Model systems of carcinoma cell dispersion

Metastasis tumour suppressor-1 and the aggressiveness of prostate cancer cells

Previous studies have suggested that metastasis tumour suppressor-1 (MTSS1) plays a key role in cancer metastasis. Firstly, in this study we assessed MTSS1 expression levels in prostate cancer cell lines to reveal any changes in cell properties. Secondly, we aimed to clarify the cellular function of MTSS1 in prostate cancer cells. MTSS1 expression levels were assessed in different types of cancer cell lines through the RT-PCR analysis technique. The influence of MTSS1 was further examined via biological overexpression and knockdown in the prostate cancer cell lines. Two prostate cell lines were chosen for either knockdown or overexpression of the MTSS1 gene. The overexpression of MTSS1 in PC-3 human prostate cancer cells significantly suppressed the migratory, growth and adherence properties of the cells (p<0.01). By contrast, the knockdown of MTSS1 in DU-145 human prostate cancer cells dramatically enhanced these properties (p<0.001). We concluded that MTSS1 demonstrates the ability to play a role in controlling the metastatic nature of prostate cancer cells.

Pathogenesis of bone metastasis: a review

BACKGROUND

Metastasic deposits from malignancies frequently lodge in the skeleton, including the jaw bones.

METHOD

A review of the literature was performed in order to provide a coherent overview on the pathogenesis of bone metastasis.

RESULTS

Bone metastasis follows complex molecular interactions that enable tumor cells to detach from the primary site, invade the extracellular matrix, intra-vasate, extra-vasate, and proliferate within bone. They induce local bone changes that could manifest radiologically as either osteolytic or radiodense. In addition to the direct bone changes, malignancies can elaborate mediators that are released in circulation, leading to generalized osteopenia.

CONCLUSIONS

The spread of malignant neoplasms to bone is not a random process but rather a cascade of specific molecular events orchestrated through complex interactions between neoplastic cells and their environment.

A comparative evaluation of various invasion assays testing colon carcinoma cell lines

Various colon carcinoma cell lines were tested in different invasion assays, i.e. invasion into Matrigel, into confluent fibroblast layers and into chicken heart tissue. Furthermore, invasive capacity and metastatic potential were determined in nude mice. The colon carcinoma cells used were the human cell lines Caco-2, SW-480, SW-620 and HT-29, and the murine lines Colon-26 and -38. None of the human colon carcinoma cells migrated through porous membranes coated with Matrigel; of the murine lines, only Colon-26 did. When incubated in a mixture of Matrigel and culture medium non-invading cells formed spheroid cultures, whereas invading cells showed a stellate outgrowth. Only the heterogeneously shaped (epithelioid and stellate) cells of SW-480 and SW-620 and the spindle-shaped cells of Colon-26 invaded clearly confluent skin and colon fibroblasts as well as chicken heart tissue. However, when transplanted into the caecum of nude and syngeneic mice, all the lines tested were invasive with the exception of Caco-2 cells. We conclude that the outcome of in vitro tests measuring the invasive capacity of neoplastic cells is largely dependent on the test system used. Invasive capacity in vitro is strongly correlated with cells having a spindle cell shape, vimentin expression and E-cadherin down regulation. In contrast, HT-29 and Colon-38 cells having an epithelioid phenotype were clearly invasive and metastatic in vivo, but not in vitro.

Epidermal growth factor (EGF)- and scatter factor/hepatocyte growth factor (SF/HGF)- mediated keratinocyte migration is coincident with induction of matrix metalloproteinase (MMP)-9

Receptor tyrosine kinases are key regulators of cellular function including cell growth, differentiation, migration, and morphogenesis. Disruptions of receptor tyrosine kinase signaling pathways are often associated with changes in cellular proliferative capacity and tumorigenesis. Both receptor-specific and cell type-specific factors may contribute to the ultimate cellular responses observed after receptor activation. In this regard, we find that both normal keratinocytes and their tumorigenic counterparts display differential responses to activation of receptor tyrosine kinases. Multiple ligands were mitogenic for keratinocytes, but only epidermal growth factor (EGF), transforming growth factor alpha (TGFalpha), and scatter factor/hepatocyte growth factor (SF/HGF) promoted cell motility as assessed by colony dispersion (scattering) and in vitro reepithelialization. Interestingly, growth factor specificity for motility coincided with ligand-mediated cell invasion through a reconstituted basement membrane and induction of the 92-kDa metalloproteinase (MMP-9) activity as determined by gelatin zymogram analysis. Inhibitors of MMP activity or addition of an MMP-9 neutralizing antibody resulted in the loss of growth factor-induced colony dispersion, suggesting a functional role for MMP-9 induction during this response. Coordinate regulation of MMP-9 induction and the migratory response are likely to contribute to the enhanced invasive potential observed in response to EGF and SF/HGF. Our findings suggest that alternate receptor-mediated signaling pathways leading to differences in gene expression may be involved in complex cellular responses such as colony dispersion or invasion.