Effect Of Cell Growth And Cell Cycle Of Human Liver Cancer HepG-2 Cell Line By KSC And 10-HCPT

In the course of chemotherapy,clinical co-administration approach is often used by multi-direction,multi-target to eliminate tumors.10-HCPT as separate from the tree of Camptotheca acuminala Decne in anticancer strongest trace vegetable base,has been successfully used in some tumor treatment and prevention,and it has no cross resistance with other anticancer drugs.10-HCPT anticancer and blocking tumor cells topoisomerase ?(Topo-?).As topoisomerase ? specific inhibitors,its combination with Topo-? and DNA,blocking DNA recombination in the incision site,blocking RNA synthesis,interfere with the cell division cycle,provide a fracture and degradation effect on chromosome DNA,and adjust the metabolism of cells and so on many kinds of ways of anti-cancer,plays an anti-cancer effect through anti-oxidation,inducing tumor cell apoptosis,adjusting cell metabolism and so on.Kappa-Selenocarrageenan(KSC),the artificial synthesis selenide product on the basis of carrageenan,has significant anti-tumor activities.In this study,the effects of KSC and 10-HCPT alone or in combination on Hep G-2 cell were analyzed by MTT assay.The regression equation was established for IC50,while the q value was calculated to determine the effect of combination treatment.While combined with 1nmol/L 10-HCPT and 30mg/L KSC,the IC50 values reduced to 27.89mg/L and 0.15nmlo/L,respectively.The q values of KSC combined with 10-HCPT are between 0.85 and 1.15.After exposure to KSC and 10-HCPT for48 h,tumor cells were shrunken,rounded,intercellular spaces increased,detached and suspended in the culture medium.On the other hand,a small part of cells increased in cell volume,membrane ruptured and necrosis-like.The number of viable cells in combination group was less than the individual treatment group.After exposure for 48 h,Hep G-2 cells presented some typically morphologic features of apoptosis,including cell shrinkage,nuclear condensation,strongly compactfluorescent and formation of apoptotic bodies under fluorescence microscopy.However,there was no significant difference in the number of apoptotic cells between combination group and the individual treatment group.Cyclin A expression rate of control group was 52.2%,1nmol/L 10-HCPT,120mg/L KSC and 1nmol/L10-HCPT + 120mg/L KSC were 61.5%,89.5% and 91.1%,respectively.Chk2 expression rates of the above groups were 58.1%,91.3% and 92.2% respectively,that between combined group and KSC group no significant.Western blot results showed that all treated expression rates of Cdc25 A and Cdk2 were less than the control group,while with the combination group the lowest.KSC and 10-HCPT in combination inhibited the growth of Hep G-2 cells in an additive manner,and induced S phase arrest in the cell-cycle.The possible mechanism of S phase arrest may be that the combination treatment activates the S phase checkpoint,and Chk2 activity is activated with a catalytic activity of Chk2 by phosphorylation of Cdc25 A to promote its ubiquitination degradation and thus Cdk2 activation is suppressed,which will block the formation of Cdk2 and Cyclin A complex that lead to S phase arrest and hinder the process of cell-cycle.