Iterative sorting reveals CD133+ and CD133- melanoma cells as phenotypically distinct populations

Background: The heterogeneity and tumourigenicity of metastatic melanoma is attributed to a cancer stem cell model, with CD133 considered to be a cancer stem cell marker in melanoma as well as other tumours, but its role has remained controversial. Methods: We iteratively sorted CD133+ and CD133- cells from 3 metastatic melanoma cell lines, and observed tumourigenicity and phenotypic characteristics over 7 generations of serial xeno-transplantation in NOD/SCID mice. Results: We demonstrate that iterative sorting is required to make highly pure populations of CD133+ and CD133- cells from metastatic melanoma, and that these two populations have distinct characteristics not related to the cancer stem cell phenotype. In vitro, gene set enrichment analysis indicated CD133+ cells were related to a proliferative phenotype, whereas CD133- cells were of an invasive phenotype. However, in vivo, serial transplantation of CD133+ and CD133- tumours over 7 generations showed that both populations were equally able to initiate and propagate tumours. Despite this, both populations remained phenotypically distinct, with CD133- cells only able to express CD133 in vivo and not in vitro. Loss of CD133 from the surface of a CD133+ cell was observed in vitro and in vivo, however CD133- cells derived from CD133+ retained the CD133+ phenotype, even in the presence of signals from the tumour microenvironment. Conclusion: We show for the first time the necessity of iterative sorting to isolate pure marker-positive and marker-negative populations for comparative studies, and present evidence that despite CD133+ and CD133- cells being equally tumourigenic, they display distinct phenotypic differences, suggesting CD133 may define a distinct lineage in melanoma

A systematic review of the psychometric properties of self-report research utilization measures used in healthcare

<p>Abstract</p> <p>Background</p> <p>In healthcare, a gap exists between what is known from research and what is practiced. Understanding this gap depends upon our ability to robustly measure research utilization.</p> <p>Objectives</p> <p>The objectives of this systematic review were: to identify self-report measures of research utilization used in healthcare, and to assess the psychometric properties (acceptability, reliability, and validity) of these measures.</p> <p>Methods</p> <p>We conducted a systematic review of literature reporting use or development of self-report research utilization measures. Our search included: multiple databases, ancestry searches, and a hand search. Acceptability was assessed by examining time to complete the measure and missing data rates. Our approach to reliability and validity assessment followed that outlined in the <it>Standards for Educational and Psychological Testing</it>.</p> <p>Results</p> <p>Of 42,770 titles screened, 97 original studies (108 articles) were included in this review. The 97 studies reported on the use or development of 60 unique self-report research utilization measures. Seven of the measures were assessed in more than one study. Study samples consisted of healthcare providers (92 studies) and healthcare decision makers (5 studies). No studies reported data on acceptability of the measures. Reliability was reported in 32 (33%) of the studies, representing 13 of the 60 measures. Internal consistency (Cronbach's Alpha) reliability was reported in 31 studies; values exceeded 0.70 in 29 studies. Test-retest reliability was reported in 3 studies with Pearson's <it>r </it>coefficients > 0.80. No validity information was reported for 12 of the 60 measures. The remaining 48 measures were classified into a three-level validity hierarchy according to the number of validity sources reported in 50% or more of the studies using the measure. Level one measures (n = 6) reported evidence from any three (out of four possible) <it>Standards </it>validity sources (which, in the case of single item measures, was all applicable validity sources). Level two measures (n = 16) had evidence from any two validity sources, and level three measures (n = 26) from only one validity source.</p> <p>Conclusions</p> <p>This review reveals significant underdevelopment in the measurement of research utilization. Substantial methodological advances with respect to construct clarity, use of research utilization and related theory, use of measurement theory, and psychometric assessment are required. Also needed are improved reporting practices and the adoption of a more contemporary view of validity (<it>i.e.</it>, the <it>Standards</it>) in future research utilization measurement studies.</p

Anti-Leukemic Activity of Ubiquinone-Based Compounds Targeting Trans-plasma Membrane Electron Transport

Trans-plasma membrane electron transport (tPMET) is a ubiquinone-dependent cell survival pathway for maintaining intracellular redox homeostasis in rapidly dividing cells. To target this pathway, fifteen ubiquinone-based compounds were designed and synthesized to position at the plasma membrane and disrupt tPMET. We established that quaternary ammonium salt moieties carrying highly hindered, positive electronic charges located to the plasma membrane. A ten-carbon chain linked to these moieties was effective at positioning the redox-active ubiquinone-like function within the lipid bilayer to disrupt tPMET in human leukemic cells (IC₅₀ 9 ± 1 μM). TPMET inhibition alone was not sufficient to induce significant cell death, but positively charged compounds could also enter the cell and disrupt intracellular redox balance, distinct from their effects on mitochondrial electron transport. The synergistic effect of tPMET inhibition plus intracellular redox disruption gave strong antiproliferative activity (IC₅₀ 2 ± 0.2 μM). Positively charged ubiquinone-based compounds inhibit human leukemic cell growth

Anti-Leukemic Activity of Ubiquinone-Based Compounds Targeting Trans-plasma Membrane Electron Transport

Trans-plasma membrane electron transport (tPMET) is a ubiquinone-dependent cell survival pathway for maintaining intracellular redox homeostasis in rapidly dividing cells. To target this pathway, fifteen ubiquinone-based compounds were designed and synthesized to position at the plasma membrane and disrupt tPMET. We established that quaternary ammonium salt moieties carrying highly hindered, positive electronic charges located to the plasma membrane. A ten-carbon chain linked to these moieties was effective at positioning the redox-active ubiquinone-like function within the lipid bilayer to disrupt tPMET in human leukemic cells (IC₅₀ 9 ± 1 μM). TPMET inhibition alone was not sufficient to induce significant cell death, but positively charged compounds could also enter the cell and disrupt intracellular redox balance, distinct from their effects on mitochondrial electron transport. The synergistic effect of tPMET inhibition plus intracellular redox disruption gave strong antiproliferative activity (IC₅₀ 2 ± 0.2 μM). Positively charged ubiquinone-based compounds inhibit human leukemic cell growth

Perfluorocarbon emulsions radiosensitise brain tumors in carbogen breathing mice with orthotopic GL261 gliomas.

BackgroundTumour hypoxia limits the effectiveness of radiation therapy. Delivering normobaric or hyperbaric oxygen therapy elevates pO2 in both tumour and normal brain tissue. However, pO2 levels return to baseline within 15 minutes of stopping therapy.AimTo investigate the effect of perfluorocarbon (PFC) emulsions on hypoxia in subcutaneous and intracranial mouse gliomas and their radiosensitising effect in orthotopic gliomas in mice breathing carbogen (95%O2 and 5%CO2).ResultsPFC emulsions completely abrogated hypoxia in both subcutaneous and intracranial GL261 models and conferred a significant survival advantage orthotopically (Mantel Cox: p = 0.048) in carbogen breathing mice injected intravenously (IV) with PFC emulsions before radiation versus mice receiving radiation alone. Carbogen alone decreased hypoxia levels substantially and conferred a smaller but not statistically significant survival advantage over and above radiation alone.ConclusionIV injections of PFC emulsions followed by 1h carbogen breathing, radiosensitises GL261 intracranial tumors

Additional file 2: Figure S1. of Iterative sorting reveals CD133+ and CD133- melanoma cells as phenotypically distinct populations

CD133+ and CD133- cells have similar frequency of tumour-initiating cells. Serial dilution of CD133+ and CD133- cell used in sub-cutaneous xenograft. Square, 105 cells; triangle, 104 cells; circle, 103 cells. Average (+/- SD) tumour volume measured over time, 3–5 mice/group. Data representative of 2 independent replicate experiments (PDF 203 kb

Antitumor Activity of Bis-indole Derivatives

none16noneA. Andreani; S. Burnelli; M. Granaiola; A. Leoni; A. Locatelli; R. Morigi; M. Rambaldi; L. Varoli; L. Landi; C. Prata; M. V. Berridge; C. Grasso; H-H. Fiebig; G. Kelter; A. M. Burger; M. W. KunkelA. Andreani; S. Burnelli; M. Granaiola; A. Leoni; A. Locatelli; R. Morigi; M. Rambaldi; L. Varoli; L. Landi; C. Prata; M. V. Berridge; C. Grasso; H-H. Fiebig; G. Kelter; A. M. Burger; M. W. Kunke

Irradiation setup for whole brain irradiation of mice.

<p>(A) The mouse is anaesthetized and positioned in a Falcon tube (B) inside a 2 cm thick lead shielding device (C) inside plastic rings (D) inside the aluminium cylinder in the Gammacell 3000 Elan irradiator. (E) Diagrammatic representation of the irradiation setup. This setup allowed us only to do whole brain irradiation; we could not irradiate subcutaneous tumors.</p