Targeting Wnt-driven cancer through the inhibition of Porcupine by LGK974.

Wnt signaling is one of the key oncogenic pathways in multiple cancers, and targeting this pathway is an attractive therapeutic approach. However, therapeutic success has been limited because of the lack of therapeutic agents for targets in the Wnt pathway and the lack of a defined patient population that would be sensitive to a Wnt inhibitor. We developed a screen for small molecules that block Wnt secretion. This effort led to the discovery of LGK974, a potent and specific small-molecule Porcupine (PORCN) inhibitor. PORCN is a membrane-bound O-acyltransferase that is required for and dedicated to palmitoylation of Wnt ligands, a necessary step in the processing of Wnt ligand secretion. We show that LGK974 potently inhibits Wnt signaling in vitro and in vivo, including reduction of the Wnt-dependent LRP6 phosphorylation and the expression of Wnt target genes, such as AXIN2. LGK974 is potent and efficacious in multiple tumor models at well-tolerated doses in vivo, including murine and rat mechanistic breast cancer models driven by MMTV-Wnt1 and a human head and neck squamous cell carcinoma model (HN30). We also show that head and neck cancer cell lines with loss-of-function mutations in the Notch signaling pathway have a high response rate to LGK974. Together, these findings provide both a strategy and tools for targeting Wnt-driven cancers through the inhibition of PORCN.

Therapy for hepatitis C virus infection increases survival of patients with pretreatment anemia.

BACKGROUND & AIMS: Individuals with chronic hepatitis C virus (HCV) infection and pretreatment anemia are less likely to begin and complete a full course of treatment for HCV. However, among those who are treated for HCV infection, the effect of treatment on mortality is not clear. METHODS: We performed a retrospective analysis of 200,139 HCV-infected veterans using data from the Electronically Retrieved Cohort of Hepatitis C-Infected veterans (2001-2008). The effects of treatment and treatment duration on survival were compared based on data from 1820 treated and 27,690 untreated anemic HCV-infected veterans. The association between HCV treatment and mortality was estimated using the Cox proportional hazard models, with adjustments for potential confounders. The main outcome was all-cause mortality. RESULTS: In multivariable analysis, pretreatment anemia was associated significantly with African American race (odds ratio [OR], 2.03; 95% confidence interval [CI], 1.95-2.11), chronic kidney disease (OR, 3.36; 95% CI, 3.23-3.51), and decompensated liver disease (OR, 3.69; 95% CI, 3.53-3.86). All-cause mortality for treated, anemic, HCV-infected veterans was lower (54.2 per 1000 person-years; 95% CI, 49.2-59.7 per 1000 person years) than for untreated, anemic HCV-infected veterans (146.8 per 1000 person-years; 95% CI, 144.2-149.4 per 1000 person-years). The adjusted hazard ratio for treatment of HCV in anemic veterans was 0.45 (95% CI, 0.39-0.51), which was reduced after exclusion of comorbidities (hazard ratio, 0.28; 95% CI, 0.22-0.37). CONCLUSIONS: Based on a retrospective analysis of a veterans database, HCV therapy increases survival rates of individuals with pretreatment anemia. Additional studies are needed to determine strategies to increase rates of HCV therapy for this group.

Prevalence of 25-hydroxyvitamin D deficiency in subgroups of elderly persons with anemia: association with anemia of inflammation.

Anemia and vitamin D deficiency are conditions that both result in significant morbidity and increase with age. The potential relationship between them remains poorly understood, particularly in the elderly. We used the Third National Health and Nutrition Examination Survey to examine the association of vitamin D deficiency with anemia subtypes in persons aged ≥ 60 years. Vitamin D deficiency was defined as serum levels < 20 ng/mL, and anemia was defined according to World Health Organization criteria. Vitamin D deficiency was associated with anemia prevalence independent of age, sex, or race/ethnicity (odds ratio, 1.47; 95% confidence interval, 1.06-2.05; P = .02) and varied significantly by anemia subtype (P overall = .003). The prevalence of vitamin D deficiency was 33.3% in the nonanemic population, 56% in anemia of inflammation (AI; P = .008), and 33.0% in unexplained anemia (P = .55). Non-Hispanic blacks had a 7-fold increased risk of AI compared with whites, and this was partially attenuated after adjusting for vitamin D deficiency. These data show that vitamin D deficiency is associated with specific subtypes of anemia in the elderly, especially in those with AI. Vitamin D may suppress inflammatory pathways, and studies to determine whether vitamin D supplementation ameliorates AI are warranted.

A polymorphism in the leptin gene promoter is associated with anemia in patients with HIV disease.

To study factors associated with anemia and its effect on survival in HIV-infected persons treated with modern combined antiretroviral therapy (cART), we characterized the prevalence of anemia in the Veterans Aging Cohort Study (VACS) and used a candidate gene approach to identify proinflammatory gene single nucleotide polymorphisms (SNPs) associated with anemia in HIV disease. The study comprised 1597 HIV(+) and 865 HIV(-) VACS subjects with DNA, blood, and annotated clinical data available for analysis. Anemia was defined according to World Health Organization criteria (hemoglobin < 13 g/dL and < 12 g/dL in men and women, respectively). The prevalence of anemia in HIV(+) and HIV(-) subjects was 23.1% and 12.9%, respectively. Independent of HIV status, anemia was present in 23.4% and 8% in blacks and whites, respectively. Analysis of our candidate genes revealed that the leptin -2548 G/A SNP was associated with anemia in HIV(+), but not HIV(-), patients, with the AA and AG genotypes significantly predicting anemia (P < .003 and P < .039, respectively, logistic regression). This association was replicated in an independent cohort of HIV(+) women. Our study provides novel insight into the association between genetic variability in the leptin gene and anemia in HIV(+) individuals.

Does an index composed of clinical data reflect effects of inflammation, coagulation, and monocyte activation on mortality among those aging with HIV?

BACKGROUND: When added to age, CD4 count and human immunodeficiency virus type 1 (HIV-1) RNA alone (Restricted Index), hemoglobin, FIB-4 Index, hepatitis C virus (HCV), and estimated glomerular filtration rate improve prediction of mortality. Weighted and combined, these 7 routine clinical variables constitute the Veterans Aging Cohort Study (VACS) Index. Because nonroutine biomarkers of inflammation (interleukin 6 [IL-6]), coagulation (D-dimer), and monocyte activation (sCD14) also predict mortality, we test the association of these indices and biomarkers with each other and with mortality. METHODS: Samples from 1302 HIV-infected veterans on antiretroviral therapy were analyzed. Indices were calculated closest to date of collection. We calculated Spearman correlations stratified by HIV-1 RNA and HCV status and measured association with mortality using C statistics and net reclassification improvement (NRI). RESULTS: Of 1302 subjects, 915 had HIV-1 RNA <500 copies/mL and 154 died. The VACS Index was more correlated with IL-6, D-dimer, and sCD14 than the Restricted Index (P < .001). It was also more predictive of mortality (C statistic, 0.76; 95% confidence interval [CI], .72-.80) than any biomarker (C statistic, 0.66-0.70) or the Restricted Index (C statistic, 0.71; 95% CI, .67-.75). Compared to the Restricted Index alone, NRI resulted from incremental addition of VACS Index components (10%), D-dimer (7%), and sCD14 (4%), but not from IL-6 (0%). CONCLUSIONS: Among HIV-infected individuals, independent of CD4, HIV-1 RNA, and age, hemoglobin and markers of liver and renal injury are associated with inflammation. Addition of D-dimer and sCD14, but not IL-6, improves the predictive accuracy of the VACS Index for mortality.

Resveratrol ameliorates TNFα-mediated suppression of erythropoiesis in human CD34(+) cells via modulation of NF-κB signalling.

Overexpression of pro-inflammatory cytokines, including tumour necrosis factor alpha (TNFα), has been implicated in the pathogenesis of anaemia of inflammation. TNFα suppresses erythroid colony formation via both direct and indirect effects on haematopoietic progenitors, often involving activation of nuclear factor (NF)-κB signalling resulting in downregulation of transcription factors critical for erythropoiesis. There is a dearth of effective and safe therapies for many patients with inflammatory anaemia. Resveratrol is a flavanol found in red wine grapes that possesses potent anti-inflammatory properties, but studies of its impact on human erythropoiesis have proven contradictory. We investigated whether resveratrol ameliorates TNFα-mediated suppression of erythropoiesis in human CD34(+) haematopoietic progenitors. We found that resveratrol partially reverses the erythroid suppressive effects of TNFα, leading to significant recovery in burst forming unit-erythroid colony formation in human CD34(+) cells. CD34(+) cells pre-incubated with resveratrol for 72 h in the presence of TNFα inhibited NF-κB activation via decreased NF-κB nuclear localization without altering total NF-κB protein levels and independent of IκB degradation. Resveratrol also significantly restored the baseline expression of erythroid transcription factors NFE2 and the GATA1/GATA2 ratio in CD34(+) cells treated with TNFα. In conclusion, resveratrol may inhibit TNFα-mediated NF-κB activation and promote erythropoiesis in primary human CD34(+) cells.

Design and validation of a high-throughput matrix-assisted laser desorption ionization time-of-flight mass spectrometry method for quantification of hepcidin in human plasma.

Disorders of iron metabolism affect over a billion people worldwide. The circulating peptide hormone hepcidin, the central regulator of iron distribution in mammals, holds great diagnostic potential for an array of iron-associated disorders, including iron loading (ß-thalassemia), iron overload (hereditary hemochromatosis), and iron deficiency diseases. We describe a novel high-throughput matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry assay for quantification of hepcidin in human plasma. This assay involves enrichment using a functionalized MALDI chip, a novel solvent-detergent precipitation buffer, and quantification using a stable isotope labeled internal standard. The linear range of hepcidin in plasma was 1-120 nM, with a low limit of quantification (LOQ) (1 nM), high accuracy (<15% relative error (RE)), and high precision (intraday average 5.52-18.48% coefficient of variation (CV) and interday 9.32-14.83% CV). The assay showed strong correlation with an established hepcidin immunoassay (Spearman; R(2) = 0.839 n = 93 ethylenediaminetetraacetic acid (EDTA) plasma). A collection of normal healthy pediatric samples (range 3.8-32.5 ng/mL; mean 12.9 ng/mL; n = 119) showed significant differences from an adult collection (range 1.8-48.7 ng/mL; mean 16.1 ng/mL; n = 95; P = 0.0096). We discuss these preliminary reference ranges and correlations with additional parameters in light of the utility and limitations of hepcidin measurements as a stand-alone diagnostic and as a tool for therapeutic intervention.

Therapeutic Efficacy of Combined JAK1/2, Pan-PIM, and CDK4/6 Inhibition in Myeloproliferative Neoplasms.

PURPOSE: The JAK1/2 inhibitor ruxolitinib has demonstrated significant benefits for patients with myeloproliferative neoplasms (MPN). However, patients often lose response to ruxolitinib or suffer disease progression despite therapy with ruxolitinib. These observations have prompted efforts to devise treatment strategies to improve therapeutic efficacy in combination with ruxolitinib therapy. Activation of JAK-STAT signaling results in dysregulation of key downstream pathways, notably increased expression of cell-cycle mediators including CDC25A and the PIM kinases. EXPERIMENTAL DESIGN: Given the involvement of cell-cycle mediators in MPNs, we sought to examine the efficacy of therapy combining ruxolitinib with a CDK4/6 inhibitor (LEE011) and a PIM kinase inhibitor (PIM447). We utilized JAK2-mutant cell lines, murine models, and primary MPN patient samples for these studies. RESULTS: Exposure of JAK2-mutant cell lines to the triple combination of ruxolitinib, LEE011, and PIM447 resulted in expected on-target pharmacodynamic effects, as well as increased apoptosis and a decrease in the proportion of cells in S-phase, compared with ruxolitinib. As compared with ruxolitinib monotherapy, combination therapy led to reductions in spleen and liver size, reduction of bone marrow reticulin fibrosis, improved overall survival, and elimination of disease-initiating capacity of treated bone marrow, in murine models of MPN. Finally, the triple combination reduced colony formation capacity of primary MPN patient samples to a greater extent than ruxolitinib. CONCLUSIONS: The triple combination of ruxolitinib, LEE011, and PIM447 represents a promising therapeutic strategy with the potential to increase therapeutic responses in patients with MPN.

Prevalence of polycythemia vera and essential thrombocythemia.

Polycythemia vera (PV) and essential thrombocythemia (ET) are common types of myeloproliferative disorders (MPD), the prevalence of which has not been well documented in the United States. Recent breakthroughs in the molecular etiology of these disorders and the accelerated development of targeted pharmacotherapeutics to treat them underscore the need to define the affected population. In this study, we obtained health claims data from major commercial insurance payers in Connecticut and the Center for Medicare and Medicaid Services to estimate the prevalence of PV and ET. Specifically, logistic regression was utilized to develop algorithms to predict the probability that an individual with claims suggestive of MPD truly has PV or ET, and the algorithms were then applied to health claims to estimate the number of PV and ET patients in Connecticut. As of 2003, the age-standardized prevalence was 22 per 100,000 and 24 per 100,000 for PV and ET, respectively, in Connecticut. Applying the age-specific prevalence of PV and ET to the entire US population resulted in an estimated total of 65,243 patients with PV and 71,078 patients with ET in the United States in 2003. This study is the first to assess the prevalence of PV and ET in a large US population. Given the large number of individuals afflicted with these diseases and the fact that demographic changes alone will further increase the burden of

Bcl-2 overexpression leads to increases in suppressor of cytokine signaling-3 expression in B cells and de novo follicular lymphoma.

The t(14;18)(q32;q21), resulting in deregulated expression of B-cell-leukemia/lymphoma-2 (Bcl-2), represents the genetic hallmark in human follicular lymphomas. Substantial evidence supports the hypothesis that the t(14;18) and Bcl-2 overexpression are necessary but not solely responsible for neoplastic transformation and require cooperating genetic derangements for neoplastic transformation to occur. To investigate genes that cooperate with Bcl-2 to influence cellular signaling pathways important for neoplastic transformation, we used oligonucleotide microarrays to determine differential gene expression patterns in CD19+ B cells isolated from Emu-Bcl-2 transgenic mice and wild-type littermate control mice. Fifty-seven genes were induced and 94 genes were repressed by > or =2-fold in Emu-Bcl-2 transgenic mice (P < 0.05). The suppressor of cytokine signaling-3 (SOCS3) gene was found to be overexpressed 5-fold in B cells from Emu-Bcl-2 transgenic mice. Overexpression of Bcl-2 in both mouse embryo fibroblast-1 and hematopoietic cell lines resulted in induction of SOCS3 protein, suggesting a Bcl-2-associated mechanism underlying SOCS3 induction. Immunohistochemistry with SOCS3 antisera on tissue from a cohort of patients with de novo follicular lymphoma revealed marked overexpression of SOCS3 protein that, within the follicular center cell region, was limited to neoplastic follicular lymphoma cells and colocalized with Bcl-2 expression in 9 of 12 de novo follicular lymphoma cases examined. In contrast, SOCS3 protein expression was not detected in the follicular center cell region of benign hyperplastic tonsil tissue. These data suggest that Bcl-2 overexpression leads to the induction of activated signal transducer and activator of transcription 3 (STAT3) and to the induction of SOCS3, which may contribute to the pathogenesis of follicular lymphoma.

The non-peptide thrombopoietin receptor agonist eltrombopag stimulates megakaryopoiesis in bone marrow cells from patients with relapsed multiple myeloma.

BACKGROUND: Thrombocytopenia is a significant problem in patients with relapsed or refractory multiple myeloma, precipitating a need for supportive platelet transfusions and necessitating decreases in delivered doses of chemotherapy. Eltrombopag is a non-peptide, small molecule thrombopoietin (TPO) receptor agonist that promotes megakaryopoiesis similar to endogenous human TPO and may be an effective agent for thrombocytopenia in this patient population. METHODS: We examined the effects of eltrombopag on megakaryocyte colony-forming capacity in CD34+ cells in patients with multiple myeloma and investigated its impact on proliferation, viability, and apoptosis in primary CD138+ human myeloma cells and myeloma cell lines. RESULTS: Eltrombopag at doses of 0.1 to 100 µM did not enhance proliferation of primary human CD138+ multiple myeloma cells from patients with relapsed disease or myeloma cell lines when used alone or in combination with erythropoietin (EPO) and granulocyte colony-stimulating factor (G-CSF) and did not alter cell viability nor apoptosis of human myeloma cells exposed to bortezomib and lenalidomide. Eltrombopag stimulated megakaryopoiesis in human CD34+ cells from normal individuals and from patients with relapsed multiple myeloma via activation of Akt signaling pathways. CONCLUSIONS: These results provide proof-of-principle supporting the design of future clinical studies examining eltrombopag for the treatment of thrombocytopenia in patients with advanced multiple myeloma.

Pim kinases modulate resistance to FLT3 tyrosine kinase inhibitors in FLT3-ITD acute myeloid leukemia.

Fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) is frequently detected in acute myeloid leukemia (AML) patients and is associated with a dismal long-term prognosis. FLT3 tyrosine kinase inhibitors provide short-term disease control, but relapse invariably occurs within months. Pim protein kinases are oncogenic FLT3-ITD targets expressed in AML cells. We show that increased Pim kinase expression is found in relapse samples from AML patients treated with FLT3 inhibitors. Ectopic Pim-2 expression induces resistance to FLT3 inhibition in both FLT3-ITD-induced myeloproliferative neoplasm and AML models in mice. Strikingly, we found that Pim kinases govern FLT3-ITD signaling and that their pharmacological or genetic inhibition restores cell sensitivity to FLT3 inhibitors. Finally, dual inhibition of FLT3 and Pim kinases eradicates FLT3-ITD(+) cells including primary AML cells. Concomitant Pim and FLT3 inhibition represents a promising new avenue for AML therapy.

Anemia in elderly patients: an emerging problem for the 21st century.

Anemia is a significant problem in elderly patients. Although many anemic elderly patients can be diagnosed with nutritional deficiency, anemia of chronic inflammation or comorbid diseases that explain their decreased hematocrit, the etiology of anemia in a significant fraction remains obscure. There is evidence to suggest that the hematopoietic stem cell displays increasing erythropoietin (EPO) resistance with age. EPO levels rise in elderly, nonanemic patients, and it is hypothesized that there is an interplay between this rising demand for EPO and the decreasing ability of the aging kidney to produce adequate hormone to meet that need. There is further considerable evidence that aging is associated with increased proinflammatory cytokine expression and that many of these cytokines can contribute to EPO insensitivity. Consequently, genetic variation in the expression of these proinflammatory cytokines may influence the development of anemia in elderly patients, both through induction of hepcidin expression (anemia of inflammation) and through cytokine suppression of erythroid colony formation. The impact of inflammatory mediators, EPO insensitivity, and other factors that may act on the hematopoietic stem cell to decrease erythropoiesis are under active study and should serve to elucidate the pathophysiology of this important cause of morbidity and mortality in elderly individuals. A better understanding of the pathophysiology of anemia in elderly patients should provide critical entry points for interventions that will improve survival and quality of life in the aging population.

Trends in prescribing beta-lactam antibiotics for treatment of community-associated methicillin-resistant Staphylococcus aureus infections.

Rates of prescribing of beta-lactam antibiotics as initial empirical therapy for patients with skin and soft tissue infections (SSTIs) caused by molecularly and epidemiologically characterized community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) isolates were assessed over a 3-year period. A prospectively developed database was used to calculate the prevalence of CA-MRSA SSTIs from 2004 to 2006. Molecular characterization of the MRSA isolate and medical record review for assessment of initial antimicrobial therapy were performed on a subset of patients. Among 2,636 patients with S. aureus SSTIs, the prevalence of CA-MRSA was 9% in 2004, 16% in 2005, and 21% in 2006 (P < 0.0001, chi-square test for trend). Seventy-five percent of CA-MRSA isolates tested were of the USA 300 or 400 clone type. Ninety-two percent of CA-MRSA isolates tested were positive for Panton-Valentine leukocidin, of which 90% carried staphylococcal chromosomal cassette mec type IV. The rate of use of a beta-lactam antibiotic as initial empirical therapy for patients with CA-MRSA SSTIs was 86%, 77%, and 60% in 2004, 2005, and 2006, respectively (P = 0.04, chi-square test for trend). Thirty percent of beta-lactam-treated patients had a documented risk factor for CA-MRSA infection. The use of a beta-lactam antibiotic as initial empirical therapy for CA-MRSA SSTIs has decreased significantly over the past 3 years. However, even as the prevalence of CA-MRSA SSTIs approaches 25%, the majority of patients are still receiving inactive antimicrobial therapy. Further evaluation of the outcomes associated with discordant therapy for CA-MRSA SSTIs is needed.

Overexpression of SOCS3 is associated with decreased survival in a cohort of patients with de novo follicular lymphoma.

The prognostic significance of SOCS3 protein expression was determined in de novo follicular lymphomas (FL) with t(14;18) and bcl-2 overexpression. Presentation lymph nodes from 82 FL patients for whom clinical information was available were immunohistochemically segregated into SOCS3-positive (n = 42) or -negative (n = 40) cohorts, and overall survival (OS) was analysed. SOCS3-positive FL patients had a median OS of 10 years compared with 22 years in SOCS3-negative patients (P = 0.001, log rank test). After adjusting for Follicular Lymphoma International Prognostic Index subgroups, SOCS3 overexpression remained an independent predictor of decreased OS (P < 0.001). These findings suggest that overexpression of SOCS3 may be an independent poor prognostic variable in patients with de novo FL.

The leukemia-associated gene Mllt1/ENL: characterization of a murine homolog and demonstration of an essential role in embryonic development.

MLLT1 (ENL/LTG19) is one of a number of fusion gene partners with the MLL oncogene involved in 11q23 translocations in human leukemia and encodes a transcriptional regulator of unknown function. Leukemias bearing MLL translocations may be myeloid or lymphoid or bear mixed lineage properties; however, those bearing MLL/MLLT1 translocations are predominantly lymphoid, suggesting that MLLT1 may influence the leukemic phenotype. The murine homolog Mllt1 exhibits 86% amino acid sequence identity with the human gene and is broadly expressed in murine tissues and cell lines, with the exception of liver and myeloid cell lines. We have mapped Mllt1 to mouse chromosome 17 band E2 using FISH analysis. The genomic structure and 5' regulatory sequence of Mllt1 are highly conserved between mouse and human. There is also conservation of the genomic structure, but not the promoter, between MLLT1 and MLLT3/AF9, a homologous gene that is also an MLL translocation partner in human leukemias with a predominant myeloid phenotype. Targeted disruption of Mllt1 in mice leads to embryonic lethality prior to 8.5 dpc. These studies indicate that MLLT1 is involved in essential developmental processes and suggest that expression patterns of MLL fusion partners may influence the lineage of MLL-associated leukemias.