Citations

Abstract Introduction: Clinical development of bortezomib in multiple myeloma (MM) included pharmacogenomic gene expression profiling (GEP) of pre-treatment tumor biopsies in order to evaluate the feasibility of developing predictive classifiers in prospective clinical trials and to better define the biological pathways related to drug sensitivity. By partitioning the samples into train (n=101) and test (n=80) datasets, statistically significant classifiers of response and survival were identified and then validated [Mulligan G, et al: Blood. 2007; 109:3177–88]. Here we describe specific genes and biological pathways associated with bortezomib efficacy in relapsed MM. Methods: Using tumor GEP data from 188 patients treated with single-agent bortezomib we identified genes associated with overall survival (OS), as well as genes associated with response (R) or progressive disease (PD) after bortezomib therapy. These clinical endpoints were also analyzed with biological pathway algorithms including GSEA [Subramanian A, et al: Proc Natl Acad Sci2005; 102:15545–50] Ingenuity Pathway Analysis and Gene Ontology/GATHER. These results were then compared to GEP data from a patient subset (n=76) treated with single-agent dexamethasone and also cell lines selected for differential sensitivity to bortezomib. Results: A comparison of R and PD highlighted numerous differentially expressed genes; approximately 200 were over-expressed in R and 500 were over-expressed in PD (t-test <0.01). R-associated genes include signaling molecules like TRADD, CFLAR and TANK, while PD-associated genes included oncogenes (NRAS), apoptotic regulators (DAP3) and cancer antigens (CTAG). Pathway tools helped to integrate and extend these observations, consistently identifying NFkB activation and overexpression of adhesion pathways as R-associated. Overexpression of protein synthesis and mitochondrial pathways were PD-associated. The overexpression of pathways such as NFkB, adhesion and cytokines appear linked specifically with bortezomib and not dexamethasone sensitivity. These approaches were also applied to patient survival. In contrast to analyses of single genes, the pathway tools highlighted links between response and survival, including adhesion and inflammatory cytokine pathway expression. Conclusions: This study highlights the diversity of biological pathways expressed in MM and the utility of clinical genomics to associate pathways with activity of single-agent bortezomib.

Abstract Background & Objectives: Diagnosis and classification of VWD are currently based on integration of personal and family bleeding histories and results of protein-based diagnostic tests (VWF:Ag, VWF:RCo, FVIII:C, VWF:CB and VWF multimers) which have performance limitations. Genetic testing is emerging as a complementary diagnostic tool. We have identified mutations and correlated VWF multimer patterns in our patients (pt) with types 2 & 3 VWD, and report novel candidate mutations. Patients & Methods: Unrelated pt with type 3 (n=6) and subtypes 2 (n=22) VWD, from Mayo Comprehensive Hemophilia Center, consented to this IRB approved study. PCR amplification, from genomic DNA, of VWF gene (splice junctions, coding and promoter regions), avoiding pseudogene amplification, followed by ABI® sequencing and analysis (Mutation Surveyor: SoftGenetic®) were performed. Mutations were compared to VWD (ISTH), NCBI NR nucleotide and DV SNP databases. Comparison with available VWF sequences from other vertebrate species was performed. Selected regions not known to contain mutations remain to be sequenced. VWF multimer analysis was performed using a novel in-gel immunostaining and infrared imaging system. Results: Type 2A VWD (n=10), a novel mutation in exon 28 (E28) (V1524G: 2 pt) with characteristic VWF multimer abnormalities (decreased HMWM, increased satellite banding, suggesting enhanced VWF proteolysis). Type 2B VWD (n=6), 2 pt were compound heterozygous for 2 previously reported mutations, the first in E28 (R1306W)/E48 (T2647M) and the second in E28 (V1316M)/E20 (R854Q). Type 2M VWD (n=4): an 84 yr female with personal (spontaneous and post-surgical) and family bleeding histories, VWF:RCo 72%, VWF:Ag 118% (RCo:Ag ratio 0.61), normal FVIII and platelets, and aberrant VWF multimer banding pattern without substantive reduction of HMWM, had a novel mutation in E52 (S2775C; conserved in mouse, rat, chicken and dog); a 14 yr female with a history of bleeding, VWF:RCo 34%, VWF:Ag 68% (RCo:Ag ratio 0.5) and normal FVIII and platelets, was compound heterozygous for a known mutation (R1399C subtype not classified in VWD database) and two novel mutations: E30 (P1725S) (conserved in mouse, rat, dog, cow and chimp) & E49 (T2666M) (conserved in mouse, dog, rat not in chicken). VWF multimers demonstrated abnormal banding pattern without substantive reduction of HMWM; 2 unrelated pt and families with ultra-large and smeary multimers, previously classified as Vicenza variant, had R1374C mutations and were reclassified as Type 2M VWD. Type 2N VWD (n=1) previously reported mutation E20 (R854Q) was confirmed. Type 3 VWD, 2 pt had novel mutations, the first in E22 (E950X) and the second was a compound heterozygote for E43 (R2478Q)/E40 (E2322V) mutations. In general, patients with similar mutations had similar multimer patterns. Conclusions: We report novel candidate mutations in types 2 & 3 VWD and demonstrate novel VWF multimer patterns with our in-gel staining system. Multimer patterns correlated well with the underlying genotype. The novel mutations are likely causative, given their occurrence at highly conserved residues, but this needs to be confirmed with expression studies. Integration of genetic testing into the diagnostic workup of VWD will potentially lead to more accurate diagnosis and subtyping of VWD, and may further refine protein based testing and provide additional biological insight into VWD.

Abstract HACS1 is a SH3 (Src homology 3) and SAM (sterile alpha motif) domain containing adaptor protein that is expressed in activated B and dendritic cells, is up-regulated by Interleukin 4 in the process of B cell activation and likely serves to dampen the immune response. To elucidate the function of HACS1, we generated HACS1 gene knockout mice by deletion of the SH3 and SAM domains. HACS1−/− mice were viable and fertile and had normal bone marrow B cell development and normal splenic T and B cell populations. However, adult HACS1−/− mice had increased numbers of peritoneal B1 cells (IgM+CD5+). Upon LPS plus BCR or TCR stimulations, splenic cells from HACS1−/− mice demonstrated an upregulation of activation markers with increased intensity of CD23 expression or increased population of CD69 positive cells. Purified B220+ splenic B cells from HACS1−/− mice showed increased cell proliferation upon BCR stimulation. Both T helper type 1 (Th1) and T helper type 2 (Th2) humoral responses were enhanced in HACS1−/− mice upon immunization with T cell-dependent antigen NP-KLH, which resulted in increased production of interferon-gamma (IFN-γ), anti-NP IgG2a and IL-4, as well as anti-NP IgG1 and IgE. Upon immunization with T cell-independent antigens such as TNP-LPS and TNP-Ficoll, HACS1−/− mice had increased production of anti-TNP IgM and IgG3 as compared to normal controls. The in vitro maturation of bone marrow-derived dentritic cells from HACS1−/− mice was similar to wild-type mice but HACS1−/− dentritic cells showed increased IL-12 production upon stimulation with anti-CD40 or LPS. There was no significant difference in antigen uptake by cultured dentritic cells from non-immunized wild-type or knockout mice. However, in immunized mice, an increase in antigen uptake in HACS1−/− dentritic cells was observed. We further demonstrate that the HACS1−/− B cells had increased tyrosine phosphorylation in the resting state. As deletion of the SH3 & SAM domains of HACS1 appears to generate a hypersensitive immune response, our results collectively support that HACS1 negatively regulates adaptive immunity.

Abstract Studies of the Syk −/− mouse have implicated spleen tyrosine kinase (Syk), a signaling protein with both kinase and scaffolding activities, in platelet signaling following engagement of GPVI and αIIbβ3 by collagen and fibrinogen, respectively. The present study was designed to determine whether specific inhibition of the kinase activity of Syk, without targeting the Syk scaffolding function, affected in vivo arterial thrombosis. In preliminary experiments, blood from wild-type and Syk−/− mice was perfused through collagen-coated capillaries under arterial shear rates to study ex vivo thrombosis. While blood from wild-type mice formed robust thrombi (37±4.7 μm3/μm2), none was observed in Syk−/− mice. Thrombi intermediate in size (16±3.9 μm3/μm2) developed in Syk+/− mice. To achieve specific pharmacological targeting of the kinase activity of Syk, P142-76, a potent (IC50 = 4 nM) and selective Syk kinase inhibitor was utilized. P142-76 was screened against a broad panel of 139 purified kinases at 50 nM. While Syk kinase was inhibited by 92%, all other kinases retained more than 70% of their activity. In washed human platelets, P142-76 inhibited convulxin (CVX)-induced phosphorylation of LAT (linker for activation of T-cells; IC50 = 111 nM) and intracellular calcium increases (IC50 = 31 nM). The GPVI/Syk-specificity of P142-76 activity was confirmed by its inability to inhibit intracellular calcium increases induced by the PAR1 thrombin receptor agonist TRAP. P142-76 also inhibited CVX-induced aggregation of both human washed platelets (IC50 = 87 nM) and platelet-rich plasma (IC50 = 2.5 μM). Considering the controversial data in respect to the participation of GPVI in arterial thrombosis in murine models, the dependence of arterial thrombosis on Syk function was studied in vivo in pigs. Cross-species activity of P142-76 was confirmed in vitro (CVX-induced PRP aggregation IC50= 350 nM; 5 μM P142-76 completely inhibited thrombosis triggered by collagen in the perfusion chamber assay). At a plasma concentration which abolished ex vivo CVX-induced but not ADP-induced pig platelet aggregation, P142-76 significantly inhibited the deposition of [111In]-labeled platelets in a carotid artery crush swine thrombosis model, without compromising primary hemostasis. % aggregation Swine (n=3) Platelet Deposition % inhibition Plasma Conc (ng/ml) Bleed Time (min) Activated Clotting Time (sec) ADP (20 μM) CVX (250 ng/ml) Control Artery 0 0 3±0.9 133±22 100 100 Treated Artery 76±6.5 1343±304 3.5±0.3 130±13 100 0 To clarify further the contribution of the kinase activity of Syk to arterial thrombosis, effects of P142-76 on human blood were evaluated in real time in the collagen-coated perfusion chamber. Low concentrations of P142-76 (0.3 μM) affected thrombus stability, while increasing concentrations (1–5 μM) delayed and then completely inhibited thrombus formation. Furthermore, P142-76 destabilized pre-formed thrombi, indicating a critical role for Syk in conferring strength to platelet-platelet interactions, i.e. αIIbβ3-mediated cohesion. Our data indicate that the kinase activity of Syk acts in arterial thrombosis through at least two distinct mechanisms. First, Syk kinase confers stability to platelet-platelet interactions downstream of αIIbβ3. Second, it initiates thrombus formation on collagen surfaces. This dual activity of the kinase activity of Syk makes it a preferred target for inhibition of arterial thrombosis, as it does not compromise primary hemostasis.

INTRODUCTION Patients with peripheral artery disease (PAD) are at a heightened risk of cardiovascular events and have markedly reduced vascular function and exercise tolerance. Heat therapy (HT) has emerged as a practical treatment to improve cardiovascular health in young individuals as well in patients with overt cardiovascular disease. We recently reported that a single 90 min session of HT applied to the legs of patients with PAD using water‐circulating trousers increases popliteal artery blood flow and reduces blood pressure and the circulating levels of the potent endogenous vasoconstrictor endothelin‐1 (ET‐1). The objective of the present study was to test the hypothesis that the repeated exposure to leg HT would lower blood pressure and ET‐1 levels and improve walking performance and conduit artery and cutaneous vascular function in patients with symptomatic PAD. METHODS Thirty‐two patients with symptomatic PAD (Age: 68± 8 years; Ankle‐brachial index: 0.67 ± 0.1) were assigned using a balanced randomized design to undergo 90 min of HT (48°C) or a thermoneutral treatment (33°C) 3 times per week for 6 consecutive weeks. The following outcomes were assessed at baseline and 3 and 6 weeks after the intervention: 1) resting ankle‐brachial index, 2) post‐occlusive reactive hyperemia in the popliteal artery (phase contrast magnetic resonance imaging), 3) leg cutaneous thermal hyperemia (laser Doppler flowmetry), 4) resting blood pressure every 5 min for 70 min, 5) 6‐min walk distance and 6) serum levels of ET‐1 and total nitrate (NOx). RESULTS Participants completed 17.7 ± 0.6 treatment sessions, resulting in a compliance rate of 98.7%. In the group exposed to HT, systolic blood pressure (SBP) decreased from baseline by ~3 mmHg at 6 weeks, while in the control group SBP increased by ~1 mmHg. A significant group by time interaction was observed for the changes in SBP from baseline to 6 weeks ( p=0.0049) with significant group differences at 20 min (Change in SBP: Control: 6.27 ± 15.5 vs. HT: −7.60 ± 13.6 mmHg, p=0.015 ) and 60 min (Change in SBP: Control: 4.13 ± 15.1 vs. HT: −7.33 ± 13.7 mmHg, p=0.0386 ). Similarly, serum ET‐1 levels decreased by ~15% from baseline to week 6 following exposure to HT, while a ~6% increase in this parameter occurred in the control group (Change in ET‐1: Control: 0.16 ± 0.6 vs. HT: −0.30 ± 0.4 pg/mL, p=0.035 – one outlier removed). Resting ABI, diastolic BP, 6MWT distance, hyperemic peak flow and cutaneous thermal hyperemia were not different between groups. CONCLUSION Exposure to repeated HT reduces systolic blood pressure and ET‐1 levels in patients with symptomatic PAD. These findings indicate that HT may be a practical and accessible nonpharmacological tool to reduce cardiovascular risk in PAD patients. Support or Funding Information American Heart Association Scientist Development grant (16SDG27600003).

Abstract Next‐generation sequencing identified about 60 genes recurrently mutated in chronic lymphocytic leukemia (CLL). We examined the additive prognostic value of the total number of recurrently mutated CLL genes (i.e., tumor mutational load [TML]) or the individually mutated genes beyond the CLL international prognostic index (CLL‐IPI) in newly diagnosed CLL and high‐count monoclonal B‐cell lymphocytosis (HC MBL). We sequenced 59 genes among 557 individuals (112 HC MBL/445 CLL) in a multi‐stage design, to estimate hazard ratios (HR) and 95% confidence intervals (CI) for time‐to‐first treatment (TTT), adjusted for CLL‐IPI and sex. TML was associated with shorter TTT in the discovery and validation cohorts, with a combined estimate of continuous HR = 1.27 (CI:1.17‐1.39, P = 2.6 × 10 −8 ; c ‐statistic = 0.76). When stratified by CLL‐IPI, the association of TML with TTT was stronger and validated within low/intermediate risk (combined HR = 1.54, CI:1.37‐1.72, P = 7.0 × 10 −14 ). Overall, 80% of low/intermediate CLL‐IPI cases with two or more mutated genes progressed to require therapy within 5 years, compared to 24% among those without mutations. TML was also associated with shorter TTT in the HC MBL cohort (HR = 1.53, CI:1.12‐2.07, P = .007; c ‐statistic = 0.71). TML is a strong prognostic factor for TTT independent of CLL‐IPI, especially among low/intermediate CLL‐IPI risk, and a better predictor than any single gene. Mutational screening at early stages may improve risk stratification and better predict TTT.

Insulin resistance is associated with skeletal muscle mitochondrial (mito) dysfunction in many conditions including type 2 diabetes (T2D). Poor glycemic control in T2D is associated with muscle mito gene transcript alterations. It is unknown whether muscle mito changes are related to reduced insulin action or vice versa. We obtained vastus lateralis muscle biopsies from 7 type 1 diabetic patients (T1D) following 8–12 hrs of insulin deprivation (I−) and replacement (I+) and measured skeletal muscle mito ATP production (MATP) and gene transcripts. I− and I+ changed glucose and glucagon levels (glucose=291±15mg/dl in I− vs 97±3 in I+ and glucagon=79.8±15.3 pg/mL in I− vs 47.3±5.9 in I+, p<0.04). Whole body O 2 consumption increased during I− by 15% (p<0.05) but maximal MATP decreased by 21.3–27.9% (p<0.05). Gene transcript profiling in skeletal muscle analyzed using Affymetrix GeneChip arrays showed alterations in 2355 transcripts. Pathway analysis showed down‐regulation of oxidative phosphorylation and arachidonic acid metabolism, and up‐regulation of VEGF and actin cytoskeleton signaling in I−. We conclude that the reduced insulin action that occurred during I− in T1D resulted in substantial changes in gene transcript levels of muscle mito genes and reduced maximal MATP, supporting that insulin is key regulator of muscle mito function by exerting its effect at various levels. Supported by NIHRO1DK41973.

7021 Background: Case-control studies (CCS) have identified germline variants (GVs) & genes associated with AML risk and/or outcome. However, whether these genes also harbor somatic mutations (SMs) in AML and whether these SMs are associated with clinical phenotypes and outcome is unknown. We systemically interrogated PubMed (terms "AML genetic polymorphisms"), yielding 612 reports (1981-2018), from which we identified unique variants/single nucleotide polymorphisms (SNPs) in 100 genes associated with AML risk and/or outcome in CCS. To determine the prevalence and relevance of SMs in these genes in an unselected AML population, we performed an analysis using WES of cases in the highly-annotated MCAEC (Finn, Ca Epidemiol 2015). Methods: We performed WES using remnant cytogenetic pellets from AML diagnosis in 98 MCAEC patients with available samples, sequenced at a depth of ~100 million paired-end 100bp reads using Agilent SureSelectXT Human All Exon V5 + UTRs target enrichment kit. Sequencing reads were aligned to human reference genome, and SMs including non-synonymous (NS) and truncating single nucleotide variants (SNVs) and small INDELs were identified and filtered using Exome Sequencing Project, 1000 genome, HapMap, & Mayo Clinic (MC) internal Biobank GV database. Copy number aberrations (CNAs) were identified & filtered using public CN polymorphism databases. For this analysis we evaluated the prevalence of somatic SNVs, INDELs, & CNAs in the 100 nominated genetic risk genes in collaboration with MC Cancer Center to determine their association with clinical phenotype and outcome. Results: Of the 100 unique genes, there were 40 with SM in our dataset, with 126 total mutations. Most were mutated in a very small number of patients, allowing insufficient statistical power to perform association analyses. However, an NS mutation in CYP2B6 (c.785A > G, p.Lys262Arg) had a minor allele frequency of 12.0%; this variant has been reported in association with breast cancer risk, but not with AML. Conclusions: We studied SM’s in AML genetic risk genes using WES of tumor samples. While representing a smaller sample size, this suggests their contribution to AML development may be limited in a broader clinical population. These results & prevalence of the novel CYP2B6 rs2279343 variant in AML must be confirmed in larger cohorts.

INTRODUCTION: Epigenetic modifications have been implicated to mediate several complications of diabetes mellitus (DM), especially nephropathy and retinopathy. Our aim was to ascertain whether epigenetic alterations in whole blood discriminate among patients with DM with normal, delayed, and rapid gastric emptying (GE). METHODS: Using the ChIP-seq (chromatin immunoprecipitation combined with next-generation sequencing) assays, we compared the genome-wide enrichment of 3 histone modifications (i.e., H3K4me3, H3K9ac, and H3K27ac) in buffy coats from 20 diabetic patients with gastrointestinal symptoms and normal (n = 6), delayed (n = 8), or rapid (n = 6) GE. RESULTS: Between patients with DM with delayed vs normal GE, there were 108 and 54 genes that were differentially bound (false discovery rate < 0.05) with H3K27ac and H3K9ac, respectively; 100 genes were differentially bound with H3K9ac in patients with rapid vs normal GE. The differentially bound genes with H3K27ac were functionally linked to the type 2 immune response, particularly Th2 cell activation and function (e.g., CCR3 , CRLF2 , CXCR4 , IL5RA , and IL1RL1 ) and glucose homeostasis ( FBP-1 , PDE4A , and CMKLR1 ). For H3K9ac, the differentially occupied genes were related to T-cell development and function (e.g., ICOS and CCR3 ) and innate immunity ( RELB , CD300LB , and CLEC2D ). Compared with normal GE, rapid GE had differential H3K9ac peaks at the promoter site of diverse immunity-related genes (e.g., TNFRSF25 and CXCR4 ) and genes related to insulin resistance and glucose metabolism. Motif analysis disclosed enrichment of binding sites for transcription factors relevant to the pathogenesis and complications of DM. DISCUSSION: GE disturbances in DM are associated with epigenetic alterations that pertain to dysimmunity, glucose metabolism, and other complications of DM.