1514

CTSL

cathepsin L;CTSL;cathepsin L

cathepsin L1|major excreted protein

9q21.33

protein-coding

It is recognized that many cancer cells secrete cathepsin L to degrade the components of extracellular matrices and basement membranes, thus promoting tumor invasion and metastasis. However, very little information is available concerning the secreted forms of cathepsin L and their possible role in human cancer. We initially demonstrated that approximately 10-fold higher mature cathepsin L activity was secreted in a medium of human fibrosarcoma (HT 1080) cells, compared with their intracellular activity. A 32-kDa major-activity band, together with a 41-kDa faint-activity band, was detected in the medium by our newly developed gelatin zymography. The two forms were further confirmed to be cathepsin L by immunoblot analysis. Both were apparently secreted directly from the cells, as neither was affected when the cells were cultured in the presence of various kinds of proteinase inhibitors. Human tumor necrosis factor-alpha (TNF-alpha) stimulated not only the production of the 32-kDa cathepsin L, but also its secretion. Moreover, the 32-kDa cathepsin L activities in 3 colon and 2 lung cancer tissues were significantly higher than in normal tissues. Based on the foregoing, there are good reasons to speculate that the 32-kDa cathepsin L found in HT 1080 cell medium is involved in cancer invasion and metastasis.

It is recognized that many cancer cells secrete cathepsin L to degrade the components of extracellular matrices and basement membranes, thus promoting tumor invasion and metastasis. However, very little information is available concerning the secreted forms of cathepsin L and their possible role in human cancer. We initially demonstrated that approximately 10-fold higher mature cathepsin L activity was secreted in a medium of human fibrosarcoma (HT 1080) cells, compared with their intracellular activity. A 32-kDa major-activity band, together with a 41-kDa faint-activity band, was detected in the medium by our newly developed gelatin zymography. The two forms were further confirmed to be cathepsin L by immunoblot analysis. Both were apparently secreted directly from the cells, as neither was affected when the cells were cultured in the presence of various kinds of proteinase inhibitors. Human tumor necrosis factor-alpha (TNF-alpha) stimulated not only the production of the 32-kDa cathepsin L, but also its secretion. Moreover, the 32-kDa cathepsin L activities in 3 colon and 2 lung cancer tissues were significantly higher than in normal tissues. Based on the foregoing, there are good reasons to speculate that the 32-kDa cathepsin L found in HT 1080 cell medium is involved in cancer invasion and metastasis.

OBJECTIVE: To investigate the clinicopathological and prognostic significance of the expression of cathepsin L and its inhibitor headpin, in oral squamous cell carcinoma. DESIGN: Immunohistochemical studies were performed on 56 oral squamous cell carcinoma samples. We evaluated the relationship between cathepsin L and headpin expression versus patients' clinicopathological factors and survival. RESULTS: The group that was positive for cathepsin L expression tended to have positive metastatic neck lymph nodes and a poorer prognosis. Headpin expression was not related to metastasis or prognosis. Well differentiated squamous cell carcinoma had higher levels of headpin expression compared with poorly differentiated squamous cell carcinoma. CONCLUSION: Cathepsin L expression is related to the invasive and metastatic potential of oral squamous cell carcinoma.

OBJECTIVE: To clone cathepsin L (CTSL) gene and construct the eukaryotic expression plasmid pcDNA3.1-CTSL and study the relationship between CTSL and invasion and metastasis in ovarian cancer cells in vitro. METHODS: The total RNA was extracted from the ovarian cancer tissue and the intact cDNA of CTSL was applied by reverse transcription (RT)-PCR. The product of RT-PCR was cloned to pMD18-T vector, and subcloned to pcDNA3.1 vector. It was tested by the enzymation and DNA sequencing. The eukaryotic expression plasmid of CTSL was introduced into HO8910 cells by liposome transfection reagent. RT-PCR was used to confirm the recombinant plasmid DNA integrated with the genomic DNA of HO8910 cells. Western blot was used to confirm the CTSL protein expression in positive clones cells. The cell growth curves, clonogenicity efficiency were observed. The cell cycles were measured by flow cytometer. The ability of invasion, metastasis and adhesion of ovarian cancer cells were detected by the matrigel invasion assay, transwell migration assay and adhesion assay, respectively. RESULTS: The results from restrictive enzyme analysis and sequencing showed that the CTSL gene was successfully inserted into pcDNA3.1. Result from RT-PCR and western blot showed that the ovarian cancer cells which transfected by recombinant plasmid could express CTSL gene and protein. There was no difference between HO8910-CTSL and HO8910-pcDNA3.1 cells in proliferation and adhesion ability (0.16 +/- 0.04 versus 0.19 +/- 0.04) of the cells (P > 0.05). There was difference between HO8910-CTSL and HO8910-pcDNA3.1 cells in matrigel invasion ability (0.34 +/- 0.18 versus 0.17 +/- 0.04) and metastasis ability (1.252 +/- 0.114 versus 0.486 +/- 0.027) of cancer (all P < 0.05). CONCLUSION: CTSL maybe increase the ability of invasion and metastasis of ovarian cancer cells in vitro, which may be a molecular target of blocking invasion and metastasis of ovarian cancer.

Cysteine cathepsins (CTSs) are involved in the degradation and remodeling of the extracellular matrix and are associated with cellular transformation, differentiation, motility and adhesion in cancer development. Previous studies indicate that CTSs may be involved in ovarian cancer invasion and metastasis. However, due to the lack of large sample clinical studies and direct experimental evidence for the relationship between the expression of CTSs and invasion and metastasis, the diagnostic and prognostic value of CTSs in ovarian cancer progression has not been elucidated. In the present study, we observed that expression levels of CTSB, CTSL and CC in malignant ovarian tumors were significantly higher than the expression levels in benign tumors and normal ovarian tissues, yet their associations with clinicopathological features varied. In particular, CTSL was related to lymph node metastasis, CC was related to liver metastasis and omental metastasis, and CTSB and CTSL expression levels were found to be independent prognostic factors in ovarian cancer. Further study indicated that the serum level of CTSL was significantly higher in patients with ovarian malignant tumors than the levels in benign tumors and healthy controls, and the levels were elevated in low grade and advanced stage compared to the levels in high grade and early stage disease, suggesting that the serum level of CTSL may be a useful serum marker for the diagnosis of ovarian cancer. Furthermore, the expression of CTSL in ovarian cancer cells can greatly enhance the ability of cell invasion and metastasis, although no change was observed for cell adhesion. Taken together, we demonstrated that the overexpression of CTSL is involved in tumor invasion and metastasis, and the CTSL level in serum may be a marker for invasion and metastasis in ovarian cancer.