Multidrug resistance (MDR) is the dominant challenge in the failure of chemotherapy in cancers. Phosphatidylinositol 3-kinase (PI3K) is a lipid kinase that spreads intracellular signal cascades and regulates a variety of cellular processes. PI3Ks are considered significant causes of chemoresistance in cancer therapy. Protein kinase B (AKT) is also a significant downstream effecter of PI3K signaling, and it modulates several pathways, including inhibition of apoptosis, stimulation of cell growth, and modulation of cellular metabolism. This review highlights the aberrant activation of PI3K/AKT as a key link that modulates MDR. We summarize the regulation of numerous major targets correlated with the PI3K/AKT pathway, which is further related to MDR, including the expression of apoptosis-related protein, ABC transport and glycogen synthase kinase-3 beta (GSK-3β), synergism with nuclear factor kappa beta (NF-κB) and mammalian target of rapamycin (mTOR), and the regulation of glycolysis.

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PI3K/AKT pathway as a key link modulates the multidrug resistance of cancers

Diabetic cardiomyopathy (DCM) is a chronic complication of diabetes mellitus, characterized by abnormalities of myocardial structure and function. Researches on the models of type 1 and type 2 diabetes mellitus as well as the application of genetic engineering technology help in understanding the molecular mechanism of DCM. DCM has multiple hallmarks, including hyperglycemia, insulin resistance, increased free radical production, lipid peroxidation, mitochondrial dysfunction, endothelial dysfunction, and cell death. Essentially, cell death is considered to be the terminal pathway of cardiomyocytes during DCM. Morphologically, cell death can be classified into four different forms: apoptosis, autophagy, necrosis, and entosis. Apoptosis, as type I cell death, is the fastest form of cell death and mainly occurs depending on the caspase proteolytic cascade. Autophagy, as type II cell death, is a degradation process to remove damaged proteins, dysfunctional organelles and commences by the formation of autophagosome. Necrosis is type III cell death, which contains a great diversity of cell death processes, such as necroptosis and pyroptosis. Entosis is type IV cell death, displaying "cell-in-cell" cytological features and requires the engulfing cells to execute. There are also some other types of cell death such as ferroptosis, parthanatos, netotic cell death, lysosomal dependent cell death, alkaliptosis or oxeiptosis, which are possibly involved in DCM. Drugs or compounds targeting the signals involved in cell death have been used in clinics or experiments to treat DCM. This review briefly summarizes the mechanisms and implications of cell death in DCM, which is beneficial to improve the understanding of cell death in DCM and may propose novel and ideal strategies in future.

Distinct Types of Cell Death and the Implication in Diabetic Cardiomyopathy.

Therapeutic potential of targeting oxidative stress in diabetic cardiomyopathy

Objectives: Recent studies revealed an immuno-modulatory property of the vagus nerve referred to as the cholinergic anti-inflammatory pathway. Chemical stimulation of the efferent arm of the vagus ...

Abstract 15836: The Role of the Cholinergic Antiinflammatory Pathway in Murine Autoimmune Myocarditis

Diabetic nephropathy (DN) as a global health concern is closely related to inflammation and oxidation. Isoliquiritigenin (ISL), a natural flavonoid compound, has been demonstrated to inhibit inflammation in macrophages. Herein, we investigated the effect of ISL in protecting against the injury in STZ-induced type 1 DN and in high glucose-induced NRK-52E cells. In this study, it was revealed that the administration of ISL not only ameliorated renal fibrosis and apoptosis, but also induced the deterioration of renal function in diabetic mice. Mediated by MAPKs and Nrf-2 signaling pathways, respectively, upstream inflammatory response and oxidative stress were neutralized by ISL in vitro and in vivo. Moreover, as further revealed by the results of molecular docking, sirtuin 1 (SIRT1) binds to ISL directly, and the involvement of SIRT1 in ISL-mediated renoprotective effects was confirmed by studies using in vitro models of SIRT1 overexpression and knockdown. In summary, by reducing inflammation and oxidative stress, ISL has a significant pharmacological effect on the deterioration of DN. The benefits of ISL are associated with the direct binding to SIRT1, the inhibition of MAPK activation, and the induction of Nrf-2 signaling, suggesting the potential of ISL for DN treatment.

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Isoliquiritigenin prevents hyperglycemia-induced renal injuries by inhibiting inflammation and oxidative stress via SIRT1-dependent mechanism.

Piceatannol alleviates inflammation and oxidative stress via modulation of the Nrf2/HO-1 and NF-κB pathways in diabetic cardiomyopathy.

Background. Cardiomyocyte apoptosis is critical for the development of coxsackievirus B3- (CVB3-) induced myocarditis, which is a common cardiac disease that may result in heart failure or even sudden death. Previous studies have associated CVB3-induced apoptosis with the downregulation of antiapoptotic proteins. Here, attempts were made to examine whether nicotinic acetylcholine receptors (nAChRs), especially α3β4-nAChRs, were a novel therapeutic antiapoptotic target via the activation of survivin, a strong antiapoptotic protein, in viral myocarditis (VMC). Methods and Results. In the present study, we demonstrated that nAChRs, α3β4-nAChR subunits in particular, were present and upregulated in CVB3-infected neonatal rat cardiomyocytes (NRC) and H9c2 cells by RT-qPCR. The function of α3β4-nAChRs was next examined using its specific blocker α-CTX AuIB in vitro. The results of the TUNEL assay and western blot experiments showed that the block of α3β4-nAChRs abrogated nicotine-mediated protection of NRC from CVB3-induced apoptosis, and this effect displayed a substantial correlation with the protein expressions of pAkt, survivin, and Cleaved Caspase-3. Hence, the involvement of the PI3K/Akt pathway was further verified by LY294002, a selective inhibitor of PI3K. As a result, nicotine-mediated induction of pAkt and survivin was abolished by LY294002; meanwhile, apoptotic NRC were increased accompanied by an increase of Cleaved Caspase-3 expression. Regarding CVB3-infected BALB/c mice, the α-CTX AuIB- and LY294002-treated groups had a lower survival rate, deteriorative ventricular systolic function, and more severe inflammation than the nicotine-treated group and the modulation of pAkt, survivin, and Cleaved Caspase-3 protein expressions was similar to that in CVB3-infected NRC. In addition, we found that a nicotinic agonist reduced CVB3 replication in a dose-dependent manner in vitro, which indicates that nAChR activation may serve as a possible protection mechanism of CVB3-induced myocarditis. Conclusions. Our study demonstrated that α3β4-nAChR subunits are essential in the nicotine-mediated antiapoptotic effect of protecting cardiomyocytes from CVB3-induced apoptosis in vivo and in vitro. This protection correlated with the PI3K/Akt pathway and the inducement of the antiapoptotic protein survivin. A combination of these mechanisms serves as a novel protective response to treat viral myocarditis.

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Nicotinic Agonist Inhibits Cardiomyocyte Apoptosis in CVB3-Induced Myocarditis via α3β4-nAChR/PI3K/Akt-Dependent Survivin Upregulation

Transcatheter closure of perimembranous ventricular septal defects is one of the greatest challenges in interventional cardiology. Short- and midium-term follow-up data for large samples are limited. This report presents our experience with transcatheter closure of perimembranous ventricular septal defects using an occluder. Two hundred fifty-three patients included in the database of the Second Affiliated Hospital and Yuying Children’s Hospital from January 2011– December 2015 with transcatheter closure of perimembranous ventricular septal defects and discharged from follow-up. All patients were invited for clinical and transthoracic echocardiography, electrocardiogram, and thoracic radiography check-up. Device implantation was successful in 252 of 253 patients (99.6%). The median age was 42 months (range 27–216 months). The median follow-up duration was 36 months (range 6–60 months). The mean defect diameter was 3.5 ± 1.4 mm and the mean size of the ventricular septal defect rim below the aortic valve was 3.7 ± 1.8 mm. The mean diameter of the devices used was 4 mm. Thirty-seven patients developed arrhythmia after the procedure and recovered within 24 months; four patients had hemolysis and four had moderate tricuspid valve regurgitation. No other serious adverse event occurred during the follow-up period. Transcatheter closure of perimembranous ventricular septal defects using an occluder is safe and effective in most patients.

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Short- and medium-term follow-up of transcatheter closure of perimembranous ventricular septal defects

Viral myocarditis (VMC) is a widely studied but poorly understood inflammatory cardiomyopathy which mainly affects children and young adults and results in adverse outcomes. Cardiomyocyte apoptosis was reported important in the progress of coxsackievirus B3 (CVB3)-induced VMC and the blocking of this process may contribute to the therapeutic effect towards VMC. Therefore, this study was designed to explore whether survivin, one of the strongest antiapoptotic proteins, can protect cardiomyocytes from apoptosis in VMC and to discover its related mechanisms. Here, the cultured neonatal mouse cardiomyocytes (NMCs) were exposed to CVB3 to establish the cell model of VMC and the results of Western Blot showed that the protein expression of survivin in CVB3-infected NMCs varied at different post-infection time. Lentivirus was next used to examine the function of survivin in CVB3-infected NMCs. TUNEL assay demonstrated that the overexpression of survivin interrupted CVB3-induced apoptosis. It was next examined whether caspase-3 and -9 were involved in the antiapoptotic pathway initiated by survivin via Western Blot. The results showed a reverse relationship between the protein expression of survivin and that of cleaved caspase-3 and cleaved caspase-9, suggesting that survivin may attenuate apoptosis through restraining the activity of caspase-3 and -9. Moreover, the supernatant fluid of cultured NMCs was extracted to detect the quantitation of released lactate dehydrogenase (LDH) and a sharp decrease was discovered in the survivin-overexpressed group compared to the CVB3-infected group, indicating a protective role of survivin in the cell model of CVB3-induced myocarditis. This study demonstrated that survivin was triggered by CVB3 infection in NMCs and survivin executed its antiapoptotic effects via caspase-3- and caspase-9-dependent signaling pathway.

The protection effects of survivin in the cell model of CVB3-induced viral myocarditis.

Multiple atrial septal defects (ASDs) are one type of secundum ASD, most of which have an atrial septal aneurysm or long interdefect distance. In our retrospective single-center study, we reviewed different closure strategies for multiple ASDs. We analyzed 50 patients who underwent percutaneous transcatheter closure from May 2011 to July 2019. Information on the patients' characteristics, operation procedure, occluder selection, and complications was collected. According to the feature of the defects and device choice, multiple ASDs were divided into five groups. A successful operation was achieved in every patient. A total of 50 patients were implanted with 58 devices, with 26 patients implanted with a single standard ASD occluder (ASDO); six patients were implanted with double standard ASDOs, and only one patient was implanted with three standard ASDOs. There were 17 patients whose closure was made using the small-waist-big-edge ASDO. Seventy-six percent of the patients (38/50) had an immediate residual shunt. During the mean follow-up of 25.76 ± 22.53 months, the complete closure rate was 92%. Except for two patients with a transient atrioventricular block, individualized experience with percutaneous transcatheter closure for multiple ASDs was effective in a single-center study. After a mid- to long-term follow-up, the multiple ASDOs and small-waist-big-edge ASDO had no serious adverse events or complications.

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Yi Zhan

Papers

Piceatannol alleviates inflammation and oxidative stress via modulation of the Nrf2/HO-1 and NF-κB pathways in diabetic cardiomyopathy.

Nicotinic Agonist Inhibits Cardiomyocyte Apoptosis in CVB3-Induced Myocarditis via α3β4-nAChR/PI3K/Akt-Dependent Survivin Upregulation

Short- and medium-term follow-up of transcatheter closure of perimembranous ventricular septal defects

The protection effects of survivin in the cell model of CVB3-induced viral myocarditis.

Individualized Experience With Percutaneous Transcatheter Closure of Multiple Atrial Septal Defects: A Single-Center Study.