced hematopoietic myelosuppression and genotoxicity get significantly countered by active principles of Podophyllum hexandrum: A study in strain 'A' mice.

PURPOSE: To investigate the protective role of a novel formulation, prepared by a combination of three active principles isolated from Podophyllum hexandrum (G-002M), against radiation- mediated hematopoietic suppression and cytogenetic aberrations in lethally irradiated mice. MATERIALS AND METHODS: G-002M, a combination of podophyllotoxin, podophyllotoxin-ß-D glucoside and rutin, was administered intramuscularly in mice (- 1 h) to radiation (9 Gy) exposure. The animals were autopsied at different time intervals for further studies. RESULTS: Loss of bone marrow progenitor cells, altered myeloid/erythroid ratio, serum erythropoietin and pancytopenia in irradiated mice was found significantly (p < 0.001) ameliorated in G-002M pre-administered mice within 30 d. Bcl-2 (B-cell lymphoma 2) and BAX (Bcl-2-associated X) protein expression was also positively (p < 0.001) countered in these mice. Chromosomal aberrations in 30 d were found remarkably (p < 0.001) reduced in marrow of G-002M pretreated mice. Accelerated antioxidants, reduced DNA damage, stimulated lymphocyte proliferation and minimal cellular atrophy in spleen were some of the other key features observed in G-002M administered mice. CONCLUSIONS: Reduction in hematopoietic aplasia and chromosomal aberrations, besides, early recovery in bone marrow and spleen of G-002M pretreated mice, could be attributed to its free radical scavenging, DNA protecting and apoptotic proteins modulating ability against radiation.

Kinetics of neutrophils in mice exposed to radiation and/or granulocyte colony-stimulating factor treatment.

Astronauts have the potential to develop the hematopoietic syndrome as a result of exposure to radiation from a solar particle event (SPE) during exploration class missions. This syndrome is characterized by a reduction in the number of circulating blood cells (cytopenias). In the present study the effects of SPE-like proton and γ radiation on the kinetics of circulating neutrophils were evaluated during a one-month time period using mice as a model system. The results revealed that exposure to a 2 Gy dose of either SPE-like proton or γ radiation significantly decreased the number of circulating neutrophils, with two nadirs observed on day 4 and day 16 postirradiation. Low circulating neutrophil count (neutropenia) is particularly important because it can increase the risk of astronauts developing infections, which can compromise the success of the mission. Thus, two granulocyte colony-stimulating factors (G-CSFs), filgrastim and pegfilgrastim were evaluated as countermeasures for this endpoint. Both forms of G-CSF significantly increased neutrophil counts in irradiated mice, however, the effect of pegfilgrastim was more potent and lasted longer than filgrastim. Using the expression of CD11b, CD18 and the production of reactive oxygen species (ROS) as markers of neutrophil activation, it was determined that the neutrophils in the irradiated mice treated with pegfilgrastim were physiologically active. Thus, these results suggest that pegfilgrastim could be a potential countermeasure for the reduced number of circulating neutrophils in irradiated animals.

[Therapeutic effects and prognostic factors for the limited-stage small cell lung cancer treated with multidisciplinary therapy].

OBJECTIVE: To study the differences of objective response rate (ORR), side effects and survival among patients with limited-stage small cell lung cancer (LD-SCLC), who received concurrent chemoradiotherapy, sequential chemoradiotherapy or chemotherapy alone, and to analyze the influencing factors on their survival. METHODS: One hundred and sixty-six patients diagnosed as LD-SCLC in Peking Union Medical College Hospital from January 2000 to December 2009 were included in this study. The differences of objective response rates, side effects and survival rates were analyzed by χ2 test. Kaplan-Meier test was used to calculate the overall survival (OS) and progress-free survival (PFS). Cox regression was used to detect the influencing factors on survival time of the patients. RESULTS: The patients were divided into three groups: concurrent chemoradiotherapy (49 cases), sequential chemoradiotherapy (62 cases) and chemotherapy alone (55 cases). The chemotherapy was based on CE/EP regimen, with an average cycle of 5.2. Radiotherapy was of a common or 3-dimensional conformal technology, for regular segmentation irradiation with an average dose of 49.6 Gy. The total ORR was 73.4%, OS and PFS were 22.9 months and 10.8 months, 1, 3, 5-year survival rates were 82.7%, 31.8%, 18.6%, respectively. For the concurrent group, sequential group and chemotherapy alone group, the ORR was 89.4%, 67.2% and 66.0%, respectively. Compared the chemotherapy alone group and concurrent group with the sequential group, there were significant differences (P<0.05). For the concurrent group, sequential group and chemotherapy alone group, the median OS was 29.7 months, 22.6 months, and 19.5 months; the median PFS was 12.7 months, 10.8 months, and 9.8 months, respectively, with a non-significant difference between each two groups (P>0.05). For the concurrent group, sequential group and chemotherapy alone group, the 1-year survival rates were 91.1%, 86.3%, and 65.6%, the 3-year survival rates were 44.2%, 28.3% and 22.8%, and the 5-year survival rates were 24.2%, 21.4% and 11.1%, respectively, with significant differences among them (P<0.05). The major side effects were myelosuppression, gastrointestinal reactions, radiation pneumonia and radiation esophagitis. For the concurrent group, sequential group and chemotherapy alone group, the incidence of myelosuppression were 84.4%, 76.8% and 60.0%, respectively, with a significant difference (P=0.008) between the concurrent group and chemotherapy alone group. For the concurrent group and sequential group, the incidences of radiation pneumonia were 22.2% and 22.9%, with a non-significant difference (P=0.940). The incidences of radiation esophagitis were 47.2% and 16.7%, respectively, with a significant difference (P=0.002). Multivariate analysis showed that OS was significantly associated with gender (P=0.018) and ECOG score (P=0.009), and PFS was significantly associated with gender (P=0.050). CONCLUSIONS: For LD-SCLC, concurrent chemoradiotherapy can significantly increase the objective response rate. Concurrent chemoradiotherapy and sequential chemoradiotherapy compared with chemotherapy alone can extend survival, and concurrent chemoradiotherapy is better, but the differences among the three regimens are not significant. Gender and ECOG score are important influencing factors of survival.

Stimulatory action of cyclooxygenase inhibitors on hematopoiesis: a review.

The presented review summarizes experimental data obtained with a mouse model when investigating the relationship between inhibition of prostaglandin production and hematopoiesis. While prostaglandin E2 acts in a negative feedback control of myelopoiesis, inhibition of cyclooxygenases, responsible for its production, shifts the feedback to positive control. Based on these relationships, agents inhibiting cyclo-oxygenases, known as non-steroidal anti-inflammatory drugs (NSAIDs), can activate hematopoiesis and be protective or curative under myelosuppressive states. The effectiveness of therapeutic use of NSAIDs in these situations is expressive especially under the selective inhibition of cyclooxygenase-2 (COX-2), when undesirable side effects of cyclooxygenase-1 inhibition, like gastrointestinal damage, are absent. The effects of the clinically approved selective COX-2 inhibitor, meloxicam, were investigated and demonstrated significant hematopoiesis-stimulating and survival-enhancing actions of this drug in sublethally or lethally γ-irradiated mice. These effects were connected with the ability of meloxicam to increase serum levels of the granulocyte colony-stimulating factor. It can be inferred from these findings that selective COX-2 inhibitors might find their use in the treatment of myelosuppressions of various etiologies.

Ultraviolet irradiation of mice reduces the competency of bone marrow-derived CD11c+ cells via an indomethacin-inhibitable pathway.

Direct UV irradiation of dendritic cells and Langerhans cells reduces their Ag presenting ability. However, the effects of UV on CD11c(+) cells located distally to the point of irradiation are poorly understood. Three days after UV irradiation (8 kJ/m(2)) of BALB/c mice, bone marrow cells were isolated and cultured for 7 d with IL-4 and GM-CSF for the propagation of CD11c(+) cells. Bone marrow-derived CD11c(+) cells from UV-irradiated or nonirradiated mice were loaded with dinitrobenzene sulfonic acid and injected into the ear pinnas of naive BALB/c mice. After 7 d, the ears were painted with 2,4-dinitro-1-fluorobenzene and the ear swelling determined 24 h later. A reduced contact hypersensitivity response was found in mice injected with CD11c(+) cells from the UV-irradiated animals compared with those injected with cells from the nonirradiated animals. Further, a long-lasting suppression of the memory response to 2,4-dinitro-1-fluorobenzene was created. This suppressed response corresponded to increased IL-10 and PGE(2) secretion by freshly isolated bone marrow cells from UV-irradiated mice, and to increased myelopoiesis. The reduction in competence of bone marrow-derived CD11c(+) cells from UV-irradiated mice was not due to delayed maturation, as it was maintained upon LPS exposure prior to CD11c(+) cell purification. The UV-induced effect was reversed by the administration of indomethacin to mice prior to UV irradiation and could be reproduced by s.c. PGE(2). These results show that UV irradiation of mice can affect the function of bone marrow-derived CD11c(+) cells via a mechanism inhibitable by indomethacin; this pathway is likely to contribute to systemic UV-induced immunosuppression.

A distinctive DNA damage response in human hematopoietic stem cells reveals an apoptosis-independent role for p53 in self-renewal.

Highly regenerative tissues such as blood must possess effective DNA damage responses (DDR) that balance long-term regeneration with protection from leukemogenesis. Hematopoietic stem cells (HSCs) sustain life-long blood production, yet their response to DNA damage remains largely unexplored. We report that human HSCs exhibit delayed DNA double-strand break rejoining, persistent gammaH2AX foci, and enhanced p53- and ASPP1-dependent apoptosis after gamma-radiation compared to progenitors. p53 inactivation or Bcl-2 overexpression reduced radiation-induced apoptosis and preserved in vivo repopulating HSC function. Despite similar protection from irradiation-induced apoptosis, only Bcl-2-overexpressing HSCs showed higher self-renewal capacity, establishing that intact p53 positively regulates self-renewal independently from apoptosis. The reduced self-renewal of HSCs with inactivated p53 was associated with increased spontaneous gammaH2AX foci in secondary transplants of HSCs. Our data reveal distinct physiological roles of p53 that together ensure optimal HSC function: apoptosis regulation and prevention of gammaH2AX foci accumulation upon HSC self-renewal.

Scorpion venom peptides accelerate hematopoietic recovery of myelosuppression in irradiated mice.

Sublethally irradiated mice were administered with scorpion venom peptides (SVP) or with PBS in the saline control group, 3 days before and 7 consecutive days after irradiation. Hematopoietic recovery was assessed by bone marrow (BM) cell proliferation index (PI) and colony forming unit-granulocyte/macrophage (CFU-GM), spleen weight index (SI) and thymus weight index (TI), colony-forming unit-spleen (CFU-S) and peripheral leukocyte counts. In addition, IL-1alpha and SCF levels in BM, IL-6 and GM-CSF levels in serum were determined. In SVP treated groups, PI was improved dramatically versus control mice on day 22 after irradiation. The number of CFU-GM colonies in all SVP treated groups was higher than the control groups. The difference of the number of CFU-GM colonies between SVPV group (0.2 mg/kg) and the control was significant on day 5 and 10 after irradiation (p < 0.05). SVPIV (0.2 mg/kg) could activate the CFU-S formation on day 10 after irradiation. SI was in peak value on day 15 after irradiation in all groups and the SI value of SVPV treated group was higher than control group (p < 0.05). Our results suggest that SVP may be valuable natural peptides that relieve myelosuppression caused by radiation. The effect of SVP accelerating the hematopoietic recovery was potentially through a mechanism of stimulating the release of cytokines.

Sustained telomere erosion due to increased stem cell turnover during triple autologous hematopoietic stem cell transplantation.

Telomeres cap chromosomal ends and are shortened throughout a lifetime. Additional telomere erosion has been documented during conventional chemotherapy or hematopoietic stem cell transplantation. Previous studies of stem cell transplantation reported variable amounts of telomere shortening with inconsistent results regarding the persistence of telomere shortening. Here we have prospectively studied telomere length and proliferation kinetics of hematopoietic cells in aggressive non-Hodgkin lymphoma patients who underwent a four-course high-dose chemotherapy protocol combined with triple autologous stem cell transplantation. We observed sustained telomere shortening in hematopoietic cells after triple stem cell transplantation with prolonged stem cell replication during the first year after stem cell transplantation.

Slug antagonizes p53-mediated apoptosis of hematopoietic progenitors by repressing puma.

In response to DNA damage, the p53 tumor suppressor can elicit either apoptosis or cell-cycle arrest and repair, but how this critical decision is made in specific cell types remains largely undefined. We investigated the mechanism by which the transcriptional repressor Slug specifically rescues hematopoietic progenitor cells from lethal doses of gamma radiation. We show that Slug is transcriptionally induced by p53 upon irradiation and then protects the damaged cell from apoptosis by directly repressing p53-mediated transcription of puma, a key BH3-only antagonist of the antiapoptotic Bcl-2 proteins. We established the physiologic significance of Slug-mediated repression of puma by demonstrating that mice deficient in both genes survive doses of total-body irradiation that lethally deplete hematopoietic progenitor populations in mice lacking only slug. Thus, Slug functions downstream of p53 in developing blood cells as a critical switch that prevents their apoptosis by antagonizing the trans-activation of puma by p53.

Ex vivo activated immune cells promote survival and stimulate multilineage hematopoietic recovery in myelosuppressed mice.

Recovery of multilineage hematopoiesis from severe myelosuppression due to chemotherapy and radiotherapy remains a clinical problem. The authors have developed a simple immunotherapy to treat this disease in a mouse model. Syngeneic spleen cells or xenogeneic human peripheral mononuclear cells were cultured ex vivo with a combination of IL-2 at 500 IU/mL, GM-CSF at 200 U/mL, and calcium ionophore A23187 at 100 ng/mL for 2 days and injected intravenously into mice that had previously received a lethal dose of carboplatin and radiation. The therapy was highly effective: a single injection of activated cells enhanced survival and simulated multilineage recovery of hematopoiesis. Ex vivo activated immune cells produced multiple cytokines, including several hematopoietic growth factors. Adherent cells were found to be more potent than nonadherent cells in promoting survival, and the therapy alone was capable of mobilizing peripheral blood stem cells in normal mice.

A novel polysaccharide of black soybean promotes myelopoiesis and reconstitutes bone marrow after 5-flurouracil- and irradiation-induced myelosuppression.

The aim of this study was to investigate the promotion of myelopoiesis by an active polysaccharide of black soybean (PSBS). Murine spleen cells were collected from ICR mice and conditioned media (SCM) was prepared by incubating these cells without PSBS (normal-SCM) or with PSBS in concentrations ranging from 12.5 to 100 microg/ml (PSBS-SCM). Murine bone marrow cells were treated with PSBS alone or SCM to induce the formation of colonies, including CFU-GM, CFU-GEMM, BFU-E and HPP-CFC. The concentrations of six hematopoietic growth factors contained in SCM were measured using enzyme-linked immunoassay. In the live animal experiment, PSBS was administered orally to total body-irradiated (TBI) and 5-fluorouracil (5-FU)-treated mice to assess the reconstitution of bone marrow after myelosuppression. PSBS-SCM stimulated CFU-GM, CFU-GEMM, BFU-E and HPP-CFC colony formation with 45.0, 5.0, 6.2 and 6.6-fold increases, respectively. However, neither PSBS alone nor normal-SCM had such a colony-stimulating effect. In PSBS-SCM, the levels of IL-6, IL-17, G-CSF and GM-CSF were markedly increased, but not those of IL-3 and SCF. Oral administration of PSBS in mice not only restored the leukocyte counts reduced by TBI and 5-FU treatment but also enhanced CFU-GM colony formation of bone marrow cells without a significant change in body weight. We conclude that PSBS promotes myelopoiesis activity in the bone marrow, stimulates production of various hematopoietic growth factors from spleen cells, and reconstitutes bone marrow that has been myelosuppressed by irradiation and 5-FU.

Granulocyte/macrophage colony-stimulating factor and accessory cells modulate radioprotection by purified hematopoietic cells.

Granulocyte/macrophage colony-stimulating factor (GM-CSF) promotes the survival, proliferation, and differentiation of myeloid lineage cells and regulates chemotaxis and adhesion. However, mice in which the genes encoding GM-CSF (Gmcsf) or the beta common subunit of the GM-CSF receptor (betac) are inactivated display normal steady-state hematopoiesis. Here, we show that host GM-CSF signaling strongly modulates the ability of donor hematopoietic cells to radioprotect lethally irradiated mice. Although bone marrow mononuclear cells efficiently rescue Gmcsf mutant recipients, fetal liver cells and Sca1(+) lin(-/dim) marrow cells are markedly impaired. This defect is partially attributable to accessory cells that are more prevalent in bone marrow. In contrast, Gmcsf-deficient hematopoietic stem cells demonstrate normal proliferative potentials. Short-term survival is also impaired in irradiated betac mutant recipients transplanted with fetal liver or bone marrow. These data demonstrate a nonredundant function of GM-CSF in radioprotection by donor hematopoietic cells that may prove relevant in clinical transplantation.