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: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:Senescent cells accumulate in organisms over time as a result of tissue damage and impaired immune surveillance and are thought to contribute to age-related tissue decline1,2. In agreement, genetic ablation studies reveal that elimination of senescent cells from aged tissues can ameliorate various age-related pathologies, including metabolic dysfunction and decreased physical fitness3-7. While small-molecule drugs capable of eliminating senescent cells (known as ‘senolytics’) partially replicate these phenotypes, many have uncertain mechanisms of action and all require continuous administration to be effective. As an alternative approach, we previously developed a cell-based senolytic therapy based on chimeric antigen receptor (CAR) T cells targeting uPAR, a cell-surface protein upregulated on senescent cells, and showed these can safely and efficiently eliminate senescent cells in young animals and reverse liver fibrosis8. We now show that uPAR-positive senescent cells accumulate during physiological aging and that they can be safely targeted with senolytic CAR T cells in aged animals. Treatment with anti uPAR CAR T cells ameliorates metabolic dysfunction by improving glucose tolerance and exercise capacity in physiological aging as well as in a model of metabolic syndrome. Importantly, the beneficial effects of senolytic CAR T cells are long lasting; single administration of a low dose is sufficient to achieve long-term therapeutic and preventive effects.
Project description:Senolytics, drugs that kill senescent cells, have been proposed to improve the response to pro-senescence cancer therapies. However, lack of broadly acting senolytic drugs remains a challenge. Using inducible CRISPR/Cas9-based genetic screens in different senescent cancer cell models, we identify here loss of the death receptor inhibitor cFLIP as a universal vulnerability of senescent cancer cells. Senescent cancer cells are primed for apoptotic death by NF-kB-mediated upregulation of death receptor DR5 and its ligand TRAIL but are protected from death by increased cFLIP. Activation of DR5 signaling by agonistic antibody, which can be enhanced further by suppression of cFLIP by BRD2 inhibition, leads to efficient killing of all senescent cancer cells tested. We validate this ?one-two punch? cancer therapy by combining pro-senescence therapy with DR5 activation in different animal models.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
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:Although cellular senescence acts primarily as a tumor suppression mechanism, the accumulation of senescent cells in vivo eventually exerts deleterious side effects through inflammatory/tumor-promoting factor secretion. Thus, the development of new drugs that cause the specific elimination of senescent cells, termed senolysis, is anticipated. Here, by an unbiased high-throughput screening of chemical compounds and a bio-functional analysis, we identify ARV825 as a promising senolytic drug. ARV825 treatment eliminates senescent hepatic stellate cells in obese mouse livers, accompanied by the reduction of liver cancer development. Furthermore, the elimination of chemotherapy-induced senescent cells by ARV825 increases the efficacy of chemotherapy against xenograft tumors in immunocompromised mice. These results reveal the vulnerability of senescent cells and open up possibilities for its control.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.