Transforming growth factor β (TGF-β) superfamily consists of numerous cytokins that regulate various cellular processes. TGF-β, the prototype of the family, signals through its cell surface serine/threonin kinase receptors and besides its role in cell differentiation, migration, adhesion etc. it is also able to induce epithelial-mesenchymal (EMT) transition via both Smad- pathway and MAPK- pathway. Among the different types of epithelial-mesenchymal transition, type II that is described to be associated with wound healing, tissue regeneration, organ fibrosis and is induced upon inflammatory stimuli. It can be triggered by secretion of growth factors such as TGF-β, EGF. Different endocytic routes are used for the internalization of TGF-β ligand and its receptors and these pathways can control the activity of downstream events. Internalization via clathrin-coated vesicles promotes the signaling while the caveola-mediated endocytosis plays important role in the termination of the events, although the steps of the latter event are less clear. The early endosome is considered a clue compartment in promoting the signaling. Recently published data suggest that the early endosome plays crucial role in the termination of the TGFβ signaling as well. It is not only maintain a special environment for the effective signaling but can direct the internalized cargos towards degradative pathways (multivesicular bodies, lysosomes).

BackgroundRhabdomyosarcoma (RMS) is a malignant tumor of mesenchymal origin and comprises the largest category of soft-tissue sarcomas both in children and adolescents. From a pediatric oncology point of view, RMS has traditionally been classified into alveolar (ARMS) and embryonal (ERMS) subtypes. The anatomical localization of the tumor may vary, but commonly involve the head/neck regions, male and female urogenital tract or the trunk and extremities.Case presentationHere, we report two challenging cases involving 17- and 9-years-olds males where diffuse and multiplex bone lesions suggested either a hematological disease or a primary bone tumor (mesenchymal chondrosarcoma). Biopsies, proved a massive infiltration of the bone marrow cavity with rhabdomyosarcoma. In both cases, the ARMS subtype was confirmed using FOXO1 break-apart probes (FISH). Radiological examination could not identify primary soft tissue component in any localization at the time of diagnosis in either cases.ConclusionsPrimary alveolar rhabdomyosarcoma of the bone as a subtype of ARMS, seems to be a distinct clinico-pathological entity with challenging diagnostic difficulties and different, yet better, biological behavior in comparison to soft tissue ARMS. However, it is difficult to be characterized or predict its prognosis and long-term survival as only sporadic cases (four) were reported so far.

Peritoneal cell suspension is composed of heterogeneous cell population. Macrophages are the most numerous cells among them. They can originate from different sources and can be resident, exudate and elicited. When we used Freund's adjuvant to elicit peritoneal macrophages, cells having large amount of caveolae on their plasma membrane appeared in the peritoneal wash. The number of these caveolae-rich cells increased by the time of the Freund's adjuvant treatment. Although their morphology was different form from the common macrophages, they were labelled with pan-macrophage antibodies. As the origin of these cells is unknown in this work, we tried to find out where they can originate from. Our interest turned towards the mesothelial cells. We found that the adjuvant treatment resulted in significant morphological changes in these cells and stimulate them to leave the surface of the mesentery. By the time of the adjuvant treatment, the macrophage markers expression increased in the mesothelial cells and more cells were found to detach from the mesentery. These results strongly suggest that under special stimuli mesothelial cells can leave the mesentery and differentiate into phagocytotic (macrophage-like) cells. These data raises the idea that mesothelial cells might not entirely differentiated and represent a multipotential cell lineage. To study whether this is the case we used anti-nestin antibody, which is a specific marker for multifunctional, multi-lineage progenitor cells. Mesothelial cells showed strong labelling with this antibody indicating that these cells really represent a 'young', not entirely differentiated cell population.

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Intraperitoneal injection of Freund's adjuvant induces acute peritonitis. By the time of the Freund's adjuvant treatment the flat, simple squamous epithelial cells became rounded, cuboidal shaped, many of them have lost their connection with the neighbouring cells and detached from the basement membrane. The macrophage markers' (ED1, OX43 and CD68) expression also increased in the mesothelial cells and more mesothelin and anti-ED1 double-labelled cells were found freely present close to the surface. The cytokeratin expression of the mesothelial cells has gradually decreased. At the 5th day of the inflammation practically there was no cytokeratin labelling present in the mesothelial cells and the mesothelin expression has significantly decreased. Parallel to this mesothelial cells started to express vimentin, a characteristic mesenchymal intermediate filament protein indicating that they gradually lost their epithelial character and gained mesenchymal phenotype. These results strongly suggest that under the effect of Freund's adjuvant treatment (inflammation) mesothelial cells can undergo epithelial-to-mesenchymal transition and differentiate into phagocytotic (macrophage-like) cells. Studying the caveolae/caveolin-1 on the plasma membrane of mesothelial cells we found that the Freund's adjuvant treatment has changed the cellular distribution of caveolin-1: as the inflammation progressed strong caveolin-1 labelling was found inside of the cytoplasm (in perinuclear localization) indicating that inflammation induced the caveolae internalization. These results indicate that caveolae/caveolin-1 might play important regulatory role in signal transduction leading to trasdifferentiation.

BackgroundAlthough membrane-associated estrogen receptors (mERs) have been known to play important role in steroid-induced signal transmission, we still know little about their function in the estrogen-induced proliferation of breast cancer cells.MethodsIn our current work we tried to separate membrane-initiated estrogen receptor signaling from the overall estrogenic effect in MCF-7 breast carcinoma cells. Re-analyzing expression data from multiple microarray experiments, we selected a set of key regulatory genes involved in proliferation regulation and estrogen signaling to monitor estrogen-induced transcription changes. We then compared these expression changes after 17β-estradiol and a membrane receptor selective estrogen–BSA treatment using quantitative real-time PCR. In order to follow receptor trafficking we used light and electron microscopy.ResultsOur quantitative real-time PCR results confirmed that the selective membrane receptor agonist, estrogen–BSA induces similarly pronounced expression changes regarding these genes as 17β-estradiol. Morphological study revealed that the membrane-bound form of classical estrogen receptor alpha is internalized after ligand binding via dynamin-dependent, caveola-mediated endocytosis. Inhibition of this internalization with dynamin inhibitor, dynasore practically abolished the regulatory effect of E2-BSA, suggesting that interaction and internalization with the scaffold protein is necessary for effective signaling.ConclusionsThe physiological role of plasma membrane estrogen receptor alpha is intensively studied, yet there are still several aspects of it to be resolved. The dynamin-dependent, ligand-mediated internalization of mERs seems to play an important role in estrogen signaling. Our results may serve as another example of how membrane initiated estrogen signaling and nuclear receptor initiated signaling overlap and form an intertwined system. Electronic supplementary materialThe online version of this article (10.1186/s40001-018-0328-7) contains supplementary material, which is available to authorized users.

The presence of GPER and its simultaneous expression with ERβ can serve as a new prognostic indicator in a significant subpopulation of melanoma patients.

Chordoma is a rare, malignant bone tumour showing notochordal differentiation and expressing brachyury on immunohistochemistry, occurring along the spinal axis, from the skull base to coccyx. Rare extra-axial cases have been described in literature 1 .