The Study Of The Effect Of DOX On The Intracellular Concentration Of Calcium Of MG-63 And MG-63/DOX Cells In Vitro

Backgroud Osteosarcoma is the most common type of bonemalignant tumor. Treatment of osteosarcoma includes surgery,chemotherapy, radiotherapy and Integrated treatment. Neoadjuvantchemotherapy was proposed by Rosen in 1982, which has becamethe standard therapeutic approach. But multidurg resistance tochemotherapeutic drugs is a major obstacle to effective treatment ofosteosarcoma. Calcium is a very important factor in life of cells andregulates numerous physiological cellular phenomena as a secondmessenger as well as triggering pathological events such as cellinjury and death. Objective To study the effect of doxorubicin on theintracellular concentration of ca2+ of MG-63 and MG-63/DOX cells invitro determine wheather the change of intracellular concentration ofca2+ can cause the formation of MDR in osteosarcoma. Method In this study MG-63 and MG-63/DOX cells aredivided into four groups, control, VER, DOX, DOX and VER group,in order to observe the change of the intracellular concentration of ca2+and ca2+ channel of MG-63 and MG-63/DOX cells by lscm and patchclamp technique. The fluorescence intensity of intracellular ca2+ andthe current of both MG-63 and MG-63/DOX cells is calculated withthe statistic software SPSS11.5. Result 1. The fluorescence intensity of intracellular ca2+ of MG-63 andMG-63/DOX cells is 41.67±8.32 and 87.52±13.25 respectively inthe control group. The difference between them was significant(P<0.05). In DOX group the fluorescence intensity of intracellularca2+ of MG-63 and MG-63/DOX cells is increased immediatelyunder the effect of various concentrations DOX (1umol/L, 10umol/L,100 umol/L). The fluorescence intensity of intracellular ca2+ ofMG-63 is 48.61±10.61,52.12±12.51 and 64.63±16.35,increasing16.6%,25.1% and 55.1%, respectively, while the fluorescenceintensity of intracellular ca2+of MG-63/DOX is 125.69±23.35,157.36±25.64 and 180.16±22.14, increasing 43.6%,79.8% and105.8%,respectively under the effect of various concentrations DOX(1umol/L, 10umol/L, 100 umol/L).2. The original current of MG-63 and MG-63/DOX cells is(234.16± 14.19) pA and (304.15±14.19) pA respectively in thecontrol group. The difference between them was significant (P<0.05).In DOX group the peak current of MG-63 and MG-63/DOX cells isdecreased when the concentration of DOX is increased. And thepeak current of MG-63 is (216.64±13.12,131.87±17.99 and108.01±16.55) pA, decreasing 7.48% , 43.68% and 53.87%),respectively, while the peak current of MG-63 /DOX is(290.07±12.51,259.20±11.3 and 239.06±10.42) pA, decreasing4.63%,14.78% and 21.4%,respectively under the effect of variousconcentrations DOX (1umol/L, 10 umol/L, 100 umol/L).Conclusion The intracellular concentration of ca2+ ofMG-63/DOX cells is more than one of MG-63 cells in the controlgroup. The DOX can increase the intracellular concentration of ca2+of MG-63 and MG-63/DOX. there is positive dose-related trend thatbehaves more obvious for MG-63/DOX cells. It is concluded that thechange of the intracellular concentration of ca2+ is one of reason ofMDR formation and DOX can activate the ca2+ channels on theendocytoplasmic reticulumof osteosarcoma cells.