Suppression of activin A signals inhibits growth of malignant pleural mesothelioma cells.

BACKGROUND: Activins control the growth of several tumour types including thoracic malignancies. In the present study, we investigated their expression and function in malignant pleural mesothelioma (MPM). METHODS: The expression of activins and activin receptors was analysed by quantitative PCR in a panel of MPM cell lines. Activin A expression was further analysed by immunohistochemistry in MPM tissue specimens (N=53). Subsequently, MPM cells were treated with activin A, activin receptor inhibitors or activin-targeting siRNA and the impact on cell viability, proliferation, migration and signalling was assessed. RESULTS: Concomitant expression of activin subunits and receptors was found in all cell lines, and activin A was overexpressed in most cell lines compared with non-malignant mesothelial cells. Similarly, immunohistochemistry demonstrated intense staining of tumour cells for activin A in a subset of patients. Treatment with activin A induced SMAD2 phosphorylation and stimulated clonogenic growth of mesothelioma cells. In contrast, treatment with kinase inhibitors of activin receptors (SB-431542, A-8301) inhibited MPM cell viability, clonogenicity and migration. Silencing of activin A expression by siRNA oligonucleotides further confirmed these results and led to reduced cyclin D1/3 expression. CONCLUSION: Our study suggests that activin A contributes to the malignant phenotype of MPM cells via regulation of cyclin D and may represent a valuable candidate for therapeutic interference.

Invasion from a cell aggregate--the roles of active cell motion and mechanical equilibrium.

Cell invasion from an aggregate into a surrounding extracellular matrix (ECM) is an important process during development disease, e.g., vascular network assembly or tumor progression. To describe the behavior emerging from autonomous cell motility, cell-cell adhesion and contact guidance by ECM filaments, we propose a suitably modified cellular Potts model. We consider an active cell motility process in which internal polarity is governed by a positive feedback from cell displacements, a mechanism that can result in highly persistent motion when constrained by an oriented ECM structure. The model allows us to explore the interplay between haptotaxis, matrix degradation and active cell movement. We show that for certain conditions the cells are able to both invade the ECM and follow the ECM tracks. Furthermore, we argue that enforcing mechanical equilibrium within a bulk cell mass is of key importance in multicellular simulations.

A new multiplex PCR for differential identification of Shigella flexneri and Shigella sonnei and detection of Shigella virulence determinants.

Most of the multiplex PCR (mPCR) used to identify Shigella do not discriminate between Shigella species or serotypes. We designed a mPCR to differentiate between S. flexneri and S. sonnei strains based on the detection of markers associated with the she pathogenicity island described in Shigella. In addition, specific primers were included to detect the Shigella virulence determinants ShET-1 and ShET-2 enterotoxin genes. The analysis of 304 Shigella strains from Chile and 79 Shigella strains from other geographic locations indicated that the mPCR described here detected all Shigella species and specifically differentiated S. flexneri and S. sonnei. The technique was sensitive, reproducible, specific and simple to perform, providing a new tool with the potential to be employed for epidemiological and diagnostic purposes.

Selective Inhibition of HIF1α Expression by ZnSO4 Has Antitumoral Effects in Human Melanoma.

Zinc as an essential trace metal is a ubiquitous component of various molecules of the cell. Studies indicated that it may modulate functions of various cancer cell types, and can even inhibit metastasis formation in experimental models. In melanoma, zinc was shown to affect melanin production and to induce apoptosis. Using human melanoma cell lines, we have tested the effects of ZnSO4 on cell proliferation, survival, migration as well as in vivo on experimental liver colony formation. We have found that ZnSO4 has antiproliferative and proapoptotic effects in vitro. In SCID mice intraperitoneal administration of ZnSO4 specifically inhibited liver colony formation without affecting primary tumor growth. To reveal the molecular mechanisms of action of zinc in human melanoma, we have tested mRNA expression of zinc finger transcription factors and found a strong inhibitory effect on HIF1α, as compared to WT1 whereas HIF2α and MTF1 expression was unaffected. Immunohistochemical detection of HIF1α protein in liver metastases confirmed its decreased nuclear expression after in vivo ZnSO4 treatment. These data indicate that in human melanoma zinc administration may have an antimetastatic effect due to a selective downregulation of HIF1α.

Mid-Infrared Imaging Is Able to Characterize and Separate Cancer Cell Lines.

Malignancies are still responsible for a large share of lethalities. Macroscopical evaluation of the surgical resection margins is uncertain. Big data based imaging approaches have emerged in the recent decade (mass spectrometry, two-photon microscopy, infrared and Raman spectroscopy). Indocianine green labelled MS is the most common approach, however, label free mid-infrared imaging is more promising for future practical application. We aimed to identify and separate different transformed (A-375, HT-29) and non-transformed (CCD986SK) cell lines by a label-free infrared spectroscopy method. Our approach applied a novel set-up for label-free mid-infrared range classification method. Transflection spectroscopy was used on aluminium coated glass slides. Both whole range spectra (4000-648 cm-1) and hypersensitive fingerprint regions (1800-648 cm-1) were tested on the imaged areas of cell lines fixed in ethanol. Non-cell spectra were possible to be excluded based on mean transmission values being above 90%. Feasibility of a mean transmission based spectra filtering method with principal component analysis and linear discriminant analysis was shown to separate cell lines representing different tissue types. Fingerprint region resulted the best separation of cell lines spectra with accuracy of 99.84% at 70-75 mean transmittance range. Our approach in vitro was able to separate unique cell lines representing different tissues of origin. Proper data handling and spectra processing are key steps to achieve the adaptation of this dye-free technique for intraoperative surgery. Further studies are urgently needed to test this novel, marker-free approach.