Enhanced Cytotoxicity on Cancer Cells by Combinational Treatment of PARP Inhibitor and 5-Azadeoxycytidine Accompanying Distinct Transcriptional Profiles.

Poly(ADP-ribose) polymerase (PARP) is involved in DNA repair and chromatin regulation. 5-Aza-2'-deoxycytidine (5-aza-dC) inhibits DNA methyltransferases, induces hypomethylation, blocks DNA replication, and causes DNA single strand breaks (SSBs). As the PARP inhibitor is expected to affect both DNA repair and transcriptional regulations, we investigated the effect of combinational use of PARP inhibitors on cytotoxicity of 5-aza-dC in human cancer cell lines. The combinational treatment of 5-aza-dC and PARP inhibitor PJ-34 exhibited a stronger cytotoxicity compared with their treatment alone in blood cancer HL-60, U937, and colon cancer HCT116 and RKO cells. Treatment with 5-aza-dC but not PJ-34 caused SSBs in HCT116 cell lines. Global genome DNA demethylation was observed after treatment with 5-aza-dC but not with PJ-34. Notably, in microarray analysis, combinational treatment with PJ-34 and 5-aza-dC caused dissimilar broad changes in gene expression profiles compared with their single treatments in both HCT116 and RKO cells. The profiles of reactivation of silenced genes were also different in combination of PJ-34 and 5-aza-dC and their single treatments. The results suggest that the combinational use of 5-aza-dC and PARP inhibitor may be useful by causing distinct transcriptional profile changes.

Radiosensitization to γ-Ray by Functional Inhibition of APOBEC3G.

The radiosensitization of tumor cells is one of the promising approaches for enhancing radiation damage to cancer cells and limiting radiation effects on normal tissue. In this study, we performed a comprehensive screening of radiosensitization targets in human lung cancer cell line A549 using an shRNA library and identified apolipoprotein B mRNA editing enzyme catalytic subunit 3G (APOBEC3G: A3G) as a candidate target. APOBEC3G is an innate restriction factor that inhibits HIV-1 infection as a cytidine deaminase. APOBEC3G knockdown with siRNA showed an increased radiosensitivity in several cancer cell lines, including pancreatic cancer MIAPaCa2 cells and lung cancer A549 cells. Cell cycle analysis revealed that APOBEC3G knockdown increased S-phase arrest in MIAPaCa2 and G2/M arrest in A549 cells after γ-irradiation. DNA double-strand break marker γH2AX level was increased in APOBEC3G-knocked-down MIAPaCa2 cells after γ-irradiation. Using a xenograft model of A549 in mice, enhanced radiosensitivity by a combination of X-ray irradiation and APOBEC3G knockdown was observed. These results suggest that the functional inhibition of APOBEC3G sensitizes cancer cells to radiation by attenuating the activation of the DNA repair pathway, suggesting that APOBEC3G could be useful as a target for the radiosensitization of cancer therapy.

Apical versus subclavian transcatheter aortic valve implantation: An 8-year United Kingdom analysis.

OBJECTIVES: Subclavian (SC) and transapical (TA) approaches are the main alternatives to the default femoral delivery for transcatheter aortic valve implantation (TAVI). The aim of this study was to compare complications and morbidity/mortality associated with SC and TA in a long-term time frame. METHODS: From January 2007 to July 2015, 1506 patients underwent TAVI surgery in 36 United Kingdom TAVI centers. Primary outcomes were complications according to VARC-2 criteria. The secondary outcome was long-term survival. RESULTS: The enrolled patients were distributed as follows: 1216 in the TA group and 290 in the SC group. There were no differences in the rates of acute myocardial infarction, emergency valve-in-valve, paravalvular leak, balloon post dilatation, cardiac tamponade, stroke, renal replacement therapy, vascular injuries, and 30-day mortality among the groups. Conversely, the rate of permanent pacemaker implantation (p = .02), the procedural time duration (p = .04), and the 12-month mortality (p = .03) was higher in SC than in TA, while in-hospital length of stay was reduced in SC than in TA (p = .01). Up to 8 years, the long-term mortality was not different among groups (p = .77), and no difference in long-term survival between self- versus balloon-expandable devices was found (p = .26). CONCLUSIONS: According to our results, TA provided the best 12-month survival compared to SC, while the long-term survival up to 2900 days is not significantly different between groups, so SC and TA may both represent a safe non-femoral access if femoral is precluded.

Geographical variations in left main coronary artery revascularisation: a prespecified analysis of the EXCEL trial.

BACKGROUND: The EXCEL trial reported similar five-year rates of the primary composite outcome of death, myocardial infarction (MI), or stroke after percutaneous coronary intervention (PCI) compared with coronary artery bypass grafting (CABG) for treatment of obstructive left main coronary artery disease (LMCAD). AIMS: We sought to determine whether these outcomes remained consistent regardless of geography of enrolment. METHODS: We performed a prespecified subgroup analysis based on regional enrolment. RESULTS: Among 1,905 patients randomised to PCI (n=948) or CABG (n=957), 1,075 (56.4%) were recruited at 52 European Union (EU) centres, and 752 (39.5%) were recruited at 67 North American (NA) centres. EU versus NA patients varied according to numerous baseline demographics, anatomy, pharmacotherapy and procedural characteristics. Nonetheless, the relative rates of the primary endpoint after PCI versus CABG were consistent across EU versus NA centres at 30 days and 5 years. However, NA participants had substantially higher late rates of ischaemia-driven revascularisation (IDR) after PCI, driven predominantly by the need for greater target vessel and lesion revascularisation. This culminated in a significant difference in the relative risk of the secondary composite outcome of death, MI, stroke, or IDR at 5 years (pinteraction=0.02). CONCLUSIONS: In the EXCEL trial, the relative risks for the 30-day and five-year primary composite outcome of death, MI or stroke after PCI versus CABG were consistent irrespective of geography. However, five-year rates of IDR after PCI were significantly higher in NA centres, a finding the Heart Team and patients should consider when making treatment decisions. ClinicalTrials.gov identifier: NCT01205776.

In-hospital stroke after transcatheter aortic valve implantation: A UK observational cohort analysis.

OBJECTIVES: We sought to identify baseline demographics and procedural factors that might independently predict in-hospital stroke following transcatheter aortic valve implantation (TAVI). BACKGROUND: Stroke is a recognized, albeit infrequent, complication of TAVI. Established predictors of procedure-related in-hospital stroke; however, remain poorly defined. METHODS: We conducted an observational cohort analysis of the multicenter UK TAVI registry. The primary outcome measure was the incidence of in-hospital stroke. RESULTS: A total of 8,652 TAVI procedures were performed from 2007 to 2015. There were 205 in-hospital strokes reported by participating centers equivalent to an overall stroke incidence of 2.4%. Univariate analysis showed that the implantation of balloon-expandable valves caused significantly fewer strokes (balloon-expandable 96/4,613 [2.08%] vs. self-expandable 95/3,272 [2.90%]; p = .020). After multivariable analysis, prior cerebrovascular disease (CVD) (odds ratio [OR] 1.51, 95% confidence interval [CI 1.05-2.17]; p = .03), advanced age at time of operation (OR 1.02 [0.10-1.04]; p = .05), bailout coronary stenting (OR 5.94 [2.03-17.39]; p = .008), and earlier year of procedure (OR 0.93 [0.87-1.00]; p = .04) were associated with an increased in-hospital stroke risk. There was a reduced stroke risk in those who had prior cardiac surgery (OR 0.62 [0.41-0.93]; p = .01) and a first-generation balloon-expandable valve implanted (OR 0.72 [0.53-0.97]; p = .03). In-hospital stroke significantly increased 30-day (OR 5.22 [3.49-7.81]; p < .001) and 1-year mortality (OR 3.21 [2.15-4.78]; p < .001). CONCLUSIONS: In-hospital stroke after TAVI is associated with substantially increased early and late mortality. Factors independently associated with in-hospital stroke were previous CVD, advanced age, no prior cardiac surgery, and deployment of a predominantly first-generation self-expandable transcatheter heart valve.

Long-Term Survival and Outcomes According to VARC-2 Criteria for Subclavian, Direct Aortic, Femoral, and Apical Implantation: An 8-Year United Kingdom TAVI Surgical Experience.

OBJECTIVES: The use of transcatheter aortic valve implantation (TAVI) has expanded as an alternative to aortic valve replacement, and more than 500,000 patients have been treated worldwide since April, 2002. The aim of this study was to compare complications and morbidity/mortality associated with different TAVI approaches as alternatives to a surgical-femoral approach. METHODS: From January 2007 to January 2015, 2,863 patients underwent TAVI surgery in 36 United Kingdom TAVI centers. Primary outcomes were complications according to VARC-2 criteria. The secondary outcome was long-term survival. RESULTS: The enrolled patients were distributed as follows: 1,150 in the surgical-femoral (SF) group, 1,216 in the trans-apical (TA) group, 207 in the direct-aortic (DA) group, and 290 in the subclavian (SC) group. There were no differences in the rates of acute myocardial infarction, emergency valve-in-valve, cardiac tamponade, or TIA among the groups. The rates of stroke and renal replacement therapy, as well as in-hospital stay, in-hospital death, and 30-day and 12-month mortality in DA and TA were higher than those in SC and SF. The rates of paravalvular leak and balloon post-dilatation in SC and DA were higher than those in TA and SF. The rates of vascular injuries and permanent pacemaker implantation in SC and SF were higher than those in DA and TA. SF provided the best long term-survival (p = 0.008). CONCLUSIONS: This was a large study that compared outcomes and long-term survival among different TAVI surgical approaches in a national real-world setting. According to our results, SF provided the best survival. While SC provided worse survival than SF, it was still better than TA and DA, and thus may represent the safest non-femoral access if use of the femoral approach is precluded.

Continuous intracoronary versus standard intravenous infusion of adenosine for fractional flow reserve assessment: the HYPEREMIC trial.

AIMS: The aim of this study was to evaluate the accuracy of a continuous intracoronary (IC) adenosine infusion, administered through the novel HYPEREM™IC over-the-wire microcatheter, to measure fractional flow reserve (FFR). METHODS AND RESULTS: The HYPEREMIC trial was a randomised, non-inferiority, crossover study in which patients with intermediate coronary lesions were enrolled for sequential pressure wire studies. FFR was measured using intravenous (IV) (140-180 mcg/kg/min) versus continuous non-weight-adjusted IC (360 mcg/min) adenosine. Patients were randomised and blinded to the order in which they received the adenosine, separated by a washout period. The primary endpoint was the mean hyperaemic FFR. Forty-one patients were enrolled at three UK sites between June and November 2016. The mean (standard deviation) FFR was 0.82 (±0.09) after IC versus 0.84 (±0.09) after IV adenosine. The difference of -0.02 (95% confidence interval [CI]: -0.03 to -0.01) confirmed the non-inferiority (margin <0.05) of IC to IV adenosine. Intracoronary adenosine was associated with a shorter mean time to maximal hyperaemia (difference -44 [95% CI: -59 to -29] seconds; p<0.0001). Chest discomfort was reported in 32/41 (78.0%) patients during IV adenosine versus 12/41 (29.3%) patients during IC adenosine. CONCLUSIONS: Continuous IC adenosine was a reliable, faster and better tolerated method of achieving maximal hyperaemia compared to IV adenosine.

Nuclear import of transcriptional corepressor BCOR occurs through interaction with karyopherin α expressed in human periodontal ligament.

Mutations in the gene encoding BCL-6 corepressor (BCOR) are responsible for oculofaciocardiodental (OFCD) syndrome, which is a rare X-linked dominant disorder characterized by radiculomegaly of permanent teeth as the most typical symptom. To function as a transcriptional corepressor, BCOR needs to enter the nucleus; however, the molecular pathway for its nuclear translocation during dental root formation remains unclear. The purpose of this study was to determine the mechanism underlying BCOR transport into the nucleus. Our results showed that human periodontal ligament (PDL) cells expressed karyopherin α (KPNA)2, KPNA4, and KPNA6 belonging to a family of nuclear import proteins, which interacted with BCOR in the immunoprecipitation assay. Site-directed mutagenesis targeting the two nuclear localization signals (NLSs) within BCOR reduced its nuclear translocation; however, co-expression of KPNA2, KPNA4, or KPNA6 with BCOR carrying a previously described mutation which eliminated one of the two NLSs significantly increased nuclear accumulation of the mutant BCOR, indicating participation of KPNA in BCOR nuclear translocation. Comparative expression profiling of PDL cells isolated from normal and OFCD patients revealed significant downregulation of SMAD4, GLI1, and nuclear factor 1-C (NFIC) mRNA expression, suggesting that BCOR mutations cause hyperactive root formation in OFCD syndrome by inhibiting SMAD4-Hedgehog-NFIC signaling implicated in dental root development. Our study contributes to understanding of the mechanisms providing nuclear import of BCOR during root formation.

Selection of P2Y12 Inhibitor in Percutaneous Coronary Intervention and/or Acute Coronary Syndrome.

The P2Y12 receptor plays a critical role in the amplification of platelet aggregation in response to various agonists and stable thrombus generation at the site of vascular injury leading to deleterious ischemic complications. Therefore, treatment with a P2Y12 receptor blocker is a major effective strategy to prevent ischemic complications in high-risk patients with acute coronary syndrome (ACS) and patients undergoing percutaneous coronary intervention (PCI). The determination of optimal platelet inhibition is based on maximizing antithrombotic properties while minimizing bleeding risk and is critically dependent on individual patient's propensity for thrombotic and bleeding risks. Immediately after ACS and during PCI, where highly elevated thrombotic activity is present, a loading dose administration with a potent P2Y12 receptor blocker such as ticagrelor or prasugrel is preferred. In stable coronary artery disease patients undergoing PCI, clopidogrel is widely used. In addition, in patients with ST-segment elevation myocardial infraction who cannot take oral medications, a fast acting intravenous glycoprotein IIb/IIIa inhibitor or P2Y12 receptor blocker, cangrelor, may add clinical benefits. During long term therapy, a strategy that prevents ischemic risk while avoiding excessive bleeding risk is similarly desired. Although up to one year dual antiplatelet therapy (DAPT) is recommended in patients undergoing elective stenting, the available data support the anti-ischemic benefit of prolonged DAPT (more than1 year) in patients with prior MI. In addition to the DAPT risk calculator tool, future risk assessment methods that analyze intrinsic thrombogenicity and atherosclerotic coronary burden may further identify the optimal candidate for prolonged DAPT to improve net clinical outcomes.

Current controversies in the use of aspirin and ticagrelor for the treatment of thrombotic events.

INTRODUCTION: A P2Y12 inhibitor plus aspirin is the most widely used antiplatelet strategy to prevent adverse outcomes in the setting of atherothrombotic vascular disease. Areas covered: A paucity of robust evidence for an optimal dose, gastrointestinal toxicity, ineffectiveness in high-risk patients and interactions with other antiplatelet agents, are major controversies associated with aspirin therapy. Ticagrelor is a reversibly binding oral P2Y12 receptor blocker that mediates potent inhibition of adenosine diphosphate-induced platelet function. It is more effective than clopidogrel in preventing thrombotic events in acute coronary syndrome patients. The absence of a beneficial effect for ticagrelor versus clopidogrel in ACS observed in the North American subgroup of the PLATelet inhibition and patient Outcomes (PLATO) trial has been attributed to a higher concomitant aspirin dose. Expert commentary: Ongoing studies are now investigating the plausibility of removing aspirin therapy in the setting of potent P2Y12 receptor blockade via ticagrelor monotherapy or replacing aspirin with an oral anticoagulant.

What is the optimum adjunctive reperfusion strategy for primary percutaneous coronary intervention?

Acute ST-segment elevation myocardial infarction (STEMI) is a dynamic, thrombus-driven event. As understanding of its pathophysiology has improved, the central role of platelets in initiation and orchestration of this process has become clear. Key components of STEMI include formation of occlusive thrombus, mediation and ultimately amplification of the local vascular inflammatory response resulting in increased vasoreactivity, oedema formation, and microvascular obstruction. Activation, degranulation, and aggregation of platelets are the platforms from which these components develop. Therefore, prompt, potent, and predictable antithrombotic therapy is needed to optimise clinical outcomes after primary percutaneous coronary intervention. We review present pharmacological and mechanical adjunctive therapies for reperfusion and ask what is the optimum combination when primary percutaneous coronary intervention is used as the mode of revascularisation in patients with STEMI.

Percutaneous mechanical thrombectomy for the treatment of acute massive pulmonary embolism: case report.

BACKGROUND: To our knowledge we report the first case of percutaneous mechanical thrombectomy used for the treatment of massive pulmonary embolism in the United Kingdom. Pulmonary embolism is a common disease process but can be difficult to diagnose. Massive pulmonary embolism presenting with profound hypotension, however, is rare. Both phenomena carry with them significant mortality. Traditionally those patients suffering haemodynamic compromise from pulmonary embolism are treated with intravenous or catheter-directed thrombolysis. When this is contraindicated surgical embolectomy or mechanical techniques via a right heart catheter are alternative options. The former is well established but the latter is less commonly utilised in clinical practice. Our aim is to highlight the effectiveness and relative safety of percutaneous mechanical thrombectomy as a therapeutic tool in massive pulmonary embolism. CASE PRESENTATION: A 70 year-old gentleman presented with a 4-month history of dry cough and general malaise. Clinical examination along with routine chest radiograph confirmed a left pleural effusion which was drained. Computed tomography of the chest, abdomen and pelvis revealed a left renal mass consistent with renal cell carcinoma plus multiple metastatic subpleural nodules. Following planned thoracoscopy and pleural biopsy the patient became acutely dyspnoeic and hypotensive. Relevant investigations including computed tomography pulmonary angiogram confirmed a large saddle embolus extending in to the lobar branches of both left and right pulmonary arteries. There were several relative contraindications to thrombolysis and so the patient proceeded to have percutaneous mechanical thrombectomy with excellent results. The patient made a full recovery from the acute episode and was discharged home on warfarin with a view to planned cyto-reductive nephrectomy. CONCLUSION: We illustrate here that percutaneous mechanical thrombectomy can be a safe and effective method of treating massive pulmonary embolism when thrombolysis is relatively contraindicated. It may also be of use as an adjuvant therapy in those patients able to receive thrombolysis. In the future further evaluation involving a larger cohort of subjects is necessary to determine whether this treatment is superior to surgical embolectomy when thrombolysis cannot be performed.