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The usage of doxorubicin is hampered by its life-threatening cardiotoxicity in clinical practice. Dexrazoxane is the only cardioprotective medicine approved by the FDA for preventing doxorubicin-induced cardiac toxicity. Nevertheless, the mechanism of dexrazoxane is incompletely understood. The aim of our study is to investigate the possible molecular mechanism of dexrazoxane against doxorubicin-induced cardiotoxicity. We established a doxorubicin-induced mouse and cardiomyocyte injury model. Male C57BL/6J mice were randomly distributed into a control group (Con), a doxorubicin treatment group (DOX), a doxorubicin plus dexrazoxane treatment group (DOX+DEX), and a dexrazoxane treatment group (DEX). Echocardiography and histology analyses were performed to evaluate heart function and structure. DNA laddering, qRT-PCR, and Western blot were performed on DOX-treated cardiomyocytes with/without DEX treatment in vitro. Cardiomyocytes were then transfected with miR-17-5p mimics or inhibitors in order to analyze its downstream target. Our results demonstrated that dexrazoxane has a potent effect on preventing cardiac injury induced by doxorubicin in vivo and in vitro by reducing cardiomyocyte apoptosis. MicroRNA plays an important role in cardiovascular diseases. Our data revealed that dexrazoxane could upregulate the expression of miR-17-5p, which plays a cytoprotective role in response to hypoxia by regulating cell apoptosis. Furthermore, the miRNA and protein analysis revealed that miR-17-5p significantly attenuated phosphatase and tensin homolog (PTEN) expression in cardiomyocytes exposed to doxorubicin. Taken together, dexrazoxane might exert a cardioprotective effect against doxorubicin-induced cardiomyocyte apoptosis by regulating the expression of miR-17-5p/PTEN cascade., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 Xiaoxue Yu et al.)

Doxorubicin, as a first line chemotherapeutic agent, its usage is limited owing to cardiotoxicity. Necroptosis is a new form of programmed cell death, and recent investigations indicated that necroptosis is vitally involved in serious cardiac pathological conditions. Dexrazoxane is the only cardiac protective drug approved by FDA for anthracycline. We aimed to explore whether and how dexrazoxane regulates doxorubicin-induced cardiomyocyte necroptosis. First, doxorubicin could cause heart failure and reduce cardiomyocyte viability by promoting cell apoptosis and necroptosis in vivo and in vitro. Second, necroptosis plays an important role in doxorubicin induced cardiomyocyte injury, which could be inhibited by Nec-1. Third, dexrazoxane increased cell viability and protect heart function by decreasing both cardiomyocyte apoptosis and necroptosis after doxorubicin treatment. Forth, dexrazoxane attenuated doxorubicin-induced inflammation and necroptosis by the inhibition of p38MAPK/NF-κB pathways. These results indicated that dexrazoxane ameliorates cardiotoxicity and protects heart function by attenuating both apoptosis and necroptosis in doxorubicin induced cardiomyocyte injury., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Claudin-6, a member of claudin family integral membrane proteins, has recently been reported to be a tumor suppressor for breast cancer. However, whether it plays a role in other types of cancer remains unclear. In the present study, we showed that the expression of claudin-6 is down-regulated in cervical carcinoma tissues as revealed by immunohistochemistry. Through over-expressing claudin-6 in HeLa and C33A cervical carcinoma cells, we found that claudin-6 is localized at plasma membrane and it increases transepithelial electrical resistance of the cells. Gain of claudin-6 expression suppresses cell proliferation, colony formation in vitro, and tumor growth in vivo. The effects are accompanied and potentially caused by promotion of tumor cell apoptosis. Taken together, these results suggest that claudin-6 may function as a tumor suppressor and loss of claudin-6 contributes to enhanced tumorigenic properties of cervical carcinoma cells.

Background: SIRT1, which belongs to the Sirtuin family of NAD-dependent enzymes, plays diverse roles in aging, metabolism, and disease biology. It could regulate cell survival and has been shown to be a protective factor in heart function. Hence, we verified the mechanism by which SIRT1 regulates doxorubicin induced cardiomyocyte injury in vivo and in vitro. Methods: We analyzed SIRT1 expression in doxorubicin-induced neonatal rat cardiomyocyte injury model and adult mouse heart failure model. SIRT1 was over-expressed in cultured neonatal rat cardiomyocyte by adenovirus mediated gene transfer. SIRT1 agonist resveratrol was used to treat the doxorubicin-induced heart failure mouse model. Echocardiography, reactive oxygen species (ROS) production, TUNEL, qRT-PCR, and Western blotting were performed to analyze cell survival, oxidative stress, and inflammatory signal pathways in cardiomyocytes. Results: SIRT1 expression was down-regulated in doxorubicin induced cardiomocyte injury, accompanied by elevated oxidative stress and cell apoptosis. SIRT1 over-expression reduced doxorubicin induced cardiomyocyte apoptosis with the attenuated ROS production. SIRT1 also reduced cell apoptosis by inhibition of p38MAPK phosphorylation and caspase-3 activation. The SIRT1 agonist resveratrol was able to prevent doxorubicin-induced heart function loss. Moreover, the SIRT1 inhibitor niacinamide could reverse SIRT1's protective effect in cultured neonatal rat cardiomyocytes. Conclusions: These results support the role of SIRT1 as an important regulator of cardiomyocyte apoptosis during doxorubicin-induced heart injury, which may represent a potential therapeutic target for doxorubicin-induced cardiomyopathy. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]