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A Novel Approach to Safer Glucocorticoid Receptor-Targeted Anti-lymphoma Therapy via REDD1 (Regulated in Development and DNA Damage 1) Inhibition.

ABSTRACT: Glucocorticoids are widely used for therapy of hematologic malignancies. Unfortunately, chronic treatment with glucocorticoids commonly leads to adverse effects including skin and muscle atrophy and osteoporosis. We found recently that REDD1 (regulated in development and DNA damage 1) plays central role in steroid atrophy. Here, we tested whether REDD1 suppression makes glucocorticoid-based therapy of blood cancer safer. Unexpectedly, approximately 50% of top putative REDD1 inhibitors selected by bioinformatics screening of Library of Integrated Network-Based Cellular Signatures database (LINCS) were PI3K/Akt/mTOR inhibitors. We selected Wortmannin, LY294002, and AZD8055 for our studies and showed that they blocked basal and glucocorticoid-induced REDD1 expression. Moreover, all PI3K/mTOR/Akt inhibitors modified glucocorticoid receptor function shifting it toward therapeutically important transrepression. PI3K/Akt/mTOR inhibitors enhanced anti-lymphoma effects of Dexamethasone in vitro and in vivo, in lymphoma xenograft model. The therapeutic effects of PI3K inhibitor+Dexamethasone combinations ranged from cooperative to synergistic, especially in case of LY294002 and Rapamycin, used as a previously characterized reference REDD1 inhibitor. We found that coadministration of LY294002 or Rapamycin with Dexamethasone protected skin against Dexamethasone-induced atrophy, and normalized RANKL/OPG ratio indicating a reduction of Dexamethasone-induced osteoporosis. Together, our results provide foundation for further development of safer and more effective glucocorticoid-based combination therapy of hematologic malignancies using PI3K/Akt/mTOR inhibitors.

SUBMITTER: Lesovaya EA

PROVIDER: S-EPMC7875139 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature

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A Novel Approach to Safer Glucocorticoid Receptor-Targeted Anti-lymphoma Therapy via REDD1 (Regulated in Development and DNA Damage 1) Inhibition.

Lesovaya Ekaterina A EA Savinkova Alena V AV Morozova Olga V OV Lylova Evgeniya S ES Zhidkova Ekaterina M EM Kulikov Evgeny P EP Kirsanov Kirill I KI Klopot Anna A Baida Gleb G Yakubovskaya Marianna G MG Gordon Leo I LI Readhead Ben B Dudley Joel T JT Budunova Irina I

Molecular cancer therapeutics 20200616 9

Glucocorticoids are widely used for therapy of hematologic malignancies. Unfortunately, chronic treatment with glucocorticoids commonly leads to adverse effects including skin and muscle atrophy and osteoporosis. We found recently that REDD1 (regulated in development and DNA damage 1) plays central role in steroid atrophy. Here, we tested whether REDD1 suppression makes glucocorticoid-based therapy of blood cancer safer. Unexpectedly, approximately 50% of top putative REDD1 inhibitors selected b ...[more]

PMID: 32546661

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Project description:We found earlier that ectopic expression of the cytidine deaminase APOBEC3G (A3G) in Vero cells inhibits measles virus (MV), respiratory syncytial virus, and mumps virus, while the mechanism of inhibition remained unclear. A microarray analysis revealed that in A3G-transduced Vero cells, several cellular transcripts were differentially expressed, suggesting that A3G regulates the expression of host factors. One of the most upregulated host cell factors, REDD1 (regulated in development and DNA damage response-1, also called DDIT4), reduced MV replication ?10-fold upon overexpression in Vero cells. REDD1 is an endogenous inhibitor of mTORC1 (mammalian target of rapamycin complex-1), the central regulator of cellular metabolism. Interestingly, rapamycin reduced the MV replication similarly to REDD1 overexpression, while the combination of both did not lead to further inhibition, suggesting that the same pathway is affected. REDD1 silencing in A3G-expressing Vero cells abolished the inhibitory effect of A3G. In addition, silencing of A3G led to reduced REDD1 expression, confirming that its expression is regulated by A3G. In primary human peripheral blood lymphocytes (PBL), expression of A3G and REDD1 was found to be stimulated by phytohemagglutinin (PHA) and interleukin-2. Small interfering RNA (siRNA)-mediated depletion of A3G in PHA-stimulated PBL reduced REDD1 expression and increased viral titers, which corroborates our findings in Vero cells. Silencing of REDD1 also increased viral titers, confirming the antiviral role of REDD1. Finally, pharmacological inhibition of mTORC1 by rapamycin in PHA-stimulated PBL reduced viral replication to the level found in unstimulated lymphocytes, indicating that mTORC1 activity supports MV replication as a proviral host factor.IMPORTANCE Knowledge about host factors supporting or restricting virus replication is required for a deeper understanding of virus-cell interactions and may eventually provide the basis for therapeutic intervention. This work was undertaken predominantly to explain the mechanism of A3G-mediated inhibition of MV, a negative-strand RNA virus that is not affected by the deaminase activity of A3G acting on single-stranded DNA. We found that A3G regulates the expression of several cellular proteins, which influences the capacity of the host cell to replicate MV. One of these, REDD1, which modulates the cellular metabolism in a central position by regulating the kinase complex mTORC1, was identified as the major cellular factor impairing MV replication. These findings show interesting aspects of the function of A3G and the dependence of the MV replication on the metabolic state of the cell. Interestingly, pharmacological inhibition of mTORC1 can be utilized to inhibit MV replication in Vero cells and primary human peripheral blood lymphocytes.

Project description:Even though cutaneous atrophy is the major adverse effect of topical glucocorticoids, its molecular mechanisms are poorly understood. We found that glucocorticoids strongly increased the expression of REDD1 (regulated in development and DNA damage response 1), a stress-inducible inhibitor of mTOR, in mouse and human epidermis. We found that REDD1 knockout animals are partially resistant to glucocorticoid-induced epidermal and subcutaneous adipose atrophy which correlated with the protection of CD34+ follicular epithelial stem cells as well as p63+ keratinocyte progenitors in REDD1 knockout epidermis during chronic steroid treatment. At the same time, REDD1 knockout did not affect anti- inflammatory effect of glucocorticoids, as evaluated by ear edema test. Expression profiling revealed that ~ 50% of the glucocorticoid receptor (GR) target genes were not activated in epidermis of REDD1 knockouts, however, the negative effect of glucocorticoids on gene expression was similar to that in w.t. animals. Overall, our findings reveal a novel pathway in GR activation by its target gene/protein REDD1; and indicate an important role of REDD1 in glucocorticoid-induced skin atrophy, and maintenance of the epidermis and subcutaneous adipose. In addition, our findings form the foundation for the development of safer topical glucocorticoid treatment regimens by combining this therapy with REDD1 inhibitors. Seven wk old B6D2 females in the telogen stage of the hair cycle were shaved, and treated 3 days later. Glucocorticoid FA was applied topically (2 ug/animal) in 200 ul acetone to the back skin once or up to four applications every third day as described previously (Chebotaev et al., 2007b). Control animals were treated with acetone only. Skin was harvested 24 h after last FA application or 4-8 h after single FA application as indicated in Figure legends. To evaluate the anti-inflammatory effect of glucocorticoid FA in REDD1 KO and w.t. B6x129 mice, we used ear edema test (Schoepe et al., 2010; Schäcke et al., 2004; Park et al., 2006). Seven wk old female animals were pretreated with FA or vehicle applied to the back of the ear lobe one h before application of nonspecific contact irritant croton oil . Mice were sacrificed and ears were harvested nine hours after CO application, the time point at which we observed maximum ear edema in F1 C57Bl x 129 animals (data not shown). Four mm ear punch biopsies were immediately weighted to assess ear edema. Animals were injected i.p. with bromodeoxyuridine 1 hr before skin was harvested. Total RNA from murine epidermis and whole human skin was isolated with RiboPure kit (Ambion). Total RNA from murine s.c. adipose was isolated with RNeasy Lipid Tissue Kit (Qiagen). The RNA samples were treated with TURBOTM DNase (Ambion). Purity of RNA samples isolated from epidermis and s.c. fat was confirmed by the expression of adipose and keratinocyte cell markers.

Dataset Information

A Novel Approach to Safer Glucocorticoid Receptor-Targeted Anti-lymphoma Therapy via REDD1 (Regulated in Development and DNA Damage 1) Inhibition.

Publications

A Novel Approach to Safer Glucocorticoid Receptor-Targeted Anti-lymphoma Therapy via REDD1 (Regulated in Development and DNA Damage 1) Inhibition.

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