SNAIL is a key regulator of alveolar rhabdomyosarcoma tumor growth and differentiation through repression of MYF5 and MYOD function.

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.

Mutation c.256_257delAA in RAG1 Gene in Polish Children with Severe Combined Immunodeficiency: Diversity of Clinical Manifestations.

Mutations in RAG1 gene may result in different types of severe combined immunodeficiencies. In this study, we compare clinical symptoms and laboratory findings in four children with identical mutation in RAG1 gene. All of analyzed patients presented symptoms of severe combined immunodeficiencies associated or not with Omenn syndrome (OS) features. In our patients two different types of variants in RAG1 gene were detected. The first of the mutation was the deletion of AA dinucleotide at position c.256_257 (p.Lys86ValfsTer33), the second gene variant was substitution c.2867T>C (p.Ile956Thr). In Patient 1 we detected that compound heterozygous mutations involved both of the mentioned variants. Whereas, in Patients 2, 3 and 4, we confirmed the presence of the dinucleotide deletion but in a homozygous state. In all described patients, sequence analysis of RAG2 gene did not reveal any nucleotide changes. Our data show that mutation c.256_257delAA in RAG1 gene seems to occur quite frequently in the polish patients with severe combined immunodeficiency and may result in classical OS as well as in severe combined immunodeficiency without clinical and laboratory features of OS when occurred in homozygous state. The same mutation but in heterozygous state, in combination with other mutation in RAG1 gene, may result in incomplete OS.

Regulation of transcription in cancer.

The purpose of this article is to provide an overview on the regulation of transcription in cancer cells. We describe here standard mechanisms of transcription in eukaryotic cells, an influence of common promoter polymorphisms contributing to malignant progression and DNA methylation as significant aspect of gene regulation. We also described transcription factors mechanism of action, and how their alteration can result in cancer.

The loss of the CD16 B73.1/Leu11c epitope occurring in some primary immunodeficiency diseases is not associated with the FcgammaRIIIa-48L/R/H polymorphism.

The loss of the CD16a, Fc receptor for IgG type III, (FcgammaRIIIa) B73.1/Leu11c binding epitope, detected by the monoclonal antibody (mAb) used in routine enumeration of NK cells or monocytes, has been observed in children with recurrent viral infections. It has also been linked with the change of leucine (L) to histidine (H) or arginine (R) at amino acid position 48 (FcgammaRIIIa-48L/R/H) in the CD16a receptor. The reactivity of the anti-CD16a clone B73.1/Leu11c mAb with monocytes and NK cells was examined in patients with primary immunodeficiencies (n=167), gastrointestinal malignancies (n=91) and healthy subjects (n=88). Cells of only 12 children, 11 with diagnosed primary immunodeficiency and one with recurrent bacterial infections were not reactive with B73.1/Leu11c mAb. In contrast to previous findings, no linkage between the loss of B73.1/Leu11c binding epitope and herpes virus infections was observed. Furthermore, the sequence analysis of the FcgammaRIIIa gene performed in these 12 patients and 11 healthy subjects revealed that all of them had FcgammaRIIIa-48L/L genotype. Thus, the loss of B73.1/Leu11c binding epitope was not associated with the FcgammaRIIIa-48 polymorphism. The commonly described FcgammaRIIIa-158 polymorphism was determined to be 158V/V in 11 patients and 5 healthy subjects. Moreover, no linkage between FcgammaRIIIa-48L/L and -158F/F genotypes was observed. It is suggested that the loss of the B73.1/Leu11c binding epitope is connected with primary immunodeficiency disorders, but not associated with the FcgammaRIIIa-48 polymorphism.

Role of I-TAC-binding receptors CXCR3 and CXCR7 in proliferation, activation of intracellular signaling pathways and migration of various tumor cell lines.

Chemokines and its receptors stimulate tumor growth, migration and invasion. In this study we evaluated the expression and function of CXCR3 and CXCR7 receptors in cervical carcinoma, rhabdomyosarcoma and glioblastoma cell lines. We found that both receptors were expressed at different degree by tumor cells. CXCR7 was expressed at both mRNA and protein level by all tumor cell lines. The expression of CXCR7 differed between rhabdomyosarcoma subtypes. The receptor was highly expressed in alveolar rhabdomyosarcoma and the expression was low in embryonal rhabdomyosarcoma. The expression of CXCR3 was low in majority of the tumor cell lines. Upon I-TAC stimulation AKT and MAPK kinases were activated. However, the activation of growth promoting pathways did not increased the proliferation rate of tumor cells. Since chemokines stimulate the migration of various cell types the ability of I-TAC to stimulate migration of tumor cells were studied. We did not observe the migration of tumor cells toward I-TAC gradient alone. However, at the low dose, I-TAC sensitized tumor cells toward SDF-1beta gradient and synergized with SDF-1beta in activation of intracellular pathways. Our data suggest an important role of I-TAC and its receptors in biology of solid tumors and we postulate that I-TAC-binding receptors might be used as the potential targets for antitumor therapy.

Familial occurrence of warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome.

INTRODUCTION: Warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome is a rare immunodeficiency disorder with an autosomal-dominant pattern of inheritance and low fatality rate but significant lifelong morbidity. MATERIALS AND METHODS: A 27-year-old mother of two children has been suffering from severe neutropenia and recurrent infections with the diagnosis of sporadic WHIM syndrome established by sequencing the CXCR4 gene and the finding of a heterozygous 1000 C-->T nonsense mutation in the second CXCR4 exon. The first child was an apparently healthy boy delivered at full term. Umbilical cord blood cells were obtained for genetic analysis. Peripheral blood cells were also analyzed at 8 months of life. Both analyses revealed the same mutation as that of his mother. The child was in a good condition, manifesting neutropenia without infections until 11 months of life. He subsequently developed pneumonia requiring a more aggressive treatment. After that, the regular substitution of immunoglobulins (IVIGs) and G-CSF has been preventing serious infections. Six months ago the second boy was delivered who also demonstrated neutropenia without severe infections. Genetic studies using cord blood and also peripheral blood cells in the fourth month showed an identical mutation of the CXCR4 gene as in his mother. Moreover, the mother and her first son demonstrated monocytopenia. RESULTS: The results indicate that genetic defects connected with WHIM syndrome may influence not only the granulocyte, but also the monocytic lineage. Moreover, a perinatal diagnosis of WHIM syndrome made by sequencing the CXCR4 gene should be performed in cases where either parent is known to be affected with this disease. CONCLUSIONS: This would facilitate an earlier detection of the deficiency in children, thereby allowing a more comprehensive follow-up and administration of appropriate therapy.