title: Selected GRIN2A mutations in melanoma cause oncogenic effects that can be modulated by extracellular glutamate.
abstract: GRIN2A mutations are frequent in melanoma tumours but their role in disease is not well understood. GRIN2A encodes a modulatory subunit of the N-methyl-d-aspartate receptor (NMDAR). We hypothesized that certain GRIN2A mutations increase NMDAR function and support melanoma growth through oncogenic effects. This hypothesis was tested using 19 low-passage melanoma cell lines, four of which carried novel missense mutations in GRIN2A that we previously reported. We examined NMDAR expression, function of a calcium ion (Ca2+) channel and its contribution to cell growth using pharmacological modulators; findings were correlated with the presence or absence of GRIN2A mutations. We found that NMDAR expression was low in all melanoma cell lines, independent of GRIN2A mutations. In keeping with this, NMDAR-mediated Ca2+influx and its contribution to cell proliferation were weak in most cell lines. However, certain GRIN2A mutations and culture media with lower glutamate levels enhanced NMDAR effects on cell growth and invasion. The main finding was that G762E was associated with higher glutamate-mediated Ca2+influx and stronger NMDAR contribution to cell proliferation, compared with wild-type GRIN2A and other GRIN2A mutations. The pro-invasive phenotype of mutated cell lines was increased in culture medium containing less glutamate, implying environmental modulation of mutation effects. In conclusion, NMDAR ion channel function is low in cultured melanoma cells but supports cell proliferation and invasion. Selected GRIN2A mutations, such as G762E, are associated with oncogenic consequences that can be modulated by extracellular glutamate. Primary cultures may be better suited to determine the role of the NMDAR in melanoma in vivo.
authors.affiliation: Department of Molecular Medicine and Pathology, University of Auckland, Private Bag 92019, Auckland, New Zealand; Auckland Cancer Society Research Centre, University of Auckland, Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Stacey Ann N
authors.initials: SA
authors.lastname: D'mello
authors.affiliation: Auckland Cancer Society Research Centre, University of Auckland, Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Wayne R
authors.initials: WR
authors.lastname: Joseph
authors.affiliation: Department of Molecular Medicine and Pathology, University of Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Taryn N
authors.initials: TN
authors.lastname: Green
authors.affiliation: Auckland Cancer Society Research Centre, University of Auckland, Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Euphemia Y
authors.initials: EY
authors.lastname: Leung
authors.affiliation: Cancer Genetics and Neuroscience Program, Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, OH 43210, United States.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: During
authors.affiliation: Department of Molecular Medicine and Pathology, University of Auckland, Private Bag 92019, Auckland, New Zealand; Auckland Cancer Society Research Centre, University of Auckland, Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Graeme J
authors.initials: GJ
authors.lastname: Finlay
authors.affiliation: Auckland Cancer Society Research Centre, University of Auckland, Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Bruce C
authors.initials: BC
authors.lastname: Baguley
authors.affiliation: Department of Molecular Medicine and Pathology, University of Auckland, Private Bag 92019, Auckland, New Zealand; LabPlus Haematology, Auckland City Hospital, Private Bag 92024, Auckland, New Zealand. Electronic address: m.kalev@auckland.ac.nz.
authors.forename: Maggie L
authors.initials: ML
authors.lastname: Kalev-Zylinska
mesh_terms: D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D018698:Glutamic Acid / Q000494:pharmacology*; D006801:Humans; D008545:Melanoma / Q000235:genetics* / Q000473:pathology; D009154:Mutation; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D002118:Calcium; D018698:Glutamic Acid; D016194:Receptors, N-Methyl-D-Aspartate
keywords: Calcium; Cancer; Ion channel; Melanoma; NMDA receptor; Oncogene; Tumor suppressor