Chloroquine Mediated Alterations in Mammalian Cell Metabolism and Viral Replication 1

Abstract

Chloroquine is an effective antimalarial drug that has also been successfully employed clinically in treating lupus erythematosus (1), as well as rheumatoid arthritis (2). A number of studies performed to examine the biological effects of chloroquine have revealed a diversity of activities. Some of the drug effects included a stabilization of lysosomal membranes (3), an activation of E. coli tyrosine transfer ribonucleic acid (RNA) (4), binding to bacterial deoxyribonucleic acid (DNA) with an alteration of the polymerase reactions (5-8) and an inhibition of a number of metabolic enzymes such as alcohol dehydrogenase (9) and succinic dehydrogenase (10). There is a relative paucity of information describing the effects of chloroquine on mammalian cell metabolism and no information on the effects of this drug on the replication of animal viruses. Since chloroquine is employed clinically as well as for investigative purposes, this study sought to examine the effect of this drug on mammalian cell biosynthetic processes and to survey its effect on the replication of several unrelated viruses.

Materials and Methods. Cells. HeLa cells maintained in 16-oz prescription bottles as stationary monolayers were periodically dispersed by trypsinization as described (11) and distributed to 2-oz French square bottles (A. H. Thomas Co.) 18-24 hr prior to the onset of each experiment. All experiments to measure the rates of protein, RNA, and DNA synthesis and all virus growth studies were performed using these smaller monolayers, containing 2 to 5 × 10⁶ cells/bottle. A continuous rat heart cell line, used to quantitate vaccinia and herpes virus, was similarly treated.

Medium. Growth medium consisted of Eagle's medium (12) in Hanks' balanced salt solution (BSS) (13), supplemented with 10% newborn calf serum (N. Am. Biological), 10% tryptose phosphate broth, Aureomycin (50 μg/ml), neomycin (75 μg/ml) and Mycostatin (25 μg/ml).