Invasive Potential Of Melanoma Cells Research Articles

Migration and metalloproteinases determine the invasive potential of mouse melanoma cells, but not melanin and telomerase

The biological characteristic cell locomotion and invasion, melanin content, metalloproteinases and telomerase activity were studied in a parental mouse melanoma cell line B16 and two descendents B16BL6 and B16F10. The invasive potential of melanoma cells was assayed in a transwell cell culture chamber. Melanin content was determined by the absorbance value at 470 nm per 10 6 cells. Tumor cells migration within the 3-D collagen matrix was microscopically recorded with a time-lapse video recorder and analyzed by computer-assisted cell tracking. Gelatin zymography was adopted to assay the metalloproteinases secretion. A polymerase chain reaction-based telomeric repeat amplification protocol (TRAP) was used for measuring telomerase activity. The results demonstrated that B16BL6 and B16F10 cells were highly invasive compared to B16 cells, but the melanin content of B16F10 was very low. B16F10 and B16BL6 were hypermotile and secreted much more metalloproteinases than B16. No differences were observed in telomerase activity among the three melanoma cell lines. Invasion of mouse melanoma was closely correlated to tumor cell migration and secretion of metalloproteinases. Melanin content and telomerase activity were phenotypically not related to invasiveness in these three mouse melanoma cell lines.

Mutation and expression of the low affinity neurotrophin receptor in human malignant melanoma.

The low affinity p75 neurotrophin receptor (p75NTR) is a cysteine-rich transmembrane glycoprotein which is frequently overexpressed in advanced stages of human melanoma. The biological consequences of this overexpression are unknown; however, it has recently been shown that p75NTR can enhance the invasive potential of melanoma cells in vitro. In the present study we examined cell lines established from normal human melanocytes and metastatic melanomas for expression of p75NTR mRNA and protein. The results showed that, compared with normal melanocytes, levels of p75NTR-specific protein were high in seven melanoma lines, markedly decreased in two melanoma lines and comparable in two melanoma lines. The conserved transmembrane domain of p75NTR was analysed for point mutations by single strand conformation polymorphism analysis and direct DNA sequencing. Identical point mutations were detected in the transmembrane domain of p75NTR in the two melanoma lines with reduced p75NTR protein expression, which resulted in the substitution of the uncharged amino acid Gly for the negatively-charged Asp.

Inhibitory effect of human fibroblast interferon (HuIFN-beta) on the growth and invasive potential of cultured human melanoma cells in vitro.

The effect of HuIFN-beta on the invasive potential of melanoma cells was studied using an in-vitro model system with Transwell chambers equipped with matrigel-coated polycarbonate filters. When (10(2), 10(3) and 10(4) IU/ml) for 3 days and then grown in medium without HuIFN-beta for another 7 days. On day 7, the proliferation of melanoma cells was inhibited by 77 and 87%, respectively, when cells were treated with 10(2) and 10(4) IU/ml of HuIFN-beta. This antiproliferative effect was dose-dependent and more pronounced on day 11. The effect of HuIFN-beta on the invasive potential of melanoma cells was studied using an in-vitro model system with Transwell chambers equipped with Matrigel-coated polycarbonate filters. When cells were treated with HuIFN-beta (10(2), 10(3) and 10(4) IU/ml) for 24 h, the amount of tritiated thymidine incorporated into cells was increased, indicating that cell growth was not inhibited. However, the number of cells that invaded to the filter decreased significantly by 15-40%. HuIFN-beta did not have an inhibitory effect on the haptotactic migration of melanoma cells. These data indicate that the antiproliferative effect of HuIFN-beta occurs after 24 h and that the direct anti-invasive effect is independent of any effect on proliferation.