Acid ribonuclease activity of hepatoma cells.

Activities of intracellular RNase of the liver cytoplasm, normal liver cells exposed to 3’Me-DAB and heaptoma cells, have been studied in correlation with the contents of RNA and DNA and morphologic changes of the cells with or without treating RNase. The data showed that in hepatoma cells the intracellular acid RNase activity decreases with the decrease of RNA and unchanged DNA contents and alkaline RNase activity. Morphologic observation proved that hepatoma cells show a small low massed vesicular or vacuolar endoplasmic reticulum having ribosomes. For the exposure to RNase the hepatoma cells proved to be much less resistant comparing to normal liver cells. The former lost the granules and was destroyed in its endoplasmic reticulum, whereas the latter retained ribosomes and ER. From these experiments it has been speculated that acid RNase in the cell may be involved in RNA synthesis and alkaline RNase in RNA decompostition, though the effect of the difference in concentration in the case given RNase experimentally can not be neglected. ∗PMID: 14032742 [PubMed indexed for MEDLINE] Copyright c ©OKAYAMA UNIVERSITY MEDICAL SCHOOL Acta Med. Okayama 16, 15-28 (1962) ACID RIBONUCLEASE ACTIVITY OF HEPATOMA CELLS Tetsuo KIMOTO, Kenji HAYASHI, and Hisashi MONDEN Department of Pathology, Okayama University Medical School, Okayama '(Director: Prof. Satimaru Seno) Received for publication, January 13, 1962 A correspondence of the activity of intracellular ribonuclease (RNase) with cell growth has been noted by several investigators (BRODY\ GROTH, BAKER, and CANNON , and the suggestion has been made by many workers that intracellular RNase may have a ribonucleic acid (RNA) synthetic activity (BRODY\ REDDI\ HEPPEL, WHITEFELD, and MARKHAM) as well as the well-known activity of disintegrating RNA, with which RNase may be functioning to regulate the metabolism of RNA keeping it in some level according to the intracellular environment. In the living cell, however, RNase is safely contained in cytoplasm without giving any abnormal disintegrating activity to RNA. Concerning the liver cells its cytoplasm contains at least two RNases, an acid and alkaline RNases (de LAMIRANDE., ALLARD., da COSTAl\., CANTERO and ROTH6,7,B,9). Cancer cells also have a quantity of two sorts of RI~ase like normal cells showing the close correlation with the nucleic acid metabolism as has been studied cytochemically by LEDOUX10,ll,J2,J:I, BRODy14, REID, and LOTZ16, and DAousT. Recently, it has been demonstrated that RNase given from outside penetrate into the cell disturbing the metabolism of RNA and inducing various morphologic and biochemical changes, like abnormal mitosis, destruction of endoplasmic reticulum and granules, disturbed desoxyribonucleic acid (DNA) and protein syntheses17, lB. And yet it has been demonstrated that cancer cells are especially susceptible to RNase given from outside and it is supposed that the permeability to RNase in each cell is due to the contents of RNase, i. e. the smaller the quantity of RNase in a cell the better is the permeability to RNase. (LEDOUX et al.) From these observations it is reasonablly expected that RNase decrease when the normal cells turn to cancer cells. From this view point the authors observed RNase activity in both of normallliver and hepatoma tissue, with referring to the amount of RNA and DNA.