Enhanced acid protease activity of lysosomes from papillary thyroid carcinoma

Abstract

In vitro lysosomal acid protease activity was studied in human papillary thyroid carcinoma (n = 13). As a control, morphologically normal thyroid tissue from the same patient was used in each individual case of carcinoma. Although a marked variation may be observed between individual cases, each examined papillary thyroid carcinoma showed significantly greater activity of acid proteases, both per unit weight of wet thyroid tissue and per unit of lysosomal proteins, in comparison to the corresponding control (range, 24%-248%). In conclusion, it is suggested that enhanced proteolytic activity of lysosomal acid proteases in papillary carcinoma is probably a result of disturbance in catabolic degradation of the thyroglobulin molecule in malignantly transformed thyroid tissue.

Altered Terminal Glycosylation of Thyroglobulin in Papillary Thyroid Carcinoma

“…In most differentiated thyroid carcinoma the ability to concentrate iodine is greatly decreased (Valenta et al, 1968) and the Tg molecule from malignant tissue in both poorly iodinated (Thomas-Morvan et al, 1974;Sinadinovié et al, 1980) and has a low hormone content Rolland et al, 1972). Furthermore, it was observed that in thyroid carcinoma the activity and solubilization of thyroid peroxidase is altered (Fragu and Nataf, 1977;Neary et al, 1978), Tg transfer from thyrocite into the circulation is increased (Van Herle and Uller, 1975), TSH responsiveness of malignant tissue is altered (Field et al, 1976;Thomas-Morvan et al, 1982) and more recently it was found that the activity of acid lysosornal proteases is enhanced in carcinoma (Sinadinovié et al, 1989).…”

Measuring Thyroglobulin Concentrations in Patients with Differentiated Thyroid Carcinoma

“…However, due to malignant transformation of thyroid follicular cells, the structure of Tg (especially the carbohydrate component) can be changed (7) together with alterations in the secretion mechanism (8). Epitope mapping on the Tg molecule has shown the existence of six different antigenic regions to which different thyroglobulin-specific antibodies (TgAb) can bind (9, 10), most probably due to differences in Tg molecules secreted from malignantly changed thyroid cells (9,(11)(12)(13).…”

Acid Phosphatase Activity in Human Breast Tumors

“…Acid phosphatase (AP) has also been used to monitor cell death and cell lysis [5,6,7,8]. Activities of lysosomal hydrolases were demonstrated to be more marked in cancer cells than in homologous normal tissue [9,10]. Ductal carcinoma in situ (DCIS), also known as intraductal carcinoma, is characterized by proliferation of presumably malignant epithelial cells within the mammary ductal-lobular system, without light microscopic evidence of invasion into surrounding stroma [11].…”