Regeneration linked miRNA modify tumor phenotype and can enforce multi-lineage growth arrest in vivo.

Regulated cell proliferation is an effector mechanism of regeneration, whilst dysregulated cell proliferation is a feature of cancer. We have previously identified microRNA (miRNA) that regulate successful and failed human liver regeneration. We hypothesized that these regulators may directly modify tumor behavior. Here we show that inhibition of miRNAs -503 and -23a, alone or in combination, enhances tumor proliferation in hepatocyte and non-hepatocyte derived cancers in vitro, driving more aggressive tumor behavior in vivo. Inhibition of miRNA-152 caused induction of DNMT1, site-specific methylation with associated changes in gene expression and in vitro and in vivo growth inhibition. Enforced changes in expression of two miRNA recapitulating changes observed in failed regeneration led to complete growth inhibition of multi-lineage cancers in vivo. Our results indicate that regulation of regeneration and tumor aggressiveness are concordant and that miRNA-based inhibitors of regeneration may constitute a novel treatment strategy for human cancers.

Evaluation of the New American Urological Association Guidelines Risk Classification for Hematuria.

PURPOSE: Microhematuria is a prevalent condition and the American Urological Association has developed a new risk-stratified approach for the evaluation of patients with microhematuria. Our objective was to provide the first evaluation of this important guideline. MATERIALS AND METHODS: This multinational cohort study combines contemporary patients from 5 clinical trials and 2 prospective registries who underwent urological evaluation for hematuria. Patients were stratified into American Urological Association risk strata (low, intermediate or high risk) based on sex, age, degree of hematuria, and smoking history. The primary end point was the incidence of bladder cancer within each risk stratum. RESULTS: A total of 15,779 patients were included in the analysis. Overall, 727 patients (4.6%) were classified as low risk, 1,863 patients (11.8%) were classified as intermediate risk, and 13,189 patients (83.6%) were classified as high risk. The predominance of high risk patients was consistent across all cohorts. A total of 857 bladder cancers were diagnosed with a bladder cancer incidence of 5.4%. Bladder cancer was more prevalent in men, smokers, older patients and patients with gross hematuria. The cancer incidence for low, intermediate and high risk groups was 0.4% (3 patients), 1.0% (18 patients) and 6.3% (836 patients), respectively. CONCLUSIONS: The new risk stratification system separates hematuria patients into clinically meaningful categories with differing likelihoods of bladder cancer that would justify evaluating the low, intermediate and high risk groups with incremental intensity. Furthermore, it provides the relative incidence of bladder cancer in each risk group which should facilitate patient counseling regarding the risks and benefits of evaluation for bladder cancer.

Lentiviral Vector Purification Using Genetically Encoded Biotin Mimic in Packaging Cell.

Lentiviral vectors (LVs) have recently witnessed an increasing demand in research and clinical applications. Their current purification processes represent the main bottleneck in their widespread use, as the methods used are cumbersome and yield low recoveries. We aimed to develop a one-step method to specifically purify LVs, with high yields and reduced levels of impurities, using the biotin-streptavidin system. Herein, packaging HEK293T cells were genetically engineered with a cyclical biotin-mimicking peptide displayed on a CD8α stalk, termed cTag8. LVs were modified with cTag8 by its passive incorporation onto viral surfaces during budding, without viral protein engineering or hindrance on infectivity. Expression of cTag8 on LVs allowed complete capture of infectious particles by streptavidin magnetic beads. As cTag8 binds streptavidin in the nanomolar range, the addition of micromolar concentrations of biotin resulted in the release of captured LVs by competitive elution, with overall yields of ≥60%. Analysis of eluted LVs revealed high purity with a >3-log and 2-log reduction in DNA contamination and host cell proteins, respectively. This one-step purification was also tested for scalable vector processing using monolith affinity chromatography, with an encouraging preliminary overall yield of 20%. This method will be of valuable use for both research and clinical applications of LVs.

miR-181c-BRK1 axis plays a key role in actin cytoskeleton-dependent T cell function.

MicroRNAs are short endogenous noncoding RNAs that play pivotal roles in a diverse range of cellular processes. The miR-181 family is important in T cell development, proliferation, and activation. In this study, we have identified BRK1 as a potential target of miR-181c using a dual selection functional assay and have showed that miR-181c regulates BRK1 by translational inhibition. Given the importance of miR-181 in T cell function and the potential role of BRK1 in the involvement of WAVE2 complex and actin polymerization in T cells, we therefore investigated the influence of miR-181c-BRK1 axis in T cell function. Stimulation of PBMC derived CD3+ T cells resulted in reduced miR-181c expression and up-regulation of BRK1 protein expression, suggesting that miR-181c-BRK1 axis is important in T cell activation. We further showed that overexpression of miR-181c or suppression of BRK1 resulted in inhibition of T cell activation and actin polymerization coupled with defective lamellipodia generation and immunological synapse formation. Additionally, we found that BRK1 silencing led to reduced expressions of other proteins in the WAVE2 complex, suggesting that the impairment of T cell actin dynamics was a result of the instability of the WAVE2 complex following BRK1 depletion. Collectively, we demonstrated that miR-181c reduces BRK1 protein expression level and highlighted the important role of miR-181c-BRK1 axis in T cell activation and actin polymerization-mediated T cell functions.

Clinical utility of a non-invasive urine test for risk assessing patients with no obvious benign cause of hematuria: a physician-patient real world data analysis.

BACKGROUND: The non-invasive Cxbladder urine test system has demonstrated clinical utility in ruling out urothelial carcinoma (UC) in patients with asymptomatic microscopic hematuria (AMH), suggesting that the number of invasive diagnostic tests, including cystoscopy, used in this patient population may be reduced by Cxbladder testing prior to conducting a full urological work-up. The aim of this study was to demonstrate the enhanced clinical utility of communicating objective information on diagnostic decisions made by individual physicians on individual patients with AMH. METHODS: Three hundred ninety-six physician-patient decisions were generated from twelve participant physicians evaluating real world case notes from the same 33 patients presenting with AMH. Each physician reviewed and recommended diagnostic tests and procedures based on each patient's referral data and then re-evaluated their clinical recommendation following disclosure of the non-invasive Cxbladder urine test result. Changes assessed were the total number of requested diagnostic procedures and the number of invasive procedures, including cystoscopy, following addition of information from Cxbladder in the Triage and Triage and Detect modalities. RESULTS: Physicians made significant changes to their diagnostic behavior for patients with AMH when presented with Cxbladder test results, including a reduction in the number of total and invasive procedures including cystoscopy for individuals identified as having a low probability of UC. The intensity of investigation was targeted and increased, including use of total procedures and cystoscopy, for patients identified by Cxbladder tests as having a high probability of UC: urologists increased the level of investigation for both total procedures and invasive procedures. The outcome resulted in patients with a high risk of UC receiving appropriate guideline-recommended invasive diagnostic tests. Patients who tested negative were offered fewer and significantly less invasive procedures. This change in physician behavior results in an increased clinical and patient utility, lower risk of missed UC and invasive test-related harm incidents. CONCLUSIONS: This study demonstrated the potential for increased clinical resolution and significantly enhanced patient management, when physicians consider Cxbladder test results in their clinical evaluation. The change in physician behavior led to more appropriate diagnostic procedure selection and resource allocation to the benefit of both patients and healthcare systems.

Clinical Utility of Cxbladder Monitor for Patients with a History of Urothelial Carcinoma: A Physician-Patient Real-World Clinical Data Analysis.

INTRODUCTION: International guidelines advocate regular surveillance of patients following urothelial carcinoma (UC). A validated molecular diagnostic non-invasive urine test, Cxbladder Monitor, correctly identifies patients with a UC history who have low-probability of recurrence. The present study assesses the clinical utility of Cxbladder Monitor in reducing the number and frequency of urologic procedures ordered without missing detection of recurrent UC. METHODS: Data from 828 physician-patient assessments were generated from 18 participant physicians who each evaluated the same real-world clinical case data for 30 patients undergoing surveillance for recurrent UC. Each physician ordered tests and procedures and their timing, following review of the patient's demographic data, pre-existing conditions, risk factors and clinical history before and after disclosure of Cxbladder Monitor results. Changes in the number, type and timing of procedures ordered were assessed. RESULTS: The addition of Cxbladder Monitor significantly reduced the overall number of tests ordered by 38.7%, including flexible cystoscopy by 43%, for patients whose Cxbladder Monitor result was low-probability. When the result was elevated-probability, the number of procedures ordered, including cystoscopy, was increased consistent with the increased risk of recurrent UC. Importantly, based on the tests ordered by each physician for each of the patients, all cases of recurrent UC would have been detected. CONCLUSION: The increase in clinical utility of Cxbladder Monitor for the management of patients undergoing surveillance for recurrent UC was shown to be driven by the reduction in procedures ordered for low-probability patients and for the more invasive procedures ordered for elevated-probability patients. In this study, the total number of procedures ordered, including the number of cystoscopies, was reduced especially in patients with low-probability of UC. The invasive procedures were ordered in a more targeted fashion for elevated-probability patients, without compromising the detection of recurrent UC. CLINICALTRIALS. GOV IDENTIFIER: NCT02700659. FUNDING: Pacific Edge Limited.

Retroviral insertional mutagenesis implicates E3 ubiquitin ligase RNF168 in the control of cell proliferation and survival.

The E3 ubiquitin ligase RNF168 is a ring finger protein that has previously been identified to play an important regulatory role in the repair of double-strand DNA breaks.  In the present study, an unbiased forward genetics functional screen in mouse granulocyte/ macrophage progenitor cell line FDCP1 has identified E3 ubiquitin ligase RNF168 as a key regulator of cell survival and proliferation. Our data indicate that RNF168 is an important component of the mechanisms controlling cell fate, not only in human and mouse haematopoietic growth factor-dependent cells, but also in the human breast epithelial cell line MCF-7. These observations therefore suggest that RNF168 provides a connection to key pathways controlling cell fate, potentially through interaction with PML nuclear bodies and/or epigenetic control of gene expression. Our study is the first to demonstrate a critical role for RNF168 in the in the mechanisms regulating cell proliferation and survival, in addition to its well-established role in DNA repair.

Clinical comparison of noninvasive urine tests for ruling out recurrent urothelial carcinoma.

OBJECTIVE: Patients with urothelial carcinoma (UC) undergo rigorous surveillance for recurrence. Noninvasive urine tests are not currently recommended by guideline panels owing to insufficient clinical benefit. The objective of this study was to prospectively compare the performance of the Cxbladder Monitor test to other commonly available urine markers and cytology for surveillance of patients with UC. METHODS AND MATERIALS: A total of 1,036 urine samples were collected from 803 patients undergoing surveillance for UC. Of these, 1,016 samples were directly assessed using cytology, NMP22 Bladderchek and NMP22 enzyme-linked immunosorbent assay (ELISA), and the clinically validated Cxbladder Monitor test. An exploratory analysis was also performed comparing data from 157 samples where UroVysion fluorescence in situ hybridization analysis was performed locally. RESULTS: The sensitivity of Cxbladder Monitor (0.91) significantly outperformed cytology (0.22), NMP22 ELISA (0.26), and NMP22 BladderChek (0.11). The negative predictive value of Cxbladder Monitor was also superior at 0.96 compared with cytology (0.87), NMP22 ELISA (0.87), and NMP22 BladderChek (0.86). All false-negative results (n = 14) observed using Cxbladder Monitor were also negative for cytology, NMP22 ELISA, and NMP22 BladderChek. In the more limited set, UroVysion fluorescence in situ hybridization also had inferior sensitivity (0.33) and negative predictive value (0.92). CONCLUSIONS: The Cxbladder Monitor test significantly outperforms current Food and Drug Administration-approved urine-based monitoring tests, as well as cytology, in a large representative population undergoing surveillance for recurrent UC. This supports using Cxbladder Monitor as a confirmatory negative adjunct to cystoscopy or to justify postponing cystoscopic investigations in patients with a low risk of recurrence.

Clinical Utility of Cxbladder for the Diagnosis of Urothelial Carcinoma.

INTRODUCTION: This study aimed to demonstrate the clinical utility of non-invasive multigene Cxbladder urine tests in reducing the overall number of diagnostic tests and invasive procedures used in the clinical evaluation of patients presenting with microhematuria, a key symptom of urothelial carcinoma (UC). There is a belief that using non-invasive molecular diagnostic tests in patients with hematuria may lead to patients undergoing unnecessary and costly invasive procedures that can cause adverse events and decrease patient quality of life. The objective of this study was to determine whether or not this was the case, using Cxbladder. METHODS: Data from 396 patient-by-urologist interactions generated 792 decision points from a standardized cohort of 33 patients evaluated by 12 urologists. Participant physicians recommended a selection of tests and procedures based on referral data, then reviewed and amended their recommendations in the context of diagnostic information from Cxbladder used in the Triage and Triage and Detect clinical modalities. RESULTS: All urologists changed their diagnostic behavior in at least one patient case with the addition of Cxbladder results. The total number of diagnostic procedures was reduced by 5% and 25% following disclosure of results from Cxbladder in the Triage and the Triage and Detect modalities, respectively. The total number of requested invasive procedures was reduced from 425 at referral to 379 (-11%) and 292 (-31%) following disclosure of Cxbladder information in the Triage and Triage and Detect modalities, respectively. CONCLUSIONS: Urologists made compelling changes to their clinical decision-making when they were provided with Cxbladder results for patients presenting with hematuria. Cxbladder provides an increase in clinical utility by focusing the use of invasive diagnostic procedures to appropriate patients, reducing both the total number and number of invasive procedures used in the clinical management of patients with hematuria, thereby improving the diagnostic experience and outcomes for patients. FUNDING: Pacific Edge Ltd.

FLT3 and JAK2 Mutations in Acute Myeloid Leukemia Promote Interchromosomal Homologous Recombination and the Potential for Copy Neutral Loss of Heterozygosity.

Acquired copy neutral LOH (CN-LOH) is a frequent occurrence in myeloid malignancies and is often associated with resistance to standard therapeutic modalities and poor survival. Here, we show that constitutive signaling driven by mutated FLT3 and JAK2 confers interchromosomal homologous recombination (iHR), a precedent for CN-LOH. Using a targeted recombination assay, we determined significant iHR activity in internal tandem duplication FLT3 (FLT3-ITD) and JAK2V617F-mutated cells. Sister chromatid exchanges, a surrogate measure of iHR, was significantly elevated in primary FLT3-ITD normal karyotype acute myeloid leukemia (NK-AML) compared with wild-type FLT3 NK-AML. HR was harmonized to S phase of the cell cycle to repair broken chromatids and prevent iHR. Increased HR activity in G0 arrested primary FLT3-ITD NK-AML in contrast to wild-type FLT3 NK-AML. Cells expressing mutated FLT3-ITD demonstrated a relative increase in mutation frequency as detected by thymidine kinase (TK) gene mutation assay. Moreover, resistance was associated with CN-LOH at the TK locus. Treatment of FLT3-ITD- and JAK2V617F-mutant cells with the antioxidant N-acetylcysteine diminished reactive oxygen species (ROS), restoring iHR and HR levels. Our findings show that mutated FLT3-ITD and JAK2 augment ROS production and HR, shifting the cellular milieu toward illegitimate recombination events such as iHR and CN-LOH. Therapeutic reduction of ROS may thus prevent leukemic progression and relapse in myeloid malignancies. Cancer Res; 77(7); 1697-708. ©2017 AACR.

Performance Characteristics of a Multigene Urine Biomarker Test for Monitoring for Recurrent Urothelial Carcinoma in a Multicenter Study.

PURPOSE: Urothelial carcinoma is associated with a high rate of recurrence. Guidelines recommend rigorous, regular surveillance programs that are invasive and expensive. This study describes a noninvasive urine test with sufficient sensitivity to rule out recurrent urothelial carcinoma, thereby reducing invasive diagnostic evaluations without compromising patient care. METHODS AND MATERIALS: A total of 1,036 urine samples were prospectively collected from 763 patients undergoing routine surveillance for recurrent urothelial carcinoma of the bladder. The purpose was to develop and validate a test with combined high sensitivity and high negative predictive value. Cxbladder Monitor combines gene expression, clinical and patient data, and it is designed to rule out the presence of recurrent urothelial carcinoma. RESULTS: Cxbladder Monitor showed an internally validated sensitivity of 0.93 with a negative predictive value of 0.97 and a test negative rate of 0.34. Sensitivity was 0.95 for recurrent disease with a high risk of progression (all high grade disease and low grade, stage T1 or greater disease) compared with 0.86 for low grade Ta disease. Subgroup analyses indicated that diagnostic performance was not significantly different in different age groups, or by gender or tumor stage. Sensitivity was not affected by adjuvant bacillus Calmette-Guérin treatment within the last 6 months. False-negative findings were reported in fewer than 1.5% of all samples collected. CONCLUSIONS: The Cxbladder Monitor test offers combined high sensitivity and high negative predictive value to rule out urothelial carcinoma. This test has clinical utility as a confirmatory negative adjunct to cystoscopy, potentially justifying the postponement/avoidance of cystoscopic investigations to monitor recurrence in patients.

ASH1L (a histone methyltransferase protein) is a novel candidate globin gene regulator revealed by genetic study of an English family with beta-thalassaemia unlinked to the beta-globin locus.

In 1993, we described an English family with beta-thalassaemia that was not linked to the beta-globin locus. Whole genome sequence analyses revealed potential causative mutations in 15 different genes, of which 4 were consistently and uniquely associated with the phenotype in all 7 affected family members, also confirmed by genetic linkage analysis. Of the 4 genes, which are present in a centromeric region of chromosome 1, ASH1L was proposed as causative through functional mRNA knock-down and chromatin-immunoprecipitation studies in human erythroid progenitor cells. Our data suggest a putative role for ASH1L (Trithorax protein) in the regulation of globin genes.

RPL27A is a target of miR-595 and may contribute to the myelodysplastic phenotype through ribosomal dysgenesis.

We investigated the functional consequences following deletion of a microRNA (miR) termed miR-595 which resides on chromosome 7q and is localised within one of the commonly deleted regions identified for Myelodysplasia (MDS) with monosomy 7 (-7)/isolated loss of 7q (7q-). We identified several targets for miR-595, including a large ribosomal subunit protein RPL27A. RPL27A downregulation induced p53 activation, apoptosis and inhibited proliferation. Moreover, p53-independent effects were additionally identified secondary to a reduction in the ribosome subunit 60s. We confirmed that RPL27A plays a pivotal role in the maintenance of nucleolar integrity and ribosomal synthesis/maturation. Of note, RPL27A overexpression, despite showing no significant effects on p53 mRNA levels, did in fact enhance cellular proliferation. In normal CD34+ cells, RPL27A knockdown preferentially blocked erythroid proliferation and differentiation. Lastly, we show that miR-595 expression appears significantly downregulated in the majority of primary samples derived from MDS patients with (-7)/(7q-), in association with RPL27A upregulation. This significant downregulation of miR-595 is also apparent when higher risk MDS cases are compared to lower risk cases. The potential clinical importance of these findings requires further validation.

A holistic comparative analysis of diagnostic tests for urothelial carcinoma: a study of Cxbladder Detect, UroVysion® FISH, NMP22® and cytology based on imputation of multiple datasets.

BACKGROUND: Comparing the relative utility of diagnostic tests is challenging when available datasets are small, partial or incomplete. The analytical leverage associated with a large sample size can be gained by integrating several small datasets to enable effective and accurate across-dataset comparisons. Accordingly, we propose a methodology for a holistic comparative analysis and ranking of cancer diagnostic tests through dataset integration and imputation of missing values, using urothelial carcinoma (UC) as a case study. METHODS: Five datasets comprising samples from 939 subjects, including 89 with UC, where up to four diagnostic tests (cytology, NMP22®, UroVysion® Fluorescence In-Situ Hybridization (FISH) and Cxbladder Detect) were integrated into a single dataset containing all measured records and missing values. The tests were firstly ranked using three criteria: sensitivity, specificity and a standard variable (feature) ranking method popularly known as signal-to-noise ratio (SNR) index derived from the mean values for all subjects clinically known to have UC versus healthy subjects. Secondly, step-wise unsupervised and supervised imputation (the latter accounting for the 'clinical truth' as determined by cystoscopy) was performed using personalized modelling, k-nearest-neighbour methods, multiple logistic regression and multilayer perceptron neural networks. All imputation models were cross-validated by comparing their post-imputation predictive accuracy for UC with their pre-imputation accuracy. Finally, the post-imputation tests were re-ranked using the same three criteria. RESULTS: In both measured and imputed data sets, Cxbladder Detect ranked higher for sensitivity, and urine cytology a higher specificity, when compared with other UC tests. Cxbladder Detect consistently ranked higher than FISH and all other tests when SNR analyses were performed on measured, unsupervised and supervised imputed datasets. Supervised imputation resulted in a smaller cross-validation error. Cxbladder Detect was robust to imputation showing a 2% difference in its predictive versus clinical accuracy, outperforming FISH, NMP22 and cytology. CONCLUSION: All data analysed, pre- and post-imputation showed that Cxbladder Detect had higher SNR and outperformed all other comparator tests, including FISH. The methodology developed and validated for comparative ranking of the diagnostic tests for detecting UC, may be further applied to other cancer diagnostic datasets across population groups and multiple datasets.

A segregation index combining phenotypic (clinical characteristics) and genotypic (gene expression) biomarkers from a urine sample to triage out patients presenting with hematuria who have a low probability of urothelial carcinoma.

BACKGROUND: Hematuria can be symptomatic of urothelial carcinoma (UC) and ruling out patients with benign causes during primary evaluation is challenging. Patients with hematuria undergoing urological work-ups place significant clinical and financial burdens on healthcare systems. Current clinical evaluation involves processes that individually lack the sensitivity for accurate determination of UC. Algorithms and nomograms combining genotypic and phenotypic variables have largely focused on cancer detection and failed to improve performance. This study aimed to develop and validate a model incorporating both genotypic and phenotypic variables with high sensitivity and a high negative predictive value (NPV) combined to triage out patients with hematuria who have a low probability of having UC and may not require urological work-up. METHODS: Expression of IGFBP5, HOXA13, MDK, CDK1 and CXCR2 genes in a voided urine sample (genotypic) and age, gender, frequency of macrohematuria and smoking history (phenotypic) data were collected from 587 patients with macrohematuria. Logistic regression was used to develop predictive models for UC. A combined genotypic-phenotypic model (G + P INDEX) was compared with genotypic (G INDEX) and phenotypic (P INDEX) models. Area under receiver operating characteristic curves (AUC) defined the performance of each INDEX: high sensitivity, NPV >0.97 and a high test-negative rate was considered optimal for triaging out patients. The robustness of the G + P INDEX was tested in 40 microhematuria patients without UC. RESULTS: The G + P INDEX offered a bias-corrected AUC of 0.86 compared with 0.61 and 0.83, for the P and G INDEXs respectively. When the test-negative rate was 0.4, the G + P INDEX (sensitivity = 0.95; NPV = 0.98) offered improved performance compared with the G INDEX (sensitivity = 0.86; NPV = 0.96). 80% of patients with microhematuria who did not have UC were correctly triaged out using the G + P INDEX, therefore not requiring a full urological work-up. CONCLUSION: The adoption of G + P INDEX enables a significant change in clinical utility. G + P INDEX can be used to segregate hematuria patients with a low probability of UC with a high degree of confidence in the primary evaluation. Triaging out low-probability patients early significantly reduces the need for expensive and invasive work-ups, thereby lowering diagnosis-related adverse events and costs.

Faster generation of hiPSCs by coupling high-titer lentivirus and column-based positive selection.

The protocols described here address methods used in two crucial stages in the retroviral reprogramming of somatic cells to produce human induced pluripotent stem cell (hiPSC) lines. The first is an optimized method for producing lentivirus at an efficiency 600-fold greater than previously published, and it includes conjugation of the lentivirus to streptavidin superparamagnetic particles; this process takes 8 d. The second method enables the isolation of true hiPSCs immediately after somatic cell reprogramming and involves column-based positive selection of cells expressing the pluripotency marker TRA-1-81. This process takes 2 h and, as it is directly compatible with feeder-free culture, the time burden of manually identifying and mechanically propagating hiPSC colonies is reduced drastically. Taken together, these methods accelerate the production of hiPSCs and enable lines to be isolated, expanded to approxiamtely 107 cells and cryopreserved within 6-8 weeks.

Two new protocols to enhance the production and isolation of human induced pluripotent stem cell lines.

There are two critical stages in the retroviral reprogramming of somatic cells to produce human induced pluripotent stem cell (hiPSC) lines. One is the production of high titer virus required to reprogram somatic cells; the other is identification of true hiPSC colonies from heterogeneous cell populations, and their isolation and expansion to generate a sustainable, pluripotent stem cell line. Here we describe simple, time-saving methods to address the current difficulties at these two critical junctures. First, we have developed a method to increase the number of infectious viral units 600-fold. Second, we have developed a TRA-1-81-based positive selection column method for isolating "true" hiPSCs from the heterogeneous cell populations, which overcomes the labor-intensive and highly subjective method of manual selection of hiPSC colonies. We have used these techniques to produce 8 hiPSC lines from human fibroblasts and we believe that they are of considerable utility to researchers in the hiPSC field.

Affinity recovery of lentivirus by diaminopelargonic acid mediated desthiobiotin labelling.

Desthiobiotin-tagged lentiviral vectors have been metabolically produced by DBL producer cells in a 7,8-diaminopelargonic acid (7-DAPA) dependent manner for envelope independent, single-step affinity purification. 7-DAPA, which has little or no affinity for avidin/streptavidin, was synthesised and verified by NMR spectroscopy and mass spectrometry. By expressing the biotin acceptor, biotin ligase and desthiobiotin synthase bioD, DBL cells converted exogenous 7-DAPA into membrane-bound desthiobiotin. Desthiobiotin on the DBL cell surface was visualised by confocal microscopy and the desthiobiotin density was quantified by HABA-avidin assay. Desthiobiotin was then spontaneously incorporated onto the surface of lentiviral vectors produced by the DBL cells. It has been demonstrated by flow cytometry that the desthiobiotinylated lentiviruses were captured from the crude 7-DAPA-containing viral supernatant by Streptavidin Magnespheres and eluted by biotin solution efficiently whilst retaining infectivity. The practical, high yielding virus purification using Pierce monomeric avidin coated columns indicates a highly efficient biotin-dependent recovery of infectious lentiviruses at 68%. The recovered lentiviral vectors had a high purity and the majority were eluted within 45 min. This 7-DAPA mediated desthiobiotinylation technology can be applied in scalable production of viral vectors for clinical gene therapy.

Human CD80/IL2 lentivirus-transduced acute myeloid leukaemia (AML) cells promote natural killer (NK) cell activation and cytolytic activity: implications for a phase I clinical study.

Immunotherapeutic strategies may promote T and/or natural killer (NK) cell cytotoxicity. NK cells have the potential to exert a powerful anti-leukaemia effect, as demonstrated by studies of allogeneic transplantation. We have previously shown that CD80/interleukin 2 (IL2) lentivirus (LV)-transduced AML cells stimulate in-vitro T cell activation. The present study demonstrated that allogeneic and autologous culture of peripheral blood mononuclear cells with CD80/IL2-expressing AML cells also promoted NK cell cytotoxicity. Expression of the activation receptors NKp30, NKp44, CD244, CD25, CD69 and HLA-DR significantly increased following allogeneic culture and a consistent increased expression of NKp30, NKp44, NKp46, NKG2D, NKG2C and CD69, and up-regulation of the cytolytic marker CD107a was detected following autologous culture with LV-CD80/IL2 AML cells. Furthermore, increased NK cell lysis of K562 and primary AML blasts was detected. The lytic activity increased by twofold against K562 (from 46.6% to 90.4%) and allogeneic AML cells (from 11.8% to 20.1%) following in-vitro stimulation by CD80/IL2-expressing AML cells. More importantly for potential therapeutic applications, lysis of primary AML cells by autologous NK cells increased by more than 40-fold (from 0.4% to 22.5%). These studies demonstrated that vaccination of patients with CD80/IL2-transduced AML cells could provide a powerful strategy for T/NK cell-mediated stimulation of anti-leukaemic immunological responses.

Simple magnetic cell patterning using streptavidin paramagnetic particles.

A simple methodology for cell patterning has been developed that can potentially be used to position different types of mammalian cells with high precision. In this method, cell membrane proteins were first biotinylated and then bound to streptavidin paramagnetic particles. The magnetically labeled cells were then seeded onto culture dishes and patterned using low magnetic fields. Highly defined cell patterns were achieved using HeLa, TE671 cells and human monocytes. HeLa and TE671 cells were also sequentially patterned and successfully co-cultured on the same plate using this technique. Cell viability studies proved that this magnetic labeling method was not toxic to cells. Transmission electron microscopy showed that the magnetically labeled HeLa and TE671 cells internalized some of the paramagnetic particles after two days of culture, while the labeled human monocytes did the same after only one hour. Uptake of these particles did not affect the cell patterning and cell viability. This magnetic labeling process is fast, as it involves affinity-based attachment of paramagnetic particles and does not rely on cellular uptake of magnetic materials. It may be adaptable and scalable for various applications.