Neogenin defined as a GD3-associated molecule by enzyme-mediated activation of radical sources confers malignant properties via intra-cytoplasmic domain in melanoma cells.

Neogenin defined as a GD3-associated molecule by enzyme-mediated activation of radical sources confers malignant properties via intra-cytoplasmic domain in melanoma cells.

J Biol Chem. 2016 Jun 10;

Authors: Kaneko K, Ohkawa Y, Hashimoto N, Ohmi Y, Kotani N, Honke K, Ogawa M, Okajima T, Furukawa K, Furukawa K

Abstract
To investigate mechanisms for increased malignant properties in malignant melanomas by gangliosdide GD3, enzyme-mediated activation of radical sources and subsequent mass spectrometry were performed using an anti-GD3 antibody, and GD3-positive (GD3+) and GD3-negative (GD3-) melanoma cell lines. Neogenin defined as a GD3-neighbored molecule was largely localized in lipid/rafts in GD3+ cells. Silencing of neogenin resulted in the reduction of cell growth and invasion activity. Physical association between GD3 and neogenin was demonstrated by immunostaining of the immunoprecipitates with anti- neogenin antibody from GD3+ cell lysates. Intra-cytoplasmic domain of neogenin (Ne-ICD) was detected in GD3+ cells at higher levels than in GD3- cells when cells were treated by a proteasome inhibitor, but not when simultaneously treated with a γ-secretase inhibitor. Over-expression of Ne-ICD in GD3- cells resulted in the increased cell growth and invasion activity, suggesting that Ne-ICD plays a role as a transcriptional factor to drive malignant properties of melanomas after cleavage with γsecretase. γ-secretase was found in lipid/rafts in GD3+ cells. Accordingly, immunocytostaining revealed that GD3, neogenin and γ-secretase were co-localized at the leading edge of GD3+ cells. All these results suggested that GD3 recruits γ-secretase to lipid/rafts, allowing efficient cleavage of neogenin. ChIP-sequensing was performed to identify candidates of target genes of Ne-ICD. Some of them actually showed increased expression after expression of Ne-ICD, probably exerting malignant phenotypes of melanomas under GD3 expression.

PMID: 27288875 [PubMed - as supplied by publisher]

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via IFTTT