Molecular cloning of rat precursor cathepsin H and the expression of five lysosomal cathepsins in normal tissues and in a rat carcinosarcoma

Functional interface between cathepsins and growth factors in the kidney development

During kidney development many proteases are involved with the remodeling process of the extracellular matrix (ECM) during nephrogenesis. This study used embryonic kidneys culture, tridimensional cell culture, and reverse transcriptase-polymerase chain reaction (RT-PCR) techniques in order to investigate the expression of cathepsins S (CS) and cathepsin H (CH) during metanephrogenesis and their functional interface with hepatic growth factor (HGF) and nerve growth factor (NGF). Results have shown that cathepsin S has been expressed early than the cathepsin H in the nephrogenesis. NGF antibody in the embryonic kidney cultures, in a dose-dependent mechanism inhibited the CS but not CH genic expression by RT-PCR. The tridimensional cells culture with MDCK and IMCD cells confirmed the interface between HGF and CS and CH once their inhibitors added to the culture, reduced the fancy branching formation induced by this growth factor. In summary, this study suggests that CS and CH are differently expressed during nephrogenesis and also that they are involved with the tubulogenesis probably mediating specific growth factors such as NGF and HGF.

Marked increases in cathepsin B and L activities distinguish papillary carcinoma of the thyroid from normal thyroid or thyroid with non-neoplastic disease

Cathepsin B (CB) and cathepsin L (CL) are cysteine endopeptidases involved in the processing of thyroglobulin (Tg) in the normal thyroid. As thyroglobulin expression is frequently altered in thyroid carcinomas, we have analyzed 42 human thyroid tissues from 40 patients to study the effect of malignant transformation an the expression of these endopeptidases. Our samples included 18 cases of papillary carcinoma (of which 10 also had matched adjacent normal thyroid tissue), 6 cases of normal thyroid from autopsy patients, 1 case of follicular carcinoma, 2 cases of medullary carcinoma, 2 cases of follicular adenoma, 3 cases of Hashimoto's thyroiditis (HT) and 10 samples from 8 patients with multi-nodular goiter (MNG). Enzyme-specific activities were increased 15-fold for CB and 9-fold for CL in papillary carcinoma compared with normal adjacent thyroid tissue or normal thyroid from autopsies. CB mRNA content was also markedly increased in papillary carcinoma compared with normal thyroid, primarily due to elevated levels of the 2.2-kb CB mRNA transcript. In thyroids with nonneoplastic diseases, including MNG and HT, there was no significant increase in either CB or CL enzyme activities nor CB mRNA levels compared with normal thyroids from non-cancer cases. Immunohistochemical studies on papillary carcinomas revealed increased CB staining in papillary carcinoma cells, with prominent staining close to the basement membranes of many of the neoplastic cells. Our observations suggest that CB and CL enzyme activities are potentially useful new biochemical markers for distinguishing papillary carcinoma of the thyroid from non-neoplastic thyroid disease.

Cysteine endopeptidase activity levels in normal human tissues, colorectal adenomas and carcinomas

We have assayed cysteine endopeptidase activities in 17 types of normal human tissue and in matched sets of colorectal mucosa, adenoma and carcinoma samples. Our data indicate that cathepsin B enzyme levels vary 70-fold and cathepsin L enzyme levels vary 20-fold from one normal tissue to another. Cathepsin B specific activity in normal tissues fell into 3 categories. High activity, with a mean of 156.7 +/- 41.5 nmoles min-1 mg-1 protein, was measured in liver, thyroid, kidney and spleen; intermediate activity, with a mean of 60.2 +/- 8.3 nmoles min-1 mg-1 protein, was measured in heart, colon, adrenal and lung; and low activity, with a mean of 18.4 +/- 9.7 nmoles min-1 mg-1 protein, was measured in prostate, testis, nerve, stomach, pancreas, brain, skeletal muscle, skin and breast. Cathepsin L specific activity fell into 2 categories. High activity, with a mean of 51.1 +/- 4.9 nmoles min-1 mg-1 protein, was measured in thyroid, liver and kidney; and low activity, with a mean of 11.4 +/- 5.5 nmoles min-1 mg-1 protein, was measured in spleen, colon, heart, adrenal, lung, testis, brain, nerve, skin, stomach, pancreas, skeletal muscle, prostate and breast. Our characterization of these enzyme levels provides a reference standard for normal cathepsin B and L activities in human tissues that should enhance the detection of their deregulation in disease states. For example, in studies of colorectal carcinoma and normal mucosa, we observed a significant tumor-specific increase in cathepsin B and L activities with particularly high activity levels in earlier (Dukes' A and B) compared to later (Dukes' C and D) stages of colorectal cancer. In contrast, adenomas from colorectal cancer patients expressed normal levels of cathepsin B activity, providing evidence that the increase in expression of cathepsin B may be a sensitive marker for progression from the pre-malignant to the malignant state in the development of colorectal cancer.

The structure of the mouse cathepsin B gene and its putative promoter

The mouse cathepsin B gene and its flanking regions were cloned and characterized. The gene contains 10 exons and 9 introns spanning about 20 kb. Although the exon-intron organization of the mouse cathepsin B gene showed some similarity to the rat cathepsin H and L genes, significant differences were found. In particular, the highly conserved sequence that contains the catalytically active cysteine in these genes is split at different sites by an intron. As with other thiol proteinases, there is no obvious correspondence between the coding exons and structural or functional units within preprocathepsin B. These results suggest that the lysosomal thiol proteinase genes are evolutionarily ancient and that intron shifting has occurred subsequent to their divergence from a common ancestral form. The 5'-flanking region and exon 1 sequences in the mouse cathepsin B gene have a high GC content of approximately 72%. The 5'-flanking region also contains several potential Sp1 binding sites, but lacks TATA and CAAT motifs. These characteristics suggest that cathepsin B is a "housekeeping" gene and its transcription may be controlled by multiple transcription factors, including Sp1.