Alteration of lipids and the transcription of lipid-related genes in myelodysplastic syndromes via a TP53-related pathway

The prognostic value of the controlling nutritional status score in patients with myelodysplastic syndrome

PURPOSE

To evaluate the prognostic value of the controlling nutritional status score (CONUT) in patients with myelodysplastic syndrome (MDS).

METHODS

The clinical data of 81 newly diagnosed MDS patients treated with decitabine in the hematology ward of our hospital from October 2009 to September 2020 were analyzed retrospectively. According to the ROC curve of overall survival (OS), the best cutoff value of CONUT was obtained. MDS patients were divided into high CONUT score group and low CONUT score group according to the best cut-off value, and their clinical characteristics and survival were analyzed.

RESULTS

Among the 81 patients with MDS, there were 32 cases in the high CONUT score group and 49 cases in low CONUT score group. Compared with the low CONUT group, the high CONUT group had lower levels of hemoglobin, lymphocyte count, albumin, and total cholesterol (P = 0.037, < 0.001, 0.009, < 0.001). The median OS of low and high CONUT groups were 17.2 and 11.0 months (P = 0.017). According to the results of univariate and multivariate survival analysis of OS, thrombocytopenia, high CONUT score, and medium and high risk IPSS-R score were independent prognostic factors.

CONCLUSION

High CONUT score is associated with low hemoglobin in patients with MDS. High CONUT score indicates poor OS and it is an independent prognostic factor in patients with MDS.

Induction of microRNA hsa-let-7d-5p, and repression of HMGA2, contribute protection against lipid accumulation in macrophage 'foam' cells

Accumulation of excess cholesterol and cholesteryl ester in macrophage 'foam' cells within the arterial intima characterises early 'fatty streak' atherosclerotic lesions, and is accompanied by epigenetic changes, including altered expression of microRNA sequences which determine of gene and protein expression. This study established that exposure to lipoproteins, including acetylated LDL, induced macrophage expression of microRNA hsa-let-7d-5p, a sequence previously linked with tumour suppression, and repressed expression of one of its target genes, high mobility group AT hook 2 (HMGA2). A let-7d-5p mimic repressed expression of HMGA2 (18%; p < 0.05) while a marked increase (2.9-fold; p < 0.05) in expression of HMGA2 was noted in the presence of let-7d-5p inhibitor. Under these conditions, let-7d-5p mimic significantly (p < 0.05) decreased total (10%), free (8%) and cholesteryl ester (21%) mass, while the inhibitor significantly (p < 0.05) increased total (29%) and free cholesterol (29%) mass, compared with the relevant controls. Let-7d-5p inhibition significantly (p < 0.05) increased endogenous biosynthesis of cholesterol (38%) and cholesteryl ester (39%) pools in macrophage 'foam' cells, without altering the cholesterol efflux pathway, or esterification of exogenous radiolabelled oleate. Let-7d-5p inhibition in sterol-loaded cells increased the level of HMGA2 protein (32%; p < 0.05), while SiRNA knockdown of this protein (29%; p < 0.05) resulted in a (21%, p < 0.05) reduction in free cholesterol mass. Thus, induction of let-7d-5p, and repression of its target HMGA2, in macrophages is a protective response to the challenge of increased cholesterol influx into these cells; dysregulation of this response may contribute to atherosclerosis and other disorders such as cancer.

The anti-leukemic and lipid lowering effects of imatinib are not hindered by statins in CML: a retrospective clinical study and in vitro assessment of lipid-genes transcription

Imatinib, which has revolutionized chronic myeloid leukemia (CML) treatment, was suggested to improve lipid profile. Statins, a dyslipidemia drug, were reported to potentiate imatinib's antileukemic effect. However, analysis of imatinib combined with statins is lacking. We have retrospectively analyzed the normalization period of bcr-abl, blood counts, and lipids in 40 CML patients, 19 of which co-treated with statins, during short (<12 months) and prolonged (>12 months) imatinib treatment. Prior statins treatment did not hinder nor sensitized imatinib's anti-leukemic and lipid-lowering effects. CML cells (K562) treated with 1μM imatinib (24-96 h) were further assessed for the expression of central lipid-related genes by real-time PCR. HMGCoAR, LDL-R, and apobec1 expressions were significantly increased while CETP declined after 48-96 h. To conclude, imatinib produces an independent favorable lipid profile, which is not hindered by statins and is partly mediated via transcription regulation of genes involved in the clearance of plasma lipids.

The epigenetic drug 5-azacytidine interferes with cholesterol and lipid metabolism

DNA methylation and histone acetylation inhibitors are widely used to study the role of epigenetic marks in the regulation of gene expression. In addition, several of these molecules are being tested in clinical trials or already in use in the clinic. Antimetabolites, such as the DNA-hypomethylating agent 5-azacytidine (5-AzaC), have been shown to lower malignant progression to acute myeloid leukemia and to prolong survival in patients with myelodysplastic syndromes. Here we examined the effects of DNA methylation inhibitors on the expression of lipid biosynthetic and uptake genes. Our data demonstrate that, independently of DNA methylation, 5-AzaC selectively and very potently reduces expression of key genes involved in cholesterol and lipid metabolism (e.g. PCSK9, HMGCR, and FASN) in all tested cell lines and in vivo in mouse liver. Treatment with 5-AzaC disturbed subcellular cholesterol homeostasis, thereby impeding activation of sterol regulatory element-binding proteins (key regulators of lipid metabolism). Through inhibition of UMP synthase, 5-AzaC also strongly induced expression of 1-acylglycerol-3-phosphate O-acyltransferase 9 (AGPAT9) and promoted triacylglycerol synthesis and cytosolic lipid droplet formation. Remarkably, complete reversal was obtained by the co-addition of either UMP or cytidine. Therefore, this study provides the first evidence that inhibition of the de novo pyrimidine synthesis by 5-AzaC disturbs cholesterol and lipid homeostasis, probably through the glycerolipid biosynthesis pathway, which may contribute mechanistically to its beneficial cytostatic properties.

Emerging immunosuppressive drugs in myelodysplastic syndromes

INTRODUCTION

Myelodysplastic syndromes (MDS) are characterized by dysplastic morphologic features and ineffective hematopoiesis. Pathophysiological characteristics change over time making therapeutic development a major challenge. In early MDS, cytopenias arise or are exacerbated by humoral and cellular immune-mediators that suppress hematopoietic progenitor survival and alter the bone marrow microenvironment.

AREAS COVERED

In this review, current immunosuppressive regimens are described. To identify new therapies that may enhance immunosuppressive therapy (IST) response and identify pharmacodynamic biomarkers for patient selection, the inflammasome, cytokines, metabolic pathways and signaling events are described.

EXPERT OPINION

Agents with the potential to induce early, durable hematologic remissions are needed and many new immunosuppressive agents are available for investigation. An immune-mediated mechanism is likely to contribute to MDS early after diagnosis. New approaches that interfere with inflammatory pathways in the bone marrow microenvironment may move closer toward sustained disease control in MDS.