ABSTRACT
To evaluate the effect and working mechanism of a newly developed anti-cancer drug, AG60 (acriflavine-guanosine compound, Taerim Pharm. Co. Seoul, Korea), histotologic, autoradiographic and electron microscopic studies were carried out. For the histologic study, each Ehrlich carcinoma cells (10(7) cells)-inoculated mouse was subcutaneously injected with saline (0.2 ml), 10 mg/kg of AG60, or 30 mg/kg of AG60, every other day, respectively. Animals were sacrified on the 14th day from the first injection, and tumor masses were fixed in 10% formalin solution. Tissue sections of the tumor were stained with hematoxylin and eosin. For the electron microscopic study, Ehrlich carcinoma (10(7) cells)-inoculated mice were subcutaneously injected every other day with saline (0.2 ml) or 30 mg/kg of AG60, respectively. The day after 7th injection (14th day), animals were sacrified, small piece of tumor masses were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde solution followed by fixation in 2% osmium tetroxide solution. Ultrathin sections were counter stained with uranyl acetate-lead citrate solutions, and observed with JEM 100CX electron microscope. For the autoradiographic study, each Ehrlich carcinoma (10(7) cells)-inoculated mouse was injected every day with 0.2 ml of saline, 5 mg/kg of AG60, or 30 mg/kg of AG60, respectively. The day following the last injection, each animal was given a single dose of 0.7 micricurie/g of methyl-3H-thymidine (Amersham Lab., England) through the tail vein. Seventy minutes after the thymidine injection, animals were sacrified, tumor masses were collected and fixed in 10% neutral formalin. Tissue blocks were washed, dehydrated, embedded and cut in 6 micrometer-thick sections. Deparaffinzied sections were dipped in the autradiographic emulsion E1 (Amersham Lab., England) and dried and stocked in the dark room. Filmed sections were exposured five weeks in the dark room, and were developed in the developer. Labeled indices (mean number of labeled cells per 100 cancer cells) and labeled grain indices (mean number of labeled silver grains per one cancer cell, and total granule numbers per every 100 cancer cell) were observed and calculated. The results were as follows : 1. On histological study, massive apoptosis were occured following the injection of AG60. Only small number of live cancer cells were observed. 2. On electron microscopic study, massive apoptotic figures including fragmentation of nuclei and cytoplasms, multiple nucleoli, condensation of nucleus and cytoplasm, deep invaginations and microcleft formations of nuclei, margination of heterochromatin along the inner nuclear membrane and microcleft , etc. were noticed. Giant cells represent the "tumor cell-tumor cell emperipolesis", and many of them seem to be in process of "cytolytic emperipolesis". 3. On autoradiographic study, labeled grains of 3H-thymidine were suppressed to only 11%~5% of control cancer cells following AG60 administrations. Discussed on the above experiments, it is suggested that severe suppression of DNA, RNA and protein syntheses by AG60 induce massive apoptosis of cancer cells. AG60 is expected as one of most effective anticancer drugs for the cytostatic therapy, the disease stabilization, the improved quality of life, the prolongation of life, and possibly the chemoprevention.