The hOCT1 SNPs M420del and M408V alter imatinib uptake and M420del modifies clinical outcome in imatinib-treated chronic myeloid leukemia.

Although the prognosis of chronic myeloid leukemia (CML) patients treated with imatinib is good, many fail to develop an optimal response or lose one. This heterogeneity could be attributed to the presence of human organic cation transporter-1 (hOCT1) single nucleotide polymorphisms (SNPs). In the present study, we analyzed the effect of 23 hOCT1 SNPs on imatinib treatment outcome in newly diagnosed CML patients using MassARRAY sequencing and pyrosequencing. The only SNP associated with outcome was M420del (rs35191146), with patients with the M420del demonstrating an increased probability of imatinib treatment failure. In CML cell lines transfected with M420del and/or M408V, M420del significantly decreased imatinib uptake, but this effect was countered if the M408V (rs628031) SNP was also present. A similar effect was seen for the uptake of the hOCT1 substrates TEA(+) and ASP(+). Finally, apparent hOCT1 mRNA levels were studied using both our earlier primers covering the M420del and another set that did not. Different mRNA expression was observed, explaining the disparity in published data on the prognostic importance of hOCT1 mRNA and highlighting the importance of avoiding common SNP sites in primer design. These data demonstrate that the common M420del SNP can modulate the outcome of imatinib treatment.

Gender and venture capital decision-making: the effects of technical background and social capital on entrepreneurial evaluations.

Research on gender and workplace decision-making tends to address either supply-side disparities between men's and women's human and social capital, or demand-side differences in the status expectations of women and men workers. In addition, this work often relies on causal inferences drawn from empirical data collected on worker characteristics and their workplace outcomes. In this study, we demonstrate how tangible education and work history credentials - typically associated with supply-side characteristics - work in tandem with cultural beliefs about gender to influence the evaluative process that underlies venture capital decisions made in high-growth, high-tech entrepreneurship. Using an experimental design, we simulate funding decisions by venture capitalists (VCs) for men and women entrepreneurs that differ in technical background and the presence of important social ties. We demonstrate the presence of two distinct aspects of VCs' evaluation: that of the venture and that of the entrepreneur, and find that the gender of the entrepreneur influences evaluations most when the person, rather than the venture, is the target of evaluation. Technical background qualifications moderate the influence of gendered expectations, and women receive more of a payoff than men from having a close contact to the evaluating VC. We discuss the implications for future research on gender and work.

Early depressive symptoms and disability accrual in Multiple Sclerosis: a UK MS Register study.

Understanding the associations and potential drivers of long-term disability in Multiple Sclerosis (MS) is of clinical and prognostic value. Previous data have suggested a link between depression and disability accrual in MS. We aimed to determine whether depression in early MS predicts subsequent accrual of disability. Using data from the UK MS Register, we identified individuals with and without symptoms of depression and anxiety close to disease onset. We used Cox proportional hazards regression to evaluate whether early depressive or anxiety symptoms predict subsequent physical disability worsening, measured using the Expanded Disability Status Scale (EDSS). We analysed data from 862 people with MS of whom 134 (15.5%) reached an EDSS of ≥ 6.0. Early depressive symptoms were associated with an increased risk of reaching an EDSS of 6.0 (HR 2.42, 95% CI 1.49-3.95, p < 0.001), however this effect dissipated when adjusting for baseline EDSS (HR 1.40, 95% CI 0.84-2.32, p = 0.2). These data suggest that early depressive symptoms in MS are associated with subsequent disability accrual, but are likely the result of disability rather than its cause.

Effective dasatinib uptake may occur without human organic cation transporter 1 (hOCT1): implications for the treatment of imatinib-resistant chronic myeloid leukemia.

We have previously shown that imatinib uptake into chronic myeloid leukemia (CML) cells is dependent on human organic cation transporter 1 (hOCT1; SLC22A1), and that low hOCT1 expression is an important determinant of clinical outcome to imatinib treatment. We hypothesized that dasatinib might be transported differently than imatinib, possibly accounting for its favorable effects in imatinib-resistant patients. (14)C-dasatinib uptake was greater in KCL22-transfected cells with pcDNA3-hOCT1 plasmid (high hOCT1-expressing cells) than in control cells (P = .02). However, hOCT inhibitors did not decrease dasatinib uptake into either control or primary cells, in contrast to their block on imatinib uptake. Dasa-tinib decreased the level of phosphorylated CrkL to 49.9% in control and 40.3% in high hOCT1-expressing cells. Dasa-tinib efflux was investigated in confluent ABCB1-transfected MDCKII cell monolayers. Both dasatinib and imatinib were transported from the basal to the apical layer, indicating that they were transported by ABCB1, which was confirmed using the ABCB1 inhibitor PSC833 (P = .001 and P < .001, respectively). Compared with imatinib, dasatinib achieved superior intracellular levels and BCR-ABL suppression even in cells with low or blocked hOCT1. Efflux of dasatinib and imatinib appear similar via ABCB1. Dasatinib may therefore offer an advantage over imatinib in patients with low hOCT1 expression.

Implementing a quality improvement programme in a locality mental health service.

In healthcare, quality improvement (QI) involves organisations and staff aiming to continually improve how they work, quality of care and patient outcomes. In the summer of 2017, a QI programme was endorsed and supported by the clinical director and the head of nursing in the mental health delivery unit of a Welsh health board. This article describes the process of introducing the QI programme in one of the three locality mental health services in the health board. A QI board was established to oversee the process and provide support, and QI champions were introduced to develop QI skills and capacity among staff across the locality mental health service's clinical teams. Improvements made by the QI champions during the first 12 months of the programme included: increased accuracy of electronic transfers of care; reduced readmission rates; the co-production of guides to engage ward-based staff; and the creation of digital staff stories. The authors also reflect on the challenges they experienced in introducing the QI programme and make recommendations for organisations and senior nurses for implementing such programmes effectively.

Serotonin re-uptake transporter gene polymorphisms are associated with imatinib-induced diarrhoea in chronic myeloid leukaemia patients.

Tyrosine kinase inhibitors (TKIs), the treatment of choice for chronic myeloid leukaemia (CML), can cause lower gastrointestinal (GI) toxicity which is manifested as diarrhoea. The mechanisms are not fully understood. The enteroendocrine signalling compound, serotonin (5-HT), is important for regulating peristaltic motion, fluid secretion and visceral hypersensitivity in the GI tract, and has been implicated in diseases such as irritable bowel syndrome. In this study, we have evaluated whether TKI-induced diarrhoea may be related to variation in the serotonin re-uptake transporter (SERT) gene. CML patients with and without diarrhoea on the SPIRIT2 trial (imatinib, n = 319; and dasatinib, n = 297) were genotyped for the promoter 5-HTTLPR, intron 2 VNTR and rs25531 polymorphisms by PCR-based methods. Diarrhoea was more prevalent in imatinib, than in dasatinib treated patients (P = 0.015), which when stratified by gender was seen to be driven by female patients (P = 0.036). Logistic regression analysis revealed that age, and the dominant HTTLPR with the rs25531 single nucleotide polymorphism (SNP) model, explained the occurrence of diarrhoea in ~10% of imatinib-treated female CML patients. These data suggest SERT polymorphisms influence imatinib-induced diarrhoea but not that of dasatinib.

Chronic myeloid leukemia patients with the e13a2 BCR-ABL fusion transcript have inferior responses to imatinib compared to patients with the e14a2 transcript.

BACKGROUND: Chronic myeloid leukemia is characterized by a reciprocal translocation between chromosomes 9 and 22, creating the fusion gene BCR-ABL. The clinical significance of the type of BCR-ABL transcript in newly diagnosed patients in chronic phase treated with imatinib 400 mg from initial diagnosis remains unknown. DESIGN AND METHODS: We analyzed the clinical outcome of 78 newly diagnosed chronic phase patients, aged 16 or over, treated with imatinib 400 mg. Of these, 71 expressed either e13a2 or e14a2 transcripts. BCR-ABL transcripts were assayed by quantitative real-time polymerase chain reaction. RESULTS: After 12 months of treatment, 54% of the e14a2 patients had achieved a complete cytogenetic response, compared to 25% of the e13a2 patients (p=0.01). Kaplan-Meier analysis of the time to achieve complete cytogenetic response revealed that e14a2 patients had more rapid response rates, compared to e13a2 patients (p=0.006). e14a2 patients had a higher event-free survival rate in the first 12 months of treatment, although overall survival did not differ significantly between the patients with the two types of transcript. Human organic cation transporter protein 1 mRNA levels did not differ between the patients with the two types of transcript. The pre-treatment pCrKL/CrKL ratio (a surrogate marker of BCR-ABL tyrosine kinase activity) was higher in patients with e13a2 transcripts than in those with e14a2 (p=0.017). CONCLUSIONS: Patients expressing the e14a2 transcript type have a higher rate and more rapid complete cytogenetic responses than e13a2-expressing patients, which may be due to higher BCR-ABL tyrosine kinase activity. Knowledge of the transcript type may yield additional prognostic information, although this requires testing on larger datasets.

Towards better models and mechanistic biomarkers for drug-induced gastrointestinal injury.

Adverse drug reactions affecting the gastrointestinal (GI) tract are a serious burden on patients, healthcare providers and the pharmaceutical industry. GI toxicity encompasses a range of pathologies in different parts of the GI tract. However, to date no specific mechanistic diagnostic/prognostic biomarkers or translatable pre-clinical models of GI toxicity exist. This review will cover the current knowledge of GI ADRs, existing biomarkers and models with potential application for toxicity screening/monitoring. We focus on the current gaps in our knowledge, the potential opportunities and recommend that a systematic approach is needed to identify mechanism-based GI biomarkers with potential for clinical translation.

Competitive nodulation blocking of cv. Afghanistan pea is related to high levels of nodulation factors made by some strains of Rhizobium leguminosarum bv. viciae.

Cultivar Afghanistan peas are resistant to nodulation by many strains of Rhizobium leguminosarum bv. viciae but are nodulated by strain TOM, which carries the host specificity gene nodX. Some strains that lack nodX can inhibit nodulation of cv. Afghanistan by strain TOM. We present evidence that this "competitive nodulation-blocking" (Cnb) phenotype may result from high levels of Nod factors inhibiting nodulation of cv. Afghanistan peas. The TOM nod gene region (including nodX) is cloned on pIJ1095, and strains (including TOM itself) carrying pIJ1095 nodulate cv. Afghanistan peas very poorly but can nodulate other varieties normally. The presence of pIJ1095, which causes increased levels of Nod factor production, correlates with Cnb. Nodulation of cv. Afghanistan by TOM is also inhibited by a cloned nodD gene that increases nod gene expression and Nod factor production. Nodulation of cv. Afghanistan can be stimulated if nodD on pIJ1095 is mutated, thus severely reducing the level of Nod factor produced. Repression of nod gene expression by nolR eliminates the Cnb phenotype and can stimulate nodulation of cv. Afghanistan. Addition of Nod factors to cv. Afghanistan roots strongly inhibits nodulation. The Cnb+ strains and added Nod factors inhibit infection thread initiation by strain TOM. The sym2A allele determines resistance of cv. Afghanistan to nodulation by strains of R. leguminosarum bv. viciae lacking nodX. We tested whether sym2A is involved in Cnb by using a pea line carrying the sym2A region introgressed from cv. Afghanistan; nodulation in the introgressed line was inhibited by Cnb+ strains. Therefore, the sym2A region has an effect on Cnb, although another locus (or loci) may contribute to the stronger Cnb seen in cv. Afghanistan.

Lamotrigine is a substrate for OCT1 in brain endothelial cells.

The mechanisms that underpin the passage of lamotrigine at the blood-brain barrier to its site of action in the brain is poorly understood. Lamotrigine has been postulated to be delivered to its site of action in the brain favourably despite its physicochemical properties. The aim of this study was to investigate the transport of lamotrigine in an in-vitro model of the BBB. In this study, lamotrigine was found to have a distribution coefficient of 0 at pH 7.4 indicating that it was not highly lipophilic. Human brain endothelial cells (hCMEC/D3) were used to probe the interaction of lamotrigine with drug transporters. The uptake of lamotrigine into hCMEC/D3 cells was found to be an active process (K(m) = 62 ± 14 µM; V(max) = 385 ± 30 pmol/min/million cells). Furthermore, use of a panel of transporter inhibitors indicated that this active uptake was mediated by organic cation transporter 1 (OCT1). OCT1 mRNA and protein were shown to be expressed in hCMEC/D3 cells. KCL22 cells overexpressing OCT1 were then used to validate these findings. Lamotrigine was confirmed to be a substrate and inhibitor in OCT1-transfected KCL22 cells. A putative pharmacokinetic drug-drug interaction (DDI) between quetiapine and lamotrigine was recently reported in patients and we show here that quetiapine is a potent inhibitor of the OCT1-mediated transport of lamotrigine. This is the first time that a specific influx transporter has been shown to transport lamotrigine. The clinical implications of these findings with respect to the efficacy of lamotrigine and its potential for DDI require further investigation.

Simultaneous determination of nilotinib, imatinib and its main metabolite (CGP-74588) in human plasma by ultra-violet high performance liquid chromatography.

We describe a high performance liquid chromatography (HPLC) method that separates two of the currently licenced tyrosine kinase inhibitors (TKIs); nilotinib (AMN107, Tasigna) and imatinib (STI571, Glivec), together with its main metabolite, CGP-74588, from human plasma. After solid phase extraction the drug mix was separated through a Gemini C6-phenyl column (150 mm x 4.6mm, i.d.; 5 microm) (Phenomenex), UK) under isocratic mobile phase conditions of methanol:50mM ammonium acetate (pH 8) (65:35, v/v) with ultra-violet (UV) detection at 260 nm wavelength. For all compounds the intra-day coefficient of variation and bias were <3% and <5% respectively; and inter-day were <4% and <9%. This simple and novel method may be used to quantify levels of TKIs when used alone or in combination with drug treatments for clinical samples.

Pharmacologic markers and predictors of responses to imatinib therapy in patients with chronic myeloid leukemia.

Clinical resistance to imatinib often occurs in the absence of a mutation in the BCR-ABL kinase domain. Imatinib is transported out of cells by the efflux transporter ABCB1 (MDR1, whose product is p-glycoprotein). By contrast, the influx transporter, human organic cation transporter 1 (hOCT1) (also known as SLC22A1), transports imatinib into cells. Recent studies have identified that patients with low expression or activity of hOCT1 have a lower probability of achieving a cytogenetic or molecular remission. Prospective studies are currently investigating whether early trends in transporter expression can be used to guide treatment decisions. Plasma imatinib levels are higher in patients responding well to treatment, and may be useful in patients with suboptimal response or dubious compliance. Uptake of the second generation tyrosine kinase inhibitors, dasatinib and nilotinib, is less dependent upon hOCT1. These two drugs may therefore achieve adequate intracellular concentrations even in patients with low hOCT1 expression.