Nucleases and adenosine deaminase in malignant and non-malignant lesions of the human thyroid

Abstract

IN the previous paper (Ayre, Goudie and Goldberg, 1968) we compared dehydrogenase enzyme patterns in normal, hyperplastic and neoplastic human thyroid tissue. In this communication we report our findings on nucleases in the same pathological material. MATERIALS AND METHODSThe same two series of thyroid glands studied previously were investigated for nuclease activity. In the first, 56 samples of human thyroid tissue were fractionated into 3 cytoplasmic preparations-mitochondria, microsomes and supernatant. These tissues were distributed as follows: normal (11), adenoma (10), thyrotoxic (20), cancer (7), Hashimoto's thyroiditis (7) and Hurthle-cell adenoma (1). The method of fractionation has already been described . From 3 normals and 1 cancer, only the supernatant could be obtained. The following enzyme activities were measured as previously described by Goldberg and Pitts (1966): alkaline and acid ribonuclease (alk. and acid RNAase, EC 2.7.7.16), deoxyribonuclease I (DNAase I, EC 3.1.4.5), deoxyribonuclease II (DNAase HI, EC 3.1.4.6) and adenosine deaminase (ADase, EC 3.5.4.4). ADase was measured only in the supernatant; the other enzymes were measured in each of the 3 fractions. Protein concentration was measured by the method of Lowry, Rosebrough, Farr and Randall (1951), and the wet weight of each tissue was accurately recorded shortly after collection. It was thus possible in each fraction to express the enzyme activity relative to the protein content of that fraction (specific activity), the weight of the tissue, and the percentage of the total cytoplasmic activity of that enzyme.In the second series, 18 samples of human thyroid were subjected to prolonged homogenisation, and a supernatant fraction was prepared from the homogenate in which the enzyme activities listed above were measured. The methods of tissue homogenisation and estimation of deoxyribonucleic acid-phosphorus (DNA-P) content of the homogenate were described in a previous publication (Goldberg, Goudie and Ayre, 1968) which gives other relevant information. As the protein content of the supernatant and the wet weight of the tissue were also measured, enzyme activities were expressed for the supernatant in relation to the protein content of that fraction, the wet weight of the tissue and the DNA-P content of the homogenate.

Proteolytic enzymes in adenocarcinomata of the human colon.

“…1). This validates the comparison between normal and malignant tissues at the two pH values chosen, a useful precaution when investigating an ill-defined enzyme or group of enzymes active over a wide pH range, since mouse ascites tumours have a pH proffle for ribonuclease which differs from that of normal mouse tissues (Colter, Kuhn and Ellem, 1961), and the pH activity curve for ribonuclease in hyperplastic human thyroid tissue was not identical with that of the normal gland (Goldberg and Goudie, 1968). The existence of a proteolytic enFyme similar to the cathepsin D of beef spleen (Press, Porter and Cebra, 1960) and of rabbit spleen (Lapresle andWebb, 1960, 1962) has been demonstrated in guinea-pig intestinal mucosa (Kregar, Turk and Lebez, 1967).…”

“…Support for this suggestion was not forthcoming from a subsequent study of human thyroid neoplasms (Goldberg and Goudie, 1968). More recently, investigations by Sylven (1968a and b) revealed a high content of degradative lysosomal enzymes, especially cathepsin B, in the interstitial fluid of solid mouse tumour transplants, and the author speculated that cellular detachment by proteolytic enzymes may play an important role in tumour invasiveness.…”

The Behaviour of Deoxyribonucleases of Rat Liver in the Course of Diethylnitrosamine- Induced Carcinogenesis

“…In most cases, however, biochemical studies with homogenates of experimental tumours and/or tumour bearing organs revealed an increase of acid and/or a decrease of alkaline DNase activity (7,8,13). Less consistent results were obtained with spontaneous blastomas (5).…”

Late Age- and Dose-Related Effects on the Proteome of Thyroid Tissue in Rats after ¹³¹I Exposure

“…Increased beta-2-microglobulin (B2M) expression was seen in thyroid cancer [32][33][34]. Increased enzymatic activity of ADA was seen for thyrotoxicosis, thyroid cancer, adenomas and thyroiditis [35]. Aberrant methylation patterns for serpin family B member 5 (SERPINB5) (together with TIMP3, RARB2, RASSF1, TPO and TSHR) were used to distinguish between papillary thyroid cancer (PTC) and normal thyroid tissue [36].…”