Leukemia Stem/Progenitor Cells From AML Patients Treated With The Multi-Kinase Inhibitor TG02 Demonstrate Increased Proliferation and Are Sensitized To Chemotherapeutic Agents

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3892-3892 ◽  
Author(s):  
Monica L. Guzman ◽  
Wen Xie ◽  
Jeanne P. De Leon ◽  
Francis Burrows ◽  
Eric J. Feldman ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Peripheral Blood ◽  
Colony Formation ◽  
Kinase Inhibitor ◽  
Chemotherapeutic Agents ◽  
Positive Staining ◽  
Annual Meeting Abstract ◽  
The Impact

Abstract TG02 is a multi-kinase inhibitor that targets cyclin-dependent kinases (CDKs), ERK5, JAK2, and Flt3. In vitro studies of TG02 have shown robust induction of apoptosis in both acute myeloid leukemia (AML) cell lines and primary cells (Goh et al, 2011). Leukemia stem cells (LSCs) comprise a largely quiescent, highly chemotherapy-resistant cell population and are believed to initiate and maintain AML, as well as contribute to its poor prognosis. Thus, we sought to investigate the impact of TG02 on LSCs collected from patients with relapsed/refractory AML enrolled in a phase I dose escalation trial. Patients ≥ 18 years with advanced hematological malignancies or newly diagnosed AML pts ≥ 65 years unfit for intensive therapy were enrolled onto daily (A) and intermittent (B, 5 days on 2 days off X 2 weeks) schedules in 28-day cycles. Pts had acceptable organ function and ECOG PS 0-2. Dose levels were 10 - 70 mg on arm A and 30 - 150 mg on arm B. We evaluated immunophenotypically defined leukemia stem and progenitor cells (LSPCs) by flow cytometry, cell cycle status and colony forming assays. A total of 16 patients were evaluated with treatment doses ranging from 10-150 mg of TG02. Clinically, treatment with TG02 did not have an effect in AML tumor burden, and most patients at our center only received one cycle of treatment (Roboz et al ASCO 2012 Annual Meeting Abstract #6557, J Clin. Oncol. 30, 2012). However, we found that 8 patient samples showed increased LSPCs in both the bone marrow and peripheral blood. Interestingly, we observed an increase in LSPC cell proliferation, as determined by Ki-67 positive staining. AML colony forming assays also showed increased colony formation (n=5) after one cycle of treatment, which suggests an increase in the frequency of LSPCs. The increase in colony formation in peripheral blood samples suggests mobilization of LSPCs from the marrow into the circulation. Thus, we hypothesized that exposure to TG02 in vivo may result in sensitization to other chemotherapeutic agents, such as Ara-C. We evaluated the effects of Ara-C and other chemotherapeutics, such as vincristine, in primary AML cells obtained from patients before and after treatment with TG02. We found that in vivo exposure to TG02 resulted in significantly increased sensitivity to Ara-C in vitro in 3 out of 4 samples tested Together, our data suggest that TG02 induces an effect in LSCs resulting in increased proliferation and, thus, sensitization to other chemotherapeutic drugs, such as Ara-C. Importantly, although no patients at our center receiving single agent TG02 met the criteria for an objective response, by performing correlative studies in association with the clinical trial, we found the TG02 has a marked effect in AML LSCs that could potentially be exploited by combining it with other agents. Disclosures: Burrows: Tragara Pharmaceuticals: Employment, Equity Ownership. Feldman:Tragara Pharmaceuticals: Consultancy.

scholarly journals Targeting USP47 overcomes tyrosine kinase inhibitor resistance and eradicates leukemia stem/progenitor cells in chronic myelogenous leukemia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hu Lei ◽  
Han-Zhang Xu ◽  
Hui-Zhuang Shan ◽  
Meng Liu ◽  
Ying Lu ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Progenitor Cells ◽  
Chronic Myelogenous Leukemia ◽  
Drug Targets ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Myelogenous Leukemia ◽  
Tki Resistance

AbstractIdentifying novel drug targets to overcome resistance to tyrosine kinase inhibitors (TKIs) and eradicating leukemia stem/progenitor cells are required for the treatment of chronic myelogenous leukemia (CML). Here, we show that ubiquitin-specific peptidase 47 (USP47) is a potential target to overcome TKI resistance. Functional analysis shows that USP47 knockdown represses proliferation of CML cells sensitive or resistant to imatinib in vitro and in vivo. The knockout of Usp47 significantly inhibits BCR-ABL and BCR-ABLT315I-induced CML in mice with the reduction of Lin−Sca1+c-Kit+ CML stem/progenitor cells. Mechanistic studies show that stabilizing Y-box binding protein 1 contributes to USP47-mediated DNA damage repair in CML cells. Inhibiting USP47 by P22077 exerts cytotoxicity to CML cells with or without TKI resistance in vitro and in vivo. Moreover, P22077 eliminates leukemia stem/progenitor cells in CML mice. Together, targeting USP47 is a promising strategy to overcome TKI resistance and eradicate leukemia stem/progenitor cells in CML.

scholarly journals Preferential and persistent impact of acute HIV-1 infection on CD4+ iNKT cells in colonic mucosa

2021 ◽  
Vol 118 (46) ◽  
pp. e2104721118
Author(s):  
Dominic Paquin-Proulx ◽  
Kerri G. Lal ◽  
Yuwadee Phuang-Ngern ◽  
Matthew Creegan ◽  
Andrey Tokarev ◽  
...  
Keyword(s):  
T Cells ◽  
Peripheral Blood ◽  
Colonic Mucosa ◽  
Inkt Cells ◽  
Elevated Expression ◽  
Acute Hiv ◽  
The Impact ◽  
Hiv 1

Acute HIV-1 infection (AHI) results in the widespread depletion of CD4+ T cells in peripheral blood and gut mucosal tissue. However, the impact on the predominantly CD4+ immunoregulatory invariant natural killer T (iNKT) cells during AHI remains unknown. Here, iNKT cells from peripheral blood and colonic mucosa were investigated during treated and untreated AHI. iNKT cells in blood were activated and rapidly depleted in untreated AHI. At the time of peak HIV-1 viral load, these cells showed the elevated expression of cell death–associated transcripts compared to preinfection. Residual peripheral iNKT cells suffered a diminished responsiveness to in vitro stimulation early into chronic infection. Additionally, HIV-1 DNA, as well as spliced and unspliced viral RNA, were detected in iNKT cells isolated from blood, indicating the active infection of these cells in vivo. The loss of iNKT cells occurred from Fiebig stage III in the colonic mucosa, and these cells were not restored to normal levels after initiation of ART during AHI. CD4+ iNKT cells were depleted faster and more profoundly than conventional CD4+ T cells, and the preferential infection of CD4+ iNKT cells over conventional CD4+ T cells was confirmed by in vitro infection experiments. In vitro data also provided evidence of latent infection in iNKT cells. Strikingly, preinfection levels of peripheral blood CD4+ iNKT cells correlated directly with the peak HIV-1 load. These findings support a model in which iNKT cells are early targets for HIV-1 infection, driving their rapid loss from circulation and colonic mucosa.

scholarly journals The influence in vivo of murine colony-stimulating factor-1 on myeloid progenitor cells in mice recovering from sublethal dosages of cyclophosphamide

Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 913-918 ◽  
Author(s):  
HE Broxmeyer ◽  
DE Williams ◽  
S Cooper ◽  
A Waheed ◽  
RK Shadduck
Keyword(s):  
Progenitor Cells ◽  
Colony Formation ◽  
Colony Stimulating Factor ◽  
Myeloid Progenitor ◽  
Accessory Cells ◽  
Myeloid Progenitor Cells ◽  
In Vivo Administration ◽  
Stimulating Factor

Abstract Pure murine colony-stimulating factor-1 (CSF-1) was assessed for its effects in vivo in mice pretreated seven days earlier with a sublethal dosage of cyclophosphamide. The multipotential (CFU-GEMM), erythroid (BFU-E), and granulocyte-macrophage (CFU-GM) progenitor cells in these mice were in a slowly cycling or noncycling state. Intravenous administration of 20,000 units of CSF-1 to these mice stimulated the hematopoietic progenitors into a rapidly cycling state in the marrow and spleen within three hours. Significant increases in absolute numbers of marrow and spleen CFU-GM and spleen BFU-E and CFU-GEMM were also detected. No endotoxin was detected in the CSF-1 preparation by Limulus lysate assay, and treatment of CSF-1 at 100 degrees C for 20 to 30 minutes completely inactivated the in vitro and in vivo stimulating effects. The effects of CSF-1 were not mimicked by the in vivo administration of 0.1 to 10 ng Escherichia coli lipopolysaccharide. These results suggest that the effects of CSF-1 in vivo were not due to contaminating endotoxin or to a nonspecific protein effect. CSF-1 did not enhance colony formation by BFU-E or stimulate colony formation by CFU-GEMM in vitro, thus suggesting that at least some of the effects of CSF-1 noted in vivo are probably indirect and mediated by accessory cells.

Selective elimination of leukemic CD34+ progenitor cells by cytotoxic T lymphocytes specific for WT1

Blood ◽  
2000 ◽  
Vol 95 (7) ◽  
pp. 2198-2203 ◽  
Author(s):  
Liquan Gao ◽  
Ilaria Bellantuono ◽  
Annika Elsässer ◽  
Stephen B. Marley ◽  
Myrtle Y. Gordon ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Chronic Myeloid Leukemia ◽  
T Lymphocytes ◽  
Progenitor Cells ◽  
Cytotoxic T Lymphocytes ◽  
Colony Formation ◽  
Myeloid Leukemia ◽  
Leukemia Cell

Abstract Hematologic malignancies such as acute and chronic myeloid leukemia are characterized by the malignant transformation of immature CD34+ progenitor cells. Transformation is associated with elevated expression of the Wilm's tumor gene encoded transcription factor (WT1). Here we demonstrate that WT1 can serve as a target for cytotoxic T lymphocytes (CTL) with exquisite specificity for leukemic progenitor cells. HLA-A0201– restricted CTL specific for WT1 kill leukemia cell lines and inhibit colony formation by transformed CD34+ progenitor cells isolated from patients with chronic myeloid leukemia (CML), whereas colony formation by normal CD34+ progenitor cells is unaffected. Thus, the tissue-specific transcription factor WT1 is an ideal target for CTL-mediated purging of leukemic progenitor cells in vitro and for antigen-specific therapy of leukemia and other WT1-expressing malignancies in vivo.

Comparison between Progenitor Cells from Mobilized Peripheral Blood (PB) in Healthy Donors and Non-Hodgkin’s Lymphoma (NHL) Patients.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 5002-5002
Author(s):  
Eva M. Villaron ◽  
Julia Almeida ◽  
Natalia Lopez-Holgado ◽  
Fermin M. Sanchez-Guijo ◽  
Mercedes Alberca ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Peripheral Blood ◽  
Progenitor Cell ◽  
Functional Assays ◽  
Healthy Donors ◽  
Cd34 Cells ◽  
Cell Subpopulations ◽  
The Impact ◽  
Pbsc Mobilization

Abstract INTRODUCTION: Peripheral blood stem cell (PBSC) mobilization is impaired in patients receiving chemotherapy but, as far as we know there is no data about the impact of chemotherapy on different PB progenitor cell subpopulations. AIM: to ascertain whether or not immature or committed progenitor cell are affected by chemotherapy prior PBSC mobilization in NHL patients. MATERIAL AND METHODS: a total of 27 PB samples from NHL patients and 36 PB samples from healthy donors were studied. Immunophenotypic analysis of CD34+ cell subpopulations was performed using the following four colour combinations of monoclonal antibodies (FITC/PE/PC5/APC): CD90/CD133/CD38/CD34 and CD71/CD13/CD45/CD34. In order to study committed progenitor cells “in vitro”, standard colony-forming assays were used and, in order to investigate the behaviour of the uncommitted progenitors Delta Assays of plastic adherent progenitor cells (PΔ) were performed. RESULTS: The comparison between NHL patients and healthy donors is shown in Table 1. The relationship between data obtained by flow cytometry and cultures was statistically significant (p<0.05, r>0.568) for all the progenitors analysed. Table 1: Results of Immunophenotypic and Functional Assays LNH patients Healthy donors p Data expressed as median (range). 1. Percentage among CD34+ cells. 2. Number of CFU/10 5 planted cells. 3. Number of CFU/10 6 planted cells % CD34 0.16(0.04–3.65) 0.57(0.11–1.81) 0.013 Immunophenotypic Data Erithroid 1 0.05(0.01–0.60) 0.14(0.02–0.42) 0.098 Myelo–monocytic 1 0.11(0.02–2.41) 0.37(0.07–1.18) 0.014 Immature 1 0.01(0.00–0.63) 0.05(0.01–0.19) 0.014 CFU-GM 2 70(4–440) 90(0–904) 0.327 Clonogenic and Delta Assays data BFU-E 2 62(6–172) 85(0–240) 0.046 CFU-Mix 2 18(0–124) 42(0–140) 0.018 CFU Δ3 356(0–3509) 953(90–8320) 0.033 CONCLUSIONS: We can conclude that in NHL, mobilized committed and above all immature progenitors are impaired when compared with healthy subjects, both analysed by immunological and functional assays. Only granulomonocytic progenitors analysed by a functional approach seemed to be preserved.

Disruption of GAS6-MER Pathway Leads to Defects in Physiological Clearance of Expelled Nuclei from Erythroblasts by Bone Marrow Macrophages

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 499-499
Author(s):  
Linda Kadi ◽  
Laurent Burnier ◽  
Rocco Sugamele ◽  
Peter Carmeliet ◽  
Greg Lemke ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Fetal Liver ◽  
Specific Gene ◽  
Positive Staining ◽  
Morphological Examination ◽  
Double Positive ◽  
Blood Island

Abstract Late in erythropoiesis, nuclei are expelled from erythroblasts and 2×1011 anucleated new red blood cells are daily delivered in the peripheral blood. Expelled nuclei expose phosphatidylserine (PS) on their surface, which is used as an “eat me” signal for their engulfment by macrophages located in the blood island. The two PS opsonins, milk-fatglobule EGF8 (MFG-E8) and Growth arrest-specific gene 6 product (GAS6) together with their respective receptors αvβ5/αvβ3 and TAM (TYRO3, AXL and MER), are involved in the phagocytosis of apoptotic cells, but their role in the phagocytosis of expelled nuclei from erythroblasts is not determined. Because fetal liver and bone marrow macrophages do not express MFG-E8, the GAS6-MER pathway might constitute a crucial pathway for the engulfment of nuclei expelled from erythroblasts. To test this hypothesis, we isolated nuclei from late-stage erythroblasts from spleens of phlebotomized mice, and studied nuclei internalization capacity of bone marrow derived macrophages (BMDM) from mice deficient either in GAS6 (GAS6−/−), AXL (AXL−/−) or TYRO3 (TYRO3−/−), or lacking MER kinase domain (MERkd). Released nuclei were identified by flow cytometry according to their size and their double positive staining for the erythroid lineage marker Ter119 and Annexin V for PS. Purity of the preparation was checked by morphological examination of cytospin preparations. In vitro phagocytosis assays show that GAS6−/− BMDM cleared 30% less nuclei than wild-type (WT) BMDM. We observed a slight decrease of internalization capacity for AXL−/− BMDM, whereas TYRO3−/− BMDM engulfed the nuclei as efficiently as WT BMDM. In contrast, MER deficiency nearly abolished nuclei phagocytosis. AXL−/−/TYRO3−/− and AXL−/−/MERkd BMDM were tested and did not show any cumulative effects when compared to WT and single knockouts. We also investigated the signalling pathway downstream of MER in BMDM. In particular, we assessed the expression of the activated form of Rac1, which is crucial for the cytoskeletal reorganization in phagocytosis. Activation of Rac1 after the initiation of the phagocytosis was delayed for 45 minutes in MERkd as compared to WT BMDM. In vivo, we found an accumulation of nuclei in MERkd mice 4 days post phlebotomy, when erythropoiesis is increased in response to anemia. Nuclei circulated in the blood of MERkd mice at a level of 0.08 ± 0.042 G/L and were identified on peripheral blood smears of these mice whereas they were undetectable in the blood of WT mice. We demonstrated an increase of a double labelled Ter119/AnnexinV population corresponding to nuclei in BM (2-fold) and spleen (1.5-fold) of MERkd mice as compared to WT mice. The augmentation of this double labelled population in the MERkd mice translated the phenotype of splenomegaly of these mice. Hematocrit and reticulocyte levels were comparable between WT and MERkd as previously reported (JCI118:583–596, 2008). Thus, MER was critical for in vitro phagocytosis of nuclei from erythroblasts whereas the role of AXL and TYRO3 appeared to be negligible. GAS6 binding to nuclei exposing PS on their surface might form a bridge between PS and MER receptor on BMDM, allowing nuclei clearance. In vivo, the absence of MER caused an accumulation of nuclei in BM and spleen and their appearance in circulating blood due to their inefficient elimination during erythropoietic response to anemia. In conclusion, we postulate that GAS6 and its receptor MER were involved in late erythropoiesis when nuclei are expelled from the erythroblasts and engulfed by BMDM in the blood island, through Rac1 activation.

The Vent-Like Homeobox Gene VENTX Promotes Human Myeloid Development and Is Highly Expressed In Acute Myeloid Leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 739-739
Author(s):  
Vijay P. S. Rawat ◽  
Natalia Arseni ◽  
Farid Ahmed ◽  
Medhanie A. Mulaw ◽  
Silvia Thoene ◽  
...  
Keyword(s):  
Gene Expression ◽  
Progenitor Cells ◽  
Cell Lines ◽  
Myeloid Cells ◽  
Lymphoid Cells ◽  
Hematopoietic Development ◽  
Cd34 Cells ◽  
The Impact

Abstract Abstract 739 Recent studies suggest that a variety of regulatory molecules active in embryonic development such as clustered and non-clustered homeobox genes play an important role in normal and malignant hematopoiesis. Since it was shown that the Xvent-2 homeobox gene is part of the BMP-4 signalling pathway in Xenopus, it is of particular interest to examine the expression profile and function of its only recently discovered human homologue VENTX in hematopoietic development. Expression of the VENTX gene was analyzed in normal human hematopoiesis and AML patients samples by microarray and qPCR. To test the impact of the constitutive expression of VENTX on human progenitor cells, CD34+ cord blood (CB) cells were retrovirally transduced with VENTX or the empty control vector and analyzed using in vitro and in vivo assays. So far we and others have not been able to identify a murine Xenopus xvent gene homologue. However, we were able to document the expression of this gene by qPCR in human lineage positive hematopoietic subpopulations. Amongst committed progenitors VENTX was significantly 13-fold higher expressed in CD33+ BM myeloid cells (4/4 positive) compared to CD19+ BM lymphoid cells (5/7 positive, p=0.01). Of note, expression of VENTX was negligible in normal CD34+/CD38− but detectable in CD34+ BM human progenitor cells. In contrast to this, leukemic CD34+/CD38− from AML patients (n=3) with translocation t(8,21) showed significantly elevated expression levels compared to normal CD34+ BM cells (n=5) (50-fold higher; p≤0.0001). Furthermore, patients with normal karyotype NPM1c+/FLT3-LM− (n=9), NPM1c−/FLT3-LM+ (n=8) or patients with t(8;21) (n=9) had an >100-fold higher expression of VENTX compared to normal CD34+ BM cells and a 5- to 7.8-fold higher expression compared to BM MNCs. Importantly, lentivirus-mediated long-term silencing of VENTX in human AML cell lines (mRNA knockdown between 58% and 75%) led to a significant, reduction in cell number compared to the non-silencing control construct (>79% after 120h). Suggesting that growth of human leukemic cell lines depends on VENTX expression in vitro. As we observed that VENTX is aberrantly expressed in leukemic CD34+ cells with negligible expression in normal counterparts, we assessed the impact of forced VENTX gene expression in normal CD34+ human progenitor cells on the transcription program. Gene expression and pathway analysis demonstrated that in normal CD34+ cells enforced expression of VENTX initiates genes associated with myeloid development (CD11b, CD125, CD9,CD14 and M-CSF), and downregulates genes involved in early lymphoid development (IL-7, IL-9R, LEF1/TCF and C-JUN) and erythroid development such as EPOR, CD35 and CD36. We then tested whether enforced expression of VENTX in CD34+ cells is able to alter the hematopoietic development of early human progenitors as indicated by gene expression and pathway analyses. Functional analyses confirmed that aberrant expression of VENTX in normal CD34+ human progenitor cells induced a significant increase in the number of myeloid colonies compared to the GFP control with 48 ± 6.5 compared to 28.9 ± 4.8 CFU-G per 1000 initially plated CD34+ cells (n=11; p=0.03) and complete block in erythroid colony formation with an 81% reduction of the number of BFU-E compared to the control (n=11; p<0.003). In a feeder dependent co-culture system, VENTX impaired the development of B-lymphoid cells. In the NOD/SCID xenograft model, VENTX expression in CD34+ CB cells promoted generation of myeloid cells with an over 5-fold and 2.5-fold increase in the proportion of human CD15+ and CD33+ primitive myeloid cells compared to the GFP control (n=5, p=0.01). Summary: Overexpression of VENTX perturbs normal hematopoietic development, promotes generation of myeloid cells and impairs generation of lymphoid cells in vitro and in vivo. Whereas VENTX depletion in human AML cell lines impaired their growth.Taken together, these data extend our insights into the function of human embryonic mesodermal factors in human hematopoiesis and indicate a role of VENTX in normal and malignant myelopoiesis. Disclosures: No relevant conflicts of interest to declare.

Novel In Vivo Evidence That Not Only Androgens But Also Pituitary Gonadotropins and Prolactin Directly Stimulate Murine Bone Marrow Stem Cells – Implications For Potential Treatment Strategies In Aplastic Anemias

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2476-2476
Author(s):  
Kasia Mierzejewska ◽  
Ewa Suszynska ◽  
Sylwia Borkowska ◽  
Malwina Suszynska ◽  
Maja Maj ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Progenitor Cells ◽  
Sex Hormones ◽  
Peripheral Blood ◽  
Hematopoietic Stem ◽  
Clonogenic Potential

Abstract Background Hematopoietic stem/progenitor cells (HSPCs) are exposed in vivo to several growth factors, cytokines, chemokines, and bioactive lipids in bone marrow (BM) in addition to various sex hormones circulating in peripheral blood (PB). It is known that androgen hormones (e.g., danazol) is employed in the clinic to treat aplastic anemia patients. However, the exact mechanism of action of sex hormones secreted by the pituitary gland or gonads is not well understood. Therefore, we performed a complex series of experiments to address the influence of pregnant mare serum gonadotropin (PMSG), luteinizing hormone (LH), follicle-stimulating hormone (FSH), androgen (danazol) and prolactin (PRL) on murine hematopoiesis. In particular, from a mechanistic view we were interested in whether this effect depends on stimulation of BM-residing stem cells or is mediated through the BM microenvironment. Materials and Methods To address this issue, normal 2-month-old C57Bl6 mice were exposed or not to daily injections of PMSG (10 IU/mice/10 days), LH (5 IU/mice/10 days), FSH (5 IU/mice/10 days), danazol (4 mg/kg/10 days) and PRL (1 mg/day/5days). Subsequently, we evaluated changes in the BM number of Sca-1+Lin–CD45– that are precursors of long term repopulating hematopoietic stem cells (LT-HSCs) (Leukemia 2011;25:1278–1285) and bone forming mesenchymal stem cells (Stem Cell & Dev. 2013;22:622-30) and Sca-1+Lin–CD45+ hematopoietic stem/progenitor cells (HSPC) cells by FACS, the number of clonogenic progenitors from all hematopoietic lineages, and changes in peripheral blood (PB) counts. In some of the experiments, mice were exposed to bromodeoxyuridine (BrdU) to evaluate whether sex hormones affect stem cell cycling. By employing RT-PCR, we also evaluated the expression of cell-surface and intracellular receptors for hormones in purified populations of murine BM stem cells. In parallel, we studied whether stimulation by sex hormones activates major signaling pathways (MAPKp42/44 and AKT) in HSPCs and evaluated the effect of sex hormones on the clonogenic potential of murine CFU-Mix, BFU-E, CFU-GM, and CFU-Meg in vitro. We also sublethally irradiated mice and studied whether administration of sex hormones accelerates recovery of peripheral blood parameters. Finally, we determined the influence of sex hormones on the motility of stem cells in direct chemotaxis assays as well as in direct in vivo stem cell mobilization studies. Results We found that 10-day administration of each of the sex hormones evaluated in this study directly stimulated expansion of HSPCs in BM, as measured by an increase in the number of these cells in BM (∼2–3x), and enhanced BrdU incorporation (the percentage of quiescent BrdU+Sca-1+Lin–CD45– cells increased from ∼2% to ∼15–35% and the percentage of BrdU+Sca-1+Lin–CD45+ cells increased from 24% to 43–58%, Figure 1). These increases paralleled an increase in the number of clonogenic progenitors in BM (∼2–3x). We also observed that murine Sca-1+Lin–CD45– and Sca-1+Lin–CD45+ cells express sex hormone receptors and respond by phosphorylation of MAPKp42/44 and AKT in response to exposure to PSMG, LH, FSH, danazol and PRL. We also observed that administration of sex hormones accelerated the recovery of PB cell counts in sublethally irradiated mice and slightly mobilized HSPCs into PB. Finally, in direct in vitro clonogenic experiments on purified murine SKL cells, we observed a stimulatory effect of sex hormones on clonogenic potential in the order: CFU-Mix > BFU-E > CFU-Meg > CFU-GM. Conclusions Our data indicate for the first time that not only danazol but also several pituitary-secreted sex hormones directly stimulate the expansion of stem cells in BM. This effect seems to be direct, as precursors of LT-HSCs and HSPCs express all the receptors for these hormones and respond to stimulation by phosphorylation of intracellular pathways involved in cell proliferation. These hormones also directly stimulated in vitro proliferation of purified HSPCs. In conclusion, our studies support the possibility that not only danazol but also several other upstream pituitary sex hormones could be employed to treat aplastic disorders and irradiation syndromes. Further dose- and time-optimizing mouse studies and studies with human cells are in progress in our laboratories. Disclosures: No relevant conflicts of interest to declare.

Temozolomide, irradiation and hypoxia promote homing of hematopoietic progenitor cells towards gliomas

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 20044-20044
Author(s):  
W. Wick ◽  
G. Tabatabai ◽  
B. Frank ◽  
M. Weller
Keyword(s):  
Progenitor Cells ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Tumor Hypoxia ◽  
Glioma Cells ◽  
Signaling Cascade ◽  
Hematopoietic Stem ◽  
The Impact

20044 Background: Temozolomide and irradiation are essential parts of the standard therapy and hypoxia is a critical aspect of the microenvironment of gliomas. IN the present study, we aimed at investigating the impact of these stimuli on the previously defined transforming growth factor beta (TGF-β)- and stromal cell-derived factor-1/CXC chemokine ligand 12 (SDF-1α/CXCL12)-dependent migration of adult hematopoietic stem and progenitor cells (HPC) towards glioma cells in vitro and the homing to experimental gliomas in vivo. Hyperthermia served as control. Methods and Results: Cerebral irradiation of nude mice at 21 days after intracerebral implantation of LNT-229 glioma induces tumor satellite formation and enhances the glioma tropism of HPC in vivo. Supernatants of temozolomide-treated, irradiated or hypoxic LNT-229 glioma cells promote HPC migration in vitro. Reporter assays reveal that the CXCL12 promoter activity is enhanced in LNT-229 glioma cells at 24 h after irradiation at 8 Gy or after exposure to 1% oxygen for 12 h. The irradiation- and hypoxia-induced release of CXCL12 depends on hypoxia inducible factor-1 alpha (HIF-1α), but not on p53. Induction of transcriptional activity of HIF-1α by hypoxia and irradiation requires an intact signaling cascade of TGF-β. Conclusions: Thus, we delineate a novel stress signaling cascade in glioma cells involving TGF-β, HIF-1α and CXCL12. Stress stimuli can be temozolomide, irradiation and hypoxia but not hyperthermia. These data suggest that the use of HPC as cellular vectors in the treatment of glioblastoma may well be combined with anti-angiogenic therapies which induce tumor hypoxia. [Table: see text]

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