Molecular basis of multiple myeloma.

BACKGROUND: Multiple myeloma (MM) is a heterogeneous hematological malignancy characterized by clonal expansion of malignant plasma cells in the bone marrow. The disease is accompanied by various clinical manifestations, such as bone lesions, anemia, hypercalcemia, and renal insufficiency. However, despite significant advances in treatment over the last two decades, the disease remains challenging to treat, and most patients relapse. Although its pathogenesis has not yet been elucidated, it is clear that genomic instability plays a key role in its develop-ment or resistance to treatment. In some instances, the cause of this instability is chromothripsis, a form of complex genomic rearrangement that involves shattering and subsequent haphazard reassembly of chromosomes within a single catastrophic event. The resulting rearrangements involve a variety of structural changes, including deletions, duplications, inversions, and translocations, that lead to genome disruption. Specifically, these changes may result in alteration or inactivation of tumor suppressor genes (TP53 and CDKN2C), activation of oncogenes (MAF, FGFR3, and CCND1) or genes involved in key cellular processes. Unraveling the mechanisms that result in chromothripsis provides opportunities to identify critical genes and pathways involved in MM pathogenesis. These findings may serve as a basis for improved dia-gnostic approaches. PURPOSE: The goal of this review is to summarize the common primary and secondary chromosomal aberrations in MM with a particular focus on introducing complex chromosomal aberrations, especially chromothripsis in MM.

The endoplasmic reticulum and its signaling pathways - a novel target for multiple myeloma treatment.

BACKGROUND: The endoplasmic reticulum (ER), an organelle composed of a system of cisternae and tubules, is essential for many cellular processes, including protein synthesis and transport. When misfolded proteins accumulate in the ER lumen, ER stress is induced, and the subsequent response to the disruption of homeostasis is the activation of the unfolded protein response (UPR). The purpose of this process is to restore homeostasis by increasing the capacity of the ER and its ability to fold proteins. Activation of the homeostatic UPR occurs via one of three transmembrane proteins, inositol-requiring enzyme 1a (IRE1a), protein kinase R-like ER kinase (PERK) and activating transcription factor 6 (ATF6). Failure of the attempt to restore homeostasis, on the other hand, leads to the development of terminal UPR and apoptosis via hyperactivation of the same proteins. Activation of UPR has been described in many malignancies, including multiple myeloma (MM), which is characterized by malignant transformation of plasma cells and increased monoclonal immunoglobulin synthesis, where the role of the ER is of particular importance. Despite advances in the treatment of MM, the disease remains difficult to treat and targeting signaling pathways associated with the UPR could, for example, enhance the effect of proteasome inhibitors. PURPOSE: This review intends to present the molecular response to ER stress under physiological circumstances and in the context of cancer, particularly with regard to potential therapeutic targets in MM.

Erdheim-Chester disease.

Erdheim-Chester disease is a rare inflammatory myeloid clonal disease which is classified into histiocytoses. It is characterized by excessive production and accumulation of foamy histiocytes and Touton giant cells in various tissues and organs. Foamy histiocytes and Touton giant cells produce proinflammatory cytokines and chemokines and contain somatic mutations in genes activating the MAPK/ERK signaling pathway, but also in genes activating the PI3K/AKT signaling pathway. BRAFV600E is the most common somatic mutation. Furthermore, somatic mutations in the MAP2K1, KRAS, NRAS, ARAF or PIK3CA genes are abundant. Erdheim-Chester dis-ease is a multisystemic disease in which any organ can be affected, especially the long bones of the lower extremities, but also the cardiovascular system, retroperitoneum, endocrine system, central nervous system, lungs, skin or orbit. The dia-gnosis is difficult because of the various manifestations of this disease. The disease occurs mainly in adults and is more common in men than in women. Targeted treatment by kinase inhibitors, interferon a, cytokine blockers or cladribine is used for the treatment.

Waldenström macroglobulinemia.

BACKGROUND: Waldenström macroglobulinemia (WM) is a hematological malignancy; it is a monoclonal gammopathy, a disease characterized by presence of a monoclonal immunoglobulin in serum and/or urine. The median age at dia-gnosis is 71 years. WM is not an aggres-sive disease and patients with this dia-gnosis can live for several years. Infiltration of the bone marrow with lymphoplasmacytoid cells causes anemia, leading to various problems, mainly fatigue. Hepatomegaly, splenomegaly and lymphadenopathy can also occur. Hyperviscosity syndrome can appear and is caused by excessive production of immunoglobulin M. A mutation in MYD88 gene is detected in almost every WM patient, and in almost one third of them, a mutation in CXCR4 gene is detected. The detection of MYD88 mutation is important for a correct therapeutic strategy, since a Brutons tyrosine kinase inhibitor, ibrutinib, is most effective in patients with mutated MYD88 and wt CXCR4. The therapy is started when first symptoms occur. PURPOSE: The aim of this study is to summarize current knowledge about this disease, its dia-g-nostics, molecular basis and treatment.

Role of exosomes in malignancies.

BACKGROUND: Extracellular vesicles are closed structured surrounded by a lipid membrane that are secreted by almost all types of cells; their function is information delivery during cell-to-cell communication. They are most commonly divided into three categories - exosomes, microvesicles and apoptotic bodies. Exosomes are small vesicles with the size of 30-100 nm, and they are found in almost all body fluids, including peripheral blood, urine, breast milk, saliva and others. They are able to deliver their content to target cells and change their behavior. Cancer cells are able to secrete more exosomes and also contain different proteins and RNA species than the exosomes from healthy cells. Due to their specific composition that is connected to the cell of origin, exosomes could be used as bio-markers of various diseases in the future. PURPOSE: The aim of this work is to summarize current knowledge about exosomes and their role in various processes connected to resistance in tumors. This work was supported by grant of the Ministry of Health of the Czech Republic AZV 17-29343A. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.

[MicroRNA Analysis for Extramedullary Multiple Myeloma Relapse]. / Analýza mikroRNA u extramedulárního relapsu mnohocetného myelomu.

INTRODUCTION AND AIMS: Multiple myeloma (MM) is the second most common hematooncological disease. Patient survival has been greatly improved by the introduction of new drugs into clinical practice, but survival is negatively affected by the so-called extramedullary relapse (EM), caused by the loss of plasma cell dependence on the bone marrow microenvironment and their migration out of the bone marrow. The nature and causes of this process are currently unclear. MicroRNAs (miRNAs) are short, non-coding RNA molecules involved in many physiological and pathological processes. Their significance in the pathogenesis of MM has been demonstrated by several studies. We assume that they are also involved in the development of the EM. The aim of this study was to analyze different miRNA expression between MM and EM patients. MATERIAL AND METHODS: Using next generation sequencing, we analyzed 39 samples of bone marrow cells from MM patients at diagnosis and 9 bone marrow plasma samples of EM patients. RESULTS: In total, 2,278 miRNA were sequenced, but only 658 miRNAs were analyzed as they were expressed in all samples and had at least 20 reads. Expression data were generated using the Chimira tool from fastq data. All sequences were mapped using miRBase v20. Further analyses were performed using the R/Bioconductor package. The Bayesian procedure was used for normalization of expression. P values were adjusted using the Benjamini-Hochberg method. Analysis found 10 miRNA (p < 0.0005) that are statistically significantly expressed in EM vs. MM patients - these are miR-26a-5p, miR-26b-5p, miR-30e-5p, miR-424-3p, miR-503-5p, miR-767-5p, miR-105-5p, miR-5695-5p, miR-450b-5p and miR-92b-3p. These miRNAs will be further verified by qPCR method on a larger set of MM and EM patients. CONCLUSION: Our pilot study has shown that there are differentially expressed miRNAs between MM and EM patients.Key words: multiple myeloma - microRNA - carcinogenesis - next generation sequencing The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papersThis work was supported by grant MZ CR AZV 17- 29343A. Submitted: 17. 3. 2018Accepted: 20. 3. 2018.

Inhibition of aromatic amino acid decarboxylase by a group of non-steroidal anti-inflammatory drugs.

In vitro inhibition of aromatic amino acid decarboxylase (AAD) by eight nonsteroidal anti-inflammatory drugs (NSAIDs) was studied. The most potent inhibitors were fenamates (IC50 for tolfenamate was 4.4 x 10(-5) M), while fluorinated biphenylic compounds (flobufen and 2',4'-difluorobiphenyl-4-yl acetate) and propionic acid derivatives (ibuprofen, ketoprofen, fenoprofen) were one order weaker. The in vitro inhibition of AAD by the compounds studied is probably not strong enough to contribute to their in vivo anti-inflammatory effects.