Rhabdomyosarcoma (RMS) is the most common type of pediatric soft tissue sarcoma. The MET receptor has an important role in the biology of RMS, and its overexpression and hyperactivation correlate with the metastatic ability of RMS. Consequently, interfering with MET expression or functionality may constitute a sound strategy for reducing the progression and metastatic potential of RMS. Our study reveals that downregulation of the MET receptor leads to changes in the morphology of ARMS cell in vivo. Tumors acquire a spindle shape that is characteristic of muscle fibers. Inhibition of MET expression or function leads to (i) a decreased expression of the early myogenic marker MyoD, (ii) a decreased ability of ARMS cells to metastasize to bone marrow cavities, (iii) downregulation of CXCR4 receptor expression and (iv) a decreased migration of MET-depleted cells towards gradients of HGF and SDF-1. Finally, we demonstrate that in vitro differentiation of alveolar RMS cells decreases their metastatic behavior by reducing both the expression of the MET and CXCR4 receptors and their migratory response to HGF and SDF-1. These findings suggest that blockers of MET receptor function and inducers of RMS cells differentiation may be clinically useful for reducing the aggressiveness and metastatic potential of RMS and may have significant implications for its treatment.

Rhabdomyosarcoma (RMS) is a soft tissue sarcoma usually diagnosed in children. In advanced and metastatic stages the prognosis is often poor. RMS cell lines were used for evaluation of the role of MET receptor inhibition on chemotaxis and invasion. In vivo studies were performed using NOD-SCID xenograft model. This study shows that blocking of MET expression has strong influence on metastatic behavior of RMS. MET negative cells possess a reduced potential to migrate and to invade. Downregulation of MET suppressed the ability of RMS cells to populate bone marrow. Inhibition of MET negative tumor cells engraftment into bone marrow was observed. MET negative tumors were also two to four times smaller than their wild type counterparts. Since MET receptor plays a very important role in facilitating metastasis of RMS cells, blocking of HGF-MET axis might be considered as a therapeutic option for RMS patients, at more advanced and metastatic stages.

Background The prevalence of autoimmune thyroiditis (AIT) and papillary thyroid carcinoma (PTC) is rising in children and adolescents, and the coincidence of AIT and PTC is as high as 6.3–43%.ObjectiveTo investigate the ultrasound manifestation of AIT in relation to PTC development in paediatric patients.Patients179 paediatric patients (133 females), mean (SD) age: 13.9 (3.03) years diagnosed with AIT and referred for ultrasound evaluation. Eight patients were diagnosed with PTC (6 females). MethodsRetrospective analysis of thyroid ultrasound scans of patients diagnosed with AIT. Thyroid and autoimmune status was assessed based on TSH, fT4, fT3 and increased aTPO and/or aTG and/or TRAB levels. In patients with PTC, total thyroidectomy was performed.ResultsAnalysis of thyroid US scans revealed that the following five ultrasound variants of AIT were observed in 179 patients: the most common in 35.2%—diffuse thyroiditis with hypoechogenic background and normoechogenic parenchyma, in 30.2%—diffuse thyroiditis with irregular background, in 18.9% nodular variant with normoechogenic background, in 11.7%—micronodulations and in 3.9%—diffuse hypoechogenic background. Eight cases of PTC were diagnosed in nodular variant of AIT with normoechogenic irregular background.ConclusionPatients with AIT and nodular variant with normoechogenic irregular background of the thyroid gland on US scans are in the risk group of developing PTC and should be followed up with regular neck US assessment.

Metronomic agents reduce the effective doses and adverse effects of cytostatics in cancer chemotherapy. Therefore, they can enhance the treatment efficiency of drug-resistant cancers. Cytostatic and anti-angiogenic effects of fenofibrate (FF) suggest that it can be used for the metronomic chemotherapy of drug-resistant prostate tumors. To estimate the effect of FF on the drug-resistance of prostate cancer cells, we compared the reactions of naïve and drug-resistant cells to the combined treatment with docetaxel (DCX)/mitoxantrone (MTX) and FF. FF sensitized drug-resistant DU145 and PC3 cells to DCX and MTX, as illustrated by their reduced viability and invasive potential observed in the presence of DCX/MTX and FF. The synergy of the cytostatic activities of both agents was accompanied by the inactivation of P-gp-dependent efflux, dysfunction of the microtubular system, and induction of polyploidy in DCX-resistant cells. Chemical inhibition of PPARα- and reactive oxygen species (ROS)-dependent pathways by GW6471 and N-acetyl-L-cysteine, respectively, had no effect on cell sensitivity to combined DCX/FF treatment. Instead, we observed the signs of adenosine triphosphate (ATP) deficit and autophagy in DCX/FF-treated drug-resistant cells. Furthermore, the cells that had been permanently propagated under DCX- and DCX/FF-induced stress did not acquire DCX/FF-resistance. Instead, relatively slow proliferation of DCX-resistant cells was efficiently inhibited by FF. Collectively, our observations show that FF reduces the effective doses of DCX by interfering with the drug resistance and energy metabolism of prostate cancer cells. Concomitantly, it impairs the chemotherapy-induced microevolution and expansion of DCX/FF-resistant cells. Therefore, FF can be applied as a metronomic agent to enhance the efficiency of palliative chemotherapy of prostate cancer.

Cervical cancer is one of the leading causes of death among women suffering from tumors. Current treatment options are insufficient. Here, we investigated the MET receptor as a potential molecular target in advanced cervical cancer. Downregulation of MET receptor expression via RNA interference in different cervical carcinoma cell lines dramatically decreased tumor growth and forced tumor differentiation in vivo. MET receptor silencing also led to a dramatic decrease in cell size and a decrease in proliferation rate under normal and stress conditions. MET receptor downregulation also resulted in decreased cyclin D1 and c-myc levels but did not increase apoptosis. Subsequent experiments showed that downregulation of the MET receptor decreased the expression of a key regulator of the epithelial-to-mesenchymal transition, SLUG. and increased the expression of E-cadherin, a hallmark of the epithelial phenotype. Moreover, MET downregulation impairs expression and signaling of CXCR4 receptor, responsible for invasive phenotype.Taken together, our results strongly suggest that the MET receptor influences the oncogenic properties of cervical carcinoma cells in vitro and in vivo. These findings highlight a unique role of the MET receptor in cervical carcinoma cells and indicate the MET receptor as a potential therapeutic target for advanced cervical carcinoma.

Purpose To present the outcomes of ultrasound (US) follow-ups in children with autoimmune thyroid disease who did not have a thyroid nodule on admission but developed papillary thyroid carcinoma (PTC) and to characterize the parenchymal changes in the thyroid gland prior to the development of PTC. Methods A retrospective thyroid US scan review of 327 patients diagnosed with AIT was performed. Forty patients (40/327, 12.2%) presented nodular AIT variant with a normoechogenic background. Eleven patients (11/327, 3.4%, 11/40, 27.5%) presenting this variant were diagnosed with PTC (nine females-mean age 15.3 years; two males aged 11 and 13 years). In five of 11 patients, the suspicious nodule that was later confirmed to be PTC was detected on the initial US at presentation. For the remaining six females (6/11) who developed PTC during the follow-up, we retrospectively analysed their US thyroid scans and these patients were selected for analysis in this study. Results On admission, the US evaluation revealed an enlarged normoechogenic thyroid gland in three patients and a hypoechogenic thyroid gland with fibrosis as indicated by irregular, chaotic hyperechogenic layers in three patients. No thyroid nodules were identified. Ultrasound monitoring revealed increasing echogenicity of the thyroid parenchyma during the follow-up. PTC developed in a mean time of 4.6 years (1 9/12-7 4/12 years) since referral to the outpatient thyroid clinic and 2.9 years (6/12-6 9/12) since the last nodule-free US thyroid scan. Conclusions Sonographic follow-up assessments warrant further exploration as a strategy to determine PTC susceptibility in the paediatric population.

Background The phenotypic heterogeneity of circulating tumor cells (CTC) in peripheral blood and disseminated tumor cells (DTC) in bone marrow is an important constraint for clinical decision making. Here, we investigated the implications of two different subpopulations of these cells in gastric cancer (GC). Methods GC patients (n = 228) who underwent elective gastric resections were prospectively examined for CTC/DTC. The cells obtained from peripheral blood and bone marrow aspirates were sorted by flow cytometry and CD45 − cells expressing cytokeratins (8, 18, and 19) Conclusion CD44+ phenotype of cytokeratin-positive cells in blood and bone marrow is an independent prognostic factor in patients with gastric cancer.

BackgroundTumour cells release membrane micro(nano)fragments called tumour-derived microvesicles (TMV) that are believed to play an important role in cancer progression. TMV suppress/modify antitumour response of the host, but there is also some evidence for their direct interaction with cancer cells. In cancer patients TMV are present in body fluid and tumour microenvironment. The present study aimed at characterization of whole types/subpopulations, but not only exosomes, of TMV from newly established gastric cancer cell line (called GC1415) and to define their interactions with autologous cells.MethodsTMV were isolated from cell cultures supernatants by centrifugation at 50,000×g and their phenotype was determined by flow cytometry. The size of TMV was analysed by dynamic light scattering and nanoparticle tracking analysis, while morphology by transmission electron microscopy and atomic force microscopy. Interactions of TMV with cancer cells were visualized using fluorescence-activated cell sorter, confocal and atomic force microscopy, biological effects by xenografts in NOD SCID mice.ResultsIsolated TMV showed expression of CD44H, CD44v6 (hyaluronian receptors), CCR6 (chemokine receptor) and HER-2/neu molecules, exhibited different shapes and sizes (range 60–900 nm, highest frequency of particles with size range of 80–120 nm). TMV attached to autologous cancer cells within 2 h and then were internalized by them at 24 h. CD44H, CD44v6 and CCR6 molecules may play a role in attachment of TMV to cancer cells, while HER-2 associated with CD24 be involved in promoting cancer cells growth. Pre-exposure of cancer cells to TMV resulted in enhancement of tumour growth and cancer cell-induced angiogenesis in NOD SCID mice model.ConclusionsTMV interact directly with cancer cells serving as macro-messengers and molecular cargo transfer between gastric cancer cells resulting in enhancement of tumour growth. TMV should be considered in future as target of anticancer therapy.