USP24-i-101 targeting of USP24 activates autophagy to inhibit drug resistance acquired during cancer therapy.

Drug resistance in cancer therapy is the major reason for poor prognosis. Addressing this clinically unmet issue is important and urgent. In this study, we found that targeting USP24 by the specific USP24 inhibitors, USP24-i and its analogues, dramatically activated autophagy in the interphase and mitotic periods of lung cancer cells by inhibiting E2F4 and TRAF6, respectively. USP24 functional knockout, USP24C1695A, or targeting USP24 by USP24-i-101 inhibited drug resistance and activated autophagy in gefitinib-induced drug-resistant mice with doxycycline-induced EGFRL858R lung cancer, but this effect was abolished after inhibition of autophagy, indicating that targeting USP24-mediated induction of autophagy is required for inhibition of drug resistance. Genomic instability and PD-L1 levels were increased in drug resistant lung cancer cells and were inhibited by USP24-i-101 treatment or knockdown of USP24. In addition, inhibition of autophagy by bafilomycin-A1 significantly abolished the effect of USP24-i-101 on maintaining genomic integrity, decreasing PD-L1 and inhibiting drug resistance acquired in chemotherapy or targeted therapy. In summary, an increase in the expression of USP24 in cancer cells is beneficial for the induction of drug resistance and targeting USP24 by USP24-i-101 optimized from USP24-i inhibits drug resistance acquired during cancer therapy by increasing PD-L1 protein degradation and genomic stability in an autophagy induction-dependent manner.

Tp53 haploinsufficiency is involved in hotspot mutations and cytoskeletal remodeling in gefitinib-induced drug-resistant EGFRL858R-lung cancer mice.

Tumor heterogeneity is the major factor for inducing drug resistance. p53 is the major defender to maintain genomic stability, which is a high proportion mutated in most of the cancer types. In this study, we established in vivo animal models of gefitinib-induced drug-resistant lung cancer containing EGFRL858R and EGFRL858R*Tp53+/- mice to explore the molecular mechanisms of drug resistance by studying the genomic integrity and global gene expression. The cellular morphology of the lung tumors between gefitinib-induced drug-resistant mice and drug-sensitive mice were very different. In addition, in drug-resistant mice, the expression of many cytoskeleton-related genes were changed, accompanied by decreased amounts of actin filaments and increased amounts of microtubule, indicating that significant cytoskeletal remodeling is induced in gefitinib-induced drug-resistant EGFRL858R and EGFRL858R*Tp53+/- lung cancer mice. The gene expression profiles and involved pathways were different in gefitinib-sensitive, gefitinib-resistant and Tp53+/--mice. Increases in drug resistance and nuclear size (N/C ratio) were found in EGFRL858R*Tp53+/- drug-resistant mice. Mutational hotspot regions for drug resistance via Tp53+/+- and Tp53+/--mediated pathways are located on chromosome 1 and chromosome 11, respectively, and are related to prognosis of lung cancer cohorts. This study not only builds up a gefitinib-induced drug-resistant EGFRL858R lung cancer animal model, but also provides a novel mutation profile in a Tp53+/+- or Tp53+/--mediated manner and induced cytoskeleton remodeling during drug resistance, which could contribute to the prevention of drug resistance during cancer therapy.

Impact and Modifiers of Ventricular Pacing in Patients With Single Ventricle Circulation.

BACKGROUND: Palliation of the single ventricle (SV) circulation is associated with a burden of lifelong complications. Previous studies have identified that the need for a permanent ventricular pacing system (PPMv) may be associated with additional adverse long-term outcomes. OBJECTIVES: The goal of this study was to quantify the attributable risk of PPMv in patients with SV, and to identify modifiable risk factors. METHODS: This international study was sponsored by the Pediatric and Congenital Electrophysiology Society. Centers contributed baseline and longitudinal data for functionally SV patients with PPMv. Enrollment was at implantation. Controls were matched 1:1 to PPMv subjects by ventricular morphology and sex, identified within center, and enrolled at matched age. Primary outcome was transplantation or death. RESULTS: In total, 236 PPMv subjects and 213 matched controls were identified (22 centers, 9 countries). Median age at enrollment was 5.3 years (quartiles: 1.5-13.2 years), follow-up 6.9 years (3.4-11.6 years). Median percent ventricular pacing (Vp) was 90.8% (25th-75th percentile: 4.3%-100%) in the PPMv cohort. Across 213 matched pairs, multivariable HR for death/transplant associated with PPMv was 3.8 (95% CI 1.9-7.6; P < 0.001). Within the PPMv population, higher Vp (HR: 1.009 per %; P = 0.009), higher QRS z-score (HR: 1.19; P = 0.009) and nonapical lead position (HR: 2.17; P = 0.042) were all associated with death/transplantation. CONCLUSIONS: PPMv in patients with SV is associated with increased risk of heart transplantation and death, despite controlling for increased associated morbidity of the PPMv cohort. Increased Vp, higher QRS z-score, and nonapical ventricular lead position are all associated with higher risk of adverse outcome and may be modifiable risk factors.

Estradiol-mediated inhibition of DNMT1 decreases p53 expression to induce M2-macrophage polarization in lung cancer progression.

Previous studies indicate that estrogen positively regulates lung cancer progression. Understanding the reasons will be beneficial for treating women with lung cancer in the future. In this study, we found that tumor formation was more significant in female EGFRL858R mice than in male mice. P53 expression levels were downregulated in the estradiol (E2)-treated lung cancer cells, female mice with EGFRL858R-induced lung cancer mice, and premenopausal women with lung cancer. E2 increased DNA methyltransferase 1 (DNMT1) expression to enhance methylation in the TP53 promoter, which led to the downregulation of p53. Overexpression of GFP-p53 decreased DNMT1 expression in lung cancer cells. TP53 knockout in mice with EGFRL858R-induced lung cancer not only changed gene expression in cancer cells but also increased the polarization of M2 macrophages by increasing C-C motif chemokine ligand 5 (CCL5) expression and decreasing growth differentiation factor 15 (GDF15) expression. The TP53 mutation rate was increased in females with late-stage but not early-stage lung cancer compared to males with lung cancer. In conclusion, E2-induced DNMT1 and p53 expression were negatively regulated each other in females with lung cancer, which not only affected cancer cells but also modulated the tumor-associated microenvironment, ultimately leading to a poor prognosis.

Estradiol-mediated inhibition of Sp1 decreases miR-3194-5p expression to enhance CD44 expression during lung cancer progression.

BACKGROUND: Sp1, an important transcription factor, is involved in the progression of various cancers. Our previous studies have indicated that Sp1 levels are increased in the early stage of lung cancer progression but decrease during the late stage, leading to poor prognosis. In addition, estrogen has been shown to be involved in lung cancer progression. According to previous studies, Sp1 can interact with the estrogen receptor (ER) to coregulate gene expression. The role of interaction between Sp1 and ER in lung cancer progression is still unknown and will be clarified in this study. METHODS: The clinical relevance between Sp1 levels and survival rates in young women with lung cancer was studied by immunohistochemistry. We validated the sex dependence of lung cancer progression in EGFRL858R-induced lung cancer mice. Wound healing assays, chamber assays and sphere formation assays in A549 cells, Taxol-induced drug-resistant A549 (A549-T24) and estradiol (E2)-treated A549 (E2-A549) cells were performed to investigate the roles of Taxol and E2 in lung cancer progression. Luciferase reporter assays, immunoblot and q-PCR were performed to evaluate the interaction between Sp1, microRNAs and CD44. Tail vein-injected xenograft experiments were performed to study lung metastasis. Samples obtained from lung cancer patients were used to study the mRNA level of CD44 by q-PCR and the protein levels of Sp1 and CD44 by immunoblot and immunohistochemistry. RESULTS: In this study, we found that Sp1 expression was decreased in premenopausal women with late-stage lung cancer, resulting in a poor prognosis. Tumor formation was more substantial in female EGFRL858R mice than in male mice and ovariectomized female mice, indicating that E2 might be involved in the poor prognosis of lung cancer. We herein report that Sp1 negatively regulates metastasis and cancer stemness in E2-A549 and A549-T24 cells. Furthermore, E2 increases the mRNA and protein levels of RING finger protein 4 (RNF4), which is the E3-ligase of Sp1, and thereby decreases Sp1 levels by promoting Sp1 degradation. Sp1 can be recruited to the promoter of miR-3194-5p, and positively regulate its expression. Furthermore, there was a strong inverse correlation between Sp1 and CD44 levels in clinical lung cancer specimens. Sp1 inhibited CD44 expression by increasing the expression of miR-3194-5p, miR-218-5p, miR-193-5p, miR-182-5p and miR-135-5p, ultimately resulting in lung cancer malignancy. CONCLUSION: Premenopausal women with lung cancer and decreased Sp1 levels have a poor prognosis. E2 increases RNF4 expression to repress Sp1 levels in premenopausal women with lung cancer, thus decreasing the expression of several miRNAs that can target CD44 and ultimately leading to cancer malignancy.

USP24 promotes drug resistance during cancer therapy.

Drug resistance has remained an important issue in the treatment and prevention of various diseases, including cancer. Herein, we found that USP24 not only repressed DNA-damage repair (DDR) activity by decreasing Rad51 expression to cause the tumor genomic instability and cancer stemness, but also increased the levels of the ATP-binding cassette (ABC) transporters P-gp, ABCG2, and ezrin to enhance the pumping out of Taxol from cancer cells, thus resulted in drug resistance during cancer therapy. A novel USP24 inhibitor, NCI677397, was screened for specific inhibiting the catalytic activity of USP24. This inhibitor was identified to suppress drug resistance via decreasing genomic instability, cancer stemness, and the pumping out of drugs from cancer cells. Understanding the role and molecular mechanisms of USP24 in drug resistance will be beneficial for the future development of a novel USP24 inhibitor. Our studies provide a new insight of USP24 inhibitor for clinically implication of blocking drug resistance during chemotherapy.

USP24 stabilizes bromodomain containing proteins to promote lung cancer malignancy.

Bromodomain (BRD)-containing proteins are important for chromatin remodeling to regulate gene expression. In this study, we found that the deubiquitinase USP24 interacted with BRD through its C-terminus increased the levels of most BRD-containing proteins through increasing their protein stability by the removal of ubiquitin from Lys391/Lys400 of the BRD. In addition, we found that USP24 and BRG1 could regulate each other through regulating the protein stability and the transcriptional activity, respectively, of the other, suggesting that the levels of USP24 and BRG1 are regulated to form a positive feedback loop in cancer progression. Loss of the interaction motif of USP24 eliminated the ability of USP24 to stabilize BRD-containing proteins and abolished the effect of USP24 on cancer progression, including its inhibition of cancer cell proliferation and promotion of cancer cell migration, suggesting that the interaction between USP24 and the BRD is important for USP24-mediated effects on cancer progression. The targeting of BRD-containing proteins has been developed as a strategy for cancer therapy. Based on our study, targeting USP24 to inhibit the levels of BRD-containing proteins may inhibit cancer progression.

External Cardioversion-Defibrillation with Pushing Down on the Chest Wall to Increase the Success Rate in Obese Patients.

BACKGROUND The energy delivered by a defibrillator is expressed in joules (J). However, current is what actually defibrillates the heart and is related to the voltage-to-impedance ratio. With the same energy, the lower the transthoracic impedance, the higher the current delivered. In obese patients, pushing the chest wall toward the heart during electric shock can result in an improved outcome. CASE REPORT We report the cases of 3 obese patients with previously failed cardioversion/defibrillation who had an eventual shock success. (1) A 17-year-old girl failed multiple defibrillation efforts for her recurrent ventricular fibrillation. After ECMO, with the physician pushing down the chest wall, a 200-J defibrillation converted her VF. (2) A 63-year-old man with recurrent atrial fibrillation (AF) had an unsuccessful 150-J shock followed by a successful 200-J cardioversion. His AF recurred. After amiodarone bolus, a 200-J shock converted it to sinus. Another recurrent AF failed 150-J cardioversion. With chest pushing down, a 150-J cardioversion was successful. (3) A 65-year-old man underwent elective cardioversion for AF. A 200-J shock was unsuccessful. A 200-J shock with pressure on the chest successfully converted it. CONCLUSIONS We performed successful electrical cardioversion/defibrillation with this "pushing down the chest while shocking" method. Many clinicians are still unaware of this method, especially in obese patients. With the increasing prevalence of obesity, it is urgent to perform a randomized study to confirm the efficacy and safety of this method, and integrate it into advanced cardiac life support protocols.

Genotype Predicts Outcomes in Fetuses and Neonates With Severe Congenital Long QT Syndrome.

OBJECTIVES: This study sought to determine the relationship between long QT syndrome (LQTS) subtype (LTQ1, LTQ2, LTQ3) and postnatal cardiac events (CEs). BACKGROUND: LQTS presenting with 2:1 atrioventricular block or torsades de pointes in the fetus and/or neonate has been associated with risk for major CEs, but overall outcomes and predictors remain unknown. METHODS: A retrospective study involving 25 international centers evaluated the course of fetuses/newborns diagnosed with congenital LQTS and either 2:1 atrioventricular block or torsades de pointes. The primary outcomes were age at first CE after dismissal from the newborn hospitalization and death and/or cardiac transplantation during follow-up. CE was defined as aborted cardiac arrest, appropriate shock from implantable cardioverter-defibrillator, or sudden cardiac death. RESULTS: A total of 84 fetuses and/or neonates were identified with LQTS (12 as LQT1, 35 as LQT2, 37 as LQT3). Median gestational age at delivery was 37 weeks (interquartile range: 35 to 39 weeks) and age at hospital discharge was 3 weeks (interquartile range: 2 to 5 weeks). Fetal demise occurred in 2 and pre-discharge death in 1. Over a median of 5.2 years, there were 1 LQT1, 3 LQT2, and 23 LQT3 CEs (13 aborted cardiac arrests, 5 sudden cardiac deaths, and 9 appropriate shocks). One patient with LQT1 and 11 patients with LQT3 died or received cardiac transplant during follow-up. The only multivariate predictor of post-discharge CEs was LQT3 status (LQT3 vs. LQT2: hazard ratio: 8.4; 95% confidence interval: 2.6 to 38.9; p < 0.001), and LQT3, relative to LQT2, genotype predicted death and/or cardiac transplant (p < 0.001). CONCLUSIONS: In this large multicenter study, fetuses and/or neonates with LQT3 but not those with LQT1 or LQT2 presenting with severe arrhythmias were at high risk of not only frequent, but lethal CEs.

Using coronary sinus ostium as the reference for the slow pathway ablation of atrioventricular nodal reentrant tachycardia in children.

BACKGROUND: Successful slow pathway (SP) ablation sites for atrioventricular nodal reentrant tachycardia (AVNRT) are usually located inside the Koch's triangle (KT). This study aimed to determine the ablation site of SP using the coronary sinus (CS) ostium (CSO) as the reference and to evaluate the efficacy of the CSO-guided SP ablation. METHODS: A regional geometry around the KT was constructed by 3D mapping in 52 consecutive patients under age 18 with AVNRT. SP cryoablation was performed. If initial cryoablation was unsuccessful or cryoablation was deemed not suitable, then radiofrequency (RF) ablation was performed. The successful ablation site direction relative to the CSO was expressed as o'clock with the CSO viewed as a clock. RESULTS: Cryoablation was used as the primary energy source in 40 patients. Of which, 32 were successful and eight required additional RF ablation. Direct RF ablation was performed in 11 patients. Using the CSO as reference, the successful site with cryoablation was at its 2.2 ± 0.6 o'clock; the RF ablation success site was at CSO 2.7 ± 0.5 o'clock (P = .006). During a median follow-up of 12 month, there was 98% success of SP ablation in these patients, with one patient with RF ablation had a tachycardia recurrence. CONCLUSIONS: Using CSO as reference, the cryoablation site at its 2:00 o'clock and RF ablation at its 3:00 o'clock are highly efficacious for SP ablation with good short-term outcomes, and may be a useful tool in guiding the ablation target for AVNRT.

Possible Propofol-Induced Priapism Following Cardiac Catheter Ablation in a Teenager.

BACKGROUND Priapism is rarely reported as a potential complication after the cardiac ablation procedure. We report the case of a teenager admitted for atrial flutter ablation who developed priapism following the procedure. CASE REPORT A 16-year-old male with episodic atrial flutter came to our hospital for an electrophysiological study and catheter ablation. During the procedure, he was given IV propofol for anesthesia and IV heparin for anticoagulation. After the procedure, nursing noted that he had an erection, which persisted for 5 h, with complaints of discomfort. There was no known history of sickle cell disease or trauma to the perineum, nor did he endorse any prior prolonged erections. On physical examination, he had a circumcised phallus with rigid and non-tender corpora cavernosa. He was given 5 mg terbutaline PO, without improvement. Three hours later, a second dose of terbutaline was given. In addition, a penis corporal venous blood gas was taken, and the result was consistent with an ischemic priapism. He had detumescence 1-2 min later. The total duration of his priapism was 8 h. There was no swelling, pain, or any sequelae after detumescence. CONCLUSIONS Although priapism rarely occurs as a complication following catheter ablation procedures due to propofol use, prolonged priapism can result in corporal fibrosis and cause future erectile dysfunction. Recognition and treatment of priapism in the postoperative period may be delayed due to a patient's hesitance to express concerns. To prevent future erectile dysfunction, signs of priapism should be included in routine postoperative evaluation in male patients.

Asymptomatic Idiopathic Belhassen Ventricular Tachycardia in a Neonate Detected Using 'Smart Sock' Wearable Smartphone-Enabled Cardiac Monitoring.

BACKGROUND Wearable smartphone-enabled cardiac monitoring devices can aid the diagnosis of asymptomatic tachycardia in neonates and infants. This report is of a rare case of left posterior fascicular ventricular tachycardia of Belhassen type detected in a neonate by 'smart sock' cardiac monitoring. CASE REPORT A premature baby boy at 37 weeks gestational age was discharged home after three days without complication, and was given 'smart socks' to wear. He was followed up daily for the management of hyperbilirubinemia, which was treated in the outpatient clinic with a phototherapy blanket. He was admitted to the emergency room (ER) at 6 days of age because his 'smart socks' identified a tachycardia of between 180-200 bpm. His parents reported no fever, cough, nasal congestion, or emesis. On examination in the ER, he was alert with no distress. An electrocardiogram (ECG) showed a sustained monomorphic and wide QRS tachycardia with a heart rate of 200 bpm, right bundle branch block (RBBB), and a superior axis that was compatible with a diagnosis of left posterior fascicular ventricular tachycardia of Belhassen type. The echocardiogram showed a structurally normal heart with normal cardiac function. His tachycardia spontaneously converted to normal sinus rhythm after four hours. He was discharged home three days later without further episodes of tachycardia. Cardiac monitoring using 'smart socks' continued at home, and no further arrhythmias were detected at one year of age. CONCLUSIONS The home use of smartphone-enabled technology to monitor the neonatal and infant cardiac heart rate can identify asymptomatic arrhythmias.

The role of ubiquitin-specific peptidases in cancer progression.

Protein ubiquitination is an important mechanism for regulating the activity and levels of proteins under physiological conditions. Loss of regulation by protein ubiquitination leads to various diseases, such as cancer. Two types of enzymes, namely, E1/E2/E3 ligases and deubiquitinases, are responsible for controlling protein ubiquitination. The ubiquitin-specific peptidases (USPs) are the main members of the deubiquitinase family. Many studies have addressed the roles of USPs in various diseases. An increasing number of studies have indicated that USPs are critical for cancer progression, and some USPs have been used as targets to develop inhibitors for cancer prevention. Herein we collect and organize most of the recent studies on the roles of USPs in cancer progression and discuss the development of USP inhibitors for cancer therapy in the future.

Relation Between New York Heart Association Functional Class and Objective Measures of Cardiopulmonary Exercise in Adults With Congenital Heart Disease.

We aimed to compare New York Heart Association (NYHA) functional class in adult congenital heart disease (ACHD) patients with objectively measured cardiopulmonary exercise testing (CPET) parameters. This study included retrospective review of ACHD patients who underwent a CPET between August 2014 and April 2018 at our center. Patients were grouped according to severity of CHD, and NYHA class as recorded in their medical record or estimated from the clinical narrative. A total of 175 ACHD patients (mean age 30 ± 11 years) with NYHA class I-III enrolled in the study. The NYHA functional class was II or III in most complex CHD. There was a strong inverse relation between NYHA class and peak oxygen consumption, oxygen uptake efficiency slope, and the double product at peak exercise (product of heart rate and systolic blood pressure) (p<0.0001). There was no relation between NYHA class and ventilation efficiency slope (p = 0.37). In conclusion, NYHA functional class correlates with objective measures of CPET, however there is wide variability in measured exercise capacity in each NYHA classification. Therefore, whereas NYHA class of patients is a simple measure for assessment of functional status, CPET is an important tool to identify the source of exercise limitation in ACHD patients.

Senning Procedure for Physiological Atrial Inversion With Left Atrial Isomerism.

We present the case of an infant with left atrial isomerism with complex pulmonary and systemic venous connections that resulted in physiological parallel circulation in the setting of ventriculoarterial concordance who was surgically treated using the Senning procedure. This case highlights a rare cause for cyanosis due to poor mixing from a parallel circulation and an issue with nomenclature. (Level of Difficulty: Advanced.).

What have we learned in the last 20 years? A comparison of a modern era pediatric and congenital catheter ablation registry to previous pediatric ablation registries.

BACKGROUND: Since the onset of pediatric catheter ablation, the pediatric electrophysiology community has reported outcomes via various registries (PAPCA [Prospective Assessment After Pediatric Cardiac Ablation], PCAR [Pediatric Catheter Ablation Registry]). Most recently, a modern era pediatric and congenital ablation registry (MAP-IT [Multicenter Pediatric and Congenital EP Quality Initiative]) was developed for eventual incorporation into the National Cardiovascular Data Registry (NCDR) IMPACT (Improving Pediatric and Adult Congenital Treatment) registry. OBJECTIVE: The purpose of this study was to describe initial findings from the MAP-IT pilot registry and to compare these findings to earlier registries. METHODS: Before entering the NCDR IMPACT registry, MAP-IT was active at 12 centers (11 in the United States) between October 2014 and April 2016. All electrophysiological studies for patients younger than 21 years and for patients of all ages with structural congenital heart disease were included. We compared the acute success, fluoroscopy and procedural times, and frequency of complications between MAP-IT and the earlier registries. RESULTS: Acute success rates have improved from the initial PCAR registry for both accessory and slow pathway substrates. Both fluoroscopy and procedural times have significantly decreased across the time periods (fluoroscopy time 47.6 ± 40 minutes to 7.0 ± 9.2 minutes; P <.001; procedural time 257 ± 157 minutes to 166 ± 84 minutes; P <.001). CONCLUSION: Acute success rates and fluoroscopy and procedural times in pediatric ablation all have improved over the last 25 years.

USP24 induces IL-6 in tumor-associated microenvironment by stabilizing p300 and ß-TrCP and promotes cancer malignancy.

We have previously demonstrated that USP24 is involved in cancer progression. Here, we found that USP24 expression is upregulated in M2 macrophages and lung cancer cells. Conditioned medium from USP24-knockdown M2 macrophages decreases the migratory and chemotactic activity of lung cancer cells and the angiogenic properties of human microvascular endothelial cell 1 (HMEC-1). IL-6 expression is significantly decreased in USP24-knockdown M2 macrophages and lung cancer cells, and IL-6-replenished conditioned medium restores the migratory, chemotactic and angiogenetic properties of the cells. USP24 stabilizes p300 and ß-TrCP to increase the levels of histone-3 acetylation and NF-κB, and decreases the levels of DNMT1 and IκB, thereby increasing IL-6 transcription in M2 macrophages and lung cancer cells, results in cancer malignancy finally. IL-6 has previously been a target for cancer drug development. Here, we provide direct evidence to support that USP24 promotes IL-6 expression, which might be beneficial for cancer therapy.

Left atrial appendage as a vantage point for mapping and ablating premature ventricular contractions originating in the epicardial left ventricular summit.

Idiopathic ventricular tachycardia arising from the LV summit epicardial area can be successfully mapped and possibly ablated from the left atrial appendage.