7345

UCHL1

ubiquitin carboxyl-terminal esterase L1 (ubiquitin thiolesterase);UCHL1;ubiquitin carboxyl-terminal esterase L1 (ubiquitin thiolesterase)

epididymis luminal protein 117|neuron cytoplasmic protein 9.5|ubiquitin C-terminal hydrolase|ubiquitin carboxyl-terminal hydrolase isozyme L1|ubiquitin thioesterase L1

4p14

protein-coding

BACKGROUND: Recently, it has been proven that protein gene product 9.5 (PGP9.5) hypomethylation might play an important role in re-expression of the PGP9.5 gene in gallbladder cancer. We previously examined the expression of PGP9.5 in primary colorectal cancer using immunohistochemistry and found that PGP9.5 expression is related to tumor progression and may be useful as a marker for invasive colorectal cancer. These results prompted us to examine the methylation status of the PGP9.5 gene in colorectal cancer. MATERIALS AND METHODS: The methylation status of the PGP9.5 gene in primary tumors derived from 49 patients with colorectal cancer using a quantitative methylation-specific polymerase chain reaction (qMSP) and the association between the methylation status and the clinicopathological findings was evaluated. RESULTS: An aberrant methylation of the PGP9.5 gene was detected in 36 out of 49 (73%) primary colon cancer samples. Subsequently, clinicopathological data were tested for their association with the methylation results. Lymph node metastasis was significantly associated with a lower frequency of methylation (p=0.029). CONCLUSION: These findings indicated that PGP9.5 was less frequently methylated in metastatic colorectal cancer, suggesting that PGP9.5 hypomethylation might play an important role in re-expression of the PGP9.5 gene in colorectal cancer.

Ubiquitin C-terminal hydrolase-L1 (UCH-L1) catalyses the hydrolysis of ubiquitin ester and amide mainly in neuronal cells. Recently it was proposed as a marker with a potential role in carcinogenesis. However, the molecular mechanism underlying the biological function of UCH-L1 in tumor cells is poorly understood. We found that UCH-L1 is highly expressed in non-small lung cancer cell line H157, having high invasive potential, and that the expression of UCH-L1 in tumor cells enhances their invasive potential in vitro and in vivo. UCH-L1 changes cell morphology by regulating cell adhesion through Akt-mediated pathway. Suppressing UCH-L1 expression by RNAi significantly suppressed the invasion in vitro and in vivo, and the activation of Akt and downstream mitogen activated protein kinases c-Jun N-terminal kinases and p38, but not ERK. In Akt-negative mutants, overexpression of UCH-L1 does not affect the invasion and migration capability of H157 cells. These results suggest that UCH-L1 is a key molecule to regulate tumor-cell invasion by upstream activation of Akt.

BACKGROUND: A proportion of men with prostate cancer will progress to develop metastatic disease involving the lymph-nodes and bone. To identify novel candidates associated with metastatic progression, we compared the proteomic profiles of LNCaP (lymph-node metastatic, androgen-dependant) and PC-3 (bone metastatic, androgen-independent), human prostate cancer cells. METHODS: Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), followed by electrospray ionisation tandem mass spectrometry (ESI-MS/MS), was used to identify differentially expressed proteins. Western blotting was used to validate the identity of any candidates. Immunohistochemistry was used to assess tissue expression. RESULTS: 2D-PAGE followed by ESI-MS/MS analyses identified the expression of glutathione S-transferase-pi (GST-pi) and protein gene product 9.5 (PGP 9.5) in PC-3 cells, but absent expression in LNCaP cells. PGP 9.5 expression in PC-3 cells was confirmed by Western blotting, in addition to expression in DU145 cells. Analysis of cell conditioned media showed that PGP 9.5 was secreted. Sequencing of the PGP 9.5 gene promoter region in bisulfite modified DNA, suggested that the regulation of expression involves promoter hypermethylation. RT-PCR analysis for Chromogranin A (ChA) mRNA (a marker of neuroendocrine cells), showed expression in PC-3 and DU145 cells but was undetectable in LNCaP cells. Immunohistochemistry localised PGP 9.5 expression exclusively within neuroendocrine cells and nerve fibres. CONCLUSIONS: Our unexpected finding that the neuroendocrine cell markers PGP 9.5 and ChA are expressed by PC-3 and DU145 cells, suggests that these cells may have been derived from metastatic adenocarcinomas which had undergone neuroendocrine differentiation or alternatively the expression occurred ectopically as a result of cell culture.

BACKGROUND: A proportion of men with prostate cancer will progress to develop metastatic disease involving the lymph-nodes and bone. To identify novel candidates associated with metastatic progression, we compared the proteomic profiles of LNCaP (lymph-node metastatic, androgen-dependant) and PC-3 (bone metastatic, androgen-independent), human prostate cancer cells. METHODS: Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), followed by electrospray ionisation tandem mass spectrometry (ESI-MS/MS), was used to identify differentially expressed proteins. Western blotting was used to validate the identity of any candidates. Immunohistochemistry was used to assess tissue expression. RESULTS: 2D-PAGE followed by ESI-MS/MS analyses identified the expression of glutathione S-transferase-pi (GST-pi) and protein gene product 9.5 (PGP 9.5) in PC-3 cells, but absent expression in LNCaP cells. PGP 9.5 expression in PC-3 cells was confirmed by Western blotting, in addition to expression in DU145 cells. Analysis of cell conditioned media showed that PGP 9.5 was secreted. Sequencing of the PGP 9.5 gene promoter region in bisulfite modified DNA, suggested that the regulation of expression involves promoter hypermethylation. RT-PCR analysis for Chromogranin A (ChA) mRNA (a marker of neuroendocrine cells), showed expression in PC-3 and DU145 cells but was undetectable in LNCaP cells. Immunohistochemistry localised PGP 9.5 expression exclusively within neuroendocrine cells and nerve fibres. CONCLUSIONS: Our unexpected finding that the neuroendocrine cell markers PGP 9.5 and ChA are expressed by PC-3 and DU145 cells, suggests that these cells may have been derived from metastatic adenocarcinomas which had undergone neuroendocrine differentiation or alternatively the expression occurred ectopically as a result of cell culture.

PURPOSE: Renal cell carcinoma (RCC) accounts for 2% to 3% of all malignancies. It represents one of the most radiation- and chemotherapy-resistant tumors and surgical resections are only effective in organ-defined disease. However, RCC is an immunogenic tumor with response rates to immunotherapies between 10% and 20% of the treated patients. Due to the currently inefficient therapies and the low 5-year survival rates of RCC patients, novel diagnostic, prognostic, and therapeutic markers are urgently needed for this disease. EXPERIMENTAL DESIGN: Proteome-based approaches were used to identify (a) differentially expressed proteins in RCC compared with normal kidney epithelium and (b) proteins that are able to induce an antibody response in RCC patients. Based on these experiments, a promising candidate was subsequently validated by reverse transcription-PCR, Western blot analyses, and immunohistochemistry. In addition, functional assays were done in generated transfectants. RESULTS: The ubiquitin COOH-terminal hydrolase L1 (UCHL1) was found to be differentially expressed in both RCC lesions and RCC cell lines and immunoreactive using patients' sera. UCHL1 expression was often down-regulated in primary RCC when compared with normal kidney epithelium but dependent on the RCC subtype, the von Hippel-Lindau phenotype, and the tumor grading. Moreover, the frequency and the level of UCHL1 expression were higher in metastases when compared with primary RCC lesions. Gain-of-function transfectants exhibited a significant higher proliferation and migration rate than UCHL1-negative RCC cells. CONCLUSIONS: UCHL1 expression seems to be associated with the metastatic phenotype of RCC and therefore might serve as potential biomarker for the diagnosis and prognosis of RCC patients.

Proteomic differential display analysis was performed on human renal cell carcinoma cell SN12C clones having different metastatic potentials by using 2-DE and LC-MS/MS. The SN12C cell clones were SN12C parent cell line, SN12C-clone 2, SN12C-clone 4, and SN12C-PM6. The SN12C parent cell line was established from an HRCC surgical specimen. SN12C-clone 4 has lower, and SN12C-clone 2 and SN12C-PM6 have higher metastatic potential than SN12C parent cells. We found eight protein spots whose expression level was different between low metastatic clones and high metastatic clones. The protein expression of three appeared to be higher in high metastatic clones than low metastatic clones, and that of other five protein spots appeared to be lower in high metastatic clones than low metastatic clones. These spots were selected, digested and analyzed by LC-MS/MS analysis, and they were identified by peptide sequencing tag. In high metastatic potential clones, two isoforms of ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCH-L1) were downregulated. These results suggest that UCH-L1 expression seems to be associated with the metastatic potential of HRCC SN12C cell clones.