Am J Cancer Res 2012;2(3):322-329

Original Article
Reduced GNG2 expression levels in mouse and human malignant melanomas

Ichiro Yajima, Mayuko Y Kumasaka, Yuji Naito, Toshikazu Yoshikawa, Hiro Takahashi, Yoko Funasaka, Tamio Suzuki, Masashi

Unit of the Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu
University, Japan; Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
College of Bioscience and Biotechnology, Chubu University, Matsumoto-cho 1200, Kasugai, Aichi 487-8501, Japan; Department
of Dermatology, Nippon Medical School, Tokyo 113-8602, Japan; Department of Dermatology, Yamagata University School of
Medicine, Yamagata 990-9585, Japan.

Received January 23, 2012; accepted February , 2012; Epub February , 2012; Published February, 2012

Abstract: Heterotrimeric G protein is composed of a Gα-subunit and a Gβγ-dimer. Previous studies have revealed that Gβγ-
dimers including the Gγ2 subunit (Gng2/GNG2) were associated with cell proliferation, differentiation, invasion and
angiogenesis. At present, however, there is no information on the expression level of Gng2/GNG2 alone in any kinds of tumor. In
this study, we performed DNA microarray analysis in benign melanocytic tumors and malignant melanomas from RET-
transgenic mice (RET-mice). Gng2 transcript expression levels in malignant melanomas were less than 1/10 of that in a benign
tumor. The difference in Gng2 transcript expression levels between benign tumors and malignant melanomas was greatest
among all of the G protein γ subunits examined in this study. Moreover, protein expression levels of Gng2 were decreased in
malignant melanomas compared with those in benign melanocytic tumors in RET-mice. Analysis of human malignant
melanomas also showed reduced GNG2 transcription and protein expression levels in five human malignant melanoma cell
lines compared with the expression level in normal human epithelial melanocytes (NHEM). Thus, we demonstrated for the first
time that Gng2/GNG2 expression levels are reduced in malignant melanoma, suggesting that GNG2 could be a novel biomarker
for malignant melanoma. (AJCR00000105).

Keywords: G-protein, gamma subunit, malignant melanoma

Address all correspondence to:
Dr. Masashi Kato
Unit of Environmental Health Sciences
Department of Biomedical Sciences
College of Life and Health Sciences (Building no. 50, 11F)
Chubu University, 1200 Matsumoto-cho, Kasugai-shi, Aichi 487-8501, Japan.
Phone: +81-568-51-7364, FAX: +81-568-51-9635
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American Journal of Cancer Research
ISSN: 2156-6976