jectives : Measuring the total cellular DNA and BrdU content simultaneously by using the monoclonal antibody BrdU and propidium iodide (PI) has been possible. So it has been advanced that the making a correct diagnosis and the predicting a
prognosis in
cancer as well as the evaluation of the responses of anti-cancer therapy. We intended to exam new anticancer chemotherapeutic agent, retinoic acid (RA) which has been reported to show
antiproliferative effect and also differentiation-inducing effect on tumor cells, for the treatment
of the hepatocarcinoma prevailed in our country. This study was designed to probe beneficial
effects of RA for preventing tumor recurrence and secondary metastasis through the
application of it to recently wide spreaded chemoembolozation therapy in heaptomas.
Methods : A semi-logarithmic plot of the proliferation was made in Hep G2 cells, and the
changes of the proliferative activities from adding RA to the medium were evaluated in
according to various concentrations of it. After staining the Hep G2 cells with fluoroscence
conjugated anti-BrdU and PI, the tumor cell kinetics was analyzed and the effects of RA on
the changes of the kinetics were also evaluated in the univariate and bivariate distribution of
flowcytometric measurement of DNA content/BrdU incorporation.
Results : Hep G2 cells stained with FITC conjugated anti-BrdU and with propidium iodide
(PI), were analyzed in the distribution of bivariate BrdU/DNA content or univariate DNA
content to investigate the tumor kinetics. Data from this expreiments showed that actual
doubling time (Td) is 51 hrs, potential doubling tiem (Tpot) is 29 hrs, the mean DNA
synthesis time (Ts) is 9.3 hrs, the labelling index is 27.6%.
From the evaluation of the effects of RA, known to enhance the differentiation and inhibit
the growth of tumor cells on Hep G2 cells, RA inhibited the proliferation of Hep G2 cells
significantly and the inhibition lasted for 10 days. To understand the growth inhibition of RA
on Hep G2 cells in terms of tumor cell kinetics, bivariate BrdU/DNA content distributions
were analyzed. Early stage of culture (day 1) showed increase in S phase percentage of cell
and decrease in G0/G1 phase. But late stage of culture (day 4) show decrease in S phase
percentage of cell to minimum and increase in G0/G1 phase at either 1uM or 0.1uM
concentration of RA as compared with those of control. The influences on cell cycle and
the antiproliferative effect were more pronounced at 1uM than at 0.1uM concentration.
Conclusion : These results demonstrated that RA inhibits the proliferation of Hep G2 cells
and the antiproliferative effect is suggested to be driven from arresting cell cycle progression
from G0/G1 to S phase in tumor cell kinetics.
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