The chronic myeloid leukemia stem cell: stemming the tide of persistence

Chronic myeloid leukaemia (CML) is caused by the acquisition of the tyrosine kinase BCR-ABL1 in a haemopoietic stem cell (HSC), transforming it into a leukaemic stem cell (LSC) that self-renews, proliferates and differentiates to give rise to a myeloproliferative disease. While tyrosine kinase inhibitors (TKI) that target the kinase activity of BCR-ABL1 have transformed CML from a once fatal disease to a manageable one for the vast majority of patients, only ~10% of those who present in chronic phase (CP) can discontinue TKI treatment and maintain a therapy-free remission. Strong evidence now shows that CML LSC are resistant to the effects of TKIs and they persist in all patients on long-term therapy, where they may promote acquired TKI resistance, drive relapse or disease progression and inevitably represent a bottleneck to cure. Since their discovery in patients almost two decades ago, CML LSC have become a well-recognised exemplar of the cancer stem cell and have been characterised extensively with the aim of developing new curative therapeutic approaches based on LSC eradication. This review summarises our current understanding of many of the pathways and mechanisms that promote the survival of the CP CML LSC and how they can be a source of new gene coding mutations that impact in the clinic. We also review recent pre-clinical approaches that show promise to eradicate the LSC, and future challenges on the path to cure

Lifting the differentiation embargo

Effective differentiation therapy for acute myeloid leukemia (AML) has been restricted to a small subset of patients with one defined genetic abnormality. Using an unbiased small molecule screen, Sykes et al. now identify a mechanism of de-repression of differentiation in several models of AML driven by distinct genetic drivers

VLE for Dual Career Sports Officials Undertaking a Part-time MA in Personal and Professional Development Nick Holyoake

Advantages and disadvantages of using a Virtual Learning Environment to support part-time students impacted by significantly reduced opportunity for face-to-face contact. Suggestions on tackling student disengagement from the virtual learning interface by introducing a range of activities specifically designed to enhance the remote student experience

Validating a network hub in leukaemia stem cells

No abstract available

A national study of gastrointestinal parasites infecting dogs and cats in Australia

Despite the popularity of companion animal ownership in Australia, recent and comprehensive information with regard to the prevalence, epidemiology and public health significance associated with gastrointestinal parasites of pet dogs and cats in Australia is largely lacking. The primary aims of this study were to close this knowledge gap and to evaluate the veterinarian’s perception, awareness and knowledge of GI parasites in their locality, from a veterinary and public health stand-point. This included sourcing information with regard to commonly recommended deworming protocols. The awareness of pet owners regarding parasitic zoonoses and the degree of education provided to them by veterinarians was also determined. A total of 1400 canine and 1063 feline faecal samples were collected from veterinary clinics and refuges from across Australia. The overall prevalence of gastrointestinal parasites in dogs and cats was 23.9% (CI 21.7-26.1) and 18.4% (CI 16.1-20.7), respectively. Overall Giardia duodenalis was the most prevalent parasite in dogs (9.3%, CI 7.8-10.8) followed by hookworm (6.7%, CI 5.4-8.0). Isospora felis was the most prevalent parasite in cats (5.6%, CI 4.2-7.0), followed by Toxocara cati (3.2%, CI 2.1-4.3). A highly sensitive and species-specific PCR-RFLP technique was utilized to differentiate the various hookworm species which can infect dogs and cats directly from eggs in faeces. Ancylostoma ceylanicum was detected for the first time in Australia in 10.9% of the dogs found positive for hookworm. This was a significant finding in terms of the zoonotic risk associated with this parasite. The zoonotic potential of Giardia and Cryptosporidium was investigated by genetically characterising isolates recovered from dogs and cats. All but one of the Giardia isolates successfully genotyped were host specific, indicating a low zoonotic risk. It was hypothesized that the lack of zoonotic Giardia Assemblages was a consequence of there being a low prevalence of Giardia in the human population. The Cryptosporidium recovered from dogs and cats was determined to be Cryptosporidium canis and Cryptosporidium felis respectively, a finding which supports growing evidence that Cryptosporidium in companion animals is of limited public health significance to healthy people. Very few of the veterinarians surveyed in the study routinely discussed the zoonotic potential of pet parasites with clients. Most of the veterinarians recommended the regular prophylactic administration of anthelmintics throughout a pet’s life. The low national prevalence of GI parasites reported is most likely a consequence of the widespread use of anthelmintics by pet owners. There is an over-reliance on anthelmintics by veterinarians to prevent and control parasites and their zoonotic risk. This has resulted in veterinarians becoming complacent about educating pet owners about parasites. A combination of routinely screening faecal samples for parasites, strategic anthelmintic regimes and improved pet owner education is recommended for the control of GI parasites in pet dogs and cats in Australia

Inhibition of MDR1 does not sensitize primitive chronic myeloid leukemia CD34⁺ cells to imatinib

<p><b>Objective:</b> To investigate the interaction of imatinib mesylate (IM) with the clinically relevant adenosine triphosphate-binding cassette efflux transporter MDR1 (ABCB1) in cells from patients with chronic myeloid leukemia (CML) and to explore whether inhibition of this transporter would improve IM's efficacy in the elimination of CML CD34<sup>+</sup> cells by increasing cell-associated drug accumulation.</p> <p><b>Materials and Methods:</b> Cells from newly diagnosed chronic-phase CML patients were harvested by leukapheresis and enriched to >95% CD34<sup>+</sup>. Expression of the transporter gene MDR1 was performed by quantitative reverse transcription polymerase chain reaction. Interaction of IM with MDR1 was analyzed by substrate (rhodamine 123) displacement assay. Cell-associated levels of IM in CML CD34<sup>+</sup> cells were measured by high-pressure liquid chromatography. Intracellular phospho-CrkL levels, apoptosis in total CML CD34<sup>+</sup> cells and high-resolution tracking of cell division were assayed by flow cytometry.</p> <p><b>Results:</b> Measurements of cell-associated IM uptake showed significantly lower drug levels in CD34<sup>+</sup> cells, particularly the CD38<sup>-</sup> subpopulation, as compared to IM-sensitive K562 cells. MDR1 was expressed at low level and dye efflux studies demonstrated very little MDR1 activity in CML CD34<sup>+</sup> cells. Furthermore, combination treatment of primitive CML cells with IM and the MDR1 inhibitor PSC833 did not result in elevated cell-associated IM levels. Although we observed slightly enhanced cytostasis with IM when combined with PSC833, this was independent of BCR-ABL inhibition because no associated decrease in phospho-CrkL was observed.</p> <p><b>Conclusions:</b> Our findings demonstrate that inhibition of MDR1 neither enhances the effect of IM against BCR-ABL activity, nor significantly potentiates IM's efficiency in eliminating primitive CML cells.</p&gt

Analysis of imatinib in bone marrow and plasma samples of chronic myeloid leukaemia patients using solid phase extraction LC-ESI-MS

The LC-ESI-MS was developed and validated for the analysis of imatinib in plasma and bone marrow samples using deuterated imatinib (D(8)-IM) as an internal standard. The biological samples were extracted using Strata-X-C SPE cartridges and separated on C<sub>8</sub> column (50 x 3 mm, 3 µm), and methanol: 0.1% formic acid (70:30) was delivered at the rate of 0.7 ml/min as a mobile phase. Imatinib was quantified in samples by monitoring the ions m/z 494.3 for imatinib and 502.3 for D<sub>8</sub>-imatinib on mass spectrometer. The method was linear in the concentration range of 1-1500 ng/250 µl in spiked human plasma samples and limit of quantification was 5 ng/mL. Inter-day and intra-day variations in spiked human plasma spiked with 50, 250 and 500 ng /mL were less than 3.16%. The repeatability and reproducibility and other parameters of the methods were also validated. The method was employed for the analysis of the imatinib in human plasma and bone marrow samples. The drug levels in bone marrow and plasma samples were correlated to the degree of cytogenetic response. No significant difference of imatinib level between blood and bone marrow in IM-treated patients dosed to steady state was observed

The culture of conservation : an ethnographic interpretation of the re-use of historic urban industrial buildings in England

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Cooperation of imipramine blue and tyrosine kinase blockade demonstrates activity against chronic myeloid leukemia

The use of tyrosine kinase inhibitors (TKI), including nilotinib, has revolutionized the treatment of chronic myeloid leukemia (CML). However current unmet clinical needs include combating activation of additional survival signaling pathways in persistent leukemia stem cells after long-term TKI therapy. A ubiquitous signaling alteration in cancer, including CML, is activation of reactive oxygen species (ROS) signaling, which may potentiate stem cell activity and mediate resistance to both conventional chemotherapy and targeted inhibitors. We have developed a novel nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, imipramine blue (IB) that targets ROS generation. ROS levels are known to be elevated in CML with respect to normal hematopoietic stem/progenitor cells and not corrected by TKI. We demonstrate that IB has additive benefit with nilotinib in inhibiting proliferation, viability, and clonogenic function of TKI-insensitive quiescent CD34+ CML chronic phase (CP) cells while normal CD34+ cells retained their clonogenic capacity in response to this combination therapy in vitro. Mechanistically, the pro-apoptotic activity of IB likely resides in part through its dual ability to block NF-κB and re-activate the tumor suppressor protein phosphatase 2A (PP2A). Combining BCR-ABL1 kinase inhibition with NADPH oxidase blockade may be beneficial in eradication of CML and worthy of further investigation