Lenka Sedlarikova

TGF-β - an excellent servant but a bad master.

The transforming growth factor (TGF-β) family of growth factors controls an immense number of cellular responses and figures prominently in development and homeostasis of most human tissues. Work over the past decades has revealed significant insight into the TGF-β signal transduction network, such as activation of serine/threonine receptors through ligand binding, activation of SMAD proteins through phosphorylation, regulation of target genes expression in association with DNA-binding partners and regulation of SMAD activity and degradation. Disruption of the TGF-β pathway has been implicated in many human diseases, including solid and hematopoietic tumors. As a potent inhibitor of cell proliferation, TGF-β acts as a tumor suppressor; however in tumor cells, TGF-β looses anti-proliferative response and become an oncogenic factor. This article reviews current understanding of TGF-β signaling and different mechanisms that lead to its impairment in various solid tumors and hematological malignancies.

Proteasome inhibitors – molecular basis and current perspectives in multiple myeloma

Inhibition of proteasome, a proteolytic complex responsible for the degradation of ubiquitinated proteins, has emerged as a powerful strategy for treatment of multiple myeloma (MM), a plasma cell malignancy. First‐in‐class agent, bortezomib, has demonstrated great positive therapeutic efficacy in MM, both in pre‐clinical and in clinical studies. However, despite its high efficiency, a large proportion of patients do not achieve sufficient clinical response. Therefore, the development of a second‐generation of proteasome inhibitors (PIs) with improved pharmacological properties was needed. Recently, several of these new agents have been introduced into clinics including carfilzomib, marizomib and ixazomib. Further, new orally administered second‐generation PI oprozomib is being investigated. This review provides an overview of main mechanisms of action of PIs in MM, focusing on the ongoing development and progress of novel anti‐proteasome therapeutics.

Serum miR-29a as a marker of multiple myeloma

MicroRNA (miRNA) are small non-coding RNA playing a significant role in pathogenesis of multiple myeloma (MM). We have identified a specific serum miRNA profile in MM patients (pts) and correlated it with clinical parameters. Methods. 133 serum samples: 103 (51M/52F) from newly diagnosed MM pts and 30 (14M/16F) from healthy donors (HD) were tested. A screening of 667 serum miRNA was performed on 4 MM and 4 HD with TaqMan Low Density Arrays (TLDA). Expression of differentially expressed miRNA was validated by RT-PCR. Area under curve (AUC), specificity, sensitivity and correlation with clinical parameters was analyzed.Results. Based on TLDA, 14 miRNA were differentially expressed between MM and HD (p<0.05). Out of them, five miRNA were validated by RT-PCR: miR-744 (p<0.0004), miR-130a (p<0.0002), let 7d (p<0.0001) and let-7e (p<0.0001) were significantly downregulated and miR-34a (p<0.0001) was significantly upregulated. ROC analysis showed highest sensitivity (80.6%), specificity (86.7%) and AUC (0.898) for a combination of miR-34a and let-7d. Positive correlation was observed between low levels of miR-744, let-7d and let-7e and levels of hemoglobin, thrombocytes and albumin (all p=0.0001), negative correlation between low miRNA levels and levels of creatinine and beta2 microglobulin was found (all p<0.0001). Expression of miR-744, let-7d and let-7e showed an inverse correlation with ISS stage (all p<0.0001).Conclusion. Our study shows that miRNA may be a promising biomarker for MM pts.

Mechanism of immunomodulatory drugs in multiple myeloma

Multiple myeloma is the second most common hematological cancer in the world. It is characterized by accumulation of malignant plasma cells in the bone marrow, osteolytic lesions and monoclonal immunoglobulins in blood/urine. With the introduction of immunomodulatory drugs into the treatment protocol, the outcome of multiple myeloma patients has dramatically improved with more than 30% of patients surviving for 10 years thus shifting multiple myeloma to a treatable condition.

Circulating Serum MicroRNA-130a as a Novel Putative Marker of Extramedullary Myeloma.

Poor outcome of extramedullary disease in multiple myeloma patients and lack of outcome predictors prompt continued search for new markers of the disease. In this report, we show circulating microRNA distinguishing multiple myeloma patients with extramedullary disease from myeloma patients without such manifestation and from healthy donors. MicroRNA-130a was identified by TaqMan Low Density Arrays and verified by quantitative PCR on 144 serum samples (59 multiple myeloma, 55 myeloma with extramedullary disease, 30 healthy donors) in test and validation cohorts as being down-regulated in myeloma patients with extramedullary disease. Circulating microRNA-130a distinguished myeloma patients with extramedullary disease from healthy donors with specificity of 90.0% and sensitivity of 77.1%, patients with extramedullary disease from newly diagnosed multiple myeloma patients with specificity of 77.1% and sensitivity of 34.3% in the test cohort and with specificity of 91.7% and sensitivity of 30.0% in the validation cohort of patients. Circulating microRNA-130a in patients with extramedullary myeloma was associated with bone marrow plasma cells infiltration. Further, microRNA-130a was decreased in bone marrow plasma cells obtained from patients with extramedullary myeloma in comparison to bone marrow plasma cells of myeloma patients without such manifestation, but it was increased in tumor site plasma cells of patients with extramedullary disease compared to bone marrow plasma cells of such patients (p<0.0001). Together, our data suggest connection between lower level of microRNA-130a and extramedullary disease and prompt further work to evaluate this miRNA as a marker of extramedullary disease in multiple myeloma.

Cell-free DNA — Minimally invasive marker of hematological malignancies

Although tumor cells are the most reliable source of tumor DNA, biopsy of the tumor is an invasive procedure that should be avoided in some cases. The main limitation of any biopsy is sampling of one tumor site, which may not represent all malignant clones due to the heterogeneity of the tumor. These clones respond to treatment differently and thus directly influence survival of the patient. Circulating cell‐free DNA (cfDNA) is released from multiple tumor sites, reflects overall heterogeneity of the tumor, and correlates with its progression. Detection of tumor‐specific genetic and epigenetic aberrations in cfDNA could have a direct impact on molecular diagnosis, prognosis, follow‐up of disease, monitoring of minimal residual disease, and response to treatment. While most cfDNA data are still experimental, they are very promising. This review focuses on cfDNA in hematological malignancies.

Cytogenetics in multiple myeloma patients progressing into extramedullary disease

Extramedullary disease in multiple myeloma patients is an uncommon event occurring either at the time of diagnosis, or during disease progression/relapse. This manifestation is frequently associated with poor outcome and resistance to treatment. We evaluated chromosomal alterations of plasma cells of multiple myeloma patients with extramedullary relapse, either in the bone marrow (BM) or at extramedullary sites, and in previous BM collection by interphase fluorescence in situ hybridization.

The miR-29 family in hematological malignancies.

BACKGROUND MicroRNAs are short non-coding regulators of gene expression. The human miR-29 family consists of three members: miR-29a, miR-29b and miR-29c. Members of this family were found to be aberrantly expressed in various types of tumors, including hematological malignancies. This family was described to have both oncogenic and tumor suppressor features influencing various pathological processes, such as tumor growth and apoptosis. This review summarizes current knowledge about the miR-29 family in selected hematological malignancies. CONCLUSION Recent research of miR-29 family in hematological malignancies has proven its oncogenic as well as tumor suppressive potential. Nevertheless, the level of current evidence is not sufficient, and data remain inconclusive.

Circulating microRNA as Biomarkers in Hematological Malignancies

Hematopoiesis is a highly regulated process controlled by a complex network of molecular mechanisms that simultaneously regulate differentiation, proliferation, and apoptosis of hematopoietic stem cells. Aberrant microRNA (miRNA) expression could affect normal hematopoiesis, leading to the development of hematological malignancies. Hematologic cancers, which are caused by malignant transformation of cells of the bone marrow and the lymphatic system, are usually divided into three major groups: leukemias, lymphomas, and monoclonal gammopathies. Hematologic malignancies are highly aggressive diseases with high morbidity and mortality. For these reasons, early and easily obtainable markers for diagnosis, risk stratification, and follow-up are essential for improvement of outcome and survival of these patients. Recent studies have provided new insights about the diagnostic value of expression patterns of miRNAs in serum/plasma in these diseases. While the use of circulating miRNAs is only at the experimental level, it appears to have a great potential. This chapter deals with the use of circulating miRNAs as minimally invasive biomarkers in hematologic malignancies.

Circulating exosomal long noncoding RNA PRINS-First findings in monoclonal gammopathies.

Multiple myeloma is the second most common hematological malignancy characterized by focal lesions of malignant plasma cells in the bone marrow. These lesions contain subclones that directly influence survival of patients. Bone marrow biopsies are single‐site biopsies and thus cannot contain all information about the tumor. In contrast, liquid biopsies analyze circulating cells and molecules that are secreted from all sites of the tumor. Long noncoding RNA molecules are one class of these molecules. We performed a two‐phase biomarker study investigating lncRNA expression profiles in exosomes of peripheral blood serum of newly diagnosed multiple myeloma (MM) patients, monoclonal gammopathy of undetermined significance (MGUS) patients in comparison with healthy donors (HD). Surprisingly, this analysis revealed dysregulation of only one exosomal lncRNA PRINS in MM vs HD. Overall, MM and MGUS patients were distinguished from HD with sensitivity of 84.9% and specificity of 83.3%. Our study suggests a possible diagnostic role for exosomal lncRNA PRINS in monoclonal gammopathies patients.