Experimental and early clinical data suggest that, due to several unique properties, mesenchymal stem cells (MSCs) may be more effective than other cell types for diseases that are difficult to treat or untreatable. Owing to their ease of isolation and culture as well as their secretory and immunomodulatory abilities, MSCs are the most promising option in the field of cell-based therapies. Although MSCs from various sources share several common characteristics, they also exhibit several important differences. These variations may reflect, in part, specific regional properties of the niches from which the cells originate. Moreover, morphological and functional features of MSCs are susceptible to variations across isolation protocols and cell culture conditions. These observations suggest that careful preparation of manufacturing protocols will be necessary for the most efficient use of MSCs in future clinical trials. A typical human myocardial infarct involves the loss of approximately 1 billion cardiomyocytes and 2-3 billion other (mostly endothelial) myocardial cells, leading (despite maximized medical therapy) to a significant negative impact on the length and quality of life. Despite more than a decade of intensive research, search for the "best" (safe and maximally effective) cell type to drive myocardial regeneration continues. In this review, we summarize information about the most important features of MSCs and recent discoveries in the field of MSCs research, and describe current data from preclinical and early clinical studies on the use of MSCs in cardiovascular regeneration. STEM CELLS TRANSLATIONAL MEDICINE 2017;6:1859-1867 SIGNIFICANCE STATEMENTThis concise review discusses present and future applications of mesenchymal stem cells (MSC) in therapy of cardiovascular disorders. It summarizes both preclinical and clinical trials conducted in this area with strong emphasis on mechanisms of MSCs action. Its main impact lies in comprehensive summary of ongoing and finished studies.

Rhabdomyosarcoma (RMS) is a mesenchymal tumor of soft tissue in children that originates from a myogenic differentiation defect. Expression of SNAIL transcription factor is elevated in the alveolar subtype of RMS (ARMS), characterized by a low myogenic differentiation status and high aggressiveness. In RMS patients SNAIL level increases with higher stage. Moreover, SNAIL level negatively correlates with MYF5 expression. The differentiation of human ARMS cells diminishes SNAIL level. SNAIL silencing in ARMS cells inhibits proliferation and induces differentiation in vitro, and thereby completely abolishes the growth of human ARMS xenotransplants in vivo. SNAIL silencing induces myogenic differentiation by upregulation of myogenic factors and muscle-specific microRNAs, such as miR-206. SNAIL binds to the MYF5 promoter suppressing its expression. SNAIL displaces MYOD from E-box sequences (CANNTG) that are associated with genes expressed during differentiation and G/C rich in their central dinucleotides. SNAIL silencing allows the re-expression of MYF5 and canonical MYOD binding, promoting ARMS cell myogenic differentiation. In differentiating ARMS cells SNAIL forms repressive complex with histone deacetylates 1 and 2 (HDAC1/2) and regulates their expression. Accordingly, in human myoblasts SNAIL silencing induces differentiation by upregulation of myogenic factors. Our data clearly point to SNAIL as a key regulator of myogenic differentiation and a new promising target for future ARMS therapies.

There is a need among patients suffering from drug‐resistant epilepsy (DRE) for more efficient and less toxic treatments. The objective of the present study was to assess the safety, feasibility, and potential efficacy of autologous bone marrow cell transplantation in pediatric patients with DRE. Two females and two males (11 months to 6 years) were enrolled and underwent a combined therapy consisting of autologous bone marrow nucleated cells (BMNCs) transplantation (intrathecal: 0.5 × 109; intravenous: 0.38 × 109–1.72 × 109) followed by four rounds of intrathecal bone marrow mesenchymal stem cells (BMMSCs) transplantation (18.5 × 106–40 × 106) every 3 months. The BMMSCs used were a unique population derived from CD271‐positive cells. The neurological evaluation included magnetic resonance imaging, electroencephalography (EEG), and cognitive development assessment. The characteristics of BMMSCs were evaluated. Four intravenous and 20 intrathecal transplantations into the cerebrospinal fluid were performed. There were no adverse events, and the therapy was safe and feasible over 2 years of follow‐up. The therapy resulted in neurological and cognitive improvement in all patients, including a reduction in the number of epileptic seizures (from 10 per day to 1 per week) and an absence of status epilepticus episodes (from 4 per week to 0 per week). The number of discharges on the EEG evaluation was decreased, and cognitive improvement was noted with respect to reactions to light and sound, emotions, and motor function. An analysis of the BMMSCs' characteristics revealed the expression of neurotrophic, proangiogenic, and tissue remodeling factors, and the immunomodulatory potential. Our results demonstrate the safety and feasibility of BMNCs and BMMSCs transplantations and the considerable neurological and cognitive improvement in children with DRE. stem cells translational medicine 2018;7:20–33

Neurological disorders are a massive challenge for modern medicine. Apart from the fact that this group of diseases is the second leading cause of death worldwide, the majority of patients have no access to any possible effective and standardized treatment after being diagnosed, leaving them and their families helpless. This is the reason why such

The properties of mesenchymal stem cells (MSCs), especially their self-renewal and ability to differentiate into different cell lines, are widely discussed. Considering the fact that MSCs isolated from perinatal tissues reveal higher differentiation capacity than most adult MSCs, we examined mesenchymal stem cells isolated from Wharton’s jelly of umbilical cord (WJ-MSCs) in terms of pluripotency markers expression. Our studies showed that WJ-MSCs express some pluripotency markers—such as NANOG, OCT-4, and SSEA-4—but in comparison to iPS cells expression level is significantly lower. The level of expression can be raised under hypoxic conditions. Despite their high proliferation potential and ability to differentiate into different cells type, WJ-MSCs do not form tumors in vivo, the major caveat of iPS cells. Owing to their biological properties, high plasticity, proliferation capacity, and ease of isolation and culture, WJ-MSCs are turning out to be a promising tool of modern regenerative medicine.

Rhabdomyosarcoma is the most common soft tissue sarcoma in childhood and young adulthood. Conventional treatment consisting of surgery, chemotherapy and radiotherapy can be insufficient, as long-term survival chances decrease dramatically when cancer recurrence occurs. Due to this fact, efficient treatment of this cancer is still a demanding issue, thus, novel and innovative therapies have to be considered as a part of combined treatment. In the present study, we present effective suicide gene therapy of rhabdomyosarcoma cell line Rh30 involving herpes simplex thymidine kinase (HSV-TK) and ganciclovir (GCV). Transduction of rhabdomyosarcoma cells using lentiviral vectors allowed efficient introduction of HSV-TK gene. In this study we proved high susceptibility of modified cells to ganciclovir resulting in eradication of cancer cells both in vitro and in vivo. Our data revealed strong gap junctional intercellular communication in examined cell line responsible for elimination of unmodified cells by bystander effect, even if HSV-TK-expressing cells comprise only 20% of cultured cells. Moreover, investigated approach is also efficient in vivo, where complete remission of tumors upon only 14 days of systemic administration of GCV can be observed. Obtained results suggest that HSV-TK suicide gene therapy is very promising concept in future clinical studies concerning rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is a soft tissue mesenchymal tumor that affects mostly children and adolescents. It originates from the impaired myogenic differentiation of stem cells or early progenitors. SNAIL, a transcription factor that regulates epithelial-to-mesenchymal transition in tumors of epithelial origin, is also a key regulator of RMS growth, progression, and myogenic differentiation. Here, we demonstrate that the SNAIL-dependent microRNAs (miRNAs) miR-28-3p and miR-193a-5p are crucial regulators of RMS growth, differentiation, and progression. miR-28-3p and miR-193a-5p diminished proliferation and arrested RMS cells in G0/G1 phase in vitro . They induced the myogenic differentiation of both RMS cells and human myoblasts by upregulating myogenic factors. Furthermore, miR-28-3p and miR-193a-5p inhibited migration in a scratch assay, adhesion to endothelial cells, chemotaxis, and invasion toward SDF-1 and HGF and regulated angiogenic capabilities of the cells. Overexpression of miR-28-3p and miR-193a-5p induced formation of fibrotic structures and abnormal blood vessels in RMS xenografts in immunodeficient mice in vivo . Simultaneous overexpression of both miRNAs diminished tumor growth after subcutaneous implantation and inhibited the engraftment of RMS cells into bone marrow after intravenous injection in vivo . To conclude, we discovered novel SNAIL-dependent miRNAs that may become new therapeutic targets in RMS in the future.

Targeting of the TRAIL‐DR4/5 pathway was proposed as a promising approach for specific induction of apoptosis in cancer cells. Clinical trials, however, showed inadequate efficiency of TRAIL as a monotherapy. It is a widely held view that the application of multifunctional molecules or combination therapy may lead to substantial improvement. Here, we demonstrate the effectiveness and safety of a novel chimeric protein, AD‐O51.4, which is a TRAIL equipped with positively charged VEGFA‐derived effector peptides. The study was performed in multiple cancer cell line‐ and patient‐derived xenografts. A pharmacokinetic profile was established in monkeys. AD‐O51.4 strongly inhibits tumor growth, even leading to complete long‐term tumor remission. Neither mice nor monkeys treated with AD‐O51.4 demonstrate symptoms of drug toxicity. AD‐O51.4 exhibits a satisfactory half‐life in plasma and accumulates preferentially in tumors. The cellular mechanism of AD‐O51.4 activity involves both cytotoxic effects in tumor cells and antiangiogenic effects on the endothelium. The presence of DRs in cancer cells is crucial for AD‐O51.4‐driven apoptosis execution. The TRAIL component of the fusion molecule serves as an apoptosis inducer and a cellular anchor for the effector peptides in TRAIL‐sensitive and TRAIL‐resistant cancer cells, respectively. The FADD‐dependent pathway, however, seems to be not indispensable in death signal transduction; thus, AD‐O51.4 is capable of bypassing the refractoriness of TRAIL. AD‐O51.4‐driven cell death, which exceeds TRAIL activity, is achieved due to the N‐terminally fused polypeptide, containing VEGFA‐derived effector peptides. The high anticancer efficiency of AD‐O51.4 combined with its safety has led to the entry of AD‐O51.4 into toxicological studies.