Search

Hyaluronectin (HN) is a glycoprotein with a high affinity to hyaluronic acid (HA) and known to be a component of the extracellular matrix of tumours. Clinical studies have shown that a low level of HN correlates to tumours with poor prognosis, whereas a high level of HN correlates to tumours with good prognosis. We previously demonstrated in vitro that hyaluronidase activity, which promotes tumour progression and metastatic spread by degradation of HA into angiogenic oligosaccharides, was inhibited or promoted by HN, according to the level of HN-expression. This raises the question of the role played by HN in cancer, and particularly if high and low levels of HN-expression could trigger opposite effects on tumour growth and/or metastatic spread. To address this issue, we used a model of spontaneous lung fluorescent metastases that we characterised previously. We stably transfected the human HN cDNA into fluorescent H460MGFP cells and selected two clones characterised by different levels of HN-expression: HN110 and HN704, with a high and a low level of HN-expression, respectively. In vitro, we demonstrated that HN704 cell migration was significantly increased. Inoculation of clones to nude mice had no significant effect on tumour growth, but clearly revealed opposite effects on metastatic spread: HN110 significantly decreased the number of fluorescent metastases whereas HN704 significantly increased it. We also analysed HN, HA and hyaluronidase contents in sera and tumours. These results demonstrate that HN can play a role as either a suppressor or promoter of metastatic spread.

The inter-alpha trypsin inhibitor (ITI) family is a group of proteins built up from different combinations of I light chain (ITI-L) and 3 highly homologous heavy chains (ITI-HI, -H2 and -H3). To investigate a potential role of the ITI family chains in cancer and metastasis spreading, we engineered human H460M cell lines expressing both the green fluorescent protein (GFP) and one of these chains. These clones were subcutaneously injected in athymic nude mice, and lung metastasis number and primary tumor weight were determined after 28 days. Expression of the ITI-L chain considerably decreased tumor weight and fluorescent lung metastasis number. ITI-HI and ITI-H3 chain expression induced a significant decrease of metastasis number, whereas no decrease of tumor weight could be detected. In vitro, ITI-L expression significantly decreased chemotaxis and ITI-HI and ITI-H3 expression increased cell attachment. These results argue for the antitumoral or antimetastatic properties of ITI-L, -HI and -H3 chains., (Copyright 2001 Wiley-Liss, Inc.)

The authors describe a model of spontaneous lung metastases in nude mice using green fluorescent protein (GFP) expression as a marker. The human lung cell line H460M was transfected with the humanised GFP-S65T cDNA and a stable fluorescent cell line termed H460M(GFP) was obtained. The latter kept in vitro biological features when compared to the parental H460M cell line, which suggests that GFP-expression does not influence H460M(GFP) cell line behaviour. In order to evaluate their metastatic potential and to determine the number of spontaneous metastases, H460M(GFP) cells were subcutaneously inoculated into nude mice. Animals were sacrificed at time intervals and tissues (lung, liver, spleen, node, and kidney) were analysed under fluorescence microscopy. These experiments demonstrated that 2 weeks after subcutaneous inoculation, 75% of animals exhibited fluorescent spontaneous lung micrometastases. From the third week, 100% of animals exhibited an increasing number of metastases (10-16) which were only localised in the lungs. At the end of the study, the number of lung metastases had dramatically increased (42-400 at 7 weeks). Although these metastases were mainly localised in lung, a few mice had an invasion of neighbouring lymph nodes. The H460M(GFP) cell line allowed to follow the seeding and development of spontaneous lung metastases and may be considered a simple and powerful tool to study each step of the metastasis to screen new anticancer drugs.