
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 
Kato
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
E-mail: katomasa@isc.chubu.ac.jp
        
        
          
            
              | AJCR Copyright © 2010-present, All rights reserved. Published by e-Century Publishing Corporation, Madison, WI 53711, USA 
 | 
          
         
                
        American Journal of Cancer Research