Experimental Study On Combined Antitumor Effect Of 10-Hydroxycamptothecine (10-HCPT) And Sodium Selenite

Objects: to investigate the combined effect of combined hydroxy- camptothecine and sodium selenite on H-22 mouse hepatoma cells in vitro and in vivo.Methods: MTT assay was used to determine the growth inhibition of hepatoma H-22 cells or the experimental mice hepatoma by using hydroxycamptothecine alone,sodium selenite alone or the both. Cell cycle was analyzed by flow cytometry. Cell morphology was detected by light microscope and transmission electron microscope. And immunocytochemistry were used to evaluate the expression of Caspase3,Caspase9,Bax,Bcl-2.Results:1. MMT shows that inhibition rates of H22 cells treated with 10-HCPT and sodium selenite combined used at the same dose of 6.25μmol/l, 12.5μmol/l, 25μmol/l, 50μmol/l were 14.04%, 38.63%, 59.90% and 63.12% respectively. And the combination of 10-HCPT and soudium selenite more significantly inhibited the proliferation of H22 cells than the two drags did alone at the same concentrations.The IC50 values of 10-HCPT and soudium selenite were respectively 102.44μmol/l and 65.79μmol/l. And the IC50 value of combination treatment was 24.23μmol/l.Beacause the two drugs CI values are less than 1. They demonstrated synergistic activity.2. The results of H22 tumor bering mice tests approved that the inhibition rates of mice hepatuma treated with 10-HCPT and sodium selenite at the closeof 12.5mmol/kg were 20.97% and 25.78% respectively and IC values were 56.45μmol/kg and 34.74μmol/kg. And that the inhinbition rate of mice hepatuma treated with combination treatment was 49.68% and IC values 12.82μmol/kg.3. After dealing 48 hours on H22 cells with 10-HCPT and sodium selenite respectively or simultanecnsly morphologic changes of apotosis with chromation margination, karyopy, knosis, karyorrhexis, a poptotic body were found by the light and election microscope.4. Flow cytometrery analysis results showed that 10-HCPT made H22 cells S block in the cell -cycle and the percentage of S phrase increased while sodium slenite made the percentage of G2/M phrase increased. When the two drags used together, they made the percentage of S phase and G2/M increated more siynificantly than the control group.5. The results of immunohistochemistry shows that all treated expression rates of Caspase3, Caspase9 and Bax were more than the models, while these of Bcl-2 were less than the models. The espression rates of combined was less than the two drugs effected alone.Conclusions:Alone or in combination sodium selenite and 10-HCPT could inhibit the growth of human hepatoma cells effectively .The combination of them showed synergistic effect at relatively high concentration.Although they had a different antitumor mechanism, the two drugs had similar effect on induction of cell death,arrest of cell cycle, upgrade of the expression of apoptosis-related protein and induction of the expression of differentiation-metastasis related protein.The combination of the two drugs is practical according to the compose principle of the combination chemotherapy regimens. There are good prospect of combined use of sodium selenite and 10-HCPT for tumor.