Genomics and proteomics approaches to the study of cancer-stroma interactions.

BACKGROUND: The development and progression of cancer depend on its genetic characteristics as well as on the interactions with its microenvironment. Understanding these interactions may contribute to diagnostic and prognostic evaluations and to the development of new cancer therapies. Aiming to investigate potential mechanisms by which the tumor microenvironment might contribute to a cancer phenotype, we evaluated soluble paracrine factors produced by stromal and neoplastic cells which may influence proliferation and gene and protein expression. METHODS: The study was carried out on the epithelial cancer cell line (Hep-2) and fibroblasts isolated from a primary oral cancer. We combined a conditioned-medium technique with subtraction hybridization approach, quantitative PCR and proteomics, in order to evaluate gene and protein expression influenced by soluble paracrine factors produced by stromal and neoplastic cells. RESULTS: We observed that conditioned medium from fibroblast cultures (FCM) inhibited proliferation and induced apoptosis in Hep-2 cells. In neoplastic cells, 41 genes and 5 proteins exhibited changes in expression levels in response to FCM and, in fibroblasts, 17 genes and 2 proteins showed down-regulation in response to conditioned medium from Hep-2 cells (HCM). Nine genes were selected and the expression results of 6 down-regulated genes (ARID4A, CALR, GNB2L1, RNF10, SQSTM1, USP9X) were validated by real time PCR. CONCLUSIONS: A significant and common denominator in the results was the potential induction of signaling changes associated with immune or inflammatory response in the absence of a specific protein.

Human chronic Mansonian schistosomiasis-cell proliferation and fibre formation in the hepatic sinusoidal wall: a morphometric, light and electron-microscopy study.

A morphometric, light and electron-microscopy study of the sinusoids in human Mansonian schistosomiasis with and without portal hypertension showed a sequence of events beginning with an increased number of cell nuclei, particularly evident at the centrolobular region. This is followed by deposition of reticulin fibres along the perisinusoidal space. Later, increased numbers of cells and reticulin fibres are seen throughout the lobule. Other findings, such as reduplication of the sinusoidal lining and the focal appearance beneath the cell layer of the thin discontinuous membrane, were also reported. This perisinusoidal fibrosis probably adds an element of heightened intrasinusoidal pressure to the perisinusoidal hypertension already described in this disease. Its pathogenic mechanism is obscure. The hepatic sinusoids in Mansonian schistosomiasis receive mainly arterial blood. High intraluminal pressure could be one explanation of the perisinusoidal fibrosis in these cases. However, as possibly occurs in primary sinusoidal portal hypertension, chronic immunological stimulation leading to proliferation of Küpffer cells and lipocytes could be an alternative mechanism.

Human schistosomiasis: Schistosoma mansoni antigen detection in renal glomeruli.

Twelve kidney, five biopsy and seven necropsy specimens, all from schistosomiasis mansoni patients were studied by light and immunoflurescent microscopy in an attempt to detect antigen in the glomerular walls. Deposits of IgM, IgG,I gA, IgE, complement C3 and fibrinogen were observered in most cases. Antigen was successfully detected in two cases(one biopsy and one necropsy specimen), both exhibiting proliferative glomerulonephritis. The only clinical manifestation was a slight proteinuria. IgG antibodies eluted from the sutopsy kidney homogenates showed specific binding mostly to Schistosoma mansoni gut, thus spggesting that the fixed antibodies (eluates) are, at least partially, consituted by antibodies similar to the anti-circulating antigen. These data reinfroce the hypothesis that renal injury in schistosomiasis is mediated through an immune complex disease.