Hypoxia-inducible protein 2 (HIG2), a novel diagnostic marker for renal cell carcinoma and potential target for molecular therapy.
To identify molecules to serve as diagnostic markers for renal cell carcinoma (RCC) and as targets for novel therapeutic drugs, we investigated genome-wide expression profiles of RCCs using a cDNA microarray. We subsequently confirmed that hypoxia-inducible protein-2 (HIG2) was expressed exclusively in RCCs and fetal kidney. Induction of HIG2 cDNA into COS7 cells led to secretion of the gene product into culture medium and resulted in enhancement of cell growth. Small interfering RNA effectively inhibited expression of HIG2 in human RCC cells that endogenously expressed high levels of the protein and significantly suppressed cell growth. Moreover, addition of polyclonal anti-HIG2 antibody into culture medium induced apoptosis in RCC-derived cell lines. By binding to an extracellular domain of frizzled homologue 10 (FZD10), HIG2 protein enhanced oncogenic Wnt signaling and its own transcription, suggesting that this product is likely to function as an autocrine growth factor. ELISA analysis of clinical samples identified secretion of HIG2 protein into the plasma of RCC patients even at an early stage of tumor development, whereas it was detected at significantly lower levels in healthy volunteers or patients with chronic glomerulonephritis. The combined evidence suggests that this molecule represents a promising candidate for development of molecular-targeting therapy and could serve as a prominent diagnostic tumor marker for patients with renal carcinomas.
Togashi
Akira
A
Laboratory of Molecular Medicine, Human Genome Center, Institute of Medical Science, The University of Tokyo, Japan.
Katagiri
Toyomasa
T
Ashida
Shingo
S
Fujioka
Tomoaki
T
Maruyama
Osamu
O
Wakumoto
Yoshiaki
Y
Sakamoto
Yoshiro
Y
Fujime
Makoto
M
Kawachi
Yoshio
Y
Shuin
Taro
T
Nakamura
Yusuke
Y
D000818:Animals; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D019556:COS Cells; D002292:Carcinoma, Renal Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D048708:Cell Growth Processes / Q000502:physiology; D002522:Chlorocebus aethiops; D045325:HCT116 Cells; D006367:HeLa Cells; D006801:Humans; D007680:Kidney Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D014162:Transfection; D015854:Up-Regulation
D014408:Biomarkers, Tumor; C405620:HILPDA protein, human; D009363:Neoplasm Proteins