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Ruth Pettengell

Publications and source records attributed to Ruth Pettengell.

18 recordsLinked to original sources
PubMed2006

Endolyn (CD164) modulates the CXCL12-mediated migration of umbilical cord blood CD133+ cells.

Hematopoietic stem cell/hematopoietic progenitor cell (HSC/HPC) homing to specific microenvironmental niches involves interactions between multiple receptor ligand pairs. Although CXCL12/CXCR4 plays a central role in these events, CXCR4 regulators that provide the specificity for such cells to lodge and be retained in particular niches are poorly defined. Here, we provide evidence that the sialomucin endolyn (CD164), an adhesion receptor that regulates the adhesion of CD34+ cells to bone marrow stroma and the recruitment of CD34+CD38(lo/-) cells into cycle, associates with CXCR4. The class II 103B2 monoclonal antibody, which binds the CD164 N-linked glycan-dependent epitope or CD164 knockdown by RNA interference, significantly inhibits the migration of CD133+ HPCs toward CXCL12 in vitro. On presentation of CXCL12 on fibronectin, CD164 associates with CXCR4, an interaction that temporally follows the association of CXCR4 with the integrins VLA-4 and VLA-5. This coincides with PKC-zeta and Akt signaling through the CXCR4 receptor, which was disrupted on the loss of CD164 though MAPK signaling was unaffected. We therefore demonstrate a novel association among 3 distinct families of cell-surface receptors that regulate cell migratory responses and identify a new role for CD164. We propose that this lends specificity to the homing and lodgment of these cells within the bone marrow niche.

AC133 Antigen↗
PubMed2006

Neutropenic event risk and impaired chemotherapy delivery in six European audits of breast cancer treatment.

GOALS OF WORK: The aims of this study were to assess chemotherapy treatment characteristics, neutropenic event (NE) occurrence and related risk factors in breast cancer patients in Western Europe. MATERIALS AND METHODS: Six retrospective audits of breast cancer chemotherapy were combined into a dataset of 2,860 individuals. NEs were defined as neutropenia-related hospitalisation, dose reduction > or = 15% or dose delay > or = 7 days. Summation dose intensity (SDI) was calculated to compare different types of chemotherapy regimens on a single scale. Risk factors of NE occurrence and of low relative dose intensity (RDI) < or = 85% were identified by multiple logistic regression. MAIN RESULTS: Patient populations were comparable between audits. Until 1998, cyclophosphamide, methotrexate and fluorouracil regimens were most frequently used, but thereafter, anthracycline-based regimens were most common. NEs occurred in 20% of the patients and low RDI in 16%. NE occurrence predicted low RDI and was associated with higher age, bigger body surface area, lower body mass index, regimen type, more chemotherapy cycles planned, normal to high SDI, concomitant radiotherapy and year of treatment. First cycle NE occurrence predicted NEs from cycle 2 onwards. A risk score using age, SDI, number of planned chemotherapy cycles and concomitant radiotherapy differentiated patients with increasing NE risk (9-37%). An alternative score version not using concomitant radiotherapy performed moderately less well. CONCLUSIONS: NEs occurred frequently in this combined dataset and they affected treatment delivery. Identifying patients at high NE risk enables targeted prophylaxis and may avoid dose limitations.

Adult↗
PubMed2006

CHOP-like chemotherapy plus rituximab versus CHOP-like chemotherapy alone in young patients with good-prognosis diffuse large-B-cell lymphoma: a randomised controlled trial by the MabThera International Trial (MInT) Group.

BACKGROUND: The role of rituximab in combination with different CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)-like chemotherapy regimens in young patients with good-prognosis diffuse large-B-cell lymphoma remains to be defined. We aimed to compare CHOP-like chemotherapy and rituximab with CHOP-like chemotherapy alone in these patients. METHODS: 824 patients who were from 18 countries; aged 18-60 years; and who had no risk factors or one risk factor according to age-adjusted International Prognostic Index (IPI), stage II-IV disease, or stage I disease with bulk were enrolled. These patients were randomly assigned to six cycles of CHOP-like chemotherapy and rituximab (n=413) or to six cycles of CHOP-like chemotherapy alone (n=411). Bulky and extranodal sites received additional radiotherapy. The primary endpoint was event-free survival; secondary endpoints were response, progression under therapy, progression-free survival, overall survival, and frequency of toxic effects. Analyses were done by intention to treat and per protocol. This trial is registered at http://www.clinicaltrials.gov, NCT 00064116. FINDINGS: After a median follow-up of 34 months (range 0.03-61), patients assigned chemotherapy and rituximab had increased 3-year event-free survival compared with those assigned chemotherapy alone (79% [95% CI 75-83] vs 59% [54-64]; difference between groups 20% [13-27], log-rank p<0.0001), and had increased 3-year overall survival (93% [90-95] vs 84% [80-88]; difference between groups 9% [3-13], log-rank p=0.0001). Event-free survival was affected by treatment group, presence of bulky disease, and age-adjusted IPI: after chemotherapy and rituximab, a favourable subgroup (ie, IPI=0, no bulk) could be defined from a less-favourable subgroup (ie, IPI=1 or bulk, or both). Groups did not differ in the frequency of adverse events. INTERPRETATION: Rituximab added to six cycles of CHOP is an effective treatment for young patients with good-prognosis diffuse large-B-cell lymphoma. The definition of two prognostic subgroups allows for a more refined therapeutic approach for these patients.

Adolescent↗
PubMed2005

HOXA9 expression increases with age in human haemopoietic cells.

HOXA9 is a transcription factor with a central role in both haemopoiesis and leukaemia, and has been extensively studied over the past decade. Most notably, high levels of HOXA9 expression in haemopoietic cells is a characteristic feature of acute myeloid leukaemia (AML), and indeed may be sufficient in its own right to cause this disease. Here, we show that HOXA9 expression changes dramatically with age, whereby a uniformly low level of expression during early adulthood is replaced by a frequently very high expression in adults over sixty.

Adolescent↗
PubMed2004

The double life of HOXB4.

HOXB4 is a homeodomain-containing transcription factor with diverse roles in embryonic development and the regulation of adult stem cells. Intriguingly, this gene can act in opposite ways when expressed by different cells, promoting the proliferation of stem cells whilst activating the apoptotic pathway in some embryonic structures. This review considers the basis for these differences in terms of the molecular biology of HOXB4 and the cells that express it.

Animals↗
PubMed2004

Umbilical cord blood stem cells can expand hematopoietic and neuroglial progenitors in vitro.

The ability of hematopoietic tissue-derived adult stem cells to transdifferentiate into neural progenitor cells offers an interesting alternative to central nervous system (CNS)- or embryonic-derived stem cells as a viable source for cellular therapies applied to brain regeneration. Umbilical cord blood (CB) due to its primitive nature and it unproblematic collection appears as a promising candidate for multipotent stem cell harvest. We developed a negative immunomagnetic selection method that depletes CB from hematopoietic lineage marker-expressing cells, hence isolating a discrete lineage negative (LinNeg) stem cell population (0.1% of CB mononucleated cell [MCN] population). In liquid culture supplemented with thrombopoietin, flt-3 ligand, and c-kit ligand (TPOFLK), CB LinNeg stem cells could expand primitive nonadherent hematopoietic progenitors (up to 47-fold) and simultaneously produce slow-dividing adherent cells with neuroglial progenitor cell morphology over 8 weeks. Laser scanning confocal microscopy analysis identified these adherent cells to express glial fibrillary acidic protein (GFAP). Gene expression analysis showed upregulation of primitive neuroglial progenitor cell markers including, GFAP, nestin, musashi-1, and necdin. ELISA quantification of liquid culture supernatant revealed the in vitro release of transforming growth factor beta-1 (TGFbeta1), glial cell line-derived neurotrophic factor (GDNF) suggesting their contribution to CB LinNeg stem cell transdifferentiation into neuroglial progenitors. Our study supports that a single CB specimen can be pre-expanded in TPOFLK to produce both primitive hematopoietic and neuropoietic progenitors, hence widening CB clinical potential for cellular therapies.

Biomarkers↗
PubMed2004

Pbx genes are required in Xenopus lens development.

Development of the vertebrate eye is dependent on multiple tissue interactions and distinct sets of transcription factors and signalling molecules. The latter are thought to be FGF8 and BMP4, proteins secreted from the neural plate to induce lens formation in the overlying ectoderm. Here we show that the Pbx transcription factor plays a crucial role in this process, as it is required for FGF8 expression in the neural plate and is thus part of the complex hierarchy of genes involved in lens induction.

Animals↗
PubMed2004

Characterization of a lineage-negative stem-progenitor cell population optimized for ex vivo expansion and enriched for LTC-IC.

Current hematopoietic stem cell transplantation protocols rely heavily upon CD34+ cells to estimate hematopoietic stem and progenitor cell (HSPC) yield. We and others previously reported CD133+ cells to represent a more primitive cell population than their CD34+ counterparts. However, both CD34+ and CD133+ cells still encompass cells at various stages of maturation, possibly impairing long-term marrow engraftment. Recent studies demonstrated that cells lacking CD34 and hematopoietic lineage markers have the potential of reconstituting long-term in vivo hematopoiesis. We report here an optimized, rapid negative-isolation method that depletes umbilical cord blood (UCB) mononucleated cells (MNC) from cells expressing hematopoietic markers (CD45, glycophorin-A, CD38, CD7, CD33, CD56, CD16, CD3, and CD2) and isolates a discrete lineage-negative (Lin-) cell population (0.10% +/- 0.02% MNC, n=12). This primitive Lin- cell population encompassed CD34+/- and CD133+/- HSPC and was also enriched for surface markers involved in HSPC migration, adhesion, and homing to the bone marrow (CD164, CD162, and CXCR4). Moreover, our depletion method resulted in Lin- cells being highly enriched for long-term culture-initiating cells when compared with both CD133+ cells and MNC. Furthermore, over 8 weeks in liquid culture stimulated by a cytokine cocktail optimized for HSPC expansion, TPOFLK (thrombopoietin 10 ng/ml, Flt3 ligand 50 ng/ml, c-Kit ligand 20 ng/ml) Lin- cells underwent slow proliferation but maintained/expanded more primitive HSPC than CD133+ cells. Therefore, our Lin- stem cell offers a promising alternative to current HSPC selection methods. Additionally, this work provides an optimized and well-characterized cell population for expansion of UCB for a wider therapeutic potential, including adult stem cell transplantation.

Antigens, Surface↗
PubMed2003

Multiparametric analysis of immature cell populations in umbilical cord blood and bone marrow.

Adult stem cells are finding increased therapeutic potential not least in tissue regeneration protocols. The cell sources being proposed for such protocols include embryonic, umbilical cord blood (CB) and adult bone marrow (BM). Although embryonic sources are controversial, CB and marrow are available immediately. The appropriate cells of use in these sources are considered to be extremely rare and a characterisation of the starting cell source is important for the development of adult stem cell protocols and ex vivo expansion. Umbilical CB and BM mononuclear cells were labelled for the antigens CD34, CD133, CD117, CD164, Thy-1 or CD38, and additional intracellular CD34 antigen. Three dimensional flow-cytometric analyses were carried out together with dual laser confocal microscope analysis for antigen profile expression. Variable levels of immaturity were detected on CB and BM populations using internal and external CD34 antigen. For CB and BM cells, internal CD34 (intCD34+) could be detected on co-expressing CD133+ cells before expression of external CD34 antigen (extCD34+). CD38 co-expression analysis also showed that a small but distinct group of cells expressing low CD38 and no external CD34 antigen could be detected. Additional phenotyping of these cells using CD117, Thy-1, CD164 and CD133 demonstrated variable primitive status detectable within the external CD34- population. Newly harvested primary CB and BM populations were shown to contain not only cellular populations of known standard sequential maturity but also populations of more extreme rarity. The presence of cells which lacked extracellular CD34 antigen, in both CB and BM, but which possessed CD133, has important implications for purification of human stem cells in clinical applications.

Antigens, CD↗
PubMed2003

Position paper on the therapeutic use of rituximab in CD20-positive diffuse large B-cell non-Hodgkin's lymphoma.

The available data on rituximab in combination with chemotherapy confirm that the addition of an independently active biological agent to full-dose standard chemotherapy results in higher rates of complete response, lower rates of relapse, prolonged survival, little additional toxicity and no compromise of the dose intensity of standard chemotherapy regardless of age and risk group. Given the strength of these data, the British Committee for Standards in Haematology believes that rituximab should be available for prescription by UK haematologists and oncologists according to its licensed indication in patients with diffuse large B-cell lymphoma until further data are available to confirm or refute these results. We consider that the use of rituximab with chemotherapy in aggressive lymphoma is cost-effective and that failure to support its introduction will be strongly in conflict with professional and patient opinion.

Antibodies, Monoclonal↗
PubMed2003

Three-dimensional analysis of CD34 sialomucin distribution on cord blood and bone marrow.

Determining the cellular distribution of key adhesion molecules may aid in understanding haematopoietic progenitor/stem cell (HPSC) homing to bone marrow (BM). CD34, a well-characterized marker for blast-like HPSC, is widely used for the isolation and enumeration of HPSC. Functional studies have yet to identify a ligand for CD34. However, growing evidence suggests that CD34 may aid the regulation of HPSC differentiation and modulate the expression of other HPSC adhesion molecules necessary for homing. This study aimed to determine CD34 distribution on umbilical cord blood (CB) and BM. CD34-selected cells were adhered to positively charged gold slides at room temperature, before indirect fluorescent antibody labelling with fluorescein isothiocyanate. Fluorescent distribution was determined by 1-microm interval, confocal laser scanning microscope Z-sections. Initial analysis showed CD34 distributed within peripheral halos and dense pocket regions. The development of three-dimensional imaging software enabled spatial visualization of CD34 distribution on CB and BM in association with differential interference contrast cell image. This showed that CD34 was distributed within peripheral halos, with magnupodia-associated 'meridian-shaped crescents', extending from points of cell-slide adhesion towards the top of the cell. True CD34 distribution, not previously discernible by confocal laser scanning microscopy alone, suggests a possible role in cell adhesion/homing revealed by three-dimensional imaging.

Antigens, CD34↗
PubMed2003

Colocalization analysis of sialomucins CD34 and CD164.

Flow cytometric protocols are employed to identify and characterize hemopoietic stem/progenitor populations before transplantation. Cell surface antigens, including CD34, are employed in this process and widely used in harvest protocols, which largely ignores the potential functional role of such antigens. Transmembrane glycoprotein sialomucins, including CD34 and CD164, have been implicated in cell-to-cell interactions and activation. CD164, also expressed on early hemopoietic populations, was reported to have a possible function facilitating CD34(+) cells to adhere to bone marrow stroma. In this study, we employed high-definition laser-scanning confocal microscopy to investigate CD34 and CD164 surface co-localization patterns on bone marrow and cord blood cells and to compare the expression patterns using a three-dimensional computer-generated method developed in house. Differential interference microscopy analysis revealed bone marrow membrane activity was higher than the corresponding cord blood counterpart, perhaps indicating the marrow microenvironmental nature. Fluorescence analysis of CD34 and CD164 antigens showed both were expressed first in a halo-like pattern and second in antigen-dense pockets. Three-dimensional computer analyses further revealed that this pocketing corresponded to dense crest-like surface structures appearing to rise from the point of adherence on the slide. Further, it was found that CD34 and CD164 display strong colocalization patterns on cells expressing both antigens. The dual nature of the CD34 and CD164 antigens discovered here lends further evidence to the previous literature implicating a strong functional link between these two sialomucins, which should be considered in the transplantation arena and in the function of such sialomucins as negative regulators of cell proliferation.

Antigens, CD34↗
PubMed2002

Role of nonmyeloablative allogeneic stem-cell transplantation after failure of autologous transplantation in patients with lymphoproliferative malignancies.

PURPOSE: Conventional allogeneic stem-cell transplantation (SCT) after a prior failed autograft is associated with a transplant-related mortality rate of 50% to 80%. The aim of the current study was to evaluate the safety and efficacy of sibling, HLA-matched, nonmyeloablative allogeneic SCT with donor lymphocyte infusion (DLI) in patients with lymphoid malignancy after failure of autologous SCT. PATIENTS AND METHODS: A total of 38 patients with refractory, progressive, or relapsed disease after autologous SCT were entered onto this study. The conditioning regimen consisted of the humanized monoclonal antibody CAMPATH-1H, fludarabine, and melphalan. Fifteen of 35 assessable patients received DLI after SCT. RESULTS: Sustained neutrophil engraftment was achieved in 37 recipients, and platelet engraftment was achieved in 35 patients. The estimated transplant-related mortality was 7.9% at day 100 and 20% at 14 months, the median duration of follow-up. Eight patients experienced grade I/II acute graft-versus-host disease (GVHD) after transplantation, but no grade III/IV GVHD was observed in this setting. However, grade III/IV GVHD occurred in seven patients who received DLI. The actuarial overall survival at 14 months was 53%, with a progression-free survival of 50%. DLI produced a further response in three of 15 recipients. CONCLUSION: Nonmyeloablative allogeneic SCT after CAMPATH-1H-containing conditioning is a relatively safe option compared with conventional allogeneic transplantation for patients who have failed previous autologous SCT. The low incidence of early GVHD enabled the subsequent administration of DLI to improve further clinical responses in this poor-risk group of lymphoma and myeloma patients.

Adult↗
PubMed2002

AC133+ umbilical cord blood progenitors demonstrate rapid self-renewal and low apoptosis.

Umbilical cord blood (UCB) provides immediate access to haemopoietic stem/progenitor cells (HSPC) but low cell number restricts use in full adult bone marrow reconstitution. This study investigated early ex vivo expansion kinetics of UCB AC133+ cells (2-4 x 10(4)/ml), mononuclear cells (MNC, 1-2 x 10(6)/ml) and AC133negative cells (AC133(neg), 2-4 x 10(4)/ml) in stroma-free 8 d liquid culture (fetal bovine serum-supplemented Iscove's-modified Dulbecco's medium (IMDM) with either 'K36EG'[c-Kit ligand, interleukin 3 (IL-3), IL-6, erythropoietin, granulocyte colony-stimulating factor] or 'TPOFL' (thrombopoietin, Flt-3 ligand). Cell enumeration, apoptosis assay and AC133/CD34/CD38 antigen immunophenotyping were performed at d 0, 3, 5 and 8. All three cell populations went through a proliferation lag phase between d 3 and d 5. AC133+ cells recovered better from lag phase with significantly higher fold increase (FI) when compared with MNC and AC133(neg) populations (K36EG FI: 15.04 +/- 5.46; TPOFL FI: 8.59 +/- 2.92, P < 0.05). After 8 d, populations lacking AC133+ cells were significantly more inclined to undergo apoptosis under proliferative conditions (P < 0.01). Also, when compared with K36EG, 8 d TPOFL-expanded AC133+ cells encompassed a significantly higher percentage of AC133+ and CD34+ early HSPC (K36EG: 20.50 +/- 2.36; TPOFL: 47.00 +/- 7.69; P < 0.05). In conclusion, TPOFL synergism demonstrated the potential for AC133+ HSPC ex vivo expansion inducing self-renewal, early HSPC maintenance and promoting cell survival status.

AC133 Antigen↗
PubMed2002

Pegfilgrastim.

Granulocyte colony stimulating factor (G-CSF) has proven efficacy in the prophylaxis of chemotherapy induced neutropenia and is associated with a reduction in the duration of neutropenia, febrile neutropenia, hospitalisation and intravenous antibiotic use. It is an effective mobiliser of peripheral blood progenitor cells and is used in many countries to mobilise and provide a source of stem cells for autologous and allogeneic bone marrow transplantation. The longevity of G-CSF action is limited by its short half-life, necessitating daily injections. Pegfilgrastim (Neulasta, Amgen, Inc.) is a novel form of filgrastim (G-CSF) with a sustained duration of action. Single dose pegfilgrastim has been shown to be as safe and effective as daily filgrastim in reducing the incidence of chemotherapy induced neutropenia. Pegfilgrastim provides clinical and quality of life benefits for patients as a result of its once per cycle administration. It is licenced in the US for use in the prophylaxis and treatment of chemotherapy induced neutropenia. Clinical trials to evaluate its ability to mobilise peripheral blood progenitor cells are ongoing.

Animals↗
PubMedDate not supplied

Clinical evidence of a graft-versus-Hodgkin's-lymphoma effect after reduced-intensity allogeneic transplantation.

BACKGROUND: In patients with multiply relapsed Hodgkin's lymphoma allogeneic stem-cell transplantation has been limited by prohibitive non-relapse-related mortality rates and by a lack of definitive evidence for a therapeutic graft-versus-tumour effect. Therefore, we aimed to assess the graft-versus-tumour effect of reduced-intensity allogeneic transplantation. METHODS: We undertook reduced-intensity transplantation in 49 patients with multiply relapsed Hodgkin's lymphoma, 44 (90%) of whom had progression of disease after previous autologous transplantation (median age 32 years [range 18-51], number of previous treatment courses was five [range 3-8], and time from diagnosis 4.8 years [range 0.6-4.8]). 31 patients had HLA matched donors who were related and 18 had donors who were unrelated. Median follow-up was 967 days (range 102-2232). The primary endpoints were engraftment, toxic effects, non-relapse-related mortality, incidence of graft-versus-host disease (GVHD), and the toxic effects of adjuvant donor-lymphocyte infusion. FINDINGS: All patients engrafted. Eight of 49 (16%) had grade II-IV acute GVHD and seven (14%) had chronic GVHD before donor-lymphocyte infusion. 16 (33%) patients received donor-lymphocyte infusion from 3 months after transplantation for residual disease or progression. Six (38%) of the 16 developed grade II-IV acute GVHD and five developed chronic GVHD. Nine (56%) showed disease responses after infusion (eight complete, one partial). Non-relapse-related mortality was 16.3% at 730 days (7.2% for patients who had related donors vs 34.1% for those with unrelated donors, p=0.0206). Projected 4 year overall and progression-free survival were 55.7% and 39.0%, respectively (62.0% and 41.5% for related donors). INTERPRETATION: These data show the potential for durable responses in patients who have previously had substantial treatment for Hodgkin's lymphoma. The low non-relapse-related mortality suggests the procedure could be undertaken earlier in the course of the disease.

Adolescent↗