Coexpression and functional cooperation of CTLA-4 and CD28 on activated T lymphocytes

T cell costimulation by molecules on the antigen presenting cell (APC) is required for optimal T cell proliferation. The B7 molecule on APC binds the T lymphocyte receptor CD28, triggering increased interleukin 2 (IL-2) production and subsequent T cell proliferation. CTLA-4 is a predicted T cell membrane receptor homologous to CD28, which also binds the B7 counter receptor, but whose distribution and function are unknown. Here we have developed monoclonal antibodies (mAbs) specific for CTLA-4 and have investigated these questions. mAbs were produced that bound CTLA-4 but not CD28, and that blocked binding of CTLA-4 to B7. CTLA-4 expression as measured by these mAbs was virtually undetectable on resting T cells, but was increased several hundred-fold during T cell activation. On activated lymphocytes, CTLA-4 was expressed equally on CD4+ and CD8+ T cell subsets and was coexpressed with CD25, CD28, and CD45RO. CTLA-4 expression was lower than that of CD28, reaching a maximum of approximately 1/30-50 the level of CD28. Despite its lower expression, CTLA-4 was responsible for much of the B7 binding by large activated T cells. Anti-CTLA-4 mAb 11D4 and anti-CD28 mAb 9.3 acted cooperatively to inhibit T cell adhesion to B7, and to block T cell proliferation in primary mixed lymphocyte culture. When coimmobilized with anti T cell receptor (TCR) mAb, anti-CTLA-4 mAbs were less effective than anti-CD28 mAb 9.3 at costimulating proliferation of resting or activated T cells. However, coimmobilized combinations of anti-CD28 and anti-CTLA-4 were synergistic in their ability to augment anti-TCR-induced proliferation of preactivated CD4+ T cells. These results indicate that CTLA-4 is coexpressed with CD28 on activated T lymphocytes and cooperatively regulates T cell adhesion and activation by B7.

Induction of alloantigen-specific hyporesponsiveness in human T lymphocytes by blocking interaction of CD28 with its natural ligand B7/BB1

The specificity of T lymphocyte activation is determined by engagement of the T cell receptor (TCR) by peptide/major histocompatibility complexes expressed on the antigen-presenting cell (APC). Lacking costimulation by accessory molecules on the APC, T cell proliferation does not occur and unresponsiveness to subsequent antigenic stimulus is induced. The B7/BB1 receptor on APCs binds CD28 and CTLA-4 on T cells, and provides a costimulus for T cell proliferation. Here, we show that prolonged, specific T cell hyporesponsiveness to antigenic restimulation is achieved by blocking the interaction between CD28 and B7/BB1 in human mixed leukocyte culture (MLC). Secondary T cell proliferative responses to specific alloantigen were inhibited by addition to the primary culture of monovalent Fab fragments of anti-CD28 monoclonal antibody (mAb) 9.3, which block interaction of CD28 with B7/BB1 without activating T cells. Hypo-responsiveness was also induced in MLC by CTLA4Ig, a chimeric immunoglobulin fusion protein incorporating the extracellular domain of CTLA-4 with high binding avidity for B7/BB1. Cells previously primed could also be made hyporesponsive, if exposed to alloantigen in the presence of CTLA4Ig. Maximal hyporesponsiveness was achieved in MLC after 2 d of incubation with CTLA4Ig, and was maintained for at least 27 d after removal of CTLA4Ig. Accumulation of interleukin 2 (IL-2) and interferon gamma but not IL-4 mRNA was blocked by CTLA4Ig in T cells stimulated by alloantigen. Antigen-specific responses could be restored by addition of exogenous IL-2 at the time of the secondary stimulation. Addition to primary cultures of the intact bivalent anti-CD28 mAb 9.3, or B7/BB1+ transfected CHO cells or exogenous IL-2, abrogated induction of hyporesponsiveness by CTLA4Ig. These data indicate that interaction of CD28 with B7/BB1 during TCR engagement with antigen is required to maintain T cell competence and that blocking such interaction can result in a state of T cell hyporesponsiveness.

Complications of cholecystectomy: risks of the laparoscopic approach and protective effects of operative cholangiography: a population-based study

BACKGROUND

Previous studies suggest that laparoscopic cholecystectomy (LC) is associated with an increased risk of intraoperative injury involving the bile ducts, bowel, and vascular structures compared with open cholecystectomy (OC). Population-based studies are required to estimate the magnitude of the increased risk, to determine whether this is changing over time, and to identify ways by which this might be reduced.

METHODS

Suspected cases of intraoperative injury associated with cholecystectomy in Western Australia in the period 1988 to 1994 were identified from routinely collected hospital statistical records and lists of persons undergoing postoperative endoscopic retrograde cholangiopancreatography. The case records of suspect cases were reviewed to confirm the nature and site of injury. Ordinal logistic regression was used to estimate the risk of injury associated with LC compared with OC after adjusting for confounding factors.

RESULTS

After the introduction of LC in 1991, the proportion of all cholecystectomy cases with intraoperative injury increased from 0.67% in 1988-90 to 1.33% in 1993-94. Similar relative increases were observed in bile duct injuries, major bile leaks, and other injuries to bowel or vascular structures. Increases in intraoperative injury were observed in both LC and OC. After adjustment for age, gender, hospital type, severity of disease, intraoperative cholangiography, and calendar period, the odds ratio for intraoperative injury in LC compared with OC was 1.79. Operative cholangiography significantly reduced the risk of injury.

CONCLUSION

Operative cholangiography has a protective effect for complications of cholecystectomy. Compared with OC, LC carries a nearly twofold higher risk of major bile, vascular, and bowel complications. Further study is required to determine the extent to which potentially preventable factors contribute to this risk.

"Fluorescent timer": protein that changes color with time

We generated a mutant of the red fluorescent protein drFP583. The mutant (E5) changes its fluorescence from green to red over time. The rate of color conversion is independent of protein concentration and therefore can be used to trace time-dependent expression. We used in vivo labeling with E5 to measure expression from the heat shock-dependent promoter in Caenorhabditis elegans and from the Otx-2 promoter in developing Xenopus embryos. Thus, E5 is a "fluorescent timer" that can be used to monitor both activation and down-regulation of target promoters on the whole-organism scale.

Recruitment of a ROC1-CUL1 ubiquitin ligase by Skp1 and HOS to catalyze the ubiquitination of I kappa B alpha

Activation of the transcription factor NF-kappa B in response to proinflammatory stimuli requires the phosphorylation-triggered and ubiquitin-dependent degradation of the NF-kappa B inhibitor, I kappa B alpha. Here, we show the in vitro reconstitution of the phosphorylation-dependent ubiquitination of I kappa B alpha with purified components. ROC1, a novel SCF-associated protein, is recruited by cullin 1 to form a quatemary SCFHOS-ROC1 holenzyme (with Skp1 and the beta-TRCP homolog HOS). SCFHOS-ROC1 binds IKK beta-phosphorylated I kappa B alpha and catalyzes its ubiquitination in the presence of ubiquitin, E1, and Cdc34. ROC1 plays a unique role in the ubiquitination reaction by heterodimerizing with cullin 1 to catalyze ubiquitin polymerization.

Molecular classification of gastric cancer

Gastric cancer (GC), a heterogeneous disease characterized by epidemiologic and histopathologic differences across countries, is a leading cause of cancer-related death. Treatment of GC patients is currently suboptimal due to patients being commonly treated in a uniform fashion irrespective of disease subtype. With the advent of next-generation sequencing and other genomic technologies, GCs are now being investigated in great detail at the molecular level. High-throughput technologies now allow a comprehensive study of genomic and epigenomic alterations associated with GC. Gene mutations, chromosomal aberrations, differential gene expression and epigenetic alterations are some of the genetic/epigenetic influences on GC pathogenesis. In addition, integrative analyses of molecular profiling data have led to the identification of key dysregulated pathways and importantly, the establishment of GC molecular classifiers. Recently, The Cancer Genome Atlas (TCGA) network proposed a four subtype classification scheme for GC based on the underlying tumor molecular biology of each subtype. This landmark study, together with other studies, has expanded our understanding on the characteristics of GC at the molecular level. Such knowledge may improve the medical management of GC in the future.

The shear mode of multilayer graphene

The quest for materials capable of realizing the next generation of electronic and photonic devices continues to fuel research on the electronic, optical and vibrational properties of graphene. Few-layer graphene (FLG) flakes with less than ten layers each show a distinctive band structure. Thus, there is an increasing interest in the physics and applications of FLGs. Raman spectroscopy is one of the most useful and versatile tools to probe graphene samples. Here, we uncover the interlayer shear mode of FLGs, ranging from bilayer graphene (BLG) to bulk graphite, and suggest that the corresponding Raman peak measures the interlayer coupling. This peak scales from ~43 cm(-1) in bulk graphite to ~31 cm(-1) in BLG. Its low energy makes it sensitive to near-Dirac point quasiparticles. Similar shear modes are expected in all layered materials, providing a direct probe of interlayer interactions.

What influences medical students' choice of surgical careers

BACKGROUND

Recent emphasis in medical education has been to encourage students to pursue primary care careers. This could have a negative impact on applications to surgical residencies.

METHODS

To determine what factors are most influential for a student to pursue a surgical career in spite of this environment, third- and fourth-year medical students were surveyed with a 40-item questionnaire.

RESULTS

The response rate was 37% (76/205). Those students considering a career in surgery were more likely than their counterparts to be motivated by role models (P <.006), career opportunities (P <.006), and academic opportunities (P <.013) in surgery. They were less likely than their counterparts to be discouraged from surgery on the basis of lifestyle (P <.001), time commitment (P <.001), call schedules (P <.001), or residency length (P <.028). No differences regarding financial rewards, research opportunities, or intellectual challenges were seen between the groups. Neither race nor sex had a significant role in the selection of surgery as a career.

CONCLUSIONS

The data suggests that students are more likely to be influenced to pursue surgical careers by offering early exposure to positive role models and career and academic opportunities in surgery. Knowledge of these influences on student career choices should help surgical educators attract and maintain student interest in surgical careers.

Meta-analysis of microsatellite instability in relation to clinicopathological characteristics and overall survival in gastric cancer

BACKGROUND

Several associations between microsatellite instability (MSI) and other clinicopathological factors have been reported in gastric cancer, but the results have been ambiguous. This systematic review and meta-analysis investigated the relationship between MSI and overall survival and clinicopathological characteristics of patients with gastric cancer.

METHODS

A systematic literature search of the PubMed, Cochrane and Ovid databases until 31 January 2016 was performed in accordance with the PRISMA statement. The articles were screened independently according to PICO (population, intervention, comparator, outcome) eligibility criteria. All eligible articles were evaluated independently by two reviewers for risk of bias according to the Quality In Prognosis Study tool.

RESULTS

Overall, 48 studies with a total of 18 612 patients were included. MSI was found in 9·2 per cent of patients (1718 of 18 612), and was associated with female sex (odds ratio (OR) 1·57, 95 per cent c.i. 1·31 to 1·89; P < 0·001), older age (OR 1·58, 2·20 to 1·13; P < 0·001), intestinal Laurén histological type (OR 2·23, 1·94 to 2·57; P < 0·001), mid/lower gastric location (OR 0·38, 0·32 to 0·44; P < 0·001), lack of lymph node metastases (OR 0·70, 0·57 to 0·86, P < 0·001) and TNM stage I-II (OR 1·77, 1·47 to 2·13; P < 0·001). The pooled hazard ratio for overall survival of patients with MSI versus those with non-MSI gastric cancer from 21 studies was 0·69 (95 per cent c.i. 0·56 to 0·86; P < 0·001).

CONCLUSION

MSI in gastric cancer was associated with good overall survival, reflected in several favourable clinicopathological tumour characteristics.

Prospective evaluation of patients refused admission to an intensive care unit: triage, futility and outcome

OBJECTIVES

To evaluate factors associated with decisions to refuse ICU admission and to assess the outcome of refused patients.

DESIGN AND SETTING

Prospective, descriptive evaluation in a multi-disciplinary intensive care unit, university referral hospital.

PATIENTS AND PARTICIPANTS

All adult emergency referrals over a 7-month period.

INTERVENTIONS

The number of beds available at the time of referral, the patient's age, gender, diagnosis, mortality probability model score and hospital survival were documented. The outcome of the referral and the reason for refusal were recorded.

MEASUREMENTS AND RESULTS

Of 624 patients 388 were admitted and 236 (38%) refused. Reasons for refusal were triage (n=104), futility (n=82) and inappropriate referral (too well; n=50). The standardised mortality ratio (SMR) for refused and admitted groups was 1.24 (95% CI 1.05-1.46) and 0.93 (0.78-1.09) respectively. The SMR ratio (refused SMR/admitted SMR) was highest in the middle range of illness (1.95, 1.19-3.20). Inappropriate referrals had a better than expected outcome despite refusal, with a SMR ratio of 0.39 (0.11-0.99). Excluding inappropriate referrals, multivariate analysis demonstrated that refusal was associated with older age, diagnostic group and severity of illness. Triage decisions were associated with a diagnosis of sepsis, and futility decisions with greater severity of illness and recent cardiac arrest.

CONCLUSIONS

Refusal of admission to our ICU is common. Excess mortality of patients refused is most marked in the middle range of severity of illness. Age, diagnostic group, and severity of illness are important in decision making. Strategies should be developed to create admission criteria that would identify patients in the middle range of severity of illness who should benefit most from ICU care.

Site-directed mutagenesis studies of the high-affinity streptavidin-biotin complex: contributions of tryptophan residues 79, 108, and 120

We report the functional characterization of site-directed biotin binding-site mutants of recombinant core streptavidin. The mutagenesis studies were aimed at characterizing the contributions of Trp residues known to contact biotin that have been postulated to control the exceptional binding affinity observed in this system. The functional properties of single site-directed mutants replacing Trp residues with Phe or Ala at positions 79, 108, and 120 were investigated by quantitating the EC50 binding parameters of these mutants to biotin and 2-iminobiotin in an ELISA format. The biotin EC50 for all mutants was the same as wild-type streptavidin, demonstrating that their delta Ka values relative to wild type were < 10(6). The conservative W79F and W108F mutants displayed only a 2- to 3-fold increase in EC50 for 2-iminobiotin, corresponding to an estimated delta Ka < 10, while the W120F mutant displayed a much greater alteration in 2-iminobiotin EC50, corresponding to an estimated delta Ka of 10(2). These delta Ka values are likely to reflect similar changes for biotin. The 2-iminobiotin EC50 values for the Ala mutants fell outside the accessible concentration range of the ELISA assay, demonstrating that these mutations lowered the Ka by a factor of 10(4) to 10(6). Direct estimation of biotin Ka values for W79A, W120A, and W120F in an ultrafiltration binding assay yielded Ka values of 4.3 x 10(7) M-1, 8.6 x 10(6) M-1, and > 5 x 10(9) M-1, respectively, in excellent agreement with the ELISA estimates of delta Ka with 2-iminobiotin as a reporter ligand. The results of these preliminary functional studies suggest that these aromatic side chains contribute significantly to the streptavidin-biotin binding free energy.

Carrier and polarization dynamics in monolayer MoS2

In monolayer MoS2, optical transitions across the direct band gap are governed by chiral selection rules, allowing optical valley initialization. In time-resolved photoluminescence (PL) experiments, we find that both the polarization and emission dynamics do not change from 4 to 300 K within our time resolution. We measure a high polarization and show that under pulsed excitation the emission polarization significantly decreases with increasing laser power. We find a fast exciton emission decay time on the order of 4 ps. The absence of a clear PL polarization decay within our time resolution suggests that the initially injected polarization dominates the steady-state PL polarization. The observed decrease of the initial polarization with increasing pump photon energy hints at a possible ultrafast intervalley relaxation beyond the experimental ps time resolution. By compensating the temperature-induced change in band gap energy with the excitation laser energy, an emission polarization of 40% is recovered at 300 K, close to the maximum emission polarization for this sample at 4 K.

Impaired immune responses and altered peptide repertoire in tapasin-deficient mice

Tapasin is a component of the major histocompatibility complex (MHC) class I antigen-loading complex. Here we show that mice with a disrupted tapasin gene display reduced MHC class I expression. Cytotoxic T cell (CTL) responses to viruses are impaired, and dendritic cells of tapasin-deficient mice do not cross-present protein antigen via the MHC class I pathway, indicating a defect in antigen processing. Natural killer (NK) cells from tapasin-deficient mice have an altered repertoire and are self-tolerant. In addition, the repertoire of class I-bound peptides is altered towards less stably binding ones. Thus tapasin plays a role in CTL and NK immune responses and in optimal peptide selection.

Metaplastic carcinoma of the breast: a clinicopathological review

BACKGROUND

Mammary metaplastic carcinoma encompasses epithelial-only carcinoma (high-grade adenosquamous carcinoma or pure squamous cell carcinoma), biphasic epithelial and sarcomatoid carcinoma and monophasic spindle cell carcinoma.

AIM

To evaluate the clinicopathological features of a large series of 34 metaplastic carcinomas.

METHODS

10 epithelial-only, 14 biphasic and 10 monophasic metaplastic carcinomas were assessed for nuclear grade, hormone receptor status, HER2/neu (cerbB2) oncogene expression, Ki-67 and p53, lymph node status and recurrence on follow-up.

RESULTS

Intermediate to high nuclear grade were assessed in most (33/34) tumours. Oestrogen and progesterone receptors were negative in 8 of 10 epithelial-only, all 14 biphasic, and 9 of 10 monophasic tumours, cerbB2 was negative in 7 of 10 epithelial-only, all 14 biphasic and 8 of 10 monophasic tumours. Ki-67 was found to be positive in 6 of 10 epithelial-only, 6 of 14 biphasic, and 7 of 10 monophasic tumours, whereas p53 was positive in 6 of 10 epithelial-only, 7 of 14 biphasic, and 8 of 10 monophasic tumours. Lymph node metastases were seen in 7 of 7 epithelial-only, 7 of 11 biphasic, and 3 of 7 monophasic tumours. Recurrences were seen in 4 of 7 epithelial-only, 8 of 9 biphasic, and 4 of 9 monophasic tumours.

CONCLUSIONS

All three subtypes of metaplastic carcinoma are known to behave aggressively, and should be differentiated from the low-grade fibromatosis-like metaplastic carcinoma, which does not metastasize. Oncological treatment options may be limited by the frequently negative status of hormonal receptor and cerbB2.

Identification of amino acid residues critical for aggregation of human CC chemokines macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and RANTES. Characterization of active disaggregated chemokine variants

Human CC chemokines macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and RANTES (regulated on activation normal T cell expressed) self-associate to form high-molecular mass aggregates. To explore the biological significance of chemokine aggregation, nonaggregating variants were sought. The phenotypes of 105 hMIP-1alpha variants generated by systematic mutagenesis and expression in yeast were determined. hMIP-1alpha residues Asp26 and Glu66 were critical to the self-association process. Substitution at either residue resulted in the formation of essentially homogenous tetramers at 0.5 mg/ml. Substitution of identical or analogous residues in homologous positions in both hMIP-1beta and RANTES demonstrated that they were also critical to aggregation. Our analysis suggests that a single charged residue at either position 26 or 66 is insufficient to support extensive aggregation and that two charged residues must be present. Solution of the three-dimensional NMR structure of hMIP-1alpha has enabled comparison of these residues in hMIP-1beta and RANTES. Aggregated and disaggregated forms of hMIP-1alpha, hMIP-1beta, and RANTES generally have equivalent G-protein-coupled receptor-mediated biological potencies. We have therefore generated novel reagents to evaluate the role of hMIP-1alpha, hMIP-1beta, and RANTES aggregation in vitro and in vivo. The disaggregated chemokines retained their human immunodeficiency virus (HIV) inhibitory activities. Surprisingly, high concentrations of RANTES, but not disaggregated RANTES variants, enhanced infection of cells by both M- and T-tropic HIV isolates/strains. This observation has important implications for potential therapeutic uses of chemokines implying that disaggregated forms may be necessary for safe clinical investigation.

Event generator tunes obtained from underlying event and multiparton scattering measurements

New sets of parameters ("tunes") for the underlying-event (UE) modelling of the pythia8, pythia6 and herwig++ Monte Carlo event generators are constructed using different parton distribution functions. Combined fits to CMS UE proton-proton ([Formula: see text]) data at [Formula: see text] and to UE proton-antiproton ([Formula: see text]) data from the CDF experiment at lower [Formula: see text], are used to study the UE models and constrain their parameters, providing thereby improved predictions for proton-proton collisions at 13[Formula: see text]. In addition, it is investigated whether the values of the parameters obtained from fits to UE observables are consistent with the values determined from fitting observables sensitive to double-parton scattering processes. Finally, comparisons are presented of the UE tunes to "minimum bias" (MB) events, multijet, and Drell-Yan ([Formula: see text] lepton-antilepton+jets) observables at 7 and 8[Formula: see text], as well as predictions for MB and UE observables at 13[Formula: see text].

Endorectal magnetic resonance imaging and spectroscopy for the detection of tumor foci in men with prior negative transrectal ultrasound prostate biopsy

PURPOSE

We determined the ability of combined endorectal magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) to detect prostate cancer foci prospectively in men with prior negative transrectal ultrasound (TRUS) prostate biopsy.

MATERIALS AND METHODS

Endorectal MRI with spectroscopy was performed in 24 consecutive patients with 1 or more prior negative TRUS prostatic biopsies for persistently increased prostate specific antigen and/or abnormal digital rectal examination. All studies were interpreted by a dedicated radiologist who reported areas of interest in the peripheral zone as normal, equivocal or suspicious on MRI and MRSI separately. Equivocal and suspicious areas were then correlated with a 3-dimensional prostate model. All patients underwent a standard TRUS 10-core peripheral zone biopsy with up to 4 additional biopsies targeted at the equivocal or suspected sites.

RESULTS

Prostate cancer was detected in 7 of 24 subjects (29.2%). Considering the equivocal category as test negative the sensitivity, specificity, positive and negative predictive values, and the accuracy of MRI, MRSI and combined MRI/MRSI for the detection of prostate cancer were 57.1%, 57.1% and 100.0%, 88.2%, 82.4% and 70.6%, 66.7%, 57.1% and 58.3%, 83.3%, 82.1% and 100%, and 79.2%, 75.0% and 79.2%, respectively. The site of positive biopsy correlated correctly in 50% and 28.6% of MRI and MRSI labeled suspicious cores, respectively.

CONCLUSIONS

MRI and MRSI have the potential to identify cancer foci and direct TRUS in patients with a previous negative TRUS biopsy. Further, larger studies are required to quantify the amount of benefit.

JAK-STAT and G-protein-coupled receptor signaling pathways are frequently altered in epitheliotropic intestinal T-cell lymphoma

Epitheliotropic intestinal T-cell lymphoma (EITL, also known as type II enteropathy-associated T-cell lymphoma) is an aggressive intestinal disease with poor prognosis and its molecular alterations have not been comprehensively characterized. We aimed to identify actionable easy-to-screen alterations that would allow better diagnostics and/or treatment of this deadly disease. By performing whole-exome sequencing of four EITL tumor-normal pairs, followed by amplicon deep sequencing of 42 tumor samples, frequent alterations of the JAK-STAT and G-protein-coupled receptor (GPCR) signaling pathways were discovered in a large portion of samples. Specifically, STAT5B was mutated in a remarkable 63% of cases, JAK3 in 35% and GNAI2 in 24%, with the majority occurring at known activating hotspots in key functional domains. Moreover, STAT5B locus carried copy-neutral loss of heterozygosity resulting in the duplication of the mutant copy, suggesting the importance of mutant STAT5B dosage for the development of EITL. Dysregulation of the JAK-STAT and GPCR pathways was also supported by gene expression profiling and further verified in patient tumor samples. In vitro overexpression of GNAI2 mutants led to the upregulation of pERK1/2, a member of MEK-ERK pathway. Notably, inhibitors of both JAK-STAT and MEK-ERK pathways effectively reduced viability of patient-derived primary EITL cells, indicating potential therapeutic strategies for this neoplasm with no effective treatment currently available.

Quantum circuits with many photons on a programmable nanophotonic chip

Growing interest in quantum computing for practical applications has led to a surge in the availability of programmable machines for executing quantum algorithms1,2. Present-day photonic quantum computers3-7 have been limited either to non-deterministic operation, low photon numbers and rates, or fixed random gate sequences. Here we introduce a full-stack hardware-software system for executing many-photon quantum circuit operations using integrated nanophotonics: a programmable chip, operating at room temperature and interfaced with a fully automated control system. The system enables remote users to execute quantum algorithms that require up to eight modes of strongly squeezed vacuum initialized as two-mode squeezed states in single temporal modes, a fully general and programmable four-mode interferometer, and photon number-resolving readout on all outputs. Detection of multi-photon events with photon numbers and rates exceeding any previous programmable quantum optical demonstration is made possible by strong squeezing and high sampling rates. We verify the non-classicality of the device output, and use the platform to carry out proof-of-principle demonstrations of three quantum algorithms: Gaussian boson sampling, molecular vibronic spectra and graph similarity8. These demonstrations validate the platform as a launchpad for scaling photonic technologies for quantum information processing.

IC261 induces cell cycle arrest and apoptosis of human cancer cells via CK1δ/ɛ and Wnt/β-catenin independent inhibition of mitotic spindle formation

Casein kinase 1 delta and epsilon (CK1δ/ɛ) are key regulators of diverse cellular growth and survival processes including Wnt signaling, DNA repair and circadian rhythms. Recent studies suggest that they have an important role in oncogenesis. RNA interference screens identified CK1ɛ as a pro-survival factor in cancer cells in vitro and the CK1δ/ɛ-specific inhibitor IC261 is remarkably effective at selective, synthetic lethal killing of cancer cells. The recent development of the nanomolar CK1δ/ɛ-selective inhibitor, PF670462 (PF670) and the CK1ɛ-selective inhibitor PF4800567 (PF480) offers an opportunity to further test the role of CK1δ/ɛ in cancer. Unexpectedly, and unlike IC261, PF670 and PF480 were unable to induce cancer cell death. PF670 is a potent inhibitor of CK1δ/ɛ in cells; nanomolar concentrations are sufficient to inhibit CK1δ/ɛ activity as measured by repression of intramolecular autophosphorylation, phosphorylation of disheveled2 proteins and Wnt/β-catenin signaling. Likewise, small interfering RNA knockdown of CK1δ and CK1ɛ reduced Wnt/β-catenin signaling without affecting cell viability, further suggesting that CK1δ/ɛ inhibition may not be relevant to the IC261-induced cell death. Thus, while PF670 is a potent inhibitor of Wnt signaling, it only modestly inhibits cell proliferation. In contrast, while sub-micromolar concentrations of IC261 neither inhibited CK1δ/ɛ kinase activity nor blocked Wnt/β-catenin signaling in cancer cells, it caused a rapid induction of prometaphase arrest and subsequent apoptosis in multiple cancer cell lines. In a stepwise transformation model, IC261-induced killing required both overactive Ras and inactive p53. IC261 binds to tubulin with an affinity similar to colchicine and is a potent inhibitor of microtubule polymerization. This activity accounts for many of the diverse biological effects of IC261 and, most importantly, for its selective cancer cell killing.

Antibody targeted gene transfer to endothelium

BACKGROUND

One of the drawbacks of the currently available vectors for gene therapy is the lack of selectivity in gene delivery. We have therefore investigated a strategy to generate immunoliposomes to target non-viral vectors to cell surface receptors on endothelium.

MATERIALS AND METHODS

We have developed a novel method of coupling antibodies (Abs) to liposomes complexed to DNA, using mild heat treatment to aggregate the immunoglobulin G (IgG). The interaction of plasmid DNA, liposomes and Abs was measured using a gel retardation assay and a resonant mirror biosensor. The size of the transfection complex was determined by light scattering, and the binding and internalization of the complex to cells was followed using flow cytometry. The transfection ability was tested on cell lines and primary cells in vitro and human corneal or vascular tissues ex vivo.

RESULTS

The interaction of antibodies with liposomes is relatively stable (t(1/2) congruent with 45 min). The size of the liposome, Ab and DNA complex was found to be around 500 nm in 4% BSA. The addition of anti-transferrin receptor Abs increased the internalization of the liposome-DNA complex into cells. Abs against both transferrin receptor and E-selectin were shown to augment transfection efficiency of liposomes to cell expressing the appropriate antigens. They are also shown to be efficient in mediating gene delivery to corneal and vascular tissues ex vivo.

CONCLUSIONS

We have shown that our novel vector is capable of in vitro and ex vivo gene delivery to cells and human tissues including cornea, artery and vein. In particular, an Ab against E-selectin was effective at selectively delivering genes to activated endothelial cells expressing the adhesion molecule. Such a strategy will have applications for targeting these tissues prior to transplantation or autologous grafting, and, in the longer term, may allow in vivo targeting of gene therapy to inflammatory sites.

Clinical porcine islet xenotransplantation under comprehensive regulation

BACKGROUND

Xenotransplantation with porcine islets is a promising approach to overcome the shortage of human donors. This is the first report of phase 1/2a xenotransplantation study of encapsulated neonatal porcine islets under the current framework of regulations for xenotransplantation in New Zealand.

METHODS

Newborn piglets were anesthetized and bled, and the pancreata were removed with the use of sterile technique and processed. Encapsulated neonatal porcine islets were implanted with the use of laparoscopy into the peritoneal cavity of 14 patients with unstable type 1 diabetes without any immunosuppressive drugs. The patients received encapsulated islets of 5,000 (n = 4; group 1), 10,000 (n = 4; group 2), 15,000 (n = 4; group 3), or 20,000 (n = 2; group 4) islet equivalents per kg body weight. Outcome was determined from adverse event reports, HbA1c, total daily insulin dose, and frequency of unaware hypoglycemic events. To assess graft function, transplant estimated function (TEF) scores were calculated. Sufficient or marginal numbers of encapsulated neonatal porcine islets were transplanted into streptozotocin-induced diabetic B6 mice as an in vivo functional assay.

RESULTS

There were 4 serious adverse events, of which 3 were considered to be possibly related to the procedure. Tests for porcine endogenous retrovirus DNA and RNA were all negative. The numbers of unaware hypoglycemia events were reduced after transplantation in all groups. Four of 14 patients attained HbA1c <7% compared with 1 at baseline. The average TEF scores were 0.17, 0.02, -0.01, and 0.08 in groups 1, 2, 3, and 4 respectively. The in vivo study demonstrated that a sufficient number of the transplanted group reversed diabetes with positive porcine C-peptide.

CONCLUSIONS

Transplantation of encapsulated neonatal porcine islets was safe and was followed by a reduction in unaware hypoglycemia events in unstable type 1 diabetic patients. The mouse in vivo assessment data demonstrated certain graft function.

Biocompatibility of electroactive polymers in tissues

The biocompatibility of ethylene-vinyl acetate copolymer (EVAc), polyethylene (PE), and polyaniline (PANi) films in the emeraldine (EM), nigraniline (NA) and leucoemeraldine (LM) intrinsic oxidation states were assessed through subcutaneous implantation into male Sprague-Dawley rats beneath the dorsal skin, for a period ranging from 19 to 90 weeks. Histological examination, interstitial pressure measurement, and X-ray photoelectron spectroscopy (XPS) were employed to determine the biocompatibility of the polymers. The polymers did not provoke inflammatory responses in the subcutaneous tissues over the entire implantation period. Characteristics features associated with tissue-implant incompatibility were not evident near the implantation. Interstitial pressure was measured to evaluate the development of tissue. Low interstitial pressure readings on the region of implantation confirmed the biocompatibility of these polymer types. The surface composition of the electroactive aniline polymers before and after the implantation was characterized by XPS.

The SCF(HOS/beta-TRCP)-ROC1 E3 ubiquitin ligase utilizes two distinct domains within CUL1 for substrate targeting and ubiquitin ligation

We describe a purified ubiquitination system capable of rapidly catalyzing the covalent linkage of polyubiquitin chains onto a model substrate, phosphorylated IkappaBalpha. The initial ubiquitin transfer and subsequent polymerization steps of this reaction require the coordinated action of Cdc34 and the SCF(HOS/beta-TRCP)-ROC1 E3 ligase complex, comprised of four subunits (Skp1, cullin 1 [CUL1], HOS/beta-TRCP, and ROC1). Deletion analysis reveals that the N terminus of CUL1 is both necessary and sufficient for binding Skp1 but is devoid of ROC1-binding activity and, hence, is inactive in catalyzing ubiquitin ligation. Consistent with this, introduction of the N-terminal CUL1 polypeptide into cells blocks the tumor necrosis factor alpha-induced and SCF-mediated degradation of IkappaB by forming catalytically inactive complexes lacking ROC1. In contrast, the C terminus of CUL1 alone interacts with ROC1 through a region containing the cullin consensus domain, to form a complex fully active in supporting ubiquitin polymerization. These results suggest the mode of action of SCF-ROC1, where CUL1 serves as a dual-function molecule that recruits an F-box protein for substrate targeting through Skp1 at its N terminus, while the C terminus of CUL1 binds ROC1 to assemble a core ubiquitin ligase.