Overexpression of betaPix-a in human breast cancer tissues.
Pak interacting exchange factor (betaPix) is a recently cloned protein that contains a multidomain with many potential binding sites and is known to be involved in the regulation of Cdc42/Rac GTPases and Pak kinase activity. These domains of betaPix appear to play a critical role in the regulation of the cytoskeletal organization. The overexpression of betaPix enhances the activation of p38, which is thought to be an important downstream effector of the Rho GTPase family (Rac, Cdc42), which are involved in increased membrane ruffling and cell motility. This increase of cell mobility is an important feature of cancer invasion. We examined the expression of betaPix-a in human breast cancer tissues and adjacent normal tissues obtained from 39 breast cancer patients. Immunoblot analysis and RT-PCR revealed that betaPix-a expression was significantly increased in 37 of the 39 breast cancer tissues (94.9%) versus normal breast tissues. Immunohistochemical analysis showed that breast cancer tissues have consistently stronger immunoreactivity to betaPix-a antibodies than normal tissues. betaPix-a overexpression was inversely associated with extensive intraductal component (P<0.001). In conclusion, betaPix-a expression was found to be higher in human breast cancer tissues than in normal breast tissues, which implies a role for betaPix-a in human breast tumorigenesis. We suggest that betaPix-a may be a useful marker of malignant disease in the breast.
Ahn
Soo-Jung
SJ
Cancer Research Institute, Seoul National University, 28 Yongon-Dong, Jongno-Gu, Seoul 110-744, South Korea.
Chung
Ki-Wook
KW
Lee
Ryung-Ah
RA
Park
In-Ae
IA
Lee
Seung-Hye
SH
Park
Dong-Eun
DE
Noh
Dong-Young
DY
D000328:Adult; D000368:Aged; D001665:Binding Sites; D001943:Breast Neoplasms / Q000201:enzymology*; D018797:Cell Cycle Proteins / Q000096:biosynthesis*; D002465:Cell Movement; D003599:Cytoskeleton / Q000378:metabolism; D005260:Female; D020662:Guanine Nucleotide Exchange Factors / Q000096:biosynthesis*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D064067:Rho Guanine Nucleotide Exchange Factors; D014018:Tissue Distribution; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
D018797:Cell Cycle Proteins; D020662:Guanine Nucleotide Exchange Factors; D020033:Protein Isoforms; D064067:Rho Guanine Nucleotide Exchange Factors; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020764:cdc42 GTP-Binding Protein