Alphataxin, an Orally Available Small Molecule, Decreases LDL Levels in Mice as a Surrogate for the LDL-Lowering Activity of Alpha-1 Antitrypsin in Humans

The abundant blood protein α1-proteinase inhibitor (α1PI, Αlpha-1, α1-antitrypsin, SerpinA1) is known to bind to the active site of granule-associated human leukocyte elastase (HLE-G). Less well known is that binding of α1PI to cell surface HLE (HLE-CS) induces lymphocyte locomotion mediated by members of the low density lipoprotein receptor family (LDL-RFMs) thereby facilitating low density lipoprotein (LDL) clearance. LDL and α1PI were previously shown to be in negative feedback regulation during transport and clearance of lipoproteins. Further examination herein of the influence of α1PI in lipoprotein regulation using data from a small randomized, double-blind clinical trial shows that treatment of HIV-1-infected individuals with α1PI plasma products lowered apolipoprotein and lipoprotein levels including LDL. Although promising, plasma-purified α1PI is limited in quantity and not a feasible treatment for the vast number of people who need treatment for lowering LDL levels. We sought to develop orally available small molecules to act as surrogates for α1PI. Small molecule β-lactams are highly characterized for their binding to the active site of HLE-G including crystallographic studies at 1.84 Å. Using high throughput screening (HLE-G inhibition, HLE-CS-induced cellular locomotion), we show here that a panel of β-lactams, including the LDL-lowering drug ezetimibe, have the capacity to act as surrogates for α1PI by binding to HLE-G and HLE-CS. Because β-lactams are antibiotics that also have the capacity to promote evolution of antibiotic resistant bacteria, we modified the β-lactam Alphataxin to prevent antibiotic activity. We demonstrate using the diet-induced obesity (DIO) mouse model that Alphataxin, a penam, is as effective in lowering LDL levels as FDA-approved ezetimibe, a monobactam. Non-antibiotic β-lactams provide a promising new therapeutic class of small molecules for lowering LDL levels

α1Proteinase Inhibitor Regulates CD4+ Lymphocyte Levels and Is Rate Limiting in HIV-1 Disease

Background: The regulation of adult stem cell migration through human hematopoietic tissue involves the chemokine CXCL12 (SDF-1) and its receptor CXCR4 (CD184). In addition, human leukocyte elastase (HLE) plays a key role. When HLE is located on the cell surface (HLE CS), it acts not as a proteinase, but as a receptor for a 1proteinase inhibitor (a 1PI, a 1antitrypsin, SerpinA1). Binding of a1PI to HLECS forms a motogenic complex. We previously demonstrated that a1PI deficiency attends HIV-1 disease and that a1PI augmentation produces increased numbers of immunocompetent circulating CD4 + lymphocytes. Herein we investigated the mechanism underlying the a 1PI deficiency that attends HIV-1 infection. Methods and Findings: Active a 1PI in HIV-1 subjects (median 17 mM, n = 35) was significantly below normal (median 36 mM, p,0.001, n = 30). In HIV-1 uninfected subjects, CD4 + lymphocytes were correlated with the combined factors a1PI, HLECS + lymphocytes, and CXCR4 + lymphocytes (r 2 = 0.91, p,0.001, n = 30), but not CXCL12. In contrast, in HIV-1 subjects with.220 CD4 cells/ml, CD4 + lymphocytes were correlated solely with active a 1PI (r 2 =0.93,p,0.0001, n = 26). The monoclonal anti-HIV-1 gp120 antibody 3F5 present in HIV-1 patient blood is shown to bind and inactivate human a 1PI. Chimpanzee a 1PI differs from human a1PI by a single amino acid within the 3F5-binding epitope. Unlike human a1PI, chimpanzee a1PI did not bind 3F5 or become depleted following HIV-1 challenge, consistent with the normal CD4 + lymphocyte levels and benign syndrome of HIV-1 infected chimpanzees. The presence of IgG-a 1PI immune complexes correlated with decreased CD4 + lymphocytes in HIV-1 subjects

First-in-human technique translation of oxygen-enhanced MRI to an MR Linac system in patients with head and neck cancer

BACKGROUND AND PURPOSE: Tumour hypoxia is prognostic in head and neck cancer (HNC), associated with poor loco-regional control, poor survival and treatment resistance. The advent of hybrid MRI - radiotherapy linear accelerator or 'MR Linac' systems - could permit imaging for treatment adaptation based on hypoxic status. We sought to develop oxygen-enhanced MRI (OE-MRI) in HNC and translate the technique onto an MR Linac system. MATERIALS AND METHODS: MRI sequences were developed in phantoms and 15 healthy participants. Next, 14 HNC patients (with 21 primary or local nodal tumours) were evaluated. Baseline tissue longitudinal relaxation time (T1) was measured alongside the change in 1/T1 (termed ΔR1) between air and oxygen gas breathing phases. We compared results from 1.5 T diagnostic MR and MR Linac systems. RESULTS: Baseline T1 had excellent repeatability in phantoms, healthy participants and patients on both systems. Cohort nasal concha oxygen-induced ΔR1 significantly increased (p < 0.0001) in healthy participants demonstrating OE-MRI feasibility. ΔR1 repeatability coefficients (RC) were 0.023-0.040 s-1 across both MR systems. The tumour ΔR1 RC was 0.013 s-1 and the within-subject coefficient of variation (wCV) was 25% on the diagnostic MR. Tumour ΔR1 RC was 0.020 s-1 and wCV was 33% on the MR Linac. ΔR1 magnitude and time-course trends were similar on both systems. CONCLUSION: We demonstrate first-in-human translation of volumetric, dynamic OE-MRI onto an MR Linac system, yielding repeatable hypoxia biomarkers. Data were equivalent on the diagnostic MR and MR Linac systems. OE-MRI has potential to guide future clinical trials of biology guided adaptive radiotherapy

WNT activation by lithium abrogates TP53 mutation associated radiation resistance in medulloblastoma

TP53 mutations confer subgroup specific poor survival for children with medulloblastoma. We hypothesized that WNT activation which is associated with improved survival for such children abrogates TP53 related radioresistance and can be used to sensitize TP53 mutant tumors for radiation. We examined the subgroup-specific role of TP53 mutations in a cohort of 314 patients treated with radiation. TP53 wild-type or mutant human medulloblastoma cell-lines and normal neural stem cells were used to test radioresistance of TP53 mutations and the radiosensitizing effect of WNT activation on tumors and the developing brain. Children with WNT/TP53 mutant medulloblastoma had higher 5-year survival than those with SHH/TP53 mutant tumours (100% and 36.6% +/- 8.7%, respectively (p < 0.001)). Introduction of TP53 mutation into medulloblastoma cells induced radioresistance (survival fractions at 2Gy (SF2) of 89% +/- 2% vs. 57.4% +/- 1.8% (p < 0.01)). In contrast, beta-catenin mutation sensitized TP53 mutant cells to radiation (p < 0.05). Lithium, an activator of the WNT pathway, sensitized TP53 mutant medulloblastoma to radiation (SF2 of 43.5% +/- 1.5% in lithium treated cells vs. 56.6 +/- 3% (p < 0.01)) accompanied by increased number of.H2AX foci. Normal neural stem cells were protected from lithium induced radiation damage (SF2 of 33% +/- 8% for lithium treated cells vs. 27% +/- 3% for untreated controls (p = 0.05). Poor survival of patients with TP53 mutant medulloblastoma may be related to radiation resistance. Since constitutive activation of the WNT pathway by lithium sensitizes TP53 mutant medulloblastoma cells and protect normal neural stem cells from radiation, this oral drug may represent an attractive novel therapy for high-risk medulloblastomas.B.R.A.I.N Child Canada; Cancer Research UK; Brain Tumour Charity; Hungarian Brain Research Program [KTIA_13_NAP-A-V/3]; Janos Bolyai Scholarship of the Hungarian Academy of Sciences [TAMOP-4.2.2. A-11/1/KONV-2012-0025]; German Cancer Aid/Dr. Mildred Scheel Foundation for Cancer Research; Cure Childhood Cancer Foundation; St. Baldrick's Foundation; Southeastern Brain Tumor Foundation; Action Medical Research; [CZ.1.05/2.1.00/03.0101]; [CZ.1.07/2.3.00/20.0183

Comprehensive molecular characterization of gastric adenocarcinoma

Gastric cancer is a leading cause of cancer deaths, but analysis of its molecular and clinical characteristics has been complicated by histological and aetiological heterogeneity. Here we describe a comprehensive molecular evaluation of 295 primary gastric adenocarcinomas as part of The Cancer Genome Atlas (TCGA) project. We propose a molecular classification dividing gastric cancer into four subtypes: tumours positive for Epstein–Barr virus, which display recurrent PIK3CA mutations, extreme DNA hypermethylation, and amplification of JAK2, CD274 (also known as PD-L1) and PDCD1LG2 (also knownasPD-L2); microsatellite unstable tumours, which show elevated mutation rates, including mutations of genes encoding targetable oncogenic signalling proteins; genomically stable tumours, which are enriched for the diffuse histological variant and mutations of RHOA or fusions involving RHO-family GTPase-activating proteins; and tumours with chromosomal instability, which show marked aneuploidy and focal amplification of receptor tyrosine kinases. Identification of these subtypes provides a roadmap for patient stratification and trials of targeted therapies

Multiplatform Analysis of 12 Cancer Types Reveals Molecular Classification within and across Tissues of Origin

Recent genomic analyses of pathologically-defined tumor types identify “within-a-tissue” disease subtypes. However, the extent to which genomic signatures are shared across tissues is still unclear. We performed an integrative analysis using five genome-wide platforms and one proteomic platform on 3,527 specimens from 12 cancer types, revealing a unified classification into 11 major subtypes. Five subtypes were nearly identical to their tissue-of-origin counterparts, but several distinct cancer types were found to converge into common subtypes. Lung squamous, head & neck, and a subset of bladder cancers coalesced into one subtype typified by TP53 alterations, TP63 amplifications, and high expression of immune and proliferation pathway genes. Of note, bladder cancers split into three pan-cancer subtypes. The multi-platform classification, while correlated with tissue-of-origin, provides independent information for predicting clinical outcomes. All datasets are available for data-mining from a unified resource to support further biological discoveries and insights into novel therapeutic strategies

Corresponding conformation at the 3F5-recognized epitope in α₁PI and CD4-complexed HIV-1 gp120.

<p>HIV-1 gp120 is depicted from two perspectives (<b>A,B</b>) with green representing two α-helices (aa 100–115 and 476–484). The gp120 peptide immunogen used to raise 1C1 and 3F5 (aa 471–490) is located at the C-terminus of gp120, and the linear segment ⁴⁸⁶YKVV⁴⁸⁹ is depicted in red along with Met95 and the oligosaccharide-linked segment ²³⁴NGT²³⁶, all of which are within 8 Å of the conformational epitope. The gp120-homologous domain in α₁PI is also located at the C-terminus of the protein, and is depicted from two perspectives (<b>C,D</b>) with violet representing the antiparallel β-sheet strand at the base of the cleft (aa 369–389), and green representing the α-helices that form the mouth of the cleft (aa 27–44 and 259–277). Met-385, which distinguishes human from chimpanzee α₁PI, is depicted in red along with the segment ³⁸⁶GKVV³⁸⁹, the oligosaccharide, and oligosaccharide-linked segment ⁴⁶NST⁴⁸. The HLE_G-reactive site Met-358, is depicted in yellow for orientation. Structures for human α₁PI (1HP7) and CD4-complexed HIV-1 gp120 (1RZJ) from the NCBI Molecular Modeling Database (MMDB) were analyzed using Cn3D software. Small carbohydrate structures, depicted in multiple colors, were associated with 1RZJ in MMDB, and the three associated with 1HP7 were added using Adobe Photoshop.</p

Regression analysis of CD4⁺ and absolute lymphocyte numbers in HIV-1 uninfected subjects.

a<p>Values for independent and dependent variables represent mean ± standard deviation. HLE_CS⁺ lymphocytes and CXCR4⁺ lymphocytes in the lymphocyte gate (Ly) were quantitated using flow cytometry. Active α₁PI and CXCL12 were quantitated in serum as described.</p>b<p>Multilinear regression was performed to determine the relationship of the dependent variables to the independent variables using power of test α = 0.05. Dependent variables were considered to be significantly related to the independent variable if they contributed significantly to the multilinear regression (p<0.05). In this population sample, variables were found to have constant variance and normality.</p