A Study On Radiosensitivity Of β-elemene To Human Cervical Carcinoma Of Hela Hypoxic Cell

Objective: This study aim to research on the radiosensitivity of β-elemene tohuman cervical carcinoma of Hela hypoxic cell,discuss the relationship with HIF-1α,VEGF protein, mRNA expression and radiation sensitivity.Methods:1.MTT assay growth inhibition rate of β-elemene with different concentrations(12.5μg/ml,25μg/ml,50μg/ml,100μg/ml,200μg/ml,400μg/ml) on Hela human cervicalcancer cell.2.Observed cloning efficiency of normoxic and hypoxic groups, containingdifferent drug concentrations（0μg/ml,10μg/ml,20μg/ml）of β-elemene and at differentirradiation doses (0Gy,2Gy,4Gy,6Gy,8Gy).3. Immunocytochemistry methods observed the expression of HIF-1α and VEGFprotein in normoxic cells in the control group, hypoxic cells in the control group,hypoxia radiotherapy (5Gy) group, hypoxia drug (20μg/ml) group, hypoxia combinedgroup (5Gy+20μg/ml).4.RT-PCR methods detected the expression of HIF-1α and VEGF mRNA innormoxic cells in the control group, hypoxic cells in the control group, hypoxiaradiotherapy (5Gy) group, hypoxia drug (20μg/ml) group, hypoxia combined group(5Gy+20μg/ml).Results:1.The24h IC50value to Hela cells of β-elemene is80μg/ml.2.In the absence of irradiation dose,cell viability has no significant difference(P>0.05) under normoxic group and hypoxic group.But with the increasing highradiation doses,cell vibility was significantly decreased (P<0.01).At the same dose, cellviability under hypoxic group was higher than normoxic group (P <0.01).β-elemene has significant inhibitory Effect on Hela cells under the normoxic and hypoxictreatment,with the increase of drug concentration, cell viability gradually decreased(P<0.01).3.The expression of HIF-1α protein in each experimental group: hypoxiaradiotherapy group had a significantly higher expression (P<0.01), hypoxia combinedgroup was significantly lower (P<0.01),There is no significant difference betweenhypoxia drug group and hypoxic cells in the control group (P>0.05), Every hypoxiagroup had a significantly higher protein expression than normoxic cells in the controlgroup (P <0.01).VEGF protein expression in each group was the same to HIF-1α proteinexpression.4.The expression of HIF-1α mRNA in each experimental group: hypoxiaradiotherapy group had a significantly higher expression (P<0.01), hypoxia combinedgroup was significantly lower (P<0.01),There is no significant difference betweenhypoxia drug group and hypoxic cells in the control group (P>0.05), Every hypoxiagroup had a significantly higher mRNA expression than normoxic cells in the controlgroup (P <0.01).VEGF mRNA expression in each group was the same to HIF-1α mRNAexpression.Conclusion:1.β-elemene could significantly inhibit the proliferation of Hela cells, IC50valueis80μg/ml, proliferation inhibition rate increased along with increased concentration ofβ-elemene.2.β-elemene under the low cytotoxic concentration has radiosensitivity to Helacells both of normoxic group and hypoxic group.As the drug concentrationincreased,the radiosensitization effect increased gradually.3.The cell viability of Hela cells under hypoxic group was significantly higherthan normoxic group,showing anti-radiation phenomenon.4.Neither hypoxia drug group nor hypoxic cells in the control group hassignificantly influence on the expression of protein and mRNA of Hela cells.Hypoxiaradiotherapy group had significantly higher protein and mRNA expression.Hypoxiacombined group was significantly lower. Every hypoxia group had a significantlyhigher protein and mRNA expression than normoxic cells in the control group.5.β-elemene combined with radiotherapy could significantly reduced the expression of HIF-1α，VEGF protein and mRNA of Hela hypoxic cell.Also associatedwith inhibition of angiogenesis.So we can speculate that β-elemene increased theradiosensitivity effect on Hela hypoxic cells through down-regulating the expression ofHIF-1α and VEGF. HIF-1α and VEGF may be the targets of the radiosensitivity ofβ-elemene.