Publications by authors named "Chris Pepper"

100 Publications

Structure-based design of highly selective 2,4,5-trisubstituted pyrimidine CDK9 inhibitors as anti-cancer agents.

Eur J Med Chem 2021 Mar 2;214:113244. Epub 2021 Feb 2.

School of Pharmacy and Biodiscovery Institute, University of Nottingham, University Park, Nottingham, NG7 2RD, UK; Drug Discovery and Development, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5001, Australia. Electronic address:

Cyclin-dependent kinases (CDKs) are a family of Ser/Thr kinases involved in cell cycle and transcriptional regulation. CDK9 regulates transcriptional elongation and this unique property has made it a potential target for several diseases. Due to the conserved ATP binding site, designing selective CDK9 inhibitors has been challenging. Here we report our continued efforts in the optimization of 2,4,5-tri-substituted pyrimidine compounds as potent and selective CDK9 inhibitors. The most selective compound 30m was >100-fold selective for CDK9 over CDK1 and CDK2. These compounds showed broad anti-proliferative activities in various solid tumour cell lines and patient-derived chronic lymphocytic leukaemia (CLL) cells. Decreased phosphorylation of the carboxyl terminal domain (CTD) of RNAPII at Ser-2 and down-regulation of anti-apoptotic protein Mcl-1 were confirmed in both the ovarian cancer model A2780 and patient-derived CLL cells.
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http://dx.doi.org/10.1016/j.ejmech.2021.113244DOI Listing
March 2021

TLR9 expression in Chronic Lymphocytic Leukemia identifies a pro-migratory subpopulation and novel therapeutic target.

Blood 2021 Jan 7. Epub 2021 Jan 7.

Brighton and Sussex Medical School, Falmer, United Kingdom.

CLL remains incurable despite BCR-targeted inhibitors revolutionizing treatment. This suggests that other signaling molecules are involved in disease escape mechanisms and resistance. Toll-like receptor 9 (TLR9) is a promising candidate, which is activated by unmethylated CpG-DNA. Here, we show that plasma from CLL patients contains significantly more unmethylated DNA than plasma from healthy controls (p<0.0001) and that cell-free DNA levels correlate with the prognostic markers CD38, b2-microglobulin and lymphocyte doubling time. Furthermore, elevated cell-free DNA was associated with shorter time to first treatment (TTFT: p=0.003, HR=4.0). We went on to show that TLR9 expression was associated with in-vitro CLL cell migration (p<0.001) and intracellular endosomal TLR9 strongly correlated with aberrant surface expression ((sTLR9); r=0.9). In addition, lymph node-derived CLL cells showed increased sTLR9 (p=0.016) and RNA sequencing of paired sTLR9hi and sTLR9lo CLL cells revealed differential transcription of genes involved in TLR signaling, adhesion, motility and inflammation in sTLR9hi cells. Mechanistically, the TLR9 agonist, ODN2006, promoted CLL cell migration (p<0.001) that was mediated, by p65 NF-kB and STAT3 transcription factor activation. Importantly, autologous plasma induced the same effects, which were reversed by a TLR9 antagonist. Furthermore, high TLR9 expression promoted engraftment and rapid disease progression in a NSG mouse xenograft model. Finally, we showed that dual targeting of TLR9 and BTK was strongly synergistic (median CI=0.2 at ED50), which highlights the distinct role for TLR9 signaling in CLL and the potential for combined targeting of TLR9 and BTK as a more effective treatment strategy in this incurable disease.
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http://dx.doi.org/10.1182/blood.2020005964DOI Listing
January 2021

Managing drug-induced QT prolongation in clinical practice.

Postgrad Med J 2020 Oct 29. Epub 2020 Oct 29.

Cardiology Department, Leeds Teaching Hospitals NHS Trust, Leeds, UK.

Many drug therapies are associated with prolongation of the QT interval. This may increase the risk of Torsades de Pointes (TdP), a potentially life-threatening cardiac arrhythmia. As the QT interval varies with a change in heart rate, various formulae can adjust for this, producing a 'corrected QT' (QTc) value. Normal QTc intervals are typically <450 ms for men and <460 ms for women. For every 10 ms increase, there is a ~5% increase in the risk of arrhythmic events. When prescribing drugs associated with QT prolongation, three key factors should be considered: patient-related risk factors (eg, female sex, age >65 years, uncorrected electrolyte disturbances); the potential risk and degree of QT prolongation associated with the proposed drug; and co-prescribed medicines that could increase the risk of QT prolongation. To support clinicians, who are likely to prescribe such medicines in their daily practice, we developed a simple algorithm to help guide clinical management in patients who are at risk of QT prolongation/TdP, those exposed to QT-prolonging medication or have QT prolongation.
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http://dx.doi.org/10.1136/postgradmedj-2020-138661DOI Listing
October 2020

Transcriptomics-Based Characterization of the Toxicity of ZnO Nanoparticles Against Chronic Myeloid Leukemia Cells.

Int J Nanomedicine 2020 13;15:7901-7921. Epub 2020 Oct 13.

Brighton and Sussex Medical School, University of Sussex, Brighton, UK.

Introduction: Zinc oxide nanoparticles (ZnO NPs) have recently attracted attention as potential anti-cancer agents. To the best of our knowledge, the toxicity of ZnO NPs against human chronic myeloid leukemia cells (K562 cell line) has not been studied using transcriptomics approach.

Objective: The goals of this study were to evaluate the capability of ZnO NPs to induce apoptosis in human chronic myeloid leukemia cells (K562 cells) and to investigate the putative mechanisms of action.

Methods: We used viability assay and flowcytometry coupled with Annexin V-FITC and propidium iodide to investigate the toxicity of ZnO NPs on K562 cells and normal peripheral blood mononuclear cells. Next we utilized a DNA microarray-based transcriptomics approach to characterize the ZnO NPs-induced changes in the transcriptome of K562 cells.

Results: ZnO NPs exerted a selective toxicity (mainly by apoptosis) on the leukemic cells (≤0.005) and altered their transcriptome; 429 differentially expressed genes (DEGs) with fold change (FC)≥4 and ≤0.008 with corrected ≤0.05 were identified in K562 cells post treatment with ZnO NPs. The over-expressed genes were implicated in "response to zinc", "response to toxic substance" and "negative regulation of growth" (corrected ≤0.05). In contrast, the repressed genes positively regulated "cell proliferation", "cell migration", "cell adhesion", "receptor signaling pathway via JAK-STAT" and "phosphatidylinositol 3-kinase signaling" (corrected ≤0.05). Lowering the FC to ≥1.5 with ≤0.05 and corrected ≤0.1 showed that ZnO NPs over-expressed the anti-oxidant defense system, drove K562 cells to undergo mitochondrial-dependent apoptosis, and targeted NF-κB pathway.

Conclusion: Taken together, our findings support the earlier studies that reported anti-cancer activity of ZnO NPs and revealed possible molecular mechanisms employed by ZnO NPs to induce apoptosis in K562 cells.
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http://dx.doi.org/10.2147/IJN.S261636DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7568638PMC
November 2020

Novel pyrrolobenzodiazepine benzofused hybrid molecules inhibit NF-κB activity and synergise with bortezomib and ibrutinib in hematological cancers.

Haematologica 2021 Apr 1;106(4):958-967. Epub 2021 Apr 1.

Brighton and Sussex Medical School, University of Sussex, Brighton, UK.

Chronic lymphocytic leukemia (CLL) and multiple myeloma (MM) are incurable hematological malignancies that are pathologically linked with aberrant NF-κB activation. In this study, we identified a group of novel C8-linked benzofused Pyrrolo[2,1-c][1,4]benzodiazepines (PBD) monomeric hybrids capable of sequence-selective inhibition of NF-κB with low nanomolar LD50 values in CLL (n=46) and MM cell lines (n=5). The lead compound, DC-1-192, significantly inhibited NF-κB DNA binding after just 4h exposure and demonstrating inhibitory effects on both canonical and non-canonical NF-κB subunits. In primary CLL cells, sensitivity to DC-1-192 was inversely correlated with RelA subunit expression (r2=0.2) and samples with BIRC3 or NOTCH1 mutations showed increased sensitivity (P=0.001). RNA-sequencing and gene set enrichment analysis confirmed the over-representation of NF-κB regulated genes in the down-regulated gene list. Furthermore, In vivo efficacy studies in NOD/SCID mice, using a systemic RPMI 8226 human multiple myeloma xenograft model, showed that DC-1-192 significantly prolonged survival (P=0.017). In addition, DC1-192 showed synergy with bortezomib and ibrutinib; synergy with ibrutinib was enhanced when CLL cells were co-cultured on CD40L-expressing fibroblasts in order to mimic the cytoprotective lymph node microenvironment (P = 0.01). Given that NF-κB plays a role in both bortezomib and ibrutinib resistance mechanisms, these data provide a strong rationale for the use of DC-1-192 in the treatment of NF-κB-driven cancers, particularly in the context of relapsed/refractory disease.
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http://dx.doi.org/10.3324/haematol.2019.238584DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8018133PMC
April 2021

Use of a modified stethoscope to assess paediatric nasal airflow in suspected choanal atresia, nasal stents or nasopharyngeal airways.

Clin Otolaryngol 2020 07 20;45(4):654-655. Epub 2020 Apr 20.

Evelina London Children's Hospital, London, UK.

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http://dx.doi.org/10.1111/coa.13534DOI Listing
July 2020

Clinical utility of telomere length measurements in cancer.

Curr Opin Genet Dev 2020 02 25;60:107-111. Epub 2020 Mar 25.

Division of Cancer & Genetics, Cardiff University Medical School, Cardiff, CF14 4XN, United Kingdom.

Cancer remains one of the leading causes of death in the developed world and despite impressive advances in therapeutic modalities, only a small subset of patients are currently cured. The underlying genetic heterogeneity of cancers clearly plays a crucial role in determining both the clinical course of individual pathologies and their responses to standard treatments. Although every tumour is to some extent distinct, there are recurrent features of cancers that can be exploited as therapeutic targets and as prognostic and predictive biomarkers; one such attribute is telomere length. Here we discuss the utility of telomere length evaluation in cancer and describe some of the promise and challenges of bringing this into clinical practice.
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http://dx.doi.org/10.1016/j.gde.2020.02.012DOI Listing
February 2020

Dissecting the role of the CXCL12/CXCR4 axis in acute myeloid leukaemia.

Br J Haematol 2020 06 5;189(5):815-825. Epub 2020 Mar 5.

Brighton and Sussex Medical School, University of Sussex, Brighton, UK.

Acute myeloid leukaemia (AML) is the most common adult acute leukaemia with the lowest survival rate. It is characterised by a build-up of immature myeloid cells anchored in the protective niche of the bone marrow (BM) microenvironment. The CXCL12/CXCR4 axis is central to the pathogenesis of AML as it has fundamental control over AML cell adhesion into the protective BM niche, adaptation to the hypoxic environment, cellular migration and survival. High levels of CXCR4 expression are associated with poor relapse-free and overall survival. The CXCR4 ligand, CXCL12 (SDF-1), is expressed by multiple cells types in the BM, facilitating the adhesion and survival of the malignant clone. Blocking the CXCL12/CXCR4 axis is an attractive therapeutic strategy providing a 'multi-hit' therapy that both prevents essential survival signals and releases the AML cells from the BM into the circulation. Once out of the protective niche of the BM they would be more susceptible to destruction by conventional chemotherapeutic drugs. In this review, we disentangle the diverse roles of the CXCL12/CXCR4 axis in AML. We then describe multiple CXCR4 inhibitors, including small molecules, peptides, or monoclonal antibodies, which have been developed to date and their progress in pre-clinical and clinical trials. Finally, the review leads us to the conclusion that there is a need for further investigation into the development of a 'multi-hit' therapy that targets several signalling pathways related to AML cell adhesion and maintenance in the BM.
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http://dx.doi.org/10.1111/bjh.16456DOI Listing
June 2020

CD49d promotes disease progression in chronic lymphocytic leukemia: new insights from CD49d bimodal expression.

Blood 2020 04;135(15):1244-1254

Division of Hematology, University of Tor Vergata, Rome, Italy.

CD49d is a remarkable prognostic biomarker of chronic lymphocytic leukemia (CLL). The cutoff value for the extensively validated 30% of positive CLL cells is able to separate CLL patients into 2 subgroups with different prognoses, but it does not consider the pattern of CD49d expression. In the present study, we analyzed a cohort of 1630 CLL samples and identified the presence of ∼20% of CLL cases (n = 313) characterized by a bimodal expression of CD49d, that is, concomitant presence of a CD49d+ subpopulation and a CD49d- subpopulation. At variance with the highly stable CD49d expression observed in CLL patients with a homogeneous pattern of CD49d expression, CD49d bimodal CLL showed a higher level of variability in sequential samples, and an increase in the CD49d+ subpopulation over time after therapy. The CD49d+ subpopulation from CD49d bimodal CLL displayed higher levels of proliferation compared with the CD49d- cells; and was more highly represented in the bone marrow compared with peripheral blood (PB), and in PB CLL subsets expressing the CXCR4dim/CD5bright phenotype, known to be enriched in proliferative cells. From a clinical standpoint, CLL patients with CD49d bimodal expression, regardless of whether the CD49d+ subpopulation exceeded the 30% cutoff or not, experienced clinical behavior similar to CD49d+ CLL, both in chemoimmunotherapy (n = 1522) and in ibrutinib (n = 158) settings. Altogether, these results suggest that CD49d can drive disease progression in CLL, and that the pattern of CD49d expression should also be considered to improve the prognostic impact of this biomarker in CLL.
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http://dx.doi.org/10.1182/blood.2019003179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7228464PMC
April 2020

Increased frequency of CD4 PD-1 HLA-DR T cells is associated with disease progression in CLL.

Br J Haematol 2020 03 8;188(6):872-880. Epub 2019 Nov 8.

Division of Cancer and Genetics, Cardiff University School of Medicine, Cardiff, UK.

Chronic lymphocytic leukaemia (CLL) patients often have abnormal expansions of CD4 and CD8 T cells and this can be associated with progressive disease. To characterise the key T-cell populations involved in this phenomenon, we used flow cytometry and 11 phenotypic markers to study 74 CLL patients and 14 controls. T cells of CLL patients were more phenotypically complex than those of healthy controls with significant increases in the frequencies of CD4 and CD8 memory T cells expressing exhaustion-, activation- and senescence-associated markers. Multivariate analysis of 111 different T-cell subsets showed that high frequencies of four subsets (three CD8 and one CD4) were associated with shorter progression-free survival. The most significant association was with CD4 HLA-DR PD-1 T cells, and patients could be stratified into high- and low-risk groups based on the frequency of these T cells. The expansion of this CD4 subset could not be accounted for by age, cytomegalovirus infection or increases in Treg cells. Overall, these results highlight two relatively simple biomarkers, percentage CD8 and percentage CD4 PD-1 HLA-DR T cells, which can be used to risk-stratify CLL patients, independent of other tumour-associated markers. They also provide further evidence for the pivotal role of T cells in modulating the pathology of CLL.
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http://dx.doi.org/10.1111/bjh.16260DOI Listing
March 2020

Targeting CDK9 for treatment of colorectal cancer.

Mol Oncol 2019 10 21;13(10):2178-2193. Epub 2019 Aug 21.

Centre for Drug Discovery and Development, School of Pharmacy and Medical Sciences, University of South Australia Cancer Research Institute, Adelaide, SA, Australia.

Colorectal cancer (CRC) remains one of the most lethal human malignancies, and pursuit of new therapeutic targets for treatment has been a major research focus. Cyclin-dependent kinase 9 (CDK9), which plays a crucial role in transcription, has emerged as a target for cancer treatment. CDKI-73, one of the most potent and pharmacologically superior CDK9 inhibitors, has demonstrated excellent anti-tumour efficacy against several types of cancers. In this study, we evaluated its therapeutic potential against CRC. CDKI-73 elicited high cytotoxicity against all colon cancer cell lines tested. Cell cycle and apoptosis analysis in HCT 116 and HT29 cells revealed that CDKI-73 induced cell death without accumulation of DNA at any phase of the cell cycle. Moreover, it caused depolarisation of mitochondrial membrane, leading to caspase-independent apoptosis. Knockdown by shRNA demonstrated the CDK9-targeted mechanism of CDKI-73, which also affected the Mnk/eIF4E signalling axis. In addition, RT-qPCR analysis showed that CDKI-73 down-regulated multiple pro-survival factors at the mRNA level. Its in vivo anti-tumour efficacy was further evaluated in Balb/c nude mice bearing HCT 116 xenograft tumours. CDKI-73 significantly inhibited tumour growth (***P < 0.001) without overt toxicity. Analysis of the tumour tissues collected from the xenografted animals confirmed that the in vivo anti-tumour efficacy was associated with CDK9 targeting of CDKI-73. Overall, this study provides compelling evidence that CDKI-73 is a promising drug candidate for treating colorectal cancer.
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http://dx.doi.org/10.1002/1878-0261.12559DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6763784PMC
October 2019

Multicentre randomised trial comparing contact force with electrical coupling index in atrial flutter ablation (VERISMART trial).

PLoS One 2019 3;14(4):e0212903. Epub 2019 Apr 3.

Department of Cardiology, Leeds Teaching Hospitals NHS Trust, Leeds General Infirmary, Leeds, United Kingdom.

Introduction: Electrical coupling index (ECI) and contact force (CF) have been developed to aid lesion formation during catheter ablation. ECI measures tissue impedance and capacitance whilst CF measures direct contact. The aim was to determine whether the presence of catheter / tissue interaction information, such as ECI and CF, reduce time to achieve bidirectional cavotricuspid isthmus block during atrial flutter (AFL) ablation.

Methods: Patients with paroxysmal or persistent AFL were randomised to CF visible (range 5-40g), CF not visible, ECI visible (change of 12%) or ECI not visible. Follow-up occurred at 3 and 6 months and included a 7 day ECG recording. The primary endpoint was time to bidirectional cavotricuspid isthmus block.

Results: 114 patients were randomised, 16 were excluded. Time to bidirectional block was significantly shorter when ECI was visible (median 30.0 mins (IQR 31) to median 10.5mins (IQR 12) p 0.023) versus ECI not visible. There was a trend towards a shorter time to bidirectional block when CF was visible. Higher force was applied when CF was visible (median 9.03g (IQR 7.4) vs. 11.3g (5.5) p 0.017). There was no difference in the acute recurrence of conduction between groups. The complication rate was 2%, AFL recurrence was 1.1% and at 6 month follow-up, 12% had atrial fibrillation.

Conclusion: The use of tissue contact information during AFL ablation was associated with reduced time taken to achieve bidirectional block when ECI was visible. Contact force data improved contact when visible with a trend towards a reduction in the procedural endpoint. ClinicalTrials.gov trial identifier: NCT02490033.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0212903PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6447159PMC
December 2019

Is venetoclax a new wonder drug in CLL?

Br J Haematol 2019 05 11;185(4):643-646. Epub 2019 Mar 11.

Brighton and Sussex Medical School, University of Sussex, Brighton, BN1 9PX, UK.

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http://dx.doi.org/10.1111/bjh.15836DOI Listing
May 2019

Telomere fusions associate with coding sequence and copy number alterations in CLL.

Leukemia 2019 08 22;33(8):2093-2097. Epub 2019 Feb 22.

Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, UK.

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http://dx.doi.org/10.1038/s41375-019-0423-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6690834PMC
August 2019

Telomere length predicts for outcome to FCR chemotherapy in CLL.

Leukemia 2019 08 30;33(8):1953-1963. Epub 2019 Jan 30.

Division of Cancer & Genetics, Cardiff University, School of Medicine, Heath Park, Cardiff, UK.

We have previously shown that dividing patients with CLL into those with telomeres inside the fusogenic range (TL-IFR) and outside the fusogenic range (TL-OFR) is powerful prognostic tool. Here, we used a high-throughput version of the assay (HT-STELA) to establish whether telomere length could predict for outcome to fludarabine, cyclophosphamide, rituximab (FCR)-based treatment using samples collected from two concurrent phase II studies, ARCTIC and ADMIRE (n = 260). In univariate analysis, patients with TL-IFR had reduced progression-free survival (PFS) (P < 0.0001; HR = 2.17) and shorter overall survival (OS) (P = 0.0002; HR = 2.44). Bifurcation of the IGHV-mutated and unmutated subsets according to telomere length revealed that patients with TL-IFR in each subset had shorter PFS (HR = 4.35 and HR = 1.48, respectively) and shorter OS (HR = 3.81 and HR = 2.18, respectively). In addition, the OS of the TL-OFR and TL-IFR subsets were not significantly altered by IGHV mutation status (P = 0.61; HR = 1.24 and P = 0.41; HR = 1.47, respectively). In multivariate modeling, telomere length was the dominant co-variable for PFS (P = 0.0002; HR = 1.85) and OS (P = 0.05; HR = 1.61). Taken together, our data suggest that HT-STELA is a powerful predictor of outcome to FCR-based treatment and could be used to inform the design of future risk-adapted clinical trials.
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http://dx.doi.org/10.1038/s41375-019-0389-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6756045PMC
August 2019

Effects of Systematic Shortening of Noncovalent C8 Side Chain on the Cytotoxicity and NF-κB Inhibitory Capacity of Pyrrolobenzodiazepines (PBDs).

J Med Chem 2019 02 13;62(4):2127-2139. Epub 2019 Feb 13.

Institute of Pharmaceutical Science, School of Cancer and Pharmaceutical Sciences , King's College London , London SE1 9NH , U.K.

The systematic shortening of the noncovalent element of a C8-linked pyrrolobenzodiazepine (PBD) conjugate (13) led to the synthesis of a 19-member library of C8-PBD monomers. The critical elements of 13, which were required to render the molecule cytotoxic, were elucidated by an annexin V assay. The effects of shortening the noncovalent element of the molecule on transcription factor inhibitory capacity were also explored through an enzyme-linked immunosorbent assay-based measurement of nuclear NF-κB upon exposure of JJN-3 cells to the synthesized molecules. Although shortening the noncovalent interactive element of 13 had a less than expected effect upon compound cytotoxicity due to reduced DNA interaction, the transcription factor inhibitory capacity of the molecule was notably altered. This study suggests that a relatively short noncovalent side chain at the C8 position of PBD is sufficient to confer cytotoxicity. The shortened PBD monomers provide a new ADC payload scaffold because of their potent cytotoxicity and drug-like properties.
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http://dx.doi.org/10.1021/acs.jmedchem.8b01849DOI Listing
February 2019

PARP inhibition prevents escape from a telomere-driven crisis and inhibits cell immortalisation.

Oncotarget 2018 Dec 25;9(101):37549-37563. Epub 2018 Dec 25.

Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, UK.

Telomeric crisis is the final replicative barrier to cell immortalisation; it is characterised by genome instability and cell death and is triggered when telomeres become critically short and are subjected to fusion. Pre-cancerous lesions, or early stage cancers, often show signs of a telomere crisis, suggesting that escape from telomere crisis is a prerequisite for disease progression. Telomeric crisis therefore represents an attractive, and as yet unexplored, opportunity for therapeutic intervention. Here, we show that two clinically approved PARP inhibitors, selectively eliminate human cells undergoing a telomere-driven crisis. Clonal populations of a colorectal cancer cell line (HCT116), or the plasma cell leukaemia cell line (JJN-3), expressing a dominant-negative telomerase, entered a telomere-driven crisis at defined population doubling points and telomere lengths. The addition of the PARP inhibitors, olaparib or rucaparib prevented these cells from escaping crisis. PARP inhibition did not alter cellular proliferation prior to crisis, rates of telomere erosion or the telomere length at which crisis was initiated, but affected repair of eroded telomeres, resulting in an increased in intra-chromosomal telomere fusion. This was accompanied by enhanced DNA damage checkpoint activation and elevated levels of apoptosis. We propose that PARP inhibitors impair the repair of dysfunctional telomeres and/or induce replicative stress at telomeres to inhibit escape from a telomere crisis. This is the first demonstration that a drug can selectively kill cells experiencing telomeric crisis. We propose that this type of drug, which we term 'crisolytic', has the potential to eliminate pre-cancerous lesions and tumours exhibiting short dysfunctional telomeres.
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http://dx.doi.org/10.18632/oncotarget.26499DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6331021PMC
December 2018

Genetic correlation between multiple myeloma and chronic lymphocytic leukaemia provides evidence for shared aetiology.

Blood Cancer J 2018 12 21;9(1). Epub 2018 Dec 21.

German Cancer Research Center, 69120, Heidelberg, Germany.

The clustering of different types of B-cell malignancies in families raises the possibility of shared aetiology. To examine this, we performed cross-trait linkage disequilibrium (LD)-score regression of multiple myeloma (MM) and chronic lymphocytic leukaemia (CLL) genome-wide association study (GWAS) data sets, totalling 11,734 cases and 29,468 controls. A significant genetic correlation between these two B-cell malignancies was shown (R = 0.4, P = 0.0046). Furthermore, four of the 45 known CLL risk loci were shown to associate with MM risk and five of the 23 known MM risk loci associate with CLL risk. By integrating eQTL, Hi-C and ChIP-seq data, we show that these pleiotropic risk loci are enriched for B-cell regulatory elements and implicate B-cell developmental genes. These data identify shared biological pathways influencing the development of CLL and, MM and further our understanding of the aetiological basis of these B-cell malignancies.
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http://dx.doi.org/10.1038/s41408-018-0162-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6315026PMC
December 2018

Techniques for successful early retrieval of the Micra transcatheter pacing system: A worldwide experience.

Heart Rhythm 2018 06 8;15(6):841-846. Epub 2018 Feb 8.

Division of Cardiovascular Medicine, Department of Internal Medicine, Electrophysiology Section, Ross Heart Hospital, The Ohio State University Wexner Medical Center, Columbus, Ohio. Electronic address:

Background: Experience with retrieval of the Micra transcatheter pacing system (TPS) is limited because of its relatively newer technology. Although abandonment of the TPS at end of life is recommended, certain situations such as endovascular infection or device embolization warrant retrieval.

Objective: The purpose of this study was to report the worldwide experience with successful retrieval of the Micra TPS.

Methods: A list of all successful retrievals of the currently available leadless pacemakers (LPs) was obtained from the manufacturer of Micra TPS. Pertinent details of retrieval, such as indication, days postimplantation, equipment used, complications, and postretrieval management, were obtained from the database collected by the manufacturer. Other procedural details were obtained directly from the operators at each participating site.

Results: Data from the manufacturer consisted of 40 successful retrievals of the Micra TPS. Operators for 29 retrievals (73%) provided the consent and procedural details. Of the 29 retrievals, 11 patients underwent retrieval during the initial procedure (immediate retrieval); the other 18 patients underwent retrieval during a separate procedure (delayed retrieval). Median duration before delayed retrieval was 46 days (range 1-95 days). The most common reason for immediate retrieval was elevated pacing threshold after tether removal. The most common reasons for delayed retrieval included elevated pacing threshold at follow-up, endovascular infection, and need for transvenous device. Mean procedure duration was 63.11 ± 56 minutes. All retrievals involved snaring via a Micra TPS delivery catheter or steerable sheath. No serious complications occurred during the reported retrievals.

Conclusion: Early retrieval of the Micra TPS is feasible and safe.
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http://dx.doi.org/10.1016/j.hrthm.2018.02.008DOI Listing
June 2018

Telomere length is an independent prognostic marker in MDS but not in de novo AML.

Br J Haematol 2017 07 9;178(2):240-249. Epub 2017 May 9.

Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, UK.

Telomere dysfunction is implicated in the generation of large-scale genomic rearrangements that drive progression to malignancy. In this study we used high-resolution single telomere length analysis (STELA) to examine the potential role of telomere dysfunction in 80 myelodysplastic syndrome (MDS) and 95 de novo acute myeloid leukaemia (AML) patients. Despite the MDS cohort being older, they had significantly longer telomeres than the AML cohort (P < 0·0001) where telomere length was also significantly shorter in younger AML patients (age <60 years) (P = 0·02) and in FLT3 internal tandem duplication-mutated AML patients (P = 0·03). Using a previously determined telomere length threshold for telomere dysfunction (3·81 kb) did not provide prognostic resolution in AML [Hazard ratio (HR) = 0·68, P = 0·2]. In contrast, the same length threshold was highly prognostic for overall survival in the MDS cohort (HR = 5·0, P < 0·0001). Furthermore, this telomere length threshold was an independent parameter in multivariate analysis when adjusted for age, gender, cytogenetic risk group, number of cytopenias and International Prognostic Scoring System (IPSS) score (HR = 2·27, P < 0·0001). Therefore, telomere length should be assessed in a larger prospective study to confirm its prognostic role in MDS with a view to integrating this variable into a revised IPSS.
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http://dx.doi.org/10.1111/bjh.14666DOI Listing
July 2017

Telomere length is a critical determinant for survival in multiple myeloma.

Br J Haematol 2017 07 24;178(1):94-98. Epub 2017 Mar 24.

Division of Cancer & Genetics, School of Medicine, Cardiff University, Cardiff, UK.

The variable clinical outcomes of Multiple Myeloma (MM) patients are incompletely defined by current prognostication tools. We examined the clinical utility of high-resolution telomere length analysis as a prognostic marker in MM. Cohort stratification, using a previously determined length threshold for telomere dysfunction, revealed that patients with short telomeres had a significantly shorter overall survival (P < 0·0001; HR = 3·4). Multivariate modelling using forward selection identified International Staging System (ISS) stage as the most important prognostic factor, followed by age and telomere length. Importantly, each ISS prognostic subset could be further risk-stratified according to telomere length, supporting the inclusion of this parameter as a refinement of the ISS.
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http://dx.doi.org/10.1111/bjh.14643DOI Listing
July 2017

Genome-wide association analysis implicates dysregulation of immunity genes in chronic lymphocytic leukaemia.

Nat Commun 2017 02 6;8:14175. Epub 2017 Feb 6.

Department of Haematology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, UK.

Several chronic lymphocytic leukaemia (CLL) susceptibility loci have been reported; however, much of the heritable risk remains unidentified. Here we perform a meta-analysis of six genome-wide association studies, imputed using a merged reference panel of 1,000 Genomes and UK10K data, totalling 6,200 cases and 17,598 controls after replication. We identify nine risk loci at 1p36.11 (rs34676223, P=5.04 × 10), 1q42.13 (rs41271473, P=1.06 × 10), 4q24 (rs71597109, P=1.37 × 10), 4q35.1 (rs57214277, P=3.69 × 10), 6p21.31 (rs3800461, P=1.97 × 10), 11q23.2 (rs61904987, P=2.64 × 10), 18q21.1 (rs1036935, P=3.27 × 10), 19p13.3 (rs7254272, P=4.67 × 10) and 22q13.33 (rs140522, P=2.70 × 10). These new and established risk loci map to areas of active chromatin and show an over-representation of transcription factor binding for the key determinants of B-cell development and immune response.
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http://dx.doi.org/10.1038/ncomms14175DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5303820PMC
February 2017

Genome-wide association analysis of chronic lymphocytic leukaemia, Hodgkin lymphoma and multiple myeloma identifies pleiotropic risk loci.

Sci Rep 2017 01 23;7:41071. Epub 2017 Jan 23.

Division of Molecular Genetic Epidemiology, German Cancer Research Centre, Heidelberg, Germany.

B-cell malignancies (BCM) originate from the same cell of origin, but at different maturation stages and have distinct clinical phenotypes. Although genetic risk variants for individual BCMs have been identified, an agnostic, genome-wide search for shared genetic susceptibility has not been performed. We explored genome-wide association studies of chronic lymphocytic leukaemia (CLL, N = 1,842), Hodgkin lymphoma (HL, N = 1,465) and multiple myeloma (MM, N = 3,790). We identified a novel pleiotropic risk locus at 3q22.2 (NCK1, rs11715604, P = 1.60 × 10) with opposing effects between CLL (P = 1.97 × 10) and HL (P = 3.31 × 10). Eight established non-HLA risk loci showed pleiotropic associations. Within the HLA region, Ser37 + Phe37 in HLA-DRB1 (P = 1.84 × 10) was associated with increased CLL and HL risk (P = 4.68 × 10), and reduced MM risk (P = 1.12 × 10), and Gly70 in HLA-DQB1 (P = 3.15 × 10) showed opposing effects between CLL (P = 3.52 × 10) and HL (P = 3.41 × 10). By integrating eQTL, Hi-C and ChIP-seq data, we show that the pleiotropic risk loci are enriched for B-cell regulatory elements, as well as an over-representation of binding of key B-cell transcription factors. These data identify shared biological pathways influencing the development of CLL, HL and MM. The identification of these risk loci furthers our understanding of the aetiological basis of BCMs.
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http://dx.doi.org/10.1038/srep41071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5253627PMC
January 2017

Tumor cell migration is inhibited by a novel therapeutic strategy antagonizing the alpha-7 receptor.

Oncotarget 2017 Feb;8(7):11414-11424

Neuro-Bio Ltd, Culham Science Centre, Abingdon, OX14 3DB, UK.

A 14mer peptide (T14) derived from the C-terminus of acetylcholinesterase (AChE) selectively activates metastatic breast cancer cells via the alpha-7 nicotinic receptor (α7 nAChR). This naturally occurring peptide is also present in brain, is elevated in Alzheimer's disease, and is antagonised by a cyclized variant (NBP-14). Here we investigated the effects of NBP-14 in six different cancer cell lines, primary leukemia B-cells and normal B-cells. All cells tested expressed α7 nAChR, intracellular and extracellular T14. However, NBP-14 showed low toxicity and weak anti-proliferative effects in the majority of the cell lines and was even less toxic in normal B-cells when compared to primary chronic lymphocytic leukemia cells (P < 0.001). Given the potential role of T14 peptide in metastasis, we next investigated the effects of NBP-14 on tumor cell migration, where it caused a dose-dependent reduction. The extent of NBP-14 inhibition positively correlated with the migration of the cells (r2 = 0.45; P = 0.06). Furthermore, NBP-14 preferentially inhibited the migration of primary leukemia cells when compared with normal B-cells (P = 0.0002); when the normal B-cell data was excluded, this correlation was strengthened (r2 = 0.80; P = 0.006). Importantly, the constitutive α7 nAChR expression positively correlated with intracellular T14 levels (r2 = 0.91; P = 0.0003) and inversely correlated with extracellular T14 levels in the cell culture supernatants (r2 = -0.79; P = 0.034). However, in the presence of NBP-14, α7 nAChR expression was reduced (P = 0.04) and the most migratory cells showed the largest reduction in expression. In conclusion, NBP-14-mediated antagonism of the α7 nAChR offers a novel therapeutic strategy with the potential to inhibit tumor cell migration.
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http://dx.doi.org/10.18632/oncotarget.14545DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5355275PMC
February 2017

Percutaneous left atrial appendage occlusion using different technologies in the United Kingdom: A multicenter registry.

Catheter Cardiovasc Interv 2017 Feb 21;89(3):484-492. Epub 2016 Sep 21.

Royal Brompton & Harefield Hospital NHS Foundation Trust, London, United Kingdom.

Objectives: This study aimed at assessing the feasibility and long-term efficacy of left atrial appendage occlusion (LAAO) in a "real world" setting.

Background: Although LAAO has recently emerged as an alternative to oral anticoagulants in patients with atrial fibrillation for the prevention of thromboembolic stroke, "real world" data about the procedure with different devices are lacking.

Methods: Eight centers in the United Kingdom contributed to a retrospective registry for LAAO procedures undertaken between July 2009 and November 2014.

Results: A total of 371 patients (72.9 ± 8.3 years old, 88.9% males) were enrolled. The overall procedure success was 92.5%, with major events in 3.5% of cases. The device choice was Watchman in 63% of cases, Amplatzer Cardiac Plug in 34.7%, Lariat in 1.7%, and Coherex WaveCrest in 0.6%. A significant improvement in procedure success (from 89.2% to 95.7%; P = 0.018) and reduction of acute major complications (from 6.5% to 0.5%; P = 0.001) were observed between procedures in the first and the second half of the recruitment time. An annual 90.1% relative risk reduction (RRR) for ischemic stroke, an 87.2% thromboembolic events RRR, and a 92.9% major bleeding RRR were observed, if compared with the predicted annual risks based on CHADS2, CHA2DS2-Vasc, and HAS-BLED scores, respectively, over a follow-up period of 24.7 ± 16.07 months.

Conclusions: LAAO can be performed safely in a real world setting with good implant success rates and procedural outcomes. The long-term benefits of the procedure are reassuring in terms of both ischemic events and avoidance of severe bleeding associated with anticoagulation in this patient group. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/ccd.26782DOI Listing
February 2017

Key Molecular Drivers of Chronic Lymphocytic Leukemia.

Clin Lymphoma Myeloma Leuk 2016 11 10;16(11):593-606. Epub 2016 Aug 10.

Institute of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom.

Chronic lymphocytic leukemia (CLL) is an adult neoplastic disease of B cells characterized by variable clinical outcomes. Although some patients have an aggressive form of the disease and often encounter treatment failure and short survival, others have more stable disease with long-term survival and little or no need for theraphy. In the past decade, significant advances have been made in our understanding of the molecular drivers that affect the natural pathology of CLL. The present review describes what is known about these key molecules in the context of their role in tumor pathogenicity, prognosis, and therapy.
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http://dx.doi.org/10.1016/j.clml.2016.08.008DOI Listing
November 2016

Phenotype and immune function of lymph node and peripheral blood CLL cells are linked to transendothelial migration.

Blood 2016 07 1;128(4):563-73. Epub 2016 Jun 1.

Department of Haemato-Oncology, Division of Cancer Studies, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom;

Several lines of evidence suggest that homing of tumor cells to lymphoid tissue contributes to disease progression in chronic lymphocytic leukemia (CLL). Here, we demonstrate that lymph node (LN)-derived CLL cells possess a distinct phenotype, and exhibit enhanced capacity for T-cell activation and superior immune synapse formation when compared with paired peripheral blood (PB) samples. LN-derived CLL cells manifest a proliferative, CXCR4(dim)CD5(bright) phenotype compared with those in the PB and higher expression of T-cell activation molecules including CD80, CD86, and HLA-D-related (DR). In addition, LN-CLL cells have higher expression of α4β1 (CD49d) which, as well as being a co-stimulatory molecule, is required for CLL cells to undergo transendothelial migration (TEM) and enter the proliferation centers of the LNs. Using an in vitro system that models circulation and TEM, we showed that the small population of CLL cells that migrate are CXCR4(dim)CD5(bright) with higher CD49d, CD80, CD86, and HLA-DR compared with those that remain circulating; a phenotype strikingly similar to LN-derived CLL cells. Furthermore, sorted CD49d(hi) CLL cells showed an enhanced capacity to activate T cells compared with CD49d(lo) subpopulations from the same patient. Thus, although PB-CLL cells have a reduced capacity to form immune synapses and activate CD4(+) T cells, this was not the case for LN-CLL cells or those with the propensity to undergo TEM. Taken together, our study suggests that CLL cell immunologic function is not only modulated by microenvironmental interactions but is also a feature of a subpopulation of PB-CLL cells that are primed for lymphoid tissue homing and interaction with T cells.
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http://dx.doi.org/10.1182/blood-2016-01-683128DOI Listing
July 2016

Electrocardiogram interpretation and arrhythmia management: a primary and secondary care survey.

Br J Gen Pract 2016 May 29;66(646):e291-6. Epub 2016 Mar 29.

Leeds General Infirmary; and Leeds Institute for Quality Healthcare, Leeds.

Background: There is increasing desire among service commissioners to treat arrhythmia in primary care. Accurate interpretation of the electrocardiogram (ECG) is fundamental to this. ECG interpretation has previously been shown to vary widely but there is little recent data.

Aim: To examine the interpretation of ECGs in primary and secondary care.

Design And Setting: A cross-sectional survey of participants' interpretation of six ECGs and hypothetical management of patients based on those ECGs, at primary care educational events, and a cardiology department in Leeds.

Method: A total of 262 primary care clinicians and 20 cardiology clinicians were surveyed via questionnaire. Answers were compared with expert electrophysiologist opinion.

Results: In primary care, abnormal ECGs were interpreted as normal by 23% of responders. ST elevation and prolonged QT were incorrectly interpreted as normal by 1% and 22%, respectively. In cardiology, abnormal ECGs were interpreted as normal by 3%.

Conclusion: ECG provision and interpretation remains inconsistent in both primary and secondary care. Primary care practitioners are less experienced and less confident with ECG interpretation than cardiologists, and require support in this area.
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http://dx.doi.org/10.3399/bjgp16X684781DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4838440PMC
May 2016

A CD21 low phenotype, with no evidence of autoantibodies to complement proteins, is consistent with a poor prognosis in CLL.

Oncotarget 2015 Oct;6(32):32669-80

Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK.

B-cell chronic lymphocytic leukemia (CLL) is characterized by differential BCR signaling and autoimmune complications. Complement modulates B-cell function via C3d and CD21 cross-linked to the B-cell receptor (BCR). We hypothesized that CD21 contributes to BCR signaling and participates in the autoimmunity associated with CLL. We analyzed CD21 expression on 106 CLL patient samples and matched serum from 50 patients for the presence of soluble CD21 and autoantibodies to CR2, CR1, MCP and FH. CD21 expression on CLL B-cells was significantly lower than that expressed on B-cells from age-matched controls (P < 0.0001) and was inversely correlated with soluble CD21 (r2 = -0.41). We found no evidence of autoantibody to any complement regulator. Low CD21 expression correlated to prognostic subsets of CLL patients, i.e. cases with unmutated IGHV genes (P = 0.0006), high CD38 (P = 0.02) and high ZAP70 expression (P = 0.0017). Low CD21 expression was inversely correlated to the levels of phosphotyrosine induced in CLL cells following BCR ligation with αIgM (r2 = -0.21). Importantly, lower CD21 expression was also predictive for reduced overall survival (P = 0.005; HR = 2.7). In conclusion, we showed that reduced expression of CD21 on CLL B-cells appears functionally relevant and was associated with poor clinical outcomes.
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http://dx.doi.org/10.18632/oncotarget.5404DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4741721PMC
October 2015

Understanding cancer cell survival is key to patient survival.

Lancet Oncol 2015 Feb;16(2):122-4

Cardiff CLL Research Group, School of Medicine, Heath Park, Cardiff, CF14 4XN, UK.

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http://dx.doi.org/10.1016/S1470-2045(15)70003-3DOI Listing
February 2015