Regulated in Development and DNA Damage Response 1 (REDD1)/DNA Damage-Induced Transcript 4 (DDIT4) is an immediate early response gene activated by different stress conditions, including growth factor depletion, hypoxia, DNA damage, and stress hormones, i.e., glucocorticoids. The most known functions of REDD1 are the inhibition of proliferative signaling and the regulation of metabolism via the repression of the central regulator of these processes, the mammalian target of rapamycin (mTOR). The involvement of REDD1 in cell growth, apoptosis, metabolism, and oxidative stress implies its role in various pathological conditions, including cancer and inflammatory diseases. Recently, REDD1 was identified as one of the central genes mechanistically involved in undesirable atrophic effects induced by chronic topical and systemic glucocorticoids widely used for the treatment of blood cancer and inflammatory diseases. In this review, we discuss the role of REDD1 in the regulation of cell signaling and processes in normal and cancer cells, its involvement in the pathogenesis of different diseases, and the approach to safer glucocorticoid receptor (GR)-targeted therapies via a combination of glucocorticoids and REDD1 inhibitors to decrease the adverse atrophogenic effects of these steroids.

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.

Previously we discovered that among 15 DNA-binding plant secondary metabolites (PSMs) possessing anticancer activity, 11 compounds cause depletion of the chromatin-bound linker histones H1.2 and/or H1.4. Chromatin remodeling or multiH1 knocking-down is known to promote the upregulation of repetitive elements, ultimately triggering an interferon (IFN) response. Herein, using HeLa cells and applying fluorescent reporter assay with flow cytometry, immunofluorescence staining and quantitative RT-PCR, we studied effects of PSMs both evicting linker histones from chromatin and not influencing their location in nucleus. We found that (1) 8 PSMs, evicting linker histone H1.2 from chromatin, activated significantly the type I IFN signaling pathway and out of these compounds resveratrol, berberine, genistein, delphinidin, naringenin and curcumin also caused LINE1 expression. Fisetin and quercetin, which also induced linker histone H1.2 eviction from chromatin, significantly activated only type I IFN signaling, but not LINE1 expression; (2) curcumin, sanguinarine and kaempferol, causing significant depletion of the chromatin-bound linker histone H1.4 but not significantly influencing H1.2 presence in chromatin, activate type I IFN signaling less intensively without any changes in LINE1 expression; (3) four PSMs, which did not cause linker histone eviction, displayed neither IFN signaling activation nor enhancement of LINE1 expression. Thus, we have shown for the first time that chromatin destabilization observed by depletion of chromatin-bound linker histone H1.2 caused by anticancer DNA-binding PSMs is accompanied by enhancement of type I IFN signaling, and that LINE1 expression often impacts this activation.

Aim. Evaluation of the clinical characteristics in patients with COVID-19. Materials and methods. The article presents clinical and instrumental data of 1169 patients included in a single-center mixed study. Patients were tested for COVID-19 using polymerase chain reaction, computed tomography (CT), and antibody screening. Clinical history data were collected. Results. In patients with confirmed COVID-19, lung damage and a positive test for antibodies were observed in 75.5 and 45.2% of cases, respectively. The most common symptoms of COVID-19 were: fever (73.2%), weakness, (72.7%) dry cough (62.8%) and shortness of breath (55.4%). Patients with CT-visualized lung lesions were more likely to have clinical symptoms and elevated levels of antibodies. Patients with chronic diseases of the endocrine system, circulatory system, and respiratory system had a more severe course of the disease (CT-14: 91.296.3%) than patients without chronic diseases (CT-14: 85,1%). Conclusion. We have compiled a clinical profile of patients with COVID-19 and highlighted the most significant clinical characteristics corresponding to a more severe course of the disease. Our data showed that patients with chronic diseases require a personalized approach and the development of specific criteria for the diagnosis and treatment of COVID-19.

Glucocorticoids (GC ) have been an integral component of the treatment of leukemias and lymphomas for several decades. Specific cytotoxic effect of GC on transformed lymphoblasts mediates their use at the stage of the remission induction as well as consolidation of treatment. However, the main problem of the long-term GC use is the development of atrophic and metabolic side effects as well as GC resistance. The biological effects of GC are realized via activation of the glucocorticoid receptor (GR) by two mechanisms: transrepression (TR) associated with the therapeutic effects of GC , and transactivation (TA ), which mediates the development of metabolic and atrophic complications. It was demonstrated that an increase in the expression of the GC - dependent gene REDD1 associated with GC -induced skin, muscle and bone atrophy of the skin, muscle and bone tissue was realized via the induction of transactivation. Therefore, identification of potential inhibitors of REDD1 expression and study of their biological effects in combination with GC in models of leukemia and lymphoma is of particular interest. In our recent study we have selected a number of drugs from the class of PI 3K/Akt/mTO R modulators using bioinformatic screening. These drugs effectively inhibited REDD1 expression, modulated GR activity and shifted it towards transrepression, and prevented the development of GC -induced side effects in mice. Here we aimed to study the effects of potential inhibitors of REDD1 expression from different pharmacological groups, the compounds Emetine and CGP -60474, on leukemia and lymphoma cells in combination with GC . We demonstrated antitumor effect of the compounds in vitro, a decrease in the expression of TA -associated genes and an increase in TR induction. Further studies of the antitumor effects of REDD1 expression inhibitors (Emetine and CGP -60474 is a promising area of research.

Supplementary Figures 1-9. Suppl. Fig. 1 contains quantification of Western blots. Suppl. Fig. 2 demonstrates the effect of PI3K/mTOR/Akt inhibitors on regulation of endogenous genes by Dex in CEM and Granta cells. Suppl. Fig. 3 shows cytotoxic effects of LY294002, Wortmannin and AZD8055 on CEM and Granta cells. Suppl. Fig. 4 demonstrates cytotoxic effects of LY294002, Wortmannin and AZD8055 on CEM cells, Granta cells and normal human monocytes. Suppl. Fig. 5 shows anti-lymphoma effect of Rapamycin and Dex in CEM and Granta cells. Suppl. Fig. 6 demonstrates the effect of LY294002, Rapamycin and Dex on animal body weight in xenograft study. Suppl. Fig. 7 shows anti-tumor effect of Dex, Rapa, LY294002 on Granta xenografts. Suppl. Fig. 8 demonstrates the effect of LY294002, Rapamycin and Dex on animal body weight in Dexamethasone-induced osteoporosis study. Suppl. Fig. 9 shows the data on Q-PCR analysis of Col1a1 and Col2a1 mRNA expression in bone tissue.