SH3BGRL3 Protein as a Potential Prognostic Biomarker for Urothelial Carcinoma: A Novel Binding Partner of Epidermal Growth Factor Receptor.
OBJECTIVE
Mass spectrometry-based biomarker discovery has clinical benefit. To identify novel biomarkers for urothelial carcinoma, we performed quantitative proteomics on pooled urine pairs from patients with and without urothelial carcinoma.


METHODS
Shot-gun proteomics using liquid chromatography-tandem mass spectrometry and stable isotope dimethyl labeling identified 219 candidate proteins. The potential implication of SH3 domain binding glutamic acid-rich protein like 3 (SH3BGRL3) was examined by immunoblotting of the urine (n = 13) and urothelial tumors (n = 32). Additional immunohistochemistry was performed on bladder cancer array (n = 1145) and correlated with tumor aggressiveness. Then, biologic functions and signaling pathways of SH3BGRL3 were explored using stable cell lines.


RESULTS
The detectable urine SH3BGRL3 in patients with urothelial carcinoma was positively associated with higher histologic grading and muscle invasiveness of urothelial carcinoma. SH3BGRL3 is expressed in 13.9% (159/1145) of bladder cancer cohort and is positively associated with muscle invasion (P = 0.0028). SH3BGRL3 expression is associated with increased risk of progression in patients with nonmuscle-invasive bladder cancer (P = 0.032). SH3BGRL3 expression is significantly associated with a high level of epidermal growth factor receptor (EGFR) in bladder cancer (P < 0.0001). SH3BGRL3 promotes the epithelial-mesenchymal transition, cell migration, and proliferation of urothelial carcinoma in vitro. SH3BGRL3 interacts with phosphor-EGFR at Y1068, Y1086, and Y1173 through Grb2 by its proline-rich motif, and activates the Akt-associated signaling pathway.


CONCLUSIONS
Evaluation of SH3BGRL3 expression status or urine content may identify a subset of patients with bladder cancer who may require more intensive treatment. SH3BGRL3 deserves further investigation as a cotargeting candidate for designing EGFR-based cancer therapies. Clin Cancer Res; 21(24); 5601-11. ©2015 AACR.
Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Cheng-Yao
CY
Chiang
Department of Pathology, Taipei Veterans General Hospital, Taipei, Taiwan.
Chin-Chen
CC
Pan
Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Hong-Yi
HY
Chang
Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Ming-Derg
MD
Lai
Department of Urology, National Cheng Kung University Hospital, Tainan, Taiwan.
Tzong-Shin
TS
Tzai
Department of Urology, National Cheng Kung University Hospital, Tainan, Taiwan.
Yuh-Shyan
YS
Tsai
Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Pin
P
Ling
Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Hsiao-Sheng
HS
Liu
Department of Nuclear Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
Bi-Fang
BF
Lee
Department of Urology, National Cheng Kung University Hospital, Tainan, Taiwan.
Hong-Ling
HL
Cheng
Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Department of Pathology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Chung-Liang
CL
Ho
Department of Chemistry, College of Sciences, National Cheng Kung University, Tainan, Taiwan.
Shu-Hui
SH
Chen
Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Department of Pathology, College of Medicine, National Cheng Kung University, Tainan, Taiwan. chownh@mail.ncku.edu.tw.
Nan-Haw
NH
Chow
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D014408:Biomarkers, Tumor; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D066246:ErbB Receptors / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000652:urine*; D008297:Male; D008958:Models, Molecular; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism / Q000652:urine; D011379:Prognosis; D011470:Prostatic Hyperplasia / Q000378:metabolism / Q000652:urine; D011485:Protein Binding; D020543:Proteome; D040901:Proteomics / Q000379:methods; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction; D001749:Urinary Bladder Neoplasms / Q000378:metabolism / Q000401:mortality / Q000473:pathology; D014571:Urologic Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism / Q000652:urine*
D048868:Adaptor Proteins, Signal Transducing; D014408:Biomarkers, Tumor; D047908:Intracellular Signaling Peptides and Proteins; D010446:Peptide Fragments; D020543:Proteome; C400565:SH3BGRL3 protein, human; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt