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Nerve growth factor effects on human and mouse melanoma cell invasion and heparanase production
1Department of Tumor Biology, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Abstract:
The role of growth factor networks in regulating the progression of human melanocytes towards tumorigenicity and ultimately the malignant phenotype is poorly understood. In particular, the autocrine and paracrine influences that modulate cellular invasion and extracellular matrix degradative enzymes of melanoma cells remain undefined at the molecular level. We report here that nerve growth factor (NGF) can modify some metastasis-associated cellular properties of human and mouse melanoma cells. Treatment of early-passage human metastatic melanoma cells (MeWo) or their variants (3S5, 70W) with biologically active 2.5S NGF resulted in (a) delayed density-dependent inhibition of melanoma cell growth; (b) increased in vitro invasion through a reconstituted basement membrane; and (c) time- and dose-dependent induction of heparanase, a heparan-sulfate-specific endo-beta-D-glucuronidase associated with human melanoma metastasis. These effects of NGF were most marked in the 70W brain-colonizing cells (70W > MeWo > 3S5). The NGF enhancement of heparanase secretion was not species-specific, since it was also observed in murine B16 melanoma cells; the highest NGF stimulation of heparanase was found in brain-colonizing murine B16-B15b variant (B16-B15b > B16-BL6, B16-F10, B16-F1). NGF also increased the invasive capacity of the human 70W and murine B16-B15b sublines in a chemoinvasion assay performed with filters coated with purified heparan sulfate proteoglycan (HSPG). The enhancement of chemotactic response and heparanase production was detected at NGF concentrations sufficient to fully saturate both low- and high-affinity NGF receptors (NGFR), the neurotrophin receptor (p75) and the trkA gene product, respectively. The results suggest that, in addition to the effects of NGF on cellular development and differentiation within the peripheral and central nervous systems, NGF can exert changes in the invasive properties of neuroectoderm-derived melanoma cells.
Insights
Nerve growth factor (NGF) promotes melanoma cell invasion and metastasis by increasing heparanase, an enzyme linked to tumor spread. This study reveals NGF
Area of Science:
- Oncology
- Molecular Biology
- Cell Biology
Background:
- The role of growth factors in melanoma progression is not fully understood.
- Melanoma cell invasion and metastasis are complex processes involving extracellular matrix degradation.
- The specific molecular mechanisms by which autocrine and paracrine factors influence melanoma metastasis are largely undefined.
Purpose of the Study:
- To investigate the effect of nerve growth factor (NGF) on the metastatic properties of human and mouse melanoma cells.
- To determine if NGF influences cellular invasion and the production of extracellular matrix-degrading enzymes in melanoma.
- To elucidate the molecular pathways through which NGF may modulate melanoma tumorigenicity.
Main Methods:
- Treatment of human (MeWo, 3S5, 70W) and murine (B16 variants) melanoma cells with biologically active 2.5S NGF.
- Assays for density-dependent growth inhibition, in vitro invasion through a reconstituted basement membrane, and heparanase induction.
- Chemoinvasion assays using filters coated with heparan sulfate proteoglycan (HSPG).
- Analysis of NGF receptor (NGFR) saturation to correlate effects with receptor binding.
Main Results:
- NGF treatment delayed density-dependent growth inhibition and increased in vitro invasion of melanoma cells.
- NGF induced time- and dose-dependent secretion of heparanase, an enzyme associated with melanoma metastasis.
- These effects were more pronounced in brain-colonizing melanoma sublines (70W, B16-B15b).
- NGF enhanced the invasive capacity of human and murine melanoma cells in chemoinvasion assays.
- NGF-induced effects on invasion and heparanase production occurred at concentrations saturating both low- and high-affinity NGF receptors.
Conclusions:
- NGF can modify metastasis-associated cellular properties of melanoma cells, including invasion and heparanase production.
- NGF's influence on heparanase secretion is not species-specific and is particularly potent in brain-colonizing variants.
- NGF may play a significant role in the invasive behavior of neuroectoderm-derived melanoma cells, beyond its known functions in the nervous system.