71 research outputs found

    Hydroxyurea synergizes with valproic acid in wild-type p53 acute myeloid leukaemia

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    Palliative care in acute myeloid leukaemia (AML) is inadequate. For elderly patients, unfit for intensive chemotherapy, median survival is 2–3 months. As such, there is urgent demand for low-toxic palliative alternatives. We have repositioned two commonly administered anti-leukaemia drugs, valproic acid (VPA) and hydroxyurea (HU), as a combination therapy in AML. The anti-leukemic effect of VPA and HU was assessed in multiple AML cell lines confirming the superior anti-leukemic effect of combination therapy. Mechanistic studies revealed that VPA amplified the ability of HU to slow S-phase progression and this correlated with significantly increased DNA damage. VPA was also shown to reduce expression of the DNA repair protein, Rad51. Interestingly, the tumour suppressor protein p53 was revealed to mitigate cell cycle recovery following combination induced arrest. The efficacy of combination therapy was validated in vivo. Combination treatment increased survival in OCI-AML3 and patient-derived xenograft mouse models of AML. Therapy response was confirmed by optical imaging with multiplexed near-infrared labelled antibodies. The combination of HU and VPA indicates significant potential in preclinical models of AML. Both compounds are widely available and well tolerated. We believe that repositioning this combination could significantly enhance the palliative care of patients unsuited to intensive chemotherapy.publishedVersio

    Tyrosine kinase inhibitors and interferon‐α increase tunneling nanotube (TNT) formation and cell adhesion in chronic myeloid leukemia (CML) cell lines (

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    Chronic myeloid leukemia (CML) is a stem cell disease of the bone marrow where mechanisms of inter‐leukemic communication and cell‐to‐cell interactions are proposed to be important for optimal therapy response. Tunneling nanotubes (TNTs) are novel intercellular communication structures transporting different cargos with potential implications in therapy resistance. Here, we have investigated TNTs in CML cells and following treatment with the highly effective CML therapeutics tyrosine kinase inhibitors (TKIs) and interferon‐α (IFNα). CML cells from chronic phase CML patients as well as the blast crisis phase cell lines, Kcl‐22 and K562, formed few or no TNTs. Treatment with imatinib increased TNT formation in both Kcl‐22 and K562 cells, while nilotinib or IFNα increased TNTs in Kcl‐22 cells only where the TNT increase was associated with adherence to fibronectin‐coated surfaces, altered morphology, and reduced movement involving β1integrin. Ex vivo treated cells from chronic phase CML patients showed limited changes in TNT formation similarly to bone marrow cells from healthy individuals. Interestingly, in vivo nilotinib treatment in a Kcl‐22 subcutaneous mouse model resulted in morphological changes and TNT‐like structures in the tumor‐derived Kcl‐22 cells. Our results demonstrate that CML cells express low levels of TNTs, but CML therapeutics increase TNT formation in designated cell models indicating TNT functionality in bone marrow derived malignancies and their microenvironment.publishedVersio

    Early response evaluation by single cell signaling profiling in acute myeloid leukemia

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    Aberrant pro-survival signaling is a hallmark of cancer cells, but the response to chemotherapy is poorly understood. In this study, we investigate the initial signaling response to standard induction chemotherapy in a cohort of 32 acute myeloid leukemia (AML) patients, using 36-dimensional mass cytometry. Through supervised and unsupervised machine learning approaches, we find that reduction of extracellular-signal-regulated kinase (ERK) 1/2 and p38 mitogen-activated protein kinase (MAPK) phosphorylation in the myeloid cell compartment 24 h post-chemotherapy is a significant predictor of patient 5-year overall survival in this cohort. Validation by RNA sequencing shows induction of MAPK target gene expression in patients with high phosphoERK1/2 24 h post-chemotherapy, while proteomics confirm an increase of the p38 prime target MAPK activated protein kinase 2 (MAPKAPK2). In this study, we demonstrate that mass cytometry can be a valuable tool for early response evaluation in AML and elucidate the potential of functional signaling analyses in precision oncology diagnostics.Peer reviewe

    Feasibility and effects of preventive home visits for at-risk older people: Design of a randomized controlled trial

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    Abstract Background The search for preventive methods to mitigate functional decline and unwanted relocation by older adults living in the community is important. Preventive home visit (PHV) models use infrequent but regular visits to older adults by trained practitioners with the goal of maintaining function and quality of life. Evidence about PHV efficacy is mixed but generally supportive. Yet interventions have rarely combined a comprehensive (biopsychosocial) occupational therapy intervention protocol with a home visit to older adults. There is a particular need in the USA to create and examine such a protocol. Methods/Design The study is a single-blind randomized controlled pilot trial designed to assess the feasibility, and to obtain preliminary efficacy estimates, of an intervention consisting of preventive home visits to community-dwelling older adults. An occupational therapy-based preventive home visit (PHV) intervention was developed and is being implemented and evaluated using a repeated measures design. We recruited a sample of 110 from a population of older adults (75+) who were screened and found to be at-risk for functional decline. Participants are currently living in the community (not in assisted living or a skilled nursing facility) in one of three central North Carolina counties. After consent, participants were randomly assigned into experimental and comparison groups. The experimental group receives the intervention 4 times over a 12 month follow-up period while the comparison group receives a minimal intervention of mailed printed materials. Pre- and post-intervention measures are being gathered by questionnaires administered face-to-face by a treatment-blinded research associate. Key outcome measures include functional ability, participation, life satisfaction, self-rated health, and depression. Additional information is collected from participants in the experimental group during the intervention to assess the feasibility of the intervention and potential modifiers. Fidelity is being addressed and measured across several domains. Discussion Feasibility indications to date are positive. Although the protocol has some limitations, we expect to learn enough about the intervention, delivery and effects to support a larger trial with a more stringent design and enhanced statistical power. Trial Registration ClinicalTrials.gov ID NCT0098528
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