Identification of a new seven-span transmembrane protein: NGX6a is downregulated in nasopharyngeal carcinoma and is associated with tumor metastasis.
Nasopharyngeal carcinoma (NPC)-associated gene 6 (NGX6) is a novel candidate metastasis suppressor gene that can significantly decrease the growth, motility, and invasion of NPC cells. In this study, we generated a highly specific NGX6 polyclonal antibody and analyzed its distribution in the human fetus by Western blot and immunohistochemistry. The result of the Western blot showed the protein of NGX6 had two types of isoforms, isoform a (NGX6a) and isoform b (NGX6b). Isoform a is composed of 472 amino acids with a calculated molecular mass of 52 kDa, whereas isoform b is composed of 338 amino acids with a calculated molecular mass of 37 kDa. It is predicated that there is an epidermal growth factor domain in the N terminal of both a and b isoforms, and seven transmembrane domains in NGX6a, but only two transmembrane domains in NGX6b. The expression level of NGX6a was higher than that of NGX6b in human fetal tissue. Obvious high expression of NGX6a protein presents in the nervous system and epithelial tissues of the human fetus, but the NGX6b protein (37 kDa) is mainly expressed in the nervous system. We further analyzed the tissue microarray, which contained 154 NPC biopsies and 70 non-NPC biopsies, and found that NGX6a was significantly downregulated in NPC and associated with tumor metastasis.
Wang
Li
L
Cancer Research Institute, Xiangya Hospital, Central South University, Changsha, Hunan 410078, China.
Xiang
Bo
B
Yi
Mei
M
Zhang
Wen-Ling
WL
Yang
Jian-Bo
JB
Peng
Shu-Ping
SP
Li
Xiao-Ling
XL
Li
Gui-Yuan
GY
D000906:Antibodies; D000918:Antibody Specificity; D001921:Brain / Q000201:enzymology; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology*; D017931:DNA Primers; D015536:Down-Regulation; D005333:Fetus; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics* / Q000276:immunology; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000473:pathology*; D009362:Neoplasm Metastasis / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000276:immunology; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000276:immunology
D000906:Antibodies; D017931:DNA Primers; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C477325:TMEM8B protein, human; D025521:Tumor Suppressor Proteins