Project description:Doxorubicin (Dox) is a widely used treatment for cancer, which can result in chemotherapy induced cognitive impairments (chemobrain). Chemobrain is associated with inflammation and oxidative stress similar to aging. As such, Dox treatment has also been used as a model of aging. However, it is unclear if Dox induces brain changes similar to that observed during aging, since Dox does not readily enter the brain. Rather, the mechanism for chemobrain likely involves induction of peripheral cellular senescence and the release ofsenescence-associated secretory phenotype (SASP) factors, which enter the brain to disrupt cognition. We examined the effect of Dox on peripheral and brain markers of aging and cognition. In addition, we employed the senolytic, ABT-263, which also has limited access to the brain. While Dox treatment influenced several measures linked to aging, including peripheral inflammation, morphological measure of microglial activation, cognition, and synaptic function,the effects of Dox treatment on brain (i.e. dentate gyrus) gene expression did not approximate aging to the same degree as other measures.Regardless, ABT-263 prevent or limited most of the Dox induced effects, including brain gene expression. The resultsemphasize a link between cognitive decline and the release of SASP factors from peripheral senescent cells and indicate thatdifferences between aging and Dox treatment on brain gene expression are important in considering Dox treatment as a model of aging.
Project description:Angiosarcoma is an aggressive soft-tissue sarcoma with a poor prognosis. Chemotherapy for this cancer typically employs paclitaxel, one of the taxanes (genotoxic drugs), although it has a limited effect due to chemoresistance for prolonged treatment. Here we examine a new angiosarcoma treatment approach that combines chemotherapeutic and senolytic agents. We first find that the chemotherapeutic drugs, cisplatin and paclitaxel, efficiently induce cellular senescence of angiosarcoma cells. Subsequent treatment with a senolytic agent, ABT-263, eliminates senescent cells through the activation of the apoptotic pathway. In addition, expression analysis indicates that senescence-associated secretory phenotype (SASP) genes are activated in senescent angiosarcoma cells and that ABT-263 treatment eliminates senescent cells expressing genes in the type-I interferon (IFN-I) pathway. Moreover, we show that cisplatin treatment alone requires a high dose to remove angiosarcoma cells, whereas a lower dose of cisplatin is sufficient to induce senescence, followed by the elimination of senescent cells by senolytic treatment. This study sheds light on a potential therapeutic strategy against angiosarcoma by combining a relatively low dose of cisplatin with the ABT-263 senolytic agent, which can help ease the deleterious side effects of chemotherapy.
Project description:Doxorubicin as a commonly used anthracycline has become the cornerstone of chemotherapy in a wide range of cancers owing to its high efficacy. However, clinical applications of doxorubicin are limited mainly due to its toxic effects on myocardium but the pathogenic mechanism of doxorubicin-induced cardiomyopathy are poorly understood. ADAM17 is known as tumor necrosis factor α converting enzyme (TACE), and the cleavage of TNF-α by ADAM17 is a prerequisite for pro-inflammatory TNF-α activity, which raises a possibility that inhibition of ADAM17 may exert a beneficial effect on disease processes where TNF-α plays an essential role. Our previous research has shown that cardiomyocyte specific knockout of ADAM17 improves diabetic cardiomyopathy by modulating cardiomyocyte apoptosis. However, the relationship between ADAM17 and doxorubicin-induced cardiomyopathy is unclear.Through RNA sequencing analysis, we observed significant changes in the TNF signaling pathway genes in the heart tissue of mice with or without cardiomyocyte ADAM17 knockout.
Project description:In the treatment of cancer with chemotherapeutics, it has been observed that a significant amount of cancer cells turn into senescent cells. These senescent cells secrete several factors in their microenvironment called SASP. Therefore, recently, to develop the senolytic and/or senomorphic drugs, targeting the senescent cells gains importance as a new strategy for preventing the damage that senescent cancer cells cause. In the current work, we evaluated whether Rho/Rho kinase pathway has a potential to be used as a target pathway for the development of senolytic and/or senomorphic drugs, in doxorubicin-induced senescent cancer cell lines. We performed a whole-genome microarray analysis to determine how the expressions of SASP factors change in senescent cells and whether ROCK inhibition also causes changes in the expression of these factors.
Project description:Selective removal of senescent cells, or the concept of senolytic therapy, has been proposed to be a potent strategy for overcoming age-related diseases and even reversing aging. We found that nintedanib, a tyrosine kinase inhibitor, selectively induced cell death in primary human diploid fibroblasts undergoing replicative senescence. Similar to ABT263, a well-known senolytic agent, nintedanib triggered intrinsic apoptosis in senescent cells. Additionally, at the concentration producing the senolytic effect, nintedanib arrested the cell cycle of nonsenescent cells in the G1 phase without cytotoxicity. Interestingly, compared with ABT263, nintedanib showed a different mode of activating caspase-9 in the intrinsic apoptotic pathway, in that nintedanib did not suppress the levels of Bcl-2 family proteins in senescent cells. In more detail, nintedanib suppressed the activation of the JAK2/STAT3 pathway, which caused drug-induced cell death in senescent cells. STAT3 knockdown in senescent cells also induced caspase activation. Moreover, nintedanib reduced the number of senescent cells stained based on senescence-associated β-galactosidase activity and airway resistance in a mouse model of bleomycin-induced lung fibrosis. Overall, we identified that nintedanib could be used as a new senolytic agent and that inhibiting STAT3 could be a potential approach for inducing selective cell death in senescent cells. Our findings will pave the way for expanding senolytic toolkits in response to various aging statuses and age-related diseases.
Project description:Doxorubicin (Dox) is an effective chemotherapeutic agent against a broad range of tumors. However, a threshold dose of doxorubicin causes an unacceptably high incidence of heart failure and limits its clinical utility. We have established two models of doxorubicin cardiotoxicity in mice: 1) in an acute model, mice are treated with 15mg/kg of doxorubicin once; 2) in a chronic model, they receive 3mg/kg weekly for the first 12 of a total of 18 weeks. Using echocardiography, we have monitored left ventricular function of the mouse hearts during treatment in chronic model and seen the expected development of dilated cardiomyopathy (DCM). Treated mice showed histological abnormalities similar to those seen in patients with doxorubicin cardiomyopathy. To investigate transcriptional regulation in these models, we used a microarray we generated with over 5000 independent cDNA clones from murine heart and skeletal muscle. We have identified genes that respond to doxorubicin exposure in both model systems, and confirmed these results using real-time PCR. In the acute model, a set of genes is regulated early and rapidly returns to baseline levels, consistent with the half-life of doxorubicin. In the chronic model, which mimics the clinical situation much more closely, we identified dysregulated genes that implicate specific mechanisms of cardiac toxicity and may serve as biomarkers of doxorubicin induced dilated cardiomyopathy. Keywords: time course
Project description:To compare expression profiles in the cardiomyocytes with wild type top2b and those with top2b deletion after in vivo treatment of mice with doxorubicin or drug vehicle Doxorubicin is widely used in modern cancer treatments, despite the advent of targeted therapy. However, a dose-dependent cardiotoxicity often limits its clinical use. The prevailing theory hypothesizes that doxorubicin-induced cardiotoxicity is the result of reactive oxygen species (ROS) generation due to redox-cycling of doxorubicin. Here we showed that cardiomyocyte-specific deletion of Topoisomerase II beta (Top2b) markedly reduced DNA double-strand breaks, apoptosis, and functional damages in doxorubicin-treated hearts. To investigate transcriptomic changes after doxorubicin treatment in wild type mouse and mouse with cardiac specific deletion of Top2b, we examined the expression profiles in 4 groups of mice (3/group), ie. wildtype mice with or without doxorubicin treatment and mice with Top2b deletion in the cardiomyocytes with or without doxorubicin treatment. Mice were treated with doxorubicin (25mg/kg, i.p.) or PBS (drug vehicle) for 16 hr or 72 hr. The heart was removed and cardiomyocytes were isolated by using a Langendorff apparatus. After purification, total RNA was extracted from the cardiomyocytes, purified, and used for gene expression analysis. Compared with that in control cardiomyocytes or cardiomyocytes with Top2b deletion, doxorubicin caused a significant expression change in the genome of cardiomyocytes from the wildtype mice. Among the changes, multiple genes encoding mitochondrial structural protein and components of the respiratory chain complexes were down-regulated 72 hr after treatment while multiple genes in the p53 pathway were up-regulated 16 hr after treatment in the wildtype cardiomyocytes.